From patchwork Fri Mar 14 11:35:58 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Oleksij Rempel X-Patchwork-Id: 873725 Received: from metis.whiteo.stw.pengutronix.de (metis.whiteo.stw.pengutronix.de [185.203.201.7]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 192EE1FDE15 for ; Fri, 14 Mar 2025 11:36:21 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=185.203.201.7 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741952183; cv=none; b=VBBJDgWkB/MU9G+dhiuVXtqRuUzqpVzbjf+5PnhrhZlm4g6PTe1Fgp6GLQj0C3Tz+6cfqE9DvgE5oZkeufb7ZOWE3iMbLlyg5S9Pkcbfps9QnxUsy30DxLZM7pS43PH1UiWoqBZl12J2YCWPUPE1mEaSbnQJZdd30DThIs3XVD0= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741952183; c=relaxed/simple; bh=lTbHJ1/ZlZxy/0X5aGRTsmnSe0G1gRDQaLVCb3W0FPk=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=h3RXH07JasQwsaVBEnA9Lz5LC7HUqY/3VscvW0ITIvxklWBvo/h7AyQ4tI/JH7Lljhc4MCE2P8TmGo3EhD+Efze5tX1PFfdu37FVAnjqS8aWAtsa14gWP3eJmfSPRwCzDy2VQsZoHS4HVAKHxal/9uLtxSH5TNnmiRpARVKTnMg= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=pengutronix.de; spf=pass smtp.mailfrom=pengutronix.de; arc=none smtp.client-ip=185.203.201.7 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=pengutronix.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=pengutronix.de Received: from drehscheibe.grey.stw.pengutronix.de ([2a0a:edc0:0:c01:1d::a2]) by metis.whiteo.stw.pengutronix.de with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1tt3Kg-0007NZ-QE; Fri, 14 Mar 2025 12:36:06 +0100 Received: from dude04.red.stw.pengutronix.de ([2a0a:edc0:0:1101:1d::ac]) by drehscheibe.grey.stw.pengutronix.de with esmtps (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.96) (envelope-from ) id 1tt3Kf-005h5q-1t; Fri, 14 Mar 2025 12:36:05 +0100 Received: from ore by dude04.red.stw.pengutronix.de with local (Exim 4.96) (envelope-from ) id 1tt3Kf-007S64-1c; Fri, 14 Mar 2025 12:36:05 +0100 From: Oleksij Rempel To: Sebastian Reichel , Srinivas Kandagatla , Benson Leung , Tzung-Bi Shih , Daniel Lezcano Cc: Oleksij Rempel , kernel@pengutronix.de, linux-kernel@vger.kernel.org, Liam Girdwood , Mark Brown , "Rafael J. Wysocki" , Zhang Rui , Lukasz Luba , linux-pm@vger.kernel.org, =?utf-8?q?S=C3=B8ren_Andersen?= , Guenter Roeck , Matti Vaittinen , Ahmad Fatoum , Andrew Morton , chrome-platform@lists.linux.dev Subject: [PATCH v6 1/7] power: Extend power_on_reason.h for upcoming PSCRR framework Date: Fri, 14 Mar 2025 12:35:58 +0100 Message-Id: <20250314113604.1776201-2-o.rempel@pengutronix.de> X-Mailer: git-send-email 2.39.5 In-Reply-To: <20250314113604.1776201-1-o.rempel@pengutronix.de> References: <20250314113604.1776201-1-o.rempel@pengutronix.de> Precedence: bulk X-Mailing-List: linux-pm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-SA-Exim-Connect-IP: 2a0a:edc0:0:c01:1d::a2 X-SA-Exim-Mail-From: ore@pengutronix.de X-SA-Exim-Scanned: No (on metis.whiteo.stw.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: linux-pm@vger.kernel.org Prepare for the introduction of the Power State Change Reason Recorder (PSCRR) framework by expanding the power_on_reason.h header. This extension includes new power-on reasons: - POWER_ON_REASON_OVER_CURRENT for over-current conditions. - POWER_ON_REASON_REGULATOR_FAILURE for regulator failures. - POWER_ON_REASON_OVER_TEMPERATURE for over temperature situations. - POWER_ON_REASON_EC_PANIC for EC panics Signed-off-by: Oleksij Rempel --- changes v6: - add POWER_ON_REASON_EC_PANIC - s/POWER_ON_REASON_OVERTEMPERATURE/POWER_ON_REASON_OVER_TEMPERATURE --- include/linux/power/power_on_reason.h | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/include/linux/power/power_on_reason.h b/include/linux/power/power_on_reason.h index 95a1ec0c403c..bf9501792696 100644 --- a/include/linux/power/power_on_reason.h +++ b/include/linux/power/power_on_reason.h @@ -15,5 +15,9 @@ #define POWER_ON_REASON_XTAL_FAIL "crystal oscillator failure" #define POWER_ON_REASON_BROWN_OUT "brown-out reset" #define POWER_ON_REASON_UNKNOWN "unknown reason" +#define POWER_ON_REASON_OVER_CURRENT "over current" +#define POWER_ON_REASON_REGULATOR_FAILURE "regulator failure" +#define POWER_ON_REASON_OVER_TEMPERATURE "over temperature" +#define POWER_ON_REASON_EC_PANIC "EC panic" #endif /* POWER_ON_REASON_H */ From patchwork Fri Mar 14 11:35:59 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Oleksij Rempel X-Patchwork-Id: 873722 Received: from metis.whiteo.stw.pengutronix.de (metis.whiteo.stw.pengutronix.de [185.203.201.7]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 1B2ED1FDE19 for ; Fri, 14 Mar 2025 11:36:42 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=185.203.201.7 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741952205; cv=none; b=PWN9hmOaYTDAPrRXKwrVkcFS4DQqUyuvYzG91N7IyoCWMg0eClkwRWtAT04SZOsw8YjoZoJ6PCUU1zGH1ptohiFeVC0R9oegZh6KKtFelnhfHvBWaux1wU4RZAq7M9K1xnp3VDm+lg2dxyyzQ5cQChoJdKTugJffgMZwUErrD70= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741952205; c=relaxed/simple; bh=KzQDmvkgld6TQyzYhmK3aY8GTZDDrDkFej9Cz/eFIGI=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=ro/hlagW1L389LTz+wy1mY38FuDlfcUk0ON/ioTrwu0THVrnjfp2QyonYD+LVNL/Pzi8W8uo0kifSBSRjbxQ4ffINRKHU70J5P6QQ7O5Ag2zWMNN7Wmt/4ge/YRzVBReGFQB6r0TeZu3MYRNfmj0ZFh5Txi4WwZtMC4EqzCl64M= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=pengutronix.de; spf=pass smtp.mailfrom=pengutronix.de; arc=none smtp.client-ip=185.203.201.7 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=pengutronix.