uart.c

linux-2.4.29操作系统的源码

	 */
	if ((cflag & CREAD) == 0)
		info->read_status_mask &= ~BD_SC_EMPTY;
	save_flags(flags); cli();

	/* Start bit has not been added (so don't, because we would just
	 * subtract it later), and we need to add one for the number of
	 * stops bits (there is always at least one).
	 */
	bits++;
	idx = PORT_NUM(state->smc_scc_num);
	if (PORT_IS_SCC(state->smc_scc_num)) {
		sccp = &cpmp->cp_scc[idx];
		new_mode = (sbits << 12) | scval;
		prev_mode = sccp->scc_pmsr;
		if (!(prev_mode & SCU_PMSR_PEN))
			/* If parity is disabled, mask out even/odd */
			prev_mode &= ~(SCU_PMSR_TPM|SCU_PMSR_RPM);
		if (prev_mode != new_mode)
			sccp->scc_pmsr = new_mode;
	}
	else {
		smcp = &cpmp->cp_smc[idx];

		/* Set the mode register.  We want to keep a copy of the
		 * enables, because we want to put them back if they were
		 * present.
		 */
		prev_mode = smcp->smc_smcmr & (SMCMR_REN | SMCMR_TEN);
		new_mode = smcr_mk_clen(bits) | cval | SMCMR_SM_UART
			| prev_mode;
		if (!(prev_mode & SMCMR_PEN))
			/* If parity is disabled, mask out even/odd */
			prev_mode &= ~SMCMR_PM_EVEN;
		if (prev_mode != new_mode)
			smcp->smc_smcmr = new_mode;
	}

	m8xx_cpm_setbrg(PORT_BRG(state->smc_scc_num), baud_rate);

	restore_flags(flags);
}

static void rs_8xx_put_char(struct tty_struct *tty, unsigned char ch)
{
	ser_info_t *info = (ser_info_t *)tty->driver_data;
	volatile cbd_t	*bdp;
	unsigned char *cp;
	unsigned long flags;

	if (serial_paranoia_check(info, tty->device, "rs_put_char"))
		return;

	if (!tty)
		return;

	local_irq_save(flags);
	bdp = info->tx_cur;
	/* Get next BD.
	*/
	if (bdp->cbd_sc & BD_SC_WRAP)
		info->tx_cur = info->tx_bd_base;
	else
		info->tx_cur = (cbd_t *)bdp + 1;
	local_irq_restore(flags);

	while (bdp->cbd_sc & BD_SC_READY);

	cp = info->tx_va_base + ((bdp - info->tx_bd_base) * TX_BUF_SIZE);
	*cp = ch;
	bdp->cbd_datlen = 1;
	bdp->cbd_sc |= BD_SC_READY;

}

static int rs_8xx_write(struct tty_struct * tty, int from_user,
		    const unsigned char *buf, int count)
{
	int	c, ret = 0;
	ser_info_t *info = (ser_info_t *)tty->driver_data;
	volatile cbd_t *bdp;
	unsigned char	*cp;
	unsigned long flags;

#ifdef CONFIG_KGDB_CONSOLE
        /* Try to let stub handle output. Returns true if it did. */
        if (kgdb_output_string(buf, count))
            return ret;
#endif

	if (serial_paranoia_check(info, tty->device, "rs_write"))
		return 0;

	if (!tty)
		return 0;

	while (1) {
		c = MIN(count, TX_BUF_SIZE);

		if (c <= 0)
			break;

		local_irq_save(flags);
		bdp = info->tx_cur;
		if (bdp->cbd_sc & BD_SC_READY) {
			info->flags |= TX_WAKEUP;
			local_irq_restore(flags);
			break;
		}
		/* Get next BD.
		 */
		if (bdp->cbd_sc & BD_SC_WRAP)
			info->tx_cur = info->tx_bd_base;
		else
			info->tx_cur = (cbd_t *)bdp + 1;
		local_irq_restore(flags);

		cp = info->tx_va_base + ((bdp - info->tx_bd_base) *
				TX_BUF_SIZE);
		if (from_user)
			c -= copy_from_user((void *)cp, buf, c);
		else
			memcpy((void *)cp, buf, c);

