On Tue, Sep 29, 2020 at 05:14:36PM +0200, Thomas Zimmermann wrote: > 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. > > 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. > > Signed-off-by: Thomas Zimmermann <tzimmermann@xxxxxxx> > --- > drivers/gpu/drm/bochs/bochs_kms.c | 1 - > drivers/gpu/drm/drm_fb_helper.c | 217 ++++++++++++++++++++++++++++-- > include/drm/drm_mode_config.h | 12 -- > include/linux/dma-buf-map.h | 72 ++++++++-- > 4 files changed, 265 insertions(+), 37 deletions(-) > > diff --git a/drivers/gpu/drm/bochs/bochs_kms.c b/drivers/gpu/drm/bochs/bochs_kms.c > index 13d0d04c4457..853081d186d5 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 343a292f2c7c..f345a314a437 100644 > --- a/drivers/gpu/drm/drm_fb_helper.c > +++ b/drivers/gpu/drm/drm_fb_helper.c > @@ -388,24 +388,22 @@ 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]; > } > } > > @@ -433,8 +431,9 @@ 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); > @@ -771,6 +770,136 @@ void drm_fb_helper_sys_imageblit(struct fb_info *info, > } > EXPORT_SYMBOL(drm_fb_helper_sys_imageblit); > > +static ssize_t drm_fb_helper_cfb_read(struct fb_info *info, char __user *buf, > + size_t count, loff_t *ppos) > +{ > + unsigned long p = *ppos; > + u8 *dst; > + u8 __iomem *src; > + int c, err = 0; > + unsigned long total_size; > + unsigned long alloc_size; > + ssize_t ret = 0; > + > + if (info->state != FBINFO_STATE_RUNNING) > + return -EPERM; > + > + total_size = info->screen_size; > + > + if (total_size == 0) > + total_size = info->fix.smem_len; > + > + if (p >= total_size) > + return 0; > + > + if (count >= total_size) > + count = total_size; > + > + if (count + p > total_size) > + count = total_size - p; > + > + src = (u8 __iomem *)(info->screen_base + p); > + > + alloc_size = min(count, PAGE_SIZE); > + > + dst = kmalloc(alloc_size, GFP_KERNEL); > + if (!dst) > + return -ENOMEM; > + > + while (count) { > + c = min(count, alloc_size); > + > + memcpy_fromio(dst, src, c); > + if (copy_to_user(buf, dst, c)) { > + err = -EFAULT; > + break; > + } > + > + src += c; > + *ppos += c; > + buf += c; > + ret += c; > + count -= c; > + } > + > + kfree(dst); > + > + if (err) > + return err; > + > + return ret; > +} > + > +static ssize_t drm_fb_helper_cfb_write(struct fb_info *info, const char __user *buf, > + size_t count, loff_t *ppos) > +{ > + unsigned long p = *ppos; > + u8 *src; > + u8 __iomem *dst; > + int c, err = 0; > + unsigned long total_size; > + unsigned long alloc_size; > + ssize_t ret = 0; > + > + if (info->state != FBINFO_STATE_RUNNING) > + return -EPERM; > + > + total_size = info->screen_size; > + > + if (total_size == 0) > + total_size = info->fix.smem_len; > + > + if (p > total_size) > + return -EFBIG; > + > + if (count > total_size) { > + err = -EFBIG; > + count = total_size; > + } > + > + if (count + p > total_size) { > + /* > + * The framebuffer is too small. We do the > + * copy operation, but return an error code > + * afterwards. Taken from fbdev. > + */ > + if (!err) > + err = -ENOSPC; > + count = total_size - p; > + } > + > + alloc_size = min(count, PAGE_SIZE); > + > + src = kmalloc(alloc_size, GFP_KERNEL); > + if (!src) > + return -ENOMEM; > + > + dst = (u8 __iomem *)(info->screen_base + p); > + > + while (count) { > + c = min(count, alloc_size); > + > + if (copy_from_user(src, buf, c)) { > + err = -EFAULT; > + break; > + } > + memcpy_toio(dst, src, c); > + > + dst += c; > + *ppos += c; > + buf += c; > + ret += c; > + count -= c; > + } > + > + kfree(src); > + > + if (err) > + return