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, see <http://www.gnu.org/licenses/>. *
17 ***************************************************************************/
23 #include <jtag/interface.h>
27 /* my private tap controller state, which tracks state for calling code */
28 static tap_state_t dummy_state
= TAP_RESET
;
30 static int dummy_clock
; /* edge detector */
32 static int clock_count
; /* count clocks in any stable state, only stable states */
34 static uint32_t dummy_data
;
36 static int dummy_read(void)
38 int data
= 1 & dummy_data
;
39 dummy_data
= (dummy_data
>> 1) | (1 << 31);
43 static void dummy_write(int tck
, int tms
, int tdi
)
45 /* TAP standard: "state transitions occur on rising edge of clock" */
46 if (tck
!= dummy_clock
) {
48 tap_state_t old_state
= dummy_state
;
49 dummy_state
= tap_state_transition(old_state
, tms
);
51 if (old_state
!= dummy_state
) {
53 LOG_DEBUG("dummy_tap: %d stable clocks", clock_count
);
57 LOG_DEBUG("dummy_tap: %s", tap_state_name(dummy_state
));
60 if (dummy_state
== TAP_DRCAPTURE
)
61 dummy_data
= 0x01255043;
64 /* this is a stable state clock edge, no change of state here,
65 * simply increment clock_count for subsequent logging
74 static void dummy_reset(int trst
, int srst
)
78 if (trst
|| (srst
&& (jtag_get_reset_config() & RESET_SRST_PULLS_TRST
)))
79 dummy_state
= TAP_RESET
;
81 LOG_DEBUG("reset to: %s", tap_state_name(dummy_state
));
84 static void dummy_led(int on
)
88 static struct bitbang_interface dummy_bitbang
= {
90 .write
= &dummy_write
,
91 .reset
= &dummy_reset
,
95 static int dummy_khz(int khz
, int *jtag_speed
)
100 *jtag_speed
= 64000/khz
;
104 static int dummy_speed_div(int speed
, int *khz
)
114 static int dummy_speed(int speed
)
119 static int dummy_init(void)
121 bitbang_interface
= &dummy_bitbang
;
126 static int dummy_quit(void)
131 static const struct command_registration dummy_command_handlers
[] = {
135 .help
= "dummy interface driver commands",
137 .chain
= hello_command_handlers
,
139 COMMAND_REGISTRATION_DONE
,
142 /* The dummy driver is used to easily check the code path
143 * where the target is unresponsive.
145 struct jtag_interface dummy_interface
= {
148 .supported
= DEBUG_CAP_TMS_SEQ
,
149 .commands
= dummy_command_handlers
,
150 .transports
= jtag_only
,
152 .execute_queue
= &bitbang_execute_queue
,
154 .speed
= &dummy_speed
,
156 .speed_div
= &dummy_speed_div
,