From: Thomas Zimmermann Date: Tue, 3 Nov 2020 09:30:15 +0000 (+0100) Subject: drm/fb_helper: Support framebuffers in I/O memory X-Git-Tag: accepted/tizen/unified/20230118.172025~6402^2~28^2~1464 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=222ec45f4c69dfa8cd02c72928147ac06dffffa2;p=platform%2Fkernel%2Flinux-rpi.git 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 Reviewed-by: Daniel Vetter Reviewed-by: Sam Ravnborg Tested-by: Sam Ravnborg Link: https://patchwork.freedesktop.org/patch/msgid/20201103093015.1063-11-tzimmermann@suse.de --- diff --git a/Documentation/gpu/todo.rst b/Documentation/gpu/todo.rst index 59f63f1..acca232 100644 --- a/Documentation/gpu/todo.rst +++ b/Documentation/gpu/todo.rst @@ -201,13 +201,28 @@ Convert drivers to use drm_fbdev_generic_setup() ------------------------------------------------ Most drivers can use drm_fbdev_generic_setup(). Driver have to implement -atomic modesetting and GEM vmap support. Current generic fbdev emulation -expects the framebuffer in system memory (or system-like memory). +atomic modesetting and GEM vmap support. Historically, generic fbdev emulation +expected the framebuffer in system memory or system-like memory. By employing +struct dma_buf_map, drivers with frambuffers in I/O memory can be supported +as well. Contact: Maintainer of the driver you plan to convert Level: Intermediate +Reimplement functions in drm_fbdev_fb_ops without fbdev +------------------------------------------------------- + +A number of callback functions in drm_fbdev_fb_ops could benefit from +being rewritten without dependencies on the fbdev module. Some of the +helpers could further benefit from using struct dma_buf_map instead of +raw pointers. + +Contact: Thomas Zimmermann , Daniel Vetter + +Level: Advanced + + drm_framebuffer_funcs and drm_mode_config_funcs.fb_create cleanup ----------------------------------------------------------------- diff --git a/drivers/gpu/drm/bochs/bochs_kms.c b/drivers/gpu/drm/bochs/bochs_kms.c index 13d0d04..853081d 100644 --- a/drivers/gpu/drm/bochs/bochs_kms.c +++ b/drivers/gpu/drm/bochs/bochs_kms.c @@ -151,7 +151,6 @@ int bochs_kms_init(struct bochs_device *bochs) bochs->dev->mode_config.preferred_depth = 24; bochs->dev->mode_config.prefer_shadow = 0; bochs->dev->mode_config.prefer_shadow_fbdev = 1; - bochs->dev->mode_config.fbdev_use_iomem = true; bochs->dev->mode_config.quirk_addfb_prefer_host_byte_order = true; bochs->dev->mode_config.funcs = &bochs_mode_funcs; diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c index a0d8813..01ba1da 100644 --- a/drivers/gpu/drm/drm_fb_helper.c +++ b/drivers/gpu/drm/drm_fb_helper.c @@ -372,24 +372,22 @@ static void drm_fb_helper_resume_worker(struct work_struct *work) } static void drm_fb_helper_dirty_blit_real(struct drm_fb_helper *fb_helper, - struct drm_clip_rect *clip) + struct drm_clip_rect *clip, + struct dma_buf_map *dst) { struct drm_framebuffer *fb = fb_helper->fb; 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->map.vaddr + offset; size_t len = (clip->x2 - clip->x1) * cpp; unsigned int y; - for (y = clip->y1; y < clip->y2; y++) { - if (!fb_helper->dev->mode_config.fbdev_use_iomem) - memcpy(dst, src, len); - else - memcpy_toio((void __iomem *)dst, src, len); + dma_buf_map_incr(dst, offset); /* go to first pixel within clip rect */ + for (y = clip->y1; y < clip->y2; y++) { + dma_buf_map_memcpy_to(dst, src, len); + dma_buf_map_incr(dst, fb->pitches[0]); src += fb->pitches[0]; - dst += fb->pitches[0]; } } @@ -417,8 +415,9 @@ static void drm_fb_helper_dirty_work(struct work_struct *work) ret = drm_client_buffer_vmap(helper->buffer, &map); if (ret) return; - drm_fb_helper_dirty_blit_real(helper, &clip_copy); + drm_fb_helper_dirty_blit_real(helper, &clip_copy, &map); } + if (helper->fb->funcs->dirty) helper->fb->funcs->dirty(helper->fb, NULL, 0, 0, &clip_copy, 1); @@ -2027,6 +2026,199 @@ static int drm_fbdev_fb_mmap(struct fb_info *info, struct vm_area_struct *vma) return -ENODEV; } +static bool drm_fbdev_use_iomem(struct fb_info *info) +{ + struct drm_fb_helper *fb_helper = info->par; + struct drm_client_buffer *buffer = fb_helper->buffer; + + return !drm_fbdev_use_shadow_fb(fb_helper) && buffer->map.is_iomem; +} + +static ssize_t fb_read_screen_base(struct fb_info *info, char __user *buf, size_t count, + loff_t pos) +{ + const char __iomem *src = info->screen_base + pos; + size_t alloc_size = min(count, PAGE_SIZE); + ssize_t ret = 0; + int err = 0; + char *tmp; + + tmp = kmalloc(alloc_size, GFP_KERNEL); + if (!tmp) + return -ENOMEM; + + while (count) { + size_t c = min_t(size_t, count, alloc_size); + + memcpy_fromio(tmp, src, c); + if (copy_to_user(buf, tmp, c)) { + err = -EFAULT; + break; + } + + src += c; + buf += c; + ret += c; + count -= c; + } + + kfree(tmp); + + return ret ? ret : err; +} + +static ssize_t fb_read_screen_buffer(struct fb_info *info, char __user *buf, size_t count, + loff_t pos) +{ + const char *src = info->screen_buffer + pos; + + if (copy_to_user(buf, src, count)) + return -EFAULT; + + return count; +} + +static ssize_t drm_fbdev_fb_read(struct fb_info *info, char __user *buf, + size_t count, loff_t *ppos) +{ + loff_t pos = *ppos; + size_t total_size; + ssize_t ret; + + if (info->screen_size) + total_size = info->screen_size; + else + total_size = info->fix.smem_len; + + if (pos >= total_size) + return 0; + if (count >= total_size) + count = total_size; + if (total_size - count < pos) + count = total_size - pos; + + if (drm_fbdev_use_iomem(info)) + ret = fb_read_screen_base(info, buf, count, pos); + else + ret = fb_read_screen_buffer(info, buf, count, pos); + + if (ret > 0) + *ppos += ret; + + return ret; +} + +static ssize_t fb_write_screen_base(struct fb_info *info, const char __user *buf, size_t count, + loff_t pos) +{ + char __iomem *dst = info->screen_base + pos; + size_t alloc_size = min(count, PAGE_SIZE); + ssize_t ret = 0; + int err = 0; + u8 *tmp; + + tmp = kmalloc(alloc_size, GFP_KERNEL); + if (!tmp) + return -ENOMEM; + + while (count) { + size_t c = min_t(size_t, count, alloc_size); + + if (copy_from_user(tmp, buf, c)) { + err = -EFAULT; + break; + } + memcpy_toio(dst, tmp, c); + + dst += c; + buf += c; + ret += c; + count -= c; + } + + kfree(tmp); + + return ret ? ret : err; +} + +static ssize_t fb_write_screen_buffer(struct fb_info *info, const char __user *buf, size_t count, + loff_t pos) +{ + char *dst = info->screen_buffer + pos; + + if (copy_from_user(dst, buf, count)) + return -EFAULT; + + return count; +} + +static ssize_t drm_fbdev_fb_write(struct fb_info *info, const char __user *buf, + size_t count, loff_t *ppos) +{ + loff_t pos = *ppos; + size_t total_size; + ssize_t ret; + int err = 0; + + if (info->screen_size) + total_size = info->screen_size; + else + total_size = info->fix.smem_len; + + if (pos > total_size) + return -EFBIG; + if (count > total_size) { + err = -EFBIG; + count = total_size; + } + if (total_size - count < pos) { + if (!err) + err = -ENOSPC; + count = total_size - pos; + } + + /* + * Copy to framebuffer even if we already logged an error. Emulates + * the behavior of the original fbdev implementation. + */ + if (drm_fbdev_use_iomem(info)) + ret = fb_write_screen_base(info, buf, count, pos); + else + ret = fb_write_screen_buffer(info, buf, count, pos); + + if (ret > 0) + *ppos += ret; + + return ret ? ret : err; +} + +static void drm_fbdev_fb_fillrect(struct fb_info *info, + const struct fb_fillrect *rect) +{ + if (drm_fbdev_use_iomem(info)) + drm_fb_helper_cfb_fillrect(info, rect); + else + drm_fb_helper_sys_fillrect(info, rect); +} + +static void drm_fbdev_fb_copyarea(struct fb_info *info, + const struct fb_copyarea *area) +{ + if (drm_fbdev_use_iomem(info)) + drm_fb_helper_cfb_copyarea(info, area); + else + drm_fb_helper_sys_copyarea(info, area); +} + +static void drm_fbdev_fb_imageblit(struct fb_info *info, + const struct fb_image *image) +{ + if (drm_fbdev_use_iomem(info)) + drm_fb_helper_cfb_imageblit(info, image); + else + drm_fb_helper_sys_imageblit(info, image); +} + static const struct fb_ops drm_fbdev_fb_ops = { .owner = THIS_MODULE, DRM_FB_HELPER_DEFAULT_OPS, @@ -2034,11 +2226,11 @@ static const struct fb_ops drm_fbdev_fb_ops = { .fb_release = drm_fbdev_fb_release, .fb_destroy = drm_fbdev_fb_destroy, .fb_mmap = drm_fbdev_fb_mmap, - .fb_read = drm_fb_helper_sys_read, - .fb_write = drm_fb_helper_sys_write, - .fb_fillrect = drm_fb_helper_sys_fillrect, - .fb_copyarea = drm_fb_helper_sys_copyarea, - .fb_imageblit = drm_fb_helper_sys_imageblit, + .fb_read = drm_fbdev_fb_read, + .fb_write = drm_fbdev_fb_write, + .fb_fillrect = drm_fbdev_fb_fillrect, + .fb_copyarea = drm_fbdev_fb_copyarea, + .fb_imageblit = drm_fbdev_fb_imageblit, }; static struct fb_deferred_io drm_fbdev_defio = { diff --git a/include/drm/drm_mode_config.h b/include/drm/drm_mode_config.h index 5ffbb4e..ab424dd 100644 --- a/include/drm/drm_mode_config.h +++ b/include/drm/drm_mode_config.h @@ -878,18 +878,6 @@ struct drm_mode_config { bool prefer_shadow_fbdev; /** - * @fbdev_use_iomem: - * - * Set to true if framebuffer reside in iomem. - * When set to true memcpy_toio() is used when copying the framebuffer in - * drm_fb_helper.drm_fb_helper_dirty_blit_real(). - * - * FIXME: This should be replaced with a per-mapping is_iomem - * flag (like ttm does), and then used everywhere in fbdev code. - */ - bool fbdev_use_iomem; - - /** * @quirk_addfb_prefer_xbgr_30bpp: * * Special hack for legacy ADDFB to keep nouveau userspace happy. Should