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/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_drv.h" 31 32 #include <drm/drm_print.h> 33 #include <drm/drm_debugfs.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 DEFINE_DRM_GEM_FOPS(vkms_driver_fops); 55 56 static void vkms_atomic_commit_tail(struct drm_atomic_state *old_state) 57 { 58 struct drm_device *dev = old_state->dev; 59 struct drm_crtc *crtc; 60 struct drm_crtc_state *old_crtc_state; 61 int i; 62 63 drm_atomic_helper_commit_modeset_disables(dev, old_state); 64 65 drm_atomic_helper_commit_planes(dev, old_state, 0); 66 67 drm_atomic_helper_commit_modeset_enables(dev, old_state); 68 69 drm_atomic_helper_fake_vblank(old_state); 70 71 drm_atomic_helper_commit_hw_done(old_state); 72 73 drm_atomic_helper_wait_for_flip_done(dev, old_state); 74 75 for_each_old_crtc_in_state(old_state, crtc, old_crtc_state, i) { 76 struct vkms_crtc_state *vkms_state = to_vkms_crtc_state(old_crtc_state); 77 78 flush_work(&vkms_state->composer_work); 79 } 80 81 drm_atomic_helper_cleanup_planes(dev, old_state); 82 } 83 84 static int vkms_config_show(struct seq_file *m, void *data) 85 { 86 struct drm_debugfs_entry *entry = m->private; 87 struct drm_device *dev = entry->dev; 88 struct vkms_device *vkmsdev = drm_device_to_vkms_device(dev); 89 90 seq_printf(m, "writeback=%d\n", vkmsdev->config->writeback); 91 seq_printf(m, "cursor=%d\n", vkmsdev->config->cursor); 92 seq_printf(m, "overlay=%d\n", vkmsdev->config->overlay); 93 94 return 0; 95 } 96 97 static const struct drm_debugfs_info vkms_config_debugfs_list[] = { 98 { "vkms_config", vkms_config_show, 0 }, 99 }; 100 101 static const struct drm_driver vkms_driver = { 102 .driver_features = DRIVER_MODESET | DRIVER_ATOMIC | DRIVER_GEM, 103 .fops = &vkms_driver_fops, 104 DRM_GEM_SHMEM_DRIVER_OPS, 105 DRM_FBDEV_SHMEM_DRIVER_OPS, 106 107 .name = DRIVER_NAME, 108 .desc = DRIVER_DESC, 109 .major = DRIVER_MAJOR, 110 .minor = DRIVER_MINOR, 111 }; 112 113 static int vkms_atomic_check(struct drm_device *dev, struct drm_atomic_state *state) 114 { 115 struct drm_crtc *crtc; 116 struct drm_crtc_state *new_crtc_state; 117 int i; 118 119 for_each_new_crtc_in_state(state, crtc, new_crtc_state, i) { 120 if (!new_crtc_state->gamma_lut || !new_crtc_state->color_mgmt_changed) 121 continue; 122 123 if (new_crtc_state->gamma_lut->length / sizeof(struct drm_color_lut *) 124 > VKMS_LUT_SIZE) 125 return -EINVAL; 126 } 127 128 return drm_atomic_helper_check(dev, state); 129 } 130 131 static const struct drm_mode_config_funcs vkms_mode_funcs = { 132 .fb_create = drm_gem_fb_create, 133 .atomic_check = vkms_atomic_check, 134 .atomic_commit = drm_atomic_helper_commit, 135 }; 136 137 static const struct drm_mode_config_helper_funcs vkms_mode_config_helpers = { 138 .atomic_commit_tail = vkms_atomic_commit_tail, 139 }; 140 141 static int vkms_modeset_init(struct vkms_device *vkmsdev) 142 { 143 struct drm_device *dev = &vkmsdev->drm; 144 int ret; 145 146 ret = drmm_mode_config_init(dev); 147 if (ret) 148 return ret; 149 150 dev->mode_config.funcs = &vkms_mode_funcs; 151 dev->mode_config.min_width = XRES_MIN; 152 dev->mode_config.min_height = YRES_MIN; 153 dev->mode_config.max_width = XRES_MAX; 154 dev->mode_config.max_height = YRES_MAX; 155 dev->mode_config.cursor_width = 512; 156 dev->mode_config.cursor_height = 512; 157 /* 158 * FIXME: There's a confusion between bpp and depth between this and 159 * fbdev helpers. We have to go with 0, meaning "pick the default", 160 * which is XRGB8888 in all cases. 