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         if (!name)
  88                 return NULL;
  89
  90         ret = rproc_alloc_vring(rvdev, id);
  91         if (ret)
  92                 return ERR_PTR(ret);
  93
  94         rvring = &rvdev->vring[id];
  95         addr = rvring->va;
  96         len = rvring->len;
  97
  98         /* zero vring */
  99         size = vring_size(len, rvring->align);
 100         memset(addr, 0, size);
 101
 102         dev_dbg(dev, "vring%d: va %p qsz %d notifyid %d\n",
 103                                         id, addr, len, rvring->notifyid);
 104
 105         /*
 106          * Create the new vq, and tell virtio we're not interested in
 107          * the 'weak' smp barriers, since we're talking with a real device.
 108          */
 109         vq = vring_new_virtqueue(id, len, rvring->align, vdev, false, addr,
 110                                         rproc_virtio_notify, callback, name);
 111         if (!vq) {
 112                 dev_err(dev, "vring_new_virtqueue %s failed\n", name);
 113                 rproc_free_vring(rvring);
 114                 return ERR_PTR(-ENOMEM);
 115         }
 116
 117         rvring->vq = vq;
 118         vq->priv = rvring;
 119
 120         return vq;
 121 }
 122
 123 static void __rproc_virtio_del_vqs(struct virtio_device *vdev)
 124 {
 125         struct virtqueue *vq, *n;
 126         struct rproc_vring *rvring;
 127
 128         list_for_each_entry_safe(vq, n, &vdev->vqs, list) {
 129                 rvring = vq->priv;
 130                 rvring->vq = NULL;
 131                 vring_del_virtqueue(vq);
 132                 rproc_free_vring(rvring);
 133         }
 134 }
 135
 136 static void rproc_virtio_del_vqs(struct virtio_device *vdev)
 137 {
 138         struct rproc *rproc = vdev_to_rproc(vdev);
 139
 140         /* power down the remote processor before deleting vqs */
 141         rproc_shutdown(rproc);
 142
 143         __rproc_virtio_del_vqs(vdev);
 144 }
 145
 146 static int rproc_virtio_find_vqs(struct virtio_device *vdev, unsigned nvqs,
 147                        struct virtqueue *vqs[],
 148                        vq_callback_t *callbacks[],
 149                        const char *names[])
 150 {
 151         struct rproc *rproc = vdev_to_rproc(vdev);
 152         int i, ret;
 153
 154         for (i = 0; i < nvqs; ++i) {
 155                 vqs[i] = rp_find_vq(vdev, i, callbacks[i], names[i]);
 156                 if (IS_ERR(vqs[i])) {
 157                         ret = PTR_ERR(vqs[i]);
 158                         goto error;
 159                 }
 160         }
 161
 162         /* now that the vqs are all set, boot the remote processor */
 163         ret = rproc_boot(rproc);
 164         if (ret) {
 165                 dev_err(&rproc->dev, "rproc_boot() failed %d\n", ret);
 166                 goto error;
 167         }
 168
 169         return 0;
 170
 171 error:
 172         __rproc_virtio_del_vqs(vdev);
 173         return ret;
 174 }
 175
 176 /*
 177  * We don't support yet real virtio status semantics.
 178  *
 179  * The plan is to provide this via the VDEV resource entry
 180  * which is part of the firmware: this way the remote processor
 181  * will be able to access the status values as set by us.
 182  */
 183 static u8 rproc_virtio_get_status(struct virtio_device *vdev)
 184 {
 185         return 0;
 186 }
 187
 188 static void rproc_virtio_set_status(struct virtio_device *vdev, u8 status)
 189 {
 190         dev_dbg(&vdev->dev, "status: %d\n", status);
 191 }
 192
 193 static void rproc_virtio_reset(struct virtio_device *vdev)
 194 {
 195         dev_dbg(&vdev->dev, "reset !\n");
 196 }
 197
 198 /* provide the vdev features as retrieved from the firmware */
 199 static u32 rproc_virtio_get_features(struct virtio_device *vdev)
 200 {
 201         struct rproc_vdev *rvdev = vdev_to_rvdev(vdev);
 202
 203         return rvdev->dfeatures;
 204 }
 205
 206 static void rproc_virtio_finalize_features(struct virtio_device *vdev)
 207 {
 208         struct rproc_vdev *rvdev = vdev_to_rvdev(vdev);
 209
 210         /* Give virtio_ring a chance to accept features */
 211         vring_transport_features(vdev);
 212
 213         /*
 214          * Remember the finalized features of our vdev, and provide it
 215          * to the remote processor once it is powered on.
