1 // SPDX-License-Identifier: MIT
3 #include <linux/moduleparam.h>
4 #include <linux/vmalloc.h>
6 #include <drm/drm_crtc_helper.h>
7 #include <drm/drm_drv.h>
8 #include <drm/drm_fb_helper.h>
9 #include <drm/drm_framebuffer.h>
10 #include <drm/drm_gem.h>
11 #include <drm/drm_print.h>
13 #include <drm/drm_fbdev_generic.h>
15 /* @user: 1=userspace, 0=fbcon */
16 static int drm_fbdev_generic_fb_open(struct fb_info *info, int user)
18 struct drm_fb_helper *fb_helper = info->par;
20 /* No need to take a ref for fbcon because it unbinds on unregister */
21 if (user && !try_module_get(fb_helper->dev->driver->fops->owner))
27 static int drm_fbdev_generic_fb_release(struct fb_info *info, int user)
29 struct drm_fb_helper *fb_helper = info->par;
32 module_put(fb_helper->dev->driver->fops->owner);
37 FB_GEN_DEFAULT_DEFERRED_SYSMEM_OPS(drm_fbdev_generic,
38 drm_fb_helper_damage_range,
39 drm_fb_helper_damage_area);
41 static void drm_fbdev_generic_fb_destroy(struct fb_info *info)
43 struct drm_fb_helper *fb_helper = info->par;
44 void *shadow = info->screen_buffer;
49 fb_deferred_io_cleanup(info);
50 drm_fb_helper_fini(fb_helper);
52 drm_client_framebuffer_delete(fb_helper->buffer);
54 drm_client_release(&fb_helper->client);
55 drm_fb_helper_unprepare(fb_helper);
59 static const struct fb_ops drm_fbdev_generic_fb_ops = {
61 .fb_open = drm_fbdev_generic_fb_open,
62 .fb_release = drm_fbdev_generic_fb_release,
63 FB_DEFAULT_DEFERRED_OPS(drm_fbdev_generic),
64 DRM_FB_HELPER_DEFAULT_OPS,
65 .fb_destroy = drm_fbdev_generic_fb_destroy,
69 * This function uses the client API to create a framebuffer backed by a dumb buffer.
71 static int drm_fbdev_generic_helper_fb_probe(struct drm_fb_helper *fb_helper,
72 struct drm_fb_helper_surface_size *sizes)
74 struct drm_client_dev *client = &fb_helper->client;
75 struct drm_device *dev = fb_helper->dev;
76 struct drm_client_buffer *buffer;
83 drm_dbg_kms(dev, "surface width(%d), height(%d) and bpp(%d)\n",
84 sizes->surface_width, sizes->surface_height,
87 format = drm_mode_legacy_fb_format(sizes->surface_bpp, sizes->surface_depth);
88 buffer = drm_client_framebuffer_create(client, sizes->surface_width,
89 sizes->surface_height, format);
91 return PTR_ERR(buffer);
93 fb_helper->buffer = buffer;
94 fb_helper->fb = buffer->fb;
96 screen_size = buffer->gem->size;
97 screen_buffer = vzalloc(screen_size);
100 goto err_drm_client_framebuffer_delete;
103 info = drm_fb_helper_alloc_info(fb_helper);
109 drm_fb_helper_fill_info(info, fb_helper, sizes);
111 info->fbops = &drm_fbdev_generic_fb_ops;
114 info->flags |= FBINFO_VIRTFB | FBINFO_READS_FAST;
115 info->screen_buffer = screen_buffer;
116 info->fix.smem_len = screen_size;
119 fb_helper->fbdefio.delay = HZ / 20;
120 fb_helper->fbdefio.deferred_io = drm_fb_helper_deferred_io;
122 info->fbdefio = &fb_helper->fbdefio;
123 ret = fb_deferred_io_init(info);
125 goto err_drm_fb_helper_release_info;
129 err_drm_fb_helper_release_info:
130 drm_fb_helper_release_info(fb_helper);
132 vfree(screen_buffer);
133 err_drm_client_framebuffer_delete:
134 fb_helper->fb = NULL;
135 fb_helper->buffer = NULL;
136 drm_client_framebuffer_delete(buffer);
140 static void drm_fbdev_generic_damage_blit_real(struct drm_fb_helper *fb_helper,
141 struct drm_clip_rect *clip,
142 struct iosys_map *dst)
144 struct drm_framebuffer *fb = fb_helper->fb;
145 size_t offset = clip->y1 * fb->pitches[0];
146 size_t len = clip->x2 - clip->x1;
150 switch (drm_format_info_bpp(fb->format, 0)) {
152 offset += clip->x1 / 8;
153 len = DIV_ROUND_UP(len + clip->x1 % 8, 8);
156 offset += clip->x1 / 4;
157 len = DIV_ROUND_UP(len + clip->x1 % 4, 4);
160 offset += clip->x1 / 2;
161 len = DIV_ROUND_UP(len + clip->x1 % 2, 2);
164 offset += clip->x1 * fb->format->cpp[0];
165 len *= fb->format->cpp[0];
169 src = fb_helper->info->screen_buffer + offset;
170 iosys_map_incr(dst, offset); /* go to first pixel within clip rect */
172 for (y = clip->y1; y < clip->y2; y++) {
173 iosys_map_memcpy_to(dst, 0, src, len);
174 iosys_map_incr(dst, fb->pitches[0]);
175 src += fb->pitches[0];
179 static int drm_fbdev_generic_damage_blit(struct drm_fb_helper *fb_helper,
180 struct drm_clip_rect *clip)
182 struct drm_client_buffer *buffer = fb_helper->buffer;
183 struct iosys_map map, dst;
187 * We have to pin the client buffer to its current location while
188 * flushing the shadow buffer. In the general case, concurrent
189 * modesetting operations could try to move the buffer and would
190 * fail. The modeset has to be serialized by acquiring the reservation
191 * object of the underlying BO here.
