target.c

/***************************************************************************
 *   Copyright (C) 2005 by Dominic Rath                                    *
 *   Dominic.Rath@gmx.de                                                   *
 *                                                                         *
 *   Copyright (C) 2007,2008 yvind Harboe                                      *
 *   oyvind.harboe@zylin.com                                               *
 *                                                                         *
 *   This program is free software; you can redistribute it and/or modify  *
 *   it under the terms of the GNU General Public License as published by  *
 *   the Free Software Foundation; either version 2 of the License, or     *
 *   (at your option) any later version.                                   *
 *                                                                         *
 *   This program is distributed in the hope that it will be useful,       *
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
 *   GNU General Public License for more details.                          *
 *                                                                         *
 *   You should have received a copy of the GNU General Public License     *
 *   along with this program; if not, write to the                         *
 *   Free Software Foundation, Inc.,                                       *
 *   59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.             *
 ***************************************************************************/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include "replacements.h"
#include "target.h"
#include "target_request.h"

#include "log.h"
#include "configuration.h"
#include "binarybuffer.h"
#include "jtag.h"

#include <string.h>
#include <stdlib.h>
#include <inttypes.h>

#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <errno.h>

#include <sys/time.h>
#include <time.h>

#include <time_support.h>

#include <fileio.h>
#include <image.h>

int cli_target_callback_event_handler(struct target_s *target, enum target_event event, void *priv);

int handle_target_command(struct command_context_s *cmd_ctx, char *cmd, char **args, int argc);
int handle_targets_command(struct command_context_s *cmd_ctx, char *cmd, char **args, int argc);

int handle_working_area_command(struct command_context_s *cmd_ctx, char *cmd, char **args, int argc);

int handle_reg_command(struct command_context_s *cmd_ctx, char *cmd, char **args, int argc);
int handle_poll_command(struct command_context_s *cmd_ctx, char *cmd, char **args, int argc);
int handle_halt_command(struct command_context_s *cmd_ctx, char *cmd, char **args, int argc);
int handle_wait_halt_command(struct command_context_s *cmd_ctx, char *cmd, char **args, int argc);
int handle_reset_command(struct command_context_s *cmd_ctx, char *cmd, char **args, int argc);
int handle_soft_reset_halt_command(struct command_context_s *cmd_ctx, char *cmd, char **args, int argc);
int handle_resume_command(struct command_context_s *cmd_ctx, char *cmd, char **args, int argc);
int handle_step_command(struct command_context_s *cmd_ctx, char *cmd, char **args, int argc);
int handle_md_command(struct command_context_s *cmd_ctx, char *cmd, char **args, int argc);
int handle_mw_command(struct command_context_s *cmd_ctx, char *cmd, char **args, int argc);
int handle_load_image_command(struct command_context_s *cmd_ctx, char *cmd, char **args, int argc);
int handle_dump_image_command(struct command_context_s *cmd_ctx, char *cmd, char **args, int argc);
int handle_verify_image_command(struct command_context_s *cmd_ctx, char *cmd, char **args, int argc);
int handle_bp_command(struct command_context_s *cmd_ctx, char *cmd, char **args, int argc);
int handle_rbp_command(struct command_context_s *cmd_ctx, char *cmd, char **args, int argc);
int handle_wp_command(struct command_context_s *cmd_ctx, char *cmd, char **args, int argc);
int handle_rwp_command(struct command_context_s *cmd_ctx, char *cmd, char **args, int argc);
int handle_virt2phys_command(command_context_t *cmd_ctx, char *cmd, char **args, int argc);
int handle_profile_command(struct command_context_s *cmd_ctx, char *cmd, char **args, int argc);
static int jim_array2mem(Jim_Interp *interp, int argc, Jim_Obj *const *argv);
static int jim_mem2array(Jim_Interp *interp, int argc, Jim_Obj *const *argv);


