Re: [PATCH v10 00/10] Implement vendor resets for PSCI SYSTEM_RESET2

[Florian Fainelli <florian.fainelli@broadcom.com>]

On 7/10/25 02:15, Shivendra Pratap wrote:
> The PSCI SYSTEM_RESET2 call allows vendor firmware to define
> additional reset types which could be mapped to the reboot
> argument.
>   
> User-space should be able to reboot a device into different
> operational boot-states supported by underlying bootloader and
> firmware. Generally, some HW registers need to be written, based
> on which the bootloader and firmware decide the next boot state
> of device, after the reset. For example, a requirement on
> Qualcomm platforms may state that reboot with "bootloader"
> command, should reboot the device into bootloader flashing mode
> and reboot with “edl” command, should reboot the device into an
> Emergency flashing mode.  Setting up such reboots on Qualcomm
> devices can be inconsistent across SoC platforms and may require
> setting different HW registers, where some of these registers may
> not be accessible to HLOS. These knobs evolve over product
> generations and require more drivers.  PSCI defines a
> vendor-specific reset in SYSTEM_RESET2 spec, which enables the
> firmware to take care of underlying setting for any such
> supported vendor-specific reboot. Qualcomm firmwares are
> beginning to support and expose PSCI SYSTEM_RESET2
> vendor-specific reset types to simplify driver requirements from
> Linux. With such support added in the firmware, we now need a
> Linux interface which can make use of the firmware calls for PSCI
> vendor-specific resets. This will align such reboot requirement
> across platforms and vendors.
>   
> The current psci driver supports two types of resets –
> SYSTEM_RESET2 Arch warm-reset and SYSTEM_RESET cold-reset. The
> patchset introduces the PSCI SYSTEM_RESET2 vendor-specific reset
> into the reset path of the psci driver and aligns it to work with
> reboot system call - LINUX_REBOOT_CMD_RESTART2, when used along
> with a supported string-based command in “*arg”.
> 
> The patchset uses reboot-mode based commands, to define the
> supported vendor reset-types commands in psci device tree node
> and registers these commands with the reboot-mode framework.
> 
> The PSCI vendor-specific reset takes two arguments, being,
> reset_type and cookie as defined by the spec. As the
> vendor-specific reset needs two arguments reset_type and cookie
> to be passes to the firmware, enhance the reboot-mode framework
> to support two arguments (magic and cookie), for each reboot-mode
> command, where cookie will be optional.
> 
> Along this line, the patchset also extends the reboot-mode
> framework to add a non-device-based registration function which
> will allow drivers to register using DT node, while keeping
> backward compatibility for existing users of reboot-mode. This
> will enable psci driver to register for reboot-mode and implement
> a write_with_cookie function which will save the
> magic(reset_type) and cookie and then use it in psci reset path
