1 files changed, 569 insertions, 0 deletions
diff --git a/drivers/rpmsg/rpmsg_char.c b/drivers/rpmsg/rpmsg_char.c
new file mode 100644
index 0000000000..09833ad05d
--- /dev/null
+++ b/drivers/rpmsg/rpmsg_char.c
@@ -0,0 +1,569 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2022, STMicroelectronics
+ * Copyright (c) 2016, Linaro Ltd.
+ * Copyright (c) 2012, Michal Simek <monstr@monstr.eu>
+ * Copyright (c) 2012, PetaLogix
+ * Copyright (c) 2011, Texas Instruments, Inc.
+ * Copyright (c) 2011, Google, Inc.
+ *
+ * Based on rpmsg performance statistics driver by Michal Simek, which in turn
+ * was based on TI & Google OMX rpmsg driver.
+ */
+
+#define pr_fmt(fmt)	KBUILD_MODNAME ": " fmt
+
+#include <linux/cdev.h>
+#include <linux/device.h>
+#include <linux/fs.h>
+#include <linux/idr.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/poll.h>
+#include <linux/rpmsg.h>
+#include <linux/skbuff.h>
+#include <linux/slab.h>
+#include <linux/uaccess.h>
+#include <uapi/linux/rpmsg.h>
+
+#include "rpmsg_char.h"
+#include "rpmsg_internal.h"
+
+#define RPMSG_DEV_MAX	(MINORMASK + 1)
+
+static dev_t rpmsg_major;
+
+static DEFINE_IDA(rpmsg_ept_ida);
+static DEFINE_IDA(rpmsg_minor_ida);
+
+#define dev_to_eptdev(dev) container_of(dev, struct rpmsg_eptdev, dev)
+#define cdev_to_eptdev(i_cdev) container_of(i_cdev, struct rpmsg_eptdev, cdev)
+
+/**
+ * struct rpmsg_eptdev - endpoint device context
+ * @dev:	endpoint device
+ * @cdev:	cdev for the endpoint device
+ * @rpdev:	underlaying rpmsg device
+ * @chinfo:	info used to open the endpoint
+ * @ept_lock:	synchronization of @ept modifications
+ * @ept:	rpmsg endpoint reference, when open
+ * @queue_lock:	synchronization of @queue operations
+ * @queue:	incoming message queue
+ * @readq:	wait object for incoming queue
+ * @default_ept: set to channel default endpoint if the default endpoint should be re-used
+ *              on device open to prevent endpoint address update.
+ * remote_flow_restricted: to indicate if the remote has requested for flow to be limited
+ * remote_flow_updated: to indicate if the flow control has been requested
+ */
+struct rpmsg_eptdev {
+	struct device dev;
+	struct cdev cdev;
+
+	struct rpmsg_device *rpdev;
+	struct rpmsg_channel_info chinfo;
+
+	struct mutex ept_lock;
+	struct rpmsg_endpoint *ept;
+	struct rpmsg_endpoint *default_ept;
+
+	spinlock_t queue_lock;
+	struct sk_buff_head queue;
+	wait_queue_head_t readq;
+
+	bool remote_flow_restricted;
+	bool remote_flow_updated;
+};
+
+int rpmsg_chrdev_eptdev_destroy(struct device *dev, void *data)
+{
+	struct rpmsg_eptdev *eptdev = dev_to_eptdev(dev);
+
+	mutex_lock(&eptdev->ept_lock);
+	eptdev->rpdev = NULL;
+	if (eptdev->ept) {
+		/* The default endpoint is released by the rpmsg core */
+		if (!eptdev->default_ept)
+			rpmsg_destroy_ept(eptdev->ept);
+		eptdev->ept = NULL;
+	}
+	mutex_unlock(&eptdev->ept_lock);