/* targets */
extern target_type_t arm7tdmi_target;
extern target_type_t arm720t_target;
extern target_type_t arm9tdmi_target;
extern target_type_t arm920t_target;
extern target_type_t arm966e_target;
extern target_type_t arm926ejs_target;
extern target_type_t feroceon_target;
extern target_type_t xscale_target;
extern target_type_t cortexm3_target;
extern target_type_t arm11_target;
extern target_type_t mips_m4k_target;

target_type_t *target_types[] =
{
	&arm7tdmi_target,
	&arm9tdmi_target,
	&arm920t_target,
	&arm720t_target,
	&arm966e_target,
	&arm926ejs_target,
	&feroceon_target,
	&xscale_target,
	&cortexm3_target,
	&arm11_target,
	&mips_m4k_target,
	NULL,
};

target_t *targets = NULL;
target_event_callback_t *target_event_callbacks = NULL;
target_timer_callback_t *target_timer_callbacks = NULL;

char *target_state_strings[] =
{
	"unknown",
	"running",
	"halted",
	"reset",
	"debug_running",
};

char *target_debug_reason_strings[] =
{
	"debug request", "breakpoint", "watchpoint",
	"watchpoint and breakpoint", "single step",
	"target not halted", "undefined"
};

char *target_endianess_strings[] =
{
	"big endian",
	"little endian",
};

static int target_continous_poll = 1;

/* read a u32 from a buffer in target memory endianness */
u32 target_buffer_get_u32(target_t *target, u8 *buffer)
{
	if (target->endianness == TARGET_LITTLE_ENDIAN)
		return le_to_h_u32(buffer);
	else
		return be_to_h_u32(buffer);
}

/* read a u16 from a buffer in target memory endianness */
u16 target_buffer_get_u16(target_t *target, u8 *buffer)
{
	if (target->endianness == TARGET_LITTLE_ENDIAN)
		return le_to_h_u16(buffer);
	else
		return be_to_h_u16(buffer);
}

/* write a u32 to a buffer in target memory endianness */
void target_buffer_set_u32(target_t *target, u8 *buffer, u32 value)
{
	if (target->endianness == TARGET_LITTLE_ENDIAN)
		h_u32_to_le(buffer, value);
	else
		h_u32_to_be(buffer, value);
}

/* write a u16 to a buffer in target memory endianness */
void target_buffer_set_u16(target_t *target, u8 *buffer, u16 value)
{
	if (target->endianness == TARGET_LITTLE_ENDIAN)
		h_u16_to_le(buffer, value);
	else
		h_u16_to_be(buffer, value);
}

/* returns a pointer to the n-th configured target */
target_t* get_target_by_num(int num)
{
	target_t *target = targets;
	int i = 0;

	while (target)
	{
		if (num == i)
			return target;
		target = target->next;
		i++;
	}

	return NULL;
}

int get_num_by_target(target_t *query_target)
{
	target_t *target = targets;
	int i = 0;

	while (target)
	{
		if (target == query_target)
			return i;
		target = target->next;
		i++;
	}

	return -1;
}

target_t* get_current_target(command_context_t *cmd_ctx)
{
	target_t *target = get_target_by_num(cmd_ctx->current_target);

	if (target == NULL)
	{
		LOG_ERROR("BUG: current_target out of bounds");
		exit(-1);
	}

	return target;
}


int target_poll(struct target_s *target)
{
	/* We can't poll until after examine */
	if (!target->type->examined)
	{
		/* Fail silently lest we pollute the log */
		return ERROR_FAIL;
	}
	return target->type->poll(target);
}

int target_halt(struct target_s *target)
{
	/* We can't poll until after examine */
	if (!target->type->examined)
	{
		LOG_ERROR("Target not examined yet");
		return ERROR_FAIL;
	}
	return target->type->halt(target);
}

int target_resume(struct target_s *target, int current, u32 address, int handle_breakpoints, int debug_execution)
{
	int retval;

	/* We can't poll until after examine */
	if (!target->type->examined)
	{
		LOG_ERROR("Target not examined yet");
		return ERROR_FAIL;
	}

