be61b37d27b9cb566a3e06baa5052f96a5c078c9
[openocd.git] / src / jtag / drivers / dummy.c
1 /***************************************************************************
2 * Copyright (C) 2008 by √ėyvind Harboe *
3 * oyvind.harboe@zylin.com *
4 * *
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. *
9 * *
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. *
14 * *
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 ***************************************************************************/
20
21 #ifdef HAVE_CONFIG_H
22 #include "config.h"
23 #endif
24
25 #include <jtag/interface.h>
26 #include "bitbang.h"
27 #include "hello.h"
28
29 /* my private tap controller state, which tracks state for calling code */
30 static tap_state_t dummy_state = TAP_RESET;
31
32 static int dummy_clock; /* edge detector */
33
34 static int clock_count; /* count clocks in any stable state, only stable states */
35
36 static uint32_t dummy_data;
37
38 static int dummy_read(void)
39 {
40 int data = 1 & dummy_data;
41 dummy_data = (dummy_data >> 1) | (1 << 31);
42 return data;
43 }
44
45 static void dummy_write(int tck, int tms, int tdi)
46 {
47 /* TAP standard: "state transitions occur on rising edge of clock" */
48 if (tck != dummy_clock) {
49 if (tck) {
50 tap_state_t old_state = dummy_state;
51 dummy_state = tap_state_transition(old_state, tms);
52
53 if (old_state != dummy_state) {
54 if (clock_count) {
55 LOG_DEBUG("dummy_tap: %d stable clocks", clock_count);
56 clock_count = 0;
57 }
58
59 LOG_DEBUG("dummy_tap: %s", tap_state_name(dummy_state));
60
61 #if defined(DEBUG)
62 if (dummy_state == TAP_DRCAPTURE)
63 dummy_data = 0x01255043;
64 #endif
65 } else {
66 /* this is a stable state clock edge, no change of state here,
67 * simply increment clock_count for subsequent logging
68 */
69 ++clock_count;
70 }
71 }
72 dummy_clock = tck;
73 }
74 }
75
76 static void dummy_reset(int trst, int srst)
77 {
78 dummy_clock = 0;
79
80 if (trst || (srst && (jtag_get_reset_config() & RESET_SRST_PULLS_TRST)))
81 dummy_state = TAP_RESET;
82
83 LOG_DEBUG("reset to: %s", tap_state_name(dummy_state));
84 }
85
86 static void dummy_led(int on)
87 {
88 }
89
90 static struct bitbang_interface dummy_bitbang = {
91 .read = &dummy_read,
92 .write = &dummy_write,
93 .reset = &dummy_reset,
94 .blink = &dummy_led,
95 };
96
97 static int dummy_khz(int khz, int *jtag_speed)
98 {
99 if (khz == 0)
100 *jtag_speed = 0;
101 else
102 *jtag_speed = 64000/khz;
103 return ERROR_OK;
104 }
105
106 static int dummy_speed_div(int speed, int *khz)
107 {
108 if (speed == 0)
109 *khz = 0;
110 else
111 *khz = 64000/speed;
112
113 return ERROR_OK;
114 }
115
116 static int dummy_speed(int speed)
117 {
118 return ERROR_OK;
119 }
120
121 static int dummy_init(void)
122 {
123 bitbang_interface = &dummy_bitbang;
124
125 return ERROR_OK;
126 }
127
128 static int dummy_quit(void)
129 {
130 return ERROR_OK;
131 }
132
133 static const struct command_registration dummy_command_handlers[] = {
134 {
135 .name = "dummy",
136 .mode = COMMAND_ANY,
137 .help = "dummy interface driver commands",
138
139 .chain = hello_command_handlers,
140 },
141 COMMAND_REGISTRATION_DONE,
142 };
143
144 /* The dummy driver is used to easily check the code path
145 * where the target is unresponsive.
146 */
147 struct jtag_interface dummy_interface = {
148 .name = "dummy",
149
150 .supported = DEBUG_CAP_TMS_SEQ,
151 .commands = dummy_command_handlers,
152 .transports = jtag_only,
153
154 .execute_queue = &bitbang_execute_queue,
155
156 .speed = &dummy_speed,
157 .khz = &dummy_khz,
158 .speed_div = &dummy_speed_div,
159
160 .init = &dummy_init,
161 .quit = &dummy_quit,
162 };