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