memory.c

GDB Remote Stub Backend for debugging an embedded ARM system via JTAG common hardware debug interfac

/*
 *  Copyright (C) 2004 Tobias Lorenz
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

/* memory functions */

#include <stdio.h>
#include <stdlib.h>

#include "debug.h"
#include "jtag.h"

/* memory cache variables */
unsigned long memory_cache_valid = 0;
unsigned long memory_cache_address;
unsigned long memory_cache_data;

void memory_preload()
{
    debug_exec_begin();
    debug_exec(0xe1a00000, 0, DEBUG_SPEED);	/* NOP */

    /* Run at system speed */
    debug_exec(0xe1a00000, 0, SYSTEM_SPEED);
    jtag_instruction(JTAG_RESTART, NULL, 0);
    debug_exec_begin();

    debug_exec(0xe1a00000, 0, DEBUG_SPEED);	/* NOP */
    debug_exec(0xe1a00000, 0, DEBUG_SPEED);	/* NOP */
}

void memory_address_check(unsigned long address)
{
    if (address % 4 != 0) {
	printf("WARNING: Address % 4 != 0\n");
	exit(1);
    }
}

void memory_peek(unsigned long address, unsigned long *data)
{
    unsigned long alignment = address % 4;
    
    /* Reading from a not 32-bit aligned address */
    if (alignment) {
	unsigned long address32 = address & ~(0x03);
	unsigned long data0;
	unsigned long data4;
	
	memory_peek(address32+0, &data0);
	memory_peek(address32+4, &data4);
	printf("memory_peek: Alignment %i\n", address%4);
	switch (alignment) {
	    case 1:	*data = ((data0 & 0x00ffffff) <<  8) | ((data4 & 0xff000000) >> 24); break;
	    case 2:	*data = ((data0 & 0x0000ffff) << 16) | ((data4 & 0xffff0000) >> 16); break;
	    case 3:	*data = ((data0 & 0x000000ff) << 24) | ((data4 & 0xffffff00) >>  8); break;
	    default:	printf("memory_peek: Alignment error\n");
	}
	
	return;
    }

    /* Check cache for valid data */
    if (memory_cache_valid && (memory_cache_address == address)) {
	printf("*");
	*data = memory_cache_data;
	return;
    }

    /* Do the read */
    // memory_address_check(address);
    debug_exec_begin();
    debug_exec(0xe5900000, 0      , DEBUG_SPEED);	/* LDR r0, [r0]		- put address in r0 */
    debug_exec(0xe1a00000, 0      , DEBUG_SPEED);	/* NOP */
    debug_exec(0xe1a00000, 0      , DEBUG_SPEED);	/* NOP */
    debug_exec(0xe1a00000, address, DEBUG_SPEED);	/* NOP 			- scan in address */
    debug_exec(0xe4901000, 0      , DEBUG_SPEED);	/* LDR r1, [r0]		- load r1 from location of r0 */

    /* Run at system speed */
    debug_exec(0xe1a00000, 0      , SYSTEM_SPEED);
    jtag_instruction(JTAG_RESTART, NULL, 0);
    debug_exec_begin();

    debug_exec(0xe4801000, 0      , DEBUG_SPEED);	/* STR r1, [r0]		- output the data value */
    debug_exec(0xe1a00000, 0      , DEBUG_SPEED);	/* NOP */
    debug_exec(0xe1a00000, 0      , DEBUG_SPEED);	/* NOP */
    *data =
    debug_exec(0xe1a00000, 0      , DEBUG_SPEED);	/* NOP */

    /* Cache last value */
    memory_cache_valid   = 1;
    memory_cache_address = address;
    memory_cache_data    = *data;
}

void memory_poke(unsigned long address, unsigned long data)
{
    unsigned long alignment = address % 4;

    /* Writing from a not 32-bit aligned address */
    if (alignment) {
	unsigned long address32 = address & ~(0x03);
	unsigned long data0;
	unsigned long data4;
	
	memory_peek(address32+0, &data0);
	memory_peek(address32+4, &data4);
	printf("memory_poke: Alignment %i\n", address%4);
	switch (alignment) {
	    case 1:	data0 &= 0xff000000;
			data4 &= 0x00ffffff;
			data0 |= (data & 0xffffff00) >>  8;
			data4 |= (data & 0x000000ff) << 24;
			break;
	    case 2:	data0 &= 0xffff0000;
			data4 &= 0x0000ffff;
			data0 |= (data & 0xffff0000) >> 16;
			data4 |= (data & 0x0000ffff) << 16;
			break;
	    case 3:	data0 &= 0xffffff00;
			data4 &= 0x000000ff;
			data0 |= (data & 0xff000000) >> 24;
			data4 |= (data & 0x00ffffff) <<  8;
			break;
	    default:	printf("memory_poke: Alignment error\n");
	}
	memory_poke(address32+0, data0);
	memory_poke(address32+4, data4);
	
	return;
    }

    memory_address_check(address);
    debug_exec_begin();
    debug_exec(0xe8900003, 0      , DEBUG_SPEED);	/* LDMIA r0, [r0, r1]	- put address and data */
    debug_exec(0xe1a00000, 0      , DEBUG_SPEED);	/* NOP */
    debug_exec(0xe1a00000, 0      , DEBUG_SPEED);	/* NOP */
    debug_exec(0xe1a00000, address, DEBUG_SPEED);	/* NOP 			- scan in address */
    debug_exec(0xe1a00000, data   , DEBUG_SPEED);	/* NOP 			- scan in data */

    debug_exec(0xe4801000, 0, DEBUG_SPEED);		/* STR r1, [r0]		- store r1 in location of r0 */

    /* Run at system speed */
    debug_exec(0xe1a00000, 0, SYSTEM_SPEED);
    jtag_instruction(JTAG_RESTART, NULL, 0);
    //do {
    //    usleep(100);
    //} while (!ice_halted());

    /* Cache last value */
    memory_cache_valid   = 1;
    memory_cache_address = address;
    memory_cache_data    = data;
}

void memory_read(unsigned long address, unsigned long *data, unsigned long length)
{
    unsigned long temp;

    memory_cache_valid = 0;
    memory_preload();
    while (length-- > 0) {
	memory_peek(address, data);
	
	/* increase the pointers */
	address += 4;
	data    ++;
    }
}

void memory_write(unsigned long address, unsigned long *data, unsigned long length)
{
    unsigned long temp;

    memory_cache_valid = 0;
    memory_preload();
    while (length-- > 0) {
	memory_poke(address, *data);
	
	/* increase the pointers */
	address += 4;
	data    ++;
    }
}