xref: /openbmc/linux/drivers/gpu/drm/vkms/vkms_drv.c (revision db1f254f)
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 
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 	/* 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 
vkms_create(struct vkms_config * config)176 static 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 
230 out_devres:
231 	devres_release_group(&pdev->dev, NULL);
232 out_unregister:
233 	platform_device_unregister(pdev);
234 	return ret;
235 }
236 
vkms_init(void)237 static 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 
vkms_destroy(struct vkms_config * config)259 static 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 
vkms_exit(void)278 static void __exit vkms_exit(void)
279 {
280 	if (default_config->dev)
281 		vkms_destroy(default_config);
282 
283 	kfree(default_config);
284 }
285 
286 module_init(vkms_init);
287 module_exit(vkms_exit);
288 
289 MODULE_AUTHOR("Haneen Mohammed <hamohammed.sa@gmail.com>");
290 MODULE_AUTHOR("Rodrigo Siqueira <rodrigosiqueiramelo@gmail.com>");
291 MODULE_DESCRIPTION(DRIVER_DESC);
292 MODULE_LICENSE("GPL");
293