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=pengutronix.de Received: from drehscheibe.grey.stw.pengutronix.de ([2a0a:edc0:0:c01:1d::a2]) by metis.whiteo.stw.pengutronix.de with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1tt3Kg-0007Nb-QD; Fri, 14 Mar 2025 12:36:06 +0100 Received: from dude04.red.stw.pengutronix.de ([2a0a:edc0:0:1101:1d::ac]) by drehscheibe.grey.stw.pengutronix.de with esmtps (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.96) (envelope-from ) id 1tt3Kf-005h5r-1z; Fri, 14 Mar 2025 12:36:05 +0100 Received: from ore by dude04.red.stw.pengutronix.de with local (Exim 4.96) (envelope-from ) id 1tt3Kf-007S6E-1h; Fri, 14 Mar 2025 12:36:05 +0100 From: Oleksij Rempel To: Sebastian Reichel , Srinivas Kandagatla , Benson Leung , Tzung-Bi Shih , Daniel Lezcano Cc: Oleksij Rempel , kernel@pengutronix.de, linux-kernel@vger.kernel.org, Liam Girdwood , Mark Brown , "Rafael J. Wysocki" , Zhang Rui , Lukasz Luba , linux-pm@vger.kernel.org, =?utf-8?q?S=C3=B8ren_Andersen?= , Guenter Roeck , Matti Vaittinen , Ahmad Fatoum , Andrew Morton , chrome-platform@lists.linux.dev Subject: [PATCH v6 2/7] reboot: hw_protection_trigger: use standardized numeric shutdown/reboot reasons instead of strings Date: Fri, 14 Mar 2025 12:35:59 +0100 Message-Id: <20250314113604.1776201-3-o.rempel@pengutronix.de> X-Mailer: git-send-email 2.39.5 In-Reply-To: <20250314113604.1776201-1-o.rempel@pengutronix.de> References: <20250314113604.1776201-1-o.rempel@pengutronix.de> Precedence: bulk X-Mailing-List: linux-pm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-SA-Exim-Connect-IP: 2a0a:edc0:0:c01:1d::a2 X-SA-Exim-Mail-From: ore@pengutronix.de X-SA-Exim-Scanned: No (on metis.whiteo.stw.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: linux-pm@vger.kernel.org Prepares the kernel for the Power State Change Reason (PSCR) recorder, which will store shutdown and reboot reasons in persistent storage. Instead of using string-based reason descriptions, which are often too large to fit within limited storage spaces (e.g., RTC clocks with only 8 bits of battery-backed storage), we introduce `enum psc_reason`. This enumerates predefined reasons for power state changes, making it efficient to store and retrieve shutdown causes. Key changes: - Introduced `enum psc_reason`, defining structured reasons for power state changes. - Replaced string-based shutdown reasons with `psc_reason` identifiers. - Implemented `get_psc_reason()` and `set_psc_reason()` for tracking the last shutdown cause. - Added `psc_reason_to_str()` to map enum values to human-readable strings. - Updated `hw_protection_trigger()` to use `psc_reason` instead of string parameters. - Updated all consumers of `hw_protection_trigger()` to pass an appropriate `psc_reason` value instead of a string. Signed-off-by: Oleksij Rempel --- changes v6: - added in this version --- drivers/platform/chrome/cros_ec_lpc.c | 2 +- drivers/regulator/core.c | 7 ++- drivers/regulator/irq_helpers.c | 22 ++++--- drivers/thermal/thermal_core.c | 3 +- include/linux/reboot.h | 77 ++++++++++++++++++++++- kernel/reboot.c | 89 +++++++++++++++++++++++++-- 6 files changed, 182 insertions(+), 18 deletions(-) diff --git a/drivers/platform/chrome/cros_ec_lpc.c b/drivers/platform/chrome/cros_ec_lpc.c index 0b723c1e435c..235b259aeb30 100644 --- a/drivers/platform/chrome/cros_ec_lpc.c +++ b/drivers/platform/chrome/cros_ec_lpc.c @@ -454,7 +454,7 @@ static void cros_ec_lpc_acpi_notify(acpi_handle device, u32 value, void *data) blocking_notifier_call_chain(&ec_dev->panic_notifier, 0, ec_dev); kobject_uevent_env(&ec_dev->dev->kobj, KOBJ_CHANGE, (char **)env); /* Begin orderly shutdown. EC will force reset after a short period. */ - __hw_protection_trigger("CrOS EC Panic", -1, HWPROT_ACT_SHUTDOWN); + __hw_protection_trigger(PSCR_EC_PANIC, -1, HWPROT_ACT_SHUTDOWN); /* Do not query for other events after a panic is reported */ return; } diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c index 280559509dcf..de90e9ac9712 100644 --- a/drivers/regulator/core.c +++ b/drivers/regulator/core.c @@ -5243,6 +5243,7 @@ EXPORT_SYMBOL_GPL(regulator_bulk_free); static void regulator_handle_critical(struct regulator_dev *rdev, unsigned long event) { + enum psc_reason pscr; const char *reason = NULL; if (!rdev->constraints->system_critical) @@ -5251,18 +5252,22 @@ static void regulator_handle_critical(struct regulator_dev *rdev, switch (event) { case REGULATOR_EVENT_UNDER_VOLTAGE: reason = "System critical regulator: voltage drop detected"; + pscr = PSCR_UNDER_VOLTAGE; break; case REGULATOR_EVENT_OVER_CURRENT: reason = "System critical regulator: over-current detected"; + pscr = PSCR_OVER_CURRENT; break; case REGULATOR_EVENT_FAIL: reason = "System critical regulator: unknown error"; + pscr = PSCR_REGULATOR_FAILURE; } if (!reason) return; - hw_protection_trigger(reason, + rdev_crit(rdev, "%s\n", reason); + hw_protection_trigger(pscr, rdev->constraints->uv_less_critical_window_ms); } diff --git a/drivers/regulator/irq_helpers.c b/drivers/regulator/irq_helpers.c index 5742faee8071..31395a912341 100644 --- a/drivers/regulator/irq_helpers.c +++ b/drivers/regulator/irq_helpers.c @@ -63,17 +63,22 @@ static void regulator_notifier_isr_work(struct work_struct *work) reread: if (d->fatal_cnt && h->retry_cnt > d->fatal_cnt) { - if (!d->die) - return hw_protection_trigger("Regulator HW failure? - no IC recovery", + if (!d->die) { + pr_crit("Regulator HW failure? - no IC recovery\n"); + return hw_protection_trigger(PSCR_REGULATOR_FAILURE, REGULATOR_FORCED_SAFETY_SHUTDOWN_WAIT_MS); + } + ret = d->die(rid); /* * If the 'last resort' IC recovery failed we will have * nothing else left to do... */ - if (ret) - return hw_protection_trigger("Regulator HW failure. IC recovery failed", + if (ret) { + pr_crit("Regulator HW failure. IC recovery failed\n"); + return hw_protection_trigger(PSCR_REGULATOR_FAILURE, REGULATOR_FORCED_SAFETY_SHUTDOWN_WAIT_MS); + } /* * If h->die() was implemented we assume recovery has been @@ -263,14 +268,17 @@ static irqreturn_t regulator_notifier_isr(int irq, void *data) if (d->fatal_cnt && h->retry_cnt > d->fatal_cnt) { /* If we have no recovery, just try shut down straight away */ if (!d->die) { - hw_protection_trigger("Regulator failure. Retry count exceeded", + pr_crit("Regulator failure. Retry count exceeded\n"); + hw_protection_trigger(PSCR_REGULATOR_FAILURE, REGULATOR_FORCED_SAFETY_SHUTDOWN_WAIT_MS); } else { ret = d->die(rid); /* If die() failed shut down as a last attempt to save the HW */ - if (ret) - hw_protection_trigger("Regulator failure. Recovery failed", + if (ret) { + pr_crit("Regulator failure. Recovery failed\n"); + hw_protection_trigger(PSCR_REGULATOR_FAILURE, REGULATOR_FORCED_SAFETY_SHUTDOWN_WAIT_MS); + } } } diff --git a/drivers/thermal/thermal_core.c b/drivers/thermal/thermal_core.c index 5847729419f2..37cb58fd633e 100644 --- a/drivers/thermal/thermal_core.c +++ b/drivers/thermal/thermal_core.c @@ -377,11 +377,10 @@ static void thermal_zone_device_halt(struct thermal_zone_device *tz, * Its a must for forced_emergency_poweroff_work to be scheduled. */ int poweroff_delay_ms = CONFIG_THERMAL_EMERGENCY_POWEROFF_DELAY_MS; - const char *msg = "Temperature too high"; dev_emerg(&tz->device, "%s: critical temperature reached\n", tz->type); - __hw_protection_trigger(msg, poweroff_delay_ms, action); + __hw_protection_trigger(PSCR_OVER_TEMPERATURE, poweroff_delay_ms, action); } void thermal_zone_device_critical(struct thermal_zone_device *tz) diff --git a/include/linux/reboot.h b/include/linux/reboot.h index aa08c3bbbf59..6477910c6a9e 100644 --- a/include/linux/reboot.h +++ b/include/linux/reboot.h @@ -178,6 +178,73 @@ void ctrl_alt_del(void); extern void orderly_poweroff(bool force); extern void orderly_reboot(void); + +/** + * enum psc_reason - Enumerates reasons for power state changes. + * + * This enum defines various reasons why a system might transition into a + * shutdown, reboot, or kexec state. While originally intended for hardware + * protection events, `psc_reason` can be extended to track other system + * transitions, such as controlled reboots triggered by software or + * maintenance operations. + * + * The values in this enumeration provide structured and standardized + * identifiers that replace free-form string descriptions. They are designed + * to be stored efficiently, making them suitable for use in environments + * with limited storage, such as battery-backed RTC registers, non-volatile + * memory, or bootloader communication mechanisms. + * + * Importantly, the order of these values **must remain stable**, as + * bootloaders, user-space tools, or post-mortem investigation utilities + * may rely on their numerical representation for consistent behavior. + * + * @PSCR_UNKNOWN: Unknown or unspecified reason for the power state change. + * This value serves as a default when no explicit cause is recorded. + * + * @PSCR_UNDER_VOLTAGE: Shutdown or reboot triggered due to supply voltage + * dropping below a safe threshold. This helps prevent instability or + * corruption caused by insufficient power. + * + * @PSCR_OVER_CURRENT: System shutdown or reboot due to excessive current draw, + * which may indicate a short circuit, an overloaded power rail, or other + * hardware faults requiring immediate action. + * + * @PSCR_REGULATOR_FAILURE: A critical failure in a voltage regulator, causing + * improper power delivery. This may be due to internal component failure, + * transient conditions, or external load issues requiring mitigation. + * + * @PSCR_OVER_TEMPERATURE: System shutdown or reboot due to excessive thermal + * conditions. This attempts to prevent hardware damage when temperature + * sensors detect unsafe levels, often impacting CPUs, GPUs, or power + * components. + * + * @PSCR_EC_PANIC: Shutdown or reboot triggered by an Embedded Controller (EC) + * panic. The EC is a microcontroller responsible for low-level system + * management, including power sequencing, thermal control, and battery + * management. An EC panic may indicate critical firmware issues, power + * management errors, or an unrecoverable hardware fault requiring + * immediate response. + * + * @PSCR_REASON_COUNT: Number of defined power state change reasons. This + * value is useful for range checking and potential future extensions + * while maintaining compatibility. + */ +enum psc_reason { + PSCR_UNKNOWN, + PSCR_UNDER_VOLTAGE, + PSCR_OVER_CURRENT, + PSCR_REGULATOR_FAILURE, + PSCR_OVER_TEMPERATURE, + PSCR_EC_PANIC, + + /* Number of reasons */ + PSCR_REASON_COUNT, +}; + +#define PSCR_MAX_REASON (PSCR_REASON_COUNT - 1) + +const char *psc_reason_to_str(enum psc_reason reason); + /** * enum hw_protection_action - Hardware protection action * @@ -191,13 +258,13 @@ extern void orderly_reboot(void); */ enum hw_protection_action { HWPROT_ACT_DEFAULT, HWPROT_ACT_SHUTDOWN, HWPROT_ACT_REBOOT }; -void __hw_protection_trigger(const char *reason, int ms_until_forced, +void __hw_protection_trigger(enum psc_reason reason, int ms_until_forced, enum hw_protection_action action); /** * hw_protection_trigger - Trigger default emergency system hardware protection action * - * @reason: Reason of emergency shutdown or reboot to be printed. + * @reason: Reason of emergency shutdown or reboot. * @ms_until_forced: Time to wait for orderly shutdown or reboot before * triggering it. Negative value disables the forced * shutdown or reboot. @@ -206,11 +273,15 @@ void __hw_protection_trigger(const char *reason, int ms_until_forced, * hardware from further damage. The exact action taken is controllable at * runtime and defaults to shutdown. */ -static inline void hw_protection_trigger(const char *reason, int ms_until_forced) +static inline void hw_protection_trigger(enum psc_reason reason, + int ms_until_forced) { __hw_protection_trigger(reason, ms_until_forced, HWPROT_ACT_DEFAULT); } +enum psc_reason get_psc_reason(void); +void set_psc_reason(enum psc_reason reason); + /* * Emergency restart, callable from an interrupt handler. */ diff --git a/kernel/reboot.c b/kernel/reboot.c index 5299790a2832..138c5562bb6a 100644 --- a/kernel/reboot.c +++ b/kernel/reboot.c @@ -13,6 +13,7 @@ #include #include #include +#include #include #include #include @@ -49,6 +50,7 @@ int reboot_default = 1; int reboot_cpu; enum reboot_type reboot_type = BOOT_ACPI; int reboot_force; +enum psc_reason psc_last_reason = PSCR_UNKNOWN; struct sys_off_handler { struct notifier_block nb; @@ -1009,10 +1011,86 @@ static void hw_failure_emergency_schedule(enum hw_protection_action action, msecs_to_jiffies(action_delay_ms)); } +/** + * get_psc_reason - Retrieve the last recorded power state change reason. + * + * This function returns the most recent power state change reason stored + * in `psc_last_reason`. The value is set using `set_psc_reason()` when a + * shutdown, reboot, or kexec event occurs. + * + * The reason can be used for system diagnostics, post-mortem analysis, or + * debugging unexpected power state changes. Bootloaders or user-space tools + * may retrieve this value to determine why the system last transitioned to + * a new power state. + * + * Return: A value from `enum psc_reason`, indicating the last known power + * state change reason. + */ +enum psc_reason get_psc_reason(void) +{ + return READ_ONCE(psc_last_reason); +} +EXPORT_SYMBOL_GPL(get_psc_reason); + +/** + * set_psc_reason - Set the reason for the last power state change. + * + * @reason: A value from `enum psc_reason` indicating the cause of the power + * state change. + * + * This function records the reason for a shutdown, reboot, or kexec event + * by storing it in `psc_last_reason`. It ensures that the value remains + * consistent within the running system, allowing retrieval via + * `get_psc_reason()` for diagnostics, logging, or post-mortem analysis. + * + * Persistence Consideration: + * - This function **does not persist** the recorded reason across power cycles. + * - After a system reset or complete power loss, the recorded reason is lost. + * - To store power state change reasons persistently, additional tools such as + * the Power State Change Reason Recorder (PSCRR) framework should be used. + */ +void set_psc_reason(enum psc_reason reason) +{ + WRITE_ONCE(psc_last_reason, reason); +} +EXPORT_SYMBOL_GPL(set_psc_reason); + +/** + * psc_reason_to_str - Converts a power state change reason enum to a string. + * @reason: The `psc_reason` enum value to be converted. + * + * This function provides a human-readable string representation of the power + * state change reason, making it easier to interpret logs and debug messages. + * + * Return: + * - A string corresponding to the given `psc_reason` value. + * - `"Invalid"` if the value is not recognized. + */ +const char *psc_reason_to_str(enum psc_reason reason) +{ + switch (reason) { + case PSCR_UNKNOWN: + return POWER_ON_REASON_UNKNOWN; + case PSCR_UNDER_VOLTAGE: + return POWER_ON_REASON_BROWN_OUT; + case PSCR_OVER_CURRENT: + return POWER_ON_REASON_OVER_CURRENT; + case PSCR_REGULATOR_FAILURE: + return POWER_ON_REASON_REGULATOR_FAILURE; + case PSCR_OVER_TEMPERATURE: + return POWER_ON_REASON_OVER_TEMPERATURE; + case PSCR_EC_PANIC: + return POWER_ON_REASON_EC_PANIC; + default: + return "Invalid"; + } +} +EXPORT_SYMBOL_GPL(psc_reason_to_str); + /** * __hw_protection_trigger - Trigger an emergency system shutdown or reboot * - * @reason: Reason of emergency shutdown or reboot to be printed. + * @reason: Reason of emergency shutdown or reboot. * @ms_until_forced: Time to wait for orderly shutdown or reboot before * triggering it. Negative value disables the forced * shutdown or reboot. @@ -1024,7 +1102,7 @@ static void hw_failure_emergency_schedule(enum hw_protection_action action, * pending even if the previous request has given a large timeout for forced * shutdown/reboot. */ -void __hw_protection_trigger(const char *reason, int ms_until_forced, +void __hw_protection_trigger(enum psc_reason reason, int ms_until_forced, enum hw_protection_action action) { static atomic_t allow_proceed = ATOMIC_INIT(1); @@ -1032,8 +1110,11 @@ void __hw_protection_trigger(const char *reason, int ms_until_forced, if (action == HWPROT_ACT_DEFAULT) action = hw_protection_action; - pr_emerg("HARDWARE PROTECTION %s (%s)\n", - hw_protection_action_str(action), reason); + set_psc_reason(reason); + + pr_emerg("HARDWARE PROTECTION %s: %i (%s)\n", + hw_protection_action_str(action), reason, + psc_reason_to_str(reason)); /* Shutdown should be initiated only once. */ if (!atomic_dec_and_test(&allow_proceed)) From patchwork Fri Mar 14 11:36:01 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Oleksij Rempel X-Patchwork-Id: 873724 Received: from metis.whiteo.stw.pengutronix.de (metis.whiteo.stw.pengutronix.de [185.203.201.7]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 630841FE455 for ; Fri, 14 Mar 2025 11:36:25 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=185.203.201.7 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741952187; cv=none; b=D6fPF5lwNm0vNj3HDuNphVnrPYdxTMeg6+KXxRE7Zss166D2lmetocI1baNv77aEB7ClpBYZQcYyqdt8rbpeWV5f4Qdb5kAiQXa6m8H1XA6LxNBM/Ymm5h8ENXnZWMBSo/vzYDk2TN9GKnlSYtDSMiRQ1UsjZClIbClvSyGGAXs= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741952187; c=relaxed/simple; bh=uUmYJxs95mrM4B2aqNw/3s0vKcVGkdJCqAA4sx9f114=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=cAbJtbfLu8hPHBls8j/s+QsK3B+JR4Ore3X8GLOYI9K0CGqRNCxDGCj4hw0eJ8ujI/jPITykop2ArvhsmRMvvotWphZTFccdnxL+gzpRf+Fc0MJDa8dtxPhx3mcqZlK5ZCDqc78x6GxZUcLEekL85iMjPaoQwl8Orr0QoZxtvuY= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=pengutronix.de; spf=pass smtp.mailfrom=pengutronix.de; arc=none smtp.client-ip=185.203.201.7 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=pengutronix.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=pengutronix.de Received: from drehscheibe.grey.stw.pengutronix.de ([2a0a:edc0:0:c01:1d::a2]) by metis.whiteo.stw.pengutronix.de with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1tt3Kg-0007Nc-QD; Fri, 14 Mar 2025 12:36:06 +0100 Received: from dude04.red.stw.pengutronix.de ([2a0a:edc0:0:1101:1d::ac]) by drehscheibe.grey.stw.pengutronix.de with esmtps (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.96) (envelope-from ) id 1tt3Kf-005h5t-25; Fri, 14 Mar 2025 12:36:05 +0100 Received: from ore by dude04.red.stw.pengutronix.de with local (Exim 4.96) (envelope-from ) id 1tt3Kf-007S6Y-1o; Fri, 14 Mar 2025 12:36:05 +0100 From: Oleksij Rempel To: Sebastian Reichel , Srinivas Kandagatla , Benson Leung , Tzung-Bi Shih , Daniel Lezcano Cc: Oleksij Rempel , kernel@pengutronix.de, linux-kernel@vger.kernel.org, Liam Girdwood , Mark Brown , "Rafael J. Wysocki" , Zhang Rui , Lukasz Luba , linux-pm@vger.kernel.org, =?utf-8?q?S=C3=B8ren_Andersen?= , Guenter Roeck , Matti Vaittinen , Ahmad Fatoum , Andrew Morton , chrome-platform@lists.linux.dev Subject: [PATCH v6 4/7] nvmem: provide consumer access to cell size metrics Date: Fri, 14 Mar 2025 12:36:01 +0100 Message-Id: <20250314113604.1776201-5-o.rempel@pengutronix.de> X-Mailer: git-send-email 2.39.5 In-Reply-To: <20250314113604.1776201-1-o.rempel@pengutronix.de> References: <20250314113604.1776201-1-o.rempel@pengutronix.de> Precedence: bulk X-Mailing-List: linux-pm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-SA-Exim-Connect-IP: 2a0a:edc0:0:c01:1d::a2 X-SA-Exim-Mail-From: ore@pengutronix.de X-SA-Exim-Scanned: No (on metis.whiteo.stw.