err; > + > + return ret; > +} > + > /** > * drm_fb_helper_cfb_fillrect - wrapper around cfb_fillrect > * @info: fbdev registered by the helper > @@ -2043,6 +2172,66 @@ static int drm_fbdev_fb_mmap(struct fb_info *info, struct vm_area_struct *vma) > return -ENODEV; > } > > +static ssize_t drm_fbdev_fb_read(struct fb_info *info, char __user *buf, > + size_t count, loff_t *ppos) > +{ > + struct drm_fb_helper *fb_helper = info->par; > + struct drm_client_buffer *buffer = fb_helper->buffer; > + > + if (drm_fbdev_use_shadow_fb(fb_helper) || !buffer->map.is_iomem) > + return drm_fb_helper_sys_read(info, buf, count, ppos); > + else > + return drm_fb_helper_cfb_read(info, buf, count, ppos); > +} > + > +static ssize_t drm_fbdev_fb_write(struct fb_info *info, const char __user *buf, > + size_t count, loff_t *ppos) > +{ > + struct drm_fb_helper *fb_helper = info->par; > + struct drm_client_buffer *buffer = fb_helper->buffer; > + > + if (drm_fbdev_use_shadow_fb(fb_helper) || !buffer->map.is_iomem) > + return drm_fb_helper_sys_write(info, buf, count, ppos); > + else > + return drm_fb_helper_cfb_write(info, buf, count, ppos); > +} > + > +static void drm_fbdev_fb_fillrect(struct fb_info *info, > + const struct fb_fillrect *rect) > +{ > + struct drm_fb_helper *fb_helper = info->par; > + struct drm_client_buffer *buffer = fb_helper->buffer; > + > + if (drm_fbdev_use_shadow_fb(fb_helper) || !buffer->map.is_iomem) > + drm_fb_helper_sys_fillrect(info, rect); > + else > + drm_fb_helper_cfb_fillrect(info, rect); > +} > + > +static void drm_fbdev_fb_copyarea(struct fb_info *info, > + const struct fb_copyarea *area) > +{ > + struct drm_fb_helper *fb_helper = info->par; > + struct drm_client_buffer *buffer = fb_helper->buffer; > + > + if (drm_fbdev_use_shadow_fb(fb_helper) || !buffer->map.is_iomem) > + drm_fb_helper_sys_copyarea(info, area); > + else > + drm_fb_helper_cfb_copyarea(info, area); > +} > + > +static void drm_fbdev_fb_imageblit(struct fb_info *info, > + const struct fb_image *image) > +{ > + struct drm_fb_helper *fb_helper = info->par; > + struct drm_client_buffer *buffer = fb_helper->buffer; > + > + if (drm_fbdev_use_shadow_fb(fb_helper) || !buffer->map.is_iomem) > + drm_fb_helper_sys_imageblit(info, image); > + else > + drm_fb_helper_cfb_imageblit(info, image); > +} I think a todo to make the new generic functions the real ones, and drivers not using the sys/cfb ones anymore would be a good addition. > + > static const struct fb_ops drm_fbdev_fb_ops = { > .owner = THIS_MODULE, > DRM_FB_HELPER_DEFAULT_OPS, > @@ -2050,11 +2239,11 @@ 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 5ffbb4ed5b35..ab424ddd7665 100644 > --- a/include/drm/drm_mode_config.h > +++ b/include/drm/drm_mode_config.h > @@ -877,18 +877,6 @@ 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: > * > diff --git a/include/linux/dma-buf-map.h b/include/linux/dma-buf-map.h I think the below should be split out as a prep patch. > index 2e8bbecb5091..6ca0f304dda2 100644 > --- a/include/linux/dma-buf-map.h > +++ b/include/linux/dma-buf-map.h > @@ -32,6 +32,14 @@ > * accessing the buffer. Use the returned instance and the helper functions > * to access the buffer's memory in the correct way. > * > + * The type :c:type:`struct dma_buf_map <dma_buf_map>` and its helpers are > + * actually independent from the dma-buf infrastructure. When sharing buffers > + * among devices, drivers have to know the location of the memory to access > + * the buffers in a safe way. :c:type:`struct dma_buf_map <dma_buf_map>` > + * solves