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, bool ctx)
  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;
  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         rvring = &rvdev->vring[id];
  92         addr = rvring->va;
  93         len = rvring->len;
  94
  95         /* zero vring */
  96         size = vring_size(len, rvring->align);
  97         memset(addr, 0, size);
  98
  99         dev_dbg(dev, "vring%d: va %p qsz %d notifyid %d\n",
 100                 id, addr, len, rvring->notifyid);
 101
 102         /*
 103          * Create the new vq, and tell virtio we're not interested in
 104          * the 'weak' smp barriers, since we're talking with a real device.
 105          */
 106         vq = vring_new_virtqueue(id, len, rvring->align, vdev, false, ctx,
 107                                  addr, rproc_virtio_notify, callback, name);
 108         if (!vq) {
 109                 dev_err(dev, "vring_new_virtqueue %s failed\n", name);
 110                 rproc_free_vring(rvring);
 111                 return ERR_PTR(-ENOMEM);
 112         }
 113
 114         rvring->vq = vq;
 115         vq->priv = rvring;
 116
 117         return vq;
 118 }
 119
 120 static void __rproc_virtio_del_vqs(struct virtio_device *vdev)
 121 {
 122         struct virtqueue *vq, *n;
 123         struct rproc_vring *rvring;
 124
 125         list_for_each_entry_safe(vq, n, &vdev->vqs, list) {
 126                 rvring = vq->priv;
 127                 rvring->vq = NULL;
 128                 vring_del_virtqueue(vq);
 129         }
 130 }
 131
 132 static void rproc_virtio_del_vqs(struct virtio_device *vdev)
 133 {
 134         __rproc_virtio_del_vqs(vdev);
 135 }
 136
 137 static int rproc_virtio_find_vqs(struct virtio_device *vdev, unsigned int nvqs,
 138                                  struct virtqueue *vqs[],
 139                                  vq_callback_t *callbacks[],
 140                                  const char * const names[],
 141                                  const bool * ctx,
 142                                  struct irq_affinity *desc)
 143 {
 144         int i, ret;
 145
 146         for (i = 0; i < nvqs; ++i) {
 147                 vqs[i] = rp_find_vq(vdev, i, callbacks[i], names[i],
 148                                     ctx ? ctx[i] : false);
 149                 if (IS_ERR(vqs[i])) {
 150                         ret = PTR_ERR(vqs[i]);
 151                         goto error;
 152                 }
 153         }
 154
 155         return 0;
 156
 157 error:
 158         __rproc_virtio_del_vqs(vdev);
 159         return ret;
 160 }
 161
 162 static u8 rproc_virtio_get_status(struct virtio_device *vdev)
 163 {
 164         struct rproc_vdev *rvdev = vdev_to_rvdev(vdev);
 165         struct fw_rsc_vdev *rsc;
 166
 167         rsc = (void *)rvdev->rproc->table_ptr + rvdev->rsc_offset;
 168
 169         return rsc->status;
 170 }
 171
 172 static void rproc_virtio_set_status(struct virtio_device *vdev, u8 status)
 173 {
 174         struct rproc_vdev *rvdev = vdev_to_rvdev(vdev);
 175         struct fw_rsc_vdev *rsc;
 176
 177         rsc = (void *)rvdev->rproc->table_ptr + rvdev->rsc_offset;
 178
 179         rsc->status = status;
 180         dev_dbg(&vdev->dev, "status: %d\n", status);
 181 }
 182
 183 static void rproc_virtio_reset(struct virtio_device *vdev)
 184 {
 185         struct rproc_vdev *rvdev = vdev_to_rvdev(vdev);
 186         struct fw_rsc_vdev *rsc;
 187
 188         rsc = (void *)rvdev->rproc->table_ptr + rvdev->rsc_offset;
 189
 190         rsc->status = 0;
 191         dev_dbg(&vdev->dev, "reset !\n");
 192 }
 193
 194 /* provide the vdev features as retrieved from the firmware */
 195 static u64 rproc_virtio_get_features(struct virtio_device *vdev)
 196 {
 197         struct rproc_vdev *rvdev = vdev_to_rvdev(vdev);
 198         struct fw_rsc_vdev *rsc;
 199
 200         rsc = (void *)rvdev->rproc->table_ptr + rvdev->rsc_offset;
 201
 202         return rsc->dfeatures;
 203 }
 204
 205 static int rproc_virtio_finalize_features(struct virtio_device *vdev)
 206 {
 207         struct rproc_vdev *rvdev = vdev_to_rvdev(vdev);
 208         struct fw_rsc_vdev *rsc;
 209
 210         rsc = (void *)rvdev->rproc->table_ptr + rvdev->rsc_offset;
 211
 212         /* Give virtio_ring a chance to accept features */
 213         vring_transport_features(vdev);
 214
 215         /* Make sure we don't have any features > 32 bits! */
 216         BUG_ON((u32)vdev->features != vdev->features);
 217
 218         /*
 219          * Remember the finalized features of our vdev, and provide it
 220          * to the remote processor once it is powered on.
