* Re: [PATCH net-next v19 5/6] net: dsa: mxl862xx: recover switch stuck in MCUboot rescue mode
@ 2026-10-04 15:56 netdev-bot+sashiko
0 siblings, 0 replies; 3+ messages in thread
From: netdev-bot+sashiko @ 2026-10-04 15:56 UTC (permalink / raw)
To: daniel
Cc: jiri, davem, edumazet, kuba, pabeni, horms, corbet, skhan,
rdunlap, gregkh, rafael, dakr, andrew, olteanv, linux, netdev,
linux-doc, linux-kernel, driver-core
Thank you for your contribution! Sashiko AI review found 6 potential
issue(s) to consider.
Critical: 0 · High: 0 · Medium: 4 · Low: 2
If you believe none of the issues are legitimate, please reply to each
issue of Medium severity or higher and explain why the AI is wrong.
If any of them are legitimate and you plan to respin, please let patchwork
know by including "pw-bot: cr" as a separate line at the end of your reply
(one such reply per series is enough).
- [Medium] Every probe now depends on clause-22 SB PDI access, even on a
switch with healthy firmware.
- [Medium] The drain relies on the claim that 'the drained image never
boots, since its zero fill fails the loader's CRC gate' (comment on…
- [Medium] mxl862xx_setup_rescue() queues the drain on system_long_wq,
created as alloc_workqueue("events_long", WQ_PERCPU, 0) and therefore…
- [Medium] mxl862xx_rescue_mode_detect() takes a single STAT sample as a
definite magic before considering that it could be an outstanding byte…
- [Low] The patch folds a fix for an existing defect in the running-
firmware CRC path into a 660-line feature patch, with no Fixes: tag.
- [Low] The 'Rescue lifecycle' section of the mxl862xx-fw.c file header
says flash_update returns '-EIO for good once the loader cannot accept…
--
net: dsa: mxl862xx: recover switch stuck in MCUboot rescue mode
At setup, this patch checks over the clause-22 SB PDI mailbox whether the
switch is sitting in its MCUboot loader, and does this before any
clause-45 access. In rescue mode the switch is registered without user
ports, so devlink can still reflash it. If a download was interrupted
mid-payload, a background work item drains the loader back to READY and
then re-probes.
> diff --git a/drivers/net/dsa/mxl862xx/mxl862xx-fw.c b/drivers/net/dsa/mxl862xx/mxl862xx-fw.c
> index eae7048707870..eb48fbf7c7115 100644
> --- a/drivers/net/dsa/mxl862xx/mxl862xx-fw.c
> +++ b/drivers/net/dsa/mxl862xx/mxl862xx-fw.c
[ ... ]
> + * Rescue lifecycle (devlink): probe runs mxl862xx_rescue_mode_detect(); a
> + * wedged loader is drained back to READY by a background self-heal
> + * (rescue_heal_work), so the long recovery never holds the devlink lock.
> + * devlink dev info exposes the fw version (the "flashable" signal) only once at
> + * READY; flash_update returns -EBUSY until then, -EIO for good once the
> + * loader cannot accept a download (a failed recovery, or a handshake no
> + * session can finish), and reprobes to WSP firmware on success.
[Severity: Low]
This isn't a bug, but does this list of -EIO causes match the code?
mxl862xx_rescue_heal_work_fn() also sets rescue_failed after a drain that
succeeded, when device_schedule_reprobe() fails with anything other than
-EINVAL. At that point the loader is at a clean READY and can accept a
download. What is lost is only the binding's ability to reclassify the
switch.
The @rescue_failed kernel-doc in mxl862xx.h does list this third cause
("a re-probe that could not be scheduled"). The file header leaves it
out, and "the loader cannot accept a download" is not the reason in that
case.
[ ... ]
> +/* The loader is not asking for a chunk: it may still be programming the last
> + * one, or the counter has reached zero and it is verifying the image and
> + * resetting into READY. Before the first chunk it may also still be erasing
> + * for the session that died, which no verify window covers. Wait that out:
> + * STAT cannot tell the cases apart, and guessing would mean writing END into a
> + * live receive loop. The drained image never boots, since its zero fill fails
> + * the loader's CRC gate, so a count outliving the window is a loader that has
> + * stopped servicing the mailbox.
[Severity: Medium]
Is it guaranteed that the zero fill fails the CRC gate?
Suppose every byte not yet committed when the host died was zero, for
example zero padding at the end of image 2. The zero-filled image then
matches its CRC32. The loader publishes VERIFY_OK (STAT=0), waits for END
and boots the image.
mxl862xx_sb_pdi_poll_drain() treats STAT == 0 as "asks for a chunk", so
the sequence would be:
mxl862xx_rescue_heal_work_fn()
mxl862xx_rescue_drain()
mxl862xx_sb_pdi_poll_drain() returns 0 (the VERIFY_OK verdict)
feeds one more byte (CTRL=WR, DATA=0, reset, STAT=1)
mxl862xx_sb_pdi_poll_drain() sees STAT=1 or the firmware's status word
mxl862xx_rescue_drain_finish(priv, chunk) with chunk > 0
polls 15 s, logs "loader stuck after %u chunks, power cycle it"
returns -EIO
WRITE_ONCE(priv->rescue_failed, true), and no re-probe
Probe can hit the same path. If the STAT == 0 slice-advance in
mxl862xx_rescue_mode_detect() supplies the last outstanding byte, rb is
0, the switch is IN_RESCUE without rescue_ready, and the heal work then
takes the path above.
Wouldn't the driver then stay bound with no user ports, and devlink flash
keep returning -EIO, while the switch runs a verified image? Whether real
images can end in enough zero bytes depends on the image format.
[ ... ]
> + stat = mxl862xx_smdio_read(priv, MXL862XX_SB_PDI_STAT);
> + if (stat < 0)
> + return stat;
> +
> + /* Flashless-download loop (MxL86281S tier): this driver does not
> + * support it -- the console flash path expects READY. Treat it as an
> + * unusable configuration, like any other unsupported state.
> + */
> + if ((u16)stat == MXL862XX_SB_PDI_DL_READY)
> + return -EOPNOTSUPP;
[ ... ]
> + if ((u16)stat == MXL862XX_SB_PDI_START ||
> + (u16)stat == MXL862XX_SB_PDI_START + 1) {
> + WRITE_ONCE(priv->rescue_failed, true);
> + return MXL862XX_IN_RESCUE;
> + }
[Severity: Medium]
Could this single STAT sample be a byte count the loader is still showing,
rather than a magic value?
The loader keeps the host's count in STAT while it programs a chunk and
verifies the image. In mxl862xx_flash_firmware(), the final slice count
that mxl862xx_sb_pdi_flush_last() writes can be anything from 1 to 65520.
That range includes 0xc33c (49980), 0xc55c (50524), 0xf48f (62607) and
0xf490 (62608).
Take a flush_last that fails on an SMDIO read error or its 75 s timeout
while the loader is still programming or verifying the final slice. The
flash path then schedules a re-probe 500 ms later, and setup() runs
detection:
0xc33c fails probe with -EOPNOTSUPP
0xf48f / 0xf490 set rescue_failed for the rest of the binding
0xc55c sends the RDREG challenge to a loader that is not in its
command loop
These checks run before the settle handling and do not depend on it.
Should a count still on display be ruled out before these values are
taken as magics?
[ ... ]
> diff --git a/drivers/net/dsa/mxl862xx/mxl862xx-host.c b/drivers/net/dsa/mxl862xx/mxl862xx-host.c
> index b229c4512b82c..744bbb8d6a24e 100644
> --- a/drivers/net/dsa/mxl862xx/mxl862xx-host.c
> +++ b/drivers/net/dsa/mxl862xx/mxl862xx-host.c
[ ... ]
> @@ -503,6 +511,15 @@ int mxl862xx_api_wrap(struct mxl862xx_priv *priv, u16 cmd, void *_data,
> dev_dbg(&priv->mdiodev->dev, "RET %d DATA %*ph\n", ret, size, data);
>
> out:
> + /* A quiet command is expected to go unanswered by a switch still
> + * booting or sitting in its loader, so it does not arm the shutdown.
> + */
> + if (mxl862xx_crc_failed(ret)) {
> + if (!quiet &&
> + !test_and_set_bit(MXL862XX_FLAG_CRC_ERR, &priv->flags))
> + schedule_work(&priv->crc_err_work);
> + ret = -EIO;
> + }
> mutex_unlock(&priv->mdiodev->bus->mdio_lock);
>
> return ret;
[Severity: Low]
This isn't a bug, but this hunk also fixes behaviour that already exists
in the driver.
In the current code (from commit a319d0c8c8ce), mxl862xx_set_data(),
mxl862xx_get_data() and mxl862xx_rst_data() return mxl862xx_issue_cmd()'s
fw_result unchanged. mxl862xx_api_wrap() then returns it through
"if (ret < 0) goto out". Only mxl862xx_send_cmd() mapped firmware errors
to -EIO.
So a firmware CRC code (-1024/-1023) reported during a multi-chunk
transfer or RST_DATA reached callers as a raw errno, and it never armed
crc_err_work.
Could the central mapping go in as a separate fix with a Fixes: tag, so
it can be backported on its own? The same hunk also stops quiet commands
(the mxl862xx_wait_ready() polls) from arming the CRC shutdown. Before
this patch they did arm it.
> diff --git a/drivers/net/dsa/mxl862xx/mxl862xx.c b/drivers/net/dsa/mxl862xx/mxl862xx.c
> index e6f710c676e65..9097b0c559256 100644
> --- a/drivers/net/dsa/mxl862xx/mxl862xx.c
> +++ b/drivers/net/dsa/mxl862xx/mxl862xx.c
[ ... ]
> + /* Drain the wedged download in the background so it never holds the
> + * devlink lock; info and flash become available once ready.
> + */
> + dev_warn(ds->dev,
> + "switch in MCUboot with an interrupted download, recovering in background\n");
> + queue_work(system_long_wq, &priv->rescue_heal_work);
> +}
[Severity: Medium]
What happens if the system suspends while this drain is running?
system_long_wq is created with alloc_workqueue("events_long", WQ_PERCPU, 0),
so it is not freezable. The driver has no suspend/resume handling. The
drain can run for tens of minutes, with four SMDIO writes and a STAT poll
for every byte.
During suspend, the driver core suspends the mdio_device first, then the
mii_bus, then the MDIO controller, while the kworker keeps issuing bus
accesses.
If one of those accesses returns a bus error, mxl862xx_rescue_drain()
passes it up. mxl862xx_rescue_heal_work_fn() then sets rescue_failed, and
devlink flash returns -EIO until a rebind. On controllers where an access
to a clock-gated block stalls or aborts, the result could be worse.
The work behind device_schedule_reprobe(), which runs right after the
drain, is freezable. Would a freezable workqueue, or some PM coordination,
fit the drain as well?
> static int mxl862xx_setup(struct dsa_switch *ds)
> {
[ ... ]
> - ret = mxl862xx_reset(priv);
> - if (ret)
> - return ret;
> + /* Detect the loader over SB PDI first: it needs no firmware, unlike the
> + * C45 API (mxl862xx_reset/wait_ready), which spends its whole 10 s
> + * window on a mailbox nobody answers. Touch C45 only once rescue is
> + * ruled out.
> + */
> + rescue = mxl862xx_rescue_mode_detect(priv, false);
> + if (rescue < 0) {
> + dev_err(ds->dev, "switch in an unusable state: %pe\n",
> + ERR_PTR(rescue));
> + return rescue;
> + }
[Severity: Medium]
Does this make every probe depend on clause-22 SB PDI access, even for a
switch with healthy firmware?
Before this patch, setup() used only clause-45, through mxl862xx_reset()
and mxl862xx_wait_ready(). Three setups that probe today would now fail.
First, an MDIO host without a ->write callback. __mdiobus_write() returns
-EOPNOTSUPP, and detection passes that straight up:
drivers/net/phy/mdio_bus.c:__mdiobus_write() {
...
if (bus->write)
err = bus->write(bus, addr, regnum, val);
else
err = -EOPNOTSUPP;
...
}
Second, a switch whose SB PDI window has been moved by OTP. The file
header says "the 0xe1xx register offsets are the OTP reset defaults and
the only layout supported here". In that case the ADDR/DATA scratch latch
fails and detection returns -ENODEV.
Third, a single failed clause-22 transfer during the presence check.
wait_ready() used to retry quietly in that situation.
The commit message lists -ENODEV for a switch that "has its SB PDI window
elsewhere". It doesn't mention that this now fails probe for a switch
that works today.
Could -ENODEV or -EOPNOTSUPP from this first detection be treated as
"not in rescue", so probe continues on the clause-45 path?
