drivers/gpu/drm/vkms/vkms_drv.c

   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_release(struct drm_device *dev)
  57 {
  58         struct vkms_device *vkms = drm_device_to_vkms_device(dev);
  59
  60         if (vkms->output.composer_workq)
  61                 destroy_workqueue(vkms->output.composer_workq);
  62 }
  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 int vkms_config_show(struct seq_file *m, void *data)
  93 {
  94         struct drm_debugfs_entry *entry = m->private;
  95         struct drm_device *dev = entry->dev;
  96         struct vkms_device *vkmsdev = drm_device_to_vkms_device(dev);
  97
  98         seq_printf(m, "writeback=%d\n", vkmsdev->config->writeback);
  99         seq_printf(m, "cursor=%d\n", vkmsdev->config->cursor);
 100         seq_printf(m, "overlay=%d\n", vkmsdev->config->overlay);
 101
 102         return 0;
 103 }
 104
 105 static const struct drm_debugfs_info vkms_config_debugfs_list[] = {
 106         { "vkms_config", vkms_config_show, 0 },
 107 };
 108
 109 static const struct drm_driver vkms_driver = {
 110         .driver_features        = DRIVER_MODESET | DRIVER_ATOMIC | DRIVER_GEM,
 111         .release                = vkms_release,
 112         .fops                   = &vkms_driver_fops,
 113         DRM_GEM_SHMEM_DRIVER_OPS,
 114         DRM_FBDEV_SHMEM_DRIVER_OPS,
 115
 116         .name                   = DRIVER_NAME,
 117         .desc                   = DRIVER_DESC,
 118         .major                  = DRIVER_MAJOR,
 119         .minor                  = DRIVER_MINOR,
 120 };
 121
 122 static int vkms_atomic_check(struct drm_device *dev, struct drm_atomic_state *state)
 123 {
 124         struct drm_crtc *crtc;
 125         struct drm_crtc_state *new_crtc_state;
 126         int i;
 127
 128         for_each_new_crtc_in_state(state, crtc, new_crtc_state, i) {
 129                 if (!new_crtc_state->gamma_lut || !new_crtc_state->color_mgmt_changed)
 130                         continue;
 131
 132                 if (new_crtc_state->gamma_lut->length / sizeof(struct drm_color_lut *)
 133                     > VKMS_LUT_SIZE)
 134                         return -EINVAL;
 135         }
 136
 137         return drm_atomic_helper_check(dev, state);
 138 }
 139
 140 static const struct drm_mode_config_funcs vkms_mode_funcs = {
 141         .fb_create = drm_gem_fb_create,
 142         .atomic_check = vkms_atomic_check,
 143         .atomic_commit = drm_atomic_helper_commit,
 144 };
 145
 146 static const struct drm_mode_config_helper_funcs vkms_mode_config_helpers = {
 147         .atomic_commit_tail = vkms_atomic_commit_tail,
 148 };
 149
 150 static int vkms_modeset_init(struct vkms_device *vkmsdev)
 151 {
 152         struct drm_device *dev = &vkmsdev->drm;
 153         int ret;
 154
 155         ret = drmm_mode_config_init(dev);
 156         if (ret)
 157                 return ret;
 158
 159         dev->mode_config.funcs = &vkms_mode_funcs;
 160         dev->mode_config.min_width = XRES_MIN;
 161         dev->mode_config.min_height = YRES_MIN;
 162         dev->mode_config.max_width = XRES_MAX;
 163         dev->mode_config.max_height = YRES_MAX;
 164         dev->mode_config.cursor_width = 512;
 165         dev->mode_config.cursor_height = 512;
 166         /*
 167          * FIXME: There's a confusion between bpp and depth between this and
 168          * fbdev helpers. We have to go with 0, meaning "pick the default",
 169          * which is XRGB8888 in all cases.
