Re: [PATCH 6/9] drm/panfrost: Add "clean only safe" feature bit

[Steven Price <steven.price@arm.com>]

On 11/02/2022 20:27, alyssa.rosenzweig@collabora.com wrote:
> From: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
> 
> Add the HW_FEATURE_CLEAN_ONLY_SAFE bit based on kbase. When I actually
> tried to port the logic from kbase, trivial jobs raised Data Invalid
> Faults, so this may depend on other coherency details. It's still useful
> to have the bit to record the feature bit when adding new models.
> 
> Signed-off-by: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>

Reviewed-by: Steven Price <steven.price@arm.com>

Sadly I don't have the hardware to try this out on, but it should be a
simple case of the below (untested):

----8<----
diff --git a/drivers/gpu/drm/panfrost/panfrost_job.c b/drivers/gpu/drm/panfrost/panfrost_job.c
index 908d79520853..602e51c4966e 100644
--- a/drivers/gpu/drm/panfrost/panfrost_job.c
+++ b/drivers/gpu/drm/panfrost/panfrost_job.c
@@ -212,9 +212,13 @@ static void panfrost_job_hw_submit(struct panfrost_job *job, int js)
         * start */
        cfg |= JS_CONFIG_THREAD_PRI(8) |
                JS_CONFIG_START_FLUSH_CLEAN_INVALIDATE |
-               JS_CONFIG_END_FLUSH_CLEAN_INVALIDATE |
                panfrost_get_job_chain_flag(job);
 
+       if (panfrost_has_hw_feature(pfdev, HW_FEATURE_CLEAN_ONLY_SAFE))
+               cfg |= JS_CONFIG_END_FLUSH_CLEAN;
+       else
+               cfg |= JS_CONFIG_END_FLUSH_CLEAN_INVALIDATE;
+
        if (panfrost_has_hw_feature(pfdev, HW_FEATURE_FLUSH_REDUCTION))
                cfg |= JS_CONFIG_ENABLE_FLUSH_REDUCTION;
 
----8<----

Steve

> ---
>  drivers/gpu/drm/panfrost/panfrost_features.h | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/gpu/drm/panfrost/panfrost_features.h b/drivers/gpu/drm/panfrost/panfrost_features.h
> index 36fadcf9634e..1a8bdebc86a3 100644
> --- a/drivers/gpu/drm/panfrost/panfrost_features.h
> +++ b/drivers/gpu/drm/panfrost/panfrost_features.h
> @@ -21,6 +21,7 @@ enum panfrost_hw_feature {
>  	HW_FEATURE_TLS_HASHING,
>  	HW_FEATURE_THREAD_GROUP_SPLIT,
>  	HW_FEATURE_IDVS_GROUP_SIZE,
> +	HW_FEATURE_CLEAN_ONLY_SAFE,
>  	HW_FEATURE_3BIT_EXT_RW_L2_MMU_CONFIG,
>  };
>