[ ... ]
--
Sashiko AI review · https://netdev-ai.bots.linux.dev/sashiko/#/patchset/cover.1791035885.git.daniel%40makrotopia.org
^ permalink raw reply [flat|nested] 3+ messages in thread* [PATCH net-next v19 0/6] net: dsa: mxl862xx: devlink flash and rescue @ 2026-10-03 15:50 Daniel Golle 2026-10-03 15:53 ` [PATCH net-next v19 5/6] net: dsa: mxl862xx: recover switch stuck in MCUboot rescue mode Daniel Golle 0 siblings, 1 reply; 3+ messages in thread From: Daniel Golle @ 2026-10-03 15:50 UTC (permalink / raw) To: Jiri Pirko, David S. Miller, Eric Dumazet, Jakub Kicinski, Paolo Abeni, Simon Horman, Jonathan Corbet, Shuah Khan, Randy Dunlap, Daniel Golle, Greg Kroah-Hartman, Rafael J. Wysocki, Danilo Krummrich, Andrew Lunn, Vladimir Oltean, Russell King, netdev, linux-doc, linux-kernel, driver-core This series adds "devlink dev flash" and "devlink dev info" support to the MaxLinear MxL862xx DSA driver, and makes a switch stuck in its MCUboot loader recoverable through the same path. The switch is flashed over the loader's clause-22 SMDIO download interface after the firmware API has rebooted it into MCUboot, and the driver reinitialises through a deferred detach and re-probe once the new image runs. A switch found in MCUboot at probe registers in a reduced rescue mode with firmware version 0.0.0, so the same flash flow recovers it; an interrupted download is drained in the background first. The deferred re-probe comes from a new driver-core helper, device_schedule_reprobe(), which the bound driver calls without a module reference; it also replaces the open-coded self-reprobe that iwlwifi, hci_h5 and btintel_pcie carry, whose work function frees its own module text from under a racing rmmod. fwupd's devlink plugin carries the matching quirks [17]. Patch 3 is a driver-core change and patch 4 does not link without it, so the series needs a driver-core ack before net-next can take it. Tested on an MxL86252C switch of the BananaPi R4 Pro 8X as well as the MxL86282C of Adtran SDG-9000: - an upgrade through `fwupdmgr upgrade` - an unbind and a reboot issued while a flash was running, which wait out the transfer and announce the wait - a host crash (`echo c > /proc/sysrq-trigger`) recovered by the background drain and by the rescue path on the next boot - and a power cut mid-transfer, switch is detected in MCUboot rescue mode on the next boot - an unbind and a reboot issued while a background drain was running, which abort the drain at once and let it resume and complete on the rebind or reboot. Changes since v18 [24]: - patch 3: keep one pending re-probe request per device in struct device_private and cancel it when the device is deleted or its binding ends, so the reference it holds is dropped with the binding and a rebind or a module reload within the delay gets no stale re-probe; drop the error for a re-probe that left the device unbound, since the probe path logs a failed probe itself and a deferred retry is off the deferred-probe list while it runs, so no state read tells it from a failure; drop a request that fires while probing is blocked for a shutdown and re-arm one that fires during a suspend once a second; kernel-doc and commit message corrections (found by Sashiko AI review and a local review) - patch 4: refuse a flash while the DSA tree is still being set up, since devlink registers the switch before the core creates the user ports, which it creates and frees without rtnl held; read the flash gates under the MDIO bus lock in the MDB ops and get_ethtool_stats(); tell devlink when the new firmware runs but the driver needs rebinding; log a rejected image once and name it in the extack; message, comment and kernel-doc corrections; the final slice's verification window moves here from patch 5 (found by Sashiko AI review) - patch 5: map the firmware's CRC verdicts where the command is issued and keep the host's own verdict outside the firmware's result range; confirm READY with the register-read challenge after the settle step too, judged by the re-armed ready word alone; return a bus timeout during the challenge as the bus error it is; drop the "firmware booted while draining" outcome, which the loader's CRC gate makes unreachable, so any count outliving the window is a stuck loader; log a self-heal re-probe that cannot be scheduled; set WORK_STOPPED before waiting out a flash in .remove() and ->shutdown(); drop the unreachable rescue-mode disjunct from the MDB ops; commit message and comment corrections (found by Sashiko AI review) - patch 6: the documentation names every recovery failure with its remedy and says the kernel log names the cause, lists every state without a firmware version, and says that the conduit is closed too, that the reprobe loses the user ports' configuration and that the duration depends on the board's flash chip (found by Sashiko AI review) - patches 1 and 2: commit message corrections, and the comment on the SMDIO helpers names the rescue work among their callers (found by Sashiko AI review) - a local run of the same review pipeline on this version found more, acted on as follows. Patch 3: the unbind cancelled the request before ->remove(), where this driver's flash and drain wait and then schedule, so the cancel moved to the end of the binding, where it also covers a probe that fails; a spinlock pairs the slot with the queueing and cancelling of its work, which closes the windows between publishing and queueing a request and around the re-arm; the slot is held until the work has released the driver, so a second request during a re-probe is refused. Patch 4: the DSA workqueue is flushed after the ports close, so the bridge's host address deletions reach the firmware while it still runs; the chip ID is zeroed before it is re-read; the unreachable component check is gone. Patch 5: rescue mode counts among the gates get_ethtool_stats() keeps quiet for, the CRC codes are logged as reported, -EINVAL from the self-heal's request is the device deletion it is, and the probe-time messages name the state. Patch 6 and the messages of patches 1 and 2 follow. A second pass on that result found less: patch 3 drops the driver pointer and name copy, which the slot makes redundant, and re-arms across a hibernation restore; patch 4 takes -EINVAL from the re-probe request as the device deletion it is; patch 5 returns a bus error of the challenge's closing reset as such and names the host's CRC verdict in the log; the rest is prose - Andrew's Reviewed-by is kept on patches 1, 2 and 6, which changed in prose only - the Sashiko review's remaining findings are not acted on: a refused FW_UPDATE command keeps the teardown and re-probe, since the ports are closed by then and the re-probe is what reinitialises them, and the log and extack name the refusal; the wait of a reboot for a flash in flight is announced in the log and ends with the transfer; a switch left unbound by a failed re-probe hand-off is a rebind matter, as documented; an MDIO bus without clause-22 access cannot carry this switch, as no SoC or MAC on a real board exposes one without both clauses; a final slice whose byte count equals a status magic holds that value only while the loader programs the slice, well before a host that died could probe again; the drain stays off a freezable workqueue, a suspend during the exceptional recovery path being rare and recovered by a rebind; and a running firmware never holds 0 in the status register, which reads 0x0003 after boot whatever the loader left behind, as observed on the BananaPi BPi-R4 Pro 8X after a flash and after a plain rebind; a status word left at 0 by an END write that failed is not guarded against either, since a clause-22 write failing after the hundreds the transfer made is a broken bus, which the readiness poll that follows fails on as well. - the changes to patches 1 to 6, the commit messages of patches 1 and 2 included, were written with an LLM coding assistant working from the Sashiko findings and a local review, and reviewed by hand; the Assisted-by tags on patches 3 to 6 record this Changes since v17 [23]: - patch 3: re-arm the work while probing is blocked, since dpm_prepare() blocks it as well and a kexec jump or a kernel without the suspend freezer reaches that window with the workqueue running, which lost the request for good; log an error for every unbound outcome of device_attach() except a deferred probe, a failed probe coming back as 0, which the check for a negative value missed; kernel-doc and commit message corrections (found by Sashiko AI review) - patch 4: accept a read refused by the flash gate or the teardown gate while either is set in port_mdb_add() and port_mdb_del(), since the flash moves from one gate to the other after api_wrap() has dropped the MDIO bus lock; wait for the header byte count to change rather than for its ACK value, which a short erase retires between two polls; log a re-probe that cannot be scheduled after a failed transfer as well; return silently from get_ethtool_stats() while the gates refuse reads, which unprivileged ethtool -S reaches (found by Sashiko AI review) - patch 5: after a failed clause-45 wait, a status word that outlives the settle step is rescue only when it is the erase count of the session that died; any other value is a firmware that answered the reset without becoming ready, and probe fails with the wait error as it did before the patch; the rescue-mode version is reported as running only, since the driver cannot tell what the flash holds; the probe-time log names the interrupted handshake and the extack covers every failed-recovery cause; the commit message describes the detection outcomes again (found by Sashiko AI review); a quiet firmware command, as the readiness poll issues, does not arm the CRC-error work, since a probe that meets the loader mid-erase fails every poll's CRC check and closed the conduit with a warning on each - patch 6: the documentation follows the patch 4 and 5 changes - Andrew's Reviewed-by is kept on patches 1, 2 and 6, whose only change this round is two sentences of documentation - the review's remaining findings are not acted on: an MDIO bus without clause-22 access cannot carry this switch, as no SoC or MAC on a real board exposes one without both clauses, so its absence is not handled; a final slice whose byte count equals a status magic holds that value only while the loader programs the slice, well before a host that died could probe again; the drain's chunk == 0 error was raised again and the v16 note below stands, the one path that fed a running firmware into the drain being the settle classification patch 5 now corrects; the ->remove()-after-->shutdown() window and the two patches between which a failed transfer is not yet recovered are described in the commit messages of patches 3 and 4; and the drain stays off a freezable workqueue as in v17 - the changes to patches 3 to 6 were written with an LLM coding assistant working from the Sashiko findings, and reviewed by hand; the Assisted-by tags on patches 3 to 6 record this Changes since v16 [21]: - patch 3: drop the abort_if_blocked flag and the bool return of __device_release_driver(), leaving that function unchanged. The flag left the device-links state half torn down when it fired and did not cover the consumers unbound in the same window; the shutdown-versus- release window it targeted is pre-existing to every unbind path (driver_detach(), unbind_store(), the consumer recursion), so the re-probe, which is device_reprobe() deferred, shares it rather than introducing it, and the kernel-doc now says so (found by Sashiko AI review) - patch 3: record the bound driver's name beside its pointer and compare both, so a freed struct device_driver address the allocator later hands to a different driver is not mistaken for the original binding; this closes the recorded-identity race without a module reference (found by Sashiko AI review) - patch 4: wait out a flash in flight in .remove() as ->shutdown() already did, before dsa_unregister_switch() frees the user netdevs. The instance lock a flash holds does not cover that free, which the teardown reaches first, so an unbind racing a flash could touch a freed netdev; both paths now take the lock up front and announce the wait with dev_info() so the up-to-a-minute pause is not mistaken for a hang (found by Sashiko AI review) - patch 4: report success for a firmware read blocked by a flash (-EBUSY), not only the teardown -ENODEV, in port_mdb_add() and port_mdb_del(), so an MDB change racing a flash does not fail and leave the entry linked; clear the SB PDI ADDR and DATA latches with 0 rather than a CTRL mode value that only happens to be 0; log that a rebind is needed if the re-probe cannot be scheduled after the new firmware is already running; correct the block_host/skip_teardown kernel-doc to the policy the code implements (all found by Sashiko AI review) - patch 5: bypass the firmware-version gate in mxl862xx_phylink_get_caps() in rescue mode, so a SerDes CPU port does not get an empty supported_interfaces mask and fail phylink_create(), matching the mac_select_pcs() bypass; the @rescue_failed kernel-doc and the setup log message no longer prescribe a power cycle for every cause, whose per-cause remedy is in the documentation (found by Sashiko AI review) - Andrew's Reviewed-by is kept on patches 1, 2 and 6, unchanged this round - Jakub asked whether the mode transitions could be driven from userspace through devlink reload [22]. The deferred re-probe is kept: DSA has no reload plumbing, and adding it would need a new DSA-core path to reinitialise a switch while its devlink instance stays alive, whereas the re-probe reuses the existing unbind/register path, and the helper it uses is wanted regardless to replace the open-coded self-reprobe in iwlwifi, hci_h5 and btintel_pcie - patch 5: the interrupted-download drain's chunk == 0 error, which the review reads as mis-reporting a firmware that booted mid-drain, was reproduced on hardware and does not arise. The loader verifies the received image by CRC, so the zero-filled drain never reconstructs a bootable image; it returns the loader to its ready state instead, and the chunk == 0 error only fires for a genuinely wedged loader, where it is correct (found by Sashiko AI review) - the review's remaining findings are not acted on: patch 1 