Commit 37408cd8 authored by Thomas Zimmermann's avatar Thomas Zimmermann
Browse files

drm/gem: Provide drm_gem_fb_{begin,end}_cpu_access() helpers 



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.

v2:
	* fix typo in docs (Daniel)

Signed-off-by: default avatarThomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: default avatarNoralf Trønnes <noralf@tronnes.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20210716140801.1215-2-tzimmermann@suse.de
parent a791cde6

drivers/gpu/drm/drm_gem_framebuffer_helper.c

+89 −0
Original line number Diff line number Diff line
@@ -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

 * 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

 * 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)

{

include/drm/drm_gem_framebuffer_helper.h

+6 −0
Original line number Diff line number Diff line 
#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))