From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id BDFC5C982DF for ; Fri, 18 Sep 2026 14:12:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:Cc:List-Subscribe: List-Help:List-Post:List-Archive:List-Unsubscribe:List-Id: Content-Transfer-Encoding:MIME-Version:References:In-Reply-To:Message-ID:Date :Subject:To:From:Reply-To:Content-Type:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=CSE0JYRQj4NzmdA+7zDUjSEatmRf5Q356HFaN2jwssg=; b=rx/56HQNhqALeu ywPLZbdAw3tdXMLDEfgkNR9qXOTvRKIMiSdBooGkaBkTs13MMTle44SWb2Tg/d4GVnHKUaPZW+iLs 1gltjY9/Zp83zVVCC1Hu5NsjFp/dBlTD0urZy8U/M1Sjsu6cEjZ6dgXqt/85IjOUkv79gJyPWOrHX U4rOV5w0wiCvGRPnPVtBKe1ys5TFfxLz5nnzRnHeuL0eM7OMBKW/VLwRdDrpWBVzWYCrOwLha4DAE QcCCZVruHReg36NFwLo6nuhpC85Nk/V0DdcK2EVPF5h5d4gWRmeeuZIbVUyJD5l5NEeE6VdNgP9xi 9dBWSOQDsWgTLSXuGfRA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1x7ZJm-0000000EfxK-34Kx; Fri, 18 Sep 2026 14:11:58 +0000 Received: from desiato.infradead.org ([2001:8b0:10b:1:d65d:64ff:fe57:4e05]) by bombadil.infradead.org with esmtps (Exim 4.99.1 #2 (Red Hat Linux)) id 1x7ZJg-0000000Eftj-2TE2 for linux-arm-kernel@bombadil.infradead.org; Fri, 18 Sep 2026 14:11:52 +0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=desiato.20200630; h=Content-Transfer-Encoding:MIME-Version :References:In-Reply-To:Message-ID:Date:Subject:Cc:To:From:Sender:Reply-To: Content-Type:Content-ID:Content-Description; bh=CSE0JYRQj4NzmdA+7zDUjSEatmRf5Q356HFaN2jwssg=; b=gsv9RbYsiO+PzriUQ99YNx/TM/ a+pHUOYWFOBY8iF7uGRBEiDQM/mP0pG54Alv4/yzIQsHp9rL1Lg8+wotX7HLiym/GRn+sH4HxTBu6 AD9i8dxNj5iHbmb88MLkui8ZSXRWecUDqSbFMmWD8vLLpNGrjbPbmT7AoQoTE2x1Y3yMUsvqOAo2Q exFWS2HCBBtdzxZlhdU4jePMcA6mB6aYXzwR6ml+S/7WIrQ/PyQnf5xwlocjokNDlkJpDnukO1AmG u5QrMLeGU3IVivZO9n7ZWMqLdry2O/rOB/hN3nK1qNOehsrBvIOdjKUkoAxHI4R3W58aRkS9jKcj1 7O4KWwmA==; Received: from foss.arm.com ([217.140.110.172]) by desiato.infradead.org with esmtp (Exim 4.99.2 #2 (Red Hat Linux)) id 1x7ZJd-0000000ABfM-2mnb for linux-arm-kernel@lists.infradead.org; Fri, 18 Sep 2026 14:11:51 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id CF94F1D14; Fri, 18 Sep 2026 07:11:44 -0700 (PDT) Received: from e142021.Arm.com (e142021.arm.com [10.41.4.144]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id B6D673F86C; Fri, 18 Sep 2026 07:11:45 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1789740708; bh=h3MfiV0woiOCQI6Gw/byJn2fJjYmiAn1DfvOYZgNqro=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=U9bvvXF6jmRsyhz8nEU6QFc31N3ZiSYUbdjdttMs+pbLAuDkT1znSBQoHYBjbLq9Z gzMvjG1K522CWrnMwQAU+Z0ud/pY3cbRJzBvBKDBBoj1ThSuQ7XOj5IwCHddc/+Bi2 M8nRY8fwe7qnwLpEXSaZu0WX01m4LsW1fzaZg3yQ= From: Andre Przywara To: Mark Rutland , Lorenzo Pieralisi , Sudeep Holla Subject: [PATCH v4 8/8] firmware: smccc: lfa: add sysfs ABI documentation Date: Fri, 18 Sep 2026 16:11:11 +0200 Message-ID: <20260918141112.2115555-9-andre.przywara@arm.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260918141112.2115555-1-andre.przywara@arm.com> References: <20260918141112.2115555-1-andre.przywara@arm.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260918_151150_061300_4D179D1F X-CRM114-Status: GOOD ( 22.33 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Conor Dooley , vsethi@nvidia.com, Salman Nabi , Rob Herring , linux-kernel@vger.kernel.org, Varun Wadekar , Trilok Soni , devicetree@vger.kernel.org, Nirmoy Das , Krzysztof Kozlowski , linux-arm-kernel@lists.infradead.org Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Document the sysfs attribute files as exported by the LFA driver. Signed-off-by: Andre Przywara --- Documentation/ABI/testing/sysfs-firmware-lfa | 106 +++++++++++++++++++ 1 file changed, 106 insertions(+) create mode 100644 Documentation/ABI/testing/sysfs-firmware-lfa diff --git a/Documentation/ABI/testing/sysfs-firmware-lfa b/Documentation/ABI/testing/sysfs-firmware-lfa new file mode 100644 index 0000000000000..afd349af9cf14 --- /dev/null +++ b/Documentation/ABI/testing/sysfs-firmware-lfa @@ -0,0 +1,106 @@ +What: /sys/firmware/lfa +Date: May 2026 +Contact: Andre Przywara +Description: + The Arm Live Firmware Activation (LFA) spec describes an + interface between platform firmware (an agent) and any user + on the non-secure side (like the Linux kernel) to activate + pending firmware updates at runtime. The actual firmware + update would be provided independently (out-of-band, or + via any existing explicit firmware update mechanisms), then, + if supported, can be activated immediately, without rebooting + the system. + This directory contains one directory for each of the LFA + capable firmware images supported by the agent, identified by + its GUID. Within each directory, the same set of sysfs files + provides access to the properties and actions for this + particular firmware image. + +What: /sys/firmware/lfa//activate +Date: May 2026 +Contact: Andre Przywara +Description: + (WO) Write a boolean 'true' value to trigger the + activation of that firmware component. An update must be + pending for this to be successful. + +What: /sys/firmware/lfa//activation_capable +Date: May 2026 +Contact: Andre Przywara +Description: + (RO) A boolean value to show whether this firmware image is + capable of being activated. + +What: /sys/firmware/lfa//auto_activate +Date: May 2026 +Contact: Andre Przywara +Description: + (RW) Write a boolean 'true' value to allow a firmware image + to be automatically activated once a new firmware update + becomes available ("pending"). This depends on a working + notification scheme, for instance via an ACPI notification + or an interrupt to notify the kernel. + +What: /sys/firmware/lfa//cancel +Date: May 2026 +Contact: Andre Przywara +Description: + (WO) Write a boolean 'true' value to cancel a recently + triggered activation, if that has not finished yet. + +What: /sys/firmware/lfa//cpu_rendezvous +Date: May 2026 +Contact: Andre Przywara +Description: + (RO) A boolean value to show whether this image requires + a CPU rendezvous in firmware to be activated. If true, this + means all CPUs will enter the firmware during the activation + process, so will not be able to execute kernel code or + handle interrupts for a brief moment. + +What: /sys/firmware/lfa//current_version +Date: May 2026 +Contact: Andre Przywara +Description: + (RO) Shows the currently running version of that firmware + image, as reported by the agent (if supported). + +What: /sys/firmware/lfa//force_cpu_rendezvous +Date: May 2026 +Contact: Andre Przywara +Description: + (RW) Write a boolean 'true' value to force whether the kernel + will perform a CPU rendezvous during activation. This has no + effect if the firmware already *requires* a CPU rendezvous. + Firmware images might provide services to the kernel, at which + point is might be unsafe to continue running the kernel while + the activation is performed. Sending all CPUs into firmware + provides the safest option for the kernel. If you know for + certain that there are no services provides by that component + or the firmware component can handle requests during the + activation, you can write a 0 in here to avoid the brief + kernel downtime. + +What: /sys/firmware/lfa//may_reset_cpu +Date: May 2026 +Contact: Andre Przywara +Description: + (RO) A boolean value to show whether this firmware image + requires a CPU reset during the activation. + Currently this type of firmware image is not supported by + the kernel driver, as we cannot handle a CPU reset yet. + +What: /sys/firmware/lfa//name +Date: May 2026 +Contact: Andre Przywara +Description: + (RO) Shows a human readable name for that firmware image, if + known. Depends on the kernel driver knowing this particular + GUID, via a built-in list. + +What: /sys/firmware/lfa//pending_version +Date: May 2026 +Contact: Andre Przywara +Description: + (RO) Shows the version number of a pending firmware update + image, as reported by the agent (if supported). -- 2.43.0