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// SPDX-License-Identifier: GPL-2.0+
//
// Samsung IPC v4.x misc device userspace
// interface.
//
// Copyright (C) 2018 Simon Shields <simon@lineageos.org>
//
#include <dt-bindings/net/samsung_ipc.h>
#include <linux/fs.h>
#include <linux/miscdevice.h>
#include <linux/poll.h>
#include <linux/sipc.h>
#include <linux/skbuff.h>
#include "sipc.h"
static int sipc_get_header(struct sipc_io_channel *chan, union sipc_header *hdr, size_t len)
{
switch (chan->format) {
case SAMSUNG_IPC_FORMAT_FMT:
hdr->fmt.len = len + sizeof(struct fmt_header);
hdr->fmt.control = 0;
return sizeof(struct fmt_header);
case SAMSUNG_IPC_FORMAT_RAW:
case SAMSUNG_IPC_FORMAT_MULTI_RAW:
hdr->raw.len = len + sizeof(struct raw_header);
hdr->raw.channel = chan->channel & 0x1f;
hdr->raw.control = 0;
return sizeof(struct raw_header);
case SAMSUNG_IPC_FORMAT_RFS:
hdr->rfs.len = len + sizeof(struct rfs_header);
hdr->rfs.id = chan->channel;
return sizeof(struct rfs_header);
default:
return 0;
}
return 0;
}
static int sipc_misc_open(struct inode *inode, struct file *filp)
{
struct sipc_io_channel *chan = misc_to_chan(filp->private_data);
int ret;
if (!cur_links[chan->format])
return -ENODEV;
ret = cur_links[chan->format]->open(cur_links[chan->format], chan->channel, chan->format);
if (ret < 0) {
dev_err(chan->sipc->dev, "Failed to open communication: %d\n", ret);
return ret;
}
atomic_inc(&chan->use_count);
return 0;
}
static int sipc_misc_release(struct inode *inode, struct file *filp)
{
struct sipc_io_channel *chan = misc_to_chan(filp->private_data);
atomic_dec(&chan->use_count);
skb_queue_purge(&chan->rx_queue);
return 0;
}
static unsigned int sipc_misc_poll(struct file *filp, struct poll_table_struct *wait)
{
struct sipc_io_channel *chan = misc_to_chan(filp->private_data);
poll_wait(filp, &chan->wq, wait);
if (!skb_queue_empty(&chan->rx_queue))
return POLLIN | POLLRDNORM;
return 0;
}
static ssize_t sipc_misc_write(struct file *filp, const char __user *buf,
size_t count, loff_t *ppos)
{
struct sipc_io_channel *chan = misc_to_chan(filp->private_data);
struct sk_buff *skb;
union sipc_header hdr;
unsigned char *data;
int frame_len, header_size, tx_size, ret;
header_size = sipc_get_header_size(chan->format);
frame_len = sizeof(HDLC_START) + header_size
+ count + sizeof(HDLC_END);
skb = alloc_skb(frame_len, GFP_KERNEL);
if (!skb) {
dev_err(chan->sipc->dev, "Failed to allocate skb\n");
return -ENOMEM;
}
if (chan->format != SAMSUNG_IPC_FORMAT_RAMDUMP) {
data = skb_put(skb, sizeof(HDLC_START));
data[0] = HDLC_START;
/* RFS header is sent separately, as needs to be untouched */
if (chan->format != SAMSUNG_IPC_FORMAT_RFS) {
header_size = sipc_get_header(chan, &hdr, count);
memcpy(skb_put(skb, header_size), &hdr, header_size);
}
}
if (copy_from_user(skb_put(skb, count), buf, count) != 0) {
dev_kfree_skb_any(skb);
return -EFAULT;
}
if (chan->format != SAMSUNG_IPC_FORMAT_RAMDUMP) {
data = skb_put(skb, sizeof(HDLC_END));
data[0] = HDLC_END;
};
switch (chan->format) {
case SAMSUNG_IPC_FORMAT_FMT:
skb_queue_tail(&chan->sipc->tx_queue_fmt, skb);
break;
case SAMSUNG_IPC_FORMAT_RFS:
skb_queue_tail(&chan->sipc->tx_queue_rfs, skb);
break;
case SAMSUNG_IPC_FORMAT_RAW:
skb_queue_tail(&chan->sipc->tx_queue_raw, skb);
break;
default:
dev_err(chan->sipc->dev, "Don't know how to tx format %d\n", chan->format);
}
queue_delayed_work(chan->sipc->tx_wq, &chan->sipc->tx_work, msecs_to_jiffies(5));
return count;
}
static ssize_t sipc_misc_read(struct file *filp, char *buf, size_t count,
loff_t *f_pos)
{
struct sipc_io_channel *chan = misc_to_chan(filp->private_data);
struct sk_buff *skb;
int pktsize;
skb = skb_dequeue(&chan->rx_queue);
if (!skb) {
dev_info(chan->sipc->dev, "No pending RX data\n");
return 0;
}
if (skb->len > count) {
dev_err(chan->sipc->dev, "Read buffer not big enough for whole packet (%d)\n", skb->len);
dev_kfree_skb_any(skb);
return -EFAULT;
}
pktsize = skb->len;
if (copy_to_user(buf, skb->data, pktsize) != 0) {
dev_kfree_skb_any(skb);
return -EFAULT;
}
dev_kfree_skb_any(skb);
return pktsize;
}
const struct file_operations sipc_misc_fops = {
.owner = THIS_MODULE,
.open = sipc_misc_open,
.release = sipc_misc_release,
.poll = sipc_misc_poll,
//.unlocked_ioctl = sipc_misc_ioctl,
.write = sipc_misc_write,
.read = sipc_misc_read,
};
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