openocd/src/jtag/bitbang.c

/***************************************************************************
 *   Copyright (C) 2005 by Dominic Rath                                    *
 *   Dominic.Rath@gmx.de                                                   *
 *                                                                         *
 *   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 "bitbang.h"

/* project specific includes */
#include "log.h"
#include "types.h"
#include "jtag.h"
#include "configuration.h"

/* system includes */
#include <string.h>
#include <stdlib.h>
#include <unistd.h>

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

bitbang_interface_t *bitbang_interface;

int bitbang_execute_queue(void);

void bitbang_end_state(enum tap_state state)
{
	if (tap_move_map[state] != -1)
		end_state = state;
	else
	{
		ERROR("BUG: %i is not a valid end state", state);
		exit(-1);
	}
}

void bitbang_state_move(void) {
	
	int i=0, tms=0;
	u8 tms_scan = TAP_MOVE(cur_state, end_state);
	
	for (i = 0; i < 7; i++)
	{
		tms = (tms_scan >> i) & 1;
		bitbang_interface->write(0, tms, 0);
		bitbang_interface->write(1, tms, 0);
	}
	bitbang_interface->write(0, tms, 0);
	
	cur_state = end_state;
}

void bitbang_path_move(pathmove_command_t *cmd)
{
	int num_states = cmd->num_states;
	int state_count;

	state_count = 0;
	while (num_states)
	{
		if (tap_transitions[cur_state].low == cmd->path[state_count])
		{
			bitbang_interface->write(0, 0, 0);
			bitbang_interface->write(1, 0, 0);
		}
		else if (tap_transitions[cur_state].high == cmd->path[state_count])
		{
			bitbang_interface->write(0, 1, 0);
			bitbang_interface->write(1, 1, 0);
		}			
		else
		{
			ERROR("BUG: %s -> %s isn't a valid TAP transition", tap_state_strings[cur_state], tap_state_strings[cmd->path[state_count]]);
			exit(-1);
		}
		
		cur_state = cmd->path[state_count];
		state_count++;
		num_states--;
	}
	
	end_state = cur_state;
}

void bitbang_runtest(int num_cycles)
{
	int i;
	
	enum tap_state saved_end_state = end_state;
	
	/* only do a state_move when we're not already in RTI */
	if (cur_state != TAP_RTI)
	{
		bitbang_end_state(TAP_RTI);
		bitbang_state_move();
	}
	
	/* execute num_cycles */
	bitbang_interface->write(0, 0, 0);
	for (i = 0; i < num_cycles; i++)
	{
		bitbang_interface->write(1, 0, 0);
		bitbang_interface->write(0, 0, 0);
	}
	
	/* finish in end_state */
	bitbang_end_state(saved_end_state);
	if (cur_state != end_state)
		bitbang_state_move();
}

void bitbang_scan(int ir_scan, enum scan_type type, u8 *buffer, int scan_size)
{
	enum tap_state saved_end_state = end_state;
	int bit_cnt;
	
	if (ir_scan)
		bitbang_end_state(TAP_SI);
	else
		bitbang_end_state(TAP_SD);

	bitbang_state_move();
	bitbang_end_state(saved_end_state);

	for (bit_cnt = 0; bit_cnt < scan_size; bit_cnt++)
	{
		/* if we're just reading the scan, but don't care about the output
		 * default to outputting 'low', this also makes valgrind traces more readable,
		 * as it removes the dependency on an uninitialised value
		 */ 
		if ((type != SCAN_IN) && ((buffer[bit_cnt/8] >> (bit_cnt % 8)) & 0x1)) {
			bitbang_interface->write(0, (bit_cnt==scan_size-1) ? 1 : 0, 1);
			bitbang_interface->write(1, (bit_cnt==scan_size-1) ? 1 : 0, 1);
		} else {
			bitbang_interface->write(0, (bit_cnt==scan_size-1) ? 1 : 0, 0);
			bitbang_interface->write(1, (bit_cnt==scan_size-1) ? 1 : 0, 0);
		}
		
		if (type != SCAN_OUT)
		{
			if (bitbang_interface->read())
				buffer[(bit_cnt)/8] |= 1 << ((bit_cnt) % 8);
			else
				buffer[(bit_cnt)/8] &= ~(1 << ((bit_cnt) % 8));
		}
	}
	
