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_print.h> 27 #include <drm/drm_probe_helper.h> 28 #include <drm/drm_gem_shmem_helper.h> 29 #include <drm/drm_vblank.h> 30 31 #include "vkms_config.h" 32 #include "vkms_configfs.h" 33 #include "vkms_drv.h" 34 35 #define DRIVER_NAME "vkms" 36 #define DRIVER_DESC "Virtual Kernel Mode Setting" 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 static bool enable_plane_pipeline; 55 module_param_named(enable_plane_pipeline, enable_plane_pipeline, bool, 0444); 56 MODULE_PARM_DESC(enable_plane_pipeline, "Enable/Disable plane pipeline support"); 57 58 static bool create_default_dev = true; 59 module_param_named(create_default_dev, create_default_dev, bool, 0444); 60 MODULE_PARM_DESC(create_default_dev, "Create or not the default VKMS device"); 61 62 DEFINE_DRM_GEM_FOPS(vkms_driver_fops); 63 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 = 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 92 static const struct drm_driver vkms_driver = { 93 .driver_features = DRIVER_MODESET | DRIVER_ATOMIC | DRIVER_GEM, 94 .fops = &vkms_driver_fops, 95 DRM_GEM_SHMEM_DRIVER_OPS, 96 DRM_FBDEV_SHMEM_DRIVER_OPS, 97 98 .name = DRIVER_NAME, 99 .desc = DRIVER_DESC, 100 .major = DRIVER_MAJOR, 101 .minor = DRIVER_MINOR, 102 }; 103 104 static int vkms_atomic_check(struct drm_device *dev, struct drm_atomic_state *state) 105 { 106 struct drm_crtc *crtc; 107 struct drm_crtc_state *new_crtc_state; 108 int i; 109 110 for_each_new_crtc_in_state(state, crtc, new_crtc_state, i) { 111 if (!new_crtc_state->gamma_lut || !new_crtc_state->color_mgmt_changed) 112 continue; 113 114 if (new_crtc_state->gamma_lut->length / sizeof(struct drm_color_lut *) 115 > VKMS_LUT_SIZE) 116 return -EINVAL; 117 } 118 119 return drm_atomic_helper_check(dev, state); 120 } 121 122 static const struct drm_mode_config_funcs vkms_mode_funcs = { 123 .fb_create = drm_gem_fb_create, 124 .atomic_check = vkms_atomic_check, 125 .atomic_commit = drm_atomic_helper_commit, 126 }; 127 128 static const struct drm_mode_config_helper_funcs vkms_mode_config_helpers = { 129 .atomic_commit_tail = vkms_atomic_commit_tail, 130 }; 131 132 static int vkms_modeset_init(struct vkms_device *vkmsdev) 133 { 134 struct drm_device *dev = &vkmsdev->drm; 135 int ret; 136 137 ret = drmm_mode_config_init(dev); 138 if (ret) 139 return ret; 140 141 dev->mode_config.funcs = &vkms_mode_funcs; 142 dev->mode_config.min_width = XRES_MIN; 143 dev->mode_config.min_height = YRES_MIN; 144 dev->mode_config.max_width = XRES_MAX; 145 dev->mode_config.max_height = YRES_MAX; 146 dev->mode_config.cursor_width = 512; 147 dev->mode_config.cursor_height = 512; 148 /* 149 * FIXME: There's a confusion between bpp and depth between this and 150 * fbdev helpers. We have to go with 0, meaning "pick the default", 151 * which is XRGB8888 in all cases. 152 */ 153 dev->mode_config.preferred_depth = 0; 154 dev->mode_config.helper_private = &vkms_mode_config_helpers; 155 156 return vkms_output_init(vkmsdev); 157 } 158 159 int vkms_create(struct vkms_config *config) 160 { 161 int ret; 162 struct faux_device *fdev; 163 struct vkms_device *vkms_device; 164 const char *dev_name; 165 166 dev_name = vkms_config_get_device_name(config); 167 fdev = faux_device_create(dev_name, NULL, NULL); 168 if (!fdev) 169 return -ENODEV; 170 171 if (!devres_open_group(&fdev->dev, NULL, GFP_KERNEL)) { 172 ret = -ENOMEM; 173 goto out_unregister; 174 } 175 176 vkms_device = devm_drm_dev_alloc(&fdev->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->faux_dev = fdev; 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, 195 vkms_config_get_num_crtcs(config)); 196 if (ret) { 197 DRM_ERROR("Failed to vblank\n"); 198 goto out_devres; 199 } 200 201 ret = vkms_modeset_init(vkms_device); 202 if (ret) 203 goto out_devres; 204 205 vkms_config_register_debugfs(vkms_device); 206 207 ret = drm_dev_register(&vkms_device->drm, 0); 208 if (ret) 209 goto out_devres; 210 211 drm_client_setup(&vkms_device->drm, NULL); 212 213 return 0; 214 215 out_devres: 216 devres_release_group(&fdev->dev, NULL); 217 out_unregister: 218 faux_device_destroy(fdev); 219 return ret; 220 } 221 222 static int __init vkms_init(void) 223 { 224 int ret; 225 struct vkms_config *config; 226 227 ret = vkms_configfs_register(); 228 if (ret) 229 return ret; 230 231 if (!create_default_dev) 232 return 0; 233 234 config = vkms_config_default_create(enable_cursor, enable_writeback, 235 enable_overlay, enable_plane_pipeline); 236 if (IS_ERR(config)) 237 return PTR_ERR(config); 238 239 ret = vkms_create(config); 240 if (ret) { 241 vkms_config_destroy(config); 242 return ret; 243 } 244 245 default_config = config; 246 247 return 0; 248 } 249 250 void vkms_destroy(struct vkms_config *config) 251 { 252 struct faux_device *fdev; 253 254 if (!config->dev) { 255 DRM_INFO("vkms_device is NULL.\n"); 256 return; 257 } 258 259 fdev = config->dev->faux_dev; 260 261 drm_colorop_pipeline_destroy(&config->dev->drm); 262 drm_dev_unregister(&config->dev->drm); 263 drm_atomic_helper_shutdown(&config->dev->drm); 264 devres_release_group(&fdev->dev, NULL); 265 faux_device_destroy(fdev); 266 267 config->dev = NULL; 268 } 269 270 static void __exit vkms_exit(void) 271 { 272 vkms_configfs_unregister(); 273 274 if (!default_config) 275 return; 276 277 vkms_destroy(default_config); 278 vkms_config_destroy(default_config); 279 } 280 281 module_init(vkms_init); 282 module_exit(vkms_exit); 283 284 MODULE_AUTHOR("Haneen Mohammed <hamohammed.sa@gmail.com>"); 285 MODULE_AUTHOR("Rodrigo Siqueira <rodrigosiqueiramelo@gmail.com>"); 286 MODULE_DESCRIPTION(DRIVER_DESC); 287 MODULE_LICENSE("GPL"); 288