+
+	/* wake up any blocked readers */
+	wake_up_interruptible(&eptdev->readq);
+
+	cdev_device_del(&eptdev->cdev, &eptdev->dev);
+	put_device(&eptdev->dev);
+
+	return 0;
+}
+EXPORT_SYMBOL(rpmsg_chrdev_eptdev_destroy);
+
+static int rpmsg_ept_cb(struct rpmsg_device *rpdev, void *buf, int len,
+			void *priv, u32 addr)
+{
+	struct rpmsg_eptdev *eptdev = priv;
+	struct sk_buff *skb;
+
+	skb = alloc_skb(len, GFP_ATOMIC);
+	if (!skb)
+		return -ENOMEM;
+
+	skb_put_data(skb, buf, len);
+
+	spin_lock(&eptdev->queue_lock);
+	skb_queue_tail(&eptdev->queue, skb);
+	spin_unlock(&eptdev->queue_lock);
+
+	/* wake up any blocking processes, waiting for new data */
+	wake_up_interruptible(&eptdev->readq);
+
+	return 0;
+}
+
+static int rpmsg_ept_flow_cb(struct rpmsg_device *rpdev, void *priv, bool enable)
+{
+	struct rpmsg_eptdev *eptdev = priv;
+
+	eptdev->remote_flow_restricted = enable;
+	eptdev->remote_flow_updated = true;
+
+	wake_up_interruptible(&eptdev->readq);
+
+	return 0;
+}
+
+static int rpmsg_eptdev_open(struct inode *inode, struct file *filp)
+{
+	struct rpmsg_eptdev *eptdev = cdev_to_eptdev(inode->i_cdev);
+	struct rpmsg_endpoint *ept;
+	struct rpmsg_device *rpdev = eptdev->rpdev;
+	struct device *dev = &eptdev->dev;
+
+	mutex_lock(&eptdev->ept_lock);
+	if (eptdev->ept) {
+		mutex_unlock(&eptdev->ept_lock);
+		return -EBUSY;
+	}
+
+	if (!eptdev->rpdev) {
+		mutex_unlock(&eptdev->ept_lock);
+		return -ENETRESET;
+	}
+
+	get_device(dev);
+
+	/*
+	 * If the default_ept is set, the rpmsg device default endpoint is used.
+	 * Else a new endpoint is created on open that will be destroyed on release.
+	 */
+	if (eptdev->default_ept)
+		ept = eptdev->default_ept;
+	else
+		ept = rpmsg_create_ept(rpdev, rpmsg_ept_cb, eptdev, eptdev->chinfo);
+
+	if (!ept) {
+		dev_err(dev, "failed to open %s\n", eptdev->chinfo.name);
+		put_device(dev);
+		mutex_unlock(&eptdev->ept_lock);
+		return -EINVAL;
+	}
+
+	ept->flow_cb = rpmsg_ept_flow_cb;
+	eptdev->ept = ept;
+	filp->private_data = eptdev;
+	mutex_unlock(&eptdev->ept_lock);
+
+	return 0;
+}
+
+static int rpmsg_eptdev_release(struct inode *inode, struct file *filp)
+{
+	struct rpmsg_eptdev *eptdev = cdev_to_eptdev(inode->i_cdev);
+	struct device *dev = &eptdev->dev;
+
+	/* Close the endpoint, if it's not already destroyed by the parent */
+	mutex_lock(&eptdev->ept_lock);
+	if (eptdev->ept) {
+		if (!eptdev->default_ept)
+			rpmsg_destroy_ept(eptdev->ept);
+		eptdev->ept = NULL;
+	}
+	mutex_unlock(&eptdev->ept_lock);
+	eptdev->remote_flow_updated = false;
+
+	/* Discard all SKBs */
+	skb_queue_purge(&eptdev->queue);
+
+	put_device(dev);
+
+	return 0;
+}
+
+static ssize_t rpmsg_eptdev_read_iter(struct kiocb *iocb, struct iov_iter *to)
+{
+	struct file *filp = iocb->ki_filp;
+	struct rpmsg_eptdev *eptdev = filp->private_data;
+	unsigned long flags;
+	struct sk_buff *skb;
+	int use;
+
