/*
|
* slcan.c - serial line CAN interface driver (using tty line discipline)
|
*
|
* This file is derived from linux/drivers/net/slip/slip.c
|
*
|
* slip.c Authors : Laurence Culhane <loz@holmes.demon.co.uk>
|
* Fred N. van Kempen <waltje@uwalt.nl.mugnet.org>
|
* slcan.c Author : Oliver Hartkopp <socketcan@hartkopp.net>
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by the
|
* Free Software Foundation; either version 2 of the License, or (at your
|
* option) any later version.
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*
|
* This program is distributed in the hope that it will be useful, but
|
* WITHOUT ANY WARRANTY; without even the implied warranty of
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
|
* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License along
|
* with this program; if not, see http://www.gnu.org/licenses/gpl.html
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
|
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
|
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
|
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
|
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
|
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
|
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
|
* DAMAGE.
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*
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*/
|
|
#include <linux/module.h>
|
#include <linux/moduleparam.h>
|
|
#include <linux/uaccess.h>
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#include <linux/bitops.h>
|
#include <linux/string.h>
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#include <linux/tty.h>
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#include <linux/errno.h>
|
#include <linux/netdevice.h>
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#include <linux/skbuff.h>
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#include <linux/rtnetlink.h>
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#include <linux/if_arp.h>
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#include <linux/if_ether.h>
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#include <linux/sched.h>
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#include <linux/delay.h>
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#include <linux/init.h>
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#include <linux/kernel.h>
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#include <linux/workqueue.h>
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#include <linux/can.h>
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#include <linux/can/skb.h>
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|
MODULE_ALIAS_LDISC(N_SLCAN);
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MODULE_DESCRIPTION("serial line CAN interface");
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MODULE_LICENSE("GPL");
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MODULE_AUTHOR("Oliver Hartkopp <socketcan@hartkopp.net>");
|
|
#define SLCAN_MAGIC 0x53CA
|
|
static int maxdev = 10; /* MAX number of SLCAN channels;
|
This can be overridden with
|
insmod slcan.ko maxdev=nnn */
|
module_param(maxdev, int, 0);
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MODULE_PARM_DESC(maxdev, "Maximum number of slcan interfaces");
|
|
/* maximum rx buffer len: extended CAN frame with timestamp */
|
#define SLC_MTU (sizeof("T1111222281122334455667788EA5F\r")+1)
|
|
#define SLC_CMD_LEN 1
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#define SLC_SFF_ID_LEN 3
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#define SLC_EFF_ID_LEN 8
|
|
struct slcan {
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int magic;
|
|
/* Various fields. */
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struct tty_struct *tty; /* ptr to TTY structure */
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struct net_device *dev; /* easy for intr handling */
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spinlock_t lock;
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struct work_struct tx_work; /* Flushes transmit buffer */
|
|
/* These are pointers to the malloc()ed frame buffers. */
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unsigned char rbuff[SLC_MTU]; /* receiver buffer */
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int rcount; /* received chars counter */
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unsigned char xbuff[SLC_MTU]; /* transmitter buffer */
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unsigned char *xhead; /* pointer to next XMIT byte */
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int xleft; /* bytes left in XMIT queue */
|
|
unsigned long flags; /* Flag values/ mode etc */
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#define SLF_INUSE 0 /* Channel in use */
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#define SLF_ERROR 1 /* Parity, etc. error */
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};
|
|
static struct net_device **slcan_devs;
|
|
/************************************************************************
|
* SLCAN ENCAPSULATION FORMAT *
|
************************************************************************/
|
|
/*
|
* A CAN frame has a can_id (11 bit standard frame format OR 29 bit extended
|
* frame format) a data length code (can_dlc) which can be from 0 to 8
|
* and up to <can_dlc> data bytes as payload.
|
* Additionally a CAN frame may become a remote transmission frame if the
|
* RTR-bit is set. This causes another ECU to send a CAN frame with the
|
* given can_id.
