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;
  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, addr,
 107                                  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                                  struct irq_affinity *desc)
 142 {
 143         int i, ret;
 144
 145         for (i = 0; i < nvqs; ++i) {
 146                 vqs[i] = rp_find_vq(vdev, i, callbacks[i], names[i]);
 147                 if (IS_ERR(vqs[i])) {
 148                         ret = PTR_ERR(vqs[i]);
 149                         goto error;
 150                 }
 151         }
 152
 153         return 0;
 154
 155 error:
 156         __rproc_virtio_del_vqs(vdev);
 157         return ret;
 158 }
 159
 160 static u8 rproc_virtio_get_status(struct virtio_device *vdev)
 161 {
 162         struct rproc_vdev *rvdev = vdev_to_rvdev(vdev);
 163         struct fw_rsc_vdev *rsc;
 164
 165         rsc = (void *)rvdev->rproc->table_ptr + rvdev->rsc_offset;
 166
 167         return rsc->status;
 168 }
 169
 170 static void rproc_virtio_set_status(struct virtio_device *vdev, u8 status)
 171 {
 172         struct rproc_vdev *rvdev = vdev_to_rvdev(vdev);
 173         struct fw_rsc_vdev *rsc;
 174
 175         rsc = (void *)rvdev->rproc->table_ptr + rvdev->rsc_offset;
 176
 177         rsc->status = status;
 178         dev_dbg(&vdev->dev, "status: %d\n", status);
 179 }
 180
 181 static void rproc_virtio_reset(struct virtio_device *vdev)
 182 {
 183         struct rproc_vdev *rvdev = vdev_to_rvdev(vdev);
 184         struct fw_rsc_vdev *rsc;
 185
 186         rsc = (void *)rvdev->rproc->table_ptr + rvdev->rsc_offset;
 187
 188         rsc->status = 0;
 189         dev_dbg(&vdev->dev, "reset !\n");
 190 }
 191
 192 /* provide the vdev features as retrieved from the firmware */
 193 static u64 rproc_virtio_get_features(struct virtio_device *vdev)
 194 {
 195         struct rproc_vdev *rvdev = vdev_to_rvdev(vdev);
 196         struct fw_rsc_vdev *rsc;
 197
 198         rsc = (void *)rvdev->rproc->table_ptr + rvdev->rsc_offset;
 199
 200         return rsc->dfeatures;
 201 }
 202
 203 static int rproc_virtio_finalize_features(struct virtio_device *vdev)
 204 {
 205         struct rproc_vdev *rvdev = vdev_to_rvdev(vdev);
 206         struct fw_rsc_vdev *rsc;
 207
 208         rsc = (void *)rvdev->rproc->table_ptr + rvdev->rsc_offset;
 209
 210         /* Give virtio_ring a chance to accept features */
 211         vring_transport_features(vdev);
 212
 213         /* Make sure we don't have any features > 32 bits! */
 214         BUG_ON((u32)vdev->features != vdev->features);
 215
 216         /*
 217          * Remember the finalized features of our vdev, and provide it
 218          * to the remote processor once it is powered on.