stays on the unconditional shared ops table as Andrew asked in v9; the SB PDI register offsets and the status words patch 5 classifies the switch by are a fixed hardware property configured by MCUboot and a stable contract the firmware release QA gates enforce, probe detection being part of the gate, so neither a relocated window nor a status value that breaks classification is a configuration that ships; and the background drain deliberately stays off a freezable workqueue, a suspend or bus error there being a rare event on an exceptional path that a rebind recovers - the changes to patches 3 to 5 were written with an LLM coding assistant working from the Sashiko findings and a local review, and reviewed by hand; the Assisted-by tags on patches 3 to 5 record this Changes since v15 [20]: - patch 1: the commit message no longer puts a notification pair around a missing firmware file; the core fails that before the pair, which wraps the call into the trampoline only - patch 3: take no lock in the caller's context and drop the parent snapshot, refusing buses that need the parent lock instead. The caller-context device lock inverted against the devlink instance lock, which a flash holds across the call, and against the synchronous cancel of the rescue self-heal work; a pinned parent can also be freed by device_move(). Only usb_bus_type sets need_parent_lock, and the conversions posted separately re-probe PCI and serdev devices, so none of them is refused. Patches 4 and 5 need no change of their own for either inversion (all found by Sashiko AI review) - patch 3: abandon the release when probing gets blocked while __device_release_driver() has the locks dropped to unbind busy consumer links, closing the one window where a ->remove() could follow a ->shutdown(). Earlier versions called it pre-existing, which it is, but a deferred re-probe is the one unbind that may be abandoned, so it takes a flag the other callers do not (found by Sashiko AI review) - patch 3: the commit message now describes what this patch changes rather than bugs in the drivers it does not convert (found by Sashiko AI review) - patch 3: the commit message no longer claims the detach is synchronised with device_shutdown() in every case. Probing is blocked only once wait_for_device_probe() has returned, so a re-probe already past the check detaches the device, which then runs ->remove() in place of ->shutdown() - patch 4: a firmware write blocked by a running flash reports success instead of -EBUSY. Tearing a bridge down over a flash, as a reboot does, made port_vlan_del() fail; the bridge then leaves the VLAN on its list and __vlan_group_free() warns and frees the group with the entries still linked - patch 4: ->shutdown() now waits for a flash in flight and refuses one requested after it, so a reboot cannot cut the image in half. The devlink core already serialises .remove() through the instance lock; ->shutdown() does not go through devlink and takes that lock itself - patch 4: the -EBUSY extack of a pending reprobe states a fact rather than advising a retry, and the comment on mxl862xx_read_chip_id() drops the rescue-mode cache that only patch 5 creates - patch 4: select CRC32, which nothing else selects for the image checksum validation (found by Sashiko AI review) - patch 5: treat a byte count outliving the settle step as a busy loader and wait out an erase a dead session left running before draining, so a host that died during the loader's erase no longer fails probe with the -ETIMEDOUT this series exists to avoid; drop the loader's clean ready state with the cached identity when a flash fails; state facts only in the extack of a failed recovery (all found by Sashiko AI review) - patch 5: the commit message and the comments no longer say the clause-45 API floods the log with CRC errors when no firmware answers. The mailbox commands run into their timeouts instead, and testing the stuck-in-MCUboot paths produces no such message; what probing SB PDI first saves is the ten seconds of polling and the -ETIMEDOUT that ends probe - patch 5: move the rescue branch of mxl862xx_setup() into a function of its own, which brings its messages back inside 100 columns; state a fact in the -EBUSY extack of a running recovery; trim the drain comment, whose protocol detail is in the file header, and order its declarations - patch 6: document that the ports come back down, which recovery failure needs a power cycle and which a rebind, and what a re-probe that cannot be scheduled leaves behind (found by Sashiko AI review) - patch 6: document that a reboot waits for a running flash, that a flash requested after it is refused, and that a bus error ends the download recovery for good; title-case the "Flash Update" heading like the other devlink driver documents - Andrew's Reviewed-by is kept on patches 1, 2 and 6: patch 1 gained commit message text only and patch 6 the documentation sentences above. It is dropped on patch 4, which gained the shutdown serialisation - patch 3 has drawn no driver-core reply here or in its three standalone postings [11][14]. The helper is no longer an RFC: Hans de Goede reviewed and tested it there [15][16], and the conversions of the open-coded users in iwlwifi, hci_h5 and btintel_pcie follow once this series is merged - the remaining findings of that review are not acted on: patch 1 is asked once more to install .flash_update only for drivers implementing the callback, as v4 did, and stays unconditional as Andrew asked in v9; the empty supported_interfaces a rescue-mode probe leaves for the quad-mode sub-interfaces can only reach phylink through a CPU port on one of them, which the chip does not support; and the driver pointer patch 3 records could in theory match a different driver loaded at the same address within the delay, at the cost of one spurious re-probe - the changes to patches 1 and 3 to 6, the commit message of patch 1 included, were written with an LLM coding assistant working from the Sashiko findings and from a local review of the posted series, and reviewed by hand; the Assisted-by tags on patches 3 to 6 record this Changes since v14 [19]: - patch 3: skip the detach while probing is blocked, which device_shutdown() does before its walk reaches any device, instead of a per-device flag set only once the walk arrives; validate the device and snapshot the parent, its locking requirement and the bound driver under the device lock; keep -EPROBE_DEFER out of the re-probe error path so it cannot overwrite a deferred probe reason (all found by Sashiko AI review) - patch 4: treat the closing END write as advisory, since the loader has verified the image by then, and admit only the flash task's own firmware reads past block_host instead of every read from every context (found by Sashiko AI review) - patch 5: classify a status register left in the download handshake as a loader needing a power cycle rather than as running firmware, give the loader one step to publish its next state before ruling it out after a failed clause-45 wait, abort the drain polls as soon as teardown asks for it instead of stalling unbind for up to 17 s, and pair the rescue_mode accesses with WRITE_ONCE()/READ_ONCE() (all found by Sashiko AI review) - patch 6: asic.rev comes from the CHIP ID registers as well, and -EIO means the driver gave up on the recovery, which may need a rebind rather than a power cycle (found by Sashiko AI review) - Andrew's Reviewed-by is kept on patches 1, 2, 4 and 6; the changes to 4 and 6 are the two small ones above and a documentation reword - the same review asks again whether patch 1 should install .flash_update only for drivers implementing the callback, as v4 did; it stays unconditional as Andrew asked in v9. Its remaining findings are not acted on either: the pre-existing window in __device_release_driver() where a ->shutdown() can interleave with a release, which every unbind path shares; the recorded driver pointer, which an unbind and rebind within the delay can match again at the cost of one spurious re-probe; and the get_stats64() re-arm race in remove(), which predates this series and is fixed separately for net - the changes to patches 3 to 6 were written with an LLM coding assistant working from the Sashiko findings and reviewed by hand; the Assisted-by tags on those patches record this Changes since v13 [18]: - patch 5: initialise the SerDes state once mxl862xx_wait_ready() has cached the firmware version, still before the rescue-mode early return, so PCS setup can depend on the running firmware - picked up Andrew's Reviewed-by on patches 1 and 4; the one on patch 5 is not carried as that patch changed - the Sashiko review of v13 repeats the ABA finding on patch 3 dismissed in v13 and marks the two __device_release_driver() windows and the get_stats64() re-arm race as pre-existing; no change - the change to patch 5 was written with an LLM coding assistant working from a report against a downstream tree and reviewed by hand; the Assisted-by tag on that patch records this Changes since v12 [13]: - v12 went out just as net-next closed for the 7.3 merge window. The helper of patch 3 was then posted on its own, with conversions of the existing open-coded users in iwlwifi, hci_h5 and btintel_pcie, most recently as v3 [14], which Greg's patch bot deferred past the merge window; Hans de Goede reviewed and tested the helper and the hci_h5 conversion there on RTL8723BS hardware [15][16]. The Sashiko review of that posting found the same issues in the helper as the review of v12 did, so patch 3 here supersedes the helper patch of that series; once this series is merged, the conversions follow as patches for bluetooth-next and wireless-next. On the userspace side, fwupd's devlink plugin has meanwhile gained the quirks for these switches [17] - patch 3: queue the re-probe on system_freezable_wq, so one pending across system suspend runs after resume instead of detaching a suspended device or racing its late suspend callbacks; record at scheduling time whether the parent needs locking instead of reading dev->bus, which may be gone with its module once the device was unregistered; let __device_release_driver() report whether it released the driver, so an administrative unbind that wins the race inside the device links loop is not undone by the re-attach (all found by Sashiko AI review); use dev_err_probe() for the re-probe error path (Hans de Goede) - patch 4: stop the stats poll with disable_delayed_work_sync() in the flash path, so a racing get_stats64() re-arm is a no-op, and drop the early return in the work function; the v12 reordering of remove() is gone as well, since the get_stats64() race it addressed predates this series and needs a fix of its own (found by Sashiko AI review) - two further findings of the same review are not acted on: the recorded driver pointer could in theory match a different driver loaded at the same address within the delay, which would cost that driver one spurious detach and re-probe; and the final put_device() from the work could call a release() whose module was unloaded in the meantime, which is the same hazard every asynchronous device reference in the core carries, the async probe helper included - the changes to patches 3 and 4 were written with an LLM coding assistant working from the Sashiko findings and reviewed by hand; the Assisted-by tags on those two patches record this Changes since v11 [12]: - patch 3: pin the parent device across the deferred re-probe and take the parent lock across device_attach() on buses that need it; a reference on the child alone left a freed dev->parent dereferenced under __device_driver_lock() (found by Sashiko AI review) - patch 4: cancel the stats poll after dsa_unregister_switch() so a racing get_stats64() cannot re-arm it against freed priv; and keep the host blocked for writes across the post-flash readiness poll, letting only the flash path's own reads reach the new firmware (found by Sashiko AI review) Changes since v10 [10]: - new patch 3: driver core: add device_schedule_reprobe(), as posted in the RFC [11], used to schedule the post-flash and post-drain re-probe with device_schedule_reprobe() instead of a driver-owned work item. - the dsa_switch allocation returns to devres. Keeping it out of devres only defused the remaining check-vs-detach window, which the core helper closes outright - scheduling the re-probe is now the one step that can fail after the switch was flashed, since the helper allocates its work item internally and v10's allocate-up-front dance is no longer possible. An -ENOMEM there is a system-wide condition no driver-level message or recovery improves, so flash_update just returns it (unbind and rebind reinitialises the driver), and a drain whose hand-off fails still marks recovery failed so devlink does not keep promising a retry Changes since v9 [9]: - Harmonised the SB PDI timeouts. The verify wait is now one constant shared by the flash and drain paths (15 s), the 1-byte mailbox step is another (2 s) used by the drain and by both detection waits, and the per-slice write budget drops from 120 s to 60 s. The last-slice flush, which cannot see the boundary between programming and verifying, gets the sum of the two. - The post-flash and post-drain reprobe no longer detaches a device that has been shut down or unbound, and the dsa_switch is allocated outside devres so a lost race cannot leave dsa_switch_find() reading freed memory. This was a live bug in v9's patch 3 as well, reachable by rebooting within 500 ms of a flash. - A failed reprobe hand-off after a successful drain now logs and fails flashing outright, instead of leaving devlink answering "retry shortly" for good. Dropped heal_lock and mxl862xx_stop_work() with it: the lock only made the flag test and the queueing atomic, which is not the guarantee the comment claimed, and the reprobe's own check is what actually decides now. - A loader that publishes READY but never services the register-read challenge now reports -ENXIO rather than propagating -ETIMEDOUT, and the documented return sets of mxl862xx_rescue_mode_detect() and mxl862xx_rescue_drain_finish() match what the code returns. - Commit message for patch 4 no longer claims a running firmware is "left untouched" (the presence probe writes two mailbox scratch registers, inert to a firmware that does