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/drm_gem.h> 17 #include <drm/drm_atomic.h> 18 #include <drm/drm_atomic_helper.h> 19 #include <drm/drm_drv.h> 20 #include <drm/drm_fb_helper.h> 21 #include <drm/drm_file.h> 22 #include <drm/drm_gem_framebuffer_helper.h> 23 #include <drm/drm_ioctl.h> 24 #include <drm/drm_managed.h> 25 #include <drm/drm_probe_helper.h> 26 #include <drm/drm_gem_shmem_helper.h> 27 #include <drm/drm_vblank.h> 28 29 #include "vkms_drv.h" 30 31 #define DRIVER_NAME "vkms" 32 #define DRIVER_DESC "Virtual Kernel Mode Setting" 33 #define DRIVER_DATE "20180514" 34 #define DRIVER_MAJOR 1 35 #define DRIVER_MINOR 0 36 37 static struct vkms_config *default_config; 38 39 static bool enable_cursor = true; 40 module_param_named(enable_cursor, enable_cursor, bool, 0444); 41 MODULE_PARM_DESC(enable_cursor, "Enable/Disable cursor support"); 42 43 static bool enable_writeback = true; 44 module_param_named(enable_writeback, enable_writeback, bool, 0444); 45 MODULE_PARM_DESC(enable_writeback, "Enable/Disable writeback connector support"); 46 47 DEFINE_DRM_GEM_FOPS(vkms_driver_fops); 48 49 static void vkms_release(struct drm_device *dev) 50 { 51 struct vkms_device *vkms = container_of(dev, struct vkms_device, drm); 52 53 destroy_workqueue(vkms->output.composer_workq); 54 } 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 = 77 to_vkms_crtc_state(old_crtc_state); 78 79 flush_work(&vkms_state->composer_work); 80 } 81 82 drm_atomic_helper_cleanup_planes(dev, old_state); 83 } 84 85 static const struct drm_driver vkms_driver = { 86 .driver_features = DRIVER_MODESET | DRIVER_ATOMIC | DRIVER_GEM, 87 .release = vkms_release, 88 .fops = &vkms_driver_fops, 89 DRM_GEM_SHMEM_DRIVER_OPS, 90 91 .name = DRIVER_NAME, 92 .desc = DRIVER_DESC, 93 .date = DRIVER_DATE, 94 .major = DRIVER_MAJOR, 95 .minor = DRIVER_MINOR, 96 }; 97 98 static const struct drm_mode_config_funcs vkms_mode_funcs = { 99 .fb_create = drm_gem_fb_create, 100 .atomic_check = drm_atomic_helper_check, 101 .atomic_commit = drm_atomic_helper_commit, 102 }; 103 104 static const struct drm_mode_config_helper_funcs vkms_mode_config_helpers = { 105 .atomic_commit_tail = vkms_atomic_commit_tail, 106 }; 107 108 static int vkms_modeset_init(struct vkms_device *vkmsdev) 109 { 110 struct drm_device *dev = &vkmsdev->drm; 111 112 drm_mode_config_init(dev); 113 dev->mode_config.funcs = &vkms_mode_funcs; 114 dev->mode_config.min_width = XRES_MIN; 115 dev->mode_config.min_height = YRES_MIN; 116 dev->mode_config.max_width = XRES_MAX; 117 dev->mode_config.max_height = YRES_MAX; 118 dev->mode_config.cursor_width = 512; 119 dev->mode_config.cursor_height = 512; 120 /* FIXME: There's a confusion between bpp and depth between this and 121 * fbdev helpers. We have to go with 0, meaning "pick the default", 122 * which ix XRGB8888 in all cases. */ 123 dev->mode_config.preferred_depth = 0; 124 dev->mode_config.helper_private = &vkms_mode_config_helpers; 125 126 return vkms_output_init(vkmsdev, 0); 127 } 128 129 static int vkms_create(struct vkms_config *config) 130 { 131 int ret; 132 struct platform_device *pdev; 133 struct vkms_device *vkms_device; 134 135 pdev = platform_device_register_simple(DRIVER_NAME, -1, NULL, 0); 136 if (IS_ERR(pdev)) 137 return PTR_ERR(pdev); 138 139 if (!devres_open_group(&pdev->dev, NULL, GFP_KERNEL)) { 140 ret = -ENOMEM; 141 goto out_unregister; 142 } 143 144 vkms_device = devm_drm_dev_alloc(&pdev->dev, &vkms_driver, 145 struct vkms_device, drm); 146 if (IS_ERR(vkms_device)) { 147 ret = PTR_ERR(vkms_device); 148 goto out_devres; 149 } 150 vkms_device->platform = pdev; 151 vkms_device->config = config; 152 config->dev = vkms_device; 153 154 ret = dma_coerce_mask_and_coherent(vkms_device->drm.dev, 155 DMA_BIT_MASK(64)); 156 157 if (ret) { 158 DRM_ERROR("Could not initialize DMA support\n"); 159 goto out_devres; 160 } 161 162 vkms_device->drm.irq_enabled = true; 163 164 ret = drm_vblank_init(&vkms_device->drm, 1); 165 if (ret) { 166 DRM_ERROR("Failed to vblank\n"); 167 goto out_devres; 168 } 169 170 ret = vkms_modeset_init(vkms_device); 171 if (ret) 172 goto out_devres; 173 174 ret = drm_dev_register(&vkms_device->drm, 0); 175 if (ret) 176 goto out_devres; 177 178 drm_fbdev_generic_setup(&vkms_device->drm, 0); 179 180 return 0; 181 182 out_devres: 183 devres_release_group(&pdev->dev, NULL); 184 out_unregister: 185 platform_device_unregister(pdev); 186 return ret; 187 } 188 189 static int __init vkms_init(void) 190 { 191 struct vkms_config *config; 192 193 config = kmalloc(sizeof(*config), GFP_KERNEL); 194 if (!config) 195 return -ENOMEM; 196 197 default_config = config; 198 199 config->cursor = enable_cursor; 200 config->writeback = enable_writeback; 201 202 return vkms_create(config); 203 } 204 205 static void vkms_destroy(struct vkms_config *config) 206 { 207 struct platform_device *pdev; 208 209 if (!config->dev) { 210 DRM_INFO("vkms_device is NULL.\n"); 211 return; 212 } 213 214 pdev = config->dev->platform; 215 216 drm_dev_unregister(&config->dev->drm); 217 drm_atomic_helper_shutdown(&config->dev->drm); 218 devres_release_group(&pdev->dev, NULL); 219 platform_device_unregister(pdev); 220 221 config->dev = NULL; 222 } 223 224 static void __exit vkms_exit(void) 225 { 226 if (default_config->dev) 227 vkms_destroy(default_config); 228 229 kfree(default_config); 230 } 231 232 module_init(vkms_init); 233 module_exit(vkms_exit); 234 235 MODULE_AUTHOR("Haneen Mohammed <hamohammed.sa@gmail.com>"); 236 MODULE_AUTHOR("Rodrigo Siqueira <rodrigosiqueiramelo@gmail.com>"); 237 MODULE_DESCRIPTION(DRIVER_DESC); 238 MODULE_LICENSE("GPL"); 239