161 */ 162 dev->mode_config.preferred_depth = 0; 163 dev->mode_config.helper_private = &vkms_mode_config_helpers; 164 165 return vkms_output_init(vkmsdev); 166 } 167 168 static int vkms_create(struct vkms_config *config) 169 { 170 int ret; 171 struct platform_device *pdev; 172 struct vkms_device *vkms_device; 173 174 pdev = platform_device_register_simple(DRIVER_NAME, -1, NULL, 0); 175 if (IS_ERR(pdev)) 176 return PTR_ERR(pdev); 177 178 if (!devres_open_group(&pdev->dev, NULL, GFP_KERNEL)) { 179 ret = -ENOMEM; 180 goto out_unregister; 181 } 182 183 vkms_device = devm_drm_dev_alloc(&pdev->dev, &vkms_driver, 184 struct vkms_device, drm); 185 if (IS_ERR(vkms_device)) { 186 ret = PTR_ERR(vkms_device); 187 goto out_devres; 188 } 189 vkms_device->platform = pdev; 190 vkms_device->config = config; 191 config->dev = vkms_device; 192 193 ret = dma_coerce_mask_and_coherent(vkms_device->drm.dev, 194 DMA_BIT_MASK(64)); 195 196 if (ret) { 197 DRM_ERROR("Could not initialize DMA support\n"); 198 goto out_devres; 199 } 200 201 ret = drm_vblank_init(&vkms_device->drm, 1); 202 if (ret) { 203 DRM_ERROR("Failed to vblank\n"); 204 goto out_devres; 205 } 206 207 ret = vkms_modeset_init(vkms_device); 208 if (ret) 209 goto out_devres; 210 211 drm_debugfs_add_files(&vkms_device->drm, vkms_config_debugfs_list, 212 ARRAY_SIZE(vkms_config_debugfs_list)); 213 214 ret = drm_dev_register(&vkms_device->drm, 0); 215 if (ret) 216 goto out_devres; 217 218 drm_client_setup(&vkms_device->drm, NULL); 219 220 return 0; 221 222 out_devres: 223 devres_release_group(&pdev->dev, NULL); 224 out_unregister: 225 platform_device_unregister(pdev); 226 return ret; 227 } 228 229 static int __init vkms_init(void) 230 { 231 int ret; 232 struct vkms_config *config; 233 234 config = kmalloc(sizeof(*config), GFP_KERNEL); 235 if (!config) 236 return -ENOMEM; 237 238 config->cursor = enable_cursor; 239 config->writeback = enable_writeback; 240 config->overlay = enable_overlay; 241 242 ret = vkms_create(config); 243 if (ret) { 244 kfree(config); 245 return ret; 246 } 247 248 default_config = config; 249 250 return 0; 251 } 252 253 static void vkms_destroy(struct vkms_config *config) 254 { 255 struct platform_device *pdev; 256 257 if (!config->dev) { 258 DRM_INFO("vkms_device is NULL.\n"); 259 return; 260 } 261 262 pdev = config->dev->platform; 263 264 drm_dev_unregister(&config->dev->drm); 265 drm_atomic_helper_shutdown(&config->dev->drm); 266 devres_release_group(&pdev->dev, NULL); 267 platform_device_unregister(pdev); 268 269 config->dev = NULL; 270 } 271 272 static void __exit vkms_exit(void) 273 { 274 if (!default_config) 275 return; 276 277 vkms_destroy(default_config); 278 kfree(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