From: Dario Binacchi Date: Tue, 28 Jun 2022 16:31:33 +0000 (+0200) Subject: can: slcan: move driver into separate sub directory X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=98b12064591d635db86da4957b547067dc6897cc;p=linux.git can: slcan: move driver into separate sub directory This patch moves the slcan driver into a separate directory, a later patch will add more files. Link: https://lore.kernel.org/all/20220628163137.413025-10-dario.binacchi@amarulasolutions.com Signed-off-by: Dario Binacchi Signed-off-by: Marc Kleine-Budde --- diff --git a/drivers/net/can/Makefile b/drivers/net/can/Makefile index cafa0e0a3dfe1..61c75ce9d500d 100644 --- a/drivers/net/can/Makefile +++ b/drivers/net/can/Makefile @@ -5,7 +5,7 @@ obj-$(CONFIG_CAN_VCAN) += vcan.o obj-$(CONFIG_CAN_VXCAN) += vxcan.o -obj-$(CONFIG_CAN_SLCAN) += slcan.o +obj-$(CONFIG_CAN_SLCAN) += slcan/ obj-y += dev/ obj-y += rcar/ diff --git a/drivers/net/can/slcan.c b/drivers/net/can/slcan.c deleted file mode 100644 index 249b5ade06fce..0000000000000 --- a/drivers/net/can/slcan.c +++ /dev/null @@ -1,885 +0,0 @@ -/* - * 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 - * Fred N. van Kempen - * slcan.c Author : Oliver Hartkopp - * - * This program is free software; you can redistribute it and/or modify it - * 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. - * - * 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. - * - * 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 - * - * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS - * "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 - * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT - * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE - * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH - * DAMAGE. - * - */ - -#include -#include - -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include - -MODULE_ALIAS_LDISC(N_SLCAN); -MODULE_DESCRIPTION("serial line CAN interface"); -MODULE_LICENSE("GPL"); -MODULE_AUTHOR("Oliver Hartkopp "); - -#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); -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 -#define SLC_SFF_ID_LEN 3 -#define SLC_EFF_ID_LEN 8 - -struct slcan { - struct can_priv can; - int magic; - - /* Various fields. */ - struct tty_struct *tty; /* ptr to TTY structure */ - struct net_device *dev; /* easy for intr handling */ - spinlock_t lock; - struct work_struct tx_work; /* Flushes transmit buffer */ - - /* These are pointers to the malloc()ed frame buffers. */ - unsigned char rbuff[SLC_MTU]; /* receiver buffer */ - int rcount; /* received chars counter */ - unsigned char xbuff[SLC_MTU]; /* transmitter buffer */ - unsigned char *xhead; /* pointer to next XMIT byte */ - int xleft; /* bytes left in XMIT queue */ - - unsigned long flags; /* Flag values/ mode etc */ -#define SLF_INUSE 0 /* Channel in use */ -#define SLF_ERROR 1 /* Parity, etc. error */ -#define SLF_XCMD 2 /* Command transmission */ - wait_queue_head_t xcmd_wait; /* Wait queue for commands */ - /* transmission */ -}; - -static struct net_device **slcan_devs; - -static const u32 slcan_bitrate_const[] = { - 10000, 20000, 50000, 100000, 125000, - 250000, 500000, 800000, 1000000 -}; - - /************************************************************************ - * 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 (len) which can be from 0 to 8 - * and up to 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. - * - * The SLCAN ASCII representation of these different frame types is: - * * - * - * 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 is 3 (standard) or 8 (extended) bytes in ASCII Hex (base64). - * The is a one byte ASCII number ('0' - '8') - * The section has at much ASCII Hex bytes as defined by the - * - * Examples: - * - * t1230 : can_id 0x123, len 0, no data - * t4563112233 : can_id 0x456, len 3, data 0x11 0x22 0x33 - * T12ABCDEF2AA55 : extended can_id 0x12ABCDEF, len 2, data 0xAA 0x55 - * r1230 : can_id 0x123, len 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; - - skb = alloc_can_skb(sl->dev, &cf); - if (unlikely(!skb)) { - sl->dev->stats.rx_dropped++; - return; - } - - switch (*cmd) { - case 'r': - cf->can_id = CAN_RTR_FLAG; - fallthrough; - case 't': - /* store dlc ASCII value and terminate SFF CAN ID string */ - cf->len = 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->len = sl->rbuff[SLC_CMD_LEN + SLC_EFF_ID_LEN]; - 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: - goto decode_failed; - } - - if (kstrtou32(sl->rbuff + SLC_CMD_LEN, 16, &tmpid)) - goto decode_failed; - - cf->can_id |= tmpid; - - /* get len from sanitized ASCII value */ - if (cf->len >= '0' && cf->len < '9') - cf->len -= '0'; - else - goto decode_failed; - - /* 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->len; i++) { - tmp = hex_to_bin(*cmd++); - if (tmp < 0) - goto decode_failed; - - cf->data[i] = (tmp << 4); - tmp = hex_to_bin(*cmd++); - if (tmp < 0) - goto decode_failed; - - cf->data[i] |= tmp; - } - } - - sl->dev->stats.rx_packets++; - if (!(cf->can_id & CAN_RTR_FLAG)) - sl->dev->stats.rx_bytes += cf->len; - - netif_rx(skb); - return; - -decode_failed: - sl->dev->stats.rx_errors++; - dev_kfree_skb(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->len + '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->len; i++) - pos = hex_byte_pack_upper(pos, cf->data[i]); - - sl->dev->stats.tx_bytes += cf->len; - } - - *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; -} - -/* 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 || - (unlikely(!netif_running(sl->dev)) && - likely(!test_bit(SLF_XCMD, &sl->flags)))) { - spin_unlock_bh(&sl->lock); - return; - } - - if (sl->xleft <= 0) { - if (unlikely(test_bit(SLF_XCMD, &sl->flags))) { - clear_bit(SLF_XCMD, &sl->flags); - clear_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags); - spin_unlock_bh(&sl->lock); - wake_up(&sl->xcmd_wait); - return; - } - - /* 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) - schedule_work(&sl->tx_work); - 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 (can_dropped_invalid_skb(dev, skb)) - return NETDEV_TX_OK; - - spin_lock(&sl->lock); - if (!netif_running(dev)) { - spin_unlock(&sl->lock); - netdev_warn(dev, "xmit: iface is down\n"); - 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. - ******************************************/ - -static int slcan_transmit_cmd(struct slcan *sl, const unsigned char *cmd) -{ - int ret, actual, n; - - spin_lock(&sl->lock); - if (!sl->tty) { - spin_unlock(&sl->lock); - return -ENODEV; - } - - n = snprintf(sl->xbuff, sizeof(sl->xbuff), "%s", cmd); - set_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags); - actual = sl->tty->ops->write(sl->tty, sl->xbuff, n); - sl->xleft = n - actual; - sl->xhead = sl->xbuff + actual; - set_bit(SLF_XCMD, &sl->flags); - spin_unlock(&sl->lock); - ret = wait_event_interruptible_timeout(sl->xcmd_wait, - !test_bit(SLF_XCMD, &sl->flags), - HZ); - clear_bit(SLF_XCMD, &sl->flags); - if (ret == -ERESTARTSYS) - return ret; - - if (ret == 0) - return -ETIMEDOUT; - - return 0; -} - -/* Netdevice UP -> DOWN routine */ -static int slc_close(struct net_device *dev) -{ - struct slcan *sl = netdev_priv(dev); - int err; - - spin_lock_bh(&sl->lock); - if (sl->tty) { - if (sl->can.bittiming.bitrate && - sl->can.bittiming.bitrate != CAN_BITRATE_UNKNOWN) { - spin_unlock_bh(&sl->lock); - err = slcan_transmit_cmd(sl, "C\r"); - spin_lock_bh(&sl->lock); - if (err) - netdev_warn(dev, - "failed to send close command 