+	if (!eptdev->ept)
+		return -EPIPE;
+
+	spin_lock_irqsave(&eptdev->queue_lock, flags);
+
+	/* Wait for data in the queue */
+	if (skb_queue_empty(&eptdev->queue)) {
+		spin_unlock_irqrestore(&eptdev->queue_lock, flags);
+
+		if (filp->f_flags & O_NONBLOCK)
+			return -EAGAIN;
+
+		/* Wait until we get data or the endpoint goes away */
+		if (wait_event_interruptible(eptdev->readq,
+					     !skb_queue_empty(&eptdev->queue) ||
+					     !eptdev->ept))
+			return -ERESTARTSYS;
+
+		/* We lost the endpoint while waiting */
+		if (!eptdev->ept)
+			return -EPIPE;
+
+		spin_lock_irqsave(&eptdev->queue_lock, flags);
+	}
+
+	skb = skb_dequeue(&eptdev->queue);
+	spin_unlock_irqrestore(&eptdev->queue_lock, flags);
+	if (!skb)
+		return -EFAULT;
+
+	use = min_t(size_t, iov_iter_count(to), skb->len);
+	if (copy_to_iter(skb->data, use, to) != use)
+		use = -EFAULT;
+
+	kfree_skb(skb);
+
+	return use;
+}
+
+static ssize_t rpmsg_eptdev_write_iter(struct kiocb *iocb,
+				       struct iov_iter *from)
+{
+	struct file *filp = iocb->ki_filp;
+	struct rpmsg_eptdev *eptdev = filp->private_data;
+	size_t len = iov_iter_count(from);
+	void *kbuf;
+	int ret;
+
+	kbuf = kzalloc(len, GFP_KERNEL);
+	if (!kbuf)
+		return -ENOMEM;
+
+	if (!copy_from_iter_full(kbuf, len, from)) {
+		ret = -EFAULT;
+		goto free_kbuf;
+	}
+
+	if (mutex_lock_interruptible(&eptdev->ept_lock)) {
+		ret = -ERESTARTSYS;
+		goto free_kbuf;
+	}
+
+	if (!eptdev->ept) {
+		ret = -EPIPE;
+		goto unlock_eptdev;
+	}
+
+	if (filp->f_flags & O_NONBLOCK) {
+		ret = rpmsg_trysendto(eptdev->ept, kbuf, len, eptdev->chinfo.dst);
+		if (ret == -ENOMEM)
+			ret = -EAGAIN;
+	} else {
+		ret = rpmsg_sendto(eptdev->ept, kbuf, len, eptdev->chinfo.dst);
+	}
+
+unlock_eptdev:
+	mutex_unlock(&eptdev->ept_lock);
+
+free_kbuf:
+	kfree(kbuf);
+	return ret < 0 ? ret : len;
+}
+
+static __poll_t rpmsg_eptdev_poll(struct file *filp, poll_table *wait)
+{
+	struct rpmsg_eptdev *eptdev = filp->private_data;
+	__poll_t mask = 0;
+
+	if (!eptdev->ept)
+		return EPOLLERR;
+
+	poll_wait(filp, &eptdev->readq, wait);
+
+	if (!skb_queue_empty(&eptdev->queue))
+		mask |= EPOLLIN | EPOLLRDNORM;
+
+	if (eptdev->remote_flow_updated)
+		mask |= EPOLLPRI;
+
+	mutex_lock(&eptdev->ept_lock);
+	mask |= rpmsg_poll(eptdev->ept, filp, wait);
+	mutex_unlock(&eptdev->ept_lock);
+
+	return mask;
+}
+
+static long rpmsg_eptdev_ioctl(struct file *fp, unsigned int cmd,
+			       unsigned long arg)
+{
+	struct rpmsg_eptdev *eptdev = fp->private_data;
+
+	bool set;
+	int ret;
+
+	switch (cmd) {
+	case RPMSG_GET_OUTGOING_FLOWCONTROL:
+		eptdev->remote_flow_updated = false;
+		ret = put_user(eptdev->remote_flow_restricted, (int __user *)arg);
+		break;
+	case RPMSG_SET_INCOMING_FLOWCONTROL:
+		if (arg > 1) {
+			ret = -EINVAL;
+			break;
+		}
+		set = !!arg;
+		ret = rpmsg_set_flow_control(eptdev->ept, set, eptdev->chinfo.dst);
+		break;
