1 /***************************************************************************
2 * Copyright (C) 2008 by Øyvind Harboe *
3 * oyvind.harboe@zylin.com *
5 * This program is free software; you can redistribute it and/or modify *
6 * it under the terms of the GNU General Public License as published by *
7 * the Free Software Foundation; either version 2 of the License, or *
8 * (at your option) any later version. *
10 * This program is distributed in the hope that it will be useful, *
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of *
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the *
13 * GNU General Public License for more details. *
15 * You should have received a copy of the GNU General Public License *
16 * along with this program; if not, write to the *
17 * Free Software Foundation, Inc., *
18 * 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. *
19 ***************************************************************************/
24 #include "interface.h"
29 /* my private tap controller state, which tracks state for calling code */
30 static tap_state_t dummy_state = TAP_RESET;
32 static int dummy_clock; /* edge detector */
34 static int clock_count; /* count clocks in any stable state, only stable states */
36 static uint32_t dummy_data;
39 static int dummy_read(void)
41 int data = 1 & dummy_data;
42 dummy_data = (dummy_data >> 1) | (1 << 31);
47 static void dummy_write(int tck, int tms, int tdi)
49 /* TAP standard: "state transitions occur on rising edge of clock" */
50 if (tck != dummy_clock)
54 tap_state_t old_state = dummy_state;
55 dummy_state = tap_state_transition(old_state, tms);
57 if (old_state != dummy_state)
61 LOG_DEBUG("dummy_tap: %d stable clocks", clock_count);
65 LOG_DEBUG("dummy_tap: %s", tap_state_name(dummy_state));
68 if (dummy_state == TAP_DRCAPTURE)
69 dummy_data = 0x01255043;
74 /* this is a stable state clock edge, no change of state here,
75 * simply increment clock_count for subsequent logging
84 static void dummy_reset(int trst, int srst)
88 if (trst || (srst && (jtag_get_reset_config() & RESET_SRST_PULLS_TRST)))
89 dummy_state = TAP_RESET;
91 LOG_DEBUG("reset to: %s", tap_state_name(dummy_state));
94 static void dummy_led(int on)
98 static struct bitbang_interface dummy_bitbang = {
100 .write = &dummy_write,
101 .reset = &dummy_reset,
106 static int dummy_khz(int khz, int *jtag_speed)
114 *jtag_speed = 64000/khz;
119 static int dummy_speed_div(int speed, int *khz)
133 static int dummy_speed(int speed)
138 static int dummy_init(void)
140 bitbang_interface = &dummy_bitbang;
145 static int dummy_quit(void)
150 static const struct command_registration dummy_command_handlers[] = {
154 .help = "dummy interface driver commands",
156 .chain = hello_command_handlers,
158 COMMAND_REGISTRATION_DONE,
161 /* The dummy driver is used to easily check the code path
162 * where the target is unresponsive.
164 struct jtag_interface dummy_interface = {
167 .commands = dummy_command_handlers,
169 .execute_queue = &bitbang_execute_queue,
171 .speed = &dummy_speed,
173 .speed_div = &dummy_speed_div,