1 files changed, 350 insertions, 0 deletions
diff --git a/drivers/remoteproc/remoteproc_virtio.c b/drivers/remoteproc/remoteproc_virtio.c
new file mode 100644
index 000000000..bbecd44df
--- /dev/null
+++ b/drivers/remoteproc/remoteproc_virtio.c
@@ -0,0 +1,350 @@
+/*
+ * 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/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"
+
+/* kick the remote processor, and let it know which virtqueue to poke at */
+static bool rproc_virtio_notify(struct virtqueue *vq)
+{
+	struct rproc_vring *rvring = vq->priv;
+	struct rproc *rproc = rvring->rvdev->rproc;
+	int notifyid = rvring->notifyid;
+
+	dev_dbg(&rproc->dev, "kicking vq index: %d\n", notifyid);
+
+	rproc->ops->kick(rproc, notifyid);
+	return true;
+}
+
+/**
+ * rproc_vq_interrupt() - tell remoteproc that a virtqueue is interrupted
+ * @rproc: handle to the remote processor
+ * @notifyid: index of the signalled virtqueue (unique per this @rproc)
+ *
+ * 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 @notifyid virtqueue,
+ * and otherwise returns IRQ_HANDLED.
+ */
+irqreturn_t rproc_vq_interrupt(struct rproc *rproc, int notifyid)
+{
+	struct rproc_vring *rvring;
+
+	dev_dbg(&rproc->dev, "vq index %d is interrupted\n", notifyid);
+
+	rvring = idr_find(&rproc->notifyids, notifyid);
+	if (!rvring || !rvring->vq)
+		return IRQ_NONE;
+
+	return vring_interrupt(0, rvring->vq);
+}
+EXPORT_SYMBOL(rproc_vq_interrupt);
+
+static struct virtqueue *rp_find_vq(struct virtio_device *vdev,
+				    unsigned int id,
+				    void (*callback)(struct virtqueue *vq),
+				    const char *name, bool ctx)
+{
+	struct rproc_vdev *rvdev = vdev_to_rvdev(vdev);
+	struct rproc *rproc = vdev_to_rproc(vdev);
+	struct device *dev = &rproc->dev;
+	struct rproc_vring *rvring;
+	struct virtqueue *vq;
+	void *addr;
+	int len, size;
+
+	/* we're temporarily limited to two virtqueues per rvdev */
+	if (id >= ARRAY_SIZE(rvdev->vring))
+		return ERR_PTR(-EINVAL);
+
+	if (!name)
+		return NULL;
+
+	rvring = &rvdev->vring[id];
+	addr = rvring->va;
+	len = rvring->len;
+
+	/* zero vring */
+	size = vring_size(len, rvring->align);
+	memset(addr, 0, size);
+
+	dev_dbg(dev, "vring%d: va %pK qsz %d notifyid %d\n",
+		id, addr, len, rvring->notifyid);
+
+	/*
+	 * 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(id, len, rvring->align, vdev, false, ctx,
+				 addr, rproc_virtio_notify, callback, name);
+	if (!vq) {
+		dev_err(dev, "vring_new_virtqueue %s failed\n", name);
+		rproc_free_vring(rvring);
+		return ERR_PTR(-ENOMEM);
+	}
+
+	rvring->vq = vq;
+	vq->priv = rvring;
+
+	return vq;
+}
+
+static void __rproc_virtio_del_vqs(struct virtio_device *vdev)
+{
+	struct virtqueue *vq, *n;
+	struct rproc_vring *rvring;
+
+	list_for_each_entry_safe(vq, n, &vdev->vqs, list) {
+		rvring = vq->priv;
+		rvring->vq = NULL;
+		vring_del_virtqueue(vq);
+	}
+}
+
+static void rproc_virtio_del_vqs(struct virtio_device *vdev)
+{
+	__rproc_virtio_del_vqs(vdev);
+}
+
+static int rproc_virtio_find_vqs(struct virtio_device *vdev, unsigned int nvqs,
+				 struct virtqueue *vqs[],
+				 vq_callback_t *callbacks[],
+				 const char * const names[],
+				 const bool * ctx,
+				 struct irq_affinity *desc)
+{
+	int i, ret;
+
+	for (i = 0; i < nvqs; ++i) {
+		vqs[i] = rp_find_vq(vdev, i, callbacks[i], names[i],
+				    ctx ? ctx[i] : false);
+		if (IS_ERR(vqs[i])) {
+			ret = PTR_ERR(vqs[i]);
+			goto error;
+		}
+	}
+
+	return 0;
+
+error:
+	__rproc_virtio_del_vqs(vdev);
+	return ret;
+}
+
+static u8 rproc_virtio_get_status(struct virtio_device *vdev)
+{
+	struct rproc_vdev *rvdev = vdev_to_rvdev(vdev);
+	struct fw_rsc_vdev *rsc;
+
+	rsc = (void *)rvdev->rproc->table_ptr + rvdev->rsc_offset;
+
+	return rsc->status;
+}
+
+static void rproc_virtio_set_status(struct virtio_device *vdev, u8 status)
+{
+	struct rproc_vdev *rvdev = vdev_to_rvdev(vdev);
+	struct fw_rsc_vdev *rsc;
+
+	rsc = (void *)rvdev->rproc->table_ptr + rvdev->rsc_offset;
+
+	rsc->status = status;
+	dev_dbg(&vdev->dev, "status: %d\n", status);
+}
+
+static void rproc_virtio_reset(struct virtio_device *vdev)
+{
+	struct rproc_vdev *rvdev = vdev_to_rvdev(vdev);
+	struct fw_rsc_vdev *rsc;
+
+	rsc = (void *)rvdev->rproc->table_ptr + rvdev->rsc_offset;
+
+	rsc->status = 0;
+	dev_dbg(&vdev->dev, "reset !\n");
+}
+
+/* provide the vdev features as retrieved from the firmware */
+static u64 rproc_virtio_get_features(struct virtio_device *vdev)
+{
+	struct rproc_vdev *rvdev = vdev_to_rvdev(vdev);
+	struct fw_rsc_vdev *rsc;
+
+	rsc = (void *)rvdev->rproc->table_ptr + rvdev->rsc_offset;
+
+	return rsc->dfeatures;
+}
+
+static int rproc_virtio_finalize_features(struct virtio_device *vdev)
+{
+	struct rproc_vdev *rvdev = vdev_to_rvdev(vdev);
+	struct fw_rsc_vdev *rsc;
+
+	rsc = (void *)rvdev->rproc->table_ptr + rvdev->rsc_offset;
+
+	/* Give virtio_ring a chance to accept features */
+	vring_transport_features(vdev);
+
+	/* Make sure we don't have any features > 32 bits! */
+	BUG_ON((u32)vdev->features != vdev->features);
+
+	/*
+	 * Remember the finalized features of our vdev, and provide it
+	 * to the remote processor once it is powered on.
