ns16550.c
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/*
* 16550 serial console support.
*
* Original copied from <file:arch/ppc/boot/common/ns16550.c>
* (which had no copyright)
* Modifications: 2006 (c) MontaVista Software, Inc.
*
* Modified by: Mark A. Greer <mgreer@mvista.com>
*/
#include <stdarg.h>
#include <stddef.h>
#include "types.h"
#include "string.h"
#include "stdio.h"
#include "io.h"
#include "ops.h"
#define UART_DLL 0 /* Out: Divisor Latch Low */
#define UART_DLM 1 /* Out: Divisor Latch High */
#define UART_FCR 2 /* Out: FIFO Control Register */
#define UART_LCR 3 /* Out: Line Control Register */
#define UART_MCR 4 /* Out: Modem Control Register */
#define UART_LSR 5 /* In: Line Status Register */
#define UART_LSR_THRE 0x20 /* Transmit-hold-register empty */
#define UART_LSR_DR 0x01 /* Receiver data ready */
#define UART_MSR 6 /* In: Modem Status Register */
#define UART_SCR 7 /* I/O: Scratch Register */
static unsigned char *reg_base;
static u32 reg_shift;
static int ns16550_open(void)
{
out_8(reg_base + (UART_FCR << reg_shift), 0x06);
return 0;
}
static void ns16550_putc(unsigned char c)
{
while ((in_8(reg_base + (UART_LSR << reg_shift)) & UART_LSR_THRE) == 0);
out_8(reg_base, c);
}
static unsigned char ns16550_getc(void)
{
while ((in_8(reg_base + (UART_LSR << reg_shift)) & UART_LSR_DR) == 0);
return in_8(reg_base);
}
static u8 ns16550_tstc(void)
{
return ((in_8(reg_base + (UART_LSR << reg_shift)) & UART_LSR_DR) != 0);
}
int ns16550_console_init(void *devp, struct serial_console_data *scdp)
{
int n;
u32 reg_offset;
if (dt_get_virtual_reg(devp, (void **)®_base, 1) < 1)
return -1;
n = getprop(devp, "reg-offset", ®_offset, sizeof(reg_offset));
if (n == sizeof(reg_offset))
reg_base += reg_offset;
n = getprop(devp, "reg-shift", ®_shift, sizeof(reg_shift));
if (n != sizeof(reg_shift))
reg_shift = 0;
scdp->open = ns16550_open;
scdp->putc = ns16550_putc;
scdp->getc = ns16550_getc;
scdp->tstc = ns16550_tstc;
scdp->close = NULL;
return 0;
}