	/* note that resume *must* be asynchronous. The CPU can halt before we poll. The CPU can
	 * even halt at the current PC as a result of a software breakpoint being inserted by (a bug?)
	 * the application.
	 */
	if ((retval = target->type->resume(target, current, address, handle_breakpoints, debug_execution)) != ERROR_OK)
		return retval;

	return retval;
}

int target_process_reset(struct command_context_s *cmd_ctx, enum target_reset_mode reset_mode)
{
	int retval = ERROR_OK;
	target_t *target;

	target = targets;
	while (target)
	{
		target_invoke_script(cmd_ctx, target, "pre_reset");
		target = target->next;
	}

	if ((retval = jtag_init_reset(cmd_ctx)) != ERROR_OK)
		return retval;

	keep_alive(); /* we might be running on a very slow JTAG clk */

	/* First time this is executed after launching OpenOCD, it will read out
	 * the type of CPU, etc. and init Embedded ICE registers in host
	 * memory.
	 *
	 * It will also set up ICE registers in the target.
	 *
	 * However, if we assert TRST later, we need to set up the registers again.
	 *
	 * For the "reset halt/init" case we must only set up the registers here.
	 */
	if ((retval = target_examine()) != ERROR_OK)
		return retval;

	keep_alive(); /* we might be running on a very slow JTAG clk */

	target = targets;
	while (target)
	{
		/* we have no idea what state the target is in, so we
		 * have to drop working areas
		 */
		target_free_all_working_areas_restore(target, 0);
		target->reset_halt=((reset_mode==RESET_HALT)||(reset_mode==RESET_INIT));
		if ((retval = target->type->assert_reset(target))!=ERROR_OK)
			return retval;
		target = target->next;
	}

	/* request target halt if necessary, and schedule further action */
	target = targets;
	while (target)
	{
		if (reset_mode!=RESET_RUN)
		{
			if ((retval = target_halt(target))!=ERROR_OK)
				return retval;
		}
		target = target->next;
	}

	target = targets;
	while (target)
	{
		if ((retval = target->type->deassert_reset(target))!=ERROR_OK)
			return retval;
		target = target->next;
	}

	target = targets;
	while (target)
	{
		/* We can fail to bring the target into the halted state, try after reset has been deasserted  */
		if (target->reset_halt)
		{
			/* wait up to 1 second for halt. */
			target_wait_state(target, TARGET_HALTED, 1000);
			if (target->state != TARGET_HALTED)
			{
				LOG_WARNING("Failed to reset target into halted mode - issuing halt");
				if ((retval = target->type->halt(target))!=ERROR_OK)
					return retval;
			}
		}

		target = target->next;
	}


	LOG_DEBUG("Waiting for halted stated as appropriate");

	if ((reset_mode == RESET_HALT) || (reset_mode == RESET_INIT))
	{
		target = targets;
		while (target)
		{
			/* Wait for reset to complete, maximum 5 seconds. */
			if (((retval=target_wait_state(target, TARGET_HALTED, 5000)))==ERROR_OK)
			{
				if (reset_mode == RESET_INIT)
					target_invoke_script(cmd_ctx, target, "post_reset");
			}
			target = target->next;
		}
	}

	/* We want any events to be processed before the prompt */
	target_call_timer_callbacks_now();

	return retval;
}

static int default_virt2phys(struct target_s *target, u32 virtual, u32 *physical)
{
	*physical = virtual;
	return ERROR_OK;
}

static int default_mmu(struct target_s *target, int *enabled)
{
	*enabled = 0;
	return ERROR_OK;
}

static int default_examine(struct target_s *target)
{
	target->type->examined = 1;
	return ERROR_OK;
}