		if (c) {
			bdp->cbd_datlen = c;
			bdp->cbd_sc |= BD_SC_READY;
		} else {
			/* Need to TX at least 1 char to keep CPM sane */
			bdp->cbd_datlen = 1;
			*cp = 0;
			bdp->cbd_sc |= BD_SC_READY;

			if (!ret)
				ret = -EFAULT;
			break;
		}
		buf += c;
		count -= c;
		ret += c;
	}
	return ret;
}

static int rs_8xx_write_room(struct tty_struct *tty)
{
	ser_info_t *info = (ser_info_t *)tty->driver_data;
	int	ret;

	if (serial_paranoia_check(info, tty->device, "rs_write_room"))
		return 0;

	if ((info->tx_cur->cbd_sc & BD_SC_READY) == 0) {
		info->flags &= ~TX_WAKEUP;
		ret = TX_BUF_SIZE;
	}
	else {
		info->flags |= TX_WAKEUP;
		ret = 0;
	}
	return ret;
}

/* I could track this with transmit counters....maybe later.
*/
static int rs_8xx_chars_in_buffer(struct tty_struct *tty)
{
	ser_info_t *info = (ser_info_t *)tty->driver_data;

	if (serial_paranoia_check(info, tty->device, "rs_chars_in_buffer"))
		return 0;
	return 0;
}

static void rs_8xx_flush_buffer(struct tty_struct *tty)
{
	ser_info_t *info = (ser_info_t *)tty->driver_data;

	if (serial_paranoia_check(info, tty->device, "rs_flush_buffer"))
		return;

	/* There is nothing to "flush", whatever we gave the CPM
	 * is on its way out.
	 */
	tty_wakeup(tty);
	info->flags &= ~TX_WAKEUP;
}

/*
 * This function is used to send a high-priority XON/XOFF character to
 * the device
 */
static void rs_8xx_send_xchar(struct tty_struct *tty, char ch)
{
	volatile cbd_t	*bdp;
	unsigned char	*cp;
	unsigned long flags;

	ser_info_t *info = (ser_info_t *)tty->driver_data;

	if (serial_paranoia_check(info, tty->device, "rs_send_char"))
		return;

	local_irq_save(flags);
	bdp = info->tx_cur;
	/* Get next BD.
	*/
	if (bdp->cbd_sc & BD_SC_WRAP)
		info->tx_cur = info->tx_bd_base;
	else
		info->tx_cur = (cbd_t *)bdp + 1;
	local_irq_restore(flags);
	while (bdp->cbd_sc & BD_SC_READY);

	cp = info->tx_va_base + ((bdp - info->tx_bd_base) * TX_BUF_SIZE);
	*cp = ch;
	bdp->cbd_datlen = 1;
	bdp->cbd_sc |= BD_SC_READY;
}

/*
 * ------------------------------------------------------------
 * rs_throttle()
 *
 * This routine is called by the upper-layer tty layer to signal that
 * incoming characters should be throttled.
 * ------------------------------------------------------------
 */
static void rs_8xx_throttle(struct tty_struct * tty)
{
	ser_info_t *info = (ser_info_t *)tty->driver_data;
#ifdef SERIAL_DEBUG_THROTTLE
	char	buf[64];

	printk("throttle %s: %d....\n", _tty_name(tty, buf),
	       tty->ldisc.chars_in_buffer(tty));
#endif

	if (serial_paranoia_check(info, tty->device, "rs_throttle"))
		return;

	if (I_IXOFF(tty))
		rs_8xx_send_xchar(tty, STOP_CHAR(tty));

#ifdef modem_control
	if (tty->termios->c_cflag & CRTSCTS)
		info->MCR &= ~UART_MCR_RTS;

	cli();
	serial_out(info, UART_MCR, info->MCR);
	sti();
#endif
}

static void rs_8xx_unthrottle(struct tty_struct * tty)
{
	ser_info_t *info = (ser_info_t *)tty->driver_data;
#ifdef SERIAL_DEBUG_THROTTLE
	char	buf[64];

	printk("unthrottle %s: %d....\n", _tty_name(tty, buf),
	       tty->ldisc.chars_in_buffer(tty));
#endif

	if (serial_paranoia_check(info, tty->device, "rs_unthrottle"))
		return;

	if (I_IXOFF(tty)) {
		if (info->x_char)
			info->x_char = 0;
		else
			rs_8xx_send_xchar(tty, START_CHAR(tty));
	}
#ifdef modem_control
	if (tty->termios->c_cflag & CRTSCTS)
		info->MCR |= UART_MCR_RTS;
	cli();
	serial_out(info, UART_MCR, info->MCR);
	sti();
#endif
}

