What:		/sys/firmware/lfa
Date:		May 2026
Contact:	Andre Przywara <andre.przywara@arm.com>
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/<GUID>/activate
Date:		May 2026
Contact:	Andre Przywara <andre.przywara@arm.com>
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/<GUID>/activation_capable
Date:		May 2026
Contact:	Andre Przywara <andre.przywara@arm.com>
Description:
		(RO) A boolean value to show whether this firmware image is
		capable of being activated.

What:		/sys/firmware/lfa/<GUID>/auto_activate
Date:		May 2026
Contact:	Andre Przywara <andre.przywara@arm.com>
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/<GUID>/cancel
Date:		May 2026
Contact:	Andre Przywara <andre.przywara@arm.com>
Description:
		(WO) Write a boolean 'true' value to cancel a recently
		triggered activation, if that has not finished yet.

What:		/sys/firmware/lfa/<GUID>/cpu_rendezvous
Date:		May 2026
Contact:	Andre Przywara <andre.przywara@arm.com>
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/<GUID>/current_version
Date:		May 2026
Contact:	Andre Przywara <andre.przywara@arm.com>
Description:
		(RO) Shows the currently running version of that firmware
		image, as reported by the agent (if supported).

What:		/sys/firmware/lfa/<GUID>/force_cpu_rendezvous
Date:		May 2026
Contact:	Andre Przywara <andre.przywara@arm.com>
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/<GUID>/may_reset_cpu
Date:		May 2026
Contact:	Andre Przywara <andre.przywara@arm.com>
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/<GUID>/name
Date:		May 2026
Contact:	Andre Przywara <andre.przywara@arm.com>
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/<GUID>/pending_version
Date:		May 2026
Contact:	Andre Przywara <andre.przywara@arm.com>
Description:
		(RO) Shows the version number of a pending firmware update
		image, as reported by the agent (if supported).
