/*
* Remote processor messaging transport (OMAP platform-specific bits)
*
* Copyright (C) 2011 Texas Instruments, Inc.
* Copyright (C) 2011 Google, Inc.
*
* Ohad Ben-Cohen <ohad@wizery.com>
* Brian Swetland <swetland@google.com>
*
* This software is licensed under the terms of the GNU General Public
* License version 2, as published by the Free Software Foundation, and
* may be copied, distributed, and modified under those terms.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#include <linux/export.h>
#include <linux/remoteproc.h>
#include <linux/rpmsg.h>
#include <linux/virtio.h>
#include <linux/virtio_config.h>
#include <linux/virtio_ids.h>
#include <linux/virtio_ring.h>
#include <linux/err.h>
#include <linux/kref.h>
#include <linux/slab.h>
#include "remoteproc_internal.h"
/**
* struct rproc_virtio_vq_info - virtqueue state
* @vq_id: a unique index of this virtqueue (unique for this @rproc)
* @rproc: handle to the remote processor
*
* Such a struct will be maintained for every virtqueue we're
* using to communicate with the remote processor
*/
struct rproc_virtio_vq_info {
__u16 vq_id;
struct rproc *rproc;
};
/* kick the remote processor, and let it know which virtqueue to poke at */
static void rproc_virtio_notify(struct virtqueue *vq)
{
struct rproc_virtio_vq_info *rpvq = vq->priv;
struct rproc *rproc = rpvq->rproc;
dev_dbg(rproc->dev, "kicking vq id: %d\n", rpvq->vq_id);
rproc->ops->kick(rproc, rpvq->vq_id);
}
/**
* rproc_vq_interrupt() - tell remoteproc that a virtqueue is interrupted
* @rproc: handle to the remote processor
* @vq_id: index of the signalled virtqueue
*
* This function should be called by the platform-specific rproc driver,
* when the remote processor signals that a specific virtqueue has pending
* messages available.
*
* Returns IRQ_NONE if no message was found in the @vq_id virtqueue,
* and otherwise returns IRQ_HANDLED.
*/
irqreturn_t rproc_vq_interrupt(struct rproc *rproc, int vq_id)
{
return vring_interrupt(0, rproc->rvdev->vq[vq_id]);
}
EXPORT_SYMBOL(rproc_vq_interrupt);
static struct virtqueue *rp_find_vq(struct virtio_device *vdev,
unsigned id,
void (*callback)(struct virtqueue *vq),
const char *name)
{
struct rproc *rproc = vdev_to_rproc(vdev);
struct rproc_vdev *rvdev = rproc->rvdev;
struct rproc_virtio_vq_info *rpvq;
struct virtqueue *vq;
void *addr;
int ret, len;
rpvq = kmalloc(sizeof(*rpvq), GFP_KERNEL);
if (!rpvq)
return ERR_PTR(-ENOMEM);
rpvq->rproc = rproc;
rpvq->vq_id = id;
addr = rvdev->vring[id].va;
len = rvdev->vring[id].len;
dev_dbg(rproc->dev, "vring%d: va %p qsz %d\n", id, addr, len);
/*
* Create the new vq, and tell virtio we're not interested in
* the 'weak' smp barriers, since we're talking with a real device.
*/
vq = vring_new_virtqueue(len, AMP_VRING_ALIGN, vdev, false, addr,
rproc_virtio_notify, callback, name);
if (!vq) {
dev_err(rproc->dev, "vring_new_virtqueue %s failed\n", name);
ret = -ENOMEM;
goto free_rpvq;
}
rvdev->vq[id] = vq;
vq->priv = rpvq;
return vq;
free_rpvq:
kfree(rpvq);
return ERR_PTR(ret);
}
static void rproc_virtio_del_vqs(struct virtio_device *vdev)
{
struct virtqueue *vq, *n;
struct rproc *rproc = vdev_to_rproc(vdev);
/* power down the remote processor before deleting vqs */
rproc_shutdown(rproc);
list_for_each_entry_safe(vq, n, &vdev->vqs, list) {
struct rproc_virtio_vq_info *rpvq = vq->priv;
vring_del_virtqueue(vq);
kfree(rpvq);
}
}
static int rproc_virtio_find_vqs(struct virtio_device *vdev, unsigned nvqs,
struct virtqueue *vqs[],
vq_callback_t *callbacks[],
const char *names[])
{
struct rproc *rproc = vdev_to_rproc(vdev);
int i, ret;
/* we maintain two virtqueues per remote processor (for RX and TX) */
if (nvqs != 2)
return -EINVAL;
for (i = 0; i < nvqs; ++i) {
vqs[i] = rp_find_vq(vdev, i, callbacks[i], names[i]);
if (IS_ERR(vqs[i])) {
ret = PTR_ERR(vqs[i]);
goto error;
}
}
/* now that the vqs are all set, boot the remote processor */
ret = rproc_boot(rproc);
if (ret) {
dev_err(rproc->dev, "rproc_boot() failed %d\n", ret);
goto error;
}
return 0;
error:
rproc_virtio_del_vqs(vdev);
return ret;
}
/*
* We don't support yet real virtio status semantics.