+	 */
+	rsc->gfeatures = vdev->features;
+
+	return 0;
+}
+
+static void rproc_virtio_get(struct virtio_device *vdev, unsigned int offset,
+			     void *buf, unsigned int len)
+{
+	struct rproc_vdev *rvdev = vdev_to_rvdev(vdev);
+	struct fw_rsc_vdev *rsc;
+	void *cfg;
+
+	rsc = (void *)rvdev->rproc->table_ptr + rvdev->rsc_offset;
+	cfg = &rsc->vring[rsc->num_of_vrings];
+
+	if (offset + len > rsc->config_len || offset + len < len) {
+		dev_err(&vdev->dev, "rproc_virtio_get: access out of bounds\n");
+		return;
+	}
+
+	memcpy(buf, cfg + offset, len);
+}
+
+static void rproc_virtio_set(struct virtio_device *vdev, unsigned int offset,
+			     const void *buf, unsigned int len)
+{
+	struct rproc_vdev *rvdev = vdev_to_rvdev(vdev);
+	struct fw_rsc_vdev *rsc;
+	void *cfg;
+
+	rsc = (void *)rvdev->rproc->table_ptr + rvdev->rsc_offset;
+	cfg = &rsc->vring[rsc->num_of_vrings];
+
+	if (offset + len > rsc->config_len || offset + len < len) {
+		dev_err(&vdev->dev, "rproc_virtio_set: access out of bounds\n");
+		return;
+	}
+
+	memcpy(cfg + offset, buf, len);
+}
+
+static const 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,
+	.get		= rproc_virtio_get,
+	.set		= rproc_virtio_set,
+};
+
+/*
+ * This function is called whenever vdev is released, and is responsible
+ * to decrement the remote processor's refcount which was taken when vdev was
+ * added.
+ *
+ * Never call this function directly; it will be called by the driver
+ * core when needed.
+ */
+static void rproc_virtio_dev_release(struct device *dev)
+{
+	struct virtio_device *vdev = dev_to_virtio(dev);
+	struct rproc_vdev *rvdev = vdev_to_rvdev(vdev);
+	struct rproc *rproc = vdev_to_rproc(vdev);
+
+	kref_put(&rvdev->refcount, rproc_vdev_release);
+
+	put_device(&rproc->dev);
+}
+
+/**
+ * rproc_add_virtio_dev() - register an rproc-induced virtio device
+ * @rvdev: the remote vdev
+ *
+ * This function registers a virtio device. This vdev's partent is
+ * the rproc device.
+ *
+ * Returns 0 on success or an appropriate error value otherwise.
+ */
+int rproc_add_virtio_dev(struct rproc_vdev *rvdev, int id)
+{
+	struct rproc *rproc = rvdev->rproc;
+	struct device *dev = &rproc->dev;
+	struct virtio_device *vdev = &rvdev->vdev;
+	int ret;
+
+	vdev->id.device	= id,
+	vdev->config = &rproc_virtio_config_ops,
+	vdev->dev.parent = dev;
+	vdev->dev.release = rproc_virtio_dev_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.
+	 */
+	get_device(&rproc->dev);
+
+	/* Reference the vdev and vring allocations */
+	kref_get(&rvdev->refcount);
+
+	ret = register_virtio_device(vdev);
+	if (ret) {
+		put_device(&vdev->dev);
+		dev_err(dev, "failed to register vdev: %d\n", ret);
+		goto out;
+	}
+
+	dev_info(dev, "registered %s (type %d)\n", dev_name(&vdev->dev), id);
+
+out:
+	return ret;
+}
+
+/**
+ * rproc_remove_virtio_dev() - remove an rproc-induced virtio device
+ * @rvdev: the remote vdev
+ *
+ * This function unregisters an existing virtio device.
+ */
+void rproc_remove_virtio_dev(struct rproc_vdev *rvdev)
+{
+	unregister_virtio_device(&rvdev->vdev);
+}