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_mem_entry *mem;
  80         struct rproc_vring *rvring;
  81         struct fw_rsc_vdev *rsc;
  82         struct virtqueue *vq;
  83         void *addr;
  84         int len, size;
  85
  86         /* we're temporarily limited to two virtqueues per rvdev */
  87         if (id >= ARRAY_SIZE(rvdev->vring))
  88                 return ERR_PTR(-EINVAL);
  89
  90         if (!name)
  91                 return NULL;
  92
  93         /* Search allocated memory region by name */
  94         mem = rproc_find_carveout_by_name(rproc, "vdev%dvring%d", rvdev->index,
  95                                           id);
  96         if (!mem || !mem->va)
  97                 return ERR_PTR(-ENOMEM);
  98
  99         rvring = &rvdev->vring[id];
 100         addr = mem->va;
 101         len = rvring->len;
 102
 103         /* zero vring */
 104         size = vring_size(len, rvring->align);
 105         memset(addr, 0, size);
 106
 107         dev_dbg(dev, "vring%d: va %pK qsz %d notifyid %d\n",
 108                 id, addr, len, rvring->notifyid);
 109
 110         /*
 111          * Create the new vq, and tell virtio we're not interested in
 112          * the 'weak' smp barriers, since we're talking with a real device.
 113          */
 114         vq = vring_new_virtqueue(id, len, rvring->align, vdev, false, ctx,
 115                                  addr, rproc_virtio_notify, callback, name);
 116         if (!vq) {
 117                 dev_err(dev, "vring_new_virtqueue %s failed\n", name);
 118                 rproc_free_vring(rvring);
 119                 return ERR_PTR(-ENOMEM);
 120         }
 121
 122         rvring->vq = vq;
 123         vq->priv = rvring;
 124
 125         /* Update vring in resource table */
 126         rsc = (void *)rproc->table_ptr + rvdev->rsc_offset;
 127         rsc->vring[id].da = mem->da;
 128
 129         return vq;
 130 }
 131
 132 static void __rproc_virtio_del_vqs(struct virtio_device *vdev)
 133 {
 134         struct virtqueue *vq, *n;
 135         struct rproc_vring *rvring;
 136
 137         list_for_each_entry_safe(vq, n, &vdev->vqs, list) {
 138                 rvring = vq->priv;
 139                 rvring->vq = NULL;
 140                 vring_del_virtqueue(vq);
 141         }
 142 }
 143
 144 static void rproc_virtio_del_vqs(struct virtio_device *vdev)
 145 {
 146         __rproc_virtio_del_vqs(vdev);
 147 }
 148
 149 static int rproc_virtio_find_vqs(struct virtio_device *vdev, unsigned int nvqs,
 150                                  struct virtqueue *vqs[],
 151                                  vq_callback_t *callbacks[],
 152                                  const char * const names[],
 153                                  const bool * ctx,
 154                                  struct irq_affinity *desc)
 155 {
 156         int i, ret, queue_idx = 0;
 157
 158         for (i = 0; i < nvqs; ++i) {
 159                 if (!names[i]) {
 160                         vqs[i] = NULL;