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*
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* The SLCAN ASCII representation of these different frame types is:
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* <type> <id> <dlc> <data>*
|
*
|
* Extended frames (29 bit) are defined by capital characters in the type.
|
* RTR frames are defined as 'r' types - normal frames have 't' type:
|
* t => 11 bit data frame
|
* r => 11 bit RTR frame
|
* T => 29 bit data frame
|
* R => 29 bit RTR frame
|
*
|
* The <id> is 3 (standard) or 8 (extended) bytes in ASCII Hex (base64).
|
* The <dlc> is a one byte ASCII number ('0' - '8')
|
* The <data> section has at much ASCII Hex bytes as defined by the <dlc>
|
*
|
* Examples:
|
*
|
* t1230 : can_id 0x123, can_dlc 0, no data
|
* t4563112233 : can_id 0x456, can_dlc 3, data 0x11 0x22 0x33
|
* T12ABCDEF2AA55 : extended can_id 0x12ABCDEF, can_dlc 2, data 0xAA 0x55
|
* r1230 : can_id 0x123, can_dlc 0, no data, remote transmission request
|
*
|
*/
|
|
/************************************************************************
|
* STANDARD SLCAN DECAPSULATION *
|
************************************************************************/
|
|
/* Send one completely decapsulated can_frame to the network layer */
|
static void slc_bump(struct slcan *sl)
|
{
|
struct sk_buff *skb;
|
struct can_frame cf;
|
int i, tmp;
|
u32 tmpid;
|
char *cmd = sl->rbuff;
|
|
memset(&cf, 0, sizeof(cf));
|
|
switch (*cmd) {
|
case 'r':
|
cf.can_id = CAN_RTR_FLAG;
|
/* fallthrough */
|
case 't':
|
/* store dlc ASCII value and terminate SFF CAN ID string */
|
cf.can_dlc = sl->rbuff[SLC_CMD_LEN + SLC_SFF_ID_LEN];
|
sl->rbuff[SLC_CMD_LEN + SLC_SFF_ID_LEN] = 0;
|
/* point to payload data behind the dlc */
|
cmd += SLC_CMD_LEN + SLC_SFF_ID_LEN + 1;
|
break;
|
case 'R':
|
cf.can_id = CAN_RTR_FLAG;
|
/* fallthrough */
|
case 'T':
|
cf.can_id |= CAN_EFF_FLAG;
|
/* store dlc ASCII value and terminate EFF CAN ID string */
|
cf.can_dlc = sl->rbuff[SLC_CMD_LEN + SLC_EFF_ID_LEN];
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sl->rbuff[SLC_CMD_LEN + SLC_EFF_ID_LEN] = 0;
|
/* point to payload data behind the dlc */
|
cmd += SLC_CMD_LEN + SLC_EFF_ID_LEN + 1;
|
break;
|
default:
|
return;
|
}
|
|
if (kstrtou32(sl->rbuff + SLC_CMD_LEN, 16, &tmpid))
|
return;
|
|
cf.can_id |= tmpid;
|
|
/* get can_dlc from sanitized ASCII value */
|
if (cf.can_dlc >= '0' && cf.can_dlc < '9')
|
cf.can_dlc -= '0';
|
else
|
return;
|
|
/* RTR frames may have a dlc > 0 but they never have any data bytes */
|
if (!(cf.can_id & CAN_RTR_FLAG)) {
|
for (i = 0; i < cf.can_dlc; i++) {
|
tmp = hex_to_bin(*cmd++);
|
if (tmp < 0)
|
return;
|
cf.data[i] = (tmp << 4);
|
tmp = hex_to_bin(*cmd++);
|
if (tmp < 0)
|
return;
|
cf.data[i] |= tmp;
|
}
|
}
|
|
skb = dev_alloc_skb(sizeof(struct can_frame) +
|
sizeof(struct can_skb_priv));
|
if (!skb)
|
return;
|
|
skb->dev = sl->dev;
|
skb->protocol = htons(ETH_P_CAN);
|
skb->pkt_type = PACKET_BROADCAST;
|
skb->ip_summed = CHECKSUM_UNNECESSARY;
|
|
can_skb_reserve(skb);
|
can_skb_prv(skb)->ifindex = sl->dev->ifindex;
|
can_skb_prv(skb)->skbcnt = 0;
|
|
skb_put_data(skb, &cf, sizeof(struct can_frame));
|
|
sl->dev->stats.rx_packets++;
|
sl->dev->stats.rx_bytes += cf.can_dlc;
|
netif_rx_ni(skb);
|
}
|
|
/* parse tty input stream */
|
