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/drm_gem.h>
17 #include <drm/drm_atomic.h>
18 #include <drm/drm_atomic_helper.h>
19 #include <drm/drm_drv.h>
20 #include <drm/drm_fbdev_shmem.h>
21 #include <drm/drm_file.h>
22 #include <drm/drm_gem_framebuffer_helper.h>
23 #include <drm/drm_ioctl.h>
24 #include <drm/drm_managed.h>
25 #include <drm/drm_probe_helper.h>
26 #include <drm/drm_gem_shmem_helper.h>
27 #include <drm/drm_vblank.h>
28
29 #include "vkms_drv.h"
30
31 #include <drm/drm_print.h>
32 #include <drm/drm_debugfs.h>
33
34 #define DRIVER_NAME "vkms"
35 #define DRIVER_DESC "Virtual Kernel Mode Setting"
36 #define DRIVER_DATE "20180514"
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 =
85 to_vkms_crtc_state(old_crtc_state);
86
87 flush_work(&vkms_state->composer_work);
88 }
89
90 drm_atomic_helper_cleanup_planes(dev, old_state);
91 }
92
vkms_config_show(struct seq_file * m,void * data)93 static int vkms_config_show(struct seq_file *m, void *data)
94 {
95 struct drm_debugfs_entry *entry = m->private;
96 struct drm_device *dev = entry->dev;
97 struct vkms_device *vkmsdev = drm_device_to_vkms_device(dev);
98
99 seq_printf(m, "writeback=%d\n", vkmsdev->config->writeback);
100 seq_printf(m, "cursor=%d\n", vkmsdev->config->cursor);
101 seq_printf(m, "overlay=%d\n", vkmsdev->config->overlay);
102
103 return 0;
104 }
105
106 static const struct drm_debugfs_info vkms_config_debugfs_list[] = {
107 { "vkms_config", vkms_config_show, 0 },
108 };
109
110 static const struct drm_driver vkms_driver = {
111 .driver_features = DRIVER_MODESET | DRIVER_ATOMIC | DRIVER_GEM,
112 .release = vkms_release,
113 .fops = &vkms_driver_fops,
114 DRM_GEM_SHMEM_DRIVER_OPS,
115
116 .name = DRIVER_NAME,
117 .desc = DRIVER_DESC,
118 .date = DRIVER_DATE,
119 .major = DRIVER_MAJOR,
120 .minor = DRIVER_MINOR,
121 };
122
vkms_atomic_check(struct drm_device * dev,struct drm_atomic_state * state)123 static int vkms_atomic_check(struct drm_device *dev, struct drm_atomic_state *state)
124 {
125 struct drm_crtc *crtc;
126 struct drm_crtc_state *new_crtc_state;
127 int i;
128
129 for_each_new_crtc_in_state(state, crtc, new_crtc_state, i) {
130 if (!new_crtc_state->gamma_lut || !new_crtc_state->color_mgmt_changed)
131 continue;
132
133 if (new_crtc_state->gamma_lut->length / sizeof(struct drm_color_lut *)
134 > VKMS_LUT_SIZE)
135 return -EINVAL;
136 }
137
138 return drm_atomic_helper_check(dev, state);
139 }
140
141 static const struct drm_mode_config_funcs vkms_mode_funcs = {
142 .fb_create = drm_gem_fb_create,
143 .atomic_check = vkms_atomic_check,
144 .atomic_commit = drm_atomic_helper_commit,
145 };
146
147 static const struct drm_mode_config_helper_funcs vkms_mode_config_helpers = {
148 .atomic_commit_tail = vkms_atomic_commit_tail,
149 };
150
vkms_modeset_init(struct vkms_device * vkmsdev)151 static int vkms_modeset_init(struct vkms_device *vkmsdev)
152 {
153 struct drm_device *dev = &vkmsdev->drm;
154 int ret;
155
156 ret = drmm_mode_config_init(dev);
157 if (ret)
158 return ret;
159
160 dev->mode_config.funcs = &vkms_mode_funcs;
161 dev->mode_config.min_width = XRES_MIN;
162 dev->mode_config.min_height = YRES_MIN;
163 dev->mode_config.max_width = XRES_MAX;
164 dev->mode_config.max_height = YRES_MAX;
165 dev->mode_config.cursor_width = 512;
166 dev->mode_config.cursor_height = 512;
167 /*
168 * FIXME: There's a confusion between bpp and depth between this and
169 * fbdev helpers. We have to go with 0, meaning "pick the default",
170 * which is XRGB8888 in all cases.
