Commit a8595556 authored by Thomas Zimmermann's avatar Thomas Zimmermann
Browse files

drm/gem: Store client buffer mappings as struct dma_buf_map 



Kernel DRM clients now store their framebuffer address in an instance
of struct dma_buf_map. Depending on the buffer's location, the address
refers to system or I/O memory.

Callers of drm_client_buffer_vmap() receive a copy of the value in
the call's supplied arguments. It can be accessed and modified with
dma_buf_map interfaces.

v6:
	* don't call page_to_phys() on framebuffers in I/O memory;
	  warn instead (Daniel)

Signed-off-by: default avatarThomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
Tested-by: default avatarSam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20201103093015.1063-9-tzimmermann@suse.de
parent a745fb1c

drivers/gpu/drm/drm_client.c

+20 −14
Original line number Diff line number Diff line
@@ -235,7 +235,7 @@ static void drm_client_buffer_delete(struct drm_client_buffer *buffer) 
{

	struct drm_device *dev = buffer->client->dev;



	drm_gem_vunmap(buffer->gem, buffer->vaddr);

	drm_gem_vunmap(buffer->gem, &buffer->map);



	if (buffer->gem)

		drm_gem_object_put(buffer->gem);
@@ -291,25 +291,31 @@ drm_client_buffer_create(struct drm_client_dev *client, u32 width, u32 height, u 
/**

 * drm_client_buffer_vmap - Map DRM client buffer into address space

 * @buffer: DRM client buffer

 * @map_copy: Returns the mapped memory's address

 *

 * This function maps a client buffer into kernel address space. If the

 * buffer is already mapped, it returns the mapping's address.

 * buffer is already mapped, it returns the existing mapping's address.

 *

 * Client buffer mappings are not ref'counted. Each call to

 * drm_client_buffer_vmap() should be followed by a call to

 * drm_client_buffer_vunmap(); or the client buffer should be mapped

 * throughout its lifetime.

 *

 * The returned address is a copy of the internal value. In contrast to

 * other vmap interfaces, you don't need it for the client's vunmap

 * function. So you can modify it at will during blit and draw operations.

 *

 * Returns:

 *	The mapped memory's address

 *	0 on success, or a negative errno code otherwise.

 */

void *drm_client_buffer_vmap(struct drm_client_buffer *buffer)

int

drm_client_buffer_vmap(struct drm_client_buffer *buffer, struct dma_buf_map *map_copy)

{

	struct dma_buf_map map;

	struct dma_buf_map *map = &buffer->map;

	int ret;



	if (buffer->vaddr)

		return buffer->vaddr;

	if (dma_buf_map_is_set(map))

		goto out;



	/*

	 * FIXME: The dependency on GEM here isn't required, we could
@@ -319,13 +325,14 @@ void *drm_client_buffer_vmap(struct drm_client_buffer *buffer) 
	 * fd_install step out of the driver backend hooks, to make that

	 * final step optional for internal users.

	 */

	ret = drm_gem_vmap(buffer->gem, &map);

	ret = drm_gem_vmap(buffer->gem, map);

	if (ret)

		return ERR_PTR(ret);

		return ret;



	buffer->vaddr = map.vaddr;

out:

	*map_copy = *map;



	return map.vaddr;

	return 0;

}

EXPORT_SYMBOL(drm_client_buffer_vmap);
@@ -339,10 +346,9 @@ EXPORT_SYMBOL(drm_client_buffer_vmap); 
 */

void drm_client_buffer_vunmap(struct drm_client_buffer *buffer)

{

	struct dma_buf_map map = DMA_BUF_MAP_INIT_VADDR(buffer->vaddr);

	struct dma_buf_map *map = &buffer->map;



	drm_gem_vunmap(buffer->gem, &map);

	buffer->vaddr = NULL;

	drm_gem_vunmap(buffer->gem, map);