static void slcan_unesc(struct slcan *sl, unsigned char s)
|
{
|
if ((s == '\r') || (s == '\a')) { /* CR or BEL ends the pdu */
|
if (!test_and_clear_bit(SLF_ERROR, &sl->flags) &&
|
(sl->rcount > 4)) {
|
slc_bump(sl);
|
}
|
sl->rcount = 0;
|
} else {
|
if (!test_bit(SLF_ERROR, &sl->flags)) {
|
if (sl->rcount < SLC_MTU) {
|
sl->rbuff[sl->rcount++] = s;
|
return;
|
} else {
|
sl->dev->stats.rx_over_errors++;
|
set_bit(SLF_ERROR, &sl->flags);
|
}
|
}
|
}
|
}
|
|
/************************************************************************
|
* STANDARD SLCAN ENCAPSULATION *
|
************************************************************************/
|
|
/* Encapsulate one can_frame and stuff into a TTY queue. */
|
static void slc_encaps(struct slcan *sl, struct can_frame *cf)
|
{
|
int actual, i;
|
unsigned char *pos;
|
unsigned char *endpos;
|
canid_t id = cf->can_id;
|
|
pos = sl->xbuff;
|
|
if (cf->can_id & CAN_RTR_FLAG)
|
*pos = 'R'; /* becomes 'r' in standard frame format (SFF) */
|
else
|
*pos = 'T'; /* becomes 't' in standard frame format (SSF) */
|
|
/* determine number of chars for the CAN-identifier */
|
if (cf->can_id & CAN_EFF_FLAG) {
|
id &= CAN_EFF_MASK;
|
endpos = pos + SLC_EFF_ID_LEN;
|
} else {
|
*pos |= 0x20; /* convert R/T to lower case for SFF */
|
id &= CAN_SFF_MASK;
|
endpos = pos + SLC_SFF_ID_LEN;
|
}
|
|
/* build 3 (SFF) or 8 (EFF) digit CAN identifier */
|
pos++;
|
while (endpos >= pos) {
|
*endpos-- = hex_asc_upper[id & 0xf];
|
id >>= 4;
|
}
|
|
pos += (cf->can_id & CAN_EFF_FLAG) ? SLC_EFF_ID_LEN : SLC_SFF_ID_LEN;
|
|
*pos++ = cf->can_dlc + '0';
|
|
/* RTR frames may have a dlc > 0 but they never have any data bytes */
|
if (!(cf->can_id & CAN_RTR_FLAG)) {
|
for (i = 0; i < cf->can_dlc; i++)
|
pos = hex_byte_pack_upper(pos, cf->data[i]);
|
}
|
|
*pos++ = '\r';
|
|
/* Order of next two lines is *very* important.
|
* When we are sending a little amount of data,
|
* the transfer may be completed inside the ops->write()
|
* routine, because it's running with interrupts enabled.
|
* In this case we *never* got WRITE_WAKEUP event,
|
* if we did not request it before write operation.
|
* 14 Oct 1994 Dmitry Gorodchanin.
|
*/
|
set_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags);
|
actual = sl->tty->ops->write(sl->tty, sl->xbuff, pos - sl->xbuff);
|
sl->xleft = (pos - sl->xbuff) - actual;
|
sl->xhead = sl->xbuff + actual;
|
sl->dev->stats.tx_bytes += cf->can_dlc;
|
}
|
|
/* Write out any remaining transmit buffer. Scheduled when tty is writable */
|
static void slcan_transmit(struct work_struct *work)
|
{
|
struct slcan *sl = container_of(work, struct slcan, tx_work);
|
int actual;
|
|
spin_lock_bh(&sl->lock);
|
/* First make sure we're connected. */
|
if (!sl->tty || sl->magic != SLCAN_MAGIC || !netif_running(sl->dev)) {
|
spin_unlock_bh(&sl->lock);
|
return;
|
}
|
|
if (sl->xleft <= 0) {
|
/* Now serial buffer is almost free & we can start
|
* transmission of another packet */
|
sl->dev->stats.tx_packets++;
|
clear_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags);
|
spin_unlock_bh(&sl->lock);
|
netif_wake_queue(sl->dev);
|
return;
|
}
|
|
actual = sl->tty->ops->write(sl->tty, sl->xhead, sl->xleft);
|
sl->xleft -= actual;
|
sl->xhead += actual;
|
spin_unlock_bh(&sl->lock);
|
}
|
|
/*
|
* Called by the driver when there's room for more data.
|
* Schedule the transmit.