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: linux-pm@vger.kernel.org Add nvmem_cell_get_size() function to provide access to cell size metrics. In some cases we may get cell size less as consumer would expect it. So, nvmem_cell_write() would fail with incorrect buffer size. Signed-off-by: Oleksij Rempel --- changes v6: - update function comment for nvmem_cell_get_size() --- drivers/nvmem/core.c | 29 +++++++++++++++++++++++++++++ include/linux/nvmem-consumer.h | 7 +++++++ 2 files changed, 36 insertions(+) diff --git a/drivers/nvmem/core.c b/drivers/nvmem/core.c index fff85bbf0ecd..754a9448c39d 100644 --- a/drivers/nvmem/core.c +++ b/drivers/nvmem/core.c @@ -1828,6 +1828,35 @@ int nvmem_cell_write(struct nvmem_cell *cell, void *buf, size_t len) EXPORT_SYMBOL_GPL(nvmem_cell_write); +/** + * nvmem_cell_get_size() - Retrieve the storage size of an NVMEM cell. + * @cell: Pointer to the NVMEM cell structure. + * @bytes: Optional pointer to store the cell size in bytes (can be NULL). + * @bits: Optional pointer to store the cell size in bits (can be NULL). + * + * This function allows consumers to retrieve the size of a specific NVMEM + * cell before performing read/write operations. It is useful for validating + * buffer sizes to prevent mismatched writes. + * + * Return: 0 on success or negative on failure. + */ +int nvmem_cell_get_size(struct nvmem_cell *cell, size_t *bytes, size_t *bits) +{ + struct nvmem_cell_entry *entry = cell->entry; + + if (!entry->nvmem) + return -EINVAL; + + if (bytes) + *bytes = entry->bytes; + + if (bits) + *bits = entry->nbits; + + return 0; +} +EXPORT_SYMBOL_GPL(nvmem_cell_get_size); + static int nvmem_cell_read_common(struct device *dev, const char *cell_id, void *val, size_t count) { diff --git a/include/linux/nvmem-consumer.h b/include/linux/nvmem-consumer.h index 34c0e58dfa26..bcb0e17e415d 100644 --- a/include/linux/nvmem-consumer.h +++ b/include/linux/nvmem-consumer.h @@ -56,6 +56,7 @@ void nvmem_cell_put(struct nvmem_cell *cell); void devm_nvmem_cell_put(struct device *dev, struct nvmem_cell *cell); void *nvmem_cell_read(struct nvmem_cell *cell, size_t *len); int nvmem_cell_write(struct nvmem_cell *cell, void *buf, size_t len); +int nvmem_cell_get_size(struct nvmem_cell *cell, size_t *bytes, size_t *bits); int nvmem_cell_read_u8(struct device *dev, const char *cell_id, u8 *val); int nvmem_cell_read_u16(struct device *dev, const char *cell_id, u16 *val); int nvmem_cell_read_u32(struct device *dev, const char *cell_id, u32 *val); @@ -128,6 +129,12 @@ static inline int nvmem_cell_write(struct nvmem_cell *cell, return -EOPNOTSUPP; } +static inline int nvmem_cell_get_size(struct nvmem_cell *cell, size_t *bytes, + size_t *bits) +{ + return -EOPNOTSUPP; +} + static inline int nvmem_cell_read_u8(struct device *dev, const char *cell_id, u8 *val) { From patchwork Fri Mar 14 11:36:03 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Oleksij Rempel X-Patchwork-Id: 873723 Received: from metis.whiteo.stw.pengutronix.de (metis.whiteo.stw.pengutronix.de [185.203.201.7]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 924731FDE05 for ; Fri, 14 Mar 2025 11:36:27 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=185.203.201.7 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741952189; cv=none; b=LCCWl/To487Un1R/uVuNHW99fasZSf6yEH3/lI1bwPpYs+veceiwep2JHIccoVh7owUZbBps+U9Bjipxy0JmOPe+xnFV1LlrJZXiM0SaQKzf00k7SNJ7KqM3pxWOKpaxUYvuBBw9KQXWLYQqd4IqdrNlogn19YcxDV7FypElJAg= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741952189; c=relaxed/simple; bh=cWqrnz0iPUlouLQkAHvJFln5YMRL17uZKEqs7OguoTE=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=cGlhjo6YdrMvPv7BmrTSDX3PZOLfqblvJj/HdhZdUHK1zxI+ZXcYF6Vmi6bHZZr+ANjpsNi9BiYx9l0lVixw/yaVf6+USmqx1RHFvgf8lDfRNVYrgCsWYLCRfZVI9sql8a/E5DLel+N12hSkZOgtv20ImloDZhVfFMRUEciQVAg= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=pengutronix.de; spf=pass smtp.mailfrom=pengutronix.de; arc=none smtp.client-ip=185.203.201.7 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=pengutronix.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=pengutronix.de Received: from drehscheibe.grey.stw.pengutronix.de ([2a0a:edc0:0:c01:1d::a2]) by metis.whiteo.stw.pengutronix.de with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1tt3Kg-0007Ne-QD; Fri, 14 Mar 2025 12:36:06 +0100 Received: from dude04.red.stw.pengutronix.de ([2a0a:edc0:0:1101:1d::ac]) by drehscheibe.grey.stw.pengutronix.de with esmtps (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.96) (envelope-from ) id 1tt3Kf-005h5x-2H; Fri, 14 Mar 2025 12:36:05 +0100 Received: from ore by dude04.red.stw.pengutronix.de with local (Exim 4.96) (envelope-from ) id 1tt3Kf-007S6s-1v; Fri, 14 Mar 2025 12:36:05 +0100 From: Oleksij Rempel To: Sebastian Reichel , Srinivas Kandagatla , Benson Leung , Tzung-Bi Shih , Daniel Lezcano Cc: Oleksij Rempel , kernel@pengutronix.de, linux-kernel@vger.kernel.org, Liam Girdwood , Mark Brown , "Rafael J. Wysocki" , Zhang Rui , Lukasz Luba , linux-pm@vger.kernel.org, =?utf-8?q?S=C3=B8ren_Andersen?