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_atomic_commit_tail(struct drm_atomic_state * old_state)56 static void vkms_atomic_commit_tail(struct drm_atomic_state *old_state)
57 {
58 struct drm_device *dev = old_state->dev;
59 struct drm_crtc *crtc;
60 struct drm_crtc_state *old_crtc_state;
61 int i;
62
63 drm_atomic_helper_commit_modeset_disables(dev, old_state);
64
65 drm_atomic_helper_commit_planes(dev, old_state, 0);
66
67 drm_atomic_helper_commit_modeset_enables(dev, old_state);
68
69 drm_atomic_helper_fake_vblank(old_state);
70
71 drm_atomic_helper_commit_hw_done(old_state);
72
73 drm_atomic_helper_wait_for_flip_done(dev, old_state);
74
75 for_each_old_crtc_in_state(old_state, crtc, old_crtc_state, i) {
76 struct vkms_crtc_state *vkms_state = to_vkms_crtc_state(old_crtc_state);
77
78 flush_work(&vkms_state->composer_work);
79 }
80
81 drm_atomic_helper_cleanup_planes(dev, old_state);
82 }
83
vkms_config_show(struct seq_file * m,void * data)84 static int vkms_config_show(struct seq_file *m, void *data)
85 {
86 struct drm_debugfs_entry *entry = m->private;
87 struct drm_device *dev = entry->dev;
88 struct vkms_device *vkmsdev = drm_device_to_vkms_device(dev);
89
90 seq_printf(m, "writeback=%d\n", vkmsdev->config->writeback);
91 seq_printf(m, "cursor=%d\n", vkmsdev->config->cursor);
92 seq_printf(m, "overlay=%d\n", vkmsdev->config->overlay);
93
94 return 0;
95 }
96
97 static const struct drm_debugfs_info vkms_config_debugfs_list[] = {
98 { "vkms_config", vkms_config_show, 0 },
99 };
100
101 static const struct drm_driver vkms_driver = {
102 .driver_features = DRIVER_MODESET | DRIVER_ATOMIC | DRIVER_GEM,
103 .fops = &vkms_driver_fops,
104 DRM_GEM_SHMEM_DRIVER_OPS,
105 DRM_FBDEV_SHMEM_DRIVER_OPS,
106
107 .name = DRIVER_NAME,
108 .desc = DRIVER_DESC,
109 .major = DRIVER_MAJOR,
110 .minor = DRIVER_MINOR,
111 };
112
vkms_atomic_check(struct drm_device * dev,struct drm_atomic_state * state)113 static int vkms_atomic_check(struct drm_device *dev, struct drm_atomic_state *state)
114 {
115 struct drm_crtc *crtc;
116 struct drm_crtc_state *new_crtc_state;
117 int i;
118
119 for_each_new_crtc_in_state(state, crtc, new_crtc_state, i) {
120 if (!new_crtc_state->gamma_lut || !new_crtc_state->color_mgmt_changed)
121 continue;
122
123 if (new_crtc_state->gamma_lut->length / sizeof(struct drm_color_lut *)
124 > VKMS_LUT_SIZE)
125 return -EINVAL;
126 }
127
128 return drm_atomic_helper_check(dev, state);
129 }
130
131 static const struct drm_mode_config_funcs vkms_mode_funcs = {
132 .fb_create = drm_gem_fb_create,
133 .atomic_check = vkms_atomic_check,
134 .atomic_commit = drm_atomic_helper_commit,
135 };
136
137 static const struct drm_mode_config_helper_funcs vkms_mode_config_helpers = {
138 .atomic_commit_tail = vkms_atomic_commit_tail,
139 };
140
vkms_modeset_init(struct vkms_device * vkmsdev)141 static int vkms_modeset_init(struct vkms_device *vkmsdev)
142 {
143 struct drm_device *dev = &vkmsdev->drm;
144 int ret;
145
146 ret = drmm_mode_config_init(dev);
147 if (ret)
148 return ret;
149
150 dev->mode_config.funcs = &vkms_mode_funcs;
151 dev->mode_config.min_width = XRES_MIN;
152 dev->mode_config.min_height = YRES_MIN;
153 dev->mode_config.max_width = XRES_MAX;
154 dev->mode_config.max_height = YRES_MAX;
155 dev->mode_config.cursor_width = 512;
156 dev->mode_config.cursor_height = 512;
157 /*
158 * FIXME: There's a confusion between bpp and depth between this and
159 * fbdev helpers. We have to go with 0, meaning "pick the default",
160 * which is XRGB8888 in all cases.
