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 void 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 }
  43
  44 /**
  45  * rproc_vq_interrupt() - tell remoteproc that a virtqueue is interrupted
  46  * @rproc: handle to the remote processor
  47  * @notifyid: index of the signalled virtqueue (unique per this @rproc)
  48  *
  49  * This function should be called by the platform-specific rproc driver,
  50  * when the remote processor signals that a specific virtqueue has pending
  51  * messages available.
  52  *
  53  * Returns IRQ_NONE if no message was found in the @notifyid virtqueue,
  54  * and otherwise returns IRQ_HANDLED.
  55  */
  56 irqreturn_t rproc_vq_interrupt(struct rproc *rproc, int notifyid)
  57 {
  58         struct rproc_vring *rvring;
  59
  60         dev_dbg(rproc->dev, "vq index %d is interrupted\n", notifyid);
  61
  62         rvring = idr_find(&rproc->notifyids, notifyid);
  63         if (!rvring || !rvring->vq)
  64                 return IRQ_NONE;
  65
  66         return vring_interrupt(0, rvring->vq);
  67 }
  68 EXPORT_SYMBOL(rproc_vq_interrupt);
  69
  70 static struct virtqueue *rp_find_vq(struct virtio_device *vdev,
  71                                     unsigned id,
  72                                     void (*callback)(struct virtqueue *vq),
  73                                     const char *name)
  74 {
  75         struct rproc_vdev *rvdev = vdev_to_rvdev(vdev);
  76         struct rproc *rproc = vdev_to_rproc(vdev);
  77         struct rproc_vring *rvring;
  78         struct virtqueue *vq;
  79         void *addr;
  80         int len, size;
  81
  82         /* we're temporarily limited to two virtqueues per rvdev */
  83         if (id >= ARRAY_SIZE(rvdev->vring))
  84                 return ERR_PTR(-EINVAL);
  85
  86         rvring = &rvdev->vring[id];
  87
  88         addr = rvring->va;
  89         len = rvring->len;
  90
  91         /* zero vring */
  92         size = vring_size(len, rvring->align);
  93         memset(addr, 0, size);
  94
  95         dev_dbg(rproc->dev, "vring%d: va %p qsz %d notifyid %d\n",
  96                                         id, addr, len, rvring->notifyid);
  97
  98         /*
  99          * Create the new vq, and tell virtio we're not interested in
 100          * the 'weak' smp barriers, since we're talking with a real device.
 101          */
 102         vq = vring_new_virtqueue(len, rvring->align, vdev, false, addr,
 103                                         rproc_virtio_notify, callback, name);
 104         if (!vq) {
 105                 dev_err(rproc->dev, "vring_new_virtqueue %s failed\n", name);
 106                 return ERR_PTR(-ENOMEM);
 107         }
 108
 109         rvring->vq = vq;
 110         vq->priv = rvring;
 111
 112         return vq;
 113 }
 114
 115 static void rproc_virtio_del_vqs(struct virtio_device *vdev)
 116 {
 117         struct virtqueue *vq, *n;
 118         struct rproc *rproc = vdev_to_rproc(vdev);
 119         struct rproc_vring *rvring;
 120
 121         /* power down the remote processor before deleting vqs */
 122         rproc_shutdown(rproc);
 123
 124         list_for_each_entry_safe(vq, n, &vdev->vqs, list) {
 125                 rvring = vq->priv;
 126                 rvring->vq = NULL;
 127                 vring_del_virtqueue(vq);
 128         }
 129 }
 130
 131 static int rproc_virtio_find_vqs(struct virtio_device *vdev, unsigned nvqs,
 132                        struct virtqueue *vqs[],
 133                        vq_callback_t *callbacks[],
 134                        const char *names[])
 135 {
 136         struct rproc *rproc = vdev_to_rproc(vdev);
 137         int i, ret;
 138
 139         for (i = 0; i < nvqs; ++i) {
 140                 vqs[i] = rp_find_vq(vdev, i, callbacks[i], names[i]);
 141                 if (IS_ERR(vqs[i])) {
 142                         ret = PTR_ERR(vqs[i]);
 143                         goto error;
 144                 }
 145         }
 146
 147         /* now that the vqs are all set, boot the remote processor */
 148         ret = rproc_boot(rproc);
 149         if (ret) {
 150                 dev_err(rproc->dev, "rproc_boot() failed %d\n", ret);
 151                 goto error;
 152         }
 153
 154         return 0;
 155
 156 error:
 157         rproc_virtio_del_vqs(vdev);
 158         return ret;
 159 }
 160
 161 /*
 162  * We don't support yet real virtio status semantics.
