#include <linux/delay.h>
#include <linux/init.h>
#include <linux/can.h>
+#include <linux/kthread.h>
/* Should be in include/linux/tty.h */
#define N_SLLIN 25
-
static __initdata const char banner[] =
KERN_INFO "sllin: serial line LIN interface driver\n";
module_param(maxdev, int, 0);
MODULE_PARM_DESC(maxdev, "Maximum number of sllin interfaces");
-/* maximum rx buffer len: extended CAN frame with timestamp */
-#define SLC_MTU (sizeof("T1111222281122334455667788EA5F\r")+1)
+/* maximum buffer len to store whole LIN message*/
+#define SLLIN_DATA_MAX 8
+#define SLLIN_BUFF_LEN (1 /*break*/ + 1 /*sync*/ + 1 /*ID*/ + \
+ SLLIN_DATA_MAX + 1 /*checksum*/)
+#define SLLIN_BUFF_BREAK 0
+#define SLLIN_BUFF_SYNC 1
+#define SLLIN_BUFF_ID 2
+#define SLLIN_BUFF_DATA 3
+
+enum slstate {
+ SLSTATE_IDLE = 0,
+ SLSTATE_BREAK_SENT,
+ SLSTATE_ID_SENT,
+ SLSTATE_RESPONSE_WAIT,
+ SLSTATE_RESPONSE_SENT,
+};
struct sllin {
int magic;
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 */
+ /* LIN message buffer and actual processed data counts */
+ unsigned char rx_buff[SLLIN_BUFF_LEN]; /* LIN Rx buffer */
+ unsigned char tx_buff[SLLIN_BUFF_LEN]; /* LIN Tx buffer */
+ int rx_expect; /* expected number of Rx chars */
+ int rx_lim; /* maximum Rx chars for ID */
+ int rx_cnt; /* message buffer Rx fill level */
+ int tx_lim; /* actual limit of bytes to Tx */
+ int tx_cnt; /* number of already Tx bytes */
+ char lin_master; /* node is a master node */
+ int lin_baud; /* LIN baudrate */
+ int lin_state; /* state */
+ int id_to_send; /* there is ID to be sent */
unsigned long flags; /* Flag values/ mode etc */
#define SLF_INUSE 0 /* Channel in use */
#define SLF_ERROR 1 /* Parity, etc. error */
+#define SLF_RXEVENT 2 /* Rx wake event */
+#define SLF_TXEVENT 3 /* Tx wake event */
+#define SLF_MSGEVENT 4 /* CAN message to sent */
- unsigned char leased;
dev_t line;
- pid_t pid;
+ struct task_struct *kwthread;
+ wait_queue_head_t kwt_wq;
};
static struct net_device **sllin_devs;
+const unsigned char sllin_id_parity_table[] = {
+ 0x80,0xc0,0x40,0x00,0xc0,0x80,0x00,0x40,
+ 0x00,0x40,0xc0,0x80,0x40,0x00,0x80,0xc0,
+ 0x40,0x00,0x80,0xc0,0x00,0x40,0xc0,0x80,
+ 0xc0,0x80,0x00,0x40,0x80,0xc0,0x40,0x00,
+ 0x00,0x40,0xc0,0x80,0x40,0x00,0x80,0xc0,
+ 0x80,0xc0,0x40,0x00,0xc0,0x80,0x00,0x40,
+ 0xc0,0x80,0x00,0x40,0x80,0xc0,0x40,0x00,
+ 0x40,0x00,0x80,0xc0,0x00,0x40,0xc0,0x80
+};
static int sltty_change_speed(struct tty_struct *tty, unsigned speed)
{
// sl->dev->stats.rx_bytes += cf.can_dlc;
}
-/* parse tty input stream */
-static void sllin_unesc(struct sllin *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)) {
- sll_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 SLLIN ENCAPSULATION *
char lframe[16] = {0x00, 0x55}; /* Fake break, Sync byte */
struct tty_struct *tty = sl->tty;
+ pr_debug("sllin: %s() invoked\n", __FUNCTION__);
+
/* We do care only about SFF frames */
if (cf->can_id & CAN_EFF_FLAG)
return;
/* Send only header */
if (cf->can_id & CAN_RTR_FLAG) {
+ pr_debug("sllin: %s() RTR CAN frame\n", __FUNCTION__);
lframe[2] = (u8)cf->can_id; /* Get one byte LIN ID */
- sltty_change_speed(tty, 1200);
+ sltty_change_speed(tty, sl->lin_baud / 2);
tty->ops->write(tty, &lframe[0], 1);
- sltty_change_speed(tty, 2400);
+ sltty_change_speed(tty, sl->lin_baud);
tty->ops->write(tty, &lframe[1], 1);
tty->ops->write(tty, &lframe[2], 1);
} else {
+ pr_debug("sllin: %s() non-RTR CAN frame\n", __FUNCTION__);
/* idx = strlen(sl->xbuff);