 221          */
 222         rsc->gfeatures = vdev->features;
 223
 224         return 0;
 225 }
 226
 227 static void rproc_virtio_get(struct virtio_device *vdev, unsigned int offset,
 228                              void *buf, unsigned int len)
 229 {
 230         struct rproc_vdev *rvdev = vdev_to_rvdev(vdev);
 231         struct fw_rsc_vdev *rsc;
 232         void *cfg;
 233
 234         rsc = (void *)rvdev->rproc->table_ptr + rvdev->rsc_offset;
 235         cfg = &rsc->vring[rsc->num_of_vrings];
 236
 237         if (offset + len > rsc->config_len || offset + len < len) {
 238                 dev_err(&vdev->dev, "rproc_virtio_get: access out of bounds\n");
 239                 return;
 240         }
 241
 242         memcpy(buf, cfg + offset, len);
 243 }
 244
 245 static void rproc_virtio_set(struct virtio_device *vdev, unsigned int offset,
 246                              const void *buf, unsigned int len)
 247 {
 248         struct rproc_vdev *rvdev = vdev_to_rvdev(vdev);
 249         struct fw_rsc_vdev *rsc;
 250         void *cfg;
 251
 252         rsc = (void *)rvdev->rproc->table_ptr + rvdev->rsc_offset;
 253         cfg = &rsc->vring[rsc->num_of_vrings];
 254
 255         if (offset + len > rsc->config_len || offset + len < len) {
 256                 dev_err(&vdev->dev, "rproc_virtio_set: access out of bounds\n");
 257                 return;
 258         }
 259
 260         memcpy(cfg + offset, buf, len);
 261 }
 262
 263 static const struct virtio_config_ops rproc_virtio_config_ops = {
 264         .get_features   = rproc_virtio_get_features,
 265         .finalize_features = rproc_virtio_finalize_features,
 266         .find_vqs       = rproc_virtio_find_vqs,
 267         .del_vqs        = rproc_virtio_del_vqs,
 268         .reset          = rproc_virtio_reset,
 269         .set_status     = rproc_virtio_set_status,
 270         .get_status     = rproc_virtio_get_status,
 271         .get            = rproc_virtio_get,
 272         .set            = rproc_virtio_set,
 273 };
 274
 275 /*
 276  * This function is called whenever vdev is released, and is responsible
 277  * to decrement the remote processor's refcount which was taken when vdev was
 278  * added.
 279  *
 280  * Never call this function directly; it will be called by the driver
 281  * core when needed.
 282  */
 283 static void rproc_virtio_dev_release(struct device *dev)
 284 {
 285         struct virtio_device *vdev = dev_to_virtio(dev);
 286         struct rproc_vdev *rvdev = vdev_to_rvdev(vdev);
 287         struct rproc *rproc = vdev_to_rproc(vdev);
 288
 289         kref_put(&rvdev->refcount, rproc_vdev_release);
 290
 291         put_device(&rproc->dev);
 292 }
 293
 294 /**
 295  * rproc_add_virtio_dev() - register an rproc-induced virtio device
 296  * @rvdev: the remote vdev
 297  *
 298  * This function registers a virtio device. This vdev's partent is
 299  * the rproc device.
 300  *
 301  * Returns 0 on success or an appropriate error value otherwise.
 302  */
 303 int rproc_add_virtio_dev(struct rproc_vdev *rvdev, int id)
 304 {
 305         struct rproc *rproc = rvdev->rproc;
 306         struct device *dev = &rproc->dev;
 307         struct virtio_device *vdev = &rvdev->vdev;
 308         int ret;
 309
 310         vdev->id.device = id,
 311         vdev->config = &rproc_virtio_config_ops,
 312         vdev->dev.parent = dev;
 313         vdev->dev.release = rproc_virtio_dev_release;
 314
 315         /*
 316          * We're indirectly making a non-temporary copy of the rproc pointer
 317          * here, because drivers probed with this vdev will indirectly
 318          * access the wrapping rproc.
 319          *
 320          * Therefore we must increment the rproc refcount here, and decrement
 321          * it _only_ when the vdev is released.
 322          */
 323         get_device(&rproc->dev);
 324
 325         /* Reference the vdev and vring allocations */
 326         kref_get(&rvdev->refcount);
 327
 328         ret = register_virtio_device(vdev);
 329         if (ret) {
 330                 put_device(&vdev->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 }