*
* The plan is to provide this via the VIRTIO HDR resource entry
* which is part of the firmware: this way the remote processor
* will be able to access the status values as set by us.
*/
static u8 rproc_virtio_get_status(struct virtio_device *vdev)
{
return 0;
}
static void rproc_virtio_set_status(struct virtio_device *vdev, u8 status)
{
dev_dbg(&vdev->dev, "new status: %d\n", status);
}
static void rproc_virtio_reset(struct virtio_device *vdev)
{
dev_dbg(&vdev->dev, "reset !\n");
}
/* provide the vdev features as retrieved from the firmware */
static u32 rproc_virtio_get_features(struct virtio_device *vdev)
{
struct rproc *rproc = vdev_to_rproc(vdev);
/* we only support a single vdev device for now */
return rproc->rvdev->dfeatures;
}
static void rproc_virtio_finalize_features(struct virtio_device *vdev)
{
struct rproc *rproc = vdev_to_rproc(vdev);
/* Give virtio_ring a chance to accept features */
vring_transport_features(vdev);
/*
* Remember the finalized features of our vdev, and provide it
* to the remote processor once it is powered on.
*
* Similarly to the status field, we don't expose yet the negotiated
* features to the remote processors at this point. This will be
* fixed as part of a small resource table overhaul and then an
* extension of the virtio resource entries.
*/
rproc->rvdev->gfeatures = vdev->features[0];
}
static struct virtio_config_ops rproc_virtio_config_ops = {
.get_features = rproc_virtio_get_features,
.finalize_features = rproc_virtio_finalize_features,
.find_vqs = rproc_virtio_find_vqs,
.del_vqs = rproc_virtio_del_vqs,
.reset = rproc_virtio_reset,
.set_status = rproc_virtio_set_status,
.get_status = rproc_virtio_get_status,
};
/*
* This function is called whenever vdev is released, and is responsible
* to decrement the remote processor's refcount taken when vdev was
* added.
*
* Never call this function directly; it will be called by the driver
* core when needed.
*/
static void rproc_vdev_release(struct device *dev)
{
struct virtio_device *vdev = dev_to_virtio(dev);
struct rproc *rproc = vdev_to_rproc(vdev);
kref_put(&rproc->refcount, rproc_release);
}
/**
* rproc_add_rpmsg_vdev() - create an rpmsg virtio device
* @rproc: the rproc handle
*
* This function is called if virtio rpmsg support was found in the
* firmware of the remote processor.
*
* Today we only support creating a single rpmsg vdev (virtio device),
* but the plan is to remove this limitation. At that point this interface
* will be revised/extended.
*/
int rproc_add_rpmsg_vdev(struct rproc *rproc)
{
struct device *dev = rproc->dev;
struct rproc_vdev *rvdev = rproc->rvdev;
int ret;
rvdev->vdev.id.device = VIRTIO_ID_RPMSG,
rvdev->vdev.config = &rproc_virtio_config_ops,
rvdev->vdev.dev.parent = dev;
rvdev->vdev.dev.release = rproc_vdev_release;
/*
* We're indirectly making a non-temporary copy of the rproc pointer
* here, because drivers probed with this vdev will indirectly
* access the wrapping rproc.
*
* Therefore we must increment the rproc refcount here, and decrement
* it _only_ when the vdev is released.
*/
kref_get(&rproc->refcount);
ret = register_virtio_device(&rvdev->vdev);
if (ret) {
kref_put(&rproc->refcount, rproc_release);
dev_err(dev, "failed to register vdev: %d\n", ret);
}
return ret;
}
/**
* rproc_remove_rpmsg_vdev() - remove an rpmsg vdev device
* @rproc: the rproc handle
*
* This function is called whenever @rproc is removed _iff_ an rpmsg
* vdev was created beforehand.
*/
void rproc_remove_rpmsg_vdev(struct rproc *rproc)
{
struct rproc_vdev *rvdev = rproc->rvdev;
unregister_virtio_device(&rvdev->vdev);
}
