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
  29 static unsigned char *reg_base;
  30 static u32 reg_shift;
  31
  32 static int ns16550_open(void)
  33 {
  34         out_8(reg_base + (UART_FCR << reg_shift), 0x06);
  35         return 0;
  36 }
  37
  38 static 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
  44 static 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
  50 static u8 ns16550_tstc(void)
  51 {
  52         return ((in_8(reg_base + (UART_LSR << reg_shift)) & UART_LSR_DR) != 0);
  53 }
  54
  55 int 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 }