target/linux/generic-2.6/image/lzma-loader/src/uart16550.c

   1 /*
   2  * Copyright (C) 2001 MontaVista Software Inc.
   3  * Author: Jun Sun, jsun@mvista.com or jsun@junsun.net
   4  *
   5  * This program is free software; you can redistribute  it and/or modify it
   6  * under  the terms of  the GNU General  Public License as published by the
   7  * Free Software Foundation;  either version 2 of the  License, or (at your
   8  * option) any later version.
   9  *
  10  */
  11
  12
  13 #include "uart16550.h"
  14
  15 /* === CONFIG === */
  16
  17 #define         BASE                    0xb8058000
  18 #define         MAX_BAUD                1152000
  19 #define         REG_OFFSET              4
  20
  21 /* === END OF CONFIG === */
  22
  23 /* register offset */
  24 #define         OFS_RCV_BUFFER          (0*REG_OFFSET)
  25 #define         OFS_TRANS_HOLD          (0*REG_OFFSET)
  26 #define         OFS_SEND_BUFFER         (0*REG_OFFSET)
  27 #define         OFS_INTR_ENABLE         (1*REG_OFFSET)
  28 #define         OFS_INTR_ID             (2*REG_OFFSET)
  29 #define         OFS_DATA_FORMAT         (3*REG_OFFSET)
  30 #define         OFS_LINE_CONTROL        (3*REG_OFFSET)
  31 #define         OFS_MODEM_CONTROL       (4*REG_OFFSET)
  32 #define         OFS_RS232_OUTPUT        (4*REG_OFFSET)
  33 #define         OFS_LINE_STATUS         (5*REG_OFFSET)
  34 #define         OFS_MODEM_STATUS        (6*REG_OFFSET)
  35 #define         OFS_RS232_INPUT         (6*REG_OFFSET)
  36 #define         OFS_SCRATCH_PAD         (7*REG_OFFSET)
  37
  38 #define         OFS_DIVISOR_LSB         (0*REG_OFFSET)
  39 #define         OFS_DIVISOR_MSB         (1*REG_OFFSET)
  40
  41
  42 /* memory-mapped read/write of the port */
  43 #define         UART16550_READ(y)    (*((volatile uint32*)(BASE + y)))
  44 #define         UART16550_WRITE(y, z)  ((*((volatile uint32*)(BASE + y))) = z)
  45
  46 #define DEBUG_LED (*(unsigned short*)0xb7ffffc0)
  47 #define OutputLED(x)  (DEBUG_LED = x)
  48
  49 void Uart16550Init(uint32 baud, uint8 data, uint8 parity, uint8 stop)
  50 {
  51     /* disable interrupts */
  52     UART16550_WRITE(OFS_INTR_ENABLE, 0);
  53
  54     /* set up buad rate */
  55     {
  56         uint32 divisor;
  57
  58         /* set DIAB bit */
  59         UART16550_WRITE(OFS_LINE_CONTROL, 0x80);
  60
  61         /* set divisor */
  62         divisor = MAX_BAUD / baud;
  63         UART16550_WRITE(OFS_DIVISOR_LSB, divisor & 0xff);
  64         UART16550_WRITE(OFS_DIVISOR_MSB, (divisor & 0xff00)>>8);
  65
  66         /* clear DIAB bit */
  67         UART16550_WRITE(OFS_LINE_CONTROL, 0x0);
  68     }
  69
  70     /* set data format */
  71     UART16550_WRITE(OFS_DATA_FORMAT, data | parity | stop);
  72 }
  73
  74 uint8 Uart16550GetPoll()
  75 {
  76     while((UART16550_READ(OFS_LINE_STATUS) & 0x1) == 0);
  77     return UART16550_READ(OFS_RCV_BUFFER);
  78 }
  79
  80
  81 void Uart16550Put(uint8 byte)
  82 {
  83     while ((UART16550_READ(OFS_LINE_STATUS) &0x20) == 0);
  84     UART16550_WRITE(OFS_SEND_BUFFER, byte);
  85 }
  86