[PATCH] pmdomain: rockchip: Check if smcc could be handled by TA

[Steven Price]

On 19/02/2025 00:58, Shawn Lin wrote:
> Non-existent trusted-firmware could lead smcc calls into some
> unset location which breaks the system.
> 
> Reported-by: Steven Price <steven.price at arm.com>
> Cc: Steven Price <steven.price at arm.com>
> Suggested-by: Heiko Stuebner <heiko at sntech.de>
> Fixes: 58ebba35ddab ("pmdomain: rockchip: Add smc call to inform firmware")
> Signed-off-by: Shawn Lin <shawn.lin at rock-chips.com>

Tested-by: Steven Price <steven.price at arm.com>

Although one note below...

> ---
> Hi Ulf, this's a follow-up patch fixing the issue Steven saw.
> 
>  drivers/pmdomain/rockchip/pm-domains.c | 7 ++++---
>  1 file changed, 4 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/pmdomain/rockchip/pm-domains.c b/drivers/pmdomain/rockchip/pm-domains.c
> index 49842f1..27a5c68 100644
> --- a/drivers/pmdomain/rockchip/pm-domains.c
> +++ b/drivers/pmdomain/rockchip/pm-domains.c
> @@ -572,9 +572,10 @@ static void rockchip_do_pmu_set_power_domain(struct rockchip_pm_domain *pd,
>  	}
>  
>  	/* Inform firmware to keep this pd on or off */
> -	arm_smccc_smc(ROCKCHIP_SIP_SUSPEND_MODE, ROCKCHIP_SLEEP_PD_CONFIG,
> -			pmu->info->pwr_offset + pd_pwr_offset,
> -			pd->info->pwr_mask, on, 0, 0, 0, &res);
> +	if (arm_smccc_1_1_get_conduit() != SMCCC_CONDUIT_NONE)
> +		arm_smccc_smc(ROCKCHIP_SIP_SUSPEND_MODE, ROCKCHIP_SLEEP_PD_CONFIG,
> +				pmu->info->pwr_offset + pd_pwr_offset,
> +				pd->info->pwr_mask, on, 0, 0, 0, &res);

Note that if the conduit is SMCCC_CONDUIT_HVC then this will still
attempt an SMC. I'm not sure if this situation can happen in practice.

There is a (horrifyingly complex) macro arm_smccc_1_1_invoke() which
will automatically use the correct conduit, and even copes with the
SMCCC_CONDUIT_NONE case (by simply failing the call).

Steve

>  }
>  
>  static int rockchip_pd_power(struct rockchip_pm_domain *pd, bool power_on)