From 7f0102aa259dec7f56c0a36ac52a90eec60f7400 Mon Sep 17 00:00:00 2001 From: Pavel Pisa Date: Tue, 22 Nov 2011 22:17:01 +0100 Subject: [PATCH] Basic functions to synchronize Tx with LIN state automata implemented. Signed-off-by: Pavel Pisa --- sllin/sllin.c | 263 ++++++++++++++++++++++++++++++++++++++++---------- 1 file changed, 213 insertions(+), 50 deletions(-) diff --git a/sllin/sllin.c b/sllin/sllin.c index 7793541..cf387e7 100644 --- a/sllin/sllin.c +++ b/sllin/sllin.c @@ -78,8 +78,22 @@ static int maxdev = 10; /* MAX number of SLLIN channels; 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; @@ -89,16 +103,25 @@ struct sllin { 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_sent; /* 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; @@ -108,6 +131,16 @@ struct sllin { 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) { @@ -193,28 +226,6 @@ static void sll_bump(struct sllin *sl) // 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 * @@ -238,9 +249,9 @@ static void sll_encaps(struct sllin *sl, struct can_frame *cf) 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 { @@ -275,24 +286,30 @@ static void sll_encaps(struct sllin *sl, struct can_frame *cf) 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) + 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); + } /* Send a can_frame to a TTY queue. */ @@ -339,8 +356,8 @@ static int sll_close(struct net_device *dev) 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; @@ -421,10 +438,102 @@ static void sllin_receive_buf(struct tty_struct *tty, 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); } } +/***************************************** + * 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; + } + } + sl->tx_cnt += res; + + 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; + + 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 *****************************************/ @@ -432,15 +541,62 @@ static void sllin_receive_buf(struct tty_struct *tty, 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); + while (!kthread_should_stop()) { - - wait_event_killable(sl->kwt_wq, kthread_should_stop()); + if ((sl->lin_state == SLSTATE_IDLE) && sl->lin_master && + sl->id_to_sent) { + 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)) { + + } + + if (test_and_clear_bit(SLF_TXEVENT, &sl->flags)) { + + } + + 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; + } + + + + /* 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; @@ -572,8 +728,15 @@ static int sllin_open(struct tty_struct *tty) 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); @@ -589,7 +752,7 @@ static int sllin_open(struct tty_struct *tty) /* 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; -- 2.39.2