// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) 2022, STMicroelectronics
* Copyright (c) 2016, Linaro Ltd.
* Copyright (c) 2012, Michal Simek <[email protected]>
* 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_free(&rpmsg_ept_ida, dev->id);
ida_free(&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_alloc_max(&rpmsg_minor_ida, RPMSG_DEV_MAX - 1, GFP_KERNEL);
if (ret < 0)
goto free_eptdev;
dev->devt = MKDEV(MAJOR(rpmsg_major), ret);
ret = ida_alloc(&rpmsg_ept_ida, 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_free(&rpmsg_ept_ida, dev->id);
free_minor_ida:
ida_free(&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_DESCRIPTION("RPMSG device interface");
MODULE_LICENSE("GPL v2");
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