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	destroy_workqueue(vkms->output.composer_workq);
 61}
 62
 63static void vkms_atomic_commit_tail(struct drm_atomic_state *old_state)
 64{
 65	struct drm_device *dev = old_state->dev;
 66	struct drm_crtc *crtc;
 67	struct drm_crtc_state *old_crtc_state;
 68	int i;
 69
 70	drm_atomic_helper_commit_modeset_disables(dev, old_state);
 71
 72	drm_atomic_helper_commit_planes(dev, old_state, 0);
 73
 74	drm_atomic_helper_commit_modeset_enables(dev, old_state);
 75
 76	drm_atomic_helper_fake_vblank(old_state);
 77
 78	drm_atomic_helper_commit_hw_done(old_state);
 79
 80	drm_atomic_helper_wait_for_flip_done(dev, old_state);
 81
 82	for_each_old_crtc_in_state(old_state, crtc, old_crtc_state, i) {
 83		struct vkms_crtc_state *vkms_state =
 84			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
 92static int vkms_config_show(struct seq_file *m, void *data)
 93{
 94	struct drm_info_node *node = (struct drm_info_node *)m->private;
 95	struct drm_device *dev = node->minor->dev;
 96	struct vkms_device *vkmsdev = drm_device_to_vkms_device(dev);
 97
 98	seq_printf(m, "writeback=%d\n", vkmsdev->config->writeback);
 99	seq_printf(m, "cursor=%d\n", vkmsdev->config->cursor);
100	seq_printf(m, "overlay=%d\n", vkmsdev->config->overlay);
101
102	return 0;
103}
104
105static const struct drm_info_list vkms_config_debugfs_list[] = {
106	{ "vkms_config", vkms_config_show, 0 },
107};
108
109static void vkms_config_debugfs_init(struct drm_minor *minor)
110{
111	drm_debugfs_create_files(vkms_config_debugfs_list, ARRAY_SIZE(vkms_config_debugfs_list),
112				 minor->debugfs_root, minor);
113}
114
115static const struct drm_driver vkms_driver = {
116	.driver_features	= DRIVER_MODESET | DRIVER_ATOMIC | DRIVER_GEM,
117	.release		= vkms_release,
118	.fops			= &vkms_driver_fops,
119	DRM_GEM_SHMEM_DRIVER_OPS,
120
121	.debugfs_init           = vkms_config_debugfs_init,
122
123	.name			= DRIVER_NAME,
124	.desc			= DRIVER_DESC,
125	.date			= DRIVER_DATE,
126	.major			= DRIVER_MAJOR,
127	.minor			= DRIVER_MINOR,
128};
129
130static const struct drm_mode_config_funcs vkms_mode_funcs = {
131	.fb_create = drm_gem_fb_create,
132	.atomic_check = drm_atomic_helper_check,
133	.atomic_commit = drm_atomic_helper_commit,
134};
135
136static const struct drm_mode_config_helper_funcs vkms_mode_config_helpers = {
137	.atomic_commit_tail = vkms_atomic_commit_tail,
138};
139
140static int vkms_modeset_init(struct vkms_device *vkmsdev)
141{
142	struct drm_device *dev = &vkmsdev->drm;
143
144	drm_mode_config_init(dev);
145	dev->mode_config.funcs = &vkms_mode_funcs;
146	dev->mode_config.min_width = XRES_MIN;
147	dev->mode_config.min_height = YRES_MIN;
148	dev->mode_config.max_width = XRES_MAX;
149	dev->mode_config.max_height = YRES_MAX;
150	dev->mode_config.cursor_width = 512;
151	dev->mode_config.cursor_height = 512;
152	/* FIXME: There's a confusion between bpp and depth between this and
153	 * fbdev helpers. We have to go with 0, meaning "pick the default",
154	 * which ix XRGB8888 in all cases. */
155	dev->mode_config.preferred_depth = 0;
156	dev->mode_config.helper_private = &vkms_mode_config_helpers;
157
158	return vkms_output_init(vkmsdev, 0);
159}
160
161static int vkms_create(struct vkms_config *config)
162{
163	int ret;
164	struct platform_device *pdev;
165	struct vkms_device *vkms_device;
166
167	pdev = platform_device_register_simple(DRIVER_NAME, -1, NULL, 0);
168	if (IS_ERR(pdev))
169		return PTR_ERR(pdev);
170
171	if (!devres_open_group(&pdev->dev, NULL, GFP_KERNEL)) {
172		ret = -ENOMEM;
173		goto out_unregister;
174	}
175
176	vkms_device = devm_drm_dev_alloc(&pdev->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->platform = pdev;
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, 1);
195	if (ret) {
196		DRM_ERROR("Failed to vblank\n");
197		goto out_devres;
198	}
199
200	ret = vkms_modeset_init(vkms_device);
201	if (ret)
202		goto out_devres;
203
204	ret = drm_dev_register(&vkms_device->drm, 0);
205	if (ret)
206		goto out_devres;
207
208	drm_fbdev_generic_setup(&vkms_device->drm, 0);
209
210	return 0;
211
212out_devres:
213	devres_release_group(&pdev->dev, NULL);
214out_unregister:
215	platform_device_unregister(pdev);
216	return ret;
217}
218
219static int __init vkms_init(void)
220{
221	struct vkms_config *config;
222
223	config = kmalloc(sizeof(*config), GFP_KERNEL);
224	if (!config)
225		return -ENOMEM;
226
227	default_config = config;
228
229	config->cursor = enable_cursor;
230	config->writeback = enable_writeback;
231	config->overlay = enable_overlay;
232
233	return vkms_create(config);
234}
235
236static void vkms_destroy(struct vkms_config *config)
237{
238	struct platform_device *pdev;
239
240	if (!config->dev) {
241		DRM_INFO("vkms_device is NULL.\n");
242		return;
243	}
244
245	pdev = config->dev->platform;
246
247	drm_dev_unregister(&config->dev->drm);
248	drm_atomic_helper_shutdown(&config->dev->drm);
249	devres_release_group(&pdev->dev, NULL);
250	platform_device_unregister(pdev);
251
252	config->dev = NULL;
253}
254
255static void __exit vkms_exit(void)
256{
257	if (default_config->dev)
258		vkms_destroy(default_config);
259
260	kfree(default_config);
261}
262
263module_init(vkms_init);
264module_exit(vkms_exit);
265
266MODULE_AUTHOR("Haneen Mohammed <hamohammed.sa@gmail.com>");
267MODULE_AUTHOR("Rodrigo Siqueira <rodrigosiqueiramelo@gmail.com>");
268MODULE_DESCRIPTION(DRIVER_DESC);
269MODULE_LICENSE("GPL");