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 device *dev = &rproc->dev;
  78         struct rproc_vring *rvring;
  79         struct virtqueue *vq;
  80         void *addr;
  81         int len, size, ret;
  82
  83         /* we're temporarily limited to two virtqueues per rvdev */
  84         if (id >= ARRAY_SIZE(rvdev->vring))
  85                 return ERR_PTR(-EINVAL);
  86
  87         ret = rproc_alloc_vring(rvdev, id);
  88         if (ret)
  89                 return ERR_PTR(ret);
  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(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 *rproc = vdev_to_rproc(vdev);
 124         struct rproc_vring *rvring;
 125
 126         /* power down the remote processor before deleting vqs */
 127         rproc_shutdown(rproc);
 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 int rproc_virtio_find_vqs(struct virtio_device *vdev, unsigned nvqs,
 138                        struct virtqueue *vqs[],
 139                        vq_callback_t *callbacks[],
 140                        const char *names[])
 141 {
 142         struct rproc *rproc = vdev_to_rproc(vdev);
 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         /* now that the vqs are all set, boot the remote processor */
 154         ret = rproc_boot(rproc);
 155         if (ret) {
 156                 dev_err(&rproc->dev, "rproc_boot() failed %d\n", ret);
 157                 goto error;
 158         }
 159
 160         return 0;
 161
 162 error:
 163         rproc_virtio_del_vqs(vdev);
 164         return ret;
 165 }
 166
 167 /*
 168  * We don't support yet real virtio status semantics.
 169  *
 170  * The plan is to provide this via the VDEV resource entry
 171  * which is part of the firmware: this way the remote processor
 172  * will be able to access the status values as set by us.
 173  */
 174 static u8 rproc_virtio_get_status(struct virtio_device *vdev)
 175 {
 176         return 0;
 177 }
 178
 179 static void rproc_virtio_set_status(struct virtio_device *vdev, u8 status)
 180 {
 181         dev_dbg(&vdev->dev, "status: %d\n", status);
 182 }
 183
 184 static void rproc_virtio_reset(struct virtio_device *vdev)
 185 {
 186         dev_dbg(&vdev->dev, "reset !\n");
 187 }
 188
 189 /* provide the vdev features as retrieved from the firmware */
 190 static u32 rproc_virtio_get_features(struct virtio_device *vdev)
 191 {
 192         struct rproc_vdev *rvdev = vdev_to_rvdev(vdev);
 193
 194         return rvdev->dfeatures;
 195 }
 196
 197 static void rproc_virtio_finalize_features(struct virtio_device *vdev)
 198 {
 199         struct rproc_vdev *rvdev = vdev_to_rvdev(vdev);
 200
 201         /* Give virtio_ring a chance to accept features */
 202         vring_transport_features(vdev);
 203
 204         /*
 205          * Remember the finalized features of our vdev, and provide it
 206          * to the remote processor once it is powered on.
 207          *
 208          * Similarly to the status field, we don't expose yet the negotiated
 209          * features to the remote processors at this point. This will be
 210          * fixed as part of a small resource table overhaul and then an
 211          * extension of the virtio resource entries.
 212          */
 213         rvdev->gfeatures = vdev->features[0];
 214 }
 215
 216 static struct virtio_config_ops rproc_virtio_config_ops = {
 217         .get_features   = rproc_virtio_get_features,
 218         .finalize_features = rproc_virtio_finalize_features,
 219         .find_vqs       = rproc_virtio_find_vqs,
 220         .del_vqs        = rproc_virtio_del_vqs,
 221         .reset          = rproc_virtio_reset,
 222         .set_status     = rproc_virtio_set_status,
 223         .get_status     = rproc_virtio_get_status,
 224 };
 225
 226 /*
 227  * This function is called whenever vdev is released, and is responsible
 228  * to decrement the remote processor's refcount which was taken when vdev was
 229  * added.
 230  *
 231  * Never call this function directly; it will be called by the driver
 232  * core when needed.
 233  */
 234 static void rproc_vdev_release(struct device *dev)
 235 {
 236         struct virtio_device *vdev = dev_to_virtio(dev);
 237         struct rproc_vdev *rvdev = vdev_to_rvdev(vdev);
 238         struct rproc *rproc = vdev_to_rproc(vdev);
 239
 240         list_del(&rvdev->node);
 241         kfree(rvdev);
 242
 243         put_device(&rproc->dev);
 244 }
 245
 246 /**
 247  * rproc_add_virtio_dev() - register an rproc-induced virtio device
 248  * @rvdev: the remote vdev
 249  *
 250  * This function registers a virtio device. This vdev's partent is
 251  * the rproc device.
 252  *
 253  * Returns 0 on success or an appropriate error value otherwise.
 254  */
 255 int rproc_add_virtio_dev(struct rproc_vdev *rvdev, int id)
 256 {
 257         struct rproc *rproc = rvdev->rproc;
 258         struct device *dev = &rproc->dev;
 259         struct virtio_device *vdev = &rvdev->vdev;
 260         int ret;
 261
 262         vdev->id.device = id,
 263         vdev->config = &rproc_virtio_config_ops,
 264         vdev->dev.parent = dev;
 265         vdev->dev.release = rproc_vdev_release;
 266
 267         /*
 268          * We're indirectly making a non-temporary copy of the rproc pointer
 269          * here, because drivers probed with this vdev will indirectly
 270          * access the wrapping rproc.
 271          *
 272          * Therefore we must increment the rproc refcount here, and decrement
 273          * it _only_ when the vdev is released.
 274          */
 275         get_device(&rproc->dev);
 276
 277         ret = register_virtio_device(vdev);
 278         if (ret) {
 279                 put_device(&rproc->dev);
 280                 dev_err(dev, "failed to register vdev: %d\n", ret);
 281                 goto out;
 282         }
 283
 284         dev_info(dev, "registered %s (type %d)\n", dev_name(&vdev->dev), id);
 285
 286 out:
 287         return ret;
 288 }
 289
 290 /**
 291  * rproc_remove_virtio_dev() - remove an rproc-induced virtio device
 292  * @rvdev: the remote vdev
 293  *
 294  * This function unregisters an existing virtio device.
 295  */
 296 void rproc_remove_virtio_dev(struct rproc_vdev *rvdev)
 297 {
 298         unregister_virtio_device(&rvdev->vdev);
 299 }