171 */
172 dev->mode_config.preferred_depth = 0;
173 dev->mode_config.helper_private = &vkms_mode_config_helpers;
174
175 return vkms_output_init(vkmsdev, 0);
176 }
177
vkms_create(struct vkms_config * config)178 static int vkms_create(struct vkms_config *config)
179 {
180 int ret;
181 struct platform_device *pdev;
182 struct vkms_device *vkms_device;
183
184 pdev = platform_device_register_simple(DRIVER_NAME, -1, NULL, 0);
185 if (IS_ERR(pdev))
186 return PTR_ERR(pdev);
187
188 if (!devres_open_group(&pdev->dev, NULL, GFP_KERNEL)) {
189 ret = -ENOMEM;
190 goto out_unregister;
191 }
192
193 vkms_device = devm_drm_dev_alloc(&pdev->dev, &vkms_driver,
194 struct vkms_device, drm);
195 if (IS_ERR(vkms_device)) {
196 ret = PTR_ERR(vkms_device);
197 goto out_devres;
198 }
199 vkms_device->platform = pdev;
200 vkms_device->config = config;
201 config->dev = vkms_device;
202
203 ret = dma_coerce_mask_and_coherent(vkms_device->drm.dev,
204 DMA_BIT_MASK(64));
205
206 if (ret) {
207 DRM_ERROR("Could not initialize DMA support\n");
208 goto out_devres;
209 }
210
211 ret = drm_vblank_init(&vkms_device->drm, 1);
212 if (ret) {
213 DRM_ERROR("Failed to vblank\n");
214 goto out_devres;
215 }
216
217 ret = vkms_modeset_init(vkms_device);
218 if (ret)
219 goto out_devres;
220
221 drm_debugfs_add_files(&vkms_device->drm, vkms_config_debugfs_list,
222 ARRAY_SIZE(vkms_config_debugfs_list));
223
224 ret = drm_dev_register(&vkms_device->drm, 0);
225 if (ret)
226 goto out_devres;
227
228 drm_fbdev_shmem_setup(&vkms_device->drm, 0);
229
230 return 0;
231
232 out_devres:
233 devres_release_group(&pdev->dev, NULL);
234 out_unregister:
235 platform_device_unregister(pdev);
236 return ret;
237 }
238
vkms_init(void)239 static int __init vkms_init(void)
240 {
241 int ret;
242 struct vkms_config *config;
243
244 config = kmalloc(sizeof(*config), GFP_KERNEL);
245 if (!config)
246 return -ENOMEM;
247
248 default_config = config;
249
250 config->cursor = enable_cursor;
251 config->writeback = enable_writeback;
252 config->overlay = enable_overlay;
253
254 ret = vkms_create(config);
255 if (ret)
256 kfree(config);
257
258 return ret;
259 }
260
vkms_destroy(struct vkms_config * config)261 static void vkms_destroy(struct vkms_config *config)
262 {
263 struct platform_device *pdev;
264
265 if (!config->dev) {
266 DRM_INFO("vkms_device is NULL.\n");
267 return;
268 }
269
270 pdev = config->dev->platform;
271
272 drm_dev_unregister(&config->dev->drm);
273 drm_atomic_helper_shutdown(&config->dev->drm);
274 devres_release_group(&pdev->dev, NULL);
275 platform_device_unregister(pdev);
276
277 config->dev = NULL;
278 }
279
vkms_exit(void)280 static void __exit vkms_exit(void)
281 {
282 if (default_config->dev)
283 vkms_destroy(default_config);
284
285 kfree(default_config);
286 }
287
288 module_init(vkms_init);
289 module_exit(vkms_exit);
290
291 MODULE_AUTHOR("Haneen Mohammed <hamohammed.sa@gmail.com>");
292 MODULE_AUTHOR("Rodrigo Siqueira <rodrigosiqueiramelo@gmail.com>");
293 MODULE_DESCRIPTION(DRIVER_DESC);
294 MODULE_LICENSE("GPL");
295