'C\\r'\n"); - } - - /* TTY discipline is running. */ - clear_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags); - } - netif_stop_queue(dev); - close_candev(dev); - sl->can.state = CAN_STATE_STOPPED; - if (sl->can.bittiming.bitrate == CAN_BITRATE_UNKNOWN) - sl->can.bittiming.bitrate = CAN_BITRATE_UNSET; - - 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); - unsigned char cmd[SLC_MTU]; - int err, s; - - if (sl->tty == NULL) - return -ENODEV; - - /* The baud rate is not set with the command - * `ip link set type can bitrate ' and therefore - * can.bittiming.bitrate is CAN_BITRATE_UNSET (0), causing - * open_candev() to fail. So let's set to a fake value. - */ - if (sl->can.bittiming.bitrate == CAN_BITRATE_UNSET) - sl->can.bittiming.bitrate = CAN_BITRATE_UNKNOWN; - - err = open_candev(dev); - if (err) { - netdev_err(dev, "failed to open can device\n"); - return err; - } - - sl->flags &= BIT(SLF_INUSE); - - if (sl->can.bittiming.bitrate != CAN_BITRATE_UNKNOWN) { - for (s = 0; s < ARRAY_SIZE(slcan_bitrate_const); s++) { - if (sl->can.bittiming.bitrate == slcan_bitrate_const[s]) - break; - } - - /* The CAN framework has already validate the bitrate value, - * so we can avoid to check if `s' has been properly set. - */ - - snprintf(cmd, sizeof(cmd), "C\rS%d\r", s); - err = slcan_transmit_cmd(sl, cmd); - if (err) { - netdev_err(dev, - "failed to send bitrate command 'C\\rS%d\\r'\n", - s); - goto cmd_transmit_failed; - } - - err = slcan_transmit_cmd(sl, "O\r"); - if (err) { - netdev_err(dev, "failed to send open command 'O\\r'\n"); - goto cmd_transmit_failed; - } - } - - sl->can.state = CAN_STATE_ERROR_ACTIVE; - netif_start_queue(dev); - return 0; - -cmd_transmit_failed: - close_candev(dev); - return err; -} - -static void slc_dealloc(struct slcan *sl) -{ - int i = sl->dev->base_addr; - - free_candev(sl->dev); - 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, -}; - -/****************************************** - 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, const 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; - 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; - - dev = alloc_candev(sizeof(*sl), 1); - if (!dev) - return NULL; - - snprintf(dev->name, sizeof(dev->name), "slcan%d", i); - dev->netdev_ops = &slc_netdev_ops; - dev->base_addr = i; - sl = netdev_priv(dev); - - /* Initialize channel control data */ - sl->magic = SLCAN_MAGIC; - sl->dev = dev; - sl->can.bitrate_const = slcan_bitrate_const; - sl->can.bitrate_const_cnt = ARRAY_SIZE(slcan_bitrate_const); - spin_lock_init(&sl->lock); - INIT_WORK(&sl->tx_work, slcan_transmit); - init_waitqueue_head(&sl->xcmd_wait); - 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); - - rtnl_unlock(); - err = register_candev(sl->dev); - if (err) { - pr_err("slcan: can't register candev\n"); - goto err_free_chan; - } - } else { - rtnl_unlock(); - } - - tty->receive_room = 65536; /* We don't flow control */ - - /* TTY layer expects 0 on success */ - return 0; - -err_free_chan: - rtnl_lock(); - sl->tty = NULL; - tty->disc_data = NULL; - clear_bit(SLF_INUSE, &sl->flags); - slc_dealloc(sl); - rtnl_unlock(); - 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); - - slc_close(sl->dev); - unregister_candev(sl->dev); - rtnl_lock(); - slc_dealloc(sl); - rtnl_unlock(); -} - -static void slcan_hangup(struct tty_struct *tty) -{ - slcan_close(tty); -} - -/* Perform I/O control on an active SLCAN channel. */ -static int slcan_ioctl(struct tty_struct *tty, 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, cmd, arg); - } -} - -static struct tty_ldisc_ops slc_ldisc = { - .owner = THIS_MODULE, - .num = N_SLCAN, - .