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_generic.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
40static struct vkms_config *default_config;
41
42static bool enable_cursor = true;
43module_param_named(enable_cursor, enable_cursor, bool, 0444);
44MODULE_PARM_DESC(enable_cursor, "Enable/Disable cursor support");
45
46static bool enable_writeback = true;
47module_param_named(enable_writeback, enable_writeback, bool, 0444);
48MODULE_PARM_DESC(enable_writeback, "Enable/Disable writeback connector support");
49
50static bool enable_overlay;
51module_param_named(enable_overlay, enable_overlay, bool, 0444);
52MODULE_PARM_DESC(enable_overlay, "Enable/Disable overlay support");
53
54DEFINE_DRM_GEM_FOPS(vkms_driver_fops);
55
56static 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(wq: vkms->output.composer_workq);
62}
63
64static 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, state: old_state);
72
73 drm_atomic_helper_commit_planes(dev, state: old_state, flags: 0);
74
75 drm_atomic_helper_commit_modeset_enables(dev, old_state);
76
77 drm_atomic_helper_fake_vblank(state: old_state);
78
79 drm_atomic_helper_commit_hw_done(state: 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(work: &vkms_state->composer_work);
88 }
89
90 drm_atomic_helper_cleanup_planes(dev, old_state);
91}
92
93static 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, fmt: "writeback=%d\n", vkmsdev->config->writeback);
100 seq_printf(m, fmt: "cursor=%d\n", vkmsdev->config->cursor);
101 seq_printf(m, fmt: "overlay=%d\n", vkmsdev->config->overlay);
102
103 return 0;
104}
105
106static const struct drm_debugfs_info vkms_config_debugfs_list[] = {
107 { "vkms_config", vkms_config_show, 0 },
108};
109
110static 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
123static 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
141static 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
147static const struct drm_mode_config_helper_funcs vkms_mode_config_helpers = {
148 .atomic_commit_tail = vkms_atomic_commit_tail,
149};
150
151static 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 /* 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 ix XRGB8888 in all cases. */
170 dev->mode_config.preferred_depth = 0;
171 dev->mode_config.helper_private = &vkms_mode_config_helpers;
172
173 return vkms_output_init(vkmsdev, index: 0);
174}
175
176static int vkms_create(struct vkms_config *config)
177{
178 int ret;
179 struct platform_device *pdev;
180 struct vkms_device *vkms_device;
181
182 pdev = platform_device_register_simple(DRIVER_NAME, id: -1, NULL, num: 0);
183 if (IS_ERR(ptr: pdev))
184 return PTR_ERR(ptr: pdev);
185
186 if (!devres_open_group(dev: &pdev->dev, NULL, GFP_KERNEL)) {
187 ret = -ENOMEM;
188 goto out_unregister;
189 }
190
191 vkms_device = devm_drm_dev_alloc(&pdev->dev, &vkms_driver,
192 struct vkms_device, drm);
193 if (IS_ERR(ptr: vkms_device)) {
194 ret = PTR_ERR(ptr: vkms_device);
195 goto out_devres;
196 }
197 vkms_device->platform = pdev;
198 vkms_device->config = config;
199 config->dev = vkms_device;
200
201 ret = dma_coerce_mask_and_coherent(dev: vkms_device->drm.dev,
202 DMA_BIT_MASK(64));
203
204 if (ret) {
205 DRM_ERROR("Could not initialize DMA support\n");
206 goto out_devres;
207 }
208
209 ret = drm_vblank_init(dev: &vkms_device->drm, num_crtcs: 1);
210 if (ret) {
211 DRM_ERROR("Failed to vblank\n");
212 goto out_devres;
213 }
214
215 ret = vkms_modeset_init(vkmsdev: vkms_device);
216 if (ret)
217 goto out_devres;
218
219 drm_debugfs_add_files(dev: &vkms_device->drm, files: vkms_config_debugfs_list,
220 ARRAY_SIZE(vkms_config_debugfs_list));
221
222 ret = drm_dev_register(dev: &vkms_device->drm, flags: 0);
223 if (ret)
224 goto out_devres;
225
226 drm_fbdev_generic_setup(dev: &vkms_device->drm, preferred_bpp: 0);
227
228 return 0;
229
230out_devres:
231 devres_release_group(dev: &pdev->dev, NULL);
232out_unregister:
233 platform_device_unregister(pdev);
234 return ret;
235}
236
237static int __init vkms_init(void)
238{
239 int ret;
240 struct vkms_config *config;
241
242 config = kmalloc(size: sizeof(*config), GFP_KERNEL);
243 if (!config)
244 return -ENOMEM;
245
246 default_config = config;
247
248 config->cursor = enable_cursor;
249 config->writeback = enable_writeback;
250 config->overlay = enable_overlay;
251
252 ret = vkms_create(config);
253 if (ret)
254 kfree(objp: config);
255
256 return ret;
257}
258
259static void vkms_destroy(struct vkms_config *config)
260{
261 struct platform_device *pdev;
262
263 if (!config->dev) {
264 DRM_INFO("vkms_device is NULL.\n");
265 return;
266 }
267
268 pdev = config->dev->platform;
269
270 drm_dev_unregister(dev: &config->dev->drm);
271 drm_atomic_helper_shutdown(dev: &config->dev->drm);
272 devres_release_group(dev: &pdev->dev, NULL);
273 platform_device_unregister(pdev);
274
275 config->dev = NULL;
276}
277
278static void __exit vkms_exit(void)
279{
280 if (default_config->dev)
281 vkms_destroy(config: default_config);
282
283 kfree(objp: default_config);
284}
285
286module_init(vkms_init);
287module_exit(vkms_exit);
288
289MODULE_AUTHOR("Haneen Mohammed <hamohammed.sa@gmail.com>");
290MODULE_AUTHOR("Rodrigo Siqueira <rodrigosiqueiramelo@gmail.com>");
291MODULE_DESCRIPTION(DRIVER_DESC);
292MODULE_LICENSE("GPL");
293

source code of linux/drivers/gpu/drm/vkms/vkms_drv.c