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|
/*
* linux/drivers/serial/21285.c
*
* Driver for the serial port on the 21285 StrongArm-110 core logic chip.
*
* Based on drivers/char/serial.c
*/
#include <linux/module.h>
#include <linux/tty.h>
#include <linux/ioport.h>
#include <linux/init.h>
#include <linux/console.h>
#include <linux/device.h>
#include <linux/tty_flip.h>
#include <linux/serial_core.h>
#include <linux/serial.h>
#include <asm/io.h>
#include <asm/irq.h>
#include <asm/mach-types.h>
#include <asm/hardware/dec21285.h>
#include <mach/hardware.h>
#define BAUD_BASE (mem_fclk_21285/64)
#define SERIAL_21285_NAME "ttyFB"
#define SERIAL_21285_MAJOR 204
#define SERIAL_21285_MINOR 4
#define RXSTAT_DUMMY_READ 0x80000000
#define RXSTAT_FRAME (1 << 0)
#define RXSTAT_PARITY (1 << 1)
#define RXSTAT_OVERRUN (1 << 2)
#define RXSTAT_ANYERR (RXSTAT_FRAME|RXSTAT_PARITY|RXSTAT_OVERRUN)
#define H_UBRLCR_BREAK (1 << 0)
#define H_UBRLCR_PARENB (1 << 1)
#define H_UBRLCR_PAREVN (1 << 2)
#define H_UBRLCR_STOPB (1 << 3)
#define H_UBRLCR_FIFO (1 << 4)
static const char serial21285_name[] = "Footbridge UART";
#define tx_enabled(port) ((port)->unused[0])
#define rx_enabled(port) ((port)->unused[1])
/*
* The documented expression for selecting the divisor is:
* BAUD_BASE / baud - 1
* However, typically BAUD_BASE is not divisible by baud, so
* we want to select the divisor that gives us the minimum
* error. Therefore, we want:
* int(BAUD_BASE / baud - 0.5) ->
* int(BAUD_BASE / baud - (baud >> 1) / baud) ->
* int((BAUD_BASE - (baud >> 1)) / baud)
*/
static void serial21285_stop_tx(struct uart_port *port)
{
if (tx_enabled(port)) {
disable_irq(IRQ_CONTX);
tx_enabled(port) = 0;
}
}
static void serial21285_start_tx(struct uart_port *port)
{
if (!tx_enabled(port)) {
enable_irq(IRQ_CONTX);
tx_enabled(port) = 1;
}
}
static void serial21285_stop_rx(struct uart_port *port)
{
if (rx_enabled(port)) {
disable_irq(IRQ_CONRX);
rx_enabled(port) = 0;
}
}
static void serial21285_enable_ms(struct uart_port *port)
{
}
static irqreturn_t serial21285_rx_chars(int irq, void *dev_id)
{
struct uart_port *port = dev_id;
struct tty_struct *tty = port->info->port.tty;
unsigned int status, ch, flag, rxs, max_count = 256;
status = *CSR_UARTFLG;
while (!(status & 0x10) && max_count--) {
ch = *CSR_UARTDR;
flag = TTY_NORMAL;
port->icount.rx++;
rxs = *CSR_RXSTAT | RXSTAT_DUMMY_READ;
if (unlikely(rxs & RXSTAT_ANYERR)) {
if (rxs & RXSTAT_PARITY)
port->icount.parity++;
else if (rxs & RXSTAT_FRAME)
port->icount.frame++;
if (rxs & RXSTAT_OVERRUN)
port->icount.overrun++;
rxs &= port->read_status_mask;
if (rxs & RXSTAT_PARITY)
flag = TTY_PARITY;
else if (rxs & RXSTAT_FRAME)
flag = TTY_FRAME;
}
uart_insert_char(port, rxs, RXSTAT_OVERRUN, ch, flag);
status = *CSR_UARTFLG;
}
tty_flip_buffer_push(tty);
return IRQ_HANDLED;
}
static irqreturn_t serial21285_tx_chars(int irq, void *dev_id)
{
struct uart_port *port = dev_id;
struct circ_buf *xmit = &port->info->xmit;
int count = 256;
if (port->x_char) {
*CSR_UARTDR = port->x_char;
port->icount.tx++;
port->x_char = 0;
goto out;
}
if (uart_circ_empty(xmit) || uart_tx_stopped(port)) {
serial21285_stop_tx(port);
goto out;
}
do {
*CSR_UARTDR = xmit->buf[xmit->tail];
xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
port->icount.tx++;
if (uart_circ_empty(xmit))
break;
} while (--count > 0 && !(*CSR_UARTFLG & 0x20));
if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
uart_write_wakeup(port);
if (uart_circ_empty(xmit))
serial21285_stop_tx(port);
out:
return IRQ_HANDLED;
}
static unsigned int serial21285_tx_empty(struct uart_port *port)
{
return (*CSR_UARTFLG & 8) ? 0 : TIOCSER_TEMT;
}
/* no modem control lines */
static unsigned int serial21285_get_mctrl(struct uart_port *port)
{
return TIOCM_CAR | TIOCM_DSR | TIOCM_CTS;
}
static void serial21285_set_mctrl(struct uart_port *port, unsigned int mctrl)
{
}
static void serial21285_break_ctl(struct uart_port *port, int break_state)
{
unsigned long flags;
unsigned int h_lcr;
spin_lock_irqsave(&port->lock, flags);
h_lcr = *CSR_H_UBRLCR;
if (break_state)
h_lcr |= H_UBRLCR_BREAK;
else
h_lcr &= ~H_UBRLCR_BREAK;
*CSR_H_UBRLCR = h_lcr;
spin_unlock_irqrestore(&port->lock, flags);
}
static int serial21285_startup(struct uart_port *port)
{
int ret;
tx_enabled(port) = 1;
rx_enabled(port) = 1;
ret = request_irq(IRQ_CONRX, serial21285_rx_chars, 0,
serial21285_name, port);
if (ret == 0) {
ret = request_irq(IRQ_CONTX, serial21285_tx_chars, 0,
serial21285_name, port);
if (ret)
free_irq(IRQ_CONRX, port);
}
return ret;
}
static void serial21285_shutdown(struct uart_port *port)
{
free_irq(IRQ_CONTX, port);
free_irq(IRQ_CONRX, port);
}
static void
serial21285_set_termios(struct uart_port *port, struct ktermios *termios,
struct ktermios *old)
{
unsigned long flags;
unsigned int baud, quot, h_lcr;
/*
* We don't support modem control lines.
*/
termios->c_cflag &= ~(HUPCL | CRTSCTS | CMSPAR);
termios->c_cflag |= CLOCAL;
/*
* We don't support BREAK character recognition.
*/
termios->c_iflag &= ~(IGNBRK | BRKINT);
/*
* Ask the core to calculate the divisor for us.
*/
baud = uart_get_baud_rate(port, termios, old, 0, port->uartclk/16);
quot = uart_get_divisor(port, baud);
if (port->info && port->info->port.tty) {
struct tty_struct *tty = port->info->port.tty;
unsigned int b = port->uartclk / (16 * quot);
tty_encode_baud_rate(tty, b, b);
}
switch (termios->c_cflag & CSIZE) {
case CS5:
h_lcr = 0x00;
break;
case CS6:
h_lcr = 0x20;
break;
case CS7:
h_lcr = 0x40;
break;
default: /* CS8 */
h_lcr = 0x60;
break;
}
if (termios->c_cflag & CSTOPB)
h_lcr |= H_UBRLCR_STOPB;
if (termios->c_cflag & PARENB) {
h_lcr |= H_UBRLCR_PARENB;
if
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