507 lines
11 KiB
C
507 lines
11 KiB
C
/*
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* Driver for the serial port on the 21285 StrongArm-110 core logic chip.
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*
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* Based on drivers/char/serial.c
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*/
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#include <linux/module.h>
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#include <linux/tty.h>
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#include <linux/ioport.h>
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#include <linux/init.h>
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#include <linux/console.h>
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#include <linux/device.h>
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#include <linux/tty_flip.h>
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#include <linux/serial_core.h>
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#include <linux/serial.h>
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#include <linux/io.h>
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#include <asm/irq.h>
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#include <asm/mach-types.h>
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#include <asm/system_info.h>
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#include <asm/hardware/dec21285.h>
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#include <mach/hardware.h>
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#define BAUD_BASE (mem_fclk_21285/64)
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#define SERIAL_21285_NAME "ttyFB"
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#define SERIAL_21285_MAJOR 204
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#define SERIAL_21285_MINOR 4
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#define RXSTAT_DUMMY_READ 0x80000000
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#define RXSTAT_FRAME (1 << 0)
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#define RXSTAT_PARITY (1 << 1)
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#define RXSTAT_OVERRUN (1 << 2)
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#define RXSTAT_ANYERR (RXSTAT_FRAME|RXSTAT_PARITY|RXSTAT_OVERRUN)
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#define H_UBRLCR_BREAK (1 << 0)
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#define H_UBRLCR_PARENB (1 << 1)
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#define H_UBRLCR_PAREVN (1 << 2)
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#define H_UBRLCR_STOPB (1 << 3)
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#define H_UBRLCR_FIFO (1 << 4)
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static const char serial21285_name[] = "Footbridge UART";
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#define tx_enabled(port) ((port)->unused[0])
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#define rx_enabled(port) ((port)->unused[1])
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/*
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* The documented expression for selecting the divisor is:
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* BAUD_BASE / baud - 1
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* However, typically BAUD_BASE is not divisible by baud, so
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* we want to select the divisor that gives us the minimum
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* error. Therefore, we want:
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* int(BAUD_BASE / baud - 0.5) ->
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* int(BAUD_BASE / baud - (baud >> 1) / baud) ->
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* int((BAUD_BASE - (baud >> 1)) / baud)
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*/
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static void serial21285_stop_tx(struct uart_port *port)
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{
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if (tx_enabled(port)) {
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disable_irq_nosync(IRQ_CONTX);
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tx_enabled(port) = 0;
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}
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}
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static void serial21285_start_tx(struct uart_port *port)
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{
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if (!tx_enabled(port)) {
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enable_irq(IRQ_CONTX);
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tx_enabled(port) = 1;
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}
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}
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static void serial21285_stop_rx(struct uart_port *port)
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{
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if (rx_enabled(port)) {
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disable_irq_nosync(IRQ_CONRX);
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rx_enabled(port) = 0;
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}
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}
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static irqreturn_t serial21285_rx_chars(int irq, void *dev_id)
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{
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struct uart_port *port = dev_id;
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unsigned int status, ch, flag, rxs, max_count = 256;
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status = *CSR_UARTFLG;
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while (!(status & 0x10) && max_count--) {
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ch = *CSR_UARTDR;
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flag = TTY_NORMAL;
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port->icount.rx++;
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rxs = *CSR_RXSTAT | RXSTAT_DUMMY_READ;
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if (unlikely(rxs & RXSTAT_ANYERR)) {
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if (rxs & RXSTAT_PARITY)
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port->icount.parity++;
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else if (rxs & RXSTAT_FRAME)
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port->icount.frame++;
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if (rxs & RXSTAT_OVERRUN)
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port->icount.overrun++;
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rxs &= port->read_status_mask;
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if (rxs & RXSTAT_PARITY)
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flag = TTY_PARITY;
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else if (rxs & RXSTAT_FRAME)
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flag = TTY_FRAME;
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}
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uart_insert_char(port, rxs, RXSTAT_OVERRUN, ch, flag);
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status = *CSR_UARTFLG;
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}
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tty_flip_buffer_push(&port->state->port);
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return IRQ_HANDLED;
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}
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static irqreturn_t serial21285_tx_chars(int irq, void *dev_id)
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{
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struct uart_port *port = dev_id;
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struct circ_buf *xmit = &port->state->xmit;
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int count = 256;
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if (port->x_char) {
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*CSR_UARTDR = port->x_char;
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port->icount.tx++;
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port->x_char = 0;
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goto out;