/* Targets that correctly implement init+examine, i.e.
 * no communication with target during init:
 *
 * XScale
 */
int target_examine(struct command_context_s *cmd_ctx)
{
	int retval = ERROR_OK;
	target_t *target = targets;
	while (target)
	{
		if ((retval = target->type->examine(target))!=ERROR_OK)
			return retval;
		target = target->next;
	}
	return retval;
}

static int target_write_memory_imp(struct target_s *target, u32 address, u32 size, u32 count, u8 *buffer)
{
	if (!target->type->examined)
	{
		LOG_ERROR("Target not examined yet");
		return ERROR_FAIL;
	}
	return target->type->write_memory_imp(target, address, size, count, buffer);
}

static int target_read_memory_imp(struct target_s *target, u32 address, u32 size, u32 count, u8 *buffer)
{
	if (!target->type->examined)
	{
		LOG_ERROR("Target not examined yet");
		return ERROR_FAIL;
	}
	return target->type->read_memory_imp(target, address, size, count, buffer);
}

static int target_soft_reset_halt_imp(struct target_s *target)
{
	if (!target->type->examined)
	{
		LOG_ERROR("Target not examined yet");
		return ERROR_FAIL;
	}
	return target->type->soft_reset_halt_imp(target);
}

static int target_run_algorithm_imp(struct target_s *target, int num_mem_params, mem_param_t *mem_params, int num_reg_params, reg_param_t *reg_param, u32 entry_point, u32 exit_point, int timeout_ms, void *arch_info)
{
	if (!target->type->examined)
	{
		LOG_ERROR("Target not examined yet");
		return ERROR_FAIL;
	}
	return target->type->run_algorithm_imp(target, num_mem_params, mem_params, num_reg_params, reg_param, entry_point, exit_point, timeout_ms, arch_info);
}

int target_init(struct command_context_s *cmd_ctx)
{
	target_t *target = targets;

	while (target)
	{
		target->type->examined = 0;
		if (target->type->examine == NULL)
		{
			target->type->examine = default_examine;
		}

		if (target->type->init_target(cmd_ctx, target) != ERROR_OK)
		{
			LOG_ERROR("target '%s' init failed", target->type->name);
			exit(-1);
		}

		/* Set up default functions if none are provided by target */
		if (target->type->virt2phys == NULL)
		{
			target->type->virt2phys = default_virt2phys;
		}
		target->type->virt2phys = default_virt2phys;
		/* a non-invasive way(in terms of patches) to add some code that
		 * runs before the type->write/read_memory implementation
		 */
		target->type->write_memory_imp = target->type->write_memory;
		target->type->write_memory = target_write_memory_imp;
		target->type->read_memory_imp = target->type->read_memory;
		target->type->read_memory = target_read_memory_imp;
		target->type->soft_reset_halt_imp = target->type->soft_reset_halt;
		target->type->soft_reset_halt = target_soft_reset_halt_imp;
		target->type->run_algorithm_imp = target->type->run_algorithm;
		target->type->run_algorithm = target_run_algorithm_imp;


		if (target->type->mmu == NULL)
		{
			target->type->mmu = default_mmu;
		}
		target = target->next;
	}

	if (targets)
	{
		target_register_user_commands(cmd_ctx);
		target_register_timer_callback(handle_target, 100, 1, NULL);
	}

	return ERROR_OK;
}

int target_register_event_callback(int (*callback)(struct target_s *target, enum target_event event, void *priv), void *priv)
{
	target_event_callback_t **callbacks_p = &target_event_callbacks;

	if (callback == NULL)
	{
		return ERROR_INVALID_ARGUMENTS;
	}

	if (*callbacks_p)
	{
		while ((*callbacks_p)->next)
			callbacks_p = &((*callbacks_p)->next);
		callbacks_p = &((*callbacks_p)->next);
	}

	(*callbacks_p) = malloc(sizeof(target_event_callback_t));
	(*callbacks_p)->callback = callback;
	(*callbacks_p)->priv = priv;
	(*callbacks_p)->next = NULL;

	return ERROR_OK;
}

int target_register_timer_callback(int (*callback)(void *priv), int time_ms, int periodic, void *priv)
{
	target_timer_callback_t **callbacks_p = &target_timer_callbacks;
	struct timeval now;

	if (callback == NULL)
	{
		return ERROR_INVALID_ARGUMENTS;
	}

	if (*callbacks_p)
	{
		while ((*callbacks_p)->next)
			callbacks_p = &((*callbacks_p)->next);
		callbacks_p = &((*callbacks_p)->next);
	}

