[PATCH v19 04/10] firmware: psci: Introduce command-based reset in psci_sys_reset
From: Shivendra Pratap <hidden>
Date: 2025-12-28 17:21:12
Also in:
linux-arm-msm, linux-devicetree, linux-pm, lkml
Subsystem:
power state coordination interface (psci), the rest · Maintainers:
Mark Rutland, Lorenzo Pieralisi, Linus Torvalds
PSCI currently supports only COLD reset and ARCH WARM reset based on the Linux reboot_mode variable. The PSCI specification now includes SYSTEM_RESET2 for vendor-specific resets, but there's no mechanism to issue these through psci_sys_reset. Add a command-based reset mechanism that allows external drivers to set the psci reset command via a new psci_set_reset_cmd() function. The psci command-based reset is disabled by default and the psci_sys_reset follows its original flow until a psci_reset command is set or a kernel panic is in progress. Signed-off-by: Shivendra Pratap <redacted> --- drivers/firmware/psci/psci.c | 46 ++++++++++++++++++++++++++++++++++++++++++-- include/linux/psci.h | 2 ++ 2 files changed, 46 insertions(+), 2 deletions(-)
diff --git a/drivers/firmware/psci/psci.c b/drivers/firmware/psci/psci.c
index 38ca190d4a22d6e7e0f06420e8478a2b0ec2fe6f..ad7a3267276f9e26740aea99c11f171ac715f9ba 100644
--- a/drivers/firmware/psci/psci.c
+++ b/drivers/firmware/psci/psci.c@@ -51,6 +51,15 @@ static int resident_cpu = -1; struct psci_operations psci_ops; static enum arm_smccc_conduit psci_conduit = SMCCC_CONDUIT_NONE; +struct psci_sys_reset_params { + u32 system_reset; + u32 reset_type; + u32 cookie; + bool cmd; +}; + +static struct psci_sys_reset_params psci_reset; + bool psci_tos_resident_on(int cpu) { return cpu == resident_cpu;
@@ -80,6 +89,29 @@ static u32 psci_cpu_suspend_feature; static bool psci_system_reset2_supported; static bool psci_system_off2_hibernate_supported; +/** + * psci_set_reset_cmd - Sets the psci_reset_cmd for command-based + * reset which will be used in psci_sys_reset call. + * + * @cmd_sys_rst2: Set to true for SYSTEM_RESET2 based resets. + * @cmd_reset_type: Set the reset_type argument for psci_sys_reset. + * @cmd_cookie: Set the cookie argument for psci_sys_reset. + */ +void psci_set_reset_cmd(bool cmd_sys_rst2, u32 cmd_reset_type, u32 cmd_cookie) +{ + if (cmd_sys_rst2 && psci_system_reset2_supported) { + psci_reset.system_reset = PSCI_FN_NATIVE(1_1, SYSTEM_RESET2); + psci_reset.reset_type = cmd_reset_type; + psci_reset.cookie = cmd_cookie; + } else { + psci_reset.system_reset = PSCI_0_2_FN_SYSTEM_RESET; + psci_reset.reset_type = 0; + psci_reset.cookie = 0; + } + psci_reset.cmd = true; +} +EXPORT_SYMBOL_GPL(psci_set_reset_cmd); + static inline bool psci_has_ext_power_state(void) { return psci_cpu_suspend_feature &
@@ -309,14 +341,24 @@ static int get_set_conduit_method(const struct device_node *np) static int psci_sys_reset(struct notifier_block *nb, unsigned long action, void *data) { - if ((reboot_mode == REBOOT_WARM || reboot_mode == REBOOT_SOFT) && - psci_system_reset2_supported) { + if (((reboot_mode == REBOOT_WARM || reboot_mode == REBOOT_SOFT) && + psci_system_reset2_supported) && (panic_in_progress() || !psci_reset.cmd)) { /* * reset_type[31] = 0 (architectural) * reset_type[30:0] = 0 (SYSTEM_WARM_RESET) * cookie = 0 (ignored by the implementation) */ invoke_psci_fn(PSCI_FN_NATIVE(1_1, SYSTEM_RESET2), 0, 0, 0); + } else if (!panic_in_progress() && psci_reset.cmd) { + /* + * Commands are being set in psci_set_reset_cmd + * This issues, SYSTEM_RESET2 arch warm reset or + * SYSTEM_RESET2 vendor-specific reset or + * a SYSTEM_RESET cold reset in accordance with + * the reboot-mode command. + */ + invoke_psci_fn(psci_reset.system_reset, psci_reset.reset_type, + psci_reset.cookie, 0); } else { invoke_psci_fn(PSCI_0_2_FN_SYSTEM_RESET, 0, 0, 0); }
diff --git a/include/linux/psci.h b/include/linux/psci.h
index 4ca0060a3fc42ba1ca751c7862fb4ad8dda35a4c..d13ceca88eab8932894051e7c86e806c2ad8a73a 100644
--- a/include/linux/psci.h
+++ b/include/linux/psci.h@@ -45,8 +45,10 @@ struct psci_0_1_function_ids get_psci_0_1_function_ids(void); #if defined(CONFIG_ARM_PSCI_FW) int __init psci_dt_init(void); +void psci_set_reset_cmd(bool cmd_sys_rst2, u32 cmd_reset_type, u32 cmd_cookie); #else static inline int psci_dt_init(void) { return 0; } +static inline void psci_set_reset_cmd(bool cmd_sys_rst2, u32 cmd_reset_type, u32 cmd_cookie) { } #endif #if defined(CONFIG_ARM_PSCI_FW) && defined(CONFIG_ACPI)
--
2.34.1