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_fbdev_generic.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         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 =
  85                         to_vkms_crtc_state(old_crtc_state);
  86
  87                 flush_work(&vkms_state->composer_work);
  88         }
  89
  90         drm_atomic_helper_cleanup_planes(dev, old_state);
  91 }
  92
  93 static int vkms_config_show(struct seq_file *m, void *data)
  94 {
  95         struct drm_debugfs_entry *entry = m->private;
  96         struct drm_device *dev = entry->dev;
  97         struct vkms_device *vkmsdev = drm_device_to_vkms_device(dev);
  98
  99         seq_printf(m, "writeback=%d\n", vkmsdev->config->writeback);
 100         seq_printf(m, "cursor=%d\n", vkmsdev->config->cursor);
 101         seq_printf(m, "overlay=%d\n", vkmsdev->config->overlay);
 102
 103         return 0;
 104 }
 105
 106 static const struct drm_debugfs_info vkms_config_debugfs_list[] = {
 107         { "vkms_config", vkms_config_show, 0 },
 108 };
 109
 110 static const struct drm_driver vkms_driver = {
 111         .driver_features        = DRIVER_MODESET | DRIVER_ATOMIC | DRIVER_GEM,
 112         .release                = vkms_release,
 113         .fops                   = &vkms_driver_fops,
 114         DRM_GEM_SHMEM_DRIVER_OPS,
 115
 116         .name                   = DRIVER_NAME,
 117         .desc                   = DRIVER_DESC,
 118         .date                   = DRIVER_DATE,
 119         .major                  = DRIVER_MAJOR,
 120         .minor                  = DRIVER_MINOR,
 121 };
 122
 123 static int vkms_atomic_check(struct drm_device *dev, struct drm_atomic_state *state)
 124 {
 125         struct drm_crtc *crtc;
 126         struct drm_crtc_state *new_crtc_state;
 127         int i;
 128
 129         for_each_new_crtc_in_state(state, crtc, new_crtc_state, i) {
 130                 if (!new_crtc_state->gamma_lut || !new_crtc_state->color_mgmt_changed)
 131                         continue;
 132
 133                 if (new_crtc_state->gamma_lut->length / sizeof(struct drm_color_lut *)
 134                     > VKMS_LUT_SIZE)
 135                         return -EINVAL;
 136         }
 137
 138         return drm_atomic_helper_check(dev, state);
 139 }
 140
 141 static const struct drm_mode_config_funcs vkms_mode_funcs = {
 142         .fb_create = drm_gem_fb_create,
 143         .atomic_check = vkms_atomic_check,
 144         .atomic_commit = drm_atomic_helper_commit,
 145 };
 146
 147 static const struct drm_mode_config_helper_funcs vkms_mode_config_helpers = {
 148         .atomic_commit_tail = vkms_atomic_commit_tail,
 149 };
 150
 151 static int vkms_modeset_init(struct vkms_device *vkmsdev)
 152 {
 153         struct drm_device *dev = &vkmsdev->drm;
 154         int ret;
 155
 156         ret = drmm_mode_config_init(dev);
 157         if (ret)
 158                 return ret;
 159
 160         dev->mode_config.funcs = &vkms_mode_funcs;
 161         dev->mode_config.min_width = XRES_MIN;
 162         dev->mode_config.min_height = YRES_MIN;
 163         dev->mode_config.max_width = XRES_MAX;
 164         dev->mode_config.max_height = YRES_MAX;
 165         dev->mode_config.cursor_width = 512;
 166         dev->mode_config.cursor_height = 512;
 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 ix XRGB8888 in all cases. */
 170         dev->mode_config.preferred_depth = 0;
 171         dev->mode_config.helper_private = &vkms_mode_config_helpers;
 172
 173         return vkms_output_init(vkmsdev, 0);
 174 }
 175
 176 static int vkms_create(struct vkms_config *config)
 177 {
 178         int ret;
 179         struct platform_device *pdev;
 180         struct vkms_device *vkms_device;
 181
 182         pdev = platform_device_register_simple(DRIVER_NAME, -1, NULL, 0);
 183         if (IS_ERR(pdev))
 184                 return PTR_ERR(pdev);
 185
 186         if (!devres_open_group(&pdev->dev, NULL, GFP_KERNEL)) {
 187                 ret = -ENOMEM;
 188                 goto out_unregister;
 189         }
 190
 191         vkms_device = devm_drm_dev_alloc(&pdev->dev, &vkms_driver,
 192                                          struct vkms_device, drm);
 193         if (IS_ERR(vkms_device)) {
 194                 ret = PTR_ERR(vkms_device);
 195                 goto out_devres;
 196         }
 197         vkms_device->platform = pdev;
 198         vkms_device->config = config;
 199         config->dev = vkms_device;
 200
 201         ret = dma_coerce_mask_and_coherent(vkms_device->drm.dev,
 202                                            DMA_BIT_MASK(64));
 203
 204         if (ret) {
 205                 DRM_ERROR("Could not initialize DMA support\n");
 206                 goto out_devres;
 207         }
 208
 209         ret = drm_vblank_init(&vkms_device->drm, 1);
 210         if (ret) {
 211                 DRM_ERROR("Failed to vblank\n");
 212                 goto out_devres;
 213         }
 214
 215         ret = vkms_modeset_init(vkms_device);
 216         if (ret)
 217                 goto out_devres;
 218
 219         drm_debugfs_add_files(&vkms_device->drm, vkms_config_debugfs_list,
 220                               ARRAY_SIZE(vkms_config_debugfs_list));
 221
 222         ret = drm_dev_register(&vkms_device->drm, 0);
 223         if (ret)
 224                 goto out_devres;
 225
 226         drm_fbdev_generic_setup(&vkms_device->drm, 0);
 227
 228         return 0;
 229
 230 out_devres:
 231         devres_release_group(&pdev->dev, NULL);
 232 out_unregister:
 233         platform_device_unregister(pdev);
 234         return ret;
 235 }
 236
 237 static int __init vkms_init(void)
 238 {
 239         int ret;
 240         struct vkms_config *config;
 241
 242         config = kmalloc(sizeof(*config), GFP_KERNEL);
 243         if (!config)
 244                 return -ENOMEM;
 245
 246         default_config = config;
 247
 248         config->cursor = enable_cursor;
 249         config->writeback = enable_writeback;
 250         config->overlay = enable_overlay;
 251
 252         ret = vkms_create(config);
 253         if (ret)
 254                 kfree(config);
 255
 256         return ret;
 257 }
 258
 259 static void vkms_destroy(struct vkms_config *config)
 260 {
 261         struct platform_device *pdev;
 262
 263         if (!config->dev) {
 264                 DRM_INFO("vkms_device is NULL.\n");
 265                 return;
 266         }
 267
 268         pdev = config->dev->platform;
 269
 270         drm_dev_unregister(&config->dev->drm);
 271         drm_atomic_helper_shutdown(&config->dev->drm);
 272         devres_release_group(&pdev->dev, NULL);
 273         platform_device_unregister(pdev);
 274
 275         config->dev = NULL;
 276 }
 277
 278 static void __exit vkms_exit(void)
 279 {
 280         if (default_config->dev)
 281                 vkms_destroy(default_config);
 282
 283         kfree(default_config);
 284 }
 285
 286 module_init(vkms_init);
 287 module_exit(vkms_exit);
 288
 289 MODULE_AUTHOR("Haneen Mohammed <[email protected]>");
 290 MODULE_AUTHOR("Rodrigo Siqueira <[email protected]>");
 291 MODULE_DESCRIPTION(DRIVER_DESC);
 292 MODULE_LICENSE("GPL");