1 // SPDX-License-Identifier: MIT
2
3 #include <linux/fb.h>
4
5 #include <drm/drm_crtc_helper.h>
6 #include <drm/drm_drv.h>
7 #include <drm/drm_fb_helper.h>
8 #include <drm/drm_framebuffer.h>
9 #include <drm/drm_gem_framebuffer_helper.h>
10 #include <drm/drm_gem_shmem_helper.h>
11
12 #include <drm/drm_fbdev_shmem.h>
13
14 /*
15 * struct fb_ops
16 */
17
drm_fbdev_shmem_fb_open(struct fb_info * info,int user)18 static int drm_fbdev_shmem_fb_open(struct fb_info *info, int user)
19 {
20 struct drm_fb_helper *fb_helper = info->par;
21
22 /* No need to take a ref for fbcon because it unbinds on unregister */
23 if (user && !try_module_get(fb_helper->dev->driver->fops->owner))
24 return -ENODEV;
25
26 return 0;
27 }
28
drm_fbdev_shmem_fb_release(struct fb_info * info,int user)29 static int drm_fbdev_shmem_fb_release(struct fb_info *info, int user)
30 {
31 struct drm_fb_helper *fb_helper = info->par;
32
33 if (user)
34 module_put(fb_helper->dev->driver->fops->owner);
35
36 return 0;
37 }
38
39 FB_GEN_DEFAULT_DEFERRED_SYSMEM_OPS(drm_fbdev_shmem,
40 drm_fb_helper_damage_range,
41 drm_fb_helper_damage_area);
42
drm_fbdev_shmem_fb_mmap(struct fb_info * info,struct vm_area_struct * vma)43 static int drm_fbdev_shmem_fb_mmap(struct fb_info *info, struct vm_area_struct *vma)
44 {
45 struct drm_fb_helper *fb_helper = info->par;
46 struct drm_framebuffer *fb = fb_helper->fb;
47 struct drm_gem_object *obj = drm_gem_fb_get_obj(fb, 0);
48 struct drm_gem_shmem_object *shmem = to_drm_gem_shmem_obj(obj);
49
50 if (shmem->map_wc)
51 vma->vm_page_prot = pgprot_writecombine(vma->vm_page_prot);
52
53 return fb_deferred_io_mmap(info, vma);
54 }
55
drm_fbdev_shmem_fb_destroy(struct fb_info * info)56 static void drm_fbdev_shmem_fb_destroy(struct fb_info *info)
57 {
58 struct drm_fb_helper *fb_helper = info->par;
59
60 if (!fb_helper->dev)
61 return;
62
63 fb_deferred_io_cleanup(info);
64 drm_fb_helper_fini(fb_helper);
65
66 drm_client_buffer_vunmap(fb_helper->buffer);
67 drm_client_framebuffer_delete(fb_helper->buffer);
68 drm_client_release(&fb_helper->client);
69 drm_fb_helper_unprepare(fb_helper);
70 kfree(fb_helper);
71 }
72
73 static const struct fb_ops drm_fbdev_shmem_fb_ops = {
74 .owner = THIS_MODULE,
75 .fb_open = drm_fbdev_shmem_fb_open,
76 .fb_release = drm_fbdev_shmem_fb_release,
77 __FB_DEFAULT_DEFERRED_OPS_RDWR(drm_fbdev_shmem),
78 DRM_FB_HELPER_DEFAULT_OPS,
79 __FB_DEFAULT_DEFERRED_OPS_DRAW(drm_fbdev_shmem),
80 .fb_mmap = drm_fbdev_shmem_fb_mmap,
81 .fb_destroy = drm_fbdev_shmem_fb_destroy,
82 };
83
drm_fbdev_shmem_get_page(struct fb_info * info,unsigned long offset)84 static struct page *drm_fbdev_shmem_get_page(struct fb_info *info, unsigned long offset)
85 {
86 struct drm_fb_helper *fb_helper = info->par;
87 struct drm_framebuffer *fb = fb_helper->fb;
88 struct drm_gem_object *obj = drm_gem_fb_get_obj(fb, 0);
89 struct drm_gem_shmem_object *shmem = to_drm_gem_shmem_obj(obj);
90 unsigned int i = offset >> PAGE_SHIFT;
91 struct page *page;
92
93 if (fb_WARN_ON_ONCE(info, offset > obj->size))
94 return NULL;
95
96 page = shmem->pages[i]; // protected by active vmap
97 if (page)
98 get_page(page);
99 fb_WARN_ON_ONCE(info, !page);
100
101 return page;
102 }
103
104 /*
105 * struct drm_fb_helper
106 */
107
drm_fbdev_shmem_helper_fb_probe(struct drm_fb_helper * fb_helper,struct drm_fb_helper_surface_size * sizes)108 static int drm_fbdev_shmem_helper_fb_probe(struct drm_fb_helper *fb_helper,