}

EXPORT_SYMBOL(drm_client_buffer_vunmap);

drivers/gpu/drm/drm_fb_helper.c

+21 −11
Original line number Diff line number Diff line
@@ -378,7 +378,7 @@ static void drm_fb_helper_dirty_blit_real(struct drm_fb_helper *fb_helper, 
	unsigned int cpp = fb->format->cpp[0];

	size_t offset = clip->y1 * fb->pitches[0] + clip->x1 * cpp;

	void *src = fb_helper->fbdev->screen_buffer + offset;

	void *dst = fb_helper->buffer->vaddr + offset;

	void *dst = fb_helper->buffer->map.vaddr + offset;

	size_t len = (clip->x2 - clip->x1) * cpp;

	unsigned int y;
@@ -400,7 +400,8 @@ static void drm_fb_helper_dirty_work(struct work_struct *work) 
	struct drm_clip_rect *clip = &helper->dirty_clip;

	struct drm_clip_rect clip_copy;

	unsigned long flags;

	void *vaddr;

	struct dma_buf_map map;

	int ret;



	spin_lock_irqsave(&helper->dirty_lock, flags);

	clip_copy = *clip;
@@ -413,8 +414,8 @@ static void drm_fb_helper_dirty_work(struct work_struct *work) 


		/* Generic fbdev uses a shadow buffer */

		if (helper->buffer) {

			vaddr = drm_client_buffer_vmap(helper->buffer);

			if (IS_ERR(vaddr))

			ret = drm_client_buffer_vmap(helper->buffer, &map);

			if (ret)

				return;

			drm_fb_helper_dirty_blit_real(helper, &clip_copy);

		}
@@ -2060,7 +2061,8 @@ static int drm_fb_helper_generic_probe(struct drm_fb_helper *fb_helper, 
	struct drm_framebuffer *fb;

	struct fb_info *fbi;

	u32 format;

	void *vaddr;

	struct dma_buf_map map;

	int ret;



	drm_dbg_kms(dev, "surface width(%d), height(%d) and bpp(%d)\n",

		    sizes->surface_width, sizes->surface_height,
@@ -2096,14 +2098,22 @@ static int drm_fb_helper_generic_probe(struct drm_fb_helper *fb_helper, 
		fb_deferred_io_init(fbi);

	} else {

		/* buffer is mapped for HW framebuffer */

		vaddr = drm_client_buffer_vmap(fb_helper->buffer);

		if (IS_ERR(vaddr))

			return PTR_ERR(vaddr);

		ret = drm_client_buffer_vmap(fb_helper->buffer, &map);

		if (ret)

			return ret;

		if (map.is_iomem)

			fbi->screen_base = map.vaddr_iomem;

		else

			fbi->screen_buffer = map.vaddr;



		fbi->screen_buffer = vaddr;

		/* Shamelessly leak the physical address to user-space */

		/*

		 * Shamelessly leak the physical address to user-space. As

		 * page_to_phys() is undefined for I/O memory, warn in this

		 * case.

		 */

#if IS_ENABLED(CONFIG_DRM_FBDEV_LEAK_PHYS_SMEM)

		if (drm_leak_fbdev_smem && fbi->fix.smem_start == 0)

		if (drm_leak_fbdev_smem && fbi->fix.smem_start == 0 &&

		    !drm_WARN_ON_ONCE(dev, map.is_iomem))

			fbi->fix.smem_start =

				page_to_phys(virt_to_page(fbi->screen_buffer));

#endif

include/drm/drm_client.h

+4 −3
Original line number Diff line number Diff line
@@ -3,6 +3,7 @@ 
#ifndef _DRM_CLIENT_H_

#define _DRM_CLIENT_H_



#include <linux/dma-buf-map.h>

#include <linux/lockdep.h>

#include <linux/mutex.h>

#include <linux/types.h>
@@ -141,9 +142,9 @@ struct drm_client_buffer { 
	struct drm_gem_object *gem;



	/**

	 * @vaddr: Virtual address for the buffer

	 * @map: Virtual address for the buffer

	 */

	void *vaddr;

	struct dma_buf_map map;



	/**

	 * @fb: DRM framebuffer
@@ -155,7 +156,7 @@ struct drm_client_buffer * 
drm_client_framebuffer_create(struct drm_client_dev *client, u32 width, u32 height, u32 format);

void drm_client_framebuffer_delete(struct drm_client_buffer *buffer);

int drm_client_framebuffer_flush(struct drm_client_buffer *buffer, struct drm_rect *rect);

void *drm_client_buffer_vmap(struct drm_client_buffer *buffer);

int drm_client_buffer_vmap(struct drm_client_buffer *buffer, struct dma_buf_map *map);

void drm_client_buffer_vunmap(struct drm_client_buffer *buffer);



int drm_client_modeset_create(struct drm_client_dev *client);