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/device/faux.h> 14 #include <linux/dma-mapping.h> 15 16 #include <drm/clients/drm_client_setup.h> 17 #include <drm/drm_gem.h> 18 #include <drm/drm_atomic.h> 19 #include <drm/drm_atomic_helper.h> 20 #include <drm/drm_drv.h> 21 #include <drm/drm_fbdev_shmem.h> 22 #include <drm/drm_file.h> 23 #include <drm/drm_gem_framebuffer_helper.h> 24 #include <drm/drm_ioctl.h> 25 #include <drm/drm_managed.h> 26 #include <drm/drm_probe_helper.h> 27 #include <drm/drm_gem_shmem_helper.h> 28 #include <drm/drm_vblank.h> 29 30 #include "vkms_config.h" 31 #include "vkms_configfs.h" 32 #include "vkms_drv.h" 33 34 #define DRIVER_NAME "vkms" 35 #define DRIVER_DESC "Virtual Kernel Mode Setting" 36 #define DRIVER_MAJOR 1 37 #define DRIVER_MINOR 0 38 39 static struct vkms_config *default_config; 40 41 static bool enable_cursor = true; 42 module_param_named(enable_cursor, enable_cursor, bool, 0444); 43 MODULE_PARM_DESC(enable_cursor, "Enable/Disable cursor support"); 44 45 static bool enable_writeback = true; 46 module_param_named(enable_writeback, enable_writeback, bool, 0444); 47 MODULE_PARM_DESC(enable_writeback, "Enable/Disable writeback connector support"); 48 49 static bool enable_overlay; 50 module_param_named(enable_overlay, enable_overlay, bool, 0444); 51 MODULE_PARM_DESC(enable_overlay, "Enable/Disable overlay support"); 52 53 static bool create_default_dev = true; 54 module_param_named(create_default_dev, create_default_dev, bool, 0444); 55 MODULE_PARM_DESC(create_default_dev, "Create or not the default VKMS device"); 56 57 DEFINE_DRM_GEM_FOPS(vkms_driver_fops); 58 59 static void vkms_atomic_commit_tail(struct drm_atomic_state *old_state) 60 { 61 struct drm_device *dev = old_state->dev; 62 struct drm_crtc *crtc; 63 struct drm_crtc_state *old_crtc_state; 64 int i; 65 66 drm_atomic_helper_commit_modeset_disables(dev, old_state); 67 68 drm_atomic_helper_commit_planes(dev, old_state, 0); 69 70 drm_atomic_helper_commit_modeset_enables(dev, old_state); 71 72 drm_atomic_helper_fake_vblank(old_state); 73 74 drm_atomic_helper_commit_hw_done(old_state); 75 76 drm_atomic_helper_wait_for_flip_done(dev, old_state); 77 78 for_each_old_crtc_in_state(old_state, crtc, old_crtc_state, i) { 79 struct vkms_crtc_state *vkms_state = to_vkms_crtc_state(old_crtc_state); 80 81 flush_work(&vkms_state->composer_work); 82 } 83 84 drm_atomic_helper_cleanup_planes(dev, old_state); 85 } 86 87 static const struct drm_driver vkms_driver = { 88 .driver_features = DRIVER_MODESET | DRIVER_ATOMIC | DRIVER_GEM, 89 .fops = &vkms_driver_fops, 90 DRM_GEM_SHMEM_DRIVER_OPS, 91 DRM_FBDEV_SHMEM_DRIVER_OPS, 92 93 .name = DRIVER_NAME, 94 .desc = DRIVER_DESC, 95 .major = DRIVER_MAJOR, 96 .minor = DRIVER_MINOR, 97 }; 98 99 static int vkms_atomic_check(struct drm_device *dev, struct drm_atomic_state *state) 100 { 101 struct drm_crtc *crtc; 102 struct drm_crtc_state *new_crtc_state; 103 int i; 104 105 for_each_new_crtc_in_state(state, crtc, new_crtc_state, i) { 106 if (!new_crtc_state->gamma_lut || !new_crtc_state->color_mgmt_changed) 107 continue; 108 109 if (new_crtc_state->gamma_lut->length / sizeof(struct drm_color_lut *) 110 > VKMS_LUT_SIZE) 111 return -EINVAL; 112 } 113 114 return drm_atomic_helper_check(dev, state); 115 } 116 117 static const struct drm_mode_config_funcs vkms_mode_funcs = { 118 .fb_create = drm_gem_fb_create, 119 .atomic_check = vkms_atomic_check, 120 .atomic_commit = drm_atomic_helper_commit, 121 }; 122 123 static const struct drm_mode_config_helper_funcs vkms_mode_config_helpers = { 124 .atomic_commit_tail = vkms_atomic_commit_tail, 125 }; 126 127 static int vkms_modeset_init(struct vkms_device *vkmsdev) 128 { 129 struct drm_device *dev = &vkmsdev->drm; 130 int ret; 131 132 ret = drmm_mode_config_init(dev); 133 if (ret) 134 return ret; 135 136 dev->mode_config.funcs = &vkms_mode_funcs; 137 dev->mode_config.min_width = XRES_MIN; 138 dev->mode_config.min_height = YRES_MIN; 139 dev->mode_config.max_width = XRES_MAX; 140 dev->mode_config.max_height = YRES_MAX; 141 dev->mode_config.cursor_width = 512; 142 dev->mode_config.cursor_height = 512; 143 /* 144 * FIXME: There's a confusion between bpp and depth between this and 145 * fbdev helpers. We have to go with 0, meaning "pick the default", 146 * which is XRGB8888 in all cases. 147 */ 148 dev->mode_config.preferred_depth = 0; 149 dev->mode_config.helper_private = &vkms_mode_config_helpers; 150 151 return vkms_output_init(vkmsdev); 152 } 153 154 int vkms_create(struct vkms_config *config) 155 { 156 int ret; 157 struct faux_device *fdev; 158 struct vkms_device *vkms_device; 159 const char *dev_name; 160 161 dev_name = vkms_config_get_device_name(config); 162 fdev = faux_device_create(dev_name, NULL, NULL); 163 if (!fdev) 164 return -ENODEV; 165 166 if (!devres_open_group(&fdev->dev, NULL, GFP_KERNEL)) { 167 ret = -ENOMEM; 168 goto out_unregister; 169 } 170 171 vkms_device = devm_drm_dev_alloc(&fdev->dev, &vkms_driver, 172 struct vkms_device, drm); 173 if (IS_ERR(vkms_device)) { 174 ret = PTR_ERR(vkms_device); 175 goto out_devres; 176 } 177 vkms_device->faux_dev = fdev; 178 vkms_device->config = config; 179 config->dev = vkms_device; 180 181 ret = dma_coerce_mask_and_coherent(vkms_device->drm.dev, 182 DMA_BIT_MASK(64)); 183 184 if (ret) { 185 DRM_ERROR("Could not initialize DMA support\n"); 186 goto out_devres; 187 } 188 189 ret = drm_vblank_init(&vkms_device->drm, 190 vkms_config_get_num_crtcs(config)); 191 if (ret) { 192 DRM_ERROR("Failed to vblank\n"); 193 goto out_devres; 194 } 195 196 ret = vkms_modeset_init(vkms_device); 197 if (ret) 198 goto out_devres; 199 200 vkms_config_register_debugfs(vkms_device); 201 202 ret = drm_dev_register(&vkms_device->drm, 0); 203 if (ret) 204 goto out_devres; 205 206 drm_client_setup(&vkms_device->drm, NULL); 207 208 return 0; 209 210 out_devres: 211 devres_release_group(&fdev->dev, NULL); 212 out_unregister: 213 faux_device_destroy(fdev); 214 return ret; 215 } 216 217 static int __init vkms_init(void) 218 { 219 int ret; 220 struct vkms_config *config; 221 222 ret = vkms_configfs_register(); 223 if (ret) 224 return ret; 225 226 if (!create_default_dev) 227 return 0; 228 229 config = vkms_config_default_create(enable_cursor, enable_writeback, enable_overlay); 230 if (IS_ERR(config)) 231 return PTR_ERR(config); 232 233 ret = vkms_create(config); 234 if (ret) { 235 vkms_config_destroy(config); 236 return ret; 237 } 238 239 default_config = config; 240 241 return 0; 242 } 243 244 void vkms_destroy(struct vkms_config *config) 245 { 246 struct faux_device *fdev; 247 248 if (!config->dev) { 249 DRM_INFO("vkms_device is NULL.\n"); 250 return; 251 } 252 253 fdev = config->dev->faux_dev; 254 255 drm_dev_unregister(&config->dev->drm); 256 drm_atomic_helper_shutdown(&config->dev->drm); 257 devres_release_group(&fdev->dev, NULL); 258 faux_device_destroy(fdev); 259 260 config->dev = NULL; 261 } 262 263 static void __exit vkms_exit(void) 264 { 265 vkms_configfs_unregister(); 266 267 if (!default_config) 268 return; 269 270 vkms_destroy(default_config); 271 vkms_config_destroy(default_config); 272 } 273 274 module_init(vkms_init); 275 module_exit(vkms_exit); 276 277 MODULE_AUTHOR("Haneen Mohammed <hamohammed.sa@gmail.com>"); 278 MODULE_AUTHOR("Rodrigo Siqueira <rodrigosiqueiramelo@gmail.com>"); 279 MODULE_DESCRIPTION(DRIVER_DESC); 280 MODULE_LICENSE("GPL"); 281