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 create_default_dev = true; 55 module_param_named(create_default_dev, create_default_dev, bool, 0444); 56 MODULE_PARM_DESC(create_default_dev, "Create or not the default VKMS device"); 57 58 DEFINE_DRM_GEM_FOPS(vkms_driver_fops); 59 60 static void vkms_atomic_commit_tail(struct drm_atomic_state *old_state) 61 { 62 struct drm_device *dev = old_state->dev; 63 struct drm_crtc *crtc; 64 struct drm_crtc_state *old_crtc_state; 65 int i; 66 67 drm_atomic_helper_commit_modeset_disables(dev, old_state); 68 69 drm_atomic_helper_commit_planes(dev, old_state, 0); 70 71 drm_atomic_helper_commit_modeset_enables(dev, old_state); 72 73 drm_atomic_helper_fake_vblank(old_state); 74 75 drm_atomic_helper_commit_hw_done(old_state); 76 77 drm_atomic_helper_wait_for_flip_done(dev, old_state); 78 79 for_each_old_crtc_in_state(old_state, crtc, old_crtc_state, i) { 80 struct vkms_crtc_state *vkms_state = to_vkms_crtc_state(old_crtc_state); 81 82 flush_work(&vkms_state->composer_work); 83 } 84 85 drm_atomic_helper_cleanup_planes(dev, old_state); 86 } 87 88 static const struct drm_driver vkms_driver = { 89 .driver_features = DRIVER_MODESET | DRIVER_ATOMIC | DRIVER_GEM, 90 .fops = &vkms_driver_fops, 91 DRM_GEM_SHMEM_DRIVER_OPS, 92 DRM_FBDEV_SHMEM_DRIVER_OPS, 93 94 .name = DRIVER_NAME, 95 .desc = DRIVER_DESC, 96 .major = DRIVER_MAJOR, 97 .minor = DRIVER_MINOR, 98 }; 99 100 static int vkms_atomic_check(struct drm_device *dev, struct drm_atomic_state *state) 101 { 102 struct drm_crtc *crtc; 103 struct drm_crtc_state *new_crtc_state; 104 int i; 105 106 for_each_new_crtc_in_state(state, crtc, new_crtc_state, i) { 107 if (!new_crtc_state->gamma_lut || !new_crtc_state->color_mgmt_changed) 108 continue; 109 110 if (new_crtc_state->gamma_lut->length / sizeof(struct drm_color_lut *) 111 > VKMS_LUT_SIZE) 112 return -EINVAL; 113 } 114 115 return drm_atomic_helper_check(dev, state); 116 } 117 118 static const struct drm_mode_config_funcs vkms_mode_funcs = { 119 .fb_create = drm_gem_fb_create, 120 .atomic_check = vkms_atomic_check, 121 .atomic_commit = drm_atomic_helper_commit, 122 }; 123 124 static const struct drm_mode_config_helper_funcs vkms_mode_config_helpers = { 125 .atomic_commit_tail = vkms_atomic_commit_tail, 126 }; 127 128 static int vkms_modeset_init(struct vkms_device *vkmsdev) 129 { 130 struct drm_device *dev = &vkmsdev->drm; 131 int ret; 132 133 ret = drmm_mode_config_init(dev); 134 if (ret) 135 return ret; 136 137 dev->mode_config.funcs = &vkms_mode_funcs; 138 dev->mode_config.min_width = XRES_MIN; 139 dev->mode_config.min_height = YRES_MIN; 140 dev->mode_config.max_width = XRES_MAX; 141 dev->mode_config.max_height = YRES_MAX; 142 dev->mode_config.cursor_width = 512; 143 dev->mode_config.cursor_height = 512; 144 /* 145 * FIXME: There's a confusion between bpp and depth between this and 146 * fbdev helpers. We have to go with 0, meaning "pick the default", 147 * which is XRGB8888 in all cases. 