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(&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; - - sl = netdev_priv(dev); - if (sl->tty) { - netdev_err(dev, "tty discipline still running\n"); - } - - slc_close(dev); - unregister_candev(dev); - slc_dealloc(sl); - } - - kfree(slcan_devs); - slcan_devs = NULL; - - tty_unregister_ldisc(&slc_ldisc); -} - -module_init(slcan_init); -module_exit(slcan_exit); diff --git a/drivers/net/can/slcan/Makefile b/drivers/net/can/slcan/Makefile new file mode 100644 index 0000000000000..2e84f7bf7617d --- /dev/null +++ b/drivers/net/can/slcan/Makefile @@ -0,0 +1,6 @@ +# SPDX-License-Identifier: GPL-2.0 + +obj-$(CONFIG_CAN_SLCAN) += slcan.o + +slcan-objs := +slcan-objs += slcan-core.o diff --git a/drivers/net/can/slcan/slcan-core.c b/drivers/net/can/slcan/slcan-core.c new file mode 100644 index 0000000000000..249b5ade06fce --- /dev/null +++ b/drivers/net/can/slcan/slcan-core.c @@ -0,0 +1,885 @@ +/* + * 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 + * Fred N. van Kempen + * slcan.c Author : Oliver Hartkopp + * + * This program is free software; you can redistribute it and/or modify it + * 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. + * + * 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. + * + * 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 + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS + * "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 + * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE + * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH + * DAMAGE. + * + */ + +#include +#include + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +MODULE_ALIAS_LDISC(N_SLCAN); +MODULE_DESCRIPTION("serial line CAN interface"); +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Oliver Hartkopp "); + +#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); +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 +#define SLC_SFF_ID_LEN 3 +#define SLC_EFF_ID_LEN 8 + +struct slcan { + struct can_priv can; + int magic; + + /* Various fields. */ + struct tty_struct *tty; /* ptr to TTY structure */ + struct net_device *dev; /* easy for intr handling */ + spinlock_t lock; + struct work_struct tx_work; /* Flushes transmit buffer */ + + /* These are pointers to the malloc()ed frame buffers. */ + unsigned char rbuff[SLC_MTU]; /* receiver buffer */ + int rcount; /* received chars counter */ + unsigned char xbuff[SLC_MTU]; /* transmitter buffer */ + unsigned char *xhead; /* pointer to next XMIT byte */ + int xleft; /* bytes left in XMIT queue */ + + unsigned long flags; /* Flag values/ mode etc */ +#define SLF_INUSE 0 /* Channel in use */ +#define SLF_ERROR 1 /* Parity, etc. error */ +#define SLF_XCMD 2 /* Command transmission */ + wait_queue_head_t xcmd_wait; /* Wait queue for commands */ + /* transmission */ +}; + +static struct net_device **slcan_devs; + +static const u32 slcan_bitrate_const[] = { + 10000, 20000, 50000, 100000, 125000, + 250000, 500000, 800000, 1000000 +}; + + /************************************************************************ + * 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 (len) which can be from 0 to 8 + * and up to 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. + * + * The SLCAN ASCII representation of these different frame types is: + * * + * + * 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 is 3 (standard) or 8 (extended) bytes in ASCII Hex (base64). + * The is a one byte ASCII number ('0' - '8') + * The section has at much ASCII Hex bytes as defined by the + * + * Examples: + * + * t1230 : can_id 0x123, len 0, no data + * t4563112233 : can_id 0x456, len 3, data 0x11 0x22 0x33 + * T12ABCDEF2AA55 : extended can_id 0x12ABCDEF, len 2, data 0xAA 0x55 + * r1230 : can_id 0x123, len 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; + + skb = alloc_can_skb(sl->dev, &cf); + if (unlikely(!skb)) { + sl->dev->stats.rx_dropped++; + return; + } + + switch (*cmd) { + case 'r': + cf->can_id = CAN_RTR_FLAG; + fallthrough; + case 't': + /* store dlc ASCII value and terminate SFF CAN ID string */ + cf->len = 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->len = sl->rbuff[SLC_CMD_LEN + SLC_EFF_ID_LEN]; + 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: + goto decode_failed; + } + + if (kstrtou32(sl->rbuff + SLC_CMD_LEN, 16, &tmpid)) + goto decode_failed; + + cf->can_id |= tmpid; + + /* get len from sanitized ASCII value */ + if (cf->len >= '0' && cf->len < '9') + cf->len -= '0'; + else + goto decode_failed; + + /* 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->len; i++) { + tmp = hex_to_bin(*cmd++); + if (tmp < 0) + goto decode_failed; + + cf->data[i] = (tmp << 4); + tmp = hex_to_bin(*cmd++); + if (tmp < 0) + goto decode_failed; + + cf->data[i] |= tmp; + } + } + + sl->dev->stats.rx_packets++; + if (!(cf->can_id & CAN_RTR_FLAG)) + sl->dev->stats.rx_bytes += cf->len; + + netif_rx(skb); + return; + +decode_failed: + sl->dev->stats.rx_errors++; + dev_kfree_skb(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->len + '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->len; i++) + pos = hex_byte_pack_upper(pos, cf->data[i]); + + sl->dev->stats.tx_bytes += cf->len; + } + + *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; +} + +/* 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 || + (unlikely(!netif_running(sl->dev)) && + likely(!test_bit(SLF_XCMD, &sl->flags)))) { + spin_unlock_bh(&sl->lock); + return; + } + + if (sl->xleft <= 0) { + if (unlikely(test_bit(SLF_XCMD, &sl->flags))) { + clear_bit(SLF_XCMD, &sl->flags); + clear_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags); + spin_unlock_bh(&sl->lock); + wake_up(&sl->xcmd_wait); + return; + } + + /* 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) + schedule_work(&sl->tx_work); + 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 (can_dropped_invalid_skb(dev, skb)) + return NETDEV_TX_OK; + + spin_lock(&sl->lock); + if (!netif_running(dev)) { + spin_unlock(&sl->lock); + netdev_warn(dev, "xmit: iface is down\n"); + 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. + ******************************************/ + +static int slcan_transmit_cmd(struct slcan *sl, const unsigned char *cmd) +{ + int ret, actual, n; + + spin_lock(&sl->lock); + if (!sl->tty) { + spin_unlock(&sl->lock); + return -ENODEV; + } + + n = snprintf(sl->xbuff, sizeof(sl->xbuff), "%s", cmd); + set_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags); + actual = sl->tty->ops->write(sl->tty, sl->xbuff, n); + sl->xleft = n - actual; + sl->xhead = sl->xbuff + actual; + set_bit(SLF_XCMD, &sl->flags); + spin_unlock(&sl->lock); + ret = wait_event_interruptible_timeout(sl->xcmd_wait, + !test_bit(SLF_XCMD, &sl->flags), + HZ); + clear_bit(SLF_XCMD, &sl->flags); + if (ret == -ERESTARTSYS) + return ret; + + if (ret == 0) + return -ETIMEDOUT; + + return 0; +} + +/* Netdevice UP -> DOWN routine */ +static int slc_close(struct net_device *dev) +{ + struct slcan *sl = netdev_priv(dev); + int err; + + spin_lock_bh(&sl->lock); + if (sl->tty) { + if (sl->can.bittiming.bitrate && + sl->can.bittiming.bitrate != CAN_BITRATE_UNKNOWN) { + spin_unlock_bh(&sl->lock); + err = slcan_transmit_cmd(sl, "C\r"); + spin_lock_bh(&sl->lock); + if (err) + netdev_warn(dev, + "failed to send close command 'C\\r'\n"); + } + + /* TTY discipline is running. */ + clear_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags); + } + netif_stop_queue(dev); + close_candev(dev); + sl->can.state = CAN_STATE_STOPPED; + if (sl->can.bittiming.bitrate == CAN_BITRATE_UNKNOWN) + sl->can.bittiming.bitrate = CAN_BITRATE_UNSET; + + 