/*
 * ------------------------------------------------------------
 * rs_ioctl() and friends
 * ------------------------------------------------------------
 */

#ifdef maybe
/*
 * get_lsr_info - get line status register info
 *
 * Purpose: Let user call ioctl() to get info when the UART physically
 * 	    is emptied.  On bus types like RS485, the transmitter must
 * 	    release the bus after transmitting. This must be done when
 * 	    the transmit shift register is empty, not be done when the
 * 	    transmit holding register is empty.  This functionality
 * 	    allows an RS485 driver to be written in user space.
 */
static int get_lsr_info(struct async_struct * info, unsigned int *value)
{
	unsigned char status;
	unsigned int result;

	cli();
	status = serial_in(info, UART_LSR);
	sti();
	result = ((status & UART_LSR_TEMT) ? TIOCSER_TEMT : 0);
	return put_user(result,value);
}
#endif

static int get_modem_info(ser_info_t *info, unsigned int *value)
{
	unsigned int result = 0;
#ifdef modem_control
	unsigned char control, status;

	control = info->MCR;
	cli();
	status = serial_in(info, UART_MSR);
	sti();
	result =  ((control & UART_MCR_RTS) ? TIOCM_RTS : 0)
		| ((control & UART_MCR_DTR) ? TIOCM_DTR : 0)
#ifdef TIOCM_OUT1
		| ((control & UART_MCR_OUT1) ? TIOCM_OUT1 : 0)
		| ((control & UART_MCR_OUT2) ? TIOCM_OUT2 : 0)
#endif
		| ((status  & UART_MSR_DCD) ? TIOCM_CAR : 0)
		| ((status  & UART_MSR_RI) ? TIOCM_RNG : 0)
		| ((status  & UART_MSR_DSR) ? TIOCM_DSR : 0)
		| ((status  & UART_MSR_CTS) ? TIOCM_CTS : 0);
#endif
	return put_user(result,value);
}

static int set_modem_info(ser_info_t *info, unsigned int cmd,
			  unsigned int *value)
{
	int error;
	unsigned int arg;

	error = get_user(arg, value);
	if (error)
		return error;
#ifdef modem_control
	switch (cmd) {
	case TIOCMBIS:
		if (arg & TIOCM_RTS)
			info->MCR |= UART_MCR_RTS;
		if (arg & TIOCM_DTR)
			info->MCR |= UART_MCR_DTR;
#ifdef TIOCM_OUT1
		if (arg & TIOCM_OUT1)
			info->MCR |= UART_MCR_OUT1;
		if (arg & TIOCM_OUT2)
			info->MCR |= UART_MCR_OUT2;
#endif
		break;
	case TIOCMBIC:
		if (arg & TIOCM_RTS)
			info->MCR &= ~UART_MCR_RTS;
		if (arg & TIOCM_DTR)
			info->MCR &= ~UART_MCR_DTR;
#ifdef TIOCM_OUT1
		if (arg & TIOCM_OUT1)
			info->MCR &= ~UART_MCR_OUT1;
		if (arg & TIOCM_OUT2)
			info->MCR &= ~UART_MCR_OUT2;
#endif
		break;
	case TIOCMSET:
		info->MCR = ((info->MCR & ~(UART_MCR_RTS |
#ifdef TIOCM_OUT1
					    UART_MCR_OUT1 |
					    UART_MCR_OUT2 |
#endif
					    UART_MCR_DTR))
			     | ((arg & TIOCM_RTS) ? UART_MCR_RTS : 0)
#ifdef TIOCM_OUT1
			     | ((arg & TIOCM_OUT1) ? UART_MCR_OUT1 : 0)
			     | ((arg & TIOCM_OUT2) ? UART_MCR_OUT2 : 0)
#endif
			     | ((arg & TIOCM_DTR) ? UART_MCR_DTR : 0));
		break;
	default:
		return -EINVAL;
	}
	cli();
	serial_out(info, UART_MCR, info->MCR);
	sti();
#endif
	return 0;
}

