From nobody Wed Dec 17 22:44:23 2025 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 1CC2C1FAC3B for ; Fri, 14 Mar 2025 11:36:31 +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=1741952193; cv=none; b=WBznu0cN4yBP/UlHLZdU5nTcex43iEeBwDot2iBKpWYG7NeZ5eBugyJy+ne9XddFUNb3vTogfBYRIu1wzLSLA5MeDOLYuVqntooBeJhlEJaqeMoehcRjikLxYZhGXWyF1BpgQUJbdElGtrVPpUs5hlstnCZ5dI65tSxvsnfPBWA= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741952193; c=relaxed/simple; bh=BM2P1+sWqXKKZwR/jHqONVfULGU+/JuCKI63iVNdZTM=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=EGLbJycSFN66qPIqurALc2EKua2qZWuSbP3mW/SoFcq7Tczp4FupVSQDIma5Lwx2YHgFjjWSOEW/Q6lwgKvNyJONd9c5CATkCjgWfDR92Xj44pQkdnSQ7acQDgWWD0WCzYwGFnZ7EBzNGvwz9d//VNlhlhzMRHS+nE/sjnAKyXI= 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-0007Nf-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-005h5z-2K; 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-007S73-1z; 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=20Andersen?= , Guenter Roeck , Matti Vaittinen , Ahmad Fatoum , Andrew Morton , chrome-platform@lists.linux.dev Subject: [PATCH v6 7/7] Documentation: Add sysfs documentation for PSCRR reboot reason tracking Date: Fri, 14 Mar 2025 12:36:04 +0100 Message-Id: <20250314113604.1776201-8-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-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable 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-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" Add documentation for the Power State Change Reason Recorder (PSCRR) sysfs interface, which allows tracking of system shutdown and reboot reasons. The documentation provides details on available sysfs entries under `/sys/kernel/pscrr/`, explaining their functionality, example usage, and how they interact with different backend storage options (e.g., NVMEM). Signed-off-by: Oleksij Rempel --- .../ABI/testing/sysfs-kernel-reboot-pscrr | 46 +++++++++++++++++++ 1 file changed, 46 insertions(+) create mode 100644 Documentation/ABI/testing/sysfs-kernel-reboot-pscrr diff --git a/Documentation/ABI/testing/sysfs-kernel-reboot-pscrr b/Document= ation/ABI/testing/sysfs-kernel-reboot-pscrr new file mode 100644 index 000000000000..7cc643f89675 --- /dev/null +++ b/Documentation/ABI/testing/sysfs-kernel-reboot-pscrr @@ -0,0 +1,46 @@ +What: /sys/kernel/pscrr/reason +Date: April 2025 +KernelVersion: 6.15 +Contact: Oleksij Rempel +Description: + This file provides access to the last recorded power state + change reason. The storage backend is configurable and, if + supported, the reason may be stored persistently in an + NVMEM cell or another backend. + + Reading this file returns an integer representing the last + recorded shutdown or reboot cause. + + Writing an integer value to this file sets the reason to be + stored and recorded for system analysis. + + Example usage (values are for illustration and may not reflect + actual reasons used in a given system): + Read: + $ cat /sys/kernel/pscrr/reason + 3 # (Example: Power loss event, may differ per system) + + Write: + $ echo 5 > /sys/kernel/pscrr/reason + # Sets the reason to 5 (Example: User-triggered reboot, + # this may not be a real value in your system) + + Values are defined in: + - `include/linux/reboot.h` (enum psc_reason) + +What: /sys/kernel/pscrr/reason_boot +Date: April 2025 +KernelVersion: 6.15 +Contact: Oleksij Rempel +Description: + This file provides the last recorded power state change reason + from before the current system boot. If a supported backend + (e.g., NVMEM) is configured, this value is retained across + reboots. + + Example usage (values are for illustration and may not reflect + actual reasons used in a given system): + Read: + $ cat /sys/kernel/pscrr/reason_boot + 2 # (Example: Over-temperature shutdown, may differ per system) + --=20 2.39.5