 216          *
 217          * Similarly to the status field, we don't expose yet the negotiated
 218          * features to the remote processors at this point. This will be
 219          * fixed as part of a small resource table overhaul and then an
 220          * extension of the virtio resource entries.
 221          */
 222         rvdev->gfeatures = vdev->features[0];
 223 }
 224
 225 static struct virtio_config_ops rproc_virtio_config_ops = {
 226         .get_features   = rproc_virtio_get_features,
 227         .finalize_features = rproc_virtio_finalize_features,
 228         .find_vqs       = rproc_virtio_find_vqs,
 229         .del_vqs        = rproc_virtio_del_vqs,
 230         .reset          = rproc_virtio_reset,
 231         .set_status     = rproc_virtio_set_status,
 232         .get_status     = rproc_virtio_get_status,
 233 };
 234
 235 /*
 236  * This function is called whenever vdev is released, and is responsible
 237  * to decrement the remote processor's refcount which was taken when vdev was
 238  * added.
 239  *
 240  * Never call this function directly; it will be called by the driver
 241  * core when needed.
 242  */
 243 static void rproc_vdev_release(struct device *dev)
 244 {
 245         struct virtio_device *vdev = dev_to_virtio(dev);
 246         struct rproc_vdev *rvdev = vdev_to_rvdev(vdev);
 247         struct rproc *rproc = vdev_to_rproc(vdev);
 248
 249         list_del(&rvdev->node);
 250         kfree(rvdev);
 251
 252         put_device(&rproc->dev);
 253 }
 254
 255 /**
 256  * rproc_add_virtio_dev() - register an rproc-induced virtio device
 257  * @rvdev: the remote vdev
 258  *
 259  * This function registers a virtio device. This vdev's partent is
 260  * the rproc device.
 261  *
 262  * Returns 0 on success or an appropriate error value otherwise.
 263  */
 264 int rproc_add_virtio_dev(struct rproc_vdev *rvdev, int id)
 265 {
 266         struct rproc *rproc = rvdev->rproc;
 267         struct device *dev = &rproc->dev;
 268         struct virtio_device *vdev = &rvdev->vdev;
 269         int ret;
 270
 271         vdev->id.device = id,
 272         vdev->config = &rproc_virtio_config_ops,
 273         vdev->dev.parent = dev;
 274         vdev->dev.release = rproc_vdev_release;
 275
 276         /*
 277          * We're indirectly making a non-temporary copy of the rproc pointer
 278          * here, because drivers probed with this vdev will indirectly
 279          * access the wrapping rproc.
 280          *
 281          * Therefore we must increment the rproc refcount here, and decrement
 282          * it _only_ when the vdev is released.
 283          */
 284         get_device(&rproc->dev);
 285
 286         ret = register_virtio_device(vdev);
 287         if (ret) {
 288                 put_device(&rproc->dev);
 289                 dev_err(dev, "failed to register vdev: %d\n", ret);
 290                 goto out;
 291         }
 292
 293         dev_info(dev, "registered %s (type %d)\n", dev_name(&vdev->dev), id);
 294
 295 out:
 296         return ret;
 297 }
 298
 299 /**
 300  * rproc_remove_virtio_dev() - remove an rproc-induced virtio device
 301  * @rvdev: the remote vdev
 302  *
 303  * This function unregisters an existing virtio device.
 304  */
 305 void rproc_remove_virtio_dev(struct rproc_vdev *rvdev)
 306 {
 307         unregister_virtio_device(&rvdev->vdev);
 308 }