From e4e91dbee6b49c6887a5b82100e43900b24fe0a7 Mon Sep 17 00:00:00 2001 From: Thomas Zimmermann Date: Thu, 28 Nov 2024 11:11:25 +0100 Subject: [PATCH] fbdev-dma: Add shadow buffering for deferred I/O Signed-off-by: Thomas Zimmermann --- drivers/gpu/drm/drm_fbdev_dma.c | 213 +++++++++++++++++++++++--------- 1 file changed, 153 insertions(+), 60 deletions(-) diff --git a/drivers/gpu/drm/drm_fbdev_dma.c b/drivers/gpu/drm/drm_fbdev_dma.c index b14b581c059d..5d4c5f5d0825 100644 --- a/drivers/gpu/drm/drm_fbdev_dma.c +++ b/drivers/gpu/drm/drm_fbdev_dma.c @@ -1,6 +1,7 @@ // SPDX-License-Identifier: MIT #include +#include #include #include @@ -74,33 +75,98 @@ FB_GEN_DEFAULT_DEFERRED_DMAMEM_OPS(drm_fbdev_dma, drm_fb_helper_damage_range, drm_fb_helper_damage_area); -static int drm_fbdev_dma_deferred_fb_mmap(struct fb_info *info, struct vm_area_struct *vma) +static void drm_fbdev_dma_deferred_fb_destroy(struct fb_info *info) { struct drm_fb_helper *fb_helper = info->par; - struct drm_framebuffer *fb = fb_helper->fb; - struct drm_gem_dma_object *dma = drm_fb_dma_get_gem_obj(fb, 0); + void *shadow = info->screen_buffer; + + if (!fb_helper->dev) + return; - if (!dma->map_noncoherent) - vma->vm_page_prot = pgprot_writecombine(vma->vm_page_prot); + if (info->fbdefio) + fb_deferred_io_cleanup(info); + drm_fb_helper_fini(fb_helper); + vfree(shadow); - return fb_deferred_io_mmap(info, vma); + drm_client_buffer_vunmap(fb_helper->buffer); + drm_client_framebuffer_delete(fb_helper->buffer); + drm_client_release(&fb_helper->client); + drm_fb_helper_unprepare(fb_helper); + kfree(fb_helper); } static const struct fb_ops drm_fbdev_dma_deferred_fb_ops = { .owner = THIS_MODULE, .fb_open = drm_fbdev_dma_fb_open, .fb_release = drm_fbdev_dma_fb_release, - __FB_DEFAULT_DEFERRED_OPS_RDWR(drm_fbdev_dma), + FB_DEFAULT_DEFERRED_OPS(drm_fbdev_dma), DRM_FB_HELPER_DEFAULT_OPS, - __FB_DEFAULT_DEFERRED_OPS_DRAW(drm_fbdev_dma), - .fb_mmap = drm_fbdev_dma_deferred_fb_mmap, - .fb_destroy = drm_fbdev_dma_fb_destroy, + .fb_destroy = drm_fbdev_dma_deferred_fb_destroy, }; /* * struct drm_fb_helper */ +static void drm_fbdev_dma_damage_blit_real(struct drm_fb_helper *fb_helper, + struct drm_clip_rect *clip, + struct iosys_map *dst) +{ + struct drm_framebuffer *fb = fb_helper->fb; + size_t offset = clip->y1 * fb->pitches[0]; + size_t len = clip->x2 - clip->x1; + unsigned int y; + void *src; + + switch (drm_format_info_bpp(fb->format, 0)) { + case 1: + offset += clip->x1 / 8; + len = DIV_ROUND_UP(len + clip->x1 % 8, 8); + break; + case 2: + offset += clip->x1 / 4; + len = DIV_ROUND_UP(len + clip->x1 % 4, 4); + break; + case 4: + offset += clip->x1 / 2; + len = DIV_ROUND_UP(len + clip->x1 % 2, 2); + break; + default: + offset += clip->x1 * fb->format->cpp[0]; + len *= fb->format->cpp[0]; + break; + } + + src = fb_helper->info->screen_buffer + offset; + iosys_map_incr(dst, offset); /* go to first pixel within clip rect */ + + for (y = clip->y1; y < clip->y2; y++) { + iosys_map_memcpy_to(dst, 