= , Guenter Roeck , Matti Vaittinen , Ahmad Fatoum , Andrew Morton , chrome-platform@lists.linux.dev Subject: [PATCH v6 6/7] power: reset: add PSCR NVMEM Driver for Recording Power State Change Reasons Date: Fri, 14 Mar 2025 12:36:03 +0100 Message-Id: <20250314113604.1776201-7-o.rempel@pengutronix.de> X-Mailer: git-send-email 2.39.5 In-Reply-To: <20250314113604.1776201-1-o.rempel@pengutronix.de> References: <20250314113604.1776201-1-o.rempel@pengutronix.de> Precedence: bulk X-Mailing-List: linux-pm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-SA-Exim-Connect-IP: 2a0a:edc0:0:c01:1d::a2 X-SA-Exim-Mail-From: ore@pengutronix.de X-SA-Exim-Scanned: No (on metis.whiteo.stw.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: linux-pm@vger.kernel.org This driver utilizes the Power State Change Reasons Recording (PSCRR) framework to store specific power state change information, such as shutdown or reboot reasons, into a designated non-volatile memory (NVMEM) cell. Signed-off-by: Oleksij Rempel --- changes v6: - rename pscr_reason to psc_reason changes v5: - avoid a build against NVMEM=m changes v4: - remove devicetree dependencies --- drivers/power/reset/Kconfig | 22 +++ drivers/power/reset/Makefile | 1 + drivers/power/reset/pscrr-nvmem.c | 254 ++++++++++++++++++++++++++++++ 3 files changed, 277 insertions(+) create mode 100644 drivers/power/reset/pscrr-nvmem.c diff --git a/drivers/power/reset/Kconfig b/drivers/power/reset/Kconfig index b874a04698df..e2267a6345d0 100644 --- a/drivers/power/reset/Kconfig +++ b/drivers/power/reset/Kconfig @@ -337,3 +337,25 @@ menuconfig PSCRR state transitions. If unsure, say N. + +if PSCRR + +config PSCRR_NVMEM + tristate "Generic NVMEM-based Power State Change Reason Recorder" + depends on NVMEM || !NVMEM + help + This option enables support for storing power state change reasons + (such as shutdown, reboot, or power failure events) into a designated + NVMEM (Non-Volatile Memory) cell. + + This feature allows embedded systems to retain power transition + history even after a full system restart or power loss. It is useful + for post-mortem debugging, automated recovery strategies, and + improving system reliability. + + The NVMEM cell used for storing these reasons can be dynamically + configured via module parameters. + + If unsure, say N. + +endif diff --git a/drivers/power/reset/Makefile b/drivers/power/reset/Makefile index dbd6ae6b26a4..532698552d40 100644 --- a/drivers/power/reset/Makefile +++ b/drivers/power/reset/Makefile @@ -33,6 +33,7 @@ obj-$(CONFIG_POWER_RESET_SYSCON) += syscon-reboot.o obj-$(CONFIG_POWER_RESET_SYSCON_POWEROFF) += syscon-poweroff.o obj-$(CONFIG_POWER_RESET_RMOBILE) += rmobile-reset.o obj-$(CONFIG_PSCRR) += pscrr.o +obj-$(CONFIG_PSCRR_NVMEM) += pscrr-nvmem.o obj-$(CONFIG_REBOOT_MODE) += reboot-mode.o obj-$(CONFIG_SYSCON_REBOOT_MODE) += syscon-reboot-mode.o obj-$(CONFIG_POWER_RESET_SC27XX) += sc27xx-poweroff.o diff --git a/drivers/power/reset/pscrr-nvmem.c b/drivers/power/reset/pscrr-nvmem.c new file mode 100644 index 000000000000..7d02d989893f --- /dev/null +++ b/drivers/power/reset/pscrr-nvmem.c @@ -0,0 +1,254 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * pscrr_nvmem.c - PSCRR backend for storing shutdown reasons in small NVMEM + * cells + * + * This backend provides a way to persist power state change reasons in a + * non-volatile memory (NVMEM) cell, ensuring that reboot causes can be + * analyzed post-mortem. Unlike traditional logging to eMMC or NAND, which + * may be unreliable during power failures, this approach allows storing + * reboot reasons in small, fast-access storage like RTC scratchpads, EEPROM, + * or FRAM. + * + * The module allows dynamic configuration of the NVMEM device and cell + * via module parameters: + * + * Example usage: + * modprobe pscrr-nvmem nvmem_name=pcf85063_nvram0 cell_name=pscr@0,0 + */ + +#include +#include +#include +#include +#include +#include +#include + +/* + * Module parameters: + * nvmem_name: Name of the NVMEM device (e.g. "pcf85063_nvram0"). + * cell_name : Sysfs name of the cell on that device (e.g. "pscr@0,0"). + */ +static char *nvmem_name; +module_param(nvmem_name, charp, 0444); +MODULE_PARM_DESC(nvmem_name, "Name of the NVMEM device (e.g. pcf85063_nvram0)"); + +static char *cell_name; +module_param(cell_name, charp, 0444); +MODULE_PARM_DESC(cell_name, "Sysfs name of the NVMEM cell (e.g. pscr@0,0)"); + +struct pscrr_nvmem_priv { + struct nvmem_device *nvmem; + struct nvmem_cell *cell; + + size_t total_bits; + size_t max_val; +}; + +static struct pscrr_nvmem_priv *priv; + +static