|
*/
|
static void slcan_write_wakeup(struct tty_struct *tty)
|
{
|
struct slcan *sl;
|
|
rcu_read_lock();
|
sl = rcu_dereference(tty->disc_data);
|
if (!sl)
|
goto out;
|
|
schedule_work(&sl->tx_work);
|
out:
|
rcu_read_unlock();
|
}
|
|
/* Send a can_frame to a TTY queue. */
|
static netdev_tx_t slc_xmit(struct sk_buff *skb, struct net_device *dev)
|
{
|
struct slcan *sl = netdev_priv(dev);
|
|
if (skb->len != CAN_MTU)
|
goto out;
|
|
spin_lock(&sl->lock);
|
if (!netif_running(dev)) {
|
spin_unlock(&sl->lock);
|
printk(KERN_WARNING "%s: xmit: iface is down\n", dev->name);
|
goto out;
|
}
|
if (sl->tty == NULL) {
|
spin_unlock(&sl->lock);
|
goto out;
|
}
|
|
netif_stop_queue(sl->dev);
|
slc_encaps(sl, (struct can_frame *) skb->data); /* encaps & send */
|
spin_unlock(&sl->lock);
|
|
out:
|
kfree_skb(skb);
|
return NETDEV_TX_OK;
|
}
|
|
|
/******************************************
|
* Routines looking at netdevice side.
|
******************************************/
|
|
/* Netdevice UP -> DOWN routine */
|
static int slc_close(struct net_device *dev)
|
{
|
struct slcan *sl = netdev_priv(dev);
|
|
spin_lock_bh(&sl->lock);
|
if (sl->tty) {
|
/* TTY discipline is running. */
|
clear_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags);
|
}
|
netif_stop_queue(dev);
|
sl->rcount = 0;
|
sl->xleft = 0;
|
spin_unlock_bh(&sl->lock);
|
|
return 0;
|
}
|
|
/* Netdevice DOWN -> UP routine */
|
static int slc_open(struct net_device *dev)
|
{
|
struct slcan *sl = netdev_priv(dev);
|
|
if (sl->tty == NULL)
|
return -ENODEV;
|
|
sl->flags &= (1 << SLF_INUSE);
|
netif_start_queue(dev);
|
return 0;
|
}
|
|
/* Hook the destructor so we can free slcan devs at the right point in time */
|
static void slc_free_netdev(struct net_device *dev)
|
{
|
int i = dev->base_addr;
|
|
slcan_devs[i] = NULL;
|
}
|
|
static int slcan_change_mtu(struct net_device *dev, int new_mtu)
|
{
|
return -EINVAL;
|
}
|
|
static const struct net_device_ops slc_netdev_ops = {
|
.ndo_open = slc_open,
|
.ndo_stop = slc_close,
|
.ndo_start_xmit = slc_xmit,
|
.ndo_change_mtu = slcan_change_mtu,
|
};
|
|
static void slc_setup(struct net_device *dev)
|
{
|
dev->netdev_ops = &slc_netdev_ops;
|
dev->needs_free_netdev = true;
|
dev->priv_destructor = slc_free_netdev;
|
|
dev->hard_header_len = 0;
|
dev->addr_len = 0;
|
dev->tx_queue_len = 10;
|
|
dev->mtu = CAN_MTU;
|
dev->type = ARPHRD_CAN;
|
|
/* New-style flags. */
|
dev->flags = IFF_NOARP;
|
dev->features = NETIF_F_HW_CSUM;
|
}
|
|
/******************************************
|
Routines looking at TTY side.
|
******************************************/
|
|
/*
|
* Handle the 'receiver data ready' interrupt.
|
* This function is called by the 'tty_io' module in the kernel when
|
* a block of SLCAN data has been received, which can now be decapsulated
|
* and sent on to some IP layer for further processing. This will not
|
* be re-entered while running but other ldisc functions may be called
|
* in parallel
|
*/
|
|
static void slcan_receive_buf(struct tty_struct *tty,
|
const unsigned char *cp, char *fp, int count)
|
{
|
struct slcan *sl = (struct slcan *) tty->disc_data;
|
|
if (!sl || sl->magic != SLCAN_MAGIC || !netif_running(sl->dev))
|
return;
|
|
/* Read the characters out of the buffer */
|
while (count--) {
|
if (fp && *fp++) {
|
if (!test_and_set_bit(SLF_ERROR, &sl->flags))
|
sl->dev->stats.rx_errors++;
|
cp++;
|
continue;
|
}
|
slcan_unesc(sl, *cp++);
|
}
|
}
|
|
/************************************
|
* slcan_open helper routines.
