drm/fb_helper: Support framebuffers in I/O memory
At least sparc64 requires I/O-specific access to framebuffers. This patch updates the fbdev console accordingly. For drivers with direct access to the framebuffer memory, the callback functions in struct fb_ops test for the type of memory and call the rsp fb_sys_ of fb_cfb_ functions. Read and write operations are implemented internally by DRM's fbdev helper. For drivers that employ a shadow buffer, fbdev's blit function retrieves the framebuffer address as struct dma_buf_map, and uses dma_buf_map interfaces to access the buffer. The bochs driver on sparc64 uses a workaround to flag the framebuffer as I/O memory and avoid a HW exception. With the introduction of struct dma_buf_map, this is not required any longer. The patch removes the rsp code from both, bochs and fbdev. v7: * use min_t(size_t,) (kernel test robot) * return the number of bytes read/written, if any (fbdev testcase) v5: * implement fb_read/fb_write internally (Daniel, Sam) v4: * move dma_buf_map changes into separate patch (Daniel) * TODO list: comment on fbdev updates (Daniel) Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de> Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch> Reviewed-by: Sam Ravnborg <sam@ravnborg.org> Tested-by: Sam Ravnborg <sam@ravnborg.org> Link: https://patchwork.freedesktop.org/patch/msgid/20201103093015.1063-11-tzimmermann@suse.de
This commit is contained in:
Thomas Zimmermann
parent
b4e7090c24
commit
222ec45f4c
@ -201,13 +201,28 @@ Convert drivers to use drm_fbdev_generic_setup()
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------------------------------------------------
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Most drivers can use drm_fbdev_generic_setup(). Driver have to implement
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atomic modesetting and GEM vmap support. Current generic fbdev emulation
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expects the framebuffer in system memory (or system-like memory).
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atomic modesetting and GEM vmap support. Historically, generic fbdev emulation
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expected the framebuffer in system memory or system-like memory. By employing
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struct dma_buf_map, drivers with frambuffers in I/O memory can be supported
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as well.
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Contact: Maintainer of the driver you plan to convert
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Level: Intermediate
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Reimplement functions in drm_fbdev_fb_ops without fbdev
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-------------------------------------------------------
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A number of callback functions in drm_fbdev_fb_ops could benefit from
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being rewritten without dependencies on the fbdev module. Some of the
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helpers could further benefit from using struct dma_buf_map instead of
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raw pointers.
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Contact: Thomas Zimmermann <tzimmermann@suse.de>, Daniel Vetter
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Level: Advanced
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drm_framebuffer_funcs and drm_mode_config_funcs.fb_create cleanup
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-----------------------------------------------------------------
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@ -151,7 +151,6 @@ int bochs_kms_init(struct bochs_device *bochs)
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bochs->dev->mode_config.preferred_depth = 24;
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bochs->dev->mode_config.prefer_shadow = 0;
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bochs->dev->mode_config.prefer_shadow_fbdev = 1;
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bochs->dev->mode_config.fbdev_use_iomem = true;
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bochs->dev->mode_config.quirk_addfb_prefer_host_byte_order = true;
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bochs->dev->mode_config.funcs = &bochs_mode_funcs;
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@ -372,24 +372,22 @@ static void drm_fb_helper_resume_worker(struct work_struct *work)
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}
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static void drm_fb_helper_dirty_blit_real(struct drm_fb_helper *fb_helper,
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struct drm_clip_rect *clip)
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struct drm_clip_rect *clip,
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struct dma_buf_map *dst)
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{
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struct drm_framebuffer *fb = fb_helper->fb;
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unsigned int cpp = fb->format->cpp[0];
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size_t offset = clip->y1 * fb->pitches[0] + clip->x1 * cpp;
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void *src = fb_helper->fbdev->screen_buffer + offset;
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void *dst = fb_helper->buffer->map.vaddr + offset;
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size_t len = (clip->x2 - clip->x1) * cpp;
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unsigned int y;
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for (y = clip->y1; y < clip->y2; y++) {
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if (!fb_helper->dev->mode_config.fbdev_use_iomem)
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memcpy(dst, src, len);
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else
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memcpy_toio((void __iomem *)dst, src, len);
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dma_buf_map_incr(dst, offset); /* go to first pixel within clip rect */
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for (y = clip->y1; y < clip->y2; y++) {
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dma_buf_map_memcpy_to(dst, src, len);
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dma_buf_map_incr(dst, fb->pitches[0]);
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src += fb->pitches[0];
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dst += fb->pitches[0];
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}
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}
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@ -417,8 +415,9 @@ static void drm_fb_helper_dirty_work(struct work_struct *work)
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ret = drm_client_buffer_vmap(helper->buffer, &map);
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if (ret)
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return;
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drm_fb_helper_dirty_blit_real(helper, &clip_copy);
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drm_fb_helper_dirty_blit_real(helper, &clip_copy, &map);
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}
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if (helper->fb->funcs->dirty)
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helper->fb->funcs->dirty(helper->fb, NULL, 0, 0,
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&clip_copy, 1);
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@ -2027,6 +2026,199 @@ static int drm_fbdev_fb_mmap(struct fb_info *info, struct vm_area_struct *vma)
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return -ENODEV;
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}
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static bool drm_fbdev_use_iomem(struct fb_info *info)
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{
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struct drm_fb_helper *fb_helper = info->par;
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struct drm_client_buffer *buffer = fb_helper->buffer;
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return !drm_fbdev_use_shadow_fb(fb_helper) && buffer->map.is_iomem;
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}
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static ssize_t fb_read_screen_base(struct fb_info *info, char __user *buf, size_t count,
