linux-kernel - [PATCH 0/2] Arm LFA: timeout and ACPI platform driver support

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Message-ID: <20260210224023.2341728-1-vvidwans@nvidia.com>
Date: Tue, 10 Feb 2026 22:40:21 +0000
From: Vedashree Vidwans <vvidwans@...dia.com>
To: <salman.nabi@....com>, <sudeep.holla@....com>, <andre.przywara@....com>,
	<lpieralisi@...nel.org>, <mark.rutland@....com>,
	<trilokkumar.soni@....qualcomm.com>
CC: <ardb@...nel.org>, <chao.gao@...el.com>,
	<linux-arm-kernel@...ts.infradead.org>, <linux-coco@...ts.linux.dev>,
	<linux-kernel@...r.kernel.org>, <sdonthineni@...dia.com>,
	<vsethi@...dia.com>, <vwadekar@...dia.com>, Vedashree Vidwans
	<vvidwans@...dia.com>
Subject: [PATCH 0/2] Arm LFA: timeout and ACPI platform driver support

Hello,

(This is an updated version of the [RFC PATCH 0/5] Arm LFA: Improvements
and interrupt support [1], which builds on top of the latest [PATCH 0/1]
Arm Live Firmware activation (LFA) support [2].)

The latest LFA specification [3] updates the interface requirements for
ACPI-based platforms to use the ACPI Notify() signal, and
device-tree-based interface is unspecified. This series focuses on
reworking the LFA driver as an ACPI-backed platform driver, using ACPI
Notify() instead of a dedicated interrupt handler. The LFA core behavior
and sysfs layout remain as implemented by the base driver.

This series contains two incremental changes:
 1. Add a timeout and watchdog touch during LFA operations, to make the
driver more robust in cases where firmware-side prime/activation phases
take longer than expected. 
 2. Register the LFA implementation as a platform driver, layering a
platform driver interface on top of the existing LFA core logic so the
functionality can be instantiated via a platform device. 

Note:
This posting focuses on architectural and implementation improvements
for the LFA driver itself. It assumes that the bugs and issues raised
during review of the original "[PATCH 0/1] Arm Live Firmware activation
(LFA) support” [2] will be addressed directly by the author in that base
series. Once those fixes are in place, this series is intended to layer
on top cleanly.

Testing:
The final integrated driver (base LFA + these additions) has been tested
on Nvidia server platform with Linux kernel v6.16. The sysfs interface
was not exercised as part of this testing. 

Regards,
Veda

[1] https://lore.kernel.org/linux-arm-kernel/20251208221319.1524888-1-vvidwans@nvidia.com/
[2] https://lore.kernel.org/linux-arm-kernel/20260119122729.287522-2-salman.nabi@arm.com/
[3] https://developer.arm.com/documentation/den0147/latest/

Vedashree Vidwans (2):
  firmware: smccc: add timeout, touch wdt
  firmware: smccc: register as platform driver

 drivers/firmware/smccc/lfa_fw.c | 193 ++++++++++++++++++++++++++++----
 1 file changed, 174 insertions(+), 19 deletions(-)

-- 
2.43.0