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-rw-r--r--drivers/rpmsg/rpmsg_char.c569
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");