not read them), says that an SB PDI window away from the OTP reset offsets also yields -ENODEV, and describes the -ENXIO outcome above. - Commented why STAT == 0 during a drain is unambiguous: by the r_remain == 0 rule the loader cannot be both inside the receive loop asking for a chunk and publishing a verdict. - Documented that a switch power cycled on its own needs the driver unbound and rebound before a failed recovery is re-examined. Changes since v8 [8]: - install the flash_update devlink op unconditionally and return -EOPNOTSUPP from the trampoline for drivers without the callback, instead of a second devlink_ops permutation (Andrew Lunn) - picked up Andrew's Reviewed-by on patches 2 and 5, given on v5 Changes since v7 [7]: - most of the changes below address findings of the Sashiko AI reviews of v7 - the MCUboot loader's transfer completion was reverse-engineered to settle two of them: it publishes an image verification verdict in its status register, finalises without the END magic once a 2 s timeout expires, and keeps the host's byte count visible while it programs a chunk. The interrupted-download drain therefore no longer sends END, which a loader still in its receive loop consumes as a byte count and underflows its receive counter on, and the flash path now reports a rejected image instead of a write timeout - refuse a second devlink dev flash while the previous one's reprobe is still pending, and stop publishing a zeroed firmware version after a failed transfer - initialise the SerDes state before the rescue-mode early return, so a successful rescue-mode flash cannot hand phylink an unconfigured PCS - do not fail probe from the wedged-download branch of the rescue detection, which a download interrupted with exactly one byte outstanding would trigger, and report a failed recovery through devlink rather than refusing every flash for good - reset the SB PDI mailbox before probing it, log the drain's progress, and correct the protocol and register comments throughout Changes since v6 [6]: - reprobe from a single delayed work item instead of a kthread spawned by a workqueue kickoff; the kthread existed only to drop the module reference from core code, but its creation-failure path did the racy module_put() from module text anyway and could strand the driver bound with skip_teardown set. The collapsed form matches iwl_trans_reprobe_wk(), and a failed reprobe now leaves the device unbound like a failed probe - only signal END on a successful transfer; a failure leaves the loader mid-payload, where END is read as a byte count and can underflow the receive counter, so return the error and let the reprobe recover - add cond_resched() to the payload loop so a long transfer over a bit-banged MDIO bus under CONFIG_PREEMPT_NONE does not trip the soft-lockup detector - drop the cached firmware version and chip id on a failed flash so devlink dev info stops reporting the pre-flash version until the reprobe - report the firmware version under DEVLINK_INFO_VERSION_GENERIC_FW instead of a bare "fw" string - correct the SB PDI header comment's SMDIO register map and expand the note on why closing the shared conduit is safe Changes since v5 [5]: - run the post-flash reprobe from a kthread that drops the module reference with module_put_and_kthread_exit() from core code, fixing a use-after-free where a work item's trailing module_put() could return into module text a racing rmmod had freed; a workqueue kickoff spawns the kthread off the devlink caller where kthread_create() can return -EINTR - send END on every flash failure from the ready handshake onward so an aborted transfer lets MCUboot reboot instead of leaving it waiting - after the background drain finalises an interrupted download, reprobe and let the probe-time detection re-classify the switch, so a valid image a last-moment interruption left bootable comes up as running firmware; rescue_drain() no longer inspects or reports the outcome - re-read the SB PDI status register once more after a poll timeout expires, so a preempted poll cannot report a spurious -ETIMEDOUT - bail out of the periodic stats poll when the flash teardown has set WORK_STOPPED, closing a get_stats64() re-arm race - allocate the reprobe kickoff before disturbing the switch, so an -ENOMEM cannot leave it flashed but never reprobed - omit asic.id/asic.rev when the CHIP ID read returned 0, instead of publishing a bogus "0000" for fwupd to match firmware against - treat the flashless-download loop (STAT 0xc33c) as an unsupported configuration and fail probe with -ENODEV instead of advertising it as flashable Changes since v4 [4]: - report the numeric chip part number and version read from the static CHIP ID registers as the "asic.id" and "asic.rev" fixed versions instead of a model-name string, which does not belong in a devlink version identifier (Jakub Kicinski) - report the running firmware version as the "stored" version too, since the switch boots it from its own flash, so userspace can distinguish a flash-backed part from a flashless one by the presence of "stored" without a future API change - run the post-flash reprobe from a self-contained work item again instead of the v4 kernel thread, which tripped the hung-task watchdog while parked across the flash and returned -EINTR from kthread_create() when the devlink command was interrupted - re-read the new firmware version through the reprobe's fresh probe and drop the SYS_MISC_FW_VERSION exemption from the host block - raise the firmware command poll timeout so the FW_UPDATE command that reboots into MCUboot is not cut short - detect the switch state from the value MCUboot publishes in the SB PDI STAT register (loader ready, wedged download, or running firmware), confirming a live console loader with a register-read challenge, instead of trusting a bare SMDIO scratch write - fail probe with -ENODEV over SB PDI when the switch does not respond at all (absent, unpowered, or misdescribed in the device tree) instead of letting the clause-45 API flood the log with CRC errors - drain a wedged interrupted download back to a clean ready state from a background work item so the multi-minute recovery never holds the devlink instance lock, reporting no firmware version and refusing flash with -EBUSY until it completes - report the rescue-mode null firmware version "0.0.0" as both the running and stored version, matching the running/stored reporting above - split the devlink documentation into its own patch and add Documentation/networking/devlink/mxl862xx.rst describing the info versions and the flash update behaviour (Jakub Kicinski) - include example "devlink dev info" outputs in the commit messages of patches 3 and 4 (Jakub Kicinski) Changes since v3 [3]: - only install the flash_update devlink op for switches whose driver implements it, so the devlink core rejects unsupported requests before fetching the firmware file from userspace - run the deferred reprobe from a kernel thread which ends in module_put_and_kthread_exit() instead of a work item that dropped its module reference while still executing module code - fail firmware API read commands with -ENODEV after the update has finished instead of faking success with an unfilled buffer, which could send port_fdb_dump() into an endless loop - keep the host block in place across the post-update version query by exempting SYS_MISC_FW_VERSION from block_host instead of briefly lifting the block, and write all blocking flags under the MDIO bus lock - check the return value of all SB PDI control writes; a failed address write during the half-bank switch could otherwise place the second half of the payload at the wrong flash offset - initialise the progress notification deadline from jiffies so notifications are not suppressed on 32-bit systems shortly after boot - log a distinct diagnostic when rescue mode detection fails on an SMDIO bus error instead of silently treating it as not being in rescue mode - flush the switchdev deferred queue after closing the ports so the bridge's deferred STP DISABLED transitions reach the firmware while it is still running instead of failing against the host block with "failed to set STP state" errors - treat -ENODEV as successful deletion in port_mdb_del() so the post-update teardown no longer leaves host MDB entries behind for the DSA core to report when the tree is torn down Changes since v2 [2]: - validate the firmware image, including both CRCs, before taking down any ports, so that a malformed file is rejected without disturbing the running switch and without the needless flash and reprobe cycle it previously triggered - reject images whose declared payload sizes overflow when summed (check_add_overflow) or sum up to zero; the latter previously erased the flash without writing anything back - allocate the reprobe work item and take the module and device references before starting the update, so scheduling the reprobe can no longer fail after the switch has been pushed into MCUboot - prevent the stats poll work from being re-armed and cancel the CRC error work before starting the transfer - check the host-blocking flags in mxl862xx_api_wrap() under the MDIO bus lock to close the race window where an API command which had already passed the check could reach the bus after the switch rebooted into MCUboot - check the return value of SB PDI data word writes so a failed MDIO transaction aborts the transfer instead of being noticed only through a corrupted image - report a per-model chip name (e.g. "MaxLinear MxL86252") as the devlink "asic.id" fixed version instead of the devicetree compatible string, whose comma is awkward for userspace consumers such as fwupd (see discussion on v2 patch 3) - report the canonical null version "0.0.0" instead of "mcuboot-rescue" as the running firmware version in rescue mode, so that version-comparing update tools like fwupd treat every available release as an upgrade and offer it for recovery Changes since RFC [1]: - detect a switch stuck in MCUboot rescue mode at probe, register the switch without any ports and report "mcuboot-rescue" as the running firmware version, so devlink flash can recover from a failed or interrupted update (Andrew Lunn) - clarify in the commit message of patch 2 that the per-transaction MDIO bus locking is about other, non-switch devices on the same MDIO bus (Andrew Lunn) - mention in the commit message of patch 3 that closing the ports also stops phylib from polling the switch-internal PHYs during the transfer (Andrew Lunn) - split up run-on sentence and explain the dynamically allocated reprobe work item instead of just pointing at iwlwifi in the commit message of patch 3 (Manuel Ebner) - use kzalloc_obj() (Manuel Ebner) - state the actual duration of a complete flash and reprobe cycle (just under a minute) in comments and the commit message, and clarify that the timeout values are generous upper bounds (Manuel Ebner) [1] https://lore.kernel.org/all/ak0J-HgzMRea53om@makrotopia.org/ [2] https://lore.kernel.org/all/cover.1783988826.git.daniel@makrotopia.org/ [3] https://lore.kernel.org/all/cover.1784513694.git.daniel@makrotopia.org/ [4] https://lore.kernel.org/all/cover.1784665017.git.daniel@makrotopia.org/ [5] https://lore.kernel.org/all/cover.1784945329.git.daniel@makrotopia.org/ [6] https://lore.kernel.org/all/cover.1785119999.git.daniel@makrotopia.org/ [7] https://lore.kernel.org/all/cover.1785274610.git.daniel@makrotopia.org/ [8] https://lore.kernel.org/all/cover.1785389905.git.daniel@makrotopia.org/ [9] https://lore.kernel.org/all/cover.1785728574.git.daniel@makrotopia.org/ [10] https://lore.kernel.org/all/cover.1786294649.git.daniel@makrotopia.org/ [11] https://lore.kernel.org/all/anpxFdwNxk0XwPjQ@makrotopia.org/ [12] https://lore.kernel.org/all/cover.1786773971.git.daniel@makrotopia.org/ [13] https://lore.kernel.org/all/cover.1786922210.git.daniel@makrotopia.org/ [14] https://lore.kernel.org/all/cover.1787281239.git.daniel@makrotopia.org/ [15] https://lore.kernel.org/all/c461462f-de0b-43e8-ac9e-541013f5f8da@oss.qualcomm.com/ [16] https://lore.kernel.org/all/7ffe0c2e-0742-488a-ab6c-1dc2fabc049c@oss.qualcomm.com/ [17] https://github.com/fwupd/fwupd/commit/e50c9e5ab39d31242e664efbbf441fd46d15a0cd [18] https://lore.kernel.org/all/cover.1788783126.git.daniel@makrotopia.org/ [19] https://lore.kernel.org/all/cover.1788976064.git.daniel@makrotopia.org/ [20] https://lore.kernel.org/all/cover.1789175618.git.daniel@makrotopia.org/ [21] https://lore.kernel.org/all/cover.1789477568.git.daniel@makrotopia.org/ [22] https://lore.kernel.org/all/aq5QDmuQnqQTudca@makrotopia.org/ [23] https://lore.kernel.org/all/cover.1790130482.git.daniel@makrotopia.org/ [24] https://lore.kernel.org/all/cover.1790426599.git.daniel@makrotopia.org/ Daniel Golle (6): net: dsa: add devlink flash_update callback to dsa_switch_ops net: dsa: mxl862xx: add SMDIO clause-22 register access driver core: add device_schedule_reprobe() net: dsa: mxl862xx: add devlink flash_update and info_get net: dsa: mxl862xx: recover switch stuck in MCUboot rescue mode net: dsa: mxl862xx: document devlink flash and info support Documentation/networking/devlink/index.rst | 1 + Documentation/networking/devlink/mxl862xx.rst | 118 ++ MAINTAINERS | 1 + drivers/base/base.h | 5 + drivers/base/core.c | 1 + drivers/base/dd.c | 172 +++ drivers/net/dsa/mxl862xx/Kconfig | 1 + drivers/net/dsa/mxl862xx/Makefile | 2 +- drivers/net/dsa/mxl862xx/mxl862xx-api.h | 10 + drivers/net/dsa/mxl862xx/mxl862xx-cmd.h | 2 + drivers/net/dsa/mxl862xx/mxl862xx-fw.c | 1188 +++++++++++++++++ drivers/net/dsa/mxl862xx/mxl862xx-fw.h | 21 + drivers/net/dsa/mxl862xx/mxl862xx-host.c | 143 +- drivers/net/dsa/mxl862xx/mxl862xx-host.h | 3 + drivers/net/dsa/mxl862xx/mxl862xx-phylink.c | 9 +- drivers/net/dsa/mxl862xx/mxl862xx.c | 187 ++- drivers/net/dsa/mxl862xx/mxl862xx.h | 56 +- include/linux/device.h | 2 + include/net/dsa.h | 3 + net/dsa/devlink.c | 13 + 20 files changed, 1894 insertions(+), 44 deletions(-) create mode 100644 Documentation/networking/devlink/mxl862xx.rst create mode 100644 drivers/net/dsa/mxl862xx/mxl862xx-fw.c create mode 100644 drivers/net/dsa/mxl862xx/mxl862xx-fw.h base-commit: 42a9fb3382fc2573e92f41d203b095d9a372cfc9 -- 2.56.0 ^ permalink raw reply [flat|nested] 3+ messages in thread
