1 // SPDX-License-Identifier: GPL-2.0+
2
3 /**
4 * DOC: vkms (Virtual Kernel Modesetting)
5 *
6 * VKMS is a software-only model of a KMS driver that is useful for testing
7 * and for running X (or similar) on headless machines. VKMS aims to enable
8 * a virtual display with no need of a hardware display capability, releasing
9 * the GPU in DRM API tests.
10 */
11
12 #include <linux/module.h>
13 #include <linux/platform_device.h>
14 #include <linux/dma-mapping.h>
15
16 #include <drm/clients/drm_client_setup.h>
17 #include <drm/drm_gem.h>
18 #include <drm/drm_atomic.h>
19 #include <drm/drm_atomic_helper.h>
20 #include <drm/drm_drv.h>
21 #include <drm/drm_fbdev_shmem.h>
22 #include <drm/drm_file.h>
23 #include <drm/drm_gem_framebuffer_helper.h>
24 #include <drm/drm_ioctl.h>
25 #include <drm/drm_managed.h>
26 #include <drm/drm_probe_helper.h>
27 #include <drm/drm_gem_shmem_helper.h>
28 #include <drm/drm_vblank.h>
29
30 #include "vkms_drv.h"
31
32 #include <drm/drm_print.h>
33 #include <drm/drm_debugfs.h>
34
35 #define DRIVER_NAME "vkms"
36 #define DRIVER_DESC "Virtual Kernel Mode Setting"
37 #define DRIVER_MAJOR 1
38 #define DRIVER_MINOR 0
39
40 static struct vkms_config *default_config;
41
42 static bool enable_cursor = true;
43 module_param_named(enable_cursor, enable_cursor, bool, 0444);
44 MODULE_PARM_DESC(enable_cursor, "Enable/Disable cursor support");
45
46 static bool enable_writeback = true;
47 module_param_named(enable_writeback, enable_writeback, bool, 0444);
48 MODULE_PARM_DESC(enable_writeback, "Enable/Disable writeback connector support");
49
50 static bool enable_overlay;
51 module_param_named(enable_overlay, enable_overlay, bool, 0444);
52 MODULE_PARM_DESC(enable_overlay, "Enable/Disable overlay support");
53
54 DEFINE_DRM_GEM_FOPS(vkms_driver_fops);
55
vkms_release(struct drm_device * dev)56 static void vkms_release(struct drm_device *dev)
57 {
58 struct vkms_device *vkms = drm_device_to_vkms_device(dev);
59
60 if (vkms->output.composer_workq)
61 destroy_workqueue(vkms->output.composer_workq);
62 }
63
vkms_atomic_commit_tail(struct drm_atomic_state * old_state)64 static void vkms_atomic_commit_tail(struct drm_atomic_state *old_state)
65 {
66 struct drm_device *dev = old_state->dev;
67 struct drm_crtc *crtc;
68 struct drm_crtc_state *old_crtc_state;
69 int i;
70
71 drm_atomic_helper_commit_modeset_disables(dev, old_state);
72
73 drm_atomic_helper_commit_planes(dev, old_state, 0);
74
75 drm_atomic_helper_commit_modeset_enables(dev, old_state);
76
77 drm_atomic_helper_fake_vblank(old_state);
78
79 drm_atomic_helper_commit_hw_done(old_state);
80
81 drm_atomic_helper_wait_for_flip_done(dev, old_state);
82
83 for_each_old_crtc_in_state(old_state, crtc, old_crtc_state, i) {
84 struct vkms_crtc_state *vkms_state = to_vkms_crtc_state(old_crtc_state);
85
86 flush_work(&vkms_state->composer_work);
87 }
88
89 drm_atomic_helper_cleanup_planes(dev, old_state);
90 }
91
vkms_config_show(struct seq_file * m,void * data)92 static int vkms_config_show(struct seq_file *m, void *data)
93 {
94 struct drm_debugfs_entry *entry = m->private;
95 struct drm_device *dev = entry->dev;
96 struct vkms_device *vkmsdev = drm_device_to_vkms_device(dev);
97
98 seq_printf(m, "writeback=%d\n", vkmsdev->config->writeback);
99 seq_printf(m, "cursor=%d\n", vkmsdev->config->cursor);
100 seq_printf(m, "overlay=%d\n", vkmsdev->config->overlay);
101
102 return 0;
103 }
104
105 static const struct drm_debugfs_info vkms_config_debugfs_list[] = {
106 { "vkms_config", vkms_config_show, 0 },
107 };
108
109 static const struct drm_driver vkms_driver = {
110 .driver_features = DRIVER_MODESET | DRIVER_ATOMIC | DRIVER_GEM,
111 .release = vkms_release,
112 .fops = &vkms_driver_fops,
113 DRM_GEM_SHMEM_DRIVER_OPS,
114 DRM_FBDEV_SHMEM_DRIVER_OPS,
115
116 .name = DRIVER_NAME,
117 .desc = DRIVER_DESC,
118 .major = DRIVER_MAJOR,
119 .minor = DRIVER_MINOR,
120 };
121
vkms_atomic_check(struct drm_device * dev,struct drm_atomic_state * state)122 static int vkms_atomic_check(struct drm_device *dev, struct drm_atomic_state *state)
123 {
124 struct drm_crtc *crtc;
125 struct drm_crtc_state *new_crtc_state;
126 int i;
127
128 for_each_new_crtc_in_state(state, crtc, new_crtc_state, i) {
129 if (!new_crtc_state->gamma_lut || !new_crtc_state->color_mgmt_changed)
130 continue;
131
132 if (new_crtc_state->gamma_lut->length / sizeof(struct drm_color_lut *)
133 > VKMS_LUT_SIZE)
134 return -EINVAL;
135 }
136
137 return drm_atomic_helper_check(dev, state);
138 }
139
140 static const struct drm_mode_config_funcs vkms_mode_funcs = {
141 .fb_create = drm_gem_fb_create,
142 .atomic_check = vkms_atomic_check,
143 .atomic_commit = drm_atomic_helper_commit,
144 };
145
146 static const struct drm_mode_config_helper_funcs vkms_mode_config_helpers = {
147 .atomic_commit_tail = vkms_atomic_commit_tail,
148 };
149
vkms_modeset_init(struct vkms_device * vkmsdev)150 static int vkms_modeset_init(struct vkms_device *vkmsdev)
151 {
152 struct drm_device *dev = &vkmsdev->drm;
153 int ret;
154
155 ret = drmm_mode_config_init(dev);
156 if (ret)
157 return ret;
158
159 dev->mode_config.funcs = &vkms_mode_funcs;
160 dev->mode_config.min_width = XRES_MIN;
161 dev->mode_config.min_height = YRES_MIN;
162 dev->mode_config.max_width = XRES_MAX;
163 dev->mode_config.max_height = YRES_MAX;
164 dev->mode_config.cursor_width = 512;
165 dev->mode_config.cursor_height = 512;
166 /*
167 * FIXME: There's a confusion between bpp and depth between this and
168 * fbdev helpers. We have to go with 0, meaning "pick the default",
169 * which is XRGB8888 in all cases.
