diff options
Diffstat (limited to 'drivers/net/can/slcan.c')
| -rw-r--r-- | drivers/net/can/slcan.c | 755 |
1 files changed, 755 insertions, 0 deletions
diff --git a/drivers/net/can/slcan.c b/drivers/net/can/slcan.c new file mode 100644 index 00000000000..420e95ecc19 --- /dev/null +++ b/drivers/net/can/slcan.c @@ -0,0 +1,755 @@ +/* + * slcan.c - serial line CAN interface driver (using tty line discipline) + * + * This file is derived from linux/drivers/net/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> + * + * 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, write to the Free Software Foundation, Inc., + * 59 Temple Place, Suite 330, Boston, MA 02111-1307. You can also get it + * at 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. + * + * Send feedback to <socketcan-users@lists.berlios.de> + * + */ + +#include <linux/module.h> +#include <linux/moduleparam.h> + +#include <asm/system.h> +#include <linux/uaccess.h> +#include <linux/bitops.h> +#include <linux/string.h> +#include <linux/tty.h> +#include <linux/errno.h> +#include <linux/netdevice.h> +#include <linux/skbuff.h> +#include <linux/rtnetlink.h> +#include <linux/if_arp.h> +#include <linux/if_ether.h> +#include <linux/delay.h> +#include <linux/init.h> +#include <linux/can.h> + +static __initdata const char banner[] = + KERN_INFO "slcan: serial line CAN interface driver\n"; + +MODULE_ALIAS_LDISC(N_SLCAN); +MODULE_DESCRIPTION("serial line CAN interface"); +MODULE_LICENSE("GPL"); +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); +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) + +struct slcan { + int magic; + + /* Various fields. */ + struct tty_struct *tty; /* ptr to TTY structure */ + struct net_device *dev; /* easy for intr handling */ + spinlock_t lock; + + /* 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 */ + + unsigned char leased; + dev_t line; + pid_t pid; +}; + +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. + * + * The SLCAN ASCII representation of these different frame types is: + * <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 * + ************************************************************************/ + +static int asc2nibble(char c) +{ + + if ((c >= '0') && (c <= '9')) + return c - '0'; + + if ((c >= 'A') && (c <= 'F')) + return c - 'A' + 10; + + if ((c >= 'a') && (c <= 'f')) + return c - 'a' + 10; + + return 16; /* error */ +} + +/* 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, dlc_pos, tmp; + unsigned long ultmp; + char cmd = sl->rbuff[0]; + + if ((cmd != 't') && (cmd != 'T') && (cmd != 'r') && (cmd != 'R')) + return; + + if (cmd & 0x20) /* tiny chars 'r' 't' => standard frame format */ + dlc_pos = 4; /* dlc position tiiid */ + else + dlc_pos = 9; /* dlc position Tiiiiiiiid */ + + if (!((sl->rbuff[dlc_pos] >= '0') && (sl->rbuff[dlc_pos] < '9'))) + return; + + cf.can_dlc = sl->rbuff[dlc_pos] - '0'; /* get can_dlc from ASCII val */ + + sl->rbuff[dlc_pos] = 0; /* terminate can_id string */ + + if (strict_strtoul(sl->rbuff+1, 16, &ultmp)) + return; + + cf.can_id = ultmp; + + if (!(cmd & 0x20)) /* NO tiny chars => extended frame format */ + cf.can_id |= CAN_EFF_FLAG; + + if ((cmd | 0x20) == 'r') /* RTR frame */ + cf.can_id |= CAN_RTR_FLAG; + + *(u64 *) (&cf.data) = 0; /* clear payload */ + + for (i = 0, dlc_pos++; i < cf.can_dlc; i++) { + + tmp = asc2nibble(sl->rbuff[dlc_pos++]); + if (tmp > 0x0F) + return; + cf.data[i] = (tmp << 4); + tmp = asc2nibble(sl->rbuff[dlc_pos++]); + if (tmp > 0x0F) + return; + cf.data[i] |= tmp; + } + + + skb = dev_alloc_skb(sizeof(struct can_frame)); + if (!skb) + return; + + skb->dev = sl->dev; + skb->protocol = htons(ETH_P_CAN); + skb->pkt_type = PACKET_BROADCAST; + skb->ip_summed = CHECKSUM_UNNECESSARY; + memcpy(skb_put(skb, sizeof(struct can_frame)), + &cf, sizeof(struct can_frame)); + netif_rx(skb); + + sl->dev->stats.rx_packets++; + sl->dev->stats.rx_bytes += cf.can_dlc; +} + +/* 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, idx, i; + char cmd; + + if (cf->can_id & CAN_RTR_FLAG) + cmd = 'R'; /* becomes 'r' in standard frame format */ + else + cmd = 'T'; /* becomes 't' in standard frame format */ + + if (cf->can_id & CAN_EFF_FLAG) + sprintf(sl->xbuff, "%c%08X%d", cmd, + cf->can_id & CAN_EFF_MASK, cf->can_dlc); + else + sprintf(sl->xbuff, "%c%03X%d", cmd | 0x20, + cf->can_id & CAN_SFF_MASK, cf->can_dlc); + + idx = strlen(sl->xbuff); + + for (i = 0; i < cf->can_dlc; i++) + sprintf(&sl->xbuff[idx + 2*i], "%02X", cf->data[i]); + + strcat(sl->xbuff, "\r"); /* add terminating character */ + + /* 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, strlen(sl->xbuff)); + sl->xleft = strlen(sl->xbuff) - actual; + sl->xhead = sl->xbuff + actual; + sl->dev->stats.tx_bytes += cf->can_dlc; +} + +/* + * Called by the driver when there's room for more data. If we have + * more packets to send, we send them here. + */ +static void slcan_write_wakeup(struct tty_struct *tty) +{ + int actual; + struct slcan *sl = (struct slcan *) tty->disc_data; + + /* First make sure we're connected. */ + if (!sl || sl->magic != SLCAN_MAGIC || !netif_running(sl->dev)) + 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, &tty->flags); + netif_wake_queue(sl->dev); + return; + } + + actual = tty->ops->write(tty, sl->xhead, sl->xleft); + sl->xleft -= actual; + sl->xhead += actual; +} + +/* 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 != sizeof(struct can_frame)) + 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; + free_netdev(dev); + slcan_devs[i] = NULL; +} + +static const struct net_device_ops slc_netdev_ops = { + .ndo_open = slc_open, + .ndo_stop = slc_close, + .ndo_start_xmit = slc_xmit, +}; + +static void slc_setup(struct net_device *dev) +{ + dev->netdev_ops = &slc_netdev_ops; + dev->destructor = slc_free_netdev; + + dev->hard_header_len = 0; + dev->addr_len = 0; + dev->tx_queue_len = 10; + + dev->mtu = sizeof(struct can_frame); + dev->type = ARPHRD_CAN; + + /* New-style flags. */ + dev->flags = IFF_NOARP; + dev->features = NETIF_F_NO_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 || sl->leased) + 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(dev_t line) +{ + int i; + struct net_device *dev = NULL; + struct slcan *sl; + + if (slcan_devs == NULL) + return NULL; /* Master array missing ! */ + + 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; + + if (dev) { + sl = netdev_priv(dev); + if (test_bit(SLF_INUSE, &sl->flags)) { + unregister_netdevice(dev); + dev = NULL; + slcan_devs[i] = NULL; + } + } + + if (!dev) { + char name[IFNAMSIZ]; + sprintf(name, "slcan%d", i); + + dev = alloc_netdev(sizeof(*sl), name, 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); + 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(tty_devnum(tty)); + if (sl == NULL) + goto err_exit; + + sl->tty = tty; + tty->disc_data = sl; + sl->line = tty_devnum(tty); + sl->pid = current->pid; + + 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 */ + return sl->dev->base_addr; + +err_free_chan: + sl->tty = NULL; + tty->disc_data = NULL; + clear_bit(SLF_INUSE, &sl->flags); + +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; + + tty->disc_data = NULL; + sl->tty = NULL; + if (!sl->leased) + sl->line = 0; + + /* 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 */ + + printk(banner); + printk(KERN_INFO "slcan: %d dynamic interface channels.\n", maxdev); + + slcan_devs = kzalloc(sizeof(struct net_device *)*maxdev, GFP_KERNEL); + if (!slcan_devs) { + printk(KERN_ERR "slcan: can't allocate slcan device array!\n"); + 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); + /* Intentionally leak the control block. */ + dev->destructor = NULL; + } + + 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); |