* [PATCH net-next v19 5/6] net: dsa: mxl862xx: recover switch stuck in MCUboot rescue mode 2026-10-03 15:50 [PATCH net-next v19 0/6] net: dsa: mxl862xx: devlink flash and rescue Daniel Golle @ 2026-10-03 15:53 ` Daniel Golle 2026-10-04 14:45 ` Andrew Lunn 0 siblings, 1 reply; 3+ messages in thread From: Daniel Golle @ 2026-10-03 15:53 UTC (permalink / raw) To: Jiri Pirko, David S. Miller, Eric Dumazet, Jakub Kicinski, Paolo Abeni, Simon Horman, Jonathan Corbet, Shuah Khan, Randy Dunlap, Daniel Golle, Greg Kroah-Hartman, Rafael J. Wysocki, Danilo Krummrich, Andrew Lunn, Vladimir Oltean, Russell King, netdev, linux-doc, linux-kernel, driver-core A broken or interrupted firmware image, or the sticky rescue bit, keeps the switch in its MCUboot loader, which exposes only the clause-22 SMDIO download interface. The clause-45 firmware API never comes up there, so an ordinary probe would spend its whole timeout on a mailbox nothing answers before failing. Detect the loader over SB PDI at setup, ahead of any clause-45 access. The mailbox is reset and a scratch write to it must latch, or the switch is absent or has its SB PDI window elsewhere (-ENODEV); the status word then names the state. A console loader is confirmed with a register-read challenge, which only the loader's command loop services by re-arming its ready word, and refused with -ENXIO when the challenge goes unserviced. The loader's flashless download loop is unsupported (-EOPNOTSUPP), an interrupted opening handshake is rescue that only a power cycle clears, and a zero byte count is a receive loop wedged mid-payload. A running firmware holds any other value and sees nothing but the mailbox resets and scratch writes, which land in registers it never reads. In rescue mode register the switch without user interfaces so devlink stays available to reflash it: the user ports fail setup and the DSA core re-registers them as unused, while the shared and CPU ports come up, the CPU port on its fixed link. devlink dev info then reports the running firmware version as "0.0.0", which no released firmware carries, so fwupd offers every release as an upgrade and recovers the switch through the regular flash flow; no stored version is reported, since what the flash holds is unknown in the loader. An interrupted download can leave the loader wedged mid-payload with an outstanding byte count. A background work item off the devlink flash path drains it back to a clean ready state by feeding that count one byte at a time, since a larger step could underflow the loader's counter and wedge it until a power cycle, then re-probes so the probe-time detection reclassifies the switch. Until it finishes, devlink dev info reports no version and devlink dev flash returns -EBUSY. A loader left in its opening handshake, a drain that fails and a re-probe that cannot be scheduled are final for the binding: devlink dev flash then returns -EIO. A probe that meets the loader while it still erases for a session that died runs the clause-45 readiness poll against it, and every poll fails its CRC check there. The poll's reads are quiet ones, issued in the knowledge that a switch in its loader or still coming out of reset may not answer, so a quiet command leaves the CRC-error work alone; only a command against a firmware believed to be running arms it. mxl862xx_api_wrap() recognises the CRC codes at its exit, whichever step reported them, so the data transfer steps cannot pass a firmware CRC code up raw; the host's own verdict is a code outside the firmware's result range, so no firmware errno can be taken for it. Assisted-by: LLM Signed-off-by: Daniel Golle <daniel@makrotopia.org> --- v19: - recognise the firmware's CRC codes at the exit of mxl862xx_api_wrap() whichever step reported them, so the data transfer steps no longer pass them up raw, and give the host's own verdict a code outside the firmware's result range, which -EBADMSG was not; the command log keeps the code as reported (found by Sashiko AI review and a local review) - count rescue mode among the gates mxl862xx_api_gated() reports, so an unprivileged ethtool -S on the conduit stays silent in rescue mode (found by a local review) - treat -EINVAL from the self-heal's re-probe request as the device deletion it is, which ends the work anyway (found by a local review) - extack of a switch that cannot be flashed from its binding and the probe-time messages for an unusable switch state name what happened, and the command log names the host's own CRC verdict as such (found by a local review) - return a bus error of the reset closing the register-read challenge as such, which -ENXIO hid when the poll had also expired (found by a local review) - commit message: the three states that are final for the binding (found by a local review) - confirm READY with the register-read challenge after the settle step too, and judge the challenge by the re-armed ready word alone: the key the loader expects in DATA could collide with the word it returns there (found by Sashiko AI review) - return an SMDIO bus timeout during the challenge as the bus error it is; only an unserviced challenge is -ENXIO (found by Sashiko AI review) - drop the "firmware booted while draining" outcome of the drain's finish: the drained image's zero fill fails the loader's CRC gate, so any count outliving the window is a stuck loader (found by Sashiko AI review) - log a self-heal re-probe that cannot be scheduled (found by Sashiko AI review) - set WORK_STOPPED before waiting out a flash in .remove() and ->shutdown(), so the drain stops as early as possible (found by Sashiko AI review) - drop the rescue-mode disjunct from port_mdb_add() and port_mdb_del(): no user netdev exists in rescue mode to reach them (found by Sashiko AI review) - the final slice's verification window moves to the previous patch - name the power cycle in the probe-time handshake message and the devlink documentation without its path in the kernel-doc, since the next patch adds it (found by Sashiko AI review) - commit message: name every detection outcome and the mailbox resets, and the CRC mapping (found by Sashiko AI review) - comments: state the drain's bound as what it is, the settle step's classification as the policy it is, and every cause of -EIO in the file header (found by Sashiko AI review and a local review) v18: - a quiet firmware command, as the readiness poll issues, does not arm the CRC-error work: a probe that meets the loader mid-erase fails every poll's CRC check, which closed the conduit and warned on each of them; the CRC sites report -EBADMSG and mxl862xx_api_wrap() arms the work in one place - after a failed clause-45 wait, classify a status word that outlives the settle step as rescue only when it is the erase count of the session that died; any other value is a firmware that answered the reset without becoming ready, and probe fails with the wait error as it did before this patch (found by Sashiko AI review) - report the rescue-mode version as running only; the driver cannot tell what the flash holds (found by Sashiko AI review) - name the interrupted opening handshake in the probe-time log message, the only failure known at that point, and word the -EIO extack for every cause (found by Sashiko AI review) - port_mdb_add()/port_mdb_del(): rescue mode joins the flags under which a gated read counts as success, in the form of the previous patch, whose silent get_ethtool_stats() return covers rescue mode as well (found by Sashiko AI review) - kernel-doc: WORK_STOPPED also ends the drain and its reprobe hand-off; the file header names the -EIO state (found by Sashiko AI review) - commit message: describe the detection outcomes again (found by Sashiko AI review) v17: - bypass the firmware-version gate in mxl862xx_phylink_get_caps() in rescue mode, so a SerDes CPU port does not get an empty supported_interfaces mask and fail phylink_create(); the sibling mac_select_pcs() bypass was already there (found by Sashiko AI review) - extend the port_mdb_add()/port_mdb_del() flash-window tolerance to rescue mode as well (found by Sashiko AI review) - the @rescue_failed kernel-doc and the mxl862xx_setup_rescue() log message no longer prescribe a power cycle for every cause; the per-cause remedy is in the documentation (found by Sashiko AI review) v16: - drop the claim that the clause-45 API floods the log with CRC errors when no firmware answers, here and in the comments. The mailbox commands run into their timeouts instead, and testing the stuck-in-MCUboot paths produces no such message. What probing SB PDI first saves is the ten seconds of polling and the -ETIMEDOUT that ends probe - move the rescue-mode branch of mxl862xx_setup() into a function of its own, which brings its messages back inside 100 columns - state a fact in the -EBUSY extack of a running recovery, dropping the retry advice - trim the comment on mxl862xx_rescue_drain(), whose protocol detail is in the file header already, and order its declarations longest line first - treat a byte count that outlives the settle step as a busy loader rather than a running firmware, and wait out an erase from the dead session before draining, so a host that died during the loader's erase no longer fails probe with the -ETIMEDOUT this patch exists to avoid (found by Sashiko AI review) - poll the status register every 10 ms rather than every 50 us for the waits now measured in minutes - drop the loader's clean ready state along with the cached identity when a flash fails, so devlink dev info stops reporting 0.0.0, which means "ready to accept an image", for a loader left mid transfer (found by Sashiko AI review) - state facts in the extack for a failed recovery; the remedies, which differ per cause, are in the documentation (found by Sashiko AI review) - name -ECANCELED in the documented return sets that can produce it, and the opening handshake among the detection outcomes in the commit message (found by Sashiko AI review) v15: - classify a status register left in the download handshake as a loader needing a power cycle, rather than as a running firmware, which made probe fail with the CRC-error storm this patch avoids (found by Sashiko AI review) - give the loader one step to publish its next state when detection runs after a failed clause-45 wait, so the count of a chunk it is still programming is not read as a firmware status word (found by Sashiko AI review) - abort the drain polls as soon as teardown asks for it, instead of holding up unbind and shutdown for up to 17 s (found by Sashiko AI review) - pair the rescue_mode accesses with WRITE_ONCE()/READ_ONCE(), like the sibling rescue flags (found by Sashiko AI review) v14: - initialise the SerDes state once mxl862xx_wait_ready() has cached the firmware version, still before the rescue-mode early return, so PCS setup can depend on the running firmware v13: no changes v12: no changes v11: - schedule the post-drain re-probe with device_schedule_reprobe() too, instead of a driver-owned work item - a drain whose re-probe hand-off fails still marks recovery failed, so devlink does not keep promising a retry v10: - share the SB PDI timeouts with the flash path: one constant for the verify wait (15 s) and one for a single 1-byte mailbox step (2 s), the latter also replacing the separate detection timeout. The last-slice flush gets the sum of the write and verify budgets, since it cannot see the boundary between programming and verifying (found by Sashiko AI review) - report a reprobe hand-off that cannot be set up after a successful drain, instead of leaving devlink answering "retry shortly" for good for a loader sitting at a clean READY (found by Sashiko AI review) - drop heal_lock and mxl862xx_stop_work() with it: making the flag test and the queueing atomic was never the guarantee its comment claimed, and the reprobe now decides for itself whether it may still run (found by Sashiko AI review) - return -ENXIO rather than a propagated -ETIMEDOUT when the loader never re-arms READY for the register-read challenge, and correct the documented return sets of mxl862xx_rescue_mode_detect() and mxl862xx_rescue_drain_finish() (found by Sashiko AI review) - explain why STAT == 0 during a drain is unambiguous: by the r_remain == 0 rule the loader cannot be both inside the receive loop asking for a chunk and publishing a verdict (found by Sashiko AI review) - commit message: a running firmware is not "left untouched", the presence probe writes two mailbox scratch registers which are inert to it; an SB PDI window away from the OTP reset offsets also yields -ENODEV; and describe the -ENXIO outcome for a READY loader that never services the challenge (found by Sashiko AI review) v9: no changes v8: - never send END from the drain: the loader keeps the host's byte count in its status register while it programs a chunk, so a lingering count cannot be told from the "image rejected" verdict, and END written into the receive loop is consumed as a 15555-byte count and underflows the receive counter. Wait for the loader to ask for the next chunk or to return to its console loop instead, since it finalises on its own (found by Sashiko AI review) - initialise the SerDes state before the rescue-mode early return, so the window between a successful rescue-mode flash clearing rescue_mode and the reprobe cannot hand phylink a PCS with no ops and an uninitialised mutex (found by Sashiko AI review) - do not fail probe when the 1-byte slice-advance leaves the wedged loader somewhere other than asking for the next chunk: a download interrupted with exactly one byte outstanding completes on that byte, after which the loader verifies and returns to its console loop (found by Sashiko AI review) - report a failed drain and refuse further flashes with -EIO and an extack asking for a power cycle, instead of leaving devlink to answer "retry shortly" forever for a switch that never becomes ready (found by Sashiko AI review) - reset the mailbox before the presence probe: a download interrupted with the write latch armed made the scratch write land in switch memory instead, so detection returned -ENODEV for the very state it exists to recover (found by Sashiko AI review) - tell an SMDIO bus error apart from a loader failing the register-read challenge, and check the reset issued after it (found by Sashiko AI review) - reject DSA links before the rescue-mode shortcut, so an unsupported cascade topology fails