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); + unsigned char cmd[SLC_MTU]; + int err, s; + + if (sl->tty == NULL) + return -ENODEV; + + /* The baud rate is not set with the command + * `ip link set type can bitrate ' and therefore + * can.bittiming.bitrate is CAN_BITRATE_UNSET (0), causing + * open_candev() to fail. So let's set to a fake value. + */ + if (sl->can.bittiming.bitrate == CAN_BITRATE_UNSET) + sl->can.bittiming.bitrate = CAN_BITRATE_UNKNOWN; + + err = open_candev(dev); + if (err) { + netdev_err(dev, "failed to open can device\n"); + return err; + } + + sl->flags &= BIT(SLF_INUSE); + + if (sl->can.bittiming.bitrate != CAN_BITRATE_UNKNOWN) { + for (s = 0; s < ARRAY_SIZE(slcan_bitrate_const); s++) { + if (sl->can.bittiming.bitrate == slcan_bitrate_const[s]) + break; + } + + /* The CAN framework has already validate the bitrate value, + * so we can avoid to check if `s' has been properly set. + */ + + snprintf(cmd, sizeof(cmd), "C\rS%d\r", s); + err = slcan_transmit_cmd(sl, cmd); + if (err) { + netdev_err(dev, + "failed to send bitrate command 'C\\rS%d\\r'\n", + s); + goto cmd_transmit_failed; + } + + err = slcan_transmit_cmd(sl, "O\r"); + if (err) { + netdev_err(dev, "failed to send open command 'O\\r'\n"); + goto cmd_transmit_failed; + } + } + + sl->can.state = CAN_STATE_ERROR_ACTIVE; + netif_start_queue(dev); + return 0; + +cmd_transmit_failed: + close_candev(dev); + return err; +} + +static void slc_dealloc(struct slcan *sl) +{ + int i = sl->dev->base_addr; + + free_candev(sl->dev); + 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, +}; + +/****************************************** + 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, const 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; + 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; + + dev = alloc_candev(sizeof(*sl), 1); + if (!dev) + return NULL; + + snprintf(dev->name, sizeof(dev->name), "slcan%d", i); + dev->netdev_ops = &slc_netdev_ops; + dev->base_addr = i; + sl = netdev_priv(dev); + + /* Initialize channel control data */ + sl->magic = SLCAN_MAGIC; + sl->dev = dev; + sl->can.bitrate_const = slcan_bitrate_const; + sl->can.bitrate_const_cnt = ARRAY_SIZE(slcan_bitrate_const); + spin_lock_init(&sl->lock); + INIT_WORK(&sl->tx_work, slcan_transmit); + init_waitqueue_head(&sl->xcmd_wait); + 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); + + rtnl_unlock(); + err = register_candev(sl->dev); + if (err) { + pr_err("slcan: can't register candev\n"); + goto err_free_chan; + } + } else { + rtnl_unlock(); + } + + tty->receive_room = 65536; /* We don't flow control */ + + /* TTY layer expects 0 on success */ + return 0; + +err_free_chan: + rtnl_lock(); + sl->tty = NULL; + tty->disc_data = NULL; + clear_bit(SLF_INUSE, &sl->flags); + slc_dealloc(sl); + rtnl_unlock(); + 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); + + slc_close(sl->dev); + unregister_candev(sl->dev); + rtnl_lock(); + slc_dealloc(sl); + rtnl_unlock(); +} + +static void slcan_hangup(struct tty_struct *tty) +{ + slcan_close(tty); +} + +/* Perform I/O control on an active SLCAN channel. */ +static int slcan_ioctl(struct tty_struct *tty, 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, cmd, arg); + } +} + +static struct tty_ldisc_ops slc_ldisc = { + .owner = THIS_MODULE, + .num = N_SLCAN, + .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(&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; + + sl = netdev_priv(dev); + if (sl->tty) { + netdev_err(dev, "tty discipline still running\n"); + } + + slc_close(dev); + unregister_candev(dev); + slc_dealloc(sl); + } + + kfree(slcan_devs); + slcan_devs = NULL; + + tty_unregister_ldisc(&slc_ldisc); +} + +module_init(slcan_init); +module_exit(slcan_exit);