for (i = 0; i < cf->can_dlc; i++)
static void sllin_write_wakeup(struct tty_struct *tty)
{
int actual;
+ int remains;
struct sllin *sl = (struct sllin *) tty->disc_data;
/* First make sure we're connected. */
if (!sl || sl->magic != SLLIN_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;
+ if (sl->lin_state != SLSTATE_BREAK_SENT)
+ remains = sl->tx_lim - sl->tx_cnt;
+ else
+ remains = SLLIN_BUFF_BREAK + 1 - sl->tx_cnt;
+
+ if (remains > 0) {
+ actual = tty->ops->write(tty, sl->tx_buff + sl->tx_cnt, sl->tx_cnt - sl->tx_lim);
+ sl->tx_cnt += actual;
+
+ if (sl->tx_cnt < sl->tx_lim) {
+ printk(KERN_INFO "sllin_write_wakeup sent %d, remains %d, waiting\n",
+ sl->tx_cnt, sl->tx_lim - sl->tx_cnt);
+ return;
+ }
}
- actual = tty->ops->write(tty, sl->xhead, sl->xleft);
- sl->xleft -= actual;
- sl->xhead += actual;
+ clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
+ set_bit(SLF_TXEVENT, &sl->flags);
+ wake_up(&sl->kwt_wq);
+
+ printk(KERN_INFO "sllin_write_wakeup sent %d, wakeup\n", sl->tx_cnt);
}
/* Send a can_frame to a TTY queue. */
clear_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags);
}
netif_stop_queue(dev);
- sl->rcount = 0;
- sl->xleft = 0;
+ sl->rx_expect = 0;
+ sl->tx_lim = 0;
spin_unlock_bh(&sl->lock);
return 0;
{
struct sllin *sl = netdev_priv(dev);
+ pr_debug("sllin: %s() invoked\n", __FUNCTION__);
+
if (sl->tty == NULL)
return -ENODEV;
{
struct sllin *sl = (struct sllin *) tty->disc_data;
+ printk(KERN_INFO "sllin_receive_buf invoked\n");
+
if (!sl || sl->magic != SLLIN_MAGIC || !netif_running(sl->dev))
return;
cp++;
continue;
}
- sllin_unesc(sl, *cp++);
+
+ if (sl->rx_cnt < SLLIN_BUFF_LEN) {
+ sl->rx_buff[sl->rx_cnt++] = *cp++;
+ }
+ }
+
+ if(sl->rx_cnt >= sl->rx_expect) {
+ set_bit(SLF_RXEVENT, &sl->flags);
+ wake_up(&sl->kwt_wq);
+ printk(KERN_INFO "sllin_receive_buf count %d, wakeup\n", sl->rx_cnt);
+ } else {
+ printk(KERN_INFO "sllin_receive_buf count %d, waiting\n", sl->rx_cnt);
+ }
+}
+
+/*****************************************
+ * sllin message helper routines
+ *****************************************/
+
+int sllin_setup_msg(struct sllin *sl, int mode, int id,
+ unsigned char *data, int len)
+{
+ if (id > 0x3f)
+ return -1;
+
+ sl->rx_cnt = 0;
+ sl->tx_cnt = 0;
+ sl->rx_expect = 0;
+
+ sl->tx_buff[SLLIN_BUFF_BREAK] = 0;
+ sl->tx_buff[SLLIN_BUFF_SYNC] = 0x55;
+ sl->tx_buff[SLLIN_BUFF_ID] = id | sllin_id_parity_table[id];
+ sl->tx_lim = SLLIN_BUFF_DATA;
+
+ if ((data != NULL) && len) {
+ sl->tx_lim += len;
+ memcpy(sl->tx_buff + SLLIN_BUFF_DATA, data, len);
+ }
+ sl->rx_lim += len;
+
+ return 0;
+}
+
+
+int sllin_send_tx_buff(struct sllin *sl)
+{
+ struct tty_struct *tty = sl->tty;
+ int remains;
+ int res;
+
+ if (sl->lin_state != SLSTATE_BREAK_SENT)
+ remains = sl->tx_lim - sl->tx_cnt;
+ else
+ remains = 1;
+
+
+ res = tty->ops->write(tty, sl->tx_buff + sl->tx_cnt, remains);
+ if (res < 0)
+ return -1;
+
+ remains -= res;
+ sl->tx_cnt += res;
+
+ if (remains > 0) {
+ set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
+ res = tty->ops->write(tty, sl->tx_buff + sl->tx_cnt, remains);
+ if (res < 0) {
+ clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
+ return -1;
+ }
+
+ remains -= res;
+ sl->tx_cnt += res;
}
+
+ printk(KERN_INFO "sllin_send_tx_buff sent %d, remains %d\n",
+ sl->tx_cnt, remains);
+
+ return 0;
}
+int sllin_send_break(struct sllin *sl)
+{
+ struct tty_struct *tty = sl->tty;
+ unsigned long break_baud = sl->lin_baud;
+ int res;
+