 161                         continue;
 162                 }
 163
 164                 vqs[i] = rp_find_vq(vdev, queue_idx++, callbacks[i], names[i],
 165                                     ctx ? ctx[i] : false);
 166                 if (IS_ERR(vqs[i])) {
 167                         ret = PTR_ERR(vqs[i]);
 168                         goto error;
 169                 }
 170         }
 171
 172         return 0;
 173
 174 error:
 175         __rproc_virtio_del_vqs(vdev);
 176         return ret;
 177 }
 178
 179 static u8 rproc_virtio_get_status(struct virtio_device *vdev)
 180 {
 181         struct rproc_vdev *rvdev = vdev_to_rvdev(vdev);
 182         struct fw_rsc_vdev *rsc;
 183
 184         rsc = (void *)rvdev->rproc->table_ptr + rvdev->rsc_offset;
 185
 186         return rsc->status;
 187 }
 188
 189 static void rproc_virtio_set_status(struct virtio_device *vdev, u8 status)
 190 {
 191         struct rproc_vdev *rvdev = vdev_to_rvdev(vdev);
 192         struct fw_rsc_vdev *rsc;
 193
 194         rsc = (void *)rvdev->rproc->table_ptr + rvdev->rsc_offset;
 195
 196         rsc->status = status;
 197         dev_dbg(&vdev->dev, "status: %d\n", status);
 198 }
 199
 200 static void rproc_virtio_reset(struct virtio_device *vdev)
 201 {
 202         struct rproc_vdev *rvdev = vdev_to_rvdev(vdev);
 203         struct fw_rsc_vdev *rsc;
 204
 205         rsc = (void *)rvdev->rproc->table_ptr + rvdev->rsc_offset;
 206
 207         rsc->status = 0;
 208         dev_dbg(&vdev->dev, "reset !\n");
 209 }
 210
 211 /* provide the vdev features as retrieved from the firmware */
 212 static u64 rproc_virtio_get_features(struct virtio_device *vdev)
 213 {
 214         struct rproc_vdev *rvdev = vdev_to_rvdev(vdev);
 215         struct fw_rsc_vdev *rsc;
 216
 217         rsc = (void *)rvdev->rproc->table_ptr + rvdev->rsc_offset;
 218
 219         return rsc->dfeatures;
 220 }
 221
 222 static void rproc_transport_features(struct virtio_device *vdev)
 223 {
 224         /*
 225          * Packed ring isn't enabled on remoteproc for now,
 226          * because remoteproc uses vring_new_virtqueue() which
 227          * creates virtio rings on preallocated memory.
 228          */
 229         __virtio_clear_bit(vdev, VIRTIO_F_RING_PACKED);
 230 }
 231
 232 static int rproc_virtio_finalize_features(struct virtio_device *vdev)
 233 {
 234         struct rproc_vdev *rvdev = vdev_to_rvdev(vdev);
 235         struct fw_rsc_vdev *rsc;
 236
 237         rsc = (void *)rvdev->rproc->table_ptr + rvdev->rsc_offset;
 238
 239         /* Give virtio_ring a chance to accept features */
 240         vring_transport_features(vdev);
 241
 242         /* Give virtio_rproc a chance to accept features. */
 243         rproc_transport_features(vdev);
 244
 245         /* Make sure we don't have any features > 32 bits! */
 246         BUG_ON((u32)vdev->features != vdev->features);
 247
 248         /*
 249          * Remember the finalized features of our vdev, and provide it
 250          * to the remote processor once it is powered on.
