![Joe Perches](/assets/img/avatar_default.png)
Prefer the direct use of octal for permissions. Done with checkpatch -f --types=SYMBOLIC_PERMS --fix-inplace and some typing. Miscellanea: o Whitespace neatening around these conversions. Signed-off-by: Joe Perches <joe@perches.com> Reviewed-by: Wei Liu <wei.liu2@citrix.com> Signed-off-by: David S. Miller <davem@davemloft.net>
473 lines
11 KiB
C
473 lines
11 KiB
C
/*
|
|
* Copyright (C) ST-Ericsson AB 2010
|
|
* Author: Sjur Brendeland
|
|
* License terms: GNU General Public License (GPL) version 2
|
|
*/
|
|
|
|
#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);
|
|
if (!IS_ERR(ser->debugfs_tty_dir)) {
|
|
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_x32("ser_state", 0400,
|
|
ser->debugfs_tty_dir,
|
|
(u32 *)&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 sk_buff *tmp = skb_dequeue(&ser->head);
|
|
WARN_ON(tmp != skb);
|
|
if (in_interrupt())
|
|
dev_kfree_skb_irq(skb);
|
|
else
|
|
kfree_skb(skb);
|
|
}
|
|
}
|
|
/* Send flow off if queue is empty */
|
|
if (ser->head.qlen <= SEND_QUEUE_LOW &&
|
|
test_and_clear_bit(CAIF_FLOW_OFF_SENT, &ser->state) &&
|
|
ser->common.flowctrl != NULL)
|
|
ser->common.flowctrl(ser->dev, ON);
|
|
clear_bit(CAIF_SENDING, &ser->state);
|
|
return 0;
|
|
error:
|
|
clear_bit(CAIF_SENDING, &ser->state);
|
|
return tty_wr;
|
|
}
|
|
|
|
static int caif_xmit(struct sk_buff *skb, struct net_device *dev)
|
|
{
|
|
struct ser_device *ser;
|
|
|
|
BUG_ON(dev == NULL);
|
|
ser = netdev_priv(dev);
|
|
|
|
/* Send flow off once, on high water mark */
|
|
if (ser->head.qlen > SEND_QUEUE_HIGH &&
|
|
!test_and_set_bit(CAIF_FLOW_OFF_SENT, &ser->state) &&
|
|
ser->common.flowctrl != NULL)
|
|
|
|
ser->common.flowctrl(ser->dev, OFF);
|
|
|
|
skb_queue_tail(&ser->head, skb);
|
|
return handle_tx(ser);
|
|
}
|
|
|
|
|
|
static void ldisc_tx_wakeup(struct tty_struct *tty)
|
|
{
|
|
struct ser_device *ser;
|
|
|
|
ser = tty->disc_data;
|
|
BUG_ON(ser == NULL);
|
|
WARN_ON(ser->tty != tty);
|
|
handle_tx(ser);
|
|
}
|
|
|
|
|
|
static void ser_release(struct work_struct *work)
|
|
{
|
|
struct list_head list;
|
|
struct ser_device *ser, *tmp;
|
|
|
|
spin_lock(&ser_lock);
|
|
list_replace_init(&ser_release_list, &list);
|
|
spin_unlock(&ser_lock);
|
|
|
|
if (!list_empty(&list)) {
|
|
rtnl_lock();
|
|
list_for_each_entry_safe(ser, tmp, &list, node) {
|
|
dev_close(ser->dev);
|
|
unregister_netdevice(ser->dev);
|
|
debugfs_deinit(ser);
|
|
}
|
|
rtnl_unlock();
|
|
}
|
|
}
|
|
|
|
static DECLARE_WORK(ser_release_work, ser_release);
|
|
|
|
static int ldisc_open(struct tty_struct *tty)
|
|
{
|
|
struct ser_device *ser;
|
|
struct net_device *dev;
|
|
char name[64];
|
|
int result;
|
|
|
|
/* No write no play */
|
|
if (tty->ops->write == NULL)
|
|
return -EOPNOTSUPP;
|
|
if (!capable(CAP_SYS_ADMIN) && !capable(CAP_SYS_TTY_CONFIG))
|
|
return -EPERM;
|
|
|
|
/* release devices to avoid name collision */
|
|
ser_release(NULL);
|
|
|
|
result = snprintf(name, sizeof(name), "cf%s", tty->name);
|
|
if (result >= IFNAMSIZ)
|
|
return -EINVAL;
