1 files changed, 299 insertions, 0 deletions
diff --git a/drivers/remoteproc/remoteproc_virtio.c b/drivers/remoteproc/remoteproc_virtio.c
new file mode 100644
index 00000000000..4f73e811bb8
--- /dev/null
+++ b/drivers/remoteproc/remoteproc_virtio.c
@@ -0,0 +1,299 @@
+/*
+ * 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);
+
+	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);
+}