this problem for dma-buf and its users. If other drivers or > + * sub-systems require similar functionality, the type could be generalized > + * and moved to a more prominent header file. > + * > * Open-coding access to :c:type:`struct dma_buf_map <dma_buf_map>` is > * considered bad style. Rather then accessing its fields directly, use one > * of the provided helper functions, or implement your own. For example, > @@ -51,6 +59,14 @@ > * > * dma_buf_map_set_vaddr_iomem(&map. 0xdeadbeaf); > * > + * Instances of struct dma_buf_map do not have to be cleaned up, but > + * can be cleared to NULL with dma_buf_map_clear(). Cleared mappings > + * always refer to system memory. > + * > + * .. code-block:: c > + * > + * dma_buf_map_clear(&map); > + * > * Test if a mapping is valid with either dma_buf_map_is_set() or > * dma_buf_map_is_null(). > * > @@ -73,17 +89,19 @@ > * if (dma_buf_map_is_equal(&sys_map, &io_map)) > * // always false > * > - * Instances of struct dma_buf_map do not have to be cleaned up, but > - * can be cleared to NULL with dma_buf_map_clear(). Cleared mappings > - * always refer to system memory. > + * A set up instance of struct dma_buf_map can be used to access or manipulate > + * the buffer memory. Depending on the location of the memory, the provided > + * helpers will pick the correct operations. Data can be copied into the memory > + * with dma_buf_map_memcpy_to(). The address can be manipulated with > + * dma_buf_map_incr(). > * > - * The type :c:type:`struct dma_buf_map <dma_buf_map>` and its helpers are > - * actually independent from the dma-buf infrastructure. When sharing buffers > - * among devices, drivers have to know the location of the memory to access > - * the buffers in a safe way. :c:type:`struct dma_buf_map <dma_buf_map>` > - * solves this problem for dma-buf and its users. If other drivers or > - * sub-systems require similar functionality, the type could be generalized > - * and moved to a more prominent header file. > + * .. code-block:: c > + * > + * const void *src = ...; // source buffer > + * size_t len = ...; // length of src > + * > + * dma_buf_map_memcpy_to(&map, src, len); > + * dma_buf_map_incr(&map, len); // go to first byte after the memcpy > */ > > /** > @@ -210,4 +228,38 @@ static inline void dma_buf_map_clear(struct dma_buf_map *map) > } > } > > +/** > + * dma_buf_map_memcpy_to - Memcpy into dma-buf mapping > + * @dst: The dma-buf mapping structure > + * @src: The source buffer > + * @len: The number of byte in src > + * > + * Copies data into a dma-buf mapping. The source buffer is in system > + * memory. Depending on the buffer's location, the helper picks the correct > + * method of accessing the memory. > + */ > +static inline void dma_buf_map_memcpy_to(struct dma_buf_map *dst, const void *src, size_t len) > +{ > + if (dst->is_iomem) > + memcpy_toio(dst->vaddr_iomem, src, len); > + else > + memcpy(dst->vaddr, src, len); > +} > + > +/** > + * dma_buf_map_incr - Increments the address stored in a dma-buf mapping > + * @map: The dma-buf mapping structure > + * @incr: The number of bytes to increment > + * > + * Increments the address stored in a dma-buf mapping. Depending on the > + * buffer's location, the correct value will be updated. > + */ > +static inline void dma_buf_map_incr(struct dma_buf_map *map, size_t incr) > +{ > + if (map->is_iomem) > + map->vaddr_iomem += incr; > + else > + map->vaddr += incr; > +} > + > #endif /* __DMA_BUF_MAP_H__ */ > -- > 2.28.0 > -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch