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 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         struct rproc *rproc = vdev_to_rproc(vdev);
 140
 141         /* power down the remote processor before deleting vqs */
 142         rproc_shutdown(rproc);
 143
 144         __rproc_virtio_del_vqs(vdev);
 145 }
 146
 147 static int rproc_virtio_find_vqs(struct virtio_device *vdev, unsigned nvqs,
 148                        struct virtqueue *vqs[],
 149                        vq_callback_t *callbacks[],
 150                        const char * const names[])
 151 {
 152         struct rproc *rproc = vdev_to_rproc(vdev);
 153         int i, ret;
 154
 155         for (i = 0; i < nvqs; ++i) {
 156                 vqs[i] = rp_find_vq(vdev, i, callbacks[i], names[i]);
 157                 if (IS_ERR(vqs[i])) {
 158                         ret = PTR_ERR(vqs[i]);
 159                         goto error;
 160                 }
 161         }
 162
 163         /* now that the vqs are all set, boot the remote processor */
 164         ret = rproc_boot(rproc);
 165         if (ret) {
 166                 dev_err(&rproc->dev, "rproc_boot() failed %d\n", ret);
 167                 goto error;
 168         }
 169
 170         return 0;
 171
 172 error:
 173         __rproc_virtio_del_vqs(vdev);
 174         return ret;
 175 }
 176
 177 static u8 rproc_virtio_get_status(struct virtio_device *vdev)
 178 {
 179         struct rproc_vdev *rvdev = vdev_to_rvdev(vdev);
 180         struct fw_rsc_vdev *rsc;
 181
 182         rsc = (void *)rvdev->rproc->table_ptr + rvdev->rsc_offset;
 183
 184         return rsc->status;
 185 }
 186
 187 static void rproc_virtio_set_status(struct virtio_device *vdev, u8 status)
 188 {
 189         struct rproc_vdev *rvdev = vdev_to_rvdev(vdev);
 190         struct fw_rsc_vdev *rsc;
 191
 192         rsc = (void *)rvdev->rproc->table_ptr + rvdev->rsc_offset;
 193
 194         rsc->status = status;
 195         dev_dbg(&vdev->dev, "status: %d\n", status);
 196 }
 197
 198 static void rproc_virtio_reset(struct virtio_device *vdev)
 199 {
 200         struct rproc_vdev *rvdev = vdev_to_rvdev(vdev);
 201         struct fw_rsc_vdev *rsc;
 202
 203         rsc = (void *)rvdev->rproc->table_ptr + rvdev->rsc_offset;
 204
 205         rsc->status = 0;
 206         dev_dbg(&vdev->dev, "reset !\n");
 207 }
 208
 209 /* provide the vdev features as retrieved from the firmware */
 210 static u64 rproc_virtio_get_features(struct virtio_device *vdev)
 211 {
 212         struct rproc_vdev *rvdev = vdev_to_rvdev(vdev);
 213         struct fw_rsc_vdev *rsc;
 214
 215         rsc = (void *)rvdev->rproc->table_ptr + rvdev->rsc_offset;
 216
 217         return rsc->dfeatures;
 218 }
 219
 220 static int rproc_virtio_finalize_features(struct virtio_device *vdev)
 221 {
 222         struct rproc_vdev *rvdev = vdev_to_rvdev(vdev);
 223         struct fw_rsc_vdev *rsc;
 224
 225         rsc = (void *)rvdev->rproc->table_ptr + rvdev->rsc_offset;
 226
 227         /* Give virtio_ring a chance to accept features */
 228         vring_transport_features(vdev);
 229
 230         /* Make sure we don't have any features > 32 bits! */
 231         BUG_ON((u32)vdev->features != vdev->features);
 232
 233         /*
 234          * Remember the finalized features of our vdev, and provide it
 235          * to the remote processor once it is powered on.
