static void neo_param()

in serial/jsm/jsm_neo.c [925:1090]

• 126 lines of code
• 26 McCabe index (conditional complexity)

static void neo_param(struct jsm_channel *ch)
{
	u8 lcr = 0;
	u8 uart_lcr, ier;
	u32 baud;
	int quot;
	struct jsm_board *bd;

	bd = ch->ch_bd;
	if (!bd)
		return;

	/*
	 * If baud rate is zero, flush queues, and set mval to drop DTR.
	 */
	if ((ch->ch_c_cflag & (CBAUD)) == 0) {
		ch->ch_r_head = ch->ch_r_tail = 0;
		ch->ch_e_head = ch->ch_e_tail = 0;

		neo_flush_uart_write(ch);
		neo_flush_uart_read(ch);

		ch->ch_flags |= (CH_BAUD0);
		ch->ch_mostat &= ~(UART_MCR_RTS | UART_MCR_DTR);
		neo_assert_modem_signals(ch);
		return;

	} else {
		int i;
		unsigned int cflag;
		static struct {
			unsigned int rate;
			unsigned int cflag;
		} baud_rates[] = {
			{ 921600, B921600 },
			{ 460800, B460800 },
			{ 230400, B230400 },
			{ 115200, B115200 },
			{  57600, B57600  },
			{  38400, B38400  },
			{  19200, B19200  },
			{   9600, B9600   },
			{   4800, B4800   },
			{   2400, B2400   },
			{   1200, B1200   },
			{    600, B600    },
			{    300, B300    },
			{    200, B200    },
			{    150, B150    },
			{    134, B134    },
			{    110, B110    },
			{     75, B75     },
			{     50, B50     },
		};

		cflag = C_BAUD(ch->uart_port.state->port.tty);
		baud = 9600;
		for (i = 0; i < ARRAY_SIZE(baud_rates); i++) {
			if (baud_rates[i].cflag == cflag) {
				baud = baud_rates[i].rate;
				break;
			}
		}

		if (ch->ch_flags & CH_BAUD0)
			ch->ch_flags &= ~(CH_BAUD0);
	}

	if (ch->ch_c_cflag & PARENB)
		lcr |= UART_LCR_PARITY;

	if (!(ch->ch_c_cflag & PARODD))
		lcr |= UART_LCR_EPAR;

	/*
	 * Not all platforms support mark/space parity,
	 * so this will hide behind an ifdef.
	 */
#ifdef CMSPAR
	if (ch->ch_c_cflag & CMSPAR)
		lcr |= UART_LCR_SPAR;
#endif

	if (ch->ch_c_cflag & CSTOPB)
		lcr |= UART_LCR_STOP;

	switch (ch->ch_c_cflag & CSIZE) {
	case CS5:
		lcr |= UART_LCR_WLEN5;
		break;
	case CS6:
		lcr |= UART_LCR_WLEN6;
		break;
	case CS7:
		lcr |= UART_LCR_WLEN7;
		break;
	case CS8:
	default:
		lcr |= UART_LCR_WLEN8;
	break;
	}

	ier = readb(&ch->ch_neo_uart->ier);
	uart_lcr = readb(&ch->ch_neo_uart->lcr);

	quot = ch->ch_bd->bd_dividend / baud;

	if (quot != 0) {
		writeb(UART_LCR_DLAB, &ch->ch_neo_uart->lcr);
		writeb((quot & 0xff), &ch->ch_neo_uart->txrx);
		writeb((quot >> 8), &ch->ch_neo_uart->ier);
		writeb(lcr, &ch->ch_neo_uart->lcr);
	}

	if (uart_lcr != lcr)
		writeb(lcr, &ch->ch_neo_uart->lcr);

	if (ch->ch_c_cflag & CREAD)
		ier |= (UART_IER_RDI | UART_IER_RLSI);

	ier |= (UART_IER_THRI | UART_IER_MSI);

	writeb(ier, &ch->ch_neo_uart->ier);

	/* Set new start/stop chars */
	neo_set_new_start_stop_chars(ch);

	if (ch->ch_c_cflag & CRTSCTS)
		neo_set_cts_flow_control(ch);
	else if (ch->ch_c_iflag & IXON) {
		/* If start/stop is set to disable, then we should disable flow control */
		if ((ch->ch_startc == __DISABLED_CHAR) || (ch->ch_stopc == __DISABLED_CHAR))
			neo_set_no_output_flow_control(ch);
		else
			neo_set_ixon_flow_control(ch);
	}
	else
		neo_set_no_output_flow_control(ch);

	if (ch->ch_c_cflag & CRTSCTS)
		neo_set_rts_flow_control(ch);
	else if (ch->ch_c_iflag & IXOFF) {
		/* If start/stop is set to disable, then we should disable flow control */
		if ((ch->ch_startc == __DISABLED_CHAR) || (ch->ch_stopc == __DISABLED_CHAR))
			neo_set_no_input_flow_control(ch);
		else
			neo_set_ixoff_flow_control(ch);
	}
	else
		neo_set_no_input_flow_control(ch);
	/*
	 * Adjust the RX FIFO Trigger level if baud is less than 9600.
	 * Not exactly elegant, but this is needed because of the Exar chip's
	 * delay on firing off the RX FIFO interrupt on slower baud rates.
	 */
	if (baud < 9600) {
		writeb(1, &ch->ch_neo_uart->rfifo);
		ch->ch_r_tlevel = 1;
	}

	neo_assert_modem_signals(ch);

	/* Get current status of the modem signals now */
	neo_parse_modem(ch, readb(&ch->ch_neo_uart->msr));
	return;
}