	/* Exit1 -> Pause */
	bitbang_interface->write(0, 0, 0);
	bitbang_interface->write(1, 0, 0);
	
	if (ir_scan)
		cur_state = TAP_PI;
	else
		cur_state = TAP_PD;
	
	if (cur_state != end_state)
		bitbang_state_move();
}

int bitbang_execute_queue(void)
{
	jtag_command_t *cmd = jtag_command_queue; /* currently processed command */
	int scan_size;
	enum scan_type type;
	u8 *buffer;
	
	if (!bitbang_interface)
	{
		ERROR("BUG: Bitbang interface called, but not yet initialized");
		exit(-1);
	}
		
	while (cmd)
	{
		switch (cmd->type)
		{
			case JTAG_END_STATE:
#ifdef _DEBUG_JTAG_IO_
				DEBUG("end_state: %i", cmd->cmd.end_state->end_state);
#endif
				if (cmd->cmd.end_state->end_state != -1)
					bitbang_end_state(cmd->cmd.end_state->end_state);
				break;
			case JTAG_RESET:
#ifdef _DEBUG_JTAG_IO_
				DEBUG("reset trst: %i srst %i", cmd->cmd.reset->trst, cmd->cmd.reset->srst);
#endif
				if (cmd->cmd.reset->trst == 1)
				{
					cur_state = TAP_TLR;
				}
				bitbang_interface->reset(cmd->cmd.reset->trst, cmd->cmd.reset->srst);
				break;
			case JTAG_RUNTEST:
#ifdef _DEBUG_JTAG_IO_
				DEBUG("runtest %i cycles, end in %i", cmd->cmd.runtest->num_cycles, cmd->cmd.runtest->end_state);
#endif
				if (cmd->cmd.runtest->end_state != -1)
					bitbang_end_state(cmd->cmd.runtest->end_state);
				bitbang_runtest(cmd->cmd.runtest->num_cycles);
				break;
			case JTAG_STATEMOVE:
#ifdef _DEBUG_JTAG_IO_
				DEBUG("statemove end in %i", cmd->cmd.statemove->end_state);
#endif
				if (cmd->cmd.statemove->end_state != -1)
					bitbang_end_state(cmd->cmd.statemove->end_state);
				bitbang_state_move();
				break;
			case JTAG_PATHMOVE:
#ifdef _DEBUG_JTAG_IO_
				DEBUG("pathmove: %i states, end in %i", cmd->cmd.pathmove->num_states, cmd->cmd.pathmove->path[cmd->cmd.pathmove->num_states - 1]);
#endif
				bitbang_path_move(cmd->cmd.pathmove);
				break;
			case JTAG_SCAN:
#ifdef _DEBUG_JTAG_IO_
				DEBUG("scan end in %i", cmd->cmd.scan->end_state);
#endif
				if (cmd->cmd.scan->end_state != -1)
					bitbang_end_state(cmd->cmd.scan->end_state);
				scan_size = jtag_build_buffer(cmd->cmd.scan, &buffer);
				type = jtag_scan_type(cmd->cmd.scan);
				bitbang_scan(cmd->cmd.scan->ir_scan, type, buffer, scan_size);
				if (jtag_read_buffer(buffer, cmd->cmd.scan) != ERROR_OK)
					return ERROR_JTAG_QUEUE_FAILED;
				if (buffer)
					free(buffer);
				break;
			case JTAG_SLEEP:
#ifdef _DEBUG_JTAG_IO_
				DEBUG("sleep %i", cmd->cmd.sleep->us);
#endif
				jtag_sleep(cmd->cmd.sleep->us);
				break;
			default:
				ERROR("BUG: unknown JTAG command type encountered");
				exit(-1);
		}
		cmd = cmd->next;
	}
	
	return ERROR_OK;
}