+	case RPMSG_DESTROY_EPT_IOCTL:
+		/* Don't allow to destroy a default endpoint. */
+		if (eptdev->default_ept) {
+			ret = -EINVAL;
+			break;
+		}
+		ret = rpmsg_chrdev_eptdev_destroy(&eptdev->dev, NULL);
+		break;
+	default:
+		ret = -EINVAL;
+	}
+
+	return ret;
+}
+
+static const struct file_operations rpmsg_eptdev_fops = {
+	.owner = THIS_MODULE,
+	.open = rpmsg_eptdev_open,
+	.release = rpmsg_eptdev_release,
+	.read_iter = rpmsg_eptdev_read_iter,
+	.write_iter = rpmsg_eptdev_write_iter,
+	.poll = rpmsg_eptdev_poll,
+	.unlocked_ioctl = rpmsg_eptdev_ioctl,
+	.compat_ioctl = compat_ptr_ioctl,
+};
+
+static ssize_t name_show(struct device *dev, struct device_attribute *attr,
+			 char *buf)
+{
+	struct rpmsg_eptdev *eptdev = dev_get_drvdata(dev);
+
+	return sprintf(buf, "%s\n", eptdev->chinfo.name);
+}
+static DEVICE_ATTR_RO(name);
+
+static ssize_t src_show(struct device *dev, struct device_attribute *attr,
+			 char *buf)
+{
+	struct rpmsg_eptdev *eptdev = dev_get_drvdata(dev);
+
+	return sprintf(buf, "%d\n", eptdev->chinfo.src);
+}
+static DEVICE_ATTR_RO(src);
+
+static ssize_t dst_show(struct device *dev, struct device_attribute *attr,
+			 char *buf)
+{
+	struct rpmsg_eptdev *eptdev = dev_get_drvdata(dev);
+
+	return sprintf(buf, "%d\n", eptdev->chinfo.dst);
+}
+static DEVICE_ATTR_RO(dst);
+
+static struct attribute *rpmsg_eptdev_attrs[] = {
+	&dev_attr_name.attr,
+	&dev_attr_src.attr,
+	&dev_attr_dst.attr,
+	NULL
+};
+ATTRIBUTE_GROUPS(rpmsg_eptdev);
+
+static void rpmsg_eptdev_release_device(struct device *dev)
+{
+	struct rpmsg_eptdev *eptdev = dev_to_eptdev(dev);
+
+	ida_simple_remove(&rpmsg_ept_ida, dev->id);
+	ida_simple_remove(&rpmsg_minor_ida, MINOR(eptdev->dev.devt));
+	kfree(eptdev);
+}
+
+static struct rpmsg_eptdev *rpmsg_chrdev_eptdev_alloc(struct rpmsg_device *rpdev,
+						      struct device *parent)
+{
+	struct rpmsg_eptdev *eptdev;
+	struct device *dev;
+
+	eptdev = kzalloc(sizeof(*eptdev), GFP_KERNEL);
+	if (!eptdev)
+		return ERR_PTR(-ENOMEM);
+
+	dev = &eptdev->dev;
+	eptdev->rpdev = rpdev;
+
+	mutex_init(&eptdev->ept_lock);
+	spin_lock_init(&eptdev->queue_lock);
+	skb_queue_head_init(&eptdev->queue);
+	init_waitqueue_head(&eptdev->readq);
+
+	device_initialize(dev);
+	dev->class = rpmsg_class;
+	dev->parent = parent;
+	dev->groups = rpmsg_eptdev_groups;
+	dev_set_drvdata(dev, eptdev);
+
+	cdev_init(&eptdev->cdev, &rpmsg_eptdev_fops);
+	eptdev->cdev.owner = THIS_MODULE;
+
+	return eptdev;
+}
+
+static int rpmsg_chrdev_eptdev_add(struct rpmsg_eptdev *eptdev, struct rpmsg_channel_info chinfo)
+{
+	struct device *dev = &eptdev->dev;
+	int ret;
+
+	eptdev->chinfo = chinfo;
+
+	ret = ida_simple_get(&rpmsg_minor_ida, 0, RPMSG_DEV_MAX, GFP_KERNEL);
+	if (ret < 0)
+		goto free_eptdev;
+	dev->devt = MKDEV(MAJOR(rpmsg_major), ret);
+
+	ret = ida_simple_get(&rpmsg_ept_ida, 0, 0, GFP_KERNEL);
+	if (ret < 0)
