arch/mips/ddb5xxx/ddb5476/dbg_io.c

   1 /*
   2  * kgdb io functions for DDB5476.  We use the second serial port.
   3  *
   4  * Copyright (C) 2001 MontaVista Software Inc.
   5  * Author: jsun@mvista.com or jsun@junsun.net
   6  *
   7  * This program is free software; you can redistribute  it and/or modify it
   8  * under  the terms of  the GNU General  Public License as published by the
   9  * Free Software Foundation;  either version 2 of the  License, or (at your
  10  * option) any later version.
  11  *
  12  */
  13
  14 /* ======================= CONFIG ======================== */
  15
  16 /* [jsun] we use the second serial port for kdb */
  17 #define         BASE                    0xa60002f8
  18 #define         MAX_BAUD                115200
  19
  20 /* distance in bytes between two serial registers */
  21 #define         REG_OFFSET              1
  22
  23 /*
  24  * 0 - kgdb does serial init
  25  * 1 - kgdb skip serial init
  26  */
  27 static int remoteDebugInitialized = 0;
  28
  29 /*
  30  * the default baud rate *if* kgdb does serial init
  31  */
  32 #define         BAUD_DEFAULT            UART16550_BAUD_38400
  33
  34 /* ======================= END OF CONFIG ======================== */
  35
  36 typedef unsigned char uint8;
  37 typedef unsigned int uint32;
  38
  39 #define         UART16550_BAUD_2400             2400
  40 #define         UART16550_BAUD_4800             4800
  41 #define         UART16550_BAUD_9600             9600
  42 #define         UART16550_BAUD_19200            19200
  43 #define         UART16550_BAUD_38400            38400
  44 #define         UART16550_BAUD_57600            57600
  45 #define         UART16550_BAUD_115200           115200
  46
  47 #define         UART16550_PARITY_NONE           0
  48 #define         UART16550_PARITY_ODD            0x08
  49 #define         UART16550_PARITY_EVEN           0x18
  50 #define         UART16550_PARITY_MARK           0x28
  51 #define         UART16550_PARITY_SPACE          0x38
  52
  53 #define         UART16550_DATA_5BIT             0x0
  54 #define         UART16550_DATA_6BIT             0x1
  55 #define         UART16550_DATA_7BIT             0x2
  56 #define         UART16550_DATA_8BIT             0x3
  57
  58 #define         UART16550_STOP_1BIT             0x0
  59 #define         UART16550_STOP_2BIT             0x4
  60
  61 /* register offset */
  62 #define         OFS_RCV_BUFFER          0
  63 #define         OFS_TRANS_HOLD          0
  64 #define         OFS_SEND_BUFFER         0
  65 #define         OFS_INTR_ENABLE         (1*REG_OFFSET)
  66 #define         OFS_INTR_ID             (2*REG_OFFSET)
  67 #define         OFS_DATA_FORMAT         (3*REG_OFFSET)
  68 #define         OFS_LINE_CONTROL        (3*REG_OFFSET)
  69 #define         OFS_MODEM_CONTROL       (4*REG_OFFSET)
  70 #define         OFS_RS232_OUTPUT        (4*REG_OFFSET)
  71 #define         OFS_LINE_STATUS         (5*REG_OFFSET)
  72 #define         OFS_MODEM_STATUS        (6*REG_OFFSET)
  73 #define         OFS_RS232_INPUT         (6*REG_OFFSET)
  74 #define         OFS_SCRATCH_PAD         (7*REG_OFFSET)
  75
  76 #define         OFS_DIVISOR_LSB         (0*REG_OFFSET)
  77 #define         OFS_DIVISOR_MSB         (1*REG_OFFSET)
  78
  79
  80 /* memory-mapped read/write of the port */
  81 #define         UART16550_READ(y)    (*((volatile uint8*)(BASE + y)))
  82 #define         UART16550_WRITE(y, z)  ((*((volatile uint8*)(BASE + y))) = z)
  83
  84 void debugInit(uint32 baud, uint8 data, uint8 parity, uint8 stop)
  85 {
  86         /* disable interrupts */
  87         UART16550_WRITE(OFS_INTR_ENABLE, 0);
  88
  89         /* set up baud rate */
  90         {
  91                 uint32 divisor;
  92
  93                 /* set DIAB bit */
  94                 UART16550_WRITE(OFS_LINE_CONTROL, 0x80);
  95
  96                 /* set divisor */
  97                 divisor = MAX_BAUD / baud;
  98                 UART16550_WRITE(OFS_DIVISOR_LSB, divisor & 0xff);
  99                 UART16550_WRITE(OFS_DIVISOR_MSB, (divisor & 0xff00) >> 8);
 100
 101                 /* clear DIAB bit */
 102                 UART16550_WRITE(OFS_LINE_CONTROL, 0x0);
 103         }
 104
 105         /* set data format */
 106         UART16550_WRITE(OFS_DATA_FORMAT, data | parity | stop);
 107 }
 108
 109
 110 uint8 getDebugChar(void)
 111 {
 112         if (!remoteDebugInitialized) {
 113                 remoteDebugInitialized = 1;
 114                 debugInit(BAUD_DEFAULT,
 115                           UART16550_DATA_8BIT,
 116                           UART16550_PARITY_NONE, UART16550_STOP_1BIT);
 117         }
 118
 119         while ((UART16550_READ(OFS_LINE_STATUS) & 0x1) == 0);
 120         return UART16550_READ(OFS_RCV_BUFFER);
 121 }
 122
 123
 124 int putDebugChar(uint8 byte)
 125 {
 126         if (!remoteDebugInitialized) {
 127                 remoteDebugInitialized = 1;
 128                 debugInit(BAUD_DEFAULT,
 129                           UART16550_DATA_8BIT,
 130                           UART16550_PARITY_NONE, UART16550_STOP_1BIT);
 131         }
 132
 133         while ((UART16550_READ(OFS_LINE_STATUS) & 0x20) == 0);
 134         UART16550_WRITE(OFS_SEND_BUFFER, byte);
 135         return 1;
 136 }