148 */ 149 dev->mode_config.preferred_depth = 0; 150 dev->mode_config.helper_private = &vkms_mode_config_helpers; 151 152 return vkms_output_init(vkmsdev); 153 } 154 155 int vkms_create(struct vkms_config *config) 156 { 157 int ret; 158 struct faux_device *fdev; 159 struct vkms_device *vkms_device; 160 const char *dev_name; 161 162 dev_name = vkms_config_get_device_name(config); 163 fdev = faux_device_create(dev_name, NULL, NULL); 164 if (!fdev) 165 return -ENODEV; 166 167 if (!devres_open_group(&fdev->dev, NULL, GFP_KERNEL)) { 168 ret = -ENOMEM; 169 goto out_unregister; 170 } 171 172 vkms_device = devm_drm_dev_alloc(&fdev->dev, &vkms_driver, 173 struct vkms_device, drm); 174 if (IS_ERR(vkms_device)) { 175 ret = PTR_ERR(vkms_device); 176 goto out_devres; 177 } 178 vkms_device->faux_dev = fdev; 179 vkms_device->config = config; 180 config->dev = vkms_device; 181 182 ret = dma_coerce_mask_and_coherent(vkms_device->drm.dev, 183 DMA_BIT_MASK(64)); 184 185 if (ret) { 186 DRM_ERROR("Could not initialize DMA support\n"); 187 goto out_devres; 188 } 189 190 ret = drm_vblank_init(&vkms_device->drm, 191 vkms_config_get_num_crtcs(config)); 192 if (ret) { 193 DRM_ERROR("Failed to vblank\n"); 194 goto out_devres; 195 } 196 197 ret = vkms_modeset_init(vkms_device); 198 if (ret) 199 goto out_devres; 200 201 vkms_config_register_debugfs(vkms_device); 202 203 ret = drm_dev_register(&vkms_device->drm, 0); 204 if (ret) 205 goto out_devres; 206 207 drm_client_setup(&vkms_device->drm, NULL); 208 209 return 0; 210 211 out_devres: 212 devres_release_group(&fdev->dev, NULL); 213 out_unregister: 214 faux_device_destroy(fdev); 215 return ret; 216 } 217 218 static int __init vkms_init(void) 219 { 220 int ret; 221 struct vkms_config *config; 222 223 ret = vkms_configfs_register(); 224 if (ret) 225 return ret; 226 227 if (!create_default_dev) 228 return 0; 229 230 config = vkms_config_default_create(enable_cursor, enable_writeback, enable_overlay); 231 if (IS_ERR(config)) 232 return PTR_ERR(config); 233 234 ret = vkms_create(config); 235 if (ret) { 236 vkms_config_destroy(config); 237 return ret; 238 } 239 240 default_config = config; 241 242 return 0; 243 } 244 245 void vkms_destroy(struct vkms_config *config) 246 { 247 struct faux_device *fdev; 248 249 if (!config->dev) { 250 DRM_INFO("vkms_device is NULL.\n"); 251 return; 252 } 253 254 fdev = config->dev->faux_dev; 255 256 drm_dev_unregister(&config->dev->drm); 257 drm_atomic_helper_shutdown(&config->dev->drm); 258 devres_release_group(&fdev->dev, NULL); 259 faux_device_destroy(fdev); 260 261 config->dev = NULL; 262 } 263 264 static void __exit vkms_exit(void) 265 { 266 vkms_configfs_unregister(); 267 268 if (!default_config) 269 return; 270 271 vkms_destroy(default_config); 272 vkms_config_destroy(default_config); 273 } 274 275 module_init(vkms_init); 276 module_exit(vkms_exit); 277 278 MODULE_AUTHOR("Haneen Mohammed <hamohammed.sa@gmail.com>"); 279 MODULE_AUTHOR("Rodrigo Siqueira <rodrigosiqueiramelo@gmail.com>"); 280 MODULE_DESCRIPTION(DRIVER_DESC); 281 MODULE_LICENSE("GPL"); 282