	(*callbacks_p) = malloc(sizeof(target_timer_callback_t));
	(*callbacks_p)->callback = callback;
	(*callbacks_p)->periodic = periodic;
	(*callbacks_p)->time_ms = time_ms;

	gettimeofday(&now, NULL);
	(*callbacks_p)->when.tv_usec = now.tv_usec + (time_ms % 1000) * 1000;
	time_ms -= (time_ms % 1000);
	(*callbacks_p)->when.tv_sec = now.tv_sec + (time_ms / 1000);
	if ((*callbacks_p)->when.tv_usec > 1000000)
	{
		(*callbacks_p)->when.tv_usec = (*callbacks_p)->when.tv_usec - 1000000;
		(*callbacks_p)->when.tv_sec += 1;
	}

	(*callbacks_p)->priv = priv;
	(*callbacks_p)->next = NULL;

	return ERROR_OK;
}

int target_unregister_event_callback(int (*callback)(struct target_s *target, enum target_event event, void *priv), void *priv)
{
	target_event_callback_t **p = &target_event_callbacks;
	target_event_callback_t *c = target_event_callbacks;

	if (callback == NULL)
	{
		return ERROR_INVALID_ARGUMENTS;
	}

	while (c)
	{
		target_event_callback_t *next = c->next;
		if ((c->callback == callback) && (c->priv == priv))
		{
			*p = next;
			free(c);
			return ERROR_OK;
		}
		else
			p = &(c->next);
		c = next;
	}

	return ERROR_OK;
}

int target_unregister_timer_callback(int (*callback)(void *priv), void *priv)
{
	target_timer_callback_t **p = &target_timer_callbacks;
	target_timer_callback_t *c = target_timer_callbacks;

	if (callback == NULL)
	{
		return ERROR_INVALID_ARGUMENTS;
	}

	while (c)
	{
		target_timer_callback_t *next = c->next;
		if ((c->callback == callback) && (c->priv == priv))
		{
			*p = next;
			free(c);
			return ERROR_OK;
		}
		else
			p = &(c->next);
		c = next;
	}

	return ERROR_OK;
}

int target_call_event_callbacks(target_t *target, enum target_event event)
{
	target_event_callback_t *callback = target_event_callbacks;
	target_event_callback_t *next_callback;

	LOG_DEBUG("target event %i", event);

	while (callback)
	{
		next_callback = callback->next;
		callback->callback(target, event, callback->priv);
		callback = next_callback;
	}

	return ERROR_OK;
}

static int target_call_timer_callbacks_check_time(int checktime)
{
	target_timer_callback_t *callback = target_timer_callbacks;
	target_timer_callback_t *next_callback;
	struct timeval now;

	keep_alive();

	gettimeofday(&now, NULL);

	while (callback)
	{
		next_callback = callback->next;

		if ((!checktime&&callback->periodic)||
				(((now.tv_sec >= callback->when.tv_sec) && (now.tv_usec >= callback->when.tv_usec))
						|| (now.tv_sec > callback->when.tv_sec)))
		{
			if(callback->callback != NULL)
			{
				callback->callback(callback->priv);
				if (callback->periodic)
				{
					int time_ms = callback->time_ms;
					callback->when.tv_usec = now.tv_usec + (time_ms % 1000) * 1000;
					time_ms -= (time_ms % 1000);
					callback->when.tv_sec = now.tv_sec + time_ms / 1000;
					if (callback->when.tv_usec > 1000000)
					{
						callback->when.tv_usec = callback->when.tv_usec - 1000000;
						callback->when.tv_sec += 1;
					}
				}
				else
					target_unregister_timer_callback(callback->callback, callback->priv);
			}
		}

		callback = next_callback;
	}

	return ERROR_OK;
}

int target_call_timer_callbacks()
{
	return target_call_timer_callbacks_check_time(1);
}

/* invoke periodic callbacks immediately */
int target_call_timer_callbacks_now()
{
	return target_call_timer_callbacks(0);
}

int target_alloc_working_area(struct target_s *target, u32 size, working_area_t **area)
{
	working_area_t *c = target->working_areas;
	working_area_t *new_wa = NULL;