109 struct drm_fb_helper_surface_size *sizes)
110 {
111 struct drm_client_dev *client = &fb_helper->client;
112 struct drm_device *dev = fb_helper->dev;
113 struct drm_client_buffer *buffer;
114 struct drm_gem_shmem_object *shmem;
115 struct drm_framebuffer *fb;
116 struct fb_info *info;
117 u32 format;
118 struct iosys_map map;
119 int ret;
120
121 drm_dbg_kms(dev, "surface width(%d), height(%d) and bpp(%d)\n",
122 sizes->surface_width, sizes->surface_height,
123 sizes->surface_bpp);
124
125 format = drm_driver_legacy_fb_format(dev, sizes->surface_bpp, sizes->surface_depth);
126 buffer = drm_client_framebuffer_create(client, sizes->surface_width,
127 sizes->surface_height, format);
128 if (IS_ERR(buffer))
129 return PTR_ERR(buffer);
130 shmem = to_drm_gem_shmem_obj(buffer->gem);
131
132 fb = buffer->fb;
133
134 ret = drm_client_buffer_vmap(buffer, &map);
135 if (ret) {
136 goto err_drm_client_buffer_delete;
137 } else if (drm_WARN_ON(dev, map.is_iomem)) {
138 ret = -ENODEV; /* I/O memory not supported; use generic emulation */
139 goto err_drm_client_buffer_delete;
140 }
141
142 fb_helper->buffer = buffer;
143 fb_helper->fb = fb;
144
145 info = drm_fb_helper_alloc_info(fb_helper);
146 if (IS_ERR(info)) {
147 ret = PTR_ERR(info);
148 goto err_drm_client_buffer_vunmap;
149 }
150
151 drm_fb_helper_fill_info(info, fb_helper, sizes);
152
153 info->fbops = &drm_fbdev_shmem_fb_ops;
154
155 /* screen */
156 info->flags |= FBINFO_VIRTFB; /* system memory */
157 if (!shmem->map_wc)
158 info->flags |= FBINFO_READS_FAST; /* signal caching */
159 info->screen_size = sizes->surface_height * fb->pitches[0];
160 info->screen_buffer = map.vaddr;
161 info->fix.smem_len = info->screen_size;
162
163 /* deferred I/O */
164 fb_helper->fbdefio.delay = HZ / 20;
165 fb_helper->fbdefio.get_page = drm_fbdev_shmem_get_page;
166 fb_helper->fbdefio.deferred_io = drm_fb_helper_deferred_io;
167
168 info->fbdefio = &fb_helper->fbdefio;
169 ret = fb_deferred_io_init(info);
170 if (ret)
171 goto err_drm_fb_helper_release_info;
172
173 return 0;
174
175 err_drm_fb_helper_release_info:
176 drm_fb_helper_release_info(fb_helper);
177 err_drm_client_buffer_vunmap:
178 fb_helper->fb = NULL;
179 fb_helper->buffer = NULL;
180 drm_client_buffer_vunmap(buffer);
181 err_drm_client_buffer_delete:
182 drm_client_framebuffer_delete(buffer);
183 return ret;
184 }
185
drm_fbdev_shmem_helper_fb_dirty(struct drm_fb_helper * helper,struct drm_clip_rect * clip)186 static int drm_fbdev_shmem_helper_fb_dirty(struct drm_fb_helper *helper,
187 struct drm_clip_rect *clip)
188 {
189 struct drm_device *dev = helper->dev;
190 int ret;
191
192 /* Call damage handlers only if necessary */
193 if (!(clip->x1 < clip->x2 && clip->y1 < clip->y2))
194 return 0;
195
196 if (helper->fb->funcs->dirty) {
197 ret = helper->fb->funcs->dirty(helper->fb, NULL, 0, 0, clip, 1);
198 if (drm_WARN_ONCE(dev, ret, "Dirty helper failed: ret=%d\n", ret))
199 return ret;
200 }
201
202 return 0;
203 }
204
205 static const struct drm_fb_helper_funcs drm_fbdev_shmem_helper_funcs = {
206 .fb_probe = drm_fbdev_shmem_helper_fb_probe,
207 .fb_dirty = drm_fbdev_shmem_helper_fb_dirty,
208 };
209
210 /*
211 * struct drm_client_funcs
212 */
213
drm_fbdev_shmem_client_unregister(struct drm_client_dev * client)214 static void drm_fbdev_shmem_client_unregister(struct drm_client_dev *client)
215 {
216 struct drm_fb_helper *fb_helper = drm_fb_helper_from_client(client);