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}
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if (uart_circ_empty(xmit) || uart_tx_stopped(port)) {
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serial21285_stop_tx(port);
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goto out;
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}
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do {
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*CSR_UARTDR = xmit->buf[xmit->tail];
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xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
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port->icount.tx++;
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if (uart_circ_empty(xmit))
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break;
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} while (--count > 0 && !(*CSR_UARTFLG & 0x20));
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if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
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uart_write_wakeup(port);
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if (uart_circ_empty(xmit))
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serial21285_stop_tx(port);
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out:
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return IRQ_HANDLED;
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}
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static unsigned int serial21285_tx_empty(struct uart_port *port)
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{
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return (*CSR_UARTFLG & 8) ? 0 : TIOCSER_TEMT;
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}
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/* no modem control lines */
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static unsigned int serial21285_get_mctrl(struct uart_port *port)
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{
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return TIOCM_CAR | TIOCM_DSR | TIOCM_CTS;
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}
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static void serial21285_set_mctrl(struct uart_port *port, unsigned int mctrl)
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{
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}
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static void serial21285_break_ctl(struct uart_port *port, int break_state)
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{
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unsigned long flags;
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unsigned int h_lcr;
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spin_lock_irqsave(&port->lock, flags);
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h_lcr = *CSR_H_UBRLCR;
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if (break_state)
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h_lcr |= H_UBRLCR_BREAK;
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else
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h_lcr &= ~H_UBRLCR_BREAK;
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*CSR_H_UBRLCR = h_lcr;
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spin_unlock_irqrestore(&port->lock, flags);
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}
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static int serial21285_startup(struct uart_port *port)
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{
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int ret;
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tx_enabled(port) = 1;
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rx_enabled(port) = 1;
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ret = request_irq(IRQ_CONRX, serial21285_rx_chars, 0,
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serial21285_name, port);
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if (ret == 0) {
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ret = request_irq(IRQ_CONTX, serial21285_tx_chars, 0,
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serial21285_name, port);
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if (ret)
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free_irq(IRQ_CONRX, port);
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}
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return ret;
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}
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static void serial21285_shutdown(struct uart_port *port)
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{
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free_irq(IRQ_CONTX, port);
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free_irq(IRQ_CONRX, port);
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}
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static void
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serial21285_set_termios(struct uart_port *port, struct ktermios *termios,
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struct ktermios *old)
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{
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unsigned long flags;
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unsigned int baud, quot, h_lcr, b;
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/*
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* We don't support modem control lines.
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*/
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termios->c_cflag &= ~(HUPCL | CRTSCTS | CMSPAR);
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termios->c_cflag |= CLOCAL;
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/*
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* We don't support BREAK character recognition.
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*/
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termios->c_iflag &= ~(IGNBRK | BRKINT);
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/*
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* Ask the core to calculate the divisor for us.
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*/
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baud = uart_get_baud_rate(port, termios, old, 0, port->uartclk/16);
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quot = uart_get_divisor(port, baud);
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b = port->uartclk / (16 * quot);
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tty_termios_encode_baud_rate(termios, b, b);
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switch (termios->c_cflag & CSIZE) {
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case CS5:
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h_lcr = 0x00;
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break;
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case CS6:
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h_lcr = 0x20;
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break;
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case CS7:
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h_lcr = 0x40;
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break;
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default: /* CS8 */
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h_lcr = 0x60;
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break;
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}
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if (termios->c_cflag & CSTOPB)
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h_lcr |= H_UBRLCR_STOPB;
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if (termios->c_cflag & PARENB) {
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h_lcr |= H_UBRLCR_PARENB;
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if (!(termios->c_cflag & PARODD))
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h_lcr |= H_UBRLCR_PAREVN;
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}
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if (port->fifosize)
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h_lcr |= H_UBRLCR_FIFO;
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spin_lock_irqsave(&port->lock, flags);
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/*
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* Update the per-port timeout.
