On Fri, Jul 16, 2021 at 04:07:55PM +0200, Thomas Zimmermann wrote:
> Implement helpers drm_gem_fb_begin_cpu_access() and _end_cpu_access(),
> which call the rsp dma-buf functions for all GEM BOs of the given
> framebuffer.
>
> Calls to dma_buf_end_cpu_access() can return an error code on failure,
> while drm_gem_fb_end_cpu_access() does not. The latter runs during DRM's
> atomic commit or during cleanup. Both cases don't allow for errors, so
> leave out the return value.
>
> Signed-off-by: Thomas Zimmermann <tzimmermann@xxxxxxx>
> ---
> drivers/gpu/drm/drm_gem_framebuffer_helper.c | 89 ++++++++++++++++++++
> include/drm/drm_gem_framebuffer_helper.h | 6 ++
> 2 files changed, 95 insertions(+)
>
> diff --git a/drivers/gpu/drm/drm_gem_framebuffer_helper.c b/drivers/gpu/drm/drm_gem_framebuffer_helper.c
> index e2c68822e05c..94a1c0b0edfd 100644
> --- a/drivers/gpu/drm/drm_gem_framebuffer_helper.c
> +++ b/drivers/gpu/drm/drm_gem_framebuffer_helper.c
> @@ -306,6 +306,95 @@ drm_gem_fb_create_with_dirty(struct drm_device *dev, struct drm_file *file,
> }
> EXPORT_SYMBOL_GPL(drm_gem_fb_create_with_dirty);
>
> +/**
> + * drm_gem_fb_begin_cpu_access - prepares GEM buffer objects for CPU access
> + * @fb: the framebuffer
> + * @dir: access mode
> + *
> + * Prepares a framebuffer'S GEM buffer objects for CPU access. This function
s/S/s/
> + * must be called before accessing the BO data within the kernel. For imported
> + * BOs, the function calls dma_buf_begin_cpu_access().
> + *
> + * See drm_gem_fb_end_cpu_access() for signalling the end of CPU access.
> + *
> + * Returns:
> + * 0 on success, or a negative errno code otherwise.
> + */
> +int drm_gem_fb_begin_cpu_access(struct drm_framebuffer *fb, enum dma_data_direction dir)
> +{
> + struct dma_buf_attachment *import_attach;
> + struct drm_gem_object *obj;
> + size_t i;
> + int ret, ret2;
> +
> + for (i = 0; i < ARRAY_SIZE(fb->obj); ++i) {
> + obj = drm_gem_fb_get_obj(fb, i);
> + if (!obj)
> + continue;
> + import_attach = obj->import_attach;
> + if (!import_attach)
> + continue;
> + ret = dma_buf_begin_cpu_access(import_attach->dmabuf, dir);
> + if (ret)
> + goto err_dma_buf_end_cpu_access;
> + }
> +
> + return 0;
> +
> +err_dma_buf_end_cpu_access:
> + while (i) {
> + --i;
> + obj = drm_gem_fb_get_obj(fb, i);
> + if (!obj)
> + continue;
> + import_attach = obj->import_attach;
> + if (!import_attach)
> + continue;
> + ret2 = dma_buf_end_cpu_access(import_attach->dmabuf, dir);
> + if (ret2) {
> + drm_err(fb->dev,
> + "dma_buf_end_cpu_access() failed during error handling: %d\n",
> + ret2);
> + }
> + }
> +
> + return ret;
> +}
> +EXPORT_SYMBOL(drm_gem_fb_begin_cpu_access);
> +
> +/**
> + * drm_gem_fb_end_cpu_access - signals end of CPU access to GEM buffer objects
> + * @fb: the framebuffer
> + * @dir: access mode
> + *
> + * Signals the end of CPU access to the given framebuffer'S GEM buffer objects. This
s/S/s/
> + * function must be paired with a corresponding call to drm_gem_fb_begin_cpu_access().
> + * For imported BOs, the function calls dma_buf_end_cpu_access().
> + *
> + * See also drm_gem_fb_begin_cpu_access().
> + */
> +void drm_gem_fb_end_cpu_access(struct drm_framebuffer *fb, enum dma_data_direction dir)
> +{
> + size_t i = ARRAY_SIZE(fb->obj);
> + struct dma_buf_attachment *import_attach;
> + struct drm_gem_object *obj;
> + int ret;
> +
> + while (i) {
> + --i;
> + obj = drm_gem_fb_get_obj(fb, i);
> + if (!obj)
> + continue;
> + import_attach = obj->import_attach;
> + if (!import_attach)
> + continue;
> + ret = dma_buf_end_cpu_access(import_attach->dmabuf, dir);
> + if (ret)
> + drm_err(fb->dev, "dma_buf_end_cpu_access() failed: %d\n", ret);
> + }
> +}
> +EXPORT_SYMBOL(drm_gem_fb_end_cpu_access);
> +
> static __u32 drm_gem_afbc_get_bpp(struct drm_device *dev,
> const struct drm_mode_fb_cmd2 *mode_cmd)
> {
> diff --git a/include/drm/drm_gem_framebuffer_helper.h b/include/drm/drm_gem_framebuffer_helper.h
> index 6bdffc7aa124..5705722f0855 100644
> --- a/include/drm/drm_gem_framebuffer_helper.h
> +++ b/include/drm/drm_gem_framebuffer_helper.h
> @@ -1,6 +1,9 @@
> #ifndef __DRM_GEM_FB_HELPER_H__
> #define __DRM_GEM_FB_HELPER_H__
>
> +#include <linux/dma-buf.h>
> +#include <linux/dma-buf-map.h>
> +
> struct drm_afbc_framebuffer;
> struct drm_device;
> struct drm_fb_helper_surface_size;
> @@ -34,6 +37,9 @@ struct drm_framebuffer *
> drm_gem_fb_create_with_dirty(struct drm_device *dev, struct drm_file *file,
> const struct drm_mode_fb_cmd2 *mode_cmd);
>
> +int drm_gem_fb_begin_cpu_access(struct drm_framebuffer *fb, enum dma_data_direction dir);
> +void drm_gem_fb_end_cpu_access(struct drm_framebuffer *fb, enum dma_data_direction dir);
> +
> #define drm_is_afbc(modifier) \
> (((modifier) & AFBC_VENDOR_AND_TYPE_MASK) == DRM_FORMAT_MOD_ARM_AFBC(0))
Reviewed-by: Daniel Vetter <daniel.vetter@xxxxxxxx>
>
> --
> 2.32.0
>
--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
