[PATCH v10 00/10] Implement vendor resets for PSCI SYSTEM_RESET2
Florian Fainelli
florian.fainelli at broadcom.com
Thu Jul 10 13:20:06 PDT 2025
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 at quicinc.com>
> Signed-off-by: Shivendra Pratap <shivendra.pratap at 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 at 841a840:interrupts-extended: cell 0 is not a phandle
reference
[ 21.414840] ESR = 0x0000000086000004operty):
/rdb/waketimer at 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 at 8d00000:phys: cell 0 is
not a phandle reference
[ 21.426988] EA = 0, S1PTW = 0 /rdb/sata at 8b0a000/sata-port at 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 at 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
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