 163  *
 164  * The plan is to provide this via the VDEV resource entry
 165  * which is part of the firmware: this way the remote processor
 166  * will be able to access the status values as set by us.
 167  */
 168 static u8 rproc_virtio_get_status(struct virtio_device *vdev)
 169 {
 170         return 0;
 171 }
 172
 173 static void rproc_virtio_set_status(struct virtio_device *vdev, u8 status)
 174 {
 175         dev_dbg(&vdev->dev, "status: %d\n", status);
 176 }
 177
 178 static void rproc_virtio_reset(struct virtio_device *vdev)
 179 {
 180         dev_dbg(&vdev->dev, "reset !\n");
 181 }
 182
 183 /* provide the vdev features as retrieved from the firmware */
 184 static u32 rproc_virtio_get_features(struct virtio_device *vdev)
 185 {
 186         struct rproc_vdev *rvdev = vdev_to_rvdev(vdev);
 187
 188         return rvdev->dfeatures;
 189 }
 190
 191 static void rproc_virtio_finalize_features(struct virtio_device *vdev)
 192 {
 193         struct rproc_vdev *rvdev = vdev_to_rvdev(vdev);
 194
 195         /* Give virtio_ring a chance to accept features */
 196         vring_transport_features(vdev);
 197
 198         /*
 199          * Remember the finalized features of our vdev, and provide it
 200          * to the remote processor once it is powered on.
 201          *
 202          * Similarly to the status field, we don't expose yet the negotiated
 203          * features to the remote processors at this point. This will be
 204          * fixed as part of a small resource table overhaul and then an
 205          * extension of the virtio resource entries.
 206          */
 207         rvdev->gfeatures = vdev->features[0];
 208 }
 209
 210 static struct virtio_config_ops rproc_virtio_config_ops = {
 211         .get_features   = rproc_virtio_get_features,
 212         .finalize_features = rproc_virtio_finalize_features,
 213         .find_vqs       = rproc_virtio_find_vqs,
 214         .del_vqs        = rproc_virtio_del_vqs,
 215         .reset          = rproc_virtio_reset,
 216         .set_status     = rproc_virtio_set_status,
 217         .get_status     = rproc_virtio_get_status,
 218 };
 219
 220 /*
 221  * This function is called whenever vdev is released, and is responsible
 222  * to decrement the remote processor's refcount taken when vdev was
 223  * added.
 224  *
 225  * Never call this function directly; it will be called by the driver
 226  * core when needed.
 227  */
 228 static void rproc_vdev_release(struct device *dev)
 229 {
 230         struct virtio_device *vdev = dev_to_virtio(dev);
 231         struct rproc *rproc = vdev_to_rproc(vdev);
 232
 233         kref_put(&rproc->refcount, rproc_release);
 234 }
 235
 236 /**
 237  * rproc_add_virtio_dev() - register an rproc-induced virtio device
 238  * @rvdev: the remote vdev
 239  *
 240  * This function registers a virtio device. This vdev's partent is
 241  * the rproc device.
 242  *
 243  * Returns 0 on success or an appropriate error value otherwise.
 244  */
 245 int rproc_add_virtio_dev(struct rproc_vdev *rvdev, int id)
 246 {
 247         struct rproc *rproc = rvdev->rproc;
 248         struct device *dev = rproc->dev;
 249         struct virtio_device *vdev = &rvdev->vdev;
 250         int ret;
 251
 252         vdev->id.device = id,
 253         vdev->config = &rproc_virtio_config_ops,
 254         vdev->dev.parent = dev;
 255         vdev->dev.release = rproc_vdev_release;
 256
 257         /*
 258          * We're indirectly making a non-temporary copy of the rproc pointer
 259          * here, because drivers probed with this vdev will indirectly
 260          * access the wrapping rproc.
 261          *
 262          * Therefore we must increment the rproc refcount here, and decrement
 263          * it _only_ when the vdev is released.
 264          */
 265         kref_get(&rproc->refcount);
 266
 267         ret = register_virtio_device(vdev);
 268         if (ret) {
 269                 kref_put(&rproc->refcount, rproc_release);
 270                 dev_err(dev, "failed to register vdev: %d\n", ret);
 271                 goto out;
 272         }
 273
 274         dev_info(dev, "registered %s (type %d)\n", dev_name(&vdev->dev), id);
 275
 276 out:
 277         return ret;
 278 }
 279
 280 /**
 281  * rproc_remove_virtio_dev() - remove an rproc-induced virtio device
 282  * @rvdev: the remote vdev
 283  *
 284  * This function unregisters an existing virtio device.
 285  */
 286 void rproc_remove_virtio_dev(struct rproc_vdev *rvdev)
 287 {
 288         unregister_virtio_device(&rvdev->vdev);
 289 }