193 * For fbdev emulation, we only have to protect against fbdev modeset
194 * operations. Nothing else will involve the client buffer's BO. So it
195 * is sufficient to acquire struct drm_fb_helper.lock here.
197 mutex_lock(&fb_helper->lock);
199 ret = drm_client_buffer_vmap_local(buffer, &map);
204 drm_fbdev_generic_damage_blit_real(fb_helper, clip, &dst);
206 drm_client_buffer_vunmap_local(buffer);
209 mutex_unlock(&fb_helper->lock);
214 static int drm_fbdev_generic_helper_fb_dirty(struct drm_fb_helper *helper,
215 struct drm_clip_rect *clip)
217 struct drm_device *dev = helper->dev;
220 /* Call damage handlers only if necessary */
221 if (!(clip->x1 < clip->x2 && clip->y1 < clip->y2))
224 ret = drm_fbdev_generic_damage_blit(helper, clip);
225 if (drm_WARN_ONCE(dev, ret, "Damage blitter failed: ret=%d\n", ret))
228 if (helper->fb->funcs->dirty) {
229 ret = helper->fb->funcs->dirty(helper->fb, NULL, 0, 0, clip, 1);
230 if (drm_WARN_ONCE(dev, ret, "Dirty helper failed: ret=%d\n", ret))
237 static const struct drm_fb_helper_funcs drm_fbdev_generic_helper_funcs = {
238 .fb_probe = drm_fbdev_generic_helper_fb_probe,
239 .fb_dirty = drm_fbdev_generic_helper_fb_dirty,
242 static void drm_fbdev_generic_client_unregister(struct drm_client_dev *client)
244 struct drm_fb_helper *fb_helper = drm_fb_helper_from_client(client);
246 if (fb_helper->info) {
247 drm_fb_helper_unregister_info(fb_helper);
249 drm_client_release(&fb_helper->client);
250 drm_fb_helper_unprepare(fb_helper);
255 static int drm_fbdev_generic_client_restore(struct drm_client_dev *client)
257 drm_fb_helper_lastclose(client->dev);
262 static int drm_fbdev_generic_client_hotplug(struct drm_client_dev *client)
264 struct drm_fb_helper *fb_helper = drm_fb_helper_from_client(client);
265 struct drm_device *dev = client->dev;
269 return drm_fb_helper_hotplug_event(dev->fb_helper);
271 ret = drm_fb_helper_init(dev, fb_helper);
275 if (!drm_drv_uses_atomic_modeset(dev))
276 drm_helper_disable_unused_functions(dev);
278 ret = drm_fb_helper_initial_config(fb_helper);
280 goto err_drm_fb_helper_fini;
284 err_drm_fb_helper_fini:
285 drm_fb_helper_fini(fb_helper);
287 drm_err(dev, "fbdev: Failed to setup generic emulation (ret=%d)\n", ret);
291 static const struct drm_client_funcs drm_fbdev_generic_client_funcs = {
292 .owner = THIS_MODULE,
293 .unregister = drm_fbdev_generic_client_unregister,
294 .restore = drm_fbdev_generic_client_restore,
295 .hotplug = drm_fbdev_generic_client_hotplug,
299 * drm_fbdev_generic_setup() - Setup generic fbdev emulation
301 * @preferred_bpp: Preferred bits per pixel for the device.
303 * This function sets up generic fbdev emulation for drivers that supports
304 * dumb buffers with a virtual address and that can be mmap'ed.
305 * drm_fbdev_generic_setup() shall be called after the DRM driver registered
306 * the new DRM device with drm_dev_register().
308 * Restore, hotplug events and teardown are all taken care of. Drivers that do
309 * suspend/resume need to call drm_fb_helper_set_suspend_unlocked() themselves.
310 * Simple drivers might use drm_mode_config_helper_suspend().
312 * In order to provide fixed mmap-able memory ranges, generic fbdev emulation
313 * uses a shadow buffer in system memory. The implementation blits the shadow
314 * fbdev buffer onto the real buffer in regular intervals.
316 * This function is safe to call even when there are no connectors present.
317 * Setup will be retried on the next hotplug event.
319 * The fbdev is destroyed by drm_dev_unregister().
321 void drm_fbdev_generic_setup(struct drm_device *dev, unsigned int preferred_bpp)
323 struct drm_fb_helper *fb_helper;
326 drm_WARN(dev, !dev->registered, "Device has not been registered.\n");
327 drm_WARN(dev, dev->fb_helper, "fb_helper is already set!\n");
329 fb_helper = kzalloc(sizeof(*fb_helper), GFP_KERNEL);
332 drm_fb_helper_prepare(dev, fb_helper, preferred_bpp, &drm_fbdev_generic_helper_funcs);
334 ret = drm_client_init(dev, &fb_helper->client, "fbdev", &drm_fbdev_generic_client_funcs);
336 drm_err(dev, "Failed to register client: %d\n", ret);
337 goto err_drm_client_init;
340 drm_client_register(&fb_helper->client);
345 drm_fb_helper_unprepare(fb_helper);
349 EXPORT_SYMBOL(drm_fbdev_generic_setup);