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(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, 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
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, "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
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, 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, -1, NULL, 0);
183	if (IS_ERR(pdev))
184		return PTR_ERR(pdev);
185
186	if (!devres_open_group(&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(vkms_device)) {
194		ret = PTR_ERR(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(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(&vkms_device->drm, 1);
210	if (ret) {
211		DRM_ERROR("Failed to vblank\n");
212		goto out_devres;
213	}
214
215	ret = vkms_modeset_init(vkms_device);
216	if (ret)
217		goto out_devres;
218
219	drm_debugfs_add_files(&vkms_device->drm, vkms_config_debugfs_list,
220			      ARRAY_SIZE(vkms_config_debugfs_list));
221
222	ret = drm_dev_register(&vkms_device->drm, 0);
223	if (ret)
224		goto out_devres;
225
226	drm_fbdev_generic_setup(&vkms_device->drm, 0);
227
228	return 0;
229
230out_devres:
231	devres_release_group(&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(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(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(&config->dev->drm);
271	drm_atomic_helper_shutdown(&config->dev->drm);
272	devres_release_group(&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(default_config);
282
283	kfree(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