+		goto free_minor_ida;
+	dev->id = ret;
+	dev_set_name(dev, "rpmsg%d", ret);
+
+	ret = cdev_device_add(&eptdev->cdev, &eptdev->dev);
+	if (ret)
+		goto free_ept_ida;
+
+	/* We can now rely on the release function for cleanup */
+	dev->release = rpmsg_eptdev_release_device;
+
+	return ret;
+
+free_ept_ida:
+	ida_simple_remove(&rpmsg_ept_ida, dev->id);
+free_minor_ida:
+	ida_simple_remove(&rpmsg_minor_ida, MINOR(dev->devt));
+free_eptdev:
+	put_device(dev);
+	kfree(eptdev);
+
+	return ret;
+}
+
+int rpmsg_chrdev_eptdev_create(struct rpmsg_device *rpdev, struct device *parent,
+			       struct rpmsg_channel_info chinfo)
+{
+	struct rpmsg_eptdev *eptdev;
+
+	eptdev = rpmsg_chrdev_eptdev_alloc(rpdev, parent);
+	if (IS_ERR(eptdev))
+		return PTR_ERR(eptdev);
+
+	return rpmsg_chrdev_eptdev_add(eptdev, chinfo);
+}
+EXPORT_SYMBOL(rpmsg_chrdev_eptdev_create);
+
+static int rpmsg_chrdev_probe(struct rpmsg_device *rpdev)
+{
+	struct rpmsg_channel_info chinfo;
+	struct rpmsg_eptdev *eptdev;
+	struct device *dev = &rpdev->dev;
+
+	memcpy(chinfo.name, rpdev->id.name, RPMSG_NAME_SIZE);
+	chinfo.src = rpdev->src;
+	chinfo.dst = rpdev->dst;
+
+	eptdev = rpmsg_chrdev_eptdev_alloc(rpdev, dev);
+	if (IS_ERR(eptdev))
+		return PTR_ERR(eptdev);
+
+	/* Set the default_ept to the rpmsg device endpoint */
+	eptdev->default_ept = rpdev->ept;
+
+	/*
+	 * The rpmsg_ept_cb uses *priv parameter to get its rpmsg_eptdev context.
+	 * Storedit in default_ept *priv field.
+	 */
+	eptdev->default_ept->priv = eptdev;
+
+	return rpmsg_chrdev_eptdev_add(eptdev, chinfo);
+}
+
+static void rpmsg_chrdev_remove(struct rpmsg_device *rpdev)
+{
+	int ret;
+
+	ret = device_for_each_child(&rpdev->dev, NULL, rpmsg_chrdev_eptdev_destroy);
+	if (ret)
+		dev_warn(&rpdev->dev, "failed to destroy endpoints: %d\n", ret);
+}
+
+static struct rpmsg_device_id rpmsg_chrdev_id_table[] = {
+	{ .name	= "rpmsg-raw" },
+	{ },
+};
+
+static struct rpmsg_driver rpmsg_chrdev_driver = {
+	.probe = rpmsg_chrdev_probe,
+	.remove = rpmsg_chrdev_remove,
+	.callback = rpmsg_ept_cb,
+	.id_table = rpmsg_chrdev_id_table,
+	.drv.name = "rpmsg_chrdev",
+};
+
+static int rpmsg_chrdev_init(void)
+{
+	int ret;
+
+	ret = alloc_chrdev_region(&rpmsg_major, 0, RPMSG_DEV_MAX, "rpmsg_char");
+	if (ret < 0) {
+		pr_err("failed to allocate char dev region\n");
+		return ret;
+	}
+
+	ret = register_rpmsg_driver(&rpmsg_chrdev_driver);
+	if (ret < 0) {
+		pr_err("rpmsg: failed to register rpmsg raw driver\n");
+		goto free_region;
+	}
+
+	return 0;
+
+free_region:
+	unregister_chrdev_region(rpmsg_major, RPMSG_DEV_MAX);
+
+	return ret;
+}
+postcore_initcall(rpmsg_chrdev_init);
+
+static void rpmsg_chrdev_exit(void)
+{
+	unregister_rpmsg_driver(&rpmsg_chrdev_driver);
+	unregister_chrdev_region(rpmsg_major, RPMSG_DEV_MAX);
+}
+module_exit(rpmsg_chrdev_exit);
+
+MODULE_ALIAS("rpmsg:rpmsg_chrdev");
+MODULE_LICENSE("GPL v2");