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loff_t pos)
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{
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const char __iomem *src = info->screen_base + pos;
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size_t alloc_size = min(count, PAGE_SIZE);
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ssize_t ret = 0;
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int err = 0;
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char *tmp;
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tmp = kmalloc(alloc_size, GFP_KERNEL);
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if (!tmp)
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return -ENOMEM;
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while (count) {
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size_t c = min_t(size_t, count, alloc_size);
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memcpy_fromio(tmp, src, c);
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if (copy_to_user(buf, tmp, c)) {
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err = -EFAULT;
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break;
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}
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src += c;
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buf += c;
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ret += c;
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count -= c;
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}
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kfree(tmp);
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return ret ? ret : err;
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}
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static ssize_t fb_read_screen_buffer(struct fb_info *info, char __user *buf, size_t count,
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loff_t pos)
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{
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const char *src = info->screen_buffer + pos;
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if (copy_to_user(buf, src, count))
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return -EFAULT;
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return count;
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}
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static ssize_t drm_fbdev_fb_read(struct fb_info *info, char __user *buf,
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size_t count, loff_t *ppos)
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{
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loff_t pos = *ppos;
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size_t total_size;
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ssize_t ret;
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if (info->screen_size)
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total_size = info->screen_size;
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else
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total_size = info->fix.smem_len;
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if (pos >= total_size)
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return 0;
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if (count >= total_size)
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count = total_size;
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if (total_size - count < pos)
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count = total_size - pos;
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if (drm_fbdev_use_iomem(info))
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ret = fb_read_screen_base(info, buf, count, pos);
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else
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ret = fb_read_screen_buffer(info, buf, count, pos);
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if (ret > 0)
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*ppos += ret;
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return ret;
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}
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static ssize_t fb_write_screen_base(struct fb_info *info, const char __user *buf, size_t count,
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loff_t pos)
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{
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char __iomem *dst = info->screen_base + pos;
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size_t alloc_size = min(count, PAGE_SIZE);
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ssize_t ret = 0;
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int err = 0;
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u8 *tmp;
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tmp = kmalloc(alloc_size, GFP_KERNEL);
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if (!tmp)
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return -ENOMEM;
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while (count) {
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size_t c = min_t(size_t, count, alloc_size);
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if (copy_from_user(tmp, buf, c)) {
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err = -EFAULT;
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break;
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}
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memcpy_toio(dst, tmp, c);
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dst += c;
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buf += c;
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ret += c;
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count -= c;
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}
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kfree(tmp);
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return ret ? ret : err;
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}
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static ssize_t fb_write_screen_buffer(struct fb_info *info, const char __user *buf, size_t count,
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loff_t pos)
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{
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char *dst = info->screen_buffer + pos;
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if (copy_from_user(dst, buf, count))
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return -EFAULT;
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return count;
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}
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static ssize_t drm_fbdev_fb_write(struct fb_info *info, const char __user *buf,
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size_t count, loff_t *ppos)
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{
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loff_t pos = *ppos;
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size_t total_size;
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ssize_t ret;
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int err = 0;
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if (info->screen_size)
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total_size = info->screen_size;
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else
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total_size = info->fix.smem_len;
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if (pos > total_size)
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return -EFBIG;
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if (count > total_size) {
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err = -EFBIG;
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count = total_size;
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}
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if (total_size - count < pos) {
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if (!err)
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err = -ENOSPC;
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count = total_size - pos;
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}
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/*
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* Copy to framebuffer even if we already logged an error. Emulates
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* the behavior of the original fbdev implementation.