|
|
dev = alloc_netdev(sizeof(*ser), name, NET_NAME_UNKNOWN,
|
|
caifdev_setup);
|
|
if (!dev)
|
|
return -ENOMEM;
|
|
|
|
ser = netdev_priv(dev);
|
|
ser->tty = tty_kref_get(tty);
|
|
ser->dev = dev;
|
|
debugfs_init(ser, tty);
|
|
tty->receive_room = N_TTY_BUF_SIZE;
|
|
tty->disc_data = ser;
|
|
set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
|
|
rtnl_lock();
|
|
result = register_netdevice(dev);
|
|
if (result) {
|
|
rtnl_unlock();
|
|
free_netdev(dev);
|
|
return -ENODEV;
|
|
}
|
|
|
|
spin_lock(&ser_lock);
|
|
list_add(&ser->node, &ser_list);
|
|
spin_unlock(&ser_lock);
|
|
rtnl_unlock();
|
|
netif_stop_queue(dev);
|
|
update_tty_status(ser);
|
|
return 0;
|
|
}
|
|
|
|
static void ldisc_close(struct tty_struct *tty)
|
|
{
|
|
struct ser_device *ser = tty->disc_data;
|
|
|
|
tty_kref_put(ser->tty);
|
|
|
|
spin_lock(&ser_lock);
|
|
list_move(&ser->node, &ser_release_list);
|
|
spin_unlock(&ser_lock);
|
|
schedule_work(&ser_release_work);
|
|
}
|
|
|
|
/* The line discipline structure. */
|
|
static struct tty_ldisc_ops caif_ldisc = {
|
|
.owner = THIS_MODULE,
|
|
.magic = TTY_LDISC_MAGIC,
|
|
.name = "n_caif",
|
|
.open = ldisc_open,
|
|
.close = ldisc_close,
|
|
.receive_buf = ldisc_receive,
|
|
.write_wakeup = ldisc_tx_wakeup
|
|
};
|
|
|
|
static int register_ldisc(void)
|
|
{
|
|
int result;
|
|
|
|
result = tty_register_ldisc(N_CAIF, &caif_ldisc);
|
|
if (result < 0) {
|
|
pr_err("cannot register CAIF ldisc=%d err=%d\n", N_CAIF,
|
|
result);
|
|
return result;
|
|
}
|
|
return result;
|
|
}
|
|
static const struct net_device_ops netdev_ops = {
|
|
.ndo_open = caif_net_open,
|
|
.ndo_stop = caif_net_close,
|
|
.ndo_start_xmit = caif_xmit
|
|
};
|
|
|
|
static void caifdev_setup(struct net_device *dev)
|
|
{
|
|
struct ser_device *serdev = netdev_priv(dev);
|
|
|
|
dev->features = 0;
|
|
dev->netdev_ops = &netdev_ops;
|
|
dev->type = ARPHRD_CAIF;
|
|
dev->flags = IFF_POINTOPOINT | IFF_NOARP;
|
|
dev->mtu = CAIF_MAX_MTU;
|
|
dev->priv_flags |= IFF_NO_QUEUE;
|
|
dev->needs_free_netdev = true;
|
|
skb_queue_head_init(&serdev->head);
|
|
serdev->common.link_select = CAIF_LINK_LOW_LATENCY;
|
|
serdev->common.use_frag = true;
|
|
serdev->common.use_stx = ser_use_stx;
|
|
serdev->common.use_fcs = ser_use_fcs;
|
|
serdev->dev = dev;
|
|
}
|
|
|
|
|
|
static int caif_net_open(struct net_device *dev)
|
|
{
|
|
netif_wake_queue(dev);
|
|
return 0;
|
|
}
|
|
|
|
static int caif_net_close(struct net_device *dev)
|
|
{
|
|
netif_stop_queue(dev);
|
|
return 0;
|
|
}
|
|
|
|
static int __init caif_ser_init(void)
|
|
{
|
|
int ret;
|
|
|
|
ret = register_ldisc();
|
|
debugfsdir = debugfs_create_dir("caif_serial", NULL);
|
|
return ret;
|
|
}
|
|
|
|
static void __exit caif_ser_exit(void)
|
|
{
|
|
spin_lock(&ser_lock);
|
|
list_splice(&ser_list, &ser_release_list);
|
|
spin_unlock(&ser_lock);
|
|
ser_release(NULL);
|
|
cancel_work_sync(&ser_release_work);
|
|
tty_unregister_ldisc(N_CAIF);
|
|
debugfs_remove_recursive(debugfsdir);
|
|
}
|
|
|
|
module_init(caif_ser_init);
|
|
module_exit(caif_ser_exit);
|