Hi Weizhao,
On Thu, Jan 25, 2024 at 02:05:00PM +0000, Weizhao Ouyang wrote:
> According to PSCI specification DEN0022F, PSCI_FEATURES is used to check
> whether the SMCCC is implemented by discovering SMCCC_VERSION.
>
> Signed-off-by: Weizhao Ouyang <o451686...@gmail.com>
> ---
> drivers/firmware/psci.c | 2 +-
> include/linux/arm-smccc.h | 1 +
> 2 files changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/firmware/psci.c b/drivers/firmware/psci.c
> index c6b9efab41..894be8128d 100644
> --- a/drivers/firmware/psci.c
> +++ b/drivers/firmware/psci.c
> @@ -135,7 +135,7 @@ static int bind_smccc_features(struct udevice *dev, int
> psci_method)
> PSCI_VERSION_MAJOR(psci_0_2_get_version()) == 0)
> return 0;
>
> - if (request_psci_features(ARM_SMCCC_ARCH_FEATURES) ==
> + if (request_psci_features(ARM_SMCCC_VERSION) ==
> PSCI_RET_NOT_SUPPORTED)
> return 0;
I suggest we add checks on the SMCCC version like this:
if SMCCC_VERSION >= 1.1
assume SMCCC_ARCH_FEATURES is supported
discover arch features and bind drivers/devices
else
error
For more details [1][2].
[1]: SMC Calling Convention 1.5
(https://developer.arm.com/documentation/den0028/latest/)
SMCCC_ARCH_FEATURES MANDATORY from SMCCC v1.1
The implementation of this function can be detected by checking the SMCCC
version. This function is mandatory
if SMCCC_VERSION indicates that version 1.1 or later is implemented.
[2]: Linux checks SMCCC v1.1:
https://elixir.bootlin.com/linux/latest/source/drivers/firmware/psci/psci.c#L597
Cheers,
Abdellatif
