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/device/faux.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_print.h>
27 #include <drm/drm_probe_helper.h>
28 #include <drm/drm_gem_shmem_helper.h>
29 #include <drm/drm_vblank.h>
30
31 #include "vkms_config.h"
32 #include "vkms_configfs.h"
33 #include "vkms_drv.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 static bool enable_plane_pipeline;
55 module_param_named(enable_plane_pipeline, enable_plane_pipeline, bool, 0444);
56 MODULE_PARM_DESC(enable_plane_pipeline, "Enable/Disable plane pipeline support");
57
58 static bool create_default_dev = true;
59 module_param_named(create_default_dev, create_default_dev, bool, 0444);
60 MODULE_PARM_DESC(create_default_dev, "Create or not the default VKMS device");
61
62 DEFINE_DRM_GEM_FOPS(vkms_driver_fops);
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
92 static const struct drm_driver vkms_driver = {
93 .driver_features = DRIVER_MODESET | DRIVER_ATOMIC | DRIVER_GEM,
94 .fops = &vkms_driver_fops,
95 DRM_GEM_SHMEM_DRIVER_OPS,
96 DRM_FBDEV_SHMEM_DRIVER_OPS,
97
98 .name = DRIVER_NAME,
99 .desc = DRIVER_DESC,
100 .major = DRIVER_MAJOR,
101 .minor = DRIVER_MINOR,
102 };
103
vkms_atomic_check(struct drm_device * dev,struct drm_atomic_state * state)104 static int vkms_atomic_check(struct drm_device *dev, struct drm_atomic_state *state)
105 {
106 struct drm_crtc *crtc;
107 struct drm_crtc_state *new_crtc_state;
108 int i;
109
110 for_each_new_crtc_in_state(state, crtc, new_crtc_state, i) {
111 if (!new_crtc_state->gamma_lut || !new_crtc_state->color_mgmt_changed)
112 continue;
113
114 if (new_crtc_state->gamma_lut->length / sizeof(struct drm_color_lut *)
115 > VKMS_LUT_SIZE)
116 return -EINVAL;
117 }
118
119 return drm_atomic_helper_check(dev, state);
120 }
121
122 static const struct drm_mode_config_funcs vkms_mode_funcs = {
123 .fb_create = drm_gem_fb_create,
124 .atomic_check = vkms_atomic_check,
125 .atomic_commit = drm_atomic_helper_commit,
126 };
127
128 static const struct drm_mode_config_helper_funcs vkms_mode_config_helpers = {
129 .atomic_commit_tail = vkms_atomic_commit_tail,
130 };
131
vkms_modeset_init(struct vkms_device * vkmsdev)132 static int vkms_modeset_init(struct vkms_device *vkmsdev)
133 {
134 struct drm_device *dev = &vkmsdev->drm;
135 int ret;
136
137 ret = drmm_mode_config_init(dev);
138 if (ret)
139 return ret;
140
141 dev->mode_config.funcs = &vkms_mode_funcs;
142 dev->mode_config.min_width = XRES_MIN;
143 dev->mode_config.min_height = YRES_MIN;
144 dev->mode_config.max_width = XRES_MAX;
145 dev->mode_config.max_height = YRES_MAX;
146 dev->mode_config.cursor_width = 512;
147 dev->mode_config.cursor_height = 512;
148 /*
149 * FIXME: There's a confusion between bpp and depth between this and
150 * fbdev helpers. We have to go with 0, meaning "pick the default",
151 * which is XRGB8888 in all cases.
152 */
153 dev->mode_config.preferred_depth = 0;
154 dev->mode_config.helper_private = &vkms_mode_config_helpers;
155
156 return vkms_output_init(vkmsdev);
157 }
158
vkms_create(struct vkms_config * config)159 int vkms_create(struct vkms_config *config)
160 {
161 int ret;
162 struct faux_device *fdev;
163 struct vkms_device *vkms_device;
164 const char *dev_name;
165
166 dev_name = vkms_config_get_device_name(config);
167 fdev = faux_device_create(dev_name, NULL, NULL);
168 if (!fdev)
169 return -ENODEV;
170
171 if (!devres_open_group(&fdev->dev, NULL, GFP_KERNEL)) {
172 ret = -ENOMEM;
173 goto out_unregister;
174 }
175
176 vkms_device = devm_drm_dev_alloc(&fdev->dev, &vkms_driver,
177 struct vkms_device, drm);
178 if (IS_ERR(vkms_device)) {
179 ret = PTR_ERR(vkms_device);
180 goto out_devres;
181 }
182 vkms_device->faux_dev = fdev;
183 vkms_device->config = config;
184 config->dev = vkms_device;
185
186 ret = dma_coerce_mask_and_coherent(vkms_device->drm.dev,
187 DMA_BIT_MASK(64));
188
189 if (ret) {
190 DRM_ERROR("Could not initialize DMA support\n");
191 goto out_devres;
192 }
193
194 ret = drm_vblank_init(&vkms_device->drm,
195 vkms_config_get_num_crtcs(config));
196 if (ret) {
197 DRM_ERROR("Failed to vblank\n");
198 goto out_devres;
199 }
200
201 ret = vkms_modeset_init(vkms_device);
202 if (ret)
203 goto out_devres;
204
205 vkms_config_register_debugfs(vkms_device);
206
207 ret = drm_dev_register(&vkms_device->drm, 0);
208 if (ret)
209 goto out_devres;
210
211 drm_client_setup(&vkms_device->drm, NULL);
212
213 return 0;
214
215 out_devres:
216 devres_release_group(&fdev->dev, NULL);
217 out_unregister:
218 faux_device_destroy(fdev);
219 return ret;
220 }
221
vkms_init(void)222 static int __init vkms_init(void)
223 {
224 int ret;
225 struct vkms_config *config;
226
227 ret = vkms_configfs_register();
228 if (ret)
229 return ret;
230
231 if (!create_default_dev)
232 return 0;
233
234 config = vkms_config_default_create(enable_cursor, enable_writeback,
235 enable_overlay, enable_plane_pipeline);
236 if (IS_ERR(config))
237 return PTR_ERR(config);
238
239 ret = vkms_create(config);
240 if (ret) {
241 vkms_config_destroy(config);
242 return ret;
243 }
244
245 default_config = config;
246
247 return 0;
248 }
249
vkms_destroy(struct vkms_config * config)250 void vkms_destroy(struct vkms_config *config)
251 {
252 struct faux_device *fdev;
253
254 if (!config->dev) {
255 DRM_INFO("vkms_device is NULL.\n");
256 return;
257 }
258
259 fdev = config->dev->faux_dev;
260
261 drm_colorop_pipeline_destroy(&config->dev->drm);
262 drm_dev_unregister(&config->dev->drm);
263 drm_atomic_helper_shutdown(&config->dev->drm);
264 devres_release_group(&fdev->dev, NULL);
265 faux_device_destroy(fdev);
266
267 config->dev = NULL;
268 }
269
vkms_exit(void)270 static void __exit vkms_exit(void)
271 {
272 vkms_configfs_unregister();
273
274 if (!default_config)
275 return;
276
277 vkms_destroy(default_config);
278 vkms_config_destroy(default_config);
279 }
280
281 module_init(vkms_init);
282 module_exit(vkms_exit);
283
284 MODULE_AUTHOR("Haneen Mohammed <hamohammed.sa@gmail.com>");
285 MODULE_AUTHOR("Rodrigo Siqueira <rodrigosiqueiramelo@gmail.com>");
286 MODULE_DESCRIPTION(DRIVER_DESC);
287 MODULE_LICENSE("GPL");
288