/* Sending a break is a two step process on the SMC/SCC.  It is accomplished
 * by sending a STOP TRANSMIT command followed by a RESTART TRANSMIT
 * command.  We take advantage of the begin/end functions to make this
 * happen.
 */
static ushort	smc_chan_map[] = {
	CPM_CR_CH_SMC1,
	CPM_CR_CH_SMC2
};

static ushort	scc_chan_map[] = {
	CPM_CR_CH_SCC1,
	CPM_CR_CH_SCC2,
	CPM_CR_CH_SCC3,
	CPM_CR_CH_SCC4
};

static void begin_break(ser_info_t *info)
{
	volatile cpm8xx_t *cp;
	ushort	chan;
	int	idx;

	cp = cpmp;

	idx = PORT_NUM(info->state->smc_scc_num);
	if (PORT_IS_SCC(info->state->smc_scc_num))
		chan = scc_chan_map[idx];
	else
		chan = smc_chan_map[idx];
	cp->cp_cpcr = mk_cr_cmd(chan, CPM_CR_STOP_TX) | CPM_CR_FLG;
	while (cp->cp_cpcr & CPM_CR_FLG);
}

static void end_break(ser_info_t *info)
{
	volatile cpm8xx_t *cp;
	ushort	chan;
	int	idx;

	cp = cpmp;

	idx = PORT_NUM(info->state->smc_scc_num);
	if (PORT_IS_SCC(info->state->smc_scc_num))
		chan = scc_chan_map[idx];
	else
		chan = smc_chan_map[idx];
	cp->cp_cpcr = mk_cr_cmd(chan, CPM_CR_RESTART_TX) | CPM_CR_FLG;
	while (cp->cp_cpcr & CPM_CR_FLG);
}

/*
 * This routine sends a break character out the serial port.
 */
static void send_break(ser_info_t *info, int duration)
{
	current->state = TASK_INTERRUPTIBLE;
#ifdef SERIAL_DEBUG_SEND_BREAK
	printk("rs_send_break(%d) jiff=%lu...", duration, jiffies);
#endif
	begin_break(info);
	schedule_timeout(duration);
	end_break(info);
#ifdef SERIAL_DEBUG_SEND_BREAK
	printk("done jiffies=%lu\n", jiffies);
#endif
}


static int rs_8xx_ioctl(struct tty_struct *tty, struct file * file,
		    unsigned int cmd, unsigned long arg)
{
	int error;
	ser_info_t *info = (ser_info_t *)tty->driver_data;
	int retval;
	struct async_icount cnow;	/* kernel counter temps */
	struct serial_icounter_struct *p_cuser;	/* user space */

	if (serial_paranoia_check(info, tty->device, "rs_ioctl"))
		return -ENODEV;

	if ((cmd != TIOCMIWAIT) && (cmd != TIOCGICOUNT)) {
		if (tty->flags & (1 << TTY_IO_ERROR))
		    return -EIO;
	}

	switch (cmd) {
		case TCSBRK:	/* SVID version: non-zero arg --> no break */
			retval = tty_check_change(tty);
			if (retval)
				return retval;
			tty_wait_until_sent(tty, 0);
			if (signal_pending(current))
				return -EINTR;
			if (!arg) {
				send_break(info, HZ/4);	/* 1/4 second */
				if (signal_pending(current))
					return -EINTR;
			}
			return 0;
		case TCSBRKP:	/* support for POSIX tcsendbreak() */
			retval = tty_check_change(tty);
			if (retval)
				return retval;
			tty_wait_until_sent(tty, 0);
			if (signal_pending(current))
				return -EINTR;
			send_break(info, arg ? arg*(HZ/10) : HZ/4);
			if (signal_pending(current))
				return -EINTR;
			return 0;
		case TIOCSBRK:
			retval = tty_check_change(tty);
			if (retval)
				return retval;
			tty_wait_until_sent(tty, 0);
			begin_break(info);