On 14/10/2025 10:43, Karunika Choo wrote:
> Split the GPU_ID register read into its own helper function. The GPU_ID
> value will be used to enable architecture-specific behaviours, which may
> also affect how other registers (such as those used for gpu_info) are
> read.
>
> This change separates the read operation so that subsequent code can
> depend on the intermediate result of processing the GPU_ID.
>
> Signed-off-by: Karunika Choo <karunika.choo@arm.com>
I'd be very tempted to squash this into the next commit and simple read
the GPU ID at the beginning of panthor_hw_bind_device(). Is there any
reason not to?
Steve
> ---
> drivers/gpu/drm/panthor/panthor_hw.c | 16 +++++++++++++++-
> 1 file changed, 15 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/panthor/panthor_hw.c b/drivers/gpu/drm/panthor/panthor_hw.c
> index 4f2858114e5e..326a9db0b5c2 100644
> --- a/drivers/gpu/drm/panthor/panthor_hw.c
> +++ b/drivers/gpu/drm/panthor/panthor_hw.c
> @@ -62,7 +62,6 @@ static void panthor_gpu_info_init(struct panthor_device *ptdev)
> {
> unsigned int i;
>
> - ptdev->gpu_info.gpu_id = gpu_read(ptdev, GPU_ID);
> ptdev->gpu_info.csf_id = gpu_read(ptdev, GPU_CSF_ID);
> ptdev->gpu_info.gpu_rev = gpu_read(ptdev, GPU_REVID);
> ptdev->gpu_info.core_features = gpu_read(ptdev, GPU_CORE_FEATURES);
> @@ -117,8 +116,23 @@ static void panthor_hw_info_init(struct panthor_device *ptdev)
> ptdev->gpu_info.tiler_present);
> }
>
> +static int panthor_hw_gpu_id_init(struct panthor_device *ptdev)
> +{
> + ptdev->gpu_info.gpu_id = gpu_read(ptdev, GPU_ID);
> + if (!ptdev->gpu_info.gpu_id)
> + return -ENXIO;
> +
> + return 0;
> +}
> +
> int panthor_hw_init(struct panthor_device *ptdev)
> {
> + int ret = 0;
> +
> + ret = panthor_hw_gpu_id_init(ptdev);
> + if (ret)
> + return ret;
> +
> panthor_hw_info_init(ptdev);
>
> return 0;