0, src, len); + iosys_map_incr(dst, fb->pitches[0]); + src += fb->pitches[0]; + } +} + +static int drm_fbdev_dma_damage_blit(struct drm_fb_helper *fb_helper, + struct drm_clip_rect *clip) +{ + struct drm_client_buffer *buffer = fb_helper->buffer; + struct iosys_map dst; + + /* + * For fbdev emulation, we only have to protect against fbdev modeset + * operations. Nothing else will involve the client buffer's BO. So it + * is sufficient to acquire struct drm_fb_helper.lock here. + */ + mutex_lock(&fb_helper->lock); + + dst = buffer->map; + drm_fbdev_dma_damage_blit_real(fb_helper, clip, &dst); + + mutex_unlock(&fb_helper->lock); + + return 0; +} static int drm_fbdev_dma_helper_fb_dirty(struct drm_fb_helper *helper, struct drm_clip_rect *clip) { @@ -112,6 +178,10 @@ static int drm_fbdev_dma_helper_fb_dirty(struct drm_fb_helper *helper, return 0; if (helper->fb->funcs->dirty) { + ret = drm_fbdev_dma_damage_blit(helper, clip); + if (drm_WARN_ONCE(dev, ret, "Damage blitter failed: ret=%d\n", ret)) + return ret; + ret = helper->fb->funcs->dirty(helper->fb, NULL, 0, 0, clip, 1); if (drm_WARN_ONCE(dev, ret, "Dirty helper failed: ret=%d\n", ret)) return ret; @@ -128,14 +198,80 @@ static const struct drm_fb_helper_funcs drm_fbdev_dma_helper_funcs = { * struct drm_fb_helper */ +static int drm_fbdev_dma_driver_fbdev_probe_tail(struct drm_fb_helper *fb_helper, + struct drm_fb_helper_surface_size *sizes) +{ + struct drm_device *dev = fb_helper->dev; + struct drm_client_buffer *buffer = fb_helper->buffer; + struct drm_gem_dma_object *dma_obj = to_drm_gem_dma_obj(buffer->gem); + struct drm_framebuffer *fb = fb_helper->fb; + struct fb_info *info = fb_helper->info; + struct iosys_map map = buffer->map; + + info->fbops = &drm_fbdev_dma_fb_ops; + + /* screen */ + info->flags |= FBINFO_VIRTFB; /* system memory */ + if (dma_obj->map_noncoherent) + info->flags |= FBINFO_READS_FAST; /* signal caching */ + info->screen_size = sizes->surface_height * fb->pitches[0]; + info->screen_buffer = map.vaddr; + if (!(info->flags & FBINFO_HIDE_SMEM_START)) { + if (!drm_WARN_ON(dev, is_vmalloc_addr(info->screen_buffer))) + info->fix.smem_start = page_to_phys(virt_to_page(info->screen_buffer)); + } + info->fix.smem_len = info->screen_size; + + return 0; +} + +static int drm_fbdev_dma_driver_fbdev_probe_tail_deferred(struct drm_fb_helper *fb_helper, + struct drm_fb_helper_surface_size *sizes) +{ + struct drm_client_buffer *buffer = fb_helper->buffer; + struct fb_info *info = fb_helper->info; + size_t screen_size = buffer->gem->size; + void *screen_buffer; + int ret; + + /* + * Deferred I/O requires struct page for framebuffer memory, + * which is not guaranteed for all DMA ranges. We thus create + * a shadow buffer in system memory. + */ + screen_buffer = vzalloc(screen_size); + if (!screen_buffer) + return -ENOMEM; + + info->fbops = &drm_fbdev_dma_deferred_fb_ops; + + /* screen */ + info->flags |= FBINFO_VIRTFB; /* system memory */ + info->flags |= FBINFO_READS_FAST; /* signal caching */ + info->screen_buffer = screen_buffer; + info->fix.smem_len = screen_size; + + fb_helper->fbdefio.delay = HZ / 20; + fb_helper->fbdefio.deferred_io = drm_fb_helper_deferred_io; + + info->fbdefio = &fb_helper->fbdefio; + ret = fb_deferred_io_init(info); + if (ret) + goto err_vfree; + + return 0; + +err_vfree: + vfree(screen_buffer); + return ret; +} + int drm_fbdev_dma_driver_fbdev_probe(struct drm_fb_helper *fb_helper, struct drm_fb_helper_surface_size *sizes) { struct drm_client_dev *client = &fb_helper->client; struct drm_device *dev = fb_helper->dev; - bool use_deferred_io = false; struct drm_client_buffer *buffer; - struct drm_gem_dma_object *dma_obj; struct drm_framebuffer *fb; struct fb_info *info; u32 format; @@ -152,19 +288,9 @@ int drm_fbdev_dma_driver_fbdev_probe(struct drm_fb_helper *fb_helper, sizes->surface_height, format); if (IS_ERR(buffer)) return PTR_ERR(buffer); - dma_obj = to_drm_gem_dma_obj(buffer->gem); fb = buffer->fb; - /* - * Deferred I/O requires struct page for framebuffer memory, - * which is not guaranteed for all DMA ranges. We thus only - * install deferred I/O if we have a framebuffer that requires - * it. - */ - if (fb->funcs->dirty) - use_deferred_io = true; - ret = drm_client_buffer_vmap(buffer, &map); if (ret) { goto err_drm_client_buffer_delete; @@ -185,45 +311,12 @@ int drm_fbdev_dma_driver_fbdev_probe(struct drm_fb_helper *fb_helper, drm_fb_helper_fill_info(info, fb_helper, sizes); - if (use_deferred_io) - info->fbops = &drm_fbdev_dma_deferred_fb_ops; + if (fb->funcs->dirty) + ret = drm_fbdev_dma_driver_fbdev_probe_tail_deferred(fb_helper, sizes); else - info->fbops = &drm_fbdev_dma_fb_ops; - - /* screen */ - info->flags |= FBINFO_VIRTFB; /* system memory */ - if (dma_obj->map_noncoherent) - info->flags |= FBINFO_READS_FAST; /* signal caching */ - info->screen_size = sizes->surface_height * fb->pitches[0]; - info->screen_buffer = map.vaddr; - if (!(info->flags & FBINFO_HIDE_SMEM_START)) { - if (!drm_WARN_ON(dev, is_vmalloc_addr(info->screen_buffer))) - info->fix.smem_start = page_to_phys(virt_to_page(info->screen_buffer)); - } - info->fix.smem_len = info->screen_size; - - /* - * Only set up deferred I/O if the screen buffer supports - * it. If this disagrees with the previous test for ->dirty, - * mmap on the /dev/fb file might not work correctly. - */ - if (!is_vmalloc_addr(info->screen_buffer) && info->fix.smem_start) { - unsigned long pfn = info->fix.smem_start >> PAGE_SHIFT; - - if (drm_WARN_ON(dev, !pfn_to_page(pfn))) - use_deferred_io = false; - } - - /* deferred I/O */ - if (use_deferred_io) { - fb_helper->fbdefio.delay = HZ / 20; - fb_helper->fbdefio.deferred_io = drm_fb_helper_deferred_io; - - info->fbdefio = &fb_helper->fbdefio; - ret = fb_deferred_io_init(info); - if (ret) - goto err_drm_fb_helper_release_info; - } + ret = drm_fbdev_dma_driver_fbdev_probe_tail(fb_helper, sizes); + if (ret) + goto err_drm_fb_helper_release_info; return 0; -- 2.47.0