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*/
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if (drm_fbdev_use_iomem(info))
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ret = fb_write_screen_base(info, buf, count, pos);
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else
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ret = fb_write_screen_buffer(info, buf, count, pos);
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if (ret > 0)
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*ppos += ret;
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return ret ? ret : err;
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}
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static void drm_fbdev_fb_fillrect(struct fb_info *info,
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const struct fb_fillrect *rect)
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{
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if (drm_fbdev_use_iomem(info))
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drm_fb_helper_cfb_fillrect(info, rect);
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else
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drm_fb_helper_sys_fillrect(info, rect);
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}
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static void drm_fbdev_fb_copyarea(struct fb_info *info,
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const struct fb_copyarea *area)
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{
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if (drm_fbdev_use_iomem(info))
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drm_fb_helper_cfb_copyarea(info, area);
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else
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drm_fb_helper_sys_copyarea(info, area);
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}
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static void drm_fbdev_fb_imageblit(struct fb_info *info,
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const struct fb_image *image)
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{
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if (drm_fbdev_use_iomem(info))
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drm_fb_helper_cfb_imageblit(info, image);
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else
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drm_fb_helper_sys_imageblit(info, image);
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}
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static const struct fb_ops drm_fbdev_fb_ops = {
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.owner = THIS_MODULE,
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DRM_FB_HELPER_DEFAULT_OPS,
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@ -2034,11 +2226,11 @@ static const struct fb_ops drm_fbdev_fb_ops = {
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.fb_release = drm_fbdev_fb_release,
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.fb_destroy = drm_fbdev_fb_destroy,
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.fb_mmap = drm_fbdev_fb_mmap,
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.fb_read = drm_fb_helper_sys_read,
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.fb_write = drm_fb_helper_sys_write,
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.fb_fillrect = drm_fb_helper_sys_fillrect,
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.fb_copyarea = drm_fb_helper_sys_copyarea,
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.fb_imageblit = drm_fb_helper_sys_imageblit,
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.fb_read = drm_fbdev_fb_read,
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.fb_write = drm_fbdev_fb_write,
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.fb_fillrect = drm_fbdev_fb_fillrect,
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.fb_copyarea = drm_fbdev_fb_copyarea,
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.fb_imageblit = drm_fbdev_fb_imageblit,
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};
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static struct fb_deferred_io drm_fbdev_defio = {
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@ -877,18 +877,6 @@ struct drm_mode_config {
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*/
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bool prefer_shadow_fbdev;
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/**
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* @fbdev_use_iomem:
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*
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* Set to true if framebuffer reside in iomem.
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* When set to true memcpy_toio() is used when copying the framebuffer in
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* drm_fb_helper.drm_fb_helper_dirty_blit_real().
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*
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* FIXME: This should be replaced with a per-mapping is_iomem
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* flag (like ttm does), and then used everywhere in fbdev code.
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*/
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bool fbdev_use_iomem;
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/**
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* @quirk_addfb_prefer_xbgr_30bpp:
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*
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