arch/mips/sibyte/swarm/dbg_io.c

   1 /*
   2  * kgdb debug routines for SiByte boards.
   3  *
   4  * Copyright (C) 2001 MontaVista Software Inc.
   5  * Author: Jun Sun, 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 /* -------------------- BEGINNING OF CONFIG --------------------- */
  15
  16 #include <linux/delay.h>
  17 #include <asm/io.h>
  18 #include <asm/sibyte/sb1250.h>
  19 #include <asm/sibyte/sb1250_regs.h>
  20 #include <asm/sibyte/sb1250_uart.h>
  21 #include <asm/sibyte/sb1250_int.h>
  22 #include <asm/addrspace.h>
  23
  24 /*
  25  * We use the second serial port for kgdb traffic.
  26  *      115200, 8, N, 1.
  27  */
  28
  29 #define BAUD_RATE               115200
  30 #define CLK_DIVISOR             V_DUART_BAUD_RATE(BAUD_RATE)
  31 #define DATA_BITS               V_DUART_BITS_PER_CHAR_8         /* or 7    */
  32 #define PARITY                  V_DUART_PARITY_MODE_NONE        /* or even */
  33 #define STOP_BITS               M_DUART_STOP_BIT_LEN_1          /* or 2    */
  34
  35 static int duart_initialized = 0;       /* 0: need to be init'ed by kgdb */
  36
  37 /* -------------------- END OF CONFIG --------------------- */
  38 extern int kgdb_port;
  39
  40 #define duart_out(reg, val)     csr_out32(val, IOADDR(A_DUART_CHANREG(kgdb_port, reg)))
  41 #define duart_in(reg)           csr_in32(IOADDR(A_DUART_CHANREG(kgdb_port, reg)))
  42
  43 void putDebugChar(unsigned char c);
  44 unsigned char getDebugChar(void);
  45 static void
  46 duart_init(int clk_divisor, int data, int parity, int stop)
  47 {
  48         duart_out(R_DUART_MODE_REG_1, data | parity);
  49         duart_out(R_DUART_MODE_REG_2, stop);
  50         duart_out(R_DUART_CLK_SEL, clk_divisor);
  51
  52         duart_out(R_DUART_CMD, M_DUART_RX_EN | M_DUART_TX_EN);  /* enable rx and tx */
  53 }
  54
  55 void
  56 putDebugChar(unsigned char c)
  57 {
  58         if (!duart_initialized) {
  59                 duart_initialized = 1;
  60                 duart_init(CLK_DIVISOR, DATA_BITS, PARITY, STOP_BITS);
  61         }
  62         while ((duart_in(R_DUART_STATUS) & M_DUART_TX_RDY) == 0);
  63         duart_out(R_DUART_TX_HOLD, c);
  64 }
  65
  66 unsigned char
  67 getDebugChar(void)
  68 {
  69         if (!duart_initialized) {
  70                 duart_initialized = 1;
  71                 duart_init(CLK_DIVISOR, DATA_BITS, PARITY, STOP_BITS);
  72         }
  73         while ((duart_in(R_DUART_STATUS) & M_DUART_RX_RDY) == 0) ;
  74         return duart_in(R_DUART_RX_HOLD);
  75 }
  76