[PATCH] drm/amdgpu: read reg in each iterate of psp_wait_for loop

[Huang Rui]

On Fri, Jul 14, 2017 at 06:20:17PM +0800, Junwei Zhang wrote:
> Signed-off-by: Junwei Zhang <Jerry.Zhang at amd.com>
> ---
>  drivers/gpu/drm/amd/amdgpu/amdgpu_psp.c | 3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_psp.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_psp.c
> index ba743d4..71ce3ee 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_psp.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_psp.c
> @@ -95,9 +95,8 @@ int psp_wait_for(struct psp_context *psp, uint32_t reg_index,
>  	int i;
>  	struct amdgpu_device *adev = psp->adev;
>  
> -	val = RREG32(reg_index);
> -
>  	for (i = 0; i < adev->usec_timeout; i++) {
> +		val = RREG32(reg_index);
>  		if (check_changed) {
>  			if (val != reg_val)
>  				return 0;

Nice catch. I remembered Ken also mentioned it before. This should fix the
issue I encountered before during bring-up. Can you open this handshake in
psp_v3_1_bootloader_load_sos and double check if this handshake is workable
with this fix. If yes, please add it back.

#if 0
        ret = psp_wait_for(psp, SOC15_REG_OFFSET(MP0, 0, mmMP0_SMN_C2PMSG_81),
                           RREG32_SOC15(MP0, 0, mmMP0_SMN_C2PMSG_81),
                           0, true);
#endif

Acked-by: Huang Rui <ray.huang at amd.com>