 170          */
 171         dev->mode_config.preferred_depth = 0;
 172         dev->mode_config.helper_private = &vkms_mode_config_helpers;
 173
 174         return vkms_output_init(vkmsdev);
 175 }
 176
 177 static int vkms_create(struct vkms_config *config)
 178 {
 179         int ret;
 180         struct platform_device *pdev;
 181         struct vkms_device *vkms_device;
 182
 183         pdev = platform_device_register_simple(DRIVER_NAME, -1, NULL, 0);
 184         if (IS_ERR(pdev))
 185                 return PTR_ERR(pdev);
 186
 187         if (!devres_open_group(&pdev->dev, NULL, GFP_KERNEL)) {
 188                 ret = -ENOMEM;
 189                 goto out_unregister;
 190         }
 191
 192         vkms_device = devm_drm_dev_alloc(&pdev->dev, &vkms_driver,
 193                                          struct vkms_device, drm);
 194         if (IS_ERR(vkms_device)) {
 195                 ret = PTR_ERR(vkms_device);
 196                 goto out_devres;
 197         }
 198         vkms_device->platform = pdev;
 199         vkms_device->config = config;
 200         config->dev = vkms_device;
 201
 202         ret = dma_coerce_mask_and_coherent(vkms_device->drm.dev,
 203                                            DMA_BIT_MASK(64));
 204
 205         if (ret) {
 206                 DRM_ERROR("Could not initialize DMA support\n");
 207                 goto out_devres;
 208         }
 209
 210         ret = drm_vblank_init(&vkms_device->drm, 1);
 211         if (ret) {
 212                 DRM_ERROR("Failed to vblank\n");
 213                 goto out_devres;
 214         }
 215
 216         ret = vkms_modeset_init(vkms_device);
 217         if (ret)
 218                 goto out_devres;
 219
 220         drm_debugfs_add_files(&vkms_device->drm, vkms_config_debugfs_list,
 221                               ARRAY_SIZE(vkms_config_debugfs_list));
 222
 223         ret = drm_dev_register(&vkms_device->drm, 0);
 224         if (ret)
 225                 goto out_devres;
 226
 227         drm_client_setup(&vkms_device->drm, NULL);
 228
 229         return 0;
 230
 231 out_devres:
 232         devres_release_group(&pdev->dev, NULL);
 233 out_unregister:
 234         platform_device_unregister(pdev);
 235         return ret;
 236 }
 237
 238 static int __init vkms_init(void)
 239 {
 240         int ret;
 241         struct vkms_config *config;
 242
 243         config = kmalloc(sizeof(*config), GFP_KERNEL);
 244         if (!config)
 245                 return -ENOMEM;
 246
 247         default_config = config;
 248
 249         config->cursor = enable_cursor;
 250         config->writeback = enable_writeback;
 251         config->overlay = enable_overlay;
 252
 253         ret = vkms_create(config);
 254         if (ret)
 255                 kfree(config);
 256
 257         return ret;
 258 }
 259
 260 static void vkms_destroy(struct vkms_config *config)
 261 {
 262         struct platform_device *pdev;
 263
 264         if (!config->dev) {
 265                 DRM_INFO("vkms_device is NULL.\n");
 266                 return;
 267         }
 268
 269         pdev = config->dev->platform;
 270
 271         drm_dev_unregister(&config->dev->drm);
 272         drm_atomic_helper_shutdown(&config->dev->drm);
 273         devres_release_group(&pdev->dev, NULL);
 274         platform_device_unregister(pdev);
 275
 276         config->dev = NULL;
 277 }
 278
 279 static void __exit vkms_exit(void)
 280 {
 281         if (default_config->dev)
 282                 vkms_destroy(default_config);
 283
 284         kfree(default_config);
 285 }
 286
 287 module_init(vkms_init);
 288 module_exit(vkms_exit);
 289
 290 MODULE_AUTHOR("Haneen Mohammed <[email protected]>");
 291 MODULE_AUTHOR("Rodrigo Siqueira <[email protected]>");
 292 MODULE_DESCRIPTION(DRIVER_DESC);
 293 MODULE_LICENSE("GPL");