drivers/virtio/virtio-uclass.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * Copyright (C) 2018, Tuomas Tynkkynen <tuomas.tynkkynen@iki.fi>
   4  * Copyright (C) 2018, Bin Meng <bmeng.cn@gmail.com>
   5  *
   6  * VirtIO is a virtualization standard for network and disk device drivers
   7  * where just the guest's device driver "knows" it is running in a virtual
   8  * environment, and cooperates with the hypervisor. This enables guests to
   9  * get high performance network and disk operations, and gives most of the
  10  * performance benefits of paravirtualization. In the U-Boot case, the guest
  11  * is U-Boot itself, while the virtual environment are normally QEMU targets
  12  * like ARM, RISC-V and x86.
  13  *
  14  * See http://docs.oasis-open.org/virtio/virtio/v1.0/virtio-v1.0.pdf for
  15  * the VirtIO specification v1.0.
  16  */
  17
  18 #include <common.h>
  19 #include <dm.h>
  20 #include <malloc.h>
  21 #include <virtio_types.h>
  22 #include <virtio.h>
  23 #include <dm/lists.h>
  24
  25 static const char *const virtio_drv_name[VIRTIO_ID_MAX_NUM] = {
  26         [VIRTIO_ID_NET]         = VIRTIO_NET_DRV_NAME,
  27         [VIRTIO_ID_BLOCK]       = VIRTIO_BLK_DRV_NAME,
  28         [VIRTIO_ID_RNG]         = VIRTIO_RNG_DRV_NAME,
  29 };
  30
  31 int virtio_get_config(struct udevice *vdev, unsigned int offset,
  32                       void *buf, unsigned int len)
  33 {
  34         struct dm_virtio_ops *ops;
  35
  36         ops = virtio_get_ops(vdev->parent);
  37
  38         return ops->get_config(vdev->parent, offset, buf, len);
  39 }
  40
  41 int virtio_set_config(struct udevice *vdev, unsigned int offset,
  42                       void *buf, unsigned int len)
  43 {
  44         struct dm_virtio_ops *ops;
  45
  46         ops = virtio_get_ops(vdev->parent);
  47
  48         return ops->set_config(vdev->parent, offset, buf, len);
  49 }
  50
  51 int virtio_generation(struct udevice *vdev, u32 *counter)
  52 {
  53         struct dm_virtio_ops *ops;
  54
  55         ops = virtio_get_ops(vdev->parent);
  56         if (!ops->generation)
  57                 return -ENOSYS;
  58
  59         return ops->generation(vdev->parent, counter);
  60 }
  61
  62 int virtio_get_status(struct udevice *vdev, u8 *status)
  63 {
  64         struct dm_virtio_ops *ops;
  65
  66         ops = virtio_get_ops(vdev->parent);
  67
  68         return ops->get_status(vdev->parent, status);
  69 }
  70
  71 int virtio_set_status(struct udevice *vdev, u8 status)
  72 {
  73         struct dm_virtio_ops *ops;
  74
  75         ops = virtio_get_ops(vdev->parent);
  76
  77         return ops->set_status(vdev->parent, status);
  78 }
  79
  80 int virtio_reset(struct udevice *vdev)
  81 {
  82         struct dm_virtio_ops *ops;
  83
  84         ops = virtio_get_ops(vdev->parent);
  85
  86         return ops->reset(vdev->parent);
  87 }
  88
  89 int virtio_get_features(struct udevice *vdev, u64 *features)
  90 {
  91         struct dm_virtio_ops *ops;
  92
  93         ops = virtio_get_ops(vdev->parent);
  94
  95         return ops->get_features(vdev->parent, features);
  96 }
  97
  98 int virtio_set_features(struct udevice *vdev)
  99 {
 100         struct dm_virtio_ops *ops;
 101
 102         ops = virtio_get_ops(vdev->parent);
 103
 104         return ops->set_features(vdev->parent);
 105 }
 106
 107 int virtio_find_vqs(struct udevice *vdev, unsigned int nvqs,
 108                     struct virtqueue *vqs[])
 109 {
 110         struct dm_virtio_ops *ops;
 111
 112         ops = virtio_get_ops(vdev->parent);
 113
 114         return ops->find_vqs(vdev->parent, nvqs, vqs);
 115 }
 116
 117 int virtio_del_vqs(struct udevice *vdev)
 118 {
 119         struct dm_virtio_ops *ops;
 120
 121         ops = virtio_get_ops(vdev->parent);
 122
 123         return ops->del_vqs(vdev->parent);
 124 }
 125
 126 int virtio_notify(struct udevice *vdev, struct virtqueue *vq)
 127 {
 128         struct dm_virtio_ops *ops;
 129
 130         ops = virtio_get_ops(vdev->parent);
 131
 132         return ops->notify(vdev->parent, vq);
 133 }
 134
 135 void virtio_add_status(struct udevice *vdev, u8 status)
 136 {
 137         u8 old;
 138
 139         if (!virtio_get_status(vdev, &old))
 140                 virtio_set_status(vdev, old | status);
 141 }
 142
 143 int virtio_finalize_features(struct udevice *vdev)
 144 {
 145         struct virtio_dev_priv *uc_priv = dev_get_uclass_priv(vdev->parent);
 146         u8 status;
 147         int ret;
 148
 149         ret = virtio_set_features(vdev);
