On Wed, Apr 06, 2022 at 03:47:11PM -0400, Tom Rini wrote:
On Tue, Mar 29, 2022 at 04:16:53PM +0100, abdellatif.elkhlifi@arm.com wrote:
From: Abdellatif El Khlifi abdellatif.elkhlifi@arm.com
This patchset adds support for Arm FF-A (Arm Firmware Framework for Armv8-A v1.0).
FF-A support is generic by design and can be used by any Arm platform.
The features added are as follows:
1/ FF-A device driver 2/ armffa command 3/ FF-A Sandbox driver 4/ FF-A Sandbox test cases 5/ FF-A MM communication
The suggested design sees FF-A as a data bus allowing data exchange with the firmware running under TrustZone HW (such as Optee). The same approach was followed in the FF-A driver in Linux kernel (https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/driv...))
u-boot boards using FF-A can provide a device tree node in a <board>-u-boot.dtsi file. Since the node can not be hosted in Linux device tree, we suggest using u-boot device tree.
Why can't the node be in the upstream tree? It should be, so that it can be shared between all users. Especially since there's in-Linux users?
-- Tom
Linux already has an FF-A bus driver and doesn't use a device tree node for FF-A.
The Linux driver registers FF-A as a bus:
int arm_ffa_bus_init(void) { return bus_register(&ffa_bus_type); }
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/driv...
So, there is no user for the node in Linux. That's why we suggest hosting the node in the u-boot device tree (a u-boot.dtsi file)