xref: /linux/drivers/gpu/drm/vkms/vkms_drv.c (revision 56fb34d86e875dbb0d3e6a81c5d3d035db373031)
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  * or for running X (or similar) on headless machines and be able to still
8  * use the GPU. vkms aims to enable a virtual display without the need for
9  * a hardware display capability.
10  */
11 
12 #include <linux/module.h>
13 #include <linux/platform_device.h>
14 
15 #include <drm/drm_atomic.h>
16 #include <drm/drm_atomic_helper.h>
17 #include <drm/drm_drv.h>
18 #include <drm/drm_fb_helper.h>
19 #include <drm/drm_file.h>
20 #include <drm/drm_gem.h>
21 #include <drm/drm_gem_framebuffer_helper.h>
22 #include <drm/drm_ioctl.h>
23 #include <drm/drm_probe_helper.h>
24 #include <drm/drm_vblank.h>
25 
26 #include "vkms_drv.h"
27 
28 #define DRIVER_NAME	"vkms"
29 #define DRIVER_DESC	"Virtual Kernel Mode Setting"
30 #define DRIVER_DATE	"20180514"
31 #define DRIVER_MAJOR	1
32 #define DRIVER_MINOR	0
33 
34 static struct vkms_device *vkms_device;
35 
36 bool enable_cursor;
37 module_param_named(enable_cursor, enable_cursor, bool, 0444);
38 MODULE_PARM_DESC(enable_cursor, "Enable/Disable cursor support");
39 
40 static const struct file_operations vkms_driver_fops = {
41 	.owner		= THIS_MODULE,
42 	.open		= drm_open,
43 	.mmap		= drm_gem_mmap,
44 	.unlocked_ioctl	= drm_ioctl,
45 	.compat_ioctl	= drm_compat_ioctl,
46 	.poll		= drm_poll,
47 	.read		= drm_read,
48 	.llseek		= no_llseek,
49 	.release	= drm_release,
50 };
51 
52 static const struct vm_operations_struct vkms_gem_vm_ops = {
53 	.fault = vkms_gem_fault,
54 	.open = drm_gem_vm_open,
55 	.close = drm_gem_vm_close,
56 };
57 
58 static void vkms_release(struct drm_device *dev)
59 {
60 	struct vkms_device *vkms = container_of(dev, struct vkms_device, drm);
61 
62 	platform_device_unregister(vkms->platform);
63 	drm_atomic_helper_shutdown(&vkms->drm);
64 	drm_mode_config_cleanup(&vkms->drm);
65 	drm_dev_fini(&vkms->drm);
66 	destroy_workqueue(vkms->output.composer_workq);
67 }
68 
69 static void vkms_atomic_commit_tail(struct drm_atomic_state *old_state)
70 {
71 	struct drm_device *dev = old_state->dev;
72 	struct drm_crtc *crtc;
73 	struct drm_crtc_state *old_crtc_state;
74 	int i;
75 
76 	drm_atomic_helper_commit_modeset_disables(dev, old_state);
77 
78 	drm_atomic_helper_commit_planes(dev, old_state, 0);
79 
80 	drm_atomic_helper_commit_modeset_enables(dev, old_state);
81 
82 	drm_atomic_helper_fake_vblank(old_state);
83 
84 	drm_atomic_helper_commit_hw_done(old_state);
85 
86 	drm_atomic_helper_wait_for_vblanks(dev, old_state);
87 
88 	for_each_old_crtc_in_state(old_state, crtc, old_crtc_state, i) {
89 		struct vkms_crtc_state *vkms_state =
90 			to_vkms_crtc_state(old_crtc_state);
91 
92 		flush_work(&vkms_state->composer_work);
93 	}
94 
95 	drm_atomic_helper_cleanup_planes(dev, old_state);
96 }
97 
98 static struct drm_driver vkms_driver = {
99 	.driver_features	= DRIVER_MODESET | DRIVER_ATOMIC | DRIVER_GEM,
