Re: [PATCH 1/7] drm/gem: Provide drm_gem_fb_{begin, end}_cpu_access() helpers

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@suse.de

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@ffwll.ch

-- 2.32.0