drivers/remoteproc/remoteproc_virtio.c

   1 /*
   2  * Remote processor messaging transport (OMAP platform-specific bits)
   3  *
   4  * Copyright (C) 2011 Texas Instruments, Inc.
   5  * Copyright (C) 2011 Google, Inc.
   6  *
   7  * Ohad Ben-Cohen <ohad@wizery.com>
   8  * Brian Swetland <swetland@google.com>
   9  *
  10  * This software is licensed under the terms of the GNU General Public
  11  * License version 2, as published by the Free Software Foundation, and
  12  * may be copied, distributed, and modified under those terms.
  13  *
  14  * This program is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17  * GNU General Public License for more details.
  18  */
  19
  20 #include <linux/export.h>
  21 #include <linux/remoteproc.h>
  22 #include <linux/virtio.h>
  23 #include <linux/virtio_config.h>
  24 #include <linux/virtio_ids.h>
  25 #include <linux/virtio_ring.h>
  26 #include <linux/err.h>
  27 #include <linux/kref.h>
  28 #include <linux/slab.h>
  29
  30 #include "remoteproc_internal.h"
  31
  32 /* kick the remote processor, and let it know which virtqueue to poke at */
  33 static bool rproc_virtio_notify(struct virtqueue *vq)
  34 {
  35         struct rproc_vring *rvring = vq->priv;
  36         struct rproc *rproc = rvring->rvdev->rproc;
  37         int notifyid = rvring->notifyid;
  38
  39         dev_dbg(&rproc->dev, "kicking vq index: %d\n", notifyid);
  40
  41         rproc->ops->kick(rproc, notifyid);
  42         return true;
  43 }
  44
  45 /**
  46  * rproc_vq_interrupt() - tell remoteproc that a virtqueue is interrupted
  47  * @rproc: handle to the remote processor
  48  * @notifyid: index of the signalled virtqueue (unique per this @rproc)
  49  *
  50  * This function should be called by the platform-specific rproc driver,
  51  * when the remote processor signals that a specific virtqueue has pending
  52  * messages available.
  53  *
  54  * Returns IRQ_NONE if no message was found in the @notifyid virtqueue,
  55  * and otherwise returns IRQ_HANDLED.
  56  */
  57 irqreturn_t rproc_vq_interrupt(struct rproc *rproc, int notifyid)
  58 {
  59         struct rproc_vring *rvring;
  60
  61         dev_dbg(&rproc->dev, "vq index %d is interrupted\n", notifyid);
  62
  63         rvring = idr_find(&rproc->notifyids, notifyid);
  64         if (!rvring || !rvring->vq)
  65                 return IRQ_NONE;
  66
  67         return vring_interrupt(0, rvring->vq);
  68 }
  69 EXPORT_SYMBOL(rproc_vq_interrupt);
  70
  71 static struct virtqueue *rp_find_vq(struct virtio_device *vdev,
  72                                     unsigned int id,
  73                                     void (*callback)(struct virtqueue *vq),
  74                                     const char *name)
  75 {
  76         struct rproc_vdev *rvdev = vdev_to_rvdev(vdev);
  77         struct rproc *rproc = vdev_to_rproc(vdev);
  78         struct device *dev = &rproc->dev;
  79         struct rproc_vring *rvring;
  80         struct virtqueue *vq;
  81         void *addr;
  82         int len, size, ret;
  83
  84         /* we're temporarily limited to two virtqueues per rvdev */
  85         if (id >= ARRAY_SIZE(rvdev->vring))
  86                 return ERR_PTR(-EINVAL);
  87
  88         if (!name)
  89                 return NULL;
  90
  91         ret = rproc_alloc_vring(rvdev, id);
  92         if (ret)
  93                 return ERR_PTR(ret);
  94
  95         rvring = &rvdev->vring[id];
  96         addr = rvring->va;
  97         len = rvring->len;
  98
  99         /* zero vring */
 100         size = vring_size(len, rvring->align);
 101         memset(addr, 0, size);
 102
 103         dev_dbg(dev, "vring%d: va %p qsz %d notifyid %d\n",
 104                 id, addr, len, rvring->notifyid);
 105
 106         /*
 107          * Create the new vq, and tell virtio we're not interested in
 108          * the 'weak' smp barriers, since we're talking with a real device.
 109          */
 110         vq = vring_new_virtqueue(id, len, rvring->align, vdev, false, addr,
 111                                  rproc_virtio_notify, callback, name);
 112         if (!vq) {
 113                 dev_err(dev, "vring_new_virtqueue %s failed\n", name);
 114                 rproc_free_vring(rvring);
 115                 return ERR_PTR(-ENOMEM);
 116         }
 117
 118         rvring->vq = vq;
 119         vq->priv = rvring;
 120
 121         return vq;
 122 }
 123
 124 static void __rproc_virtio_del_vqs(struct virtio_device *vdev)
 125 {
 126         struct virtqueue *vq, *n;
 127         struct rproc_vring *rvring;
 128
 129         list_for_each_entry_safe(vq, n, &vdev->vqs, list) {
 130                 rvring = vq->priv;
 131                 rvring->vq = NULL;
 132                 vring_del_virtqueue(vq);
 133                 rproc_free_vring(rvring);
 134         }
 135 }
 136
 137 static void rproc_virtio_del_vqs(struct virtio_device *vdev)
 138 {
 139         __rproc_virtio_del_vqs(vdev);
 140 }
 141
 142 static int rproc_virtio_find_vqs(struct virtio_device *vdev, unsigned int nvqs,
 143                                  struct virtqueue *vqs[],
 144                                  vq_callback_t *callbacks[],
 145                                  const char * const names[])
 146 {
 147         int i, ret;
 148
 149         for (i = 0; i < nvqs; ++i) {
 150                 vqs[i] = rp_find_vq(vdev, i, callbacks[i], names[i]);
 151                 if (IS_ERR(vqs[i])) {
 152                         ret = PTR_ERR(vqs[i]);
 153                         goto error;
 154                 }
 155         }
 156
 157         return 0;
 158
 159 error:
 160         __rproc_virtio_del_vqs(vdev);
 161         return ret;
 162 }
 163
 164 static u8 rproc_virtio_get_status(struct virtio_device *vdev)
 165 {
 166         struct rproc_vdev *rvdev = vdev_to_rvdev(vdev);
 167         struct fw_rsc_vdev *rsc;
 168
 169         rsc = (void *)rvdev->rproc->table_ptr + rvdev->rsc_offset;
 170
 171         return rsc->status;
 172 }
 173
 174 static void rproc_virtio_set_status(struct virtio_device *vdev, u8 status)
 175 {
 176         struct rproc_vdev *rvdev = vdev_to_rvdev(vdev);
 177         struct fw_rsc_vdev *rsc;
 178
 179         rsc = (void *)rvdev->rproc->table_ptr + rvdev->rsc_offset;
 180
 181         rsc->status = status;
 182         dev_dbg(&vdev->dev, "status: %d\n", status);
 183 }
 184
 185 static void rproc_virtio_reset(struct virtio_device *vdev)
 186 {
 187         struct rproc_vdev *rvdev = vdev_to_rvdev(vdev);
 188         struct fw_rsc_vdev *rsc;
 189
 190         rsc = (void *)rvdev->rproc->table_ptr + rvdev->rsc_offset;
 191
 192         rsc->status = 0;
 193         dev_dbg(&vdev->dev, "reset !\n");
 194 }
 195
 196 /* provide the vdev features as retrieved from the firmware */
 197 static u64 rproc_virtio_get_features(struct virtio_device *vdev)
 198 {
 199         struct rproc_vdev *rvdev = vdev_to_rvdev(vdev);
 200         struct fw_rsc_vdev *rsc;
 201
 202         rsc = (void *)rvdev->rproc->table_ptr + rvdev->rsc_offset;
 203
 204         return rsc->dfeatures;
 205 }
 206
 207 static int rproc_virtio_finalize_features(struct virtio_device *vdev)
 208 {
 209         struct rproc_vdev *rvdev = vdev_to_rvdev(vdev);
 210         struct fw_rsc_vdev *rsc;
 211
 212         rsc = (void *)rvdev->rproc->table_ptr + rvdev->rsc_offset;
 213
 214         /* Give virtio_ring a chance to accept features */
 215         vring_transport_features(vdev);
 216
 217         /* Make sure we don't have any features > 32 bits! */
 218         BUG_ON((u32)vdev->features != vdev->features);
 219
 220         /*
 221          * Remember the finalized features of our vdev, and provide it
 222          * to the remote processor once it is powered on.
 223          */
 224         rsc->gfeatures = vdev->features;
 225
 226         return 0;
 227 }
 228
 229 static void rproc_virtio_get(struct virtio_device *vdev, unsigned int offset,
 230                              void *buf, unsigned int len)
 231 {
 232         struct rproc_vdev *rvdev = vdev_to_rvdev(vdev);
 233         struct fw_rsc_vdev *rsc;
 234         void *cfg;
 235
 236         rsc = (void *)rvdev->rproc->table_ptr + rvdev->rsc_offset;
 237         cfg = &rsc->vring[rsc->num_of_vrings];
 238
 239         if (offset + len > rsc->config_len || offset + len < len) {
 240                 dev_err(&vdev->dev, "rproc_virtio_get: access out of bounds\n");
 241                 return;
 242         }
 243
 244         memcpy(buf, cfg + offset, len);
 245 }
 246
 247 static void rproc_virtio_set(struct virtio_device *vdev, unsigned int offset,
 248                              const void *buf, unsigned int len)
 249 {
 250         struct rproc_vdev *rvdev = vdev_to_rvdev(vdev);
 251         struct fw_rsc_vdev *rsc;
 252         void *cfg;
 253
 254         rsc = (void *)rvdev->rproc->table_ptr + rvdev->rsc_offset;
 255         cfg = &rsc->vring[rsc->num_of_vrings];
 256
 257         if (offset + len > rsc->config_len || offset + len < len) {
 258                 dev_err(&vdev->dev, "rproc_virtio_set: access out of bounds\n");
 259                 return;
 260         }
 261
 262         memcpy(cfg + offset, buf, len);
 263 }
 264
 265 static const struct virtio_config_ops rproc_virtio_config_ops = {
 266         .get_features   = rproc_virtio_get_features,
 267         .finalize_features = rproc_virtio_finalize_features,
 268         .find_vqs       = rproc_virtio_find_vqs,
 269         .del_vqs        = rproc_virtio_del_vqs,
 270         .reset          = rproc_virtio_reset,
 271         .set_status     = rproc_virtio_set_status,
 272         .get_status     = rproc_virtio_get_status,
 273         .get            = rproc_virtio_get,
 274         .set            = rproc_virtio_set,
 275 };
 276
 277 /*
 278  * This function is called whenever vdev is released, and is responsible
 279  * to decrement the remote processor's refcount which was taken when vdev was
 280  * added.
 281  *
 282  * Never call this function directly; it will be called by the driver
 283  * core when needed.
 284  */
 285 static void rproc_vdev_release(struct device *dev)
 286 {
 287         struct virtio_device *vdev = dev_to_virtio(dev);
 288         struct rproc_vdev *rvdev = vdev_to_rvdev(vdev);
 289         struct rproc *rproc = vdev_to_rproc(vdev);
 290
 291         list_del(&rvdev->node);
 292         kfree(rvdev);
 293
 294         put_device(&rproc->dev);
 295 }
 296
 297 /**
 298  * rproc_add_virtio_dev() - register an rproc-induced virtio device
 299  * @rvdev: the remote vdev
 300  *
 301  * This function registers a virtio device. This vdev's partent is
 302  * the rproc device.
 303  *
 304  * Returns 0 on success or an appropriate error value otherwise.
 305  */
 306 int rproc_add_virtio_dev(struct rproc_vdev *rvdev, int id)
 307 {
 308         struct rproc *rproc = rvdev->rproc;
 309         struct device *dev = &rproc->dev;
 310         struct virtio_device *vdev = &rvdev->vdev;
 311         int ret;
 312
 313         vdev->id.device = id,
 314         vdev->config = &rproc_virtio_config_ops,
 315         vdev->dev.parent = dev;
 316         vdev->dev.release = rproc_vdev_release;
 317
 318         /*
 319          * We're indirectly making a non-temporary copy of the rproc pointer
 320          * here, because drivers probed with this vdev will indirectly
 321          * access the wrapping rproc.
 322          *
 323          * Therefore we must increment the rproc refcount here, and decrement
 324          * it _only_ when the vdev is released.
 325          */
 326         get_device(&rproc->dev);
 327
 328         ret = register_virtio_device(vdev);
 329         if (ret) {
 330                 put_device(&rproc->dev);
 331                 dev_err(dev, "failed to register vdev: %d\n", ret);
 332                 goto out;
 333         }
 334
 335         dev_info(dev, "registered %s (type %d)\n", dev_name(&vdev->dev), id);
 336
 337 out:
 338         return ret;
 339 }
 340
 341 /**
 342  * rproc_remove_virtio_dev() - remove an rproc-induced virtio device
 343  * @rvdev: the remote vdev
 344  *
 345  * This function unregisters an existing virtio device.
 346  */
 347 void rproc_remove_virtio_dev(struct rproc_vdev *rvdev)
 348 {
 349         unregister_virtio_device(&rvdev->vdev);
 350 }