170 */
171 dev->mode_config.preferred_depth = 0;
172 dev->mode_config.helper_private = &vkms_mode_config_helpers;
173
174 return vkms_output_init(vkmsdev);
175 }
176
vkms_create(struct vkms_config * config)177 static int vkms_create(struct vkms_config *config)
178 {
179 int ret;
180 struct platform_device *pdev;
181 struct vkms_device *vkms_device;
182
183 pdev = platform_device_register_simple(DRIVER_NAME, -1, NULL, 0);
184 if (IS_ERR(pdev))
185 return PTR_ERR(pdev);
186
187 if (!devres_open_group(&pdev->dev, NULL, GFP_KERNEL)) {
188 ret = -ENOMEM;
189 goto out_unregister;
190 }
191
192 vkms_device = devm_drm_dev_alloc(&pdev->dev, &vkms_driver,
193 struct vkms_device, drm);
194 if (IS_ERR(vkms_device)) {
195 ret = PTR_ERR(vkms_device);
196 goto out_devres;
197 }
198 vkms_device->platform = pdev;
199 vkms_device->config = config;
200 config->dev = vkms_device;
201
202 ret = dma_coerce_mask_and_coherent(vkms_device->drm.dev,
203 DMA_BIT_MASK(64));
204
205 if (ret) {
206 DRM_ERROR("Could not initialize DMA support\n");
207 goto out_devres;
208 }
209
210 ret = drm_vblank_init(&vkms_device->drm, 1);
211 if (ret) {
212 DRM_ERROR("Failed to vblank\n");
213 goto out_devres;
214 }
215
216 ret = vkms_modeset_init(vkms_device);
217 if (ret)
218 goto out_devres;
219
220 drm_debugfs_add_files(&vkms_device->drm, vkms_config_debugfs_list,
221 ARRAY_SIZE(vkms_config_debugfs_list));
222
223 ret = drm_dev_register(&vkms_device->drm, 0);
224 if (ret)
225 goto out_devres;
226
227 drm_client_setup(&vkms_device->drm, NULL);
228
229 return 0;
230
231 out_devres:
232 devres_release_group(&pdev->dev, NULL);
233 out_unregister:
234 platform_device_unregister(pdev);
235 return ret;
236 }
237
vkms_init(void)238 static int __init vkms_init(void)
239 {
240 int ret;
241 struct vkms_config *config;
242
243 config = kmalloc(sizeof(*config), GFP_KERNEL);
244 if (!config)
245 return -ENOMEM;
246
247 default_config = config;
248
249 config->cursor = enable_cursor;
250 config->writeback = enable_writeback;
251 config->overlay = enable_overlay;
252
253 ret = vkms_create(config);
254 if (ret)
255 kfree(config);
256
257 return ret;
258 }
259
vkms_destroy(struct vkms_config * config)260 static void vkms_destroy(struct vkms_config *config)
261 {
262 struct platform_device *pdev;
263
264 if (!config->dev) {
265 DRM_INFO("vkms_device is NULL.\n");
266 return;
267 }
268
269 pdev = config->dev->platform;
270
271 drm_dev_unregister(&config->dev->drm);
272 drm_atomic_helper_shutdown(&config->dev->drm);
273 devres_release_group(&pdev->dev, NULL);
274 platform_device_unregister(pdev);
275
276 config->dev = NULL;
277 }
278
vkms_exit(void)279 static void __exit vkms_exit(void)
280 {
281 if (default_config->dev)
282 vkms_destroy(default_config);
283
284 kfree(default_config);
285 }
286
287 module_init(vkms_init);
288 module_exit(vkms_exit);
289
290 MODULE_AUTHOR("Haneen Mohammed <hamohammed.sa@gmail.com>");
291 MODULE_AUTHOR("Rodrigo Siqueira <rodrigosiqueiramelo@gmail.com>");
292 MODULE_DESCRIPTION(DRIVER_DESC);
293 MODULE_LICENSE("GPL");
294