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/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 #include <drm/drm_print.h>
  32 #include <drm/drm_debugfs.h>
  33
  34 #define DRIVER_NAME     "vkms"
  35 #define DRIVER_DESC     "Virtual Kernel Mode Setting"
  36 #define DRIVER_DATE     "20180514"
  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         destroy_workqueue(vkms->output.composer_workq);
  61 }
  62
  63 static void vkms_atomic_commit_tail(struct drm_atomic_state *old_state)
  64 {
  65         struct drm_device *dev = old_state->dev;
  66         struct drm_crtc *crtc;
  67         struct drm_crtc_state *old_crtc_state;
  68         int i;
  69
  70         drm_atomic_helper_commit_modeset_disables(dev, old_state);
  71
  72         drm_atomic_helper_commit_planes(dev, old_state, 0);
  73
  74         drm_atomic_helper_commit_modeset_enables(dev, old_state);
  75
  76         drm_atomic_helper_fake_vblank(old_state);
  77
  78         drm_atomic_helper_commit_hw_done(old_state);
  79
  80         drm_atomic_helper_wait_for_flip_done(dev, old_state);
  81
  82         for_each_old_crtc_in_state(old_state, crtc, old_crtc_state, i) {
  83                 struct vkms_crtc_state *vkms_state =
  84                         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_info_node *node = (struct drm_info_node *)m->private;
  95         struct drm_device *dev = node->minor->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_info_list vkms_config_debugfs_list[] = {
 106         { "vkms_config", vkms_config_show, 0 },
 107 };
 108
 109 static void vkms_config_debugfs_init(struct drm_minor *minor)
 110 {
 111         drm_debugfs_create_files(vkms_config_debugfs_list, ARRAY_SIZE(vkms_config_debugfs_list),
 112                                  minor->debugfs_root, minor);
 113 }
 114
 115 static const struct drm_driver vkms_driver = {
 116         .driver_features        = DRIVER_MODESET | DRIVER_ATOMIC | DRIVER_GEM,
 117         .release                = vkms_release,
 118         .fops                   = &vkms_driver_fops,
 119         DRM_GEM_SHMEM_DRIVER_OPS,
 120
 121         .debugfs_init           = vkms_config_debugfs_init,
 122
 123         .name                   = DRIVER_NAME,
 124         .desc                   = DRIVER_DESC,
 125         .date                   = DRIVER_DATE,
 126         .major                  = DRIVER_MAJOR,
 127         .minor                  = DRIVER_MINOR,
 128 };
 129
 130 static const struct drm_mode_config_funcs vkms_mode_funcs = {
 131         .fb_create = drm_gem_fb_create,
 132         .atomic_check = drm_atomic_helper_check,
 133         .atomic_commit = drm_atomic_helper_commit,
 134 };
 135
 136 static const struct drm_mode_config_helper_funcs vkms_mode_config_helpers = {
 137         .atomic_commit_tail = vkms_atomic_commit_tail,
 138 };
 139
 140 static int vkms_modeset_init(struct vkms_device *vkmsdev)
 141 {
 142         struct drm_device *dev = &vkmsdev->drm;
 143
 144         drm_mode_config_init(dev);
 145         dev->mode_config.funcs = &vkms_mode_funcs;
 146         dev->mode_config.min_width = XRES_MIN;
 147         dev->mode_config.min_height = YRES_MIN;
 148         dev->mode_config.max_width = XRES_MAX;
 149         dev->mode_config.max_height = YRES_MAX;
 150         dev->mode_config.cursor_width = 512;
 151         dev->mode_config.cursor_height = 512;
 152         /* FIXME: There's a confusion between bpp and depth between this and
 153          * fbdev helpers. We have to go with 0, meaning "pick the default",
 154          * which ix XRGB8888 in all cases. */
 155         dev->mode_config.preferred_depth = 0;
 156         dev->mode_config.helper_private = &vkms_mode_config_helpers;
 157
 158         return vkms_output_init(vkmsdev, 0);
 159 }
 160
 161 static int vkms_create(struct vkms_config *config)
 162 {
 163         int ret;
 164         struct platform_device *pdev;
 165         struct vkms_device *vkms_device;
 166
 167         pdev = platform_device_register_simple(DRIVER_NAME, -1, NULL, 0);
 168         if (IS_ERR(pdev))
 169                 return PTR_ERR(pdev);
 170
 171         if (!devres_open_group(&pdev->dev, NULL, GFP_KERNEL)) {
 172                 ret = -ENOMEM;
 173                 goto out_unregister;
 174         }
 175
 176         vkms_device = devm_drm_dev_alloc(&pdev->dev, &vkms_driver,
 177                                          struct vkms_device, drm);
 178         if (IS_ERR(vkms_device)) {
 179                 ret = PTR_ERR(vkms_device);
 180                 goto out_devres;
 181         }
 182         vkms_device->platform = pdev;
 183         vkms_device->config = config;
 184         config->dev = vkms_device;
 185
 186         ret = dma_coerce_mask_and_coherent(vkms_device->drm.dev,
 187                                            DMA_BIT_MASK(64));
 188
 189         if (ret) {
 190                 DRM_ERROR("Could not initialize DMA support\n");
 191                 goto out_devres;
 192         }
 193
 194         ret = drm_vblank_init(&vkms_device->drm, 1);
 195         if (ret) {
 196                 DRM_ERROR("Failed to vblank\n");
 197                 goto out_devres;
 198         }
 199
 200         ret = vkms_modeset_init(vkms_device);
 201         if (ret)
 202                 goto out_devres;
 203
 204         ret = drm_dev_register(&vkms_device->drm, 0);
 205         if (ret)
 206                 goto out_devres;
 207
 208         drm_fbdev_generic_setup(&vkms_device->drm, 0);
 209
 210         return 0;
 211
 212 out_devres:
 213         devres_release_group(&pdev->dev, NULL);
 214 out_unregister:
 215         platform_device_unregister(pdev);
 216         return ret;
 217 }
 218
 219 static int __init vkms_init(void)
 220 {
 221         struct vkms_config *config;
 222
 223         config = kmalloc(sizeof(*config), GFP_KERNEL);
 224         if (!config)
 225                 return -ENOMEM;
 226
 227         default_config = config;
 228
 229         config->cursor = enable_cursor;
 230         config->writeback = enable_writeback;
 231         config->overlay = enable_overlay;
 232
 233         return vkms_create(config);
 234 }
 235
 236 static void vkms_destroy(struct vkms_config *config)
 237 {
 238         struct platform_device *pdev;
 239
 240         if (!config->dev) {
 241                 DRM_INFO("vkms_device is NULL.\n");
 242                 return;
 243         }
 244
 245         pdev = config->dev->platform;
 246
 247         drm_dev_unregister(&config->dev->drm);
 248         drm_atomic_helper_shutdown(&config->dev->drm);
 249         devres_release_group(&pdev->dev, NULL);
 250         platform_device_unregister(pdev);
 251
 252         config->dev = NULL;
 253 }
 254
 255 static void __exit vkms_exit(void)
 256 {
 257         if (default_config->dev)
 258                 vkms_destroy(default_config);
 259
 260         kfree(default_config);
 261 }
 262
 263 module_init(vkms_init);
 264 module_exit(vkms_exit);
 265
 266 MODULE_AUTHOR("Haneen Mohammed <[email protected]>");
 267 MODULE_AUTHOR("Rodrigo Siqueira <[email protected]>");
 268 MODULE_DESCRIPTION(DRIVER_DESC);
 269 MODULE_LICENSE("GPL");