|
************************************/
|
|
/* Collect hanged up channels */
|
static void slc_sync(void)
|
{
|
int i;
|
struct net_device *dev;
|
struct slcan *sl;
|
|
for (i = 0; i < maxdev; i++) {
|
dev = slcan_devs[i];
|
if (dev == NULL)
|
break;
|
|
sl = netdev_priv(dev);
|
if (sl->tty)
|
continue;
|
if (dev->flags & IFF_UP)
|
dev_close(dev);
|
}
|
}
|
|
/* Find a free SLCAN channel, and link in this `tty' line. */
|
static struct slcan *slc_alloc(void)
|
{
|
int i;
|
char name[IFNAMSIZ];
|
struct net_device *dev = NULL;
|
struct slcan *sl;
|
|
for (i = 0; i < maxdev; i++) {
|
dev = slcan_devs[i];
|
if (dev == NULL)
|
break;
|
|
}
|
|
/* Sorry, too many, all slots in use */
|
if (i >= maxdev)
|
return NULL;
|
|
sprintf(name, "slcan%d", i);
|
dev = alloc_netdev(sizeof(*sl), name, NET_NAME_UNKNOWN, slc_setup);
|
if (!dev)
|
return NULL;
|
|
dev->base_addr = i;
|
sl = netdev_priv(dev);
|
|
/* Initialize channel control data */
|
sl->magic = SLCAN_MAGIC;
|
sl->dev = dev;
|
spin_lock_init(&sl->lock);
|
INIT_WORK(&sl->tx_work, slcan_transmit);
|
slcan_devs[i] = dev;
|
|
return sl;
|
}
|
|
/*
|
* Open the high-level part of the SLCAN channel.
|
* This function is called by the TTY module when the
|
* SLCAN line discipline is called for. Because we are
|
* sure the tty line exists, we only have to link it to
|
* a free SLCAN channel...
|
*
|
* Called in process context serialized from other ldisc calls.
|
*/
|
|
static int slcan_open(struct tty_struct *tty)
|
{
|
struct slcan *sl;
|
int err;
|
|
if (!capable(CAP_NET_ADMIN))
|
return -EPERM;
|
|
if (tty->ops->write == NULL)
|
return -EOPNOTSUPP;
|
|
/* RTnetlink lock is misused here to serialize concurrent
|
opens of slcan channels. There are better ways, but it is
|
the simplest one.
|
*/
|
rtnl_lock();
|
|
/* Collect hanged up channels. */
|
slc_sync();
|
|
sl = tty->disc_data;
|
|
err = -EEXIST;
|
/* First make sure we're not already connected. */
|
if (sl && sl->magic == SLCAN_MAGIC)
|
goto err_exit;
|
|
/* OK. Find a free SLCAN channel to use. */
|
err = -ENFILE;
|
sl = slc_alloc();
|
if (sl == NULL)
|
goto err_exit;
|
|
sl->tty = tty;
|
tty->disc_data = sl;
|
|
if (!test_bit(SLF_INUSE, &sl->flags)) {
|
/* Perform the low-level SLCAN initialization. */
|
sl->rcount = 0;
|
sl->xleft = 0;
|
|
set_bit(SLF_INUSE, &sl->flags);
|
|
err = register_netdevice(sl->dev);
|
if (err)
|
goto err_free_chan;
|
}
|
|
/* Done. We have linked the TTY line to a channel. */
|
rtnl_unlock();
|
tty->receive_room = 65536; /* We don't flow control */
|
|
/* TTY layer expects 0 on success */
|
return 0;
|
|
err_free_chan:
|
sl->tty = NULL;
|
tty->disc_data = NULL;
|
clear_bit(SLF_INUSE, &sl->flags);
|
slc_free_netdev(sl->dev);
|
/* do not call free_netdev before rtnl_unlock */
|
rtnl_unlock();
|
free_netdev(sl->dev);
|
return err;
|
|
err_exit:
|
rtnl_unlock();
|
|
/* Count references from TTY module */
|
return err;
|
}
|
|
/*
|
* Close down a SLCAN channel.
|
* This means flushing out any pending queues, and then returning. This
|
* call is serialized against other ldisc functions.
|
*
|
* We also use this method for a hangup event.