probe in rescue mode too (found by Sashiko AI review) - serialise the self-heal's reprobe hand-off against teardown with a mutex (found by Sashiko AI review) - log the drain's progress, name its timeouts, and describe its real duration (found by Sashiko AI review) - WRITE_ONCE() the rescue_ready stores, document what orders rescue_mode, and correct the detection kernel-doc and the note on the OTP-configurable SB PDI register offsets (found by Sashiko AI review) v7: - queue the reprobe as a delayed work item from the background self-heal, following the previous patch's move off the reprobe kthread - report the rescue-mode firmware version under DEVLINK_INFO_VERSION_GENERIC_FW too - drop two redundant rescue-recovery log lines; the setup message ("switch in MCUboot with an interrupted download, recovering in background") already says it - return distinct errno from rescue_mode_detect() so an absent switch (-ENODEV), one strapped into flashless-download mode (-EOPNOTSUPP) and one that answers SB PDI READY but fails the register-read challenge, or wedges without draining (-ENXIO), are no longer all reported as -ENODEV v6: - after the background drain finalises the interrupted transfer, reprobe and let the probe-time detection re-classify the switch, so a valid image a last-moment interruption left bootable is picked up as running firmware; rescue_drain() no longer inspects or reports the outcome (its stale kernel-doc claiming a "return 1" case is gone) - poll the drain status register with read_poll_timeout() as well, which evaluates the condition once more after the deadline, matching the poll fix in the previous patch - treat the flashless-download loop (STAT 0xc33c) as an unsupported configuration and fail probe with -ENODEV, rather than advertising it as flashable when the console flash path cannot drive it v5: - detect the switch state from the value MCUboot publishes in the SB PDI STAT register (loader ready, wedged download, or running firmware), confirming a live console loader with a register-read challenge, instead of trusting a bare SMDIO scratch write - fail probe with -ENODEV over SB PDI when the switch does not respond at all -- absent, unpowered, or misdescribed in the device tree -- instead of letting the clause-45 API flood the log with CRC errors - drain a wedged interrupted download back to a clean ready state from a background work item so the multi-minute recovery never holds the devlink instance lock, and refuse devlink dev info and flash until it is ready - report the null firmware version as the stored version too, matching the running/stored reporting of the previous patch - do not report asic.id/asic.rev in rescue mode as the CHIP ID registers are unreadable without firmware; recovery tools match on the driver name and the "0.0.0" version instead (follows the numeric asic.id change in the previous patch) - move the devlink documentation into its own patch v4: - log a distinct diagnostic when rescue mode detection fails on an SMDIO bus error instead of silently treating it as "not in rescue mode" - clear the rescue_mode flag under the MDIO bus lock, following the flag write locking in the previous patch v3: - report the canonical null version "0.0.0" instead of "mcuboot-rescue" so that version-comparing update tools like fwupd offer any available release as an upgrade for recovery - check the rescue_mode flag under the MDIO bus lock, following the block_host/skip_teardown change in the previous patch v2: new patch, allowing recovery from a failed or interrupted update without having to use a special recovery OS image (Andrew Lunn) drivers/net/dsa/mxl862xx/mxl862xx-fw.c | 501 +++++++++++++++++++- drivers/net/dsa/mxl862xx/mxl862xx-fw.h | 3 + drivers/net/dsa/mxl862xx/mxl862xx-host.c | 73 +-- drivers/net/dsa/mxl862xx/mxl862xx-phylink.c | 9 +- drivers/net/dsa/mxl862xx/mxl862xx.c | 108 ++++- drivers/net/dsa/mxl862xx/mxl862xx.h | 25 +- 6 files changed, 663 insertions(+), 56 deletions(-) diff --git a/drivers/net/dsa/mxl862xx/mxl862xx-fw.c b/drivers/net/dsa/mxl862xx/mxl862xx-fw.c index eae7048707870..eb48fbf7c7115 100644 --- a/drivers/net/dsa/mxl862xx/mxl862xx-fw.c +++ b/drivers/net/dsa/mxl862xx/mxl862xx-fw.c @@ -29,9 +29,11 @@ * * STAT magics: * READY 0xc55c loader idle in the console loop (this driver) + * DL_RDY 0xc33c loader idle in the flashless loop * START 0xf48f host -> begin download session * ACK 0xf490 loader -> START acknowledged (START + 1) * END 0x3cc3 host -> finalise now (optional, see below) + * RDREG 0xe2c0 host -> register-read command (| index), see below * * Console flash path (STAT=0xc55c) - mxl862xx_flash_firmware(): * @@ -73,7 +75,41 @@ * - the loader leaves the count in STAT while it programs the chunk, so * a lingering count does not distinguish "busy" from "verdict"; * - STAT is a 16-bit register, so a slice holds at most 65535 bytes, - * which is what bounds MXL862XX_FW_BANK_SLICE. + * which is what bounds MXL862XX_FW_BANK_SLICE; + * - interrupted-download recovery feeds 1 byte at a time (see below). + * + * Interrupted-flash recovery (mxl862xx_rescue_drain): + * A host that dies mid-payload leaves the loader in the receive loop holding + * STAT=0. Feed single 1-byte chunks (one DATA word + STAT=1) until r_remain + * reaches 0; the loader then verifies the (now corrupt) image, publishes its + * verdict and comes back to READY by itself. END is never sent here: while + * r_remain is non-zero it would be consumed as a 15555-byte count, and a + * lingering STAT=1 cannot be told from a chunk still being programmed. + * + * Register-read challenge (non-destructive liveness proof): + * DATA := 0x7c23 (key); STAT := 0xe2c0|idx + * -> loader returns a runtime word in DATA and re-arms STAT=0xc55c. + * Only the re-arm counts, to prove a live mailbox in + * mxl862xx_rescue_mode_detect(); the word is loader BSS, not a chip id. + * + * The other STAT ready magic, 0xc33c, marks the loader's flashless + * chip-to-chip download mode (MxL86281S 16-port tier); this driver does not + * use it. + * + * Rescue lifecycle (devlink): probe runs mxl862xx_rescue_mode_detect(); a + * wedged loader is drained back to READY by a background self-heal + * (rescue_heal_work), so the long recovery never holds the devlink lock. + * devlink dev info exposes the fw version (the "flashable" signal) only once at + * READY; flash_update returns -EBUSY until then, -EIO for good once the + * loader cannot accept a download (a failed recovery, or a handshake no + * session can finish), and reprobes to WSP firmware on success. + * + * Notes: + * - Chip id/revision (0xc0d28884/88) are NOT reachable on this channel; they + * need the clause-45 MMD firmware mailbox, which is dead under MCUboot. + * Rescue identity is by SB PDI behaviour only (mxl862xx_rescue_mode_detect). + * - The SMDIO PHY address comes from the device tree; the 0xe1xx register + * offsets are the OTP reset defaults and the only layout supported here. */ #include <linux/crc32.h> @@ -106,8 +142,15 @@ /* SB PDI handshake magic (published/consumed via STAT) */ #define MXL862XX_SB_PDI_READY 0xc55c /* loader idle, console loop */ +#define MXL862XX_SB_PDI_DL_READY 0xc33c /* loader idle, flashless loop */ #define MXL862XX_SB_PDI_START 0xf48f #define MXL862XX_SB_PDI_END 0x3cc3 +#define MXL862XX_SB_PDI_RDREG 0xe2c0 /* register-read cmd (| index) */ +#define MXL862XX_SB_PDI_RDREG_MARK 0x7c23 /* key the loader expects in DATA */ + +/* Behavioural presence probe: two distinct 16-bit latches on ADDR/DATA. */ +#define MXL862XX_SB_PDI_PROBE_A 0x5a5a +#define MXL862XX_SB_PDI_PROBE_D 0xa5a5 /* Image verification verdict published in STAT once the receive loop ends */ #define MXL862XX_SB_PDI_VERIFY_OK 0 @@ -126,6 +169,11 @@ #define MXL862XX_FW_WRITE_TIMEOUT_MS 60000 /* Covers the loader's END wait, verification and the reset into READY */ #define MXL862XX_SB_PDI_VERIFY_MS 15000 +/* One loader mailbox step: program a 1-byte chunk or service a command */ +#define MXL862XX_SB_PDI_STEP_MS 2000 +/* STAT poll intervals: a mailbox step is quick, an erase is not */ +#define MXL862XX_SB_PDI_POLL_US 50 +#define MXL862XX_SB_PDI_SLOW_POLL_US 10000 /* Delays spent in full: the reboot into the new image, and the re-probe */ #define MXL862XX_FW_REBOOT_DELAY_MS 5000 @@ -225,6 +273,395 @@ static void mxl862xx_flash_notify(struct devlink *dl, const char *status, devlink_flash_update_status_notify(dl, status, NULL, done, total); } +/* Byte-count of each chunk fed to the loader during drain. It MUST be 1: the + * loader only lets us observe "counter == 0", never "counter < step", so any + * step > 1 can subtract past zero, underflow the 32-bit counter and wedge the + * loader for ~2^32 more bytes (a state only a power cycle clears). Stepping by + * 1 walks the counter through every value and is guaranteed to land on zero + * whatever its (possibly odd) start; the loader counts bytes, not words, and + * single-byte chunks are what the drain was tested with. + */ +#define MXL862XX_DRAIN_CHUNK_BYTES 1 + +/* Log the drain's progress every so many bytes; it can run for a long time */ +#define MXL862XX_DRAIN_LOG_BYTES (128 * 1024) + +/* Wait for the loader to ask for the next chunk (STAT 0) or to come back to its + * command loop (STAT READY), and return the STAT value either way, or + * -ECANCELED once teardown asks the caller to stop. On timeout the value is + * whatever STAT still holds, which carries no further information: the + * loader keeps the count we wrote visible while it programs the chunk, and that + * is the same value it publishes as the "image rejected" verdict once the + * counter reaches zero. + * + * STAT 0 is unambiguous here even though it is also the "image verified" + * verdict: by the r_remain == 0 rule the loader leaves the receive loop the + * moment the counter reaches zero, so it is never both inside the loop asking + * for a chunk and publishing a verdict. Once it has left, the next STAT write + * is a command rather than a count, so feeding one more chunk after a verdict + * cannot underflow anything either. + */ +static int mxl862xx_sb_pdi_poll_drain(struct mxl862xx_priv *priv, + unsigned long sleep_us, + unsigned long timeout_ms) +{ + int val; + + read_poll_timeout(mxl862xx_smdio_read, val, + val < 0 || (u16)val == MXL862XX_SB_PDI_READY || + (u16)val == 0 || + test_bit(MXL862XX_FLAG_WORK_STOPPED, &priv->flags), + sleep_us, timeout_ms * 1000, false, + priv, MXL862XX_SB_PDI_STAT); + if (val < 0) + return val; + if (test_bit(MXL862XX_FLAG_WORK_STOPPED, &priv->flags)) + return -ECANCELED; + return (u16)val; +} + +/* The loader is not asking for a chunk: it may still be programming the last + * one, or the counter has reached zero and it is verifying the image and + * resetting into READY. Before the first chunk it may also still be erasing + * for the session that died, which no verify window covers. Wait that out: + * STAT cannot tell the cases apart, and guessing would mean writing END into a + * live receive loop. The drained image never boots, since its zero fill fails + * the loader's CRC gate, so a count outliving the window is a loader that has + * stopped servicing the mailbox. + * + * Return: 0 once the loader is back at READY, -EAGAIN if it asks for another + * chunk after all, -EIO for a loader still holding a count when the window + * expires, -ECANCELED on teardown, or an SMDIO bus error. + */ +static int mxl862xx_rescue_drain_finish(struct mxl862xx_priv *priv, u32 chunk) +{ + struct device *dev = &priv->mdiodev->dev; + int stat; + + if (chunk) + stat = mxl862xx_sb_pdi_poll_drain(priv, MXL862XX_SB_PDI_POLL_US, + MXL862XX_SB_PDI_VERIFY_MS); + else + stat = mxl862xx_sb_pdi_poll_drain(priv, + MXL862XX_SB_PDI_SLOW_POLL_US, + MXL862XX_FW_ERASE_TIMEOUT_MS); + if (stat < 0) + return stat; + if (stat == MXL862XX_SB_PDI_READY) + return 0; + if (!stat) + return -EAGAIN; + + if (chunk) + dev_err(dev, + "flash: loader stuck after %u chunks, power cycle it\n", + chunk); + else + dev_err(dev, "flash: loader still busy after the erase window\n"); + + return -EIO; +} + +/* Walk the loader's receive counter to zero (see the header): the image size + * died with the host, and a chunk larger than what is outstanding underflows + * the counter, so only single bytes are safe. Tens of minutes for a multi-MiB + * remainder. Returns 0 once the loader has left the receive loop, <0 on error; + * a counter an earlier oversized chunk underflowed needs a power cycle. + */ +static int mxl862xx_rescue_drain(struct mxl862xx_priv *priv) +{ + /* Bound: 32 MiB in single-byte chunks, many times the largest image. */ + u32 max_chunks = (32u << 20) / MXL862XX_DRAIN_CHUNK_BYTES; + struct device *dev = &priv->mdiodev->dev; + u32 chunk = 0; + int ret, stat; + + while (chunk < max_chunks) { + /* Teardown can interrupt this long drain. */ + if (test_bit(MXL862XX_FLAG_WORK_STOPPED, &priv->flags)) + return -ECANCELED; + + stat = mxl862xx_sb_pdi_poll_drain(priv, MXL862XX_SB_PDI_POLL_US, + MXL862XX_SB_PDI_STEP_MS); + if (stat < 0) + return stat; + if (stat == MXL862XX_SB_PDI_READY) + return 0; + + if (stat) { + ret = mxl862xx_rescue_drain_finish(priv, chunk); + if (ret != -EAGAIN) + return ret; + } + + /* Feed one zero byte; reset cleared the write latch. */ + ret = mxl862xx_smdio_write(priv, MXL862XX_SB_PDI_CTRL, + MXL862XX_SB_PDI_CTRL_WR); + if (ret < 0) + return ret; + ret = mxl862xx_smdio_write(priv, MXL862XX_SB_PDI_DATA, 0x0000); + if (ret < 0) + return ret; + ret = mxl862xx_sb_pdi_reset(priv); + if (ret < 0) + return ret; + ret = mxl862xx_smdio_write(priv, MXL862XX_SB_PDI_STAT, + MXL862XX_DRAIN_CHUNK_BYTES); + if (ret < 0) + return ret; + chunk++; + if (!