+ //break_baud = (break_baud * 8) / 14;
+ break_baud /= 2;
+
+ sltty_change_speed(tty, break_baud);
+
+ sl->rx_expect = SLLIN_BUFF_BREAK + 1;
+
+ sl->lin_state = SLSTATE_BREAK_SENT;
+
+ res = sllin_send_tx_buff(sl);
+ if (res < 0) {
+ sl->lin_state = SLSTATE_IDLE;
+ return res;
+ }
+
+ return 0;
+}
+
+/*****************************************
+ * sllin_kwthread - kernel worker thread
+ *****************************************/
+
+int sllin_kwthread(void *ptr)
+{
+ struct sllin *sl = (struct sllin *)ptr;
+ struct tty_struct *tty = sl->tty;
+ int res;
+
+ printk(KERN_INFO "sllin: sllin_kwthread started.\n");
+
+ clear_bit(SLF_ERROR, &sl->flags);
+
+ sltty_change_speed(tty, sl->lin_baud);
+
+ sllin_setup_msg(sl, 0, 0x33, NULL, 0);
+ sl->id_to_send = 1;
+
+ while (!kthread_should_stop()) {
+
+ if ((sl->lin_state == SLSTATE_IDLE) && sl->lin_master &&
+ sl->id_to_send) {
+ if(sllin_send_break(sl)<0) {
+ /* error processing */
+ }
+
+ }
+
+ wait_event_killable(sl->kwt_wq, kthread_should_stop() ||
+ test_bit(SLF_RXEVENT, &sl->flags) ||
+ test_bit(SLF_TXEVENT, &sl->flags));
+
+ if (test_and_clear_bit(SLF_RXEVENT, &sl->flags)) {
+ printk(KERN_INFO "sllin_kthread RXEVENT \n");
+ }
+
+ if (test_and_clear_bit(SLF_TXEVENT, &sl->flags)) {
+ printk(KERN_INFO "sllin_kthread TXEVENT \n");
+ }
+
+ switch (sl->lin_state) {
+ case SLSTATE_BREAK_SENT:
+ if (sl->rx_cnt <= SLLIN_BUFF_BREAK)
+ continue;
+
+ res = sltty_change_speed(tty, sl->lin_baud);
+
+ sllin_send_tx_buff(sl);
+
+ sl->lin_state = SLSTATE_ID_SENT;
+
+ break;
+ case SLSTATE_ID_SENT:
+ sl->id_to_send = 0;
+ sl->lin_state = SLSTATE_IDLE;
+ break;
+ }
+
+
+
+ /* sll_bump(sl); send packet to the network layer */
+
+ /* sl->dev->stats.tx_packets++; send frames statistic */
+ /* netif_wake_queue(sl->dev); allow next Tx packet arrival */
+ }
+
+
+ printk(KERN_INFO "sllin: sllin_kwthread stopped.\n");
+
+ return 0;
+}
+
+
/************************************
* sllin_open helper routines.
************************************/
break;
sl = netdev_priv(dev);
- if (sl->tty || sl->leased)
+ if (sl->tty)
continue;
if (dev->flags & IFF_UP)
dev_close(dev);
{
struct sllin *sl;
int err;
+ pr_debug("sllin: %s() invoked\n", __FUNCTION__);
if (!capable(CAP_NET_ADMIN))
return -EPERM;
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 SLLIN initialization. */
- sl->rcount = 0;
- sl->xleft = 0;
+ sl->rx_cnt = 0;
+ sl->rx_expect = 0;
+ sl->tx_cnt = 0;
+ sl->tx_lim = 0;
+
+ sl->lin_baud = 2400;
+
+ sl->lin_master = 1;
+ sl->lin_state = SLSTATE_IDLE;
set_bit(SLF_INUSE, &sl->flags);
+ init_waitqueue_head(&sl->kwt_wq);
+ sl->kwthread = kthread_run(sllin_kwthread, sl, "sllin");
+ if (sl->kwthread == NULL)
+ goto err_free_chan;
+
err = register_netdevice(sl->dev);
if (err)
- goto err_free_chan;
+ goto err_free_chan_and_thread;
}
/* Done. We have linked the TTY line to a channel. */
rtnl_unlock();
- tty->receive_room = 65536; /* We don't flow control */
+ tty->receive_room = SLLIN_BUFF_LEN * 40; /* We don't flow control */
/* TTY layer expects 0 on success */
return 0;
+err_free_chan_and_thread:
+ kthread_stop(sl->kwthread);
+ sl->kwthread = NULL;
+
err_free_chan:
sl->tty = NULL;
tty->disc_data = NULL;
if (!sl || sl->magic != SLLIN_MAGIC || sl->tty != tty)
return;
+ kthread_stop(sl->kwthread);
+ sl->kwthread = NULL;
+
tty->disc_data = NULL;
sl->tty = NULL;
- if (!sl->leased)
- sl->line = 0;
/* Flush network side */
unregister_netdev(sl->dev);
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