[PATCH] drm/panthor: Fix the FW reset logic

[Boris Brezillon]

On Tue, 30 Apr 2024 13:37:27 +0200
Boris Brezillon <boris.brezillon at collabora.com> wrote:

> In the post_reset function, if the fast reset didn't succeed, we
> are not clearing the fast_reset flag, which prevents firmware
> sections from being reloaded. While at it, use panthor_fw_stop()
> instead of manually writing DISABLE to the MCU_CONTROL register.
> 
> Fixes: 2718d91816ee ("drm/panthor: Add the FW logical block")
> Signed-off-by: Boris Brezillon <boris.brezillon at collabora.com>

Queued to drm-misc-next-fixes.

> ---
>  drivers/gpu/drm/panthor/panthor_fw.c | 7 ++++---
>  1 file changed, 4 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/gpu/drm/panthor/panthor_fw.c b/drivers/gpu/drm/panthor/panthor_fw.c
> index 181395e2859a..fedf9627453f 100644
> --- a/drivers/gpu/drm/panthor/panthor_fw.c
> +++ b/drivers/gpu/drm/panthor/panthor_fw.c
> @@ -1083,10 +1083,11 @@ int panthor_fw_post_reset(struct panthor_device *ptdev)
>  		if (!ret)
>  			goto out;
>  
> -		/* Force a disable, so we get a fresh boot on the next
> -		 * panthor_fw_start() call.
> +		/* Forcibly reset the MCU and force a slow reset, so we get a
> +		 * fresh boot on the next panthor_fw_start() call.
>  		 */
> -		gpu_write(ptdev, MCU_CONTROL, MCU_CONTROL_DISABLE);
> +		panthor_fw_stop(ptdev);
> +		ptdev->fw->fast_reset = false;
>  		drm_err(&ptdev->base, "FW fast reset failed, trying a slow reset");
>  	}
>