161 */
162 dev->mode_config.preferred_depth = 0;
163 dev->mode_config.helper_private = &vkms_mode_config_helpers;
164
165 return vkms_output_init(vkmsdev);
166 }
167
vkms_create(struct vkms_config * config)168 static int vkms_create(struct vkms_config *config)
169 {
170 int ret;
171 struct platform_device *pdev;
172 struct vkms_device *vkms_device;
173
174 pdev = platform_device_register_simple(DRIVER_NAME, -1, NULL, 0);
175 if (IS_ERR(pdev))
176 return PTR_ERR(pdev);
177
178 if (!devres_open_group(&pdev->dev, NULL, GFP_KERNEL)) {
179 ret = -ENOMEM;
180 goto out_unregister;
181 }
182
183 vkms_device = devm_drm_dev_alloc(&pdev->dev, &vkms_driver,
184 struct vkms_device, drm);
185 if (IS_ERR(vkms_device)) {
186 ret = PTR_ERR(vkms_device);
187 goto out_devres;
188 }
189 vkms_device->platform = pdev;
190 vkms_device->config = config;
191 config->dev = vkms_device;
192
193 ret = dma_coerce_mask_and_coherent(vkms_device->drm.dev,
194 DMA_BIT_MASK(64));
195
196 if (ret) {
197 DRM_ERROR("Could not initialize DMA support\n");
198 goto out_devres;
199 }
200
201 ret = drm_vblank_init(&vkms_device->drm, 1);
202 if (ret) {
203 DRM_ERROR("Failed to vblank\n");
204 goto out_devres;
205 }
206
207 ret = vkms_modeset_init(vkms_device);
208 if (ret)
209 goto out_devres;
210
211 drm_debugfs_add_files(&vkms_device->drm, vkms_config_debugfs_list,
212 ARRAY_SIZE(vkms_config_debugfs_list));
213
214 ret = drm_dev_register(&vkms_device->drm, 0);
215 if (ret)
216 goto out_devres;
217
218 drm_client_setup(&vkms_device->drm, NULL);
219
220 return 0;
221
222 out_devres:
223 devres_release_group(&pdev->dev, NULL);
224 out_unregister:
225 platform_device_unregister(pdev);
226 return ret;
227 }
228
vkms_init(void)229 static int __init vkms_init(void)
230 {
231 int ret;
232 struct vkms_config *config;
233
234 config = kmalloc(sizeof(*config), GFP_KERNEL);
235 if (!config)
236 return -ENOMEM;
237
238 config->cursor = enable_cursor;
239 config->writeback = enable_writeback;
240 config->overlay = enable_overlay;
241
242 ret = vkms_create(config);
243 if (ret) {
244 kfree(config);
245 return ret;
246 }
247
248 default_config = config;
249
250 return 0;
251 }
252
vkms_destroy(struct vkms_config * config)253 static void vkms_destroy(struct vkms_config *config)
254 {
255 struct platform_device *pdev;
256
257 if (!config->dev) {
258 DRM_INFO("vkms_device is NULL.\n");
259 return;
260 }
261
262 pdev = config->dev->platform;
263
264 drm_dev_unregister(&config->dev->drm);
265 drm_atomic_helper_shutdown(&config->dev->drm);
266 devres_release_group(&pdev->dev, NULL);
267 platform_device_unregister(pdev);
268
269 config->dev = NULL;
270 }
271
vkms_exit(void)272 static void __exit vkms_exit(void)
273 {
274 if (!default_config)
275 return;
276
277 vkms_destroy(default_config);
278 kfree(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