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_dma_helper.h>
10
11 #include <drm/drm_fbdev_dma.h>
12
13 /*
14 * struct fb_ops
15 */
16
17 #ifdef __linux__
18
drm_fbdev_dma_fb_open(struct fb_info * info,int user)19 static int drm_fbdev_dma_fb_open(struct fb_info *info, int user)
20 {
21 struct drm_fb_helper *fb_helper = info->par;
22
23 /* No need to take a ref for fbcon because it unbinds on unregister */
24 if (user && !try_module_get(fb_helper->dev->driver->fops->owner))
25 return -ENODEV;
26
27 return 0;
28 }
29
drm_fbdev_dma_fb_release(struct fb_info * info,int user)30 static int drm_fbdev_dma_fb_release(struct fb_info *info, int user)
31 {
32 struct drm_fb_helper *fb_helper = info->par;
33
34 if (user)
35 module_put(fb_helper->dev->driver->fops->owner);
36
37 return 0;
38 }
39
drm_fbdev_dma_fb_destroy(struct fb_info * info)40 static void drm_fbdev_dma_fb_destroy(struct fb_info *info)
41 {
42 struct drm_fb_helper *fb_helper = info->par;
43
44 if (!fb_helper->dev)
45 return;
46
47 drm_fb_helper_fini(fb_helper);
48
49 drm_client_buffer_vunmap(fb_helper->buffer);
50 drm_client_framebuffer_delete(fb_helper->buffer);
51 drm_client_release(&fb_helper->client);
52 drm_fb_helper_unprepare(fb_helper);
53 kfree(fb_helper);
54 }
55
drm_fbdev_dma_fb_mmap(struct fb_info * info,struct vm_area_struct * vma)56 static int drm_fbdev_dma_fb_mmap(struct fb_info *info, struct vm_area_struct *vma)
57 {
58 struct drm_fb_helper *fb_helper = info->par;
59
60 return drm_gem_prime_mmap(fb_helper->buffer->gem, vma);
61 }
62
63 #endif /* __linux__ */
64
65 static const struct fb_ops drm_fbdev_dma_fb_ops = {
66 #ifdef notyet
67 .owner = THIS_MODULE,
68 .fb_open = drm_fbdev_dma_fb_open,
69 .fb_release = drm_fbdev_dma_fb_release,
70 __FB_DEFAULT_DMAMEM_OPS_RDWR,
71 DRM_FB_HELPER_DEFAULT_OPS,
72 __FB_DEFAULT_DMAMEM_OPS_DRAW,
73 .fb_mmap = drm_fbdev_dma_fb_mmap,
74 .fb_destroy = drm_fbdev_dma_fb_destroy,
75 #else
76 DRM_FB_HELPER_DEFAULT_OPS,
77 #endif
78 };
79
80 /*
81 * struct drm_fb_helper
82 */
83
drm_fbdev_dma_helper_fb_probe(struct drm_fb_helper * fb_helper,struct drm_fb_helper_surface_size * sizes)84 static int drm_fbdev_dma_helper_fb_probe(struct drm_fb_helper *fb_helper,
85 struct drm_fb_helper_surface_size *sizes)
86 {
87 struct drm_client_dev *client = &fb_helper->client;
88 struct drm_device *dev = fb_helper->dev;
89 struct drm_client_buffer *buffer;
90 struct drm_gem_dma_object *dma_obj;
91 struct drm_framebuffer *fb;
92 struct fb_info *info;
93 u32 format;
94 struct iosys_map map;
95 int ret;
96
97 drm_dbg_kms(dev, "surface width(%d), height(%d) and bpp(%d)\n",
98 sizes->surface_width, sizes->surface_height,
99 sizes->surface_bpp);
100
101 format = drm_mode_legacy_fb_format(sizes->surface_bpp, sizes->surface_depth);
102 buffer = drm_client_framebuffer_create(client, sizes->surface_width,
103 sizes->surface_height, format);
104 if (IS_ERR(buffer))
105 return PTR_ERR(buffer);
106 dma_obj = to_drm_gem_dma_obj(buffer->gem);
107
108 fb = buffer->fb;
109 if (drm_WARN_ON(dev, fb->funcs->dirty)) {
110 ret = -ENODEV; /* damage handling not supported; use generic emulation */
111 goto err_drm_client_buffer_delete;
112 }
113
114 ret = drm_client_buffer_vmap(buffer, &map);
115 if (ret) {
116 goto err_drm_client_buffer_delete;
117 } else if (drm_WARN_ON(dev, map.is_iomem)) {
118 ret = -ENODEV; /* I/O memory not supported; use generic emulation */
119 goto err_drm_client_buffer_delete;
120 }
121
122 fb_helper->buffer = buffer;
123 fb_helper->fb = buffer->fb;
124
125 info = drm_fb_helper_alloc_info(fb_helper);
126 if (IS_ERR(info)) {
127 ret = PTR_ERR(info);
128 goto err_drm_client_buffer_vunmap;
129 }
130
131 drm_fb_helper_fill_info(info, fb_helper, sizes);
132
133 info->fbops = &drm_fbdev_dma_fb_ops;
134
135 /* screen */
136 info->flags |= FBINFO_VIRTFB; /* system memory */
137 if (dma_obj->map_noncoherent)
138 info->flags |= FBINFO_READS_FAST; /* signal caching */
139 info->screen_size = sizes->surface_height * fb->pitches[0];
140 info->screen_buffer = map.vaddr;
141 if (!(info->flags & FBINFO_HIDE_SMEM_START)) {
142 if (!drm_WARN_ON(dev, is_vmalloc_addr(info->screen_buffer)))