 236          */
 237         rsc->gfeatures = vdev->features;
 238
 239         return 0;
 240 }
 241
 242 static void rproc_virtio_get(struct virtio_device *vdev, unsigned offset,
 243                                                         void *buf, unsigned 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_get: access out of bounds\n");
 254                 return;
 255         }
 256
 257         memcpy(buf, cfg + offset, len);
 258 }
 259
 260 static void rproc_virtio_set(struct virtio_device *vdev, unsigned offset,
 261                       const void *buf, unsigned len)
 262 {
 263         struct rproc_vdev *rvdev = vdev_to_rvdev(vdev);
 264         struct fw_rsc_vdev *rsc;
 265         void *cfg;
 266
 267         rsc = (void *)rvdev->rproc->table_ptr + rvdev->rsc_offset;
 268         cfg = &rsc->vring[rsc->num_of_vrings];
 269
 270         if (offset + len > rsc->config_len || offset + len < len) {
 271                 dev_err(&vdev->dev, "rproc_virtio_set: access out of bounds\n");
 272                 return;
 273         }
 274
 275         memcpy(cfg + offset, buf, len);
 276 }
 277
 278 static const struct virtio_config_ops rproc_virtio_config_ops = {
 279         .get_features   = rproc_virtio_get_features,
 280         .finalize_features = rproc_virtio_finalize_features,
 281         .find_vqs       = rproc_virtio_find_vqs,
 282         .del_vqs        = rproc_virtio_del_vqs,
 283         .reset          = rproc_virtio_reset,
 284         .set_status     = rproc_virtio_set_status,
 285         .get_status     = rproc_virtio_get_status,
 286         .get            = rproc_virtio_get,
 287         .set            = rproc_virtio_set,
 288 };
 289
 290 /*
 291  * This function is called whenever vdev is released, and is responsible
 292  * to decrement the remote processor's refcount which was taken when vdev was
 293  * added.
 294  *
 295  * Never call this function directly; it will be called by the driver
 296  * core when needed.
 297  */
 298 static void rproc_vdev_release(struct device *dev)
 299 {
 300         struct virtio_device *vdev = dev_to_virtio(dev);
 301         struct rproc_vdev *rvdev = vdev_to_rvdev(vdev);
 302         struct rproc *rproc = vdev_to_rproc(vdev);
 303
 304         list_del(&rvdev->node);
 305         kfree(rvdev);
 306
 307         put_device(&rproc->dev);
 308 }
 309
 310 /**
 311  * rproc_add_virtio_dev() - register an rproc-induced virtio device
 312  * @rvdev: the remote vdev
 313  *
 314  * This function registers a virtio device. This vdev's partent is
 315  * the rproc device.
 316  *
 317  * Returns 0 on success or an appropriate error value otherwise.
 318  */
 319 int rproc_add_virtio_dev(struct rproc_vdev *rvdev, int id)
 320 {
 321         struct rproc *rproc = rvdev->rproc;
 322         struct device *dev = &rproc->dev;
 323         struct virtio_device *vdev = &rvdev->vdev;
 324         int ret;
 325
 326         vdev->id.device = id,
 327         vdev->config = &rproc_virtio_config_ops,
 328         vdev->dev.parent = dev;
 329         vdev->dev.release = rproc_vdev_release;
 330
 331         /*
 332          * We're indirectly making a non-temporary copy of the rproc pointer
 333          * here, because drivers probed with this vdev will indirectly
 334          * access the wrapping rproc.
 335          *
 336          * Therefore we must increment the rproc refcount here, and decrement
 337          * it _only_ when the vdev is released.
 338          */
 339         get_device(&rproc->dev);
 340
 341         ret = register_virtio_device(vdev);
 342         if (ret) {
 343                 put_device(&rproc->dev);
 344                 dev_err(dev, "failed to register vdev: %d\n", ret);
 345                 goto out;
 346         }
 347
 348         dev_info(dev, "registered %s (type %d)\n", dev_name(&vdev->dev), id);
 349
 350 out:
 351         return ret;
 352 }
 353
 354 /**
 355  * rproc_remove_virtio_dev() - remove an rproc-induced virtio device
 356  * @rvdev: the remote vdev
 357  *
 358  * This function unregisters an existing virtio device.
 359  */
 360 void rproc_remove_virtio_dev(struct rproc_vdev *rvdev)
 361 {
 362         unregister_virtio_device(&rvdev->vdev);
 363 }