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// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (C) ST-Ericsson AB 2010
* Author: Sjur Brendeland
*/
#include <linux/hardirq.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/device.h>
#include <linux/types.h>
#include <linux/skbuff.h>
#include <linux/netdevice.h>
#include <linux/rtnetlink.h>
#include <linux/tty.h>
#include <linux/file.h>
#include <linux/if_arp.h>
#include <net/caif/caif_device.h>
#include <net/caif/cfcnfg.h>
#include <linux/err.h>
#include <linux/debugfs.h>
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Sjur Brendeland");
MODULE_DESCRIPTION("CAIF serial device TTY line discipline");
MODULE_LICENSE("GPL");
MODULE_ALIAS_LDISC(N_CAIF);
#define SEND_QUEUE_LOW 10
#define SEND_QUEUE_HIGH 100
#define CAIF_SENDING 1 /* Bit 1 = 0x02*/
#define CAIF_FLOW_OFF_SENT 4 /* Bit 4 = 0x10 */
#define MAX_WRITE_CHUNK 4096
#define ON 1
#define OFF 0
#define CAIF_MAX_MTU 4096
static DEFINE_SPINLOCK(ser_lock);
static LIST_HEAD(ser_list);
static LIST_HEAD(ser_release_list);
static bool ser_loop;
module_param(ser_loop, bool, 0444);
MODULE_PARM_DESC(ser_loop, "Run in simulated loopback mode.");
static bool ser_use_stx = true;
module_param(ser_use_stx, bool, 0444);
MODULE_PARM_DESC(ser_use_stx, "STX enabled or not.");
static bool ser_use_fcs = true;
module_param(ser_use_fcs, bool, 0444);
MODULE_PARM_DESC(ser_use_fcs, "FCS enabled or not.");
static int ser_write_chunk = MAX_WRITE_CHUNK;
module_param(ser_write_chunk, int, 0444);
MODULE_PARM_DESC(ser_write_chunk, "Maximum size of data written to UART.");
static struct dentry *debugfsdir;
static int caif_net_open(struct net_device *dev);
static int caif_net_close(struct net_device *dev);
struct ser_device {
struct caif_dev_common common;
struct list_head node;
struct net_device *dev;
struct sk_buff_head head;
struct tty_struct *tty;
bool tx_started;
unsigned long state;
#ifdef CONFIG_DEBUG_FS
struct dentry *debugfs_tty_dir;
struct debugfs_blob_wrapper tx_blob;
struct debugfs_blob_wrapper rx_blob;
u8 rx_data[128];
u8 tx_data[128];
u8 tty_status;
#endif
};
static void caifdev_setup(struct net_device *dev);
static void ldisc_tx_wakeup(struct tty_struct *tty);
#ifdef CONFIG_DEBUG_FS
static inline void update_tty_status(struct ser_device *ser)
{
ser->tty_status =
ser->tty->stopped << 5 |
ser->tty->flow_stopped << 3 |
ser->tty->packet << 2 |
ser->tty->port->low_latency << 1;
}
static inline void debugfs_init(struct ser_device *ser, struct tty_struct *tty)
{
ser->debugfs_tty_dir = debugfs_create_dir(tty->name, debugfsdir);
debugfs_create_blob("last_tx_msg", 0400, ser->debugfs_tty_dir,
&ser->tx_blob);
debugfs_create_blob("last_rx_msg", 0400, ser->debugfs_tty_dir,
&ser->rx_blob);
debugfs_create_xul("ser_state", 0400, ser->debugfs_tty_dir,
&ser->state);
debugfs_create_x8("tty_status", 0400, ser->debugfs_tty_dir,
&ser->tty_status);
ser->tx_blob.data = ser->tx_data;
ser->tx_blob.size = 0;
ser->rx_blob.data = ser->rx_data;
ser->rx_blob.size = 0;
}
static inline void debugfs_deinit(struct ser_device *ser)
{
debugfs_remove_recursive(ser->debugfs_tty_dir);
}
static inline void debugfs_rx(struct ser_device *ser, const u8 *data, int size)
{
if (size > sizeof(ser->rx_data))
size = sizeof(ser->rx_data);
memcpy(ser->rx_data, data, size);
ser->rx_blob.data = ser->rx_data;
ser->rx_blob.size = size;
}
static inline void debugfs_tx(struct ser_device *ser, const u8 *data, int size)
{
if (size > sizeof(ser->tx_data))
size = sizeof(ser->tx_data);
memcpy(ser->tx_data, data, size);
ser->tx_blob.data = ser->tx_data;
ser->tx_blob.size = size;
}
#else
static inline void debugfs_init(struct ser_device *ser, struct tty_struct *tty)
{
}
static inline void debugfs_deinit(struct ser_device *ser)
{
}
static inline void update_tty_status(struct ser_device *ser)
{
}
static inline void debugfs_rx(struct ser_device *ser, const u8 *data, int size)
{
}
static inline void debugfs_tx(struct ser_device *ser, const u8 *data, int size)
{
}
#endif
static void ldisc_receive(struct tty_struct *tty, const u8 *data,
char *flags, int count)
{
struct sk_buff *skb = NULL;
struct ser_device *ser;
int ret;
ser = tty->disc_data;
/*
* NOTE: flags may contain information about break or overrun.
* This is not yet handled.
*/
/*
* Workaround for garbage at start of transmission,
* only enable if STX handling is not enabled.
*/
if (!ser->common.use_stx && !ser->tx_started) {
dev_info(&ser->dev->dev,
"Bytes received before initial transmission -"
"bytes discarded.\n");
return;
}
BUG_ON(ser->dev == NULL);
/* Get a suitable caif packet and copy in data. */
skb = netdev_alloc_skb(ser->dev, count+1);
if (skb == NULL)
return;
skb_put_data(skb, data, count);
skb->protocol = htons(ETH_P_CAIF);
skb_reset_mac_header(skb);
debugfs_rx(ser, data, count);
/* Push received packet up the stack. */
ret = netif_rx_ni(skb);
if (!ret) {
ser->dev->stats.rx_packets++;
ser->dev->stats.rx_bytes += count;
} else
++ser->dev->stats.rx_dropped;
update_tty_status(ser);
}
static int handle_tx(struct ser_device *ser)
{
struct tty_struct *tty;
struct sk_buff *skb;
int tty_wr, len, room;
tty = ser->tty;
ser->tx_started = true;
/* Enter critical section */
if (test_and_set_bit(CAIF_SENDING, &ser->state))
return 0;
/* skb_peek is safe because handle_tx is called after skb_queue_tail */
while ((skb = skb_peek(&ser->head)) != NULL) {
/* Make sure you don't write too much */
len = skb->len;
room = tty_write_room(tty);
if (!room)
break;
if (room > ser_write_chunk)
room = ser_write_chunk;
if (len > room)
len = room;
/* Write to tty or loopback */
if (!ser_loop) {
tty_wr = tty->ops->write(tty, skb->data, len);
update_tty_status(ser);
} else {
tty_wr = len;
ldisc_receive(tty, skb->data, NULL, len);
}
ser->dev->stats.tx_packets++;
ser->dev->stats.tx_bytes += tty_wr;
/* Error on TTY ?! */
if (tty_wr < 0)
goto error;
/* Reduce buffer written, and discard if empty */
skb_pull(skb, tty_wr);
if (skb->len == 0) {
struct
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