217
218 if (fb_helper->info) {
219 drm_fb_helper_unregister_info(fb_helper);
220 } else {
221 drm_client_release(&fb_helper->client);
222 drm_fb_helper_unprepare(fb_helper);
223 kfree(fb_helper);
224 }
225 }
226
drm_fbdev_shmem_client_restore(struct drm_client_dev * client)227 static int drm_fbdev_shmem_client_restore(struct drm_client_dev *client)
228 {
229 drm_fb_helper_lastclose(client->dev);
230
231 return 0;
232 }
233
drm_fbdev_shmem_client_hotplug(struct drm_client_dev * client)234 static int drm_fbdev_shmem_client_hotplug(struct drm_client_dev *client)
235 {
236 struct drm_fb_helper *fb_helper = drm_fb_helper_from_client(client);
237 struct drm_device *dev = client->dev;
238 int ret;
239
240 if (dev->fb_helper)
241 return drm_fb_helper_hotplug_event(dev->fb_helper);
242
243 ret = drm_fb_helper_init(dev, fb_helper);
244 if (ret)
245 goto err_drm_err;
246
247 if (!drm_drv_uses_atomic_modeset(dev))
248 drm_helper_disable_unused_functions(dev);
249
250 ret = drm_fb_helper_initial_config(fb_helper);
251 if (ret)
252 goto err_drm_fb_helper_fini;
253
254 return 0;
255
256 err_drm_fb_helper_fini:
257 drm_fb_helper_fini(fb_helper);
258 err_drm_err:
259 drm_err(dev, "fbdev-shmem: Failed to setup emulation (ret=%d)\n", ret);
260 return ret;
261 }
262
263 static const struct drm_client_funcs drm_fbdev_shmem_client_funcs = {
264 .owner = THIS_MODULE,
265 .unregister = drm_fbdev_shmem_client_unregister,
266 .restore = drm_fbdev_shmem_client_restore,
267 .hotplug = drm_fbdev_shmem_client_hotplug,
268 };
269
270 /**
271 * drm_fbdev_shmem_setup() - Setup fbdev emulation for GEM SHMEM helpers
272 * @dev: DRM device
273 * @preferred_bpp: Preferred bits per pixel for the device.
274 * 32 is used if this is zero.
275 *
276 * This function sets up fbdev emulation for GEM DMA drivers that support
277 * dumb buffers with a virtual address and that can be mmap'ed.
278 * drm_fbdev_shmem_setup() shall be called after the DRM driver registered
279 * the new DRM device with drm_dev_register().
280 *
281 * Restore, hotplug events and teardown are all taken care of. Drivers that do
282 * suspend/resume need to call drm_fb_helper_set_suspend_unlocked() themselves.
283 * Simple drivers might use drm_mode_config_helper_suspend().
284 *
285 * This function is safe to call even when there are no connectors present.
286 * Setup will be retried on the next hotplug event.
287 *
288 * The fbdev is destroyed by drm_dev_unregister().
289 */
drm_fbdev_shmem_setup(struct drm_device * dev,unsigned int preferred_bpp)290 void drm_fbdev_shmem_setup(struct drm_device *dev, unsigned int preferred_bpp)
291 {
292 struct drm_fb_helper *fb_helper;
293 int ret;
294
295 drm_WARN(dev, !dev->registered, "Device has not been registered.\n");
296 drm_WARN(dev, dev->fb_helper, "fb_helper is already set!\n");
297
298 fb_helper = kzalloc(sizeof(*fb_helper), GFP_KERNEL);
299 if (!fb_helper)
300 return;
301 drm_fb_helper_prepare(dev, fb_helper, preferred_bpp, &drm_fbdev_shmem_helper_funcs);
302
303 ret = drm_client_init(dev, &fb_helper->client, "fbdev", &drm_fbdev_shmem_client_funcs);
304 if (ret) {
305 drm_err(dev, "Failed to register client: %d\n", ret);
306 goto err_drm_client_init;
307 }
308
309 drm_client_register(&fb_helper->client);
310
311 return;
312
313 err_drm_client_init:
314 drm_fb_helper_unprepare(fb_helper);
315 kfree(fb_helper);
316 }
317 EXPORT_SYMBOL(drm_fbdev_shmem_setup);
318