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*/
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uart_update_timeout(port, termios->c_cflag, baud);
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/*
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* Which character status flags are we interested in?
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*/
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port->read_status_mask = RXSTAT_OVERRUN;
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if (termios->c_iflag & INPCK)
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port->read_status_mask |= RXSTAT_FRAME | RXSTAT_PARITY;
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/*
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* Which character status flags should we ignore?
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*/
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port->ignore_status_mask = 0;
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if (termios->c_iflag & IGNPAR)
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port->ignore_status_mask |= RXSTAT_FRAME | RXSTAT_PARITY;
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if (termios->c_iflag & IGNBRK && termios->c_iflag & IGNPAR)
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port->ignore_status_mask |= RXSTAT_OVERRUN;
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/*
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* Ignore all characters if CREAD is not set.
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*/
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if ((termios->c_cflag & CREAD) == 0)
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port->ignore_status_mask |= RXSTAT_DUMMY_READ;
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quot -= 1;
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*CSR_UARTCON = 0;
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*CSR_L_UBRLCR = quot & 0xff;
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*CSR_M_UBRLCR = (quot >> 8) & 0x0f;
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*CSR_H_UBRLCR = h_lcr;
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*CSR_UARTCON = 1;
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spin_unlock_irqrestore(&port->lock, flags);
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}
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static const char *serial21285_type(struct uart_port *port)
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{
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return port->type == PORT_21285 ? "DC21285" : NULL;
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}
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static void serial21285_release_port(struct uart_port *port)
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{
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release_mem_region(port->mapbase, 32);
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}
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static int serial21285_request_port(struct uart_port *port)
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{
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return request_mem_region(port->mapbase, 32, serial21285_name)
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!= NULL ? 0 : -EBUSY;
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}
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static void serial21285_config_port(struct uart_port *port, int flags)
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{
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if (flags & UART_CONFIG_TYPE && serial21285_request_port(port) == 0)
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port->type = PORT_21285;
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}
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/*
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* verify the new serial_struct (for TIOCSSERIAL).
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*/
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static int serial21285_verify_port(struct uart_port *port, struct serial_struct *ser)
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{
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int ret = 0;
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if (ser->type != PORT_UNKNOWN && ser->type != PORT_21285)
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ret = -EINVAL;
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if (ser->irq <= 0)
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ret = -EINVAL;
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if (ser->baud_base != port->uartclk / 16)
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ret = -EINVAL;
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return ret;
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}
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static struct uart_ops serial21285_ops = {
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.tx_empty = serial21285_tx_empty,
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.get_mctrl = serial21285_get_mctrl,
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.set_mctrl = serial21285_set_mctrl,
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.stop_tx = serial21285_stop_tx,
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.start_tx = serial21285_start_tx,
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.stop_rx = serial21285_stop_rx,
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.break_ctl = serial21285_break_ctl,
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.startup = serial21285_startup,
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.shutdown = serial21285_shutdown,
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.set_termios = serial21285_set_termios,
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.type = serial21285_type,
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.release_port = serial21285_release_port,
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.request_port = serial21285_request_port,
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.config_port = serial21285_config_port,
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.verify_port = serial21285_verify_port,
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};
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static struct uart_port serial21285_port = {
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.mapbase = 0x42000160,
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.iotype = UPIO_MEM,
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.irq = 0,
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.fifosize = 16,
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.ops = &serial21285_ops,
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.flags = UPF_BOOT_AUTOCONF,
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};
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static void serial21285_setup_ports(void)
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{
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serial21285_port.uartclk = mem_fclk_21285 / 4;
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}
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#ifdef CONFIG_SERIAL_21285_CONSOLE
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static void serial21285_console_putchar(struct uart_port *port, int ch)
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{
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while (*CSR_UARTFLG & 0x20)
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barrier();
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*CSR_UARTDR = ch;
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}
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static void
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serial21285_console_write(struct console *co, const char *s,
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unsigned int count)
