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 #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");