 150         if (ret)
 151                 return ret;
 152
 153         if (uc_priv->legacy)
 154                 return 0;
 155
 156         virtio_add_status(vdev, VIRTIO_CONFIG_S_FEATURES_OK);
 157         ret = virtio_get_status(vdev, &status);
 158         if (ret)
 159                 return ret;
 160         if (!(status & VIRTIO_CONFIG_S_FEATURES_OK)) {
 161                 debug("(%s): device refuses features %x\n", vdev->name, status);
 162                 return -ENODEV;
 163         }
 164
 165         return 0;
 166 }
 167
 168 void virtio_driver_features_init(struct virtio_dev_priv *priv,
 169                                  const u32 *feature,
 170                                  u32 feature_size,
 171                                  const u32 *feature_legacy,
 172                                  u32 feature_legacy_size)
 173 {
 174         priv->feature_table = feature;
 175         priv->feature_table_size = feature_size;
 176         priv->feature_table_legacy = feature_legacy;
 177         priv->feature_table_size_legacy = feature_legacy_size;
 178 }
 179
 180 int virtio_init(void)
 181 {
 182         struct udevice *bus;
 183         int ret;
 184
 185         /* Enumerate all known virtio devices */
 186         ret = uclass_first_device(UCLASS_VIRTIO, &bus);
 187         if (ret)
 188                 return ret;
 189
 190         while (bus) {
 191                 ret = uclass_next_device(&bus);
 192                 if (ret)
 193                         break;
 194         }
 195
 196         return ret;
 197 }
 198
 199 static int virtio_uclass_pre_probe(struct udevice *udev)
 200 {
 201         struct dm_virtio_ops *ops;
 202
 203         ops = (struct dm_virtio_ops *)(udev->driver->ops);
 204
 205         /*
 206          * Check virtio transport driver ops here so that we don't need
 207          * check these ops each time when the virtio_xxx APIs are called.
 208          *
 209          * Only generation op is optional. All other ops are must-have.
 210          */
 211         if (!ops->get_config || !ops->set_config ||
 212             !ops->get_status || !ops->set_status ||
 213             !ops->get_features || !ops->set_features ||
 214             !ops->find_vqs || !ops->del_vqs ||
 215             !ops->reset || !ops->notify)
 216                 return -ENOENT;
 217
 218         return 0;
 219 }
 220
 221 static int virtio_uclass_post_probe(struct udevice *udev)
 222 {
 223         struct virtio_dev_priv *uc_priv = dev_get_uclass_priv(udev);
 224         char dev_name[30], *str;
 225         struct udevice *vdev;
 226         int ret;
 227
 228         if (uc_priv->device > VIRTIO_ID_MAX_NUM) {
 229                 debug("(%s): virtio device ID %d exceeds maximum num\n",
 230                       udev->name, uc_priv->device);
 231                 return 0;
 232         }
 233
 234         if (!virtio_drv_name[uc_priv->device]) {
 235                 debug("(%s): underlying virtio device driver unavailable\n",
 236                       udev->name);
 237                 return 0;
 238         }
 239
 240         snprintf(dev_name, sizeof(dev_name), "%s#%d",
 241                  virtio_drv_name[uc_priv->device], udev->seq);
 242         str = strdup(dev_name);
 243         if (!str)
 244                 return -ENOMEM;
 245
 246         ret = device_bind_driver(udev, virtio_drv_name[uc_priv->device],
 247                                  str, &vdev);
 248         if (ret == -ENOENT) {
 249                 debug("(%s): no driver configured\n", udev->name);
 250                 return 0;
 251         }
 252         if (ret) {
 253                 free(str);
 254                 return ret;
 255         }
 256         device_set_name_alloced(vdev);
 257
 258         INIT_LIST_HEAD(&uc_priv->vqs);
 259
 260         return 0;
 261 }
 262
 263 static int virtio_uclass_child_post_bind(struct udevice *vdev)
 264 {
 265         /* Acknowledge that we've seen the device */
 266         virtio_add_status(vdev, VIRTIO_CONFIG_S_ACKNOWLEDGE);
 267
 268         return 0;
 269 }
 270
 271 static int virtio_uclass_child_pre_probe(struct udevice *vdev)
 272 {
 273         struct virtio_dev_priv *uc_priv = dev_get_uclass_priv(vdev->parent);
 274         u64 device_features;
 275         u64 driver_features;
 276         u64 driver_features_legacy;
 277         int i;
 278         int ret;
 279
 280         /*
 281          * Save the real virtio device (eg: virtio-net, virtio-blk) to
 282          * the transport (parent) device's uclass priv for future use.
 283          */
 284         uc_priv->vdev = vdev;
 285
 286         /*
 287          * We always start by resetting the device, in case a previous driver
 288          * messed it up. This also tests that code path a little.
 289          */
 290         ret = virtio_reset(vdev);
 291         if (ret)
 292                 goto err;
 293
 294         /* We have a driver! */
 295         virtio_add_status(vdev, VIRTIO_CONFIG_S_DRIVER);
 296
 297         /* Figure out what features the device supports */
 298         virtio_get_features(vdev, &device_features);
 299         debug("(%s) plain device features supported %016llx\n",
 300               vdev->name, device_features);
 301         if (!(device_features & (1ULL << VIRTIO_F_VERSION_1)))
 302                 uc_priv->legacy = true;
 303
 304         /* Figure out what features the driver supports */
 305         driver_features = 0;
 306         for (i = 0; i < uc_priv->feature_table_size; i++) {
 307                 unsigned int f = uc_priv->feature_table[i];
 308
 309                 WARN_ON(f >= 64);
 310                 driver_features |= (1ULL << f);
 311         }
 312
 313         /* Some drivers have a separate feature table for virtio v1.0 */
 314         if (uc_priv->feature_table_legacy) {
 315                 driver_features_legacy = 0;
 316                 for (i = 0; i < uc_priv->feature_table_size_legacy; i++) {
 317                         unsigned int f = uc_priv->feature_table_legacy[i];
 318
 319                         WARN_ON(f >= 64);
 320                         driver_features_legacy |= (1ULL << f);
 321                 }
 322         } else {
 323                 driver_features_legacy = driver_features;
 324         }
 325
 326         if (uc_priv->legacy) {
 327                 debug("(%s): legacy virtio device\n", vdev->name);
 328                 uc_priv->features = driver_features_legacy & device_features;
 329         } else {
 330                 debug("(%s): v1.0 complaint virtio device\n", vdev->name);
 331                 uc_priv->features = driver_features & device_features;
 332         }
 333
 334         /* Transport features always preserved to pass to finalize_features */
 335         for (i = VIRTIO_TRANSPORT_F_START; i < VIRTIO_TRANSPORT_F_END; i++)
 336                 if ((device_features & (1ULL << i)) &&
 337                     (i == VIRTIO_F_VERSION_1))
 338                         __virtio_set_bit(vdev->parent, i);
 339
 340         debug("(%s) final negotiated features supported %016llx\n",
 341               vdev->name, uc_priv->features);
 342         ret = virtio_finalize_features(vdev);
 343         if (ret)
 344                 goto err;
 345
 346         return 0;
 347
 348 err:
 349         virtio_add_status(vdev, VIRTIO_CONFIG_S_FAILED);
 350         return ret;
 351 }
 352
 353 static int virtio_uclass_child_post_probe(struct udevice *vdev)
 354 {
 355         /* Indicates that the driver is set up and ready to drive the device */
 356         virtio_add_status(vdev, VIRTIO_CONFIG_S_DRIVER_OK);
 357
 358         return 0;
 359 }
 360
 361 UCLASS_DRIVER(virtio) = {
 362         .name   = "virtio",
 363         .id     = UCLASS_VIRTIO,
 364         .flags  = DM_UC_FLAG_SEQ_ALIAS,
 365         .pre_probe = virtio_uclass_pre_probe,
 366         .post_probe = virtio_uclass_post_probe,
 367         .child_post_bind = virtio_uclass_child_post_bind,
 368         .child_pre_probe = virtio_uclass_child_pre_probe,
 369         .child_post_probe = virtio_uclass_child_post_probe,
 370         .per_device_auto_alloc_size = sizeof(struct virtio_dev_priv),
 371 };