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