openocd/src/jtag/drivers/dummy.c

163 lines
4.2 KiB
C

/***************************************************************************
* Copyright (C) 2008 by Øyvind 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., *
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. *
***************************************************************************/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include <jtag/interface.h>
#include "bitbang.h"
#include "hello.h"
/* my private tap controller state, which tracks state for calling code */
static tap_state_t dummy_state = TAP_RESET;
static int dummy_clock; /* edge detector */
static int clock_count; /* count clocks in any stable state, only stable states */
static uint32_t dummy_data;
static int dummy_read(void)
{
int data = 1 & dummy_data;
dummy_data = (dummy_data >> 1) | (1 << 31);
return data;
}
static void dummy_write(int tck, int tms, int tdi)
{
/* TAP standard: "state transitions occur on rising edge of clock" */
if (tck != dummy_clock) {
if (tck) {
tap_state_t old_state = dummy_state;
dummy_state = tap_state_transition(old_state, tms);
if (old_state != dummy_state) {
if (clock_count) {
LOG_DEBUG("dummy_tap: %d stable clocks", clock_count);
clock_count = 0;
}
LOG_DEBUG("dummy_tap: %s", tap_state_name(dummy_state));
#if defined(DEBUG)
if (dummy_state == TAP_DRCAPTURE)
dummy_data = 0x01255043;
#endif
} else {
/* this is a stable state clock edge, no change of state here,
* simply increment clock_count for subsequent logging
*/
++clock_count;
}
}
dummy_clock = tck;
}
}
static void dummy_reset(int trst, int srst)
{
dummy_clock = 0;
if (trst || (srst && (jtag_get_reset_config() & RESET_SRST_PULLS_TRST)))
dummy_state = TAP_RESET;
LOG_DEBUG("reset to: %s", tap_state_name(dummy_state));
}
static void dummy_led(int on)
{
}
static struct bitbang_interface dummy_bitbang = {
.read = &dummy_read,
.write = &dummy_write,
.reset = &dummy_reset,
.blink = &dummy_led,
};
static int dummy_khz(int khz, int *jtag_speed)
{
if (khz == 0)
*jtag_speed = 0;
else
*jtag_speed = 64000/khz;
return ERROR_OK;
}
static int dummy_speed_div(int speed, int *khz)
{
if (speed == 0)
*khz = 0;
else
*khz = 64000/speed;
return ERROR_OK;
}
static int dummy_speed(int speed)
{
return ERROR_OK;
}
static int dummy_init(void)
{
bitbang_interface = &dummy_bitbang;
return ERROR_OK;
}
static int dummy_quit(void)
{
return ERROR_OK;
}
static const struct command_registration dummy_command_handlers[] = {
{
.name = "dummy",
.mode = COMMAND_ANY,
.help = "dummy interface driver commands",
.chain = hello_command_handlers,
},
COMMAND_REGISTRATION_DONE,
};
/* The dummy driver is used to easily check the code path
* where the target is unresponsive.
*/
struct jtag_interface dummy_interface = {
.name = "dummy",
.supported = DEBUG_CAP_TMS_SEQ,
.commands = dummy_command_handlers,
.transports = jtag_only,
.execute_queue = &bitbang_execute_queue,
.speed = &dummy_speed,
.khz = &dummy_khz,
.speed_div = &dummy_speed_div,
.init = &dummy_init,
.quit = &dummy_quit,
};