 219          */
 220         rsc->gfeatures = vdev->features;
 221
 222         return 0;
 223 }
 224
 225 static void rproc_virtio_get(struct virtio_device *vdev, unsigned int offset,
 226                              void *buf, unsigned int len)
 227 {
 228         struct rproc_vdev *rvdev = vdev_to_rvdev(vdev);
 229         struct fw_rsc_vdev *rsc;
 230         void *cfg;
 231
 232         rsc = (void *)rvdev->rproc->table_ptr + rvdev->rsc_offset;
 233         cfg = &rsc->vring[rsc->num_of_vrings];
 234
 235         if (offset + len > rsc->config_len || offset + len < len) {
 236                 dev_err(&vdev->dev, "rproc_virtio_get: access out of bounds\n");
 237                 return;
 238         }
 239
 240         memcpy(buf, cfg + offset, len);
 241 }
 242
 243 static void rproc_virtio_set(struct virtio_device *vdev, unsigned int offset,
 244                              const void *buf, unsigned int len)
 245 {
 246         struct rproc_vdev *rvdev = vdev_to_rvdev(vdev);
 247         struct fw_rsc_vdev *rsc;
 248         void *cfg;
 249
 250         rsc = (void *)rvdev->rproc->table_ptr + rvdev->rsc_offset;
 251         cfg = &rsc->vring[rsc->num_of_vrings];
 252
 253         if (offset + len > rsc->config_len || offset + len < len) {
 254                 dev_err(&vdev->dev, "rproc_virtio_set: access out of bounds\n");
 255                 return;
 256         }
 257
 258         memcpy(cfg + offset, buf, len);
 259 }
 260
 261 static const struct virtio_config_ops rproc_virtio_config_ops = {
 262         .get_features   = rproc_virtio_get_features,
 263         .finalize_features = rproc_virtio_finalize_features,
 264         .find_vqs       = rproc_virtio_find_vqs,
 265         .del_vqs        = rproc_virtio_del_vqs,
 266         .reset          = rproc_virtio_reset,
 267         .set_status     = rproc_virtio_set_status,
 268         .get_status     = rproc_virtio_get_status,
 269         .get            = rproc_virtio_get,
 270         .set            = rproc_virtio_set,
 271 };
 272
 273 /*
 274  * This function is called whenever vdev is released, and is responsible
 275  * to decrement the remote processor's refcount which was taken when vdev was
 276  * added.
 277  *
 278  * Never call this function directly; it will be called by the driver
 279  * core when needed.
 280  */
 281 static void rproc_virtio_dev_release(struct device *dev)
 282 {
 283         struct virtio_device *vdev = dev_to_virtio(dev);
 284         struct rproc_vdev *rvdev = vdev_to_rvdev(vdev);
 285         struct rproc *rproc = vdev_to_rproc(vdev);
 286
 287         kref_put(&rvdev->refcount, rproc_vdev_release);
 288
 289         put_device(&rproc->dev);
 290 }
 291
 292 /**
 293  * rproc_add_virtio_dev() - register an rproc-induced virtio device
 294  * @rvdev: the remote vdev
 295  *
 296  * This function registers a virtio device. This vdev's partent is
 297  * the rproc device.
 298  *
 299  * Returns 0 on success or an appropriate error value otherwise.
 300  */
 301 int rproc_add_virtio_dev(struct rproc_vdev *rvdev, int id)
 302 {
 303         struct rproc *rproc = rvdev->rproc;
 304         struct device *dev = &rproc->dev;
 305         struct virtio_device *vdev = &rvdev->vdev;
 306         int ret;
 307
 308         vdev->id.device = id,
 309         vdev->config = &rproc_virtio_config_ops,
 310         vdev->dev.parent = dev;
 311         vdev->dev.release = rproc_virtio_dev_release;
 312
 313         /*
 314          * We're indirectly making a non-temporary copy of the rproc pointer
 315          * here, because drivers probed with this vdev will indirectly
 316          * access the wrapping rproc.
 317          *
 318          * Therefore we must increment the rproc refcount here, and decrement
 319          * it _only_ when the vdev is released.
 320          */
 321         get_device(&rproc->dev);
 322
 323         /* Reference the vdev and vring allocations */
 324         kref_get(&rvdev->refcount);
 325
 326         ret = register_virtio_device(vdev);
 327         if (ret) {
 328                 put_device(&rproc->dev);
 329                 dev_err(dev, "failed to register vdev: %d\n", ret);
 330                 goto out;
 331         }
 332
 333         dev_info(dev, "registered %s (type %d)\n", dev_name(&vdev->dev), id);
 334
 335 out:
 336         return ret;
 337 }
 338
 339 /**
 340  * rproc_remove_virtio_dev() - remove an rproc-induced virtio device
 341  * @rvdev: the remote vdev
 342  *
 343  * This function unregisters an existing virtio device.
 344  */
 345 void rproc_remove_virtio_dev(struct rproc_vdev *rvdev)
 346 {
 347         unregister_virtio_device(&rvdev->vdev);
 348 }