int pscrr_nvmem_write_reason(enum psc_reason reason) +{ + size_t required_bytes; + u32 val; + int ret; + + if (!priv || !priv->cell) + return -ENODEV; + + /* Ensure reason fits in the available storage */ + if (reason > priv->max_val) { + pr_err("PSCRR-nvmem: Reason %d exceeds max storable value %zu for %zu-bit cell\n", + reason, priv->max_val, priv->total_bits); + return -ERANGE; + } + + val = reason; + + /* Determine required bytes for storing total_bits */ + required_bytes = (priv->total_bits + 7) / 8; + + /* Write the reason to the NVMEM cell */ + ret = nvmem_cell_write(priv->cell, &val, required_bytes); + if (ret < 0) { + pr_err("PSCRR-nvmem: Failed to write reason %d, err=%d (%pe)\n", + reason, ret, ERR_PTR(ret)); + return ret; + } + + pr_debug("PSCRR-nvmem: Successfully wrote reason %d\n", reason); + + return 0; +} + +static int pscrr_nvmem_read_reason(enum psc_reason *reason) +{ + size_t required_bytes, len; + unsigned int val; + int ret = 0; + void *buf; + + if (!priv || !priv->cell) + return -ENODEV; + + buf = nvmem_cell_read(priv->cell, &len); + if (IS_ERR(buf)) { + ret = PTR_ERR(buf); + pr_err("PSCRR-nvmem: Failed to read cell, err=%d (%pe)\n", ret, + ERR_PTR(ret)); + return ret; + } + + /* Calculate the required number of bytes */ + required_bytes = (priv->total_bits + 7) / 8; + + /* Validate that the returned length is large enough */ + if (len < required_bytes) { + pr_err("PSCRR-nvmem: Read length %zu is too small (need at least %zu bytes)\n", + len, required_bytes); + kfree(buf); + return -EIO; + } + + /* Extract value safely with proper memory alignment handling */ + val = 0; + memcpy(&val, buf, required_bytes); + + /* Mask only the necessary bits to avoid garbage data */ + val &= (1U << priv->total_bits) - 1; + + kfree(buf); + + *reason = (enum psc_reason)val; + + pr_debug("PSCRR-nvmem: Read reason => %d (from %zu bytes, %zu bits used)\n", + *reason, len, priv->total_bits); + + return 0; +} + +static const struct pscrr_backend_ops pscrr_nvmem_ops = { + .write_reason = pscrr_nvmem_write_reason, + .read_reason = pscrr_nvmem_read_reason, +}; + +static int __init pscrr_nvmem_init(void) +{ + size_t bytes, bits; + int ret; + + if (!nvmem_name || !cell_name) { + pr_err("PSCRR-nvmem: Must specify both nvmem_name and cell_name.\n"); + return -EINVAL; + } + + priv = kzalloc(sizeof(*priv), GFP_KERNEL); + if (!priv) + return -ENOMEM; + + priv->nvmem = nvmem_device_get_by_name(nvmem_name); + if (IS_ERR(priv->nvmem)) { + ret = PTR_ERR(priv->nvmem); + pr_err("PSCRR-nvmem: nvmem_device_get_by_name(%s) failed: %d\n", + nvmem_name, ret); + priv->nvmem = NULL; + goto err_free; + } + + priv->cell = nvmem_cell_get_by_sysfs_name(priv->nvmem, cell_name); + if (IS_ERR(priv->cell)) { + ret = PTR_ERR(priv->cell); + pr_err("PSCRR-nvmem: nvmem_cell_get_by_sysfs_name(%s) failed, err=%pe\n", + cell_name, ERR_PTR(ret)); + priv->cell = NULL; + goto err_dev_put; + } + + ret = nvmem_cell_get_size(priv->cell, &bytes, &bits); + if (ret < 0) { + pr_err("PSCRR-nvmem: Failed to get cell size, err=%pe\n", + ERR_PTR(ret)); + goto err_cell_put; + } + + if (bits) + priv->total_bits = bits; + else + priv->total_bits = bytes * 8; + + if (priv->total_bits > 31) { + pr_err("PSCRR-nvmem: total_bits=%zu is too large (max 31 allowed)\n", + priv->total_bits); + return -EOVERFLOW; + } + + priv->max_val = (1 << priv->total_bits) - 1; + pr_debug("PSCRR-nvmem: Cell size: %zu bytes + %zu bits => total_bits=%zu\n", + bytes, bits, priv->total_bits); + + /* + * If we store reasons 0..PSCR_MAX_REASON, the largest needed is + * 'PSCR_MAX_REASON'. That must fit within total_bits. + * So the max storable integer is (1 << total_bits) - 1. + */ + if (priv->max_val < PSCR_MAX_REASON) { + pr_err("PSCRR-nvmem: Not enough bits (%zu) to store up to reason=%d\n", + priv->total_bits, PSCR_MAX_REASON); + ret = -ENOSPC; + goto err_cell_put; + } + + /* 4. Register with pscrr_core. */ + ret = pscrr_core_init(&pscrr_nvmem_ops); + if (ret) { + pr_err("PSCRR-nvmem: pscrr_core_init() failed: %d\n", ret); + goto err_cell_put; + } + + pr_info("PSCRR-nvmem: Loaded (nvmem=%s, cell=%s), can store 0..%zu\n", + nvmem_name, cell_name, priv->max_val); + return 0; + +err_cell_put: + if (priv->cell) { + nvmem_cell_put(priv->cell); + priv->cell = NULL; + } +err_dev_put: + if (priv->nvmem) { + nvmem_device_put(priv->nvmem); + priv->nvmem = NULL; + } +err_free: + kfree(priv); + priv = NULL; + return ret; +} + +static void __exit pscrr_nvmem_exit(void) +{ + pscrr_core_exit(); + + if (priv) { + if (priv->cell) { + nvmem_cell_put(priv->cell); + priv->cell = NULL; + } + if (priv->nvmem) { + nvmem_device_put(priv->nvmem); + priv->nvmem = NULL; + } + kfree(priv); + priv = NULL; + } + + pr_info("pscrr-nvmem: Unloaded\n"); +} + +module_init(pscrr_nvmem_init); +module_exit(pscrr_nvmem_exit); + +MODULE_AUTHOR("Oleksij Rempel "); +MODULE_DESCRIPTION("PSCRR backend for storing reason code in NVMEM"); +MODULE_LICENSE("GPL");