(chunk % MXL862XX_DRAIN_LOG_BYTES)) + dev_info(dev, "flash: drained %u KiB so far\n", + chunk / 1024); + cond_resched(); + } + + dev_err(dev, + "flash: interrupted download did not drain after %u chunks\n", + chunk); + + return -ETIMEDOUT; +} + +/* Background self-heal: drain a wedged download off the devlink flash path, so + * the long recovery never holds the devlink lock. Scheduled from probe; + * reprobes on success so the probe-time detection re-classifies the switch. + */ +void mxl862xx_rescue_heal_work_fn(struct work_struct *work) +{ + struct mxl862xx_priv *priv = + container_of(work, struct mxl862xx_priv, rescue_heal_work); + struct device *dev = &priv->mdiodev->dev; + int ret; + + ret = mxl862xx_rescue_drain(priv); + if (ret == -ECANCELED) + return; + if (ret) { + /* Nothing retries this, so say so: rescue_ready stays clear + * and devlink dev flash reports why it refuses. + */ + dev_err(dev, "flash: download recovery failed: %pe\n", + ERR_PTR(ret)); + WRITE_ONCE(priv->rescue_failed, true); + return; + } + + /* The interrupted transfer is finalised; reprobe so the probe-time + * detection brings the driver up flashable, with the loader at READY. + * The core drops the re-probe on its own if the device is unbound + * first; the flag test only avoids scheduling one certain to be + * dropped. A failed hand-off leaves nothing to reclassify the switch, + * so recovery is marked failed rather than promising a retry that + * cannot succeed. + */ + if (test_bit(MXL862XX_FLAG_WORK_STOPPED, &priv->flags)) + return; + + /* -EINVAL is a device being deleted, whose teardown ends this work. */ + ret = device_schedule_reprobe(dev, MXL862XX_FW_REPROBE_DELAY_MS); + if (ret && ret != -EINVAL) { + dev_err(dev, + "flash: re-probe could not be scheduled (%pe); unbind and rebind to reinitialise\n", + ERR_PTR(ret)); + WRITE_ONCE(priv->rescue_failed, true); + } +} + +/* Prove a live console loader behind READY: the register-read command, keyed + * by the word in DATA, is serviced by re-arming READY, which nothing but the + * loader's command loop does. The reset afterwards clears the word it leaves + * in DATA. + */ +static int mxl862xx_sb_pdi_challenge(struct mxl862xx_priv *priv) +{ + int ret, err, val; + + ret = mxl862xx_smdio_write(priv, MXL862XX_SB_PDI_DATA, + MXL862XX_SB_PDI_RDREG_MARK); + if (ret < 0) + return ret; + ret = mxl862xx_smdio_write(priv, MXL862XX_SB_PDI_STAT, + MXL862XX_SB_PDI_RDREG); + if (ret < 0) + return ret; + + ret = read_poll_timeout(mxl862xx_smdio_read, val, + val < 0 || (u16)val == MXL862XX_SB_PDI_READY, + MXL862XX_SB_PDI_SLOW_POLL_US, + MXL862XX_SB_PDI_STEP_MS * 1000, false, + priv, MXL862XX_SB_PDI_STAT); + err = mxl862xx_sb_pdi_reset(priv); + if (val < 0) + return val; + if (err < 0) + return err; + if (ret) + return -ENXIO; + + return 0; +} + +/* Detect MCUboot rescue mode over clause-22 SMDIO alone, so the caller can rule + * the loader out before any C45 API request (which only runs into its timeouts + * when no WSP firmware answers). A scratch write to ADDR/DATA must latch or the + * chip is absent (-ENODEV); the mailbox is reset first, or a transfer + * interrupted with CTRL=WR would take that write as a payload word instead of + * latching it. STAT then classifies the state, poked destructively only when 0, + * the one value a running firmware never holds: + * + * - 0xc33c: flashless loop; recognised but not supported here. + * - 0xc55c: console loop, if the register-read challenge is serviced. + * - 0xf48f/0xf490: a download handshake nobody can finish; rescue, but only + * a power cycle gets the loader out of it. + * - other non-zero: running firmware, left unpoked. With @settle the loader + * gets one step to publish 0 or READY first; a count outliving that is + * taken for rescue only when it is the erase of a session that died + * (header length + 1), anything else for a firmware that never became + * ready. + * - 0: wedged receive loop; the 1-byte slice-advance then says whether it + * still needs draining or has just finished. + * + * The scratch write reaches a running firmware too, but lands in mailbox + * registers it does not read, so it is inert there. + * + * Return: MXL862XX_IN_RESCUE, MXL862XX_NOT_RESCUE, -ENODEV when the scratch + * write does not latch, which is a switch that does not answer at all or one + * whose SB PDI window is not at the offsets above, -EOPNOTSUPP for the + * flashless loop, -ENXIO for a READY loader whose mailbox fails the challenge, + * -ECANCELED when teardown interrupts a poll, or an SMDIO bus error. + */ +int mxl862xx_rescue_mode_detect(struct mxl862xx_priv *priv, bool settle) +{ + int stat, ret, rb, a, d; + + /* rescue_ready gates flashing; a wedged loader needs the drain first. */ + WRITE_ONCE(priv->rescue_ready, false); + + ret = mxl862xx_sb_pdi_reset(priv); + if (ret < 0) + return ret; + + /* Presence: a live chip latches the scratch write, an absent one floats. */ + a = mxl862xx_smdio_write(priv, MXL862XX_SB_PDI_ADDR, + MXL862XX_SB_PDI_PROBE_A); + if (a < 0) + return a; + d = mxl862xx_smdio_write(priv, MXL862XX_SB_PDI_DATA, + MXL862XX_SB_PDI_PROBE_D); + if (d < 0) + return d; + a = mxl862xx_smdio_read(priv, MXL862XX_SB_PDI_ADDR); + if (a < 0) + return a; + d = mxl862xx_smdio_read(priv, MXL862XX_SB_PDI_DATA); + if (d < 0) + return d; + if ((u16)a != MXL862XX_SB_PDI_PROBE_A || + (u16)d != MXL862XX_SB_PDI_PROBE_D) + return -ENODEV; + + ret = mxl862xx_sb_pdi_reset(priv); + if (ret < 0) + return ret; + + stat = mxl862xx_smdio_read(priv, MXL862XX_SB_PDI_STAT); + if (stat < 0) + return stat; + + /* Flashless-download loop (MxL86281S tier): this driver does not + * support it -- the console flash path expects READY. Treat it as an + * unusable configuration, like any other unsupported state. + */ + if ((u16)stat == MXL862XX_SB_PDI_DL_READY) + return -EOPNOTSUPP; + + /* Console loop at READY: confirm the live mailbox with the register-read + * challenge. A firmware publishing 0xc55c as its status word looks the + * same until then, and flashing one would be far worse than refusing + * to bind, so an unserviced challenge is unusable (-ENXIO). + */ + if ((u16)stat == MXL862XX_SB_PDI_READY) { + ret = mxl862xx_sb_pdi_challenge(priv); + if (ret < 0) + return ret; + WRITE_ONCE(priv->rescue_ready, true); + return MXL862XX_IN_RESCUE; + } + + /* The download handshake lives in STAT too and outlives a mailbox + * reset, so an aborted transfer leaves the loader waiting for a + * header no later session can supply: only a power cycle clears it. + */ + if ((u16)stat == MXL862XX_SB_PDI_START || + (u16)stat == MXL862XX_SB_PDI_START + 1) { + WRITE_ONCE(priv->rescue_failed, true); + return MXL862XX_IN_RESCUE; + } + + /* Any other non-zero value is a running firmware, not a loader, but + * the loader also holds the count of a chunk it is programming or + * erasing for, so let a caller whose clause-45 wait has failed give it + * a step for the next state. A count that outlives the step is taken + * for rescue only when it is the erase count of a session that died; + * any other is taken for a firmware that answered the reset without + * becoming ready, since a status word of that firmware could hold any + * value. + */ + if (stat) { + if (!settle) + return MXL862XX_NOT_RESCUE; + + stat = mxl862xx_sb_pdi_poll_drain(priv, MXL862XX_SB_PDI_POLL_US, + MXL862XX_SB_PDI_STEP_MS); + if (stat < 0) + return stat; + if (stat == MXL862XX_SB_PDI_READY) { + ret = mxl862xx_sb_pdi_challenge(priv); + if (ret < 0) + return ret; + WRITE_ONCE(priv->rescue_ready, true); + return MXL862XX_IN_RESCUE; + } + if (stat == MXL862XX_FW_HDR_SIZE + 1) + return MXL862XX_IN_RESCUE; + if (stat) + return MXL862XX_NOT_RESCUE; + } + + /* STAT == 0: a wedged receive loop takes a 1-byte slice-advance (feed + * one DATA word first, like a drain chunk) and asks for the next chunk + * by publishing 0 again. Had that byte been the last one outstanding, + * the loader leaves the loop instead and returns to READY, having + * consumed the advance -- proof enough of a live mailbox to skip the + * challenge. Anything else means it is still working on it. All three + * are rescue, so this never fails probe; only the drain does. + */ + ret = mxl862xx_smdio_write(priv, MXL862XX_SB_PDI_CTRL, + MXL862XX_SB_PDI_CTRL_WR); + if (ret < 0) + return ret; + ret = mxl862xx_smdio_write(priv, MXL862XX_SB_PDI_DATA, 0x0000); + if (ret < 0) + return ret; + ret = mxl862xx_sb_pdi_reset(priv); + if (ret < 0) + return ret; + ret = mxl862xx_smdio_write(priv, MXL862XX_SB_PDI_STAT, + MXL862XX_DRAIN_CHUNK_BYTES); + if (ret < 0) + return ret; + + rb = mxl862xx_sb_pdi_poll_drain(priv, MXL862XX_SB_PDI_POLL_US, + MXL862XX_SB_PDI_STEP_MS); + if (rb < 0) + return rb; + if (rb == MXL862XX_SB_PDI_READY) + WRITE_ONCE(priv->rescue_ready, true); + + return MXL862XX_IN_RESCUE; +} + /* MCUboot firmware image header */ struct mxl862xx_fw_hdr { __le32 image_type; @@ -300,13 +737,15 @@ static int mxl862xx_flash_firmware(struct mxl862xx_priv *priv, int ret, val, i; /* Step 1: reboot the firmware into MCUboot rescue mode */ - ret = mxl862xx_api_wrap(priv, SYS_MISC_FW_UPDATE, NULL, 0, - false, false); - if (ret) { - dev_err(&priv->mdiodev->dev, - "flash: FW_UPDATE command failed: %pe\n", - ERR_PTR(ret)); - return ret; + if (!READ_ONCE(priv->rescue_mode)) { + ret = mxl862xx_api_wrap(priv, SYS_MISC_FW_UPDATE, NULL, 0, + false, false); + if (ret) { + dev_err(&priv->mdiodev->dev, + "flash: FW_UPDATE command failed: %pe\n", + ERR_PTR(ret)); + return ret; + } } /* Step 2: wait for bootloader ready */ @@ -504,6 +943,22 @@ int mxl862xx_devlink_info_get(struct dsa_switch *ds, char buf[16]; int ret; + /* No chip-id/revision in MCUboot (needs the firmware MMD mailbox). The + * fw version doubles as the "ready to flash" signal: report it only + * once the loader is at a clean READY, nothing while still draining, + * and as running only, since what the flash holds is unknown here. + */ + if (READ_ONCE(priv->rescue_mode)) { + if (!READ_ONCE(priv->rescue_ready)) + return 0; + + snprintf(buf, sizeof(buf), "%u.%u.%u", + priv->fw_version.major, priv->fw_version.minor, + priv->fw_version.revision); + return devlink_info_version_running_put(req, + DEVLINK_INFO_VERSION_GENERIC_FW, buf); + } + /* A 0 part number means the CHIP ID read failed, the part is unfused * or a flash failed; omit it rather than publish a bogus "0000" that * fwupd would match firmware against, it then falls back to the @@ -585,9 +1040,28 @@ int mxl862xx_devlink_flash_update(struct dsa_switch *ds, return ret; } - dev_info(ds->dev, "flash: running firmware %u.%u.%u\n", - priv->fw_version.major, priv->fw_version.minor, - priv->fw_version.revision); + /* Refuse to flash while the background self-heal is still draining, and + * for good once it has given up on the loader. + */ + if (READ_ONCE(priv->rescue_failed)) { + NL_SET_ERR_MSG_MOD(extack, + "switch is not flashable from this binding"); + return -EIO; + } + + if (READ_ONCE(priv->rescue_mode) && !READ_ONCE(priv->rescue_ready)) { + NL_SET_ERR_MSG_MOD(extack, + "switch is recovering an interrupted download"); + return -EBUSY; + } + + if (READ_ONCE(priv->rescue_mode)) + dev_info(ds->dev, + "flash: flashing switch via MCUboot rescue mode\n"); + else + dev_info(ds->dev, "flash: running firmware %u.%u.%u\n", + priv->fw_version.major, priv->fw_version.minor, + priv->fw_version.revision); /* Close ports while the firmware is still alive so the DSA core's * MDB/FDB tracking is drained, and detach user ports so userspace @@ -638,6 +1112,7 @@ int mxl862xx_devlink_flash_update(struct dsa_switch *ds, * readiness poll below read the freshly booted firmware. */ priv->flash_owner = current; + WRITE_ONCE(priv->rescue_mode, false); mutex_unlock(&priv->mdiodev->bus->mdio_lock); /* Refresh the cached versions so the flash update only @@ -654,11 +1129,13 @@ int mxl862xx_devlink_flash_update(struct dsa_switch *ds, if (ret) { /* The loader may hold an erased or partly written image; drop * the cached identity so devlink dev info stops reporting the - * pre-flash version until the reprobe re-reads the truth. + * pre-flash version until the reprobe re-reads the truth, and + * with it the loader's clean READY state. */ memset(&priv->fw_version, 0, sizeof(priv->fw_version)); priv->asic_id = 0; priv->asic_rev = 0; + WRITE_ONCE(priv->rescue_ready, false); } mutex_lock_nested(&priv->mdiodev->bus->mdio_lock, MDIO_MUTEX_NESTED); diff --git a/drivers/net/dsa/mxl862xx/mxl862xx-fw.h b/drivers/net/dsa/mxl862xx/mxl862xx-fw.h index 15ed3a46bcfe2..02e5a627e9471 100644 --- a/drivers/net/dsa/mxl862xx/mxl862xx-fw.h +++ b/drivers/net/dsa/mxl862xx/mxl862xx-fw.h @@ -6,7 +6,10 @@ #include <net/dsa.h> struct mxl862xx_priv; +struct work_struct; +int mxl862xx_rescue_mode_detect(struct mxl862xx_priv *priv, bool settle); +void mxl862xx_rescue_heal_work_fn(struct work_struct *work); int mxl862xx_devlink_info_get(struct dsa_switch *ds, struct devlink_info_req *req, struct netlink_ext_ack *extack); diff --git a/drivers/net/dsa/mxl862xx/mxl862xx-host.c b/drivers/net/dsa/mxl862xx/mxl862xx-host.c index b229c4512b82c..744bbb8d6a24e 100644 --- a/drivers/net/dsa/mxl862xx/mxl862xx-host.c +++ b/drivers/net/dsa/mxl862xx/mxl862xx-host.c @@ -17,6 +17,7 @@ #include <net/dsa.h> #include "mxl862xx.h" #include "mxl862xx-cmd.h" +#include "mxl862xx-fw.h" #include "mxl862xx-host.h" #define CTRL_BUSY_MASK BIT(15) @@ -55,9 +56,14 @@ static void mxl862xx_crc_err_work_fn(struct work_struct *work) clear_bit(MXL862XX_FLAG_CRC_ERR, &priv->flags); } -/* Firmware CRC error codes (outside normal Zephyr errno range). */ +/* The firmware reports a CRC-6 mismatch on ctrl/len_ret and a CRC-16 mismatch + * on the data payload with codes outside the Zephyr errno range. The host's + * own verdict lies outside the 11-bit result range, so no firmware result + * can be mistaken for it. + */ #define MXL862XX_FW_CRC6_ERR (-1024) #define MXL862XX_FW_CRC16_ERR (-1023) +#define MXL862XX_HOST_CRC_ERR (-1025) /* 3GPP CRC-6 lookup table (polynomial 0x6F). * Matches the firmware's default CRC-6 implementation. @@ -216,7 +222,9 @@ static int mxl862xx_busy_wait(struct mxl862xx_priv *priv) /* Issue a firmware command with CRC-6 protection on the ctrl and len_ret * registers, wait for completion, and verify the response CRC-6. * - * Return: firmware result value (>= 0) on success, or negative errno. + * Return: firmware result value (>= 0) on success, a negative firmware + * errno or CRC code, %MXL862XX_HOST_CRC_ERR for a response failing its + * CRC-6 check here, or a negative bus errno. */ static int mxl862xx_issue_cmd(struct mxl862xx_priv *priv, u16 cmd, u16 len) { @@ -250,15 +258,18 @@ static int mxl862xx_issue_cmd(struct mxl862xx_priv *priv, u16 cmd, u16 len) len_enc = ret; ret = mxl862xx_crc6_verify(ctrl_enc, len_enc, &fw_result); - if (ret) { - if (!test_and_set_bit(MXL862XX_FLAG_CRC_ERR, &priv->flags)) - schedule_work(&priv->crc_err_work); - return -EIO; - } + if (ret) + return MXL862XX_HOST_CRC_ERR; return fw_result; } +static bool mxl862xx_crc_failed(int ret) +{ + return ret == MXL862XX_HOST_CRC_ERR || ret == MXL862XX_FW_CRC6_ERR || + ret == MXL862XX_FW_CRC16_ERR; +} + static int mxl862xx_set_data(struct mxl862xx_priv *priv, u16 words) { u16 cmd; @@ -305,26 +316,20 @@ static int mxl862xx_send_cmd(struct mxl862xx_priv *priv, u16 cmd, u16 size, ret = mxl862xx_issue_cmd(priv, cmd, size); - /* Handle errors returned by the firmware as -EIO. + /* Handle errors returned by the firmware as -EIO; a CRC code passes + * through for mxl862xx_api_wrap() to act on. * The firmware is based on Zephyr OS and uses the errors as * defined in errno.h of Zephyr OS. See * https://github.com/zephyrproject-rtos/zephyr/blob/v3.7.0/lib/libc/minimal/include/errno.h - * - * The firmware signals CRC validation failures with dedicated - * error codes outside the normal Zephyr errno range: - * -1024: CRC-6 mismatch on ctrl/len_ret registers - * -1023: CRC-16 mismatch on data payload */ - if (ret < 0) { - if ((ret == MXL862XX_FW_CRC6_ERR || - ret == MXL862XX_FW_CRC16_ERR) && - !test_and_set_bit(MXL862XX_FLAG_CRC_ERR, &priv->flags)) - schedule_work(&priv->crc_err_work); - if (!quiet) - dev_err(&priv->mdiodev->dev, - "CMD %04x returned error %d\n", cmd, ret); - return -EIO; - } + if (ret == MXL862XX_HOST_CRC_ERR && !quiet) + dev_err(&priv->mdiodev->dev, + "CMD %04x response failed its CRC check\n", cmd); + else if (ret < 0 && !quiet) + dev_err(&priv->mdiodev->dev, + "CMD %04x returned error %d\n", cmd, ret); + if (ret < 0) + return mxl862xx_crc_failed(ret) ? ret : -EIO; return ret; } @@ -334,7 +339,7 @@ bool mxl862xx_api_gated(struct mxl862xx_priv *priv) bool gated; mutex_lock_nested(&priv->mdiodev->bus->mdio_lock, MDIO_MUTEX_NESTED); - gated = priv->block_host || priv->skip_teardown; + gated = priv->block_host || priv->skip_teardown || priv->rescue_mode; mutex_unlock(&priv->mdiodev->bus->mdio_lock); return gated; @@ -358,6 +363,11 @@ int mxl862xx_api_wrap(struct mxl862xx_priv *priv, u16 cmd, void *_data, goto out; } + if (priv->rescue_mode) { + ret = -ENODEV; + goto out; + } + /* During the post-flash readiness poll block_host stays set, but the * flash path's own firmware version reads must reach the new image; * host writes stay blocked so stale resource IDs cannot corrupt it. @@ -491,9 +501,7 @@ int mxl862xx_api_wrap(struct mxl862xx_priv *priv, u16 cmd, void *_data, } if (crc16(0xffff, (const u8 *)data, size) != crc) { - if (!test_and_set_bit(MXL862XX_FLAG_CRC_ERR, &priv->flags)) - schedule_work(&priv->crc_err_work); - ret = -EIO; + ret = MXL862XX_HOST_CRC_ERR; goto out; } @@ -503,6 +511,15 @@ int mxl862xx_api_wrap(struct mxl862xx_priv *priv, u16 cmd, void *_data, dev_dbg(&priv->mdiodev->dev, "RET %d DATA %*ph\n", ret, size, data); out: + /* A quiet command is expected to go unanswered by a switch still + * booting or sitting in its loader, so it does not arm the shutdown. + */ + if (mxl862xx_crc_failed(ret)) { + if (!quiet && + !test_and_set_bit(MXL862XX_FLAG_CRC_ERR, &priv->flags)) + schedule_work(&priv->crc_err_work); + ret = -EIO; + } mutex_unlock(&priv->mdiodev->bus->mdio_lock); return ret; @@ -570,9 +587,11 @@ int mxl862xx_smdio_write(struct mxl862xx_priv *priv, u32 addr, u16 val) void mxl862xx_host_init(struct mxl862xx_priv *priv) { INIT_WORK(&priv->crc_err_work, mxl862xx_crc_err_work_fn); + INIT_WORK(&priv->rescue_heal_work, mxl862xx_rescue_heal_work_fn); } void mxl862xx_host_shutdown(struct mxl862xx_priv *priv) { cancel_work_sync(&priv->crc_err_work); + cancel_work_sync(&priv->rescue_heal_work); } diff --git a/drivers/net/dsa/mxl862xx/mxl862xx-phylink.c b/drivers/net/dsa/mxl862xx/mxl862xx-phylink.c index b689652aa9b92..df77bbf108d5e 100644 --- a/drivers/net/dsa/mxl862xx/mxl862xx-phylink.c +++ b/drivers/net/dsa/mxl862xx/mxl862xx-phylink.c @@ -47,7 +47,12 @@ void mxl862xx_phylink_get_caps(struct dsa_switch *ds, int port, fallthrough; case 10 ... 12: case 14 ... 16: - if (!MXL862XX_FW_VER_MIN(priv, 1, 0, 84)) + /* Rescue mode has no firmware version, so bypass the gate and + * advertise the full set; a CPU port on a quad sub-interface + * would otherwise get an empty mask and fail phylink_create(). + */ + if (!READ_ONCE(priv->rescue_mode) && + !MXL862XX_FW_VER_MIN(priv, 1, 0, 84)) break; __set_bit(PHY_INTERFACE_MODE_QSGMII, config->supported_interfaces); __set_bit(PHY_INTERFACE_MODE_10G_QXGMII, config->supported_interfaces); @@ -406,6 +411,8 @@ mxl862xx_phylink_mac_select_pcs(struct phylink_config *config, switch (port) { case 9 ... 16: + if (READ_ONCE(priv->rescue_mode)) + return NULL; if (!MXL862XX_FW_VER_MIN(priv, 1, 0, 84)) { dev_warn_once(dp->ds->dev, "SerDes PCS unsupported on old firmware.\n"); diff --git a/drivers/net/dsa/mxl862xx/mxl862xx.c b/drivers/net/dsa/mxl862xx/mxl862xx.c index e6f710c676e65..9097b0c559256 100644 --- a/drivers/net/dsa/mxl862xx/mxl862xx.c +++ b/drivers/net/dsa/mxl862xx/mxl862xx.c @@ -670,27 +670,85 @@ static void mxl862xx_free_bridge(struct dsa_switch *ds, priv->bridges[bridge->num] = 0; } +static void mxl862xx_setup_rescue(struct dsa_switch *ds) +{ + struct mxl862xx_priv *priv = ds->priv; + + if (priv->rescue_ready) { + dev_warn(ds->dev, + "switch in MCUboot rescue mode, use devlink to flash new firmware\n"); + return; + } + + if (priv->rescue_failed) { + dev_warn(ds->dev, + "switch in MCUboot with an unfinishable download handshake, only a power cycle clears it\n"); + return; + } + + /* Drain the wedged download in the background so it never holds the + * devlink lock; info and flash become available once ready. + */ + dev_warn(ds->dev, + "switch in MCUboot with an interrupted download, recovering in background\n"); + queue_work(system_long_wq, &priv->rescue_heal_work); +} + static int mxl862xx_setup(struct dsa_switch *ds) { struct mxl862xx_priv *priv = ds->priv; int n_user_ports = 0, max_vlans; int ingress_finals, vid_rules; struct dsa_port *dp; - int ret, i; + int ret, i, rescue; - ret = mxl862xx_reset(priv); - if (ret) - return ret; + /* Detect the loader over SB PDI first: it needs no firmware, unlike the + * C45 API (mxl862xx_reset/wait_ready), which spends its whole 10 s + * window on a mailbox nobody answers. Touch C45 only once rescue is + * ruled out. + */ + rescue = mxl862xx_rescue_mode_detect(priv, false); + if (rescue < 0) { + dev_err(ds->dev, "switch in an unusable state: %pe\n", + ERR_PTR(rescue)); + return rescue; + } - ret = mxl862xx_wait_ready(ds); - if (ret) - return ret; + if (rescue == MXL862XX_NOT_RESCUE) { + ret = mxl862xx_reset(priv); + if (ret) + return ret; + ret = mxl862xx_wait_ready(ds); + if (ret) { + /* the reset may only now have triggered rescue mode */ + rescue = mxl862xx_rescue_mode_detect(priv, true); + if (rescue < 0) { + dev_err(ds->dev, + "switch in an unusable state after reset: %pe\n", + ERR_PTR(rescue)); + return rescue; + } + if (rescue == MXL862XX_NOT_RESCUE) + return ret; + } + } + + priv->rescue_mode = rescue; + + /* Software-only SerDes state, needed before anything can reach phylink, + * including a rescue-mode flash clearing rescue_mode ahead of reprobe. + */ mutex_init(&priv->serdes_lock); for (i = 0; i < ARRAY_SIZE(priv->serdes_ports); i++) mxl862xx_setup_pcs(priv, &priv->serdes_ports[i], i + MXL862XX_FIRST_SERDES_PORT); + if (priv->rescue_mode) { + mxl862xx_setup_rescue(ds); + return 0; + } + /* Calculate Extended VLAN block sizes. * With VLAN Filter handling VID membership checks: * Ingress: only final catchall rules (PVID insertion, 802.1Q @@ -781,11 +839,21 @@ static int mxl862xx_port_state(struct dsa_switch *ds, int port, bool enable) static int mxl862xx_port_enable(struct dsa_switch *ds, int port, struct phy_device *phydev) { + struct mxl862xx_priv *priv = ds->priv; + + if (READ_ONCE(priv->rescue_mode)) + return 0; + return mxl862xx_port_state(ds, port, true); } static void mxl862xx_port_disable(struct dsa_switch *ds, int port) { + struct mxl862xx_priv *priv = ds->priv; + + if (READ_ONCE(priv->rescue_mode)) + return; + if (mxl862xx_port_state(ds, port, false)) dev_err(ds->dev, "failed to disable port %d\n", port); } @@ -1403,6 +1471,17 @@ static int mxl862xx_port_setup(struct dsa_switch *ds, int port) bool is_cpu_port = dsa_port_is_cpu(dp); int ret; + if (dsa_port_is_dsa(dp)) { + dev_err(ds->dev, "port %d: DSA links not supported\n", port); + return -EOPNOTSUPP; + } + + /* DSA reinits failed user ports as unused; shared ports must + * succeed for the tree to register. + */ + if (READ_ONCE(priv->rescue_mode)) + return dsa_port_is_user(dp) ? -ENODEV : 0; + ret = mxl862xx_port_state(ds, port, false); if (ret) return ret; @@ -1412,11 +1491,6 @@ static int mxl862xx_port_setup(struct dsa_switch *ds, int port) if (dsa_port_is_unused(dp)) return 0; - if (dsa_port_is_dsa(dp)) { - dev_err(ds->dev, "port %d: DSA links not supported\n", port); - return -EOPNOTSUPP; - } - ret = mxl862xx_configure_sp_tag_proto(ds, port, is_cpu_port); if (ret) return ret; @@ -1706,6 +1780,9 @@ static void mxl862xx_port_stp_state_set(struct dsa_switch *ds, int port, struct mxl862xx_priv *priv = ds->priv; int ret; + if (READ_ONCE(priv->rescue_mode)) + return; + switch (state) { case BR_STATE_DISABLED: param.port_state = cpu_to_le32(MXL862XX_STP_PORT_STATE_DISABLE); @@ -2234,14 +2311,14 @@ static void mxl862xx_remove(struct mdio_device *mdiodev) priv = ds->priv; + set_bit(MXL862XX_FLAG_WORK_STOPPED, &priv->flags); + /* Wait out a flash in flight and bar a new one before the DSA core * frees the user netdevs; the devlink instance lock does not cover * that free, which dsa_unregister_switch() reaches first. */ mxl862xx_flash_shutdown(ds); - set_bit(MXL862XX_FLAG_WORK_STOPPED, &priv->flags); - dsa_unregister_switch(ds); mxl862xx_host_shutdown(priv); @@ -2266,11 +2343,12 @@ static void mxl862xx_shutdown(struct mdio_device *mdiodev) priv = ds->priv; + set_bit(MXL862XX_FLAG_WORK_STOPPED, &priv->flags); + mxl862xx_flash_shutdown(ds); dsa_switch_shutdown(ds); - set_bit(MXL862XX_FLAG_WORK_STOPPED, &priv->flags); disable_delayed_work_sync(&priv->stats_work); mxl862xx_host_shutdown(priv); diff --git a/drivers/net/dsa/mxl862xx/mxl862xx.h b/drivers/net/dsa/mxl862xx/mxl862xx.h index 7d6bee9fa33d7..98b3afdc5ef1f 100644 --- a/drivers/net/dsa/mxl862xx/mxl862xx.h +++ b/drivers/net/dsa/mxl862xx/mxl862xx.h @@ -4,7 +4,9 @@ #define __MXL862XX_H #include <asm/byteorder.h> +#include <linux/bitops.h> #include <linux/mdio.h> +#include <linux/mutex.h> #include <linux/workqueue.h> #include <net/dsa.h> @@ -14,6 +16,10 @@ struct mxl862xx_priv; #define MXL862XX_FIRST_SERDES_PORT 9 #define MXL862XX_SERDES_SLOTS 4 +/* mxl862xx_rescue_mode_detect() return codes (negative values are errors) */ +#define MXL862XX_NOT_RESCUE 0 +#define MXL862XX_IN_RESCUE 1 + #define MXL862XX_DEFAULT_BRIDGE 0 #define MXL862XX_MAX_BRIDGES 48 #define MXL862XX_MAX_BRIDGE_PORTS 128 @@ -298,7 +304,8 @@ struct mxl862xx_fw_version { * before CRC-triggered shutdown and cleared after; * %MXL862XX_FLAG_WORK_STOPPED is set before cancelling * stats_work to prevent rescheduling during teardown - * and a flash + * and a flash, and ends the rescue drain and its + * reprobe hand-off * @drop_meter: index of the single shared zero-rate firmware meter * used to unconditionally drop traffic (used to block * flooding) @@ -340,6 +347,18 @@ struct mxl862xx_fw_version { * @shutting_down: set under the devlink instance lock once ->shutdown() * or .remove() has begun, so no flash starts while the * switch is going away + * @rescue_mode: switch is in MCUboot; firmware API commands fail fast, + * only clause-22 SMDIO works. Set from setup() before the + * switch is registered and cleared with WRITE_ONCE() under + * the MDIO bus lock for the benefit of mxl862xx_api_wrap(); + * readers outside that lock use READ_ONCE(). + * @rescue_ready: (rescue_mode) loader is at a clean READY and will accept + * a flash; false while rescue_heal_work is draining + * @rescue_failed: (rescue_mode) no flash is possible from this binding: + * an unfinishable handshake, a failed drain or a + * re-probe that could not be scheduled; the log names + * the cause, the devlink documentation the remedy + * @rescue_heal_work: background self-heal draining a wedged download to READY * @stats_work: periodic work item that polls RMON hardware counters * and accumulates them into 64-bit per-port stats */ @@ -347,6 +366,7 @@ struct mxl862xx_priv { struct dsa_switch *ds; struct mdio_device *mdiodev; struct work_struct crc_err_work; + struct work_struct rescue_heal_work; unsigned long flags; u16 drop_meter; struct mxl862xx_fw_version fw_version; @@ -364,6 +384,9 @@ struct mxl862xx_priv { bool block_host; bool skip_teardown; bool shutting_down; + bool rescue_mode; + bool rescue_ready; + bool rescue_failed; struct delayed_work stats_work; }; -- 2.56.0 ^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH net-next v19 5/6] net: dsa: mxl862xx: recover switch stuck in MCUboot rescue mode 2026-10-03 15:53 ` [PATCH net-next v19 5/6] net: dsa: mxl862xx: recover switch stuck in MCUboot rescue mode Daniel Golle @ 2026-10-04 14:45 ` Andrew Lunn 0 siblings, 0 replies; 3+ messages in thread From: Andrew Lunn @ 2026-10-04 14:45 UTC (permalink / raw) To: Daniel Golle Cc: Jiri Pirko, David S. Miller, Eric Dumazet, Jakub Kicinski, Paolo Abeni, Simon Horman, Jonathan Corbet, Shuah Khan, Randy Dunlap, Greg Kroah-Hartman, Rafael J. Wysocki, Danilo Krummrich, Vladimir Oltean, Russell King, netdev, linux-doc, linux-kernel, driver-core On Sat, Oct 03, 2026 at 04:53:34PM +0100, Daniel Golle wrote: > A broken or interrupted firmware image, or the sticky rescue bit, keeps > the switch in its MCUboot loader, which exposes only the clause-22 SMDIO > download interface. The clause-45 firmware API never comes up there, so > an ordinary probe would spend its whole timeout on a mailbox nothing > answers before failing. > > Assisted-by: LLM > Signed-off-by: Daniel Golle <daniel@makrotopia.org> Reviewed-by: Andrew Lunn <andrew@lunn.ch> Andrew ^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2026-10-04 15:56 UTC | newest] Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2026-10-04 15:56 [PATCH net-next v19 5/6] net: dsa: mxl862xx: recover switch stuck in MCUboot rescue mode netdev-bot+sashiko -- strict thread matches above, loose matches on Subject: below -- 2026-10-03 15:50 [PATCH net-next v19 0/6] net: dsa: mxl862xx: devlink flash and rescue Daniel Golle 2026-10-03 15:53 ` [PATCH net-next v19 5/6] net: dsa: mxl862xx: recover switch stuck in MCUboot rescue mode Daniel Golle 2026-10-04 14:45 ` Andrew Lunn
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