On 15/10/2025 14:01, Boris Brezillon wrote:
> From: Faith Ekstrand <[email protected]>
>
> Will be used by the UMD to optimize CPU accesses to buffers
> that are frequently read by the CPU, or on which the access
> pattern makes non-cacheable mappings inefficient.
>
> Mapping buffers CPU-cached implies taking care of the CPU
> cache maintenance in the UMD, unless the GPU is IO coherent.
>
> v2:
> - Add more to the commit message
>
> v3:
> - No changes
>
> Signed-off-by: Faith Ekstrand <[email protected]>
> Signed-off-by: Boris Brezillon <[email protected]>
> ---
> drivers/gpu/drm/panfrost/panfrost_drv.c | 10 ++++++++--
> drivers/gpu/drm/panfrost/panfrost_gem.c | 3 +++
> include/uapi/drm/panfrost_drm.h | 1 +
> 3 files changed, 12 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/panfrost/panfrost_drv.c
> b/drivers/gpu/drm/panfrost/panfrost_drv.c
> index 00c0881fa2f0..0f51b1dc1abc 100644
> --- a/drivers/gpu/drm/panfrost/panfrost_drv.c
> +++ b/drivers/gpu/drm/panfrost/panfrost_drv.c
> @@ -125,6 +125,10 @@ static int panfrost_ioctl_get_param(struct drm_device
> *ddev, void *data, struct
> return 0;
> }
>
> +#define PANFROST_BO_FLAGS (PANFROST_BO_NOEXEC | \
> + PANFROST_BO_HEAP | \
> + PANFROST_BO_WB_MMAP)
> +
> static int panfrost_ioctl_create_bo(struct drm_device *dev, void *data,
> struct drm_file *file)
> {
> @@ -134,8 +138,7 @@ static int panfrost_ioctl_create_bo(struct drm_device
> *dev, void *data,
> struct panfrost_gem_mapping *mapping;
> int ret;
>
> - if (!args->size || args->pad ||
> - (args->flags & ~(PANFROST_BO_NOEXEC | PANFROST_BO_HEAP)))
> + if (!args->size || args->pad || (args->flags & ~PANFROST_BO_FLAGS))
> return -EINVAL;
>
> /* Heaps should never be executable */
> @@ -661,6 +664,9 @@ static int panfrost_ioctl_query_bo_info(struct drm_device
> *dev, void *data,
>
> if (bo->is_heap)
> args->create_flags |= PANFROST_BO_HEAP;
> +
> + if (bo->base.map_wc)
> + args->create_flags |= PANFROST_BO_WB_MMAP;
This test is still reversed (or I'm confused?)
Thanks,
Steve
> }
>
> drm_gem_object_put(gem_obj);
> diff --git a/drivers/gpu/drm/panfrost/panfrost_gem.c
> b/drivers/gpu/drm/panfrost/panfrost_gem.c
> index da0362202d94..0e8028ee9d1f 100644
> --- a/drivers/gpu/drm/panfrost/panfrost_gem.c
> +++ b/drivers/gpu/drm/panfrost/panfrost_gem.c
> @@ -320,6 +320,9 @@ panfrost_gem_create(struct drm_device *dev, size_t size,
> u32 flags)
> bo->noexec = !!(flags & PANFROST_BO_NOEXEC);
> bo->is_heap = !!(flags & PANFROST_BO_HEAP);
>
> + if (flags & PANFROST_BO_WB_MMAP)
> + bo->base.map_wc = false;
> +
> return bo;
> }
>
> diff --git a/include/uapi/drm/panfrost_drm.h b/include/uapi/drm/panfrost_drm.h
> index e7d01e744efd..244d2f96c2d7 100644
> --- a/include/uapi/drm/panfrost_drm.h
> +++ b/include/uapi/drm/panfrost_drm.h
> @@ -104,6 +104,7 @@ struct drm_panfrost_wait_bo {
> /* Valid flags to pass to drm_panfrost_create_bo */
> #define PANFROST_BO_NOEXEC 1
> #define PANFROST_BO_HEAP 2
> +#define PANFROST_BO_WB_MMAP 4
>
> /**
> * struct drm_panfrost_create_bo - ioctl argument for creating Panfrost BOs.