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{
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uart_console_write(&serial21285_port, s, count, serial21285_console_putchar);
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}
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static void __init
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serial21285_get_options(struct uart_port *port, int *baud,
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int *parity, int *bits)
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{
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if (*CSR_UARTCON == 1) {
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unsigned int tmp;
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tmp = *CSR_H_UBRLCR;
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switch (tmp & 0x60) {
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case 0x00:
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*bits = 5;
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break;
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case 0x20:
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*bits = 6;
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break;
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case 0x40:
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*bits = 7;
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break;
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default:
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case 0x60:
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*bits = 8;
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break;
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}
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if (tmp & H_UBRLCR_PARENB) {
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*parity = 'o';
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if (tmp & H_UBRLCR_PAREVN)
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*parity = 'e';
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}
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tmp = *CSR_L_UBRLCR | (*CSR_M_UBRLCR << 8);
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*baud = port->uartclk / (16 * (tmp + 1));
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}
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}
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static int __init serial21285_console_setup(struct console *co, char *options)
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{
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struct uart_port *port = &serial21285_port;
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int baud = 9600;
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int bits = 8;
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int parity = 'n';
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int flow = 'n';
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if (machine_is_personal_server())
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baud = 57600;
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/*
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* Check whether an invalid uart number has been specified, and
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* if so, search for the first available port that does have
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* console support.
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*/
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if (options)
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uart_parse_options(options, &baud, &parity, &bits, &flow);
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else
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serial21285_get_options(port, &baud, &parity, &bits);
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return uart_set_options(port, co, baud, parity, bits, flow);
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}
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static struct uart_driver serial21285_reg;
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static struct console serial21285_console =
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{
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.name = SERIAL_21285_NAME,
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.write = serial21285_console_write,
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.device = uart_console_device,
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.setup = serial21285_console_setup,
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.flags = CON_PRINTBUFFER,
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.index = -1,
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.data = &serial21285_reg,
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};
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static int __init rs285_console_init(void)
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{
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serial21285_setup_ports();
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register_console(&serial21285_console);
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return 0;
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}
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console_initcall(rs285_console_init);
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#define SERIAL_21285_CONSOLE &serial21285_console
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#else
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#define SERIAL_21285_CONSOLE NULL
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#endif
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static struct uart_driver serial21285_reg = {
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.owner = THIS_MODULE,
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.driver_name = "ttyFB",
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.dev_name = "ttyFB",
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.major = SERIAL_21285_MAJOR,
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.minor = SERIAL_21285_MINOR,
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.nr = 1,
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.cons = SERIAL_21285_CONSOLE,
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};
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static int __init serial21285_init(void)
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{
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int ret;
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printk(KERN_INFO "Serial: 21285 driver\n");
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serial21285_setup_ports();
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ret = uart_register_driver(&serial21285_reg);
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if (ret == 0)
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uart_add_one_port(&serial21285_reg, &serial21285_port);
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return ret;
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}
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static void __exit serial21285_exit(void)
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{
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uart_remove_one_port(&serial21285_reg, &serial21285_port);
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uart_unregister_driver(&serial21285_reg);
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}
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module_init(serial21285_init);
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module_exit(serial21285_exit);
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MODULE_LICENSE("GPL");
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MODULE_DESCRIPTION("Intel Footbridge (21285) serial driver");
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MODULE_ALIAS_CHARDEV(SERIAL_21285_MAJOR, SERIAL_21285_MINOR);
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