|
*/
|
|
static void slcan_close(struct tty_struct *tty)
|
{
|
struct slcan *sl = (struct slcan *) tty->disc_data;
|
|
/* First make sure we're connected. */
|
if (!sl || sl->magic != SLCAN_MAGIC || sl->tty != tty)
|
return;
|
|
spin_lock_bh(&sl->lock);
|
rcu_assign_pointer(tty->disc_data, NULL);
|
sl->tty = NULL;
|
spin_unlock_bh(&sl->lock);
|
|
synchronize_rcu();
|
flush_work(&sl->tx_work);
|
|
/* Flush network side */
|
unregister_netdev(sl->dev);
|
/* This will complete via sl_free_netdev */
|
}
|
|
static int slcan_hangup(struct tty_struct *tty)
|
{
|
slcan_close(tty);
|
return 0;
|
}
|
|
/* Perform I/O control on an active SLCAN channel. */
|
static int slcan_ioctl(struct tty_struct *tty, struct file *file,
|
unsigned int cmd, unsigned long arg)
|
{
|
struct slcan *sl = (struct slcan *) tty->disc_data;
|
unsigned int tmp;
|
|
/* First make sure we're connected. */
|
if (!sl || sl->magic != SLCAN_MAGIC)
|
return -EINVAL;
|
|
switch (cmd) {
|
case SIOCGIFNAME:
|
tmp = strlen(sl->dev->name) + 1;
|
if (copy_to_user((void __user *)arg, sl->dev->name, tmp))
|
return -EFAULT;
|
return 0;
|
|
case SIOCSIFHWADDR:
|
return -EINVAL;
|
|
default:
|
return tty_mode_ioctl(tty, file, cmd, arg);
|
}
|
}
|
|
static struct tty_ldisc_ops slc_ldisc = {
|
.owner = THIS_MODULE,
|
.magic = TTY_LDISC_MAGIC,
|
.name = "slcan",
|
.open = slcan_open,
|
.close = slcan_close,
|
.hangup = slcan_hangup,
|
.ioctl = slcan_ioctl,
|
.receive_buf = slcan_receive_buf,
|
.write_wakeup = slcan_write_wakeup,
|
};
|
|
static int __init slcan_init(void)
|
{
|
int status;
|
|
if (maxdev < 4)
|
maxdev = 4; /* Sanity */
|
|
pr_info("slcan: serial line CAN interface driver\n");
|
pr_info("slcan: %d dynamic interface channels.\n", maxdev);
|
|
slcan_devs = kcalloc(maxdev, sizeof(struct net_device *), GFP_KERNEL);
|
if (!slcan_devs)
|
return -ENOMEM;
|
|
/* Fill in our line protocol discipline, and register it */
|
status = tty_register_ldisc(N_SLCAN, &slc_ldisc);
|
if (status) {
|
printk(KERN_ERR "slcan: can't register line discipline\n");
|
kfree(slcan_devs);
|
}
|
return status;
|
}
|
|
static void __exit slcan_exit(void)
|
{
|
int i;
|
struct net_device *dev;
|
struct slcan *sl;
|
unsigned long timeout = jiffies + HZ;
|
int busy = 0;
|
|
if (slcan_devs == NULL)
|
return;
|
|
/* First of all: check for active disciplines and hangup them.
|
*/
|
do {
|
if (busy)
|
msleep_interruptible(100);
|
|
busy = 0;
|
for (i = 0; i < maxdev; i++) {
|
dev = slcan_devs[i];
|
if (!dev)
|
continue;
|
sl = netdev_priv(dev);
|
spin_lock_bh(&sl->lock);
|
if (sl->tty) {
|
busy++;
|
tty_hangup(sl->tty);
|
}
|
spin_unlock_bh(&sl->lock);
|
}
|
} while (busy && time_before(jiffies, timeout));
|
|
/* FIXME: hangup is async so we should wait when doing this second
|
phase */
|
|
for (i = 0; i < maxdev; i++) {
|
dev = slcan_devs[i];
|
if (!dev)
|
continue;
|
slcan_devs[i] = NULL;
|
|
sl = netdev_priv(dev);
|
if (sl->tty) {
|
printk(KERN_ERR "%s: tty discipline still running\n",
|
dev->name);
|
}
|
|
unregister_netdev(dev);
|
}
|
|
kfree(slcan_devs);
|
slcan_devs = NULL;
|
|
i = tty_unregister_ldisc(N_SLCAN);
|
if (i)
|
printk(KERN_ERR "slcan: can't unregister ldisc (err %d)\n", i);
|
}
|
|
module_init(slcan_init);
|
module_exit(slcan_exit);
|