	/* Reevaluate working area address based on MMU state*/
	if (target->working_areas == NULL)
	{
		int retval;
		int enabled;
		retval = target->type->mmu(target, &enabled);
		if (retval != ERROR_OK)
		{
			return retval;
		}
		if (enabled)
		{
			target->working_area = target->working_area_virt;
		}
		else
		{
			target->working_area = target->working_area_phys;
		}
	}

	/* only allocate multiples of 4 byte */
	if (size % 4)
	{
		LOG_ERROR("BUG: code tried to allocate unaligned number of bytes, padding");
		size = CEIL(size, 4);
	}

	/* see if there's already a matching working area */
	while (c)
	{
		if ((c->free) && (c->size == size))
		{
			new_wa = c;
			break;
		}
		c = c->next;
	}

	/* if not, allocate a new one */
	if (!new_wa)
	{
		working_area_t **p = &target->working_areas;
		u32 first_free = target->working_area;
		u32 free_size = target->working_area_size;

		LOG_DEBUG("allocating new working area");

		c = target->working_areas;
		while (c)
		{
			first_free += c->size;
			free_size -= c->size;
			p = &c->next;
			c = c->next;
		}

		if (free_size < size)
		{
			LOG_WARNING("not enough working area available(requested %d, free %d)", size, free_size);
			return ERROR_TARGET_RESOURCE_NOT_AVAILABLE;
		}

		new_wa = malloc(sizeof(working_area_t));
		new_wa->next = NULL;
		new_wa->size = size;
		new_wa->address = first_free;

		if (target->backup_working_area)
		{
			new_wa->backup = malloc(new_wa->size);
			target->type->read_memory(target, new_wa->address, 4, new_wa->size / 4, new_wa->backup);
		}
		else
		{
			new_wa->backup = NULL;
		}

		/* put new entry in list */
		*p = new_wa;
	}

	/* mark as used, and return the new (reused) area */
	new_wa->free = 0;
	*area = new_wa;

	/* user pointer */
	new_wa->user = area;

	return ERROR_OK;
}

int target_free_working_area_restore(struct target_s *target, working_area_t *area, int restore)
{
	if (area->free)
		return ERROR_OK;

	if (restore&&target->backup_working_area)
		target->type->write_memory(target, area->address, 4, area->size / 4, area->backup);

	area->free = 1;

	/* mark user pointer invalid */
	*area->user = NULL;
	area->user = NULL;

	return ERROR_OK;
}

int target_free_working_area(struct target_s *target, working_area_t *area)
{
	return target_free_working_area_restore(target, area, 1);
}

int target_free_all_working_areas_restore(struct target_s *target, int restore)
{
	working_area_t *c = target->working_areas;

	while (c)
	{
		working_area_t *next = c->next;
		target_free_working_area_restore(target, c, restore);

		if (c->backup)
			free(c->backup);

		free(c);

		c = next;
	}

	target->working_areas = NULL;

	return ERROR_OK;
}

int target_free_all_working_areas(struct target_s *target)
{
	return target_free_all_working_areas_restore(target, 1);
}

int target_register_commands(struct command_context_s *cmd_ctx)
{
	register_command(cmd_ctx, NULL, "target", handle_target_command, COMMAND_CONFIG, "target <cpu> [reset_init default - DEPRECATED] <chainpos> <endianness> <variant> [cpu type specifc args]");
	register_command(cmd_ctx, NULL, "targets", handle_targets_command, COMMAND_EXEC, NULL);
	register_command(cmd_ctx, NULL, "working_area", handle_working_area_command, COMMAND_ANY, "working_area <target#> <address> <size> <'backup'|'nobackup'> [virtual address]");
	register_command(cmd_ctx, NULL, "virt2phys", handle_virt2phys_command, COMMAND_ANY, "virt2phys <virtual address>");
	register_command(cmd_ctx, NULL, "profile", handle_profile_command, COMMAND_EXEC, "PRELIMINARY! - profile <seconds> <gmon.out>");