> to make a vendor-specific reset call into the firmware. In
> addition, the patchset will expose a sysfs entry interface within
> reboot-mode which can be used by userspace to view the supported
> reboot-mode commands.
> 
> The list of vendor-specific reset commands remains open due to
> divergent requirements across vendors, but this can be
> streamlined and standardized through dedicated device tree
> bindings.
> 
> Currently three drivers register with reboot-mode framework -
> syscon-reboot-mode, nvmem-reboot-mode and qcom-pon. Consolidated
> list of commands currently added across various vendor DTs:
>   mode-loader
>   mode-normal
>   mode-bootloader
>   mode-charge
>   mode-fastboot
>   mode-reboot-ab-update
>   mode-recovery
>   mode-rescue
>   mode-shutdown-thermal
>   mode-shutdown-thermal-battery
> 
> Detailed list of commands being used by syscon-reboot-mode:
>      arm64/boot/dts/exynos/exynosautov9.dtsi:
> 	mode-bootloader = <EXYNOSAUTOV9_BOOT_BOOTLOADER>;
> 	mode-fastboot = <EXYNOSAUTOV9_BOOT_FASTBOOT>;
> 	mode-recovery = <EXYNOSAUTOV9_BOOT_RECOVERY>;
> 
>      arm64/boot/dts/exynos/google/gs101.dtsi:
>      	mode-bootloader = <0xfc>;
>      	mode-charge = <0x0a>;
>      	mode-fastboot = <0xfa>;
>      	mode-reboot-ab-update = <0x52>;
>      	mode-recovery = <0xff>;
>      	mode-rescue = <0xf9>;
>      	mode-shutdown-thermal = <0x51>;
>      	mode-shutdown-thermal-battery = <0x51>;
> 
>      arm64/boot/dts/hisilicon/hi3660-hikey960.dts:
>      	mode-normal = <0x77665501>;
>      	mode-bootloader = <0x77665500>;
>      	mode-recovery = <0x77665502>;
> 
>      arm64/boot/dts/hisilicon/hi6220-hikey.dts:
>      	mode-normal = <0x77665501>;
>      	mode-bootloader = <0x77665500>;
>      	mode-recovery = <0x77665502>;
> 
>      arm64/boot/dts/rockchip/px30.dtsi:
>      	mode-bootloader = <BOOT_BL_DOWNLOAD>;
>      	mode-fastboot = <BOOT_FASTBOOT>;
>      	mode-loader = <BOOT_BL_DOWNLOAD>;
>      	mode-normal = <BOOT_NORMAL>;
>      	mode-recovery = <BOOT_RECOVERY>;
> 
>      arm64/boot/dts/rockchip/rk3308.dtsi:			
>      	mode-bootloader = <BOOT_BL_DOWNLOAD>;
>      	mode-loader = <BOOT_BL_DOWNLOAD>;
>      	mode-normal = <BOOT_NORMAL>;
>      	mode-recovery = <BOOT_RECOVERY>;
>      	mode-fastboot = <BOOT_FASTBOOT>;
> 
>      arm64/boot/dts/rockchip/rk3566-lckfb-tspi.dts:
>      	mode-normal = <BOOT_NORMAL>;
>      	mode-loader = <BOOT_BL_DOWNLOAD>;
> 			mode-recovery = <BOOT_RECOVERY>;
> 			mode-bootloader = <BOOT_FASTBOOT>;
> 
> Detailed list of commands being used by nvmem-reboot-mode:
>      arm64/boot/dts/qcom/pmXXXX.dtsi:(multiple qcom DTs)
> 			mode-recovery = <0x01>;
> 			mode-bootloader = <0x02>;
> 
> Previous discussions around SYSTEM_RESET2:
> - https://lore.kernel.org/lkml/20230724223057.1208122-2-quic_eberman@quicinc.com/T/
> - https://lore.kernel.org/all/4a679542-b48d-7e11-f33a-63535a5c68cb@quicinc.com/
> 
> Signed-off-by: Elliot Berman <quic_eberman@quicinc.com>
> Signed-off-by: Shivendra Pratap <shivendra.pratap@oss.qualcomm.com>