100 	.release		= vkms_release,
101 	.fops			= &vkms_driver_fops,
102 	.dumb_create		= vkms_dumb_create,
103 	.gem_vm_ops		= &vkms_gem_vm_ops,
104 	.gem_free_object_unlocked = vkms_gem_free_object,
105 	.get_vblank_timestamp	= vkms_get_vblank_timestamp,
106 
107 	.name			= DRIVER_NAME,
108 	.desc			= DRIVER_DESC,
109 	.date			= DRIVER_DATE,
110 	.major			= DRIVER_MAJOR,
111 	.minor			= DRIVER_MINOR,
112 };
113 
114 static const struct drm_mode_config_funcs vkms_mode_funcs = {
115 	.fb_create = drm_gem_fb_create,
116 	.atomic_check = drm_atomic_helper_check,
117 	.atomic_commit = drm_atomic_helper_commit,
118 };
119 
120 static const struct drm_mode_config_helper_funcs vkms_mode_config_helpers = {
121 	.atomic_commit_tail = vkms_atomic_commit_tail,
122 };
123 
124 static int vkms_modeset_init(struct vkms_device *vkmsdev)
125 {
126 	struct drm_device *dev = &vkmsdev->drm;
127 
128 	drm_mode_config_init(dev);
129 	dev->mode_config.funcs = &vkms_mode_funcs;
130 	dev->mode_config.min_width = XRES_MIN;
131 	dev->mode_config.min_height = YRES_MIN;
132 	dev->mode_config.max_width = XRES_MAX;
133 	dev->mode_config.max_height = YRES_MAX;
134 	dev->mode_config.preferred_depth = 24;
135 	dev->mode_config.helper_private = &vkms_mode_config_helpers;
136 
137 	return vkms_output_init(vkmsdev, 0);
138 }
139 
140 static int __init vkms_init(void)
141 {
142 	int ret;
143 
144 	vkms_device = kzalloc(sizeof(*vkms_device), GFP_KERNEL);
145 	if (!vkms_device)
146 		return -ENOMEM;
147 
148 	vkms_device->platform =
149 		platform_device_register_simple(DRIVER_NAME, -1, NULL, 0);
150 	if (IS_ERR(vkms_device->platform)) {
151 		ret = PTR_ERR(vkms_device->platform);
152 		goto out_free;
153 	}
154 
155 	ret = drm_dev_init(&vkms_device->drm, &vkms_driver,
156 			   &vkms_device->platform->dev);
157 	if (ret)
158 		goto out_unregister;
159 
160 	vkms_device->drm.irq_enabled = true;
161 
162 	ret = drm_vblank_init(&vkms_device->drm, 1);
163 	if (ret) {
164 		DRM_ERROR("Failed to vblank\n");
165 		goto out_fini;
166 	}
167 
168 	ret = vkms_modeset_init(vkms_device);
169 	if (ret)
170 		goto out_fini;
171 
172 	ret = drm_dev_register(&vkms_device->drm, 0);
173 	if (ret)
174 		goto out_fini;
175 
176 	return 0;
177 
178 out_fini:
179 	drm_dev_fini(&vkms_device->drm);
180 
181 out_unregister:
182 	platform_device_unregister(vkms_device->platform);
183 
184 out_free:
185 	kfree(vkms_device);
186 	return ret;
187 }
188 
189 static void __exit vkms_exit(void)
190 {
191 	if (!vkms_device) {
192 		DRM_INFO("vkms_device is NULL.\n");
193 		return;
194 	}
195 
196 	drm_dev_unregister(&vkms_device->drm);
197 	drm_dev_put(&vkms_device->drm);
198 
199 	kfree(vkms_device);
200 }
201 
202 module_init(vkms_init);
203 module_exit(vkms_exit);
204 
205 MODULE_AUTHOR("Haneen Mohammed <hamohammed.sa@gmail.com>");
206 MODULE_AUTHOR("Rodrigo Siqueira <rodrigosiqueiramelo@gmail.com>");
207 MODULE_DESCRIPTION(DRIVER_DESC);
208 MODULE_LICENSE("GPL");
209