	/* script procedures */
	register_jim(cmd_ctx, "ocd_mem2array", jim_mem2array, "read memory and return as a TCL array for script processing");
	register_jim(cmd_ctx, "ocd_array2mem", jim_array2mem, "convert a TCL array to memory locations and write the values");
	return ERROR_OK;
}

int target_arch_state(struct target_s *target)
{
	int retval;
	if (target==NULL)
	{
		LOG_USER("No target has been configured");
		return ERROR_OK;
	}

	LOG_USER("target state: %s", target_state_strings[target->state]);

	if (target->state!=TARGET_HALTED)
		return ERROR_OK;

	retval=target->type->arch_state(target);
	return retval;
}

/* Single aligned words are guaranteed to use 16 or 32 bit access
 * mode respectively, otherwise data is handled as quickly as
 * possible
 */
int target_write_buffer(struct target_s *target, u32 address, u32 size, u8 *buffer)
{
	int retval;
	LOG_DEBUG("writing buffer of %i byte at 0x%8.8x", size, address);

	if (!target->type->examined)
	{
		LOG_ERROR("Target not examined yet");
		return ERROR_FAIL;
	}

	if (address+size<address)
	{
		/* GDB can request this when e.g. PC is 0xfffffffc*/
		LOG_ERROR("address+size wrapped(0x%08x, 0x%08x)", address, size);
		return ERROR_FAIL;
	}

	if (((address % 2) == 0) && (size == 2))
	{
		return target->type->write_memory(target, address, 2, 1, buffer);
	}

	/* handle unaligned head bytes */
	if (address % 4)
	{
		int unaligned = 4 - (address % 4);

		if (unaligned > size)
			unaligned = size;

		if ((retval = target->type->write_memory(target, address, 1, unaligned, buffer)) != ERROR_OK)
			return retval;

		buffer += unaligned;
		address += unaligned;
		size -= unaligned;
	}

	/* handle aligned words */
	if (size >= 4)
	{
		int aligned = size - (size % 4);

		/* use bulk writes above a certain limit. This may have to be changed */
		if (aligned > 128)
		{
			if ((retval = target->type->bulk_write_memory(target, address, aligned / 4, buffer)) != ERROR_OK)
				return retval;
		}
		else
		{
			if ((retval = target->type->write_memory(target, address, 4, aligned / 4, buffer)) != ERROR_OK)
				return retval;
		}

		buffer += aligned;
		address += aligned;
		size -= aligned;
	}

	/* handle tail writes of less than 4 bytes */
	if (size > 0)
	{
		if ((retval = target->type->write_memory(target, address, 1, size, buffer)) != ERROR_OK)
			return retval;
	}

	return ERROR_OK;
}


/* Single aligned words are guaranteed to use 16 or 32 bit access
 * mode respectively, otherwise data is handled as quickly as
 * possible
 */
int target_read_buffer(struct target_s *target, u32 address, u32 size, u8 *buffer)
{
	int retval;
	LOG_DEBUG("reading buffer of %i byte at 0x%8.8x", size, address);

	if (!target->type->examined)
	{
		LOG_ERROR("Target not examined yet");
		return ERROR_FAIL;
	}

	if (address+size<address)
	{
		/* GDB can request this when e.g. PC is 0xfffffffc*/
		LOG_ERROR("address+size wrapped(0x%08x, 0x%08x)", address, size);
		return ERROR_FAIL;
	}

	if (((address % 2) == 0) && (size == 2))
	{
		return target->type->read_memory(target, address, 2, 1, buffer);
	}

	/* handle unaligned head bytes */
	if (address % 4)
	{
		int unaligned = 4 - (address % 4);

		if (unaligned > size)
			unaligned = size;

		if ((retval = target->type->read_memory(target, address, 1, unaligned, buffer)) != ERROR_OK)
			return retval;

		buffer += unaligned;
		address += unaligned;
		size -= unaligned;
	}

	/* handle aligned words */
	if (size >= 4)
	{
		int aligned = size - (size % 4);

		if ((retval = target->type->read_memory(target, address, 4, aligned / 4, buffer)) != ERROR_OK)
			return retval;

		buffer += aligned;
		address += aligned;
		size -= aligned;
	}