Humm, something changed compared to the last version that I tested from 
Elliot which worked ok. With this patch applied and the following Device 
Tree snippet:

         psci {
                 method = "smc";
                 compatible = "arm,psci-0.2", "arm,psci";
                 cpu_on = <0xc4000003>;
                 cpu_suspend = <0xc4000001>;
                 cpu_off = <0x84000002>;

                 reset-types {
                         mode-powercycle = <0x01>;
                 };
         };

I get the following invoking "reboot powercycle":

# reboot powercycle
[   21.403188] Unable to handle kernel NULL pointer dereference at 
virtual address 0000000000000000 is not a phandle reference
[   21.412032] Mem abort info:extended_property): 
/rdb/waketimer@841a840:interrupts-extended: cell 0 is not a phandle 
reference
[   21.414840]   ESR = 0x0000000086000004operty): 
/rdb/waketimer@841a840:interrupts-extended: cell 2 is not a phandle 
reference
[   21.418601]   EC = 0x21: IABT (current EL), IL = 32 bitsparent: cell 
0 is not a phandle reference
[   21.423927]   SET = 0, FnV = 0: /rdb/xhci_v2@8d00000:phys: cell 0 is 
not a phandle reference
[   21.426988]   EA = 0, S1PTW = 0 /rdb/sata@8b0a000/sata-port@0:phys: 
cell 0 is not a phandle reference
[   21.430138]   FSC = 0x04: level 0 translation fault:phys: cell 0 is 
not a phandle reference
[   21.435054] user pgtable: 4k pages, 48-bit VAs, pgdp=000000010112c000 
a phandle reference
[   21.441508] [0000000000000000] pgd=0000000000000000, 
p4d=0000000000000000handle reference
[   21.448318] Internal error: Oops: 0000000086000004 [#1]  SMPcell 0 is 
not a phandle reference
[   21.453990] Modules linked in: bdc 
udc_core/thermal-zones/cpu-thermal:thermal-sensors: cell 0 is not a 
phandle reference
[   21.458188] CPU: 0 UID: 0 PID: 1566 Comm: reboot Not tainted 
6.16.0-rc5-next-20250710-gdd78270edd5a #2 NONE 4)
[   21.468032] Hardware name: BCX972160DV (DT)ases property name must 
include only lowercase and '-'
[   21.472221] pstate: 60000005 (nZCv daif -PAN -UAO -TCO -DIT -SSBS 
BTYPE=--)only lowercase and '-'
[   21.479193] pc : 0x0s_paths): /aliases:pcie0: aliases property is not 
a valid node (/pcie@8b10000)
[   21.481388] lr : reboot_mode_notify+0x64/0x80es property name must 
include only lowercase and '-'
[   21.485760] sp : ffff80008344bbe0iases: aliases property name must 
include only lowercase and '-'
[   21.489079] x29: ffff80008344bbe0 x28: ffff0000c3bb3d00 x27: 
ffff800080ab58e8ly lowercase and '-'
[   21.496228] x26: 0000000000000000 x25: ffff0000c3bb3d00 x24: 
ffff800082cf9bc8ly lowercase and '-'
[   21.503376] x23: ffff80008344bcb8 x22: 0000000000000001 x21: 
ffff0000c31b87b0
[   21.510524] x20: 00000000fffffffc x19: ffff0000c31b8780 x18: 
0000000000000000
[   21.517673] x17: 0000000000000000 x16: 0000000000000000 x15: 
0000000000000000
[   21.524821] x14: 0000000000000000 x13: 0000000000000000 x12: 
0000000000000000
[   21.531969] x11: 0000000000000000 x10: 00007fffc02bb958 x9 : 
0000000000000010
[   21.539118] x8 : 0101010101010101 x7 : 0000000000000000 x6 : 
000080c38080ffff
[   21.546266] x5 : ffff0000c3000000 x4 : 0000808000800000 x3 : 
0000000000000000
[   21.553415] x2 : 0000000000000000 x1 : 0000000000000001 x0 : 
ffff0000c31b8780
[   21.560565] Call trace:
[   21.563014]  0x0 (P)
[   21.565205]  notifier_call_chain+0x70/0x120
[   21.569401]  blocking_notifier_call_chain+0x4c/0x78
[   21.574288]  kernel_restart+0x30/0xc8
[   21.577957]  __do_sys_reboot+0x1c8/0x268
[   21.581886]  __arm64_sys_reboot+0x28/0x38
[   21.585902]  invoke_syscall+0x4c/0x118
[   21.589660]  el0_svc_common.constprop.0+0x44/0xe8
[   21.594373]  do_el0_svc+0x20/0x30
[   21.597694]  el0_svc+0x18/0x58
[   21.600758]  el0t_64_sync_handler+0x98/0xe0
[   21.604947]  el0t_64_sync+0x154/0x158
[   21.608625] Code: ???????? ???????? ???????? ???????? (????????)
[   21.614730] ---[ end trace 0000000000000000 ]---
Segmentation fault
#

--
Florian