LXR linux/arch/powerpc/boot/ns16550.c

   1/*
   2 * 16550 serial console support.
   3 *
   4 * Original copied from <file:arch/ppc/boot/common/ns16550.c>
   5 * (which had no copyright)
   6 * Modifications: 2006 (c) MontaVista Software, Inc.
   7 *
   8 * Modified by: Mark A. Greer <mgreer@mvista.com>
   9 */
  10#include <stdarg.h>
  11#include <stddef.h>
  12#include "types.h"
  13#include "string.h"
  14#include "stdio.h"
  15#include "io.h"
  16#include "ops.h"
  17
  18#define UART_DLL        0       /* Out: Divisor Latch Low */
  19#define UART_DLM        1       /* Out: Divisor Latch High */
  20#define UART_FCR        2       /* Out: FIFO Control Register */
  21#define UART_LCR        3       /* Out: Line Control Register */
  22#define UART_MCR        4       /* Out: Modem Control Register */
  23#define UART_LSR        5       /* In:  Line Status Register */
  24#define UART_LSR_THRE   0x20    /* Transmit-hold-register empty */
  25#define UART_LSR_DR     0x01    /* Receiver data ready */
  26#define UART_MSR        6       /* In:  Modem Status Register */
  27#define UART_SCR        7       /* I/O: Scratch Register */
  28
  29static unsigned char *reg_base;
  30static u32 reg_shift;
  31
  32static int ns16550_open(void)
  33{
  34        out_8(reg_base + (UART_FCR << reg_shift), 0x06);
  35        return 0;
  36}
  37
  38static void ns16550_putc(unsigned char c)
  39{
  40        while ((in_8(reg_base + (UART_LSR << reg_shift)) & UART_LSR_THRE) == 0);
  41        out_8(reg_base, c);
  42}
  43
  44static unsigned char ns16550_getc(void)
  45{
  46        while ((in_8(reg_base + (UART_LSR << reg_shift)) & UART_LSR_DR) == 0);
  47        return in_8(reg_base);
  48}
  49
  50static u8 ns16550_tstc(void)
  51{
  52        return ((in_8(reg_base + (UART_LSR << reg_shift)) & UART_LSR_DR) != 0);
  53}
  54
  55int ns16550_console_init(void *devp, struct serial_console_data *scdp)
  56{
  57        int n;
  58        u32 reg_offset;
  59
  60        if (dt_get_virtual_reg(devp, (void **)&reg_base, 1) < 1)
  61                return -1;
  62
  63        n = getprop(devp, "reg-offset", &reg_offset, sizeof(reg_offset));
  64        if (n == sizeof(reg_offset))
  65                reg_base += reg_offset;
  66
  67        n = getprop(devp, "reg-shift", &reg_shift, sizeof(reg_shift));
  68        if (n != sizeof(reg_shift))
  69                reg_shift = 0;
  70
  71        scdp->open = ns16550_open;
  72        scdp->putc = ns16550_putc;
  73        scdp->getc = ns16550_getc;
  74        scdp->tstc = ns16550_tstc;
  75        scdp->close = NULL;
  76
  77        return 0;
  78}
  79