143 info->fix.smem_start = page_to_phys(virt_to_page(info->screen_buffer));
144 }
145 info->fix.smem_len = info->screen_size;
146
147 return 0;
148
149 err_drm_client_buffer_vunmap:
150 fb_helper->fb = NULL;
151 fb_helper->buffer = NULL;
152 drm_client_buffer_vunmap(buffer);
153 err_drm_client_buffer_delete:
154 drm_client_framebuffer_delete(buffer);
155 return ret;
156 }
157
158 static const struct drm_fb_helper_funcs drm_fbdev_dma_helper_funcs = {
159 .fb_probe = drm_fbdev_dma_helper_fb_probe,
160 };
161
162 /*
163 * struct drm_client_funcs
164 */
165
drm_fbdev_dma_client_unregister(struct drm_client_dev * client)166 static void drm_fbdev_dma_client_unregister(struct drm_client_dev *client)
167 {
168 struct drm_fb_helper *fb_helper = drm_fb_helper_from_client(client);
169
170 if (fb_helper->info) {
171 drm_fb_helper_unregister_info(fb_helper);
172 } else {
173 drm_client_release(&fb_helper->client);
174 drm_fb_helper_unprepare(fb_helper);
175 kfree(fb_helper);
176 }
177 }
178
drm_fbdev_dma_client_restore(struct drm_client_dev * client)179 static int drm_fbdev_dma_client_restore(struct drm_client_dev *client)
180 {
181 drm_fb_helper_lastclose(client->dev);
182
183 return 0;
184 }
185
drm_fbdev_dma_client_hotplug(struct drm_client_dev * client)186 static int drm_fbdev_dma_client_hotplug(struct drm_client_dev *client)
187 {
188 struct drm_fb_helper *fb_helper = drm_fb_helper_from_client(client);
189 struct drm_device *dev = client->dev;
190 int ret;
191
192 if (dev->fb_helper)
193 return drm_fb_helper_hotplug_event(dev->fb_helper);
194
195 ret = drm_fb_helper_init(dev, fb_helper);
196 if (ret)
197 goto err_drm_err;
198
199 if (!drm_drv_uses_atomic_modeset(dev))
200 drm_helper_disable_unused_functions(dev);
201
202 ret = drm_fb_helper_initial_config(fb_helper);
203 if (ret)
204 goto err_drm_fb_helper_fini;
205
206 return 0;
207
208 err_drm_fb_helper_fini:
209 drm_fb_helper_fini(fb_helper);
210 err_drm_err:
211 drm_err(dev, "fbdev-dma: Failed to setup generic emulation (ret=%d)\n", ret);
212 return ret;
213 }
214
215 static const struct drm_client_funcs drm_fbdev_dma_client_funcs = {
216 .owner = THIS_MODULE,
217 .unregister = drm_fbdev_dma_client_unregister,
218 .restore = drm_fbdev_dma_client_restore,
219 .hotplug = drm_fbdev_dma_client_hotplug,
220 };
221
222 /**
223 * drm_fbdev_dma_setup() - Setup fbdev emulation for GEM DMA helpers
224 * @dev: DRM device
225 * @preferred_bpp: Preferred bits per pixel for the device.
226 * 32 is used if this is zero.
227 *
228 * This function sets up fbdev emulation for GEM DMA drivers that support
229 * dumb buffers with a virtual address and that can be mmap'ed.
230 * drm_fbdev_dma_setup() shall be called after the DRM driver registered
231 * the new DRM device with drm_dev_register().
232 *
233 * Restore, hotplug events and teardown are all taken care of. Drivers that do
234 * suspend/resume need to call drm_fb_helper_set_suspend_unlocked() themselves.
235 * Simple drivers might use drm_mode_config_helper_suspend().
236 *
237 * This function is safe to call even when there are no connectors present.
238 * Setup will be retried on the next hotplug event.
239 *
240 * The fbdev is destroyed by drm_dev_unregister().
241 */
drm_fbdev_dma_setup(struct drm_device * dev,unsigned int preferred_bpp)242 void drm_fbdev_dma_setup(struct drm_device *dev, unsigned int preferred_bpp)
243 {
244 struct drm_fb_helper *fb_helper;
245 int ret;
246
247 drm_WARN(dev, !dev->registered, "Device has not been registered.\n");
248 drm_WARN(dev, dev->fb_helper, "fb_helper is already set!\n");
249
250 fb_helper = kzalloc(sizeof(*fb_helper), GFP_KERNEL);
251 if (!fb_helper)
252 return;
253 drm_fb_helper_prepare(dev, fb_helper, preferred_bpp, &drm_fbdev_dma_helper_funcs);
254
255 ret = drm_client_init(dev, &fb_helper->client, "fbdev", &drm_fbdev_dma_client_funcs);
256 if (ret) {
257 drm_err(dev, "Failed to register client: %d\n", ret);
258 goto err_drm_client_init;
259 }
260
261 drm_client_register(&fb_helper->client);
262
263 return;
264
265 err_drm_client_init:
266 drm_fb_helper_unprepare(fb_helper);
267 kfree(fb_helper);
268 }
269 EXPORT_SYMBOL(drm_fbdev_dma_setup);
270