 251          */
 252         rsc->gfeatures = vdev->features;
 253
 254         return 0;
 255 }
 256
 257 static void rproc_virtio_get(struct virtio_device *vdev, unsigned int offset,
 258                              void *buf, unsigned int len)
 259 {
 260         struct rproc_vdev *rvdev = vdev_to_rvdev(vdev);
 261         struct fw_rsc_vdev *rsc;
 262         void *cfg;
 263
 264         rsc = (void *)rvdev->rproc->table_ptr + rvdev->rsc_offset;
 265         cfg = &rsc->vring[rsc->num_of_vrings];
 266
 267         if (offset + len > rsc->config_len || offset + len < len) {
 268                 dev_err(&vdev->dev, "rproc_virtio_get: access out of bounds\n");
 269                 return;
 270         }
 271
 272         memcpy(buf, cfg + offset, len);
 273 }
 274
 275 static void rproc_virtio_set(struct virtio_device *vdev, unsigned int offset,
 276                              const void *buf, unsigned int len)
 277 {
 278         struct rproc_vdev *rvdev = vdev_to_rvdev(vdev);
 279         struct fw_rsc_vdev *rsc;
 280         void *cfg;
 281
 282         rsc = (void *)rvdev->rproc->table_ptr + rvdev->rsc_offset;
 283         cfg = &rsc->vring[rsc->num_of_vrings];
 284
 285         if (offset + len > rsc->config_len || offset + len < len) {
 286                 dev_err(&vdev->dev, "rproc_virtio_set: access out of bounds\n");
 287                 return;
 288         }
 289
 290         memcpy(cfg + offset, buf, len);
 291 }
 292
 293 static const struct virtio_config_ops rproc_virtio_config_ops = {
 294         .get_features   = rproc_virtio_get_features,
 295         .finalize_features = rproc_virtio_finalize_features,
 296         .find_vqs       = rproc_virtio_find_vqs,
 297         .del_vqs        = rproc_virtio_del_vqs,
 298         .reset          = rproc_virtio_reset,
 299         .set_status     = rproc_virtio_set_status,
 300         .get_status     = rproc_virtio_get_status,
 301         .get            = rproc_virtio_get,
 302         .set            = rproc_virtio_set,
 303 };
 304
 305 /*
 306  * This function is called whenever vdev is released, and is responsible
 307  * to decrement the remote processor's refcount which was taken when vdev was
 308  * added.
 309  *
 310  * Never call this function directly; it will be called by the driver
 311  * core when needed.
 312  */
 313 static void rproc_virtio_dev_release(struct device *dev)
 314 {
 315         struct virtio_device *vdev = dev_to_virtio(dev);
 316         struct rproc_vdev *rvdev = vdev_to_rvdev(vdev);
 317         struct rproc *rproc = vdev_to_rproc(vdev);
 318
 319         kref_put(&rvdev->refcount, rproc_vdev_release);
 320
 321         put_device(&rproc->dev);
 322 }
 323
 324 /**
 325  * rproc_add_virtio_dev() - register an rproc-induced virtio device
 326  * @rvdev: the remote vdev
 327  *
 328  * This function registers a virtio device. This vdev's partent is
 329  * the rproc device.
 330  *
 331  * Returns 0 on success or an appropriate error value otherwise.
 332  */
 333 int rproc_add_virtio_dev(struct rproc_vdev *rvdev, int id)
 334 {
 335         struct rproc *rproc = rvdev->rproc;
 336         struct device *dev = &rproc->dev;
 337         struct virtio_device *vdev = &rvdev->vdev;
 338         int ret;
 339
 340         vdev->id.device = id,
 341         vdev->config = &rproc_virtio_config_ops,
 342         vdev->dev.parent = dev;
 343         vdev->dev.release = rproc_virtio_dev_release;
 344
 345         /*
 346          * We're indirectly making a non-temporary copy of the rproc pointer
 347          * here, because drivers probed with this vdev will indirectly
 348          * access the wrapping rproc.
 349          *
 350          * Therefore we must increment the rproc refcount here, and decrement
 351          * it _only_ when the vdev is released.
 352          */
 353         get_device(&rproc->dev);
 354
 355         /* Reference the vdev and vring allocations */
 356         kref_get(&rvdev->refcount);
 357
 358         ret = register_virtio_device(vdev);
 359         if (ret) {
 360                 put_device(&vdev->dev);
 361                 dev_err(dev, "failed to register vdev: %d\n", ret);
 362                 goto out;
 363         }
 364
 365         dev_info(dev, "registered %s (type %d)\n", dev_name(&vdev->dev), id);
 366
 367 out:
 368         return ret;
 369 }
 370
 371 /**
 372  * rproc_remove_virtio_dev() - remove an rproc-induced virtio device
 373  * @rvdev: the remote vdev
 374  *
 375  * This function unregisters an existing virtio device.
 376  */
 377 void rproc_remove_virtio_dev(struct rproc_vdev *rvdev)
 378 {
 379         unregister_virtio_device(&rvdev->vdev);
 380 }