remoteproc: create rpmsg virtio device

obj-$(CONFIG_REMOTEPROC)		+= remoteproc.o

remoteproc-y				:= remoteproc_core.o

remoteproc-y				+= remoteproc_debugfs.o

remoteproc-y				+= remoteproc_rpmsg.o

/*

 * 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);

	vq = vring_new_virtqueue(len, AMP_VRING_ALIGN, vdev, 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);

	list_for_each_entry_safe(vq, n, &vdev->vqs, list) {

		struct rproc_virtio_vq_info *rpvq = vq->priv;

		vring_del_virtqueue(vq);

		kfree(rpvq);

	}

	/* power down the remote processor */

	rproc_shutdown(rproc);

}

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;

	/* boot the remote processor */

	ret = rproc_boot(rproc);

	if (ret) {

		dev_err(rproc->dev, "rproc_boot() failed %d\n", ret);

		goto error;

	}

	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;

		}

	}

	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);

}