Re: [PATCH 1/2] wifi: rtw88: 8703b: complete the card-disable to card-emulation transition

[Ping-Ke Shih <pkshih@realtek.com>]

Cristian Deluxe <me@cristiandeluxe.dev> wrote:

> On an RTL8723CS the driver cannot power the MAC on after a warm reboot:
> the power-on sequence waits forever for power ready and probe fails.
> 
>   rtw88_8723cs mmc2:0001:1: failed to poll offset=0x6 mask=0x2 value=0x2
>   rtw88_8723cs mmc2:0001:1: mac power on failed
> 
> trans_carddis_to_cardemu_8703b has a single entry, clearing the hardware
> power-down bit. Its sibling trans_carddis_to_cardemu_8723d has six more,
> and 8822b and 8822c carry the same SDIO pair: withdraw the SDIO suspend
> request on local register 0x86 and wait for the interface to leave the
> suspended state, clear the WL suspend bit alongside the power-down bit,
> and take the 12H LDO out of sleep mode. The transition is the reverse of
> trans_cardemu_to_carddis_8703b, which sets 0x23[4] and asks the
> interface to suspend, so with those operations missing neither is ever
> undone.
> 
> The chip then comes back with the WLAN MAC unpowered while the SDIO
> function still enumerates and CMD52 still works, and nothing in the
> sequence wakes it. rtw_mac_pre_system_cfg() does not cover it either: it
> returns early for 8051 wcpu chips, of which this is one.
> 
> It survives a reboot on any board where WL_REG_ON is the only reset the
> host has and the chip's rail is not switchable. On the Denver TAQ-102
> the pwrseq reset line, the BT enable line, the 32.768 kHz clock and
> every switchable PMIC rail were each toggled against a wedged chip and
> none of them cleared it, while the vendor driver recovered it every
> time.
> 
> Take the operations 8723d has and this table lacks. That table's USB-only
> and PCI-only entries are left out: this chip has no such variant.
> 
> Tested on an RTL8723CS over SDIO: recovers a chip left wedged by a
> previous boot, and survives repeated warm reboots and loader-mode flash
> cycles.
> 
> Signed-off-by: Cristian Deluxe <me@cristiandeluxe.dev>
> Acked-by: Ping-Ke Shih <pkshih@realtek.com>

2 patch(es) applied to rtw-next branch of rtw.git, thanks.

43f6347e8bbe wifi: rtw88: 8703b: complete the card-disable to card-emulation transition
73e3b1c94c7d wifi: rtw88: 8703b: stop the PCIe DMA write reaching SDIO

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https://github.com/pkshih/rtw.git