1 /***************************************************************************
2 * Copyright (C) 2005 by Dominic Rath *
3 * Dominic.Rath@gmx.de *
5 * Copyright (C) 2007,2008 Øyvind Harboe *
6 * oyvind.harboe@zylin.com *
8 * This program is free software; you can redistribute it and/or modify *
9 * it under the terms of the GNU General Public License as published by *
10 * the Free Software Foundation; either version 2 of the License, or *
11 * (at your option) any later version. *
13 * This program is distributed in the hope that it will be useful, *
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of *
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the *
16 * GNU General Public License for more details. *
18 * You should have received a copy of the GNU General Public License *
19 * along with this program; if not, write to the *
20 * Free Software Foundation, Inc., *
21 * 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. *
22 ***************************************************************************/
29 /* project specific includes */
33 #include "configuration.h"
40 bitbang_interface_t *bitbang_interface;
42 /* DANGER!!!! clock absolutely *MUST* be 0 in idle or reset won't work!
44 * Set this to 1 and str912 reset halt will fail.
46 * If someone can submit a patch with an explanation it will be greatly
47 * appreciated, but as far as I can tell (ØH) DCLK is generated upon
48 * clk=0 in TAP_IDLE. Good luck deducing that from the ARM documentation!
49 * The ARM documentation uses the term "DCLK is asserted while in the TAP_IDLE
50 * state". With hardware there is no such thing as *while* in a state. There
51 * are only edges. So clk => 0 is in fact a very subtle state transition that
52 * happens *while* in the TAP_IDLE state. "#&¤"#¤&"#&"#&
54 * For "reset halt" the last thing that happens before srst is asserted
55 * is that the breakpoint is set up. If DCLK is not wiggled one last
56 * time before the reset, then the breakpoint is not set up and
57 * "reset halt" will fail to halt.
60 #define CLOCK_IDLE() 0
62 int bitbang_execute_queue(void);
64 /* The bitbang driver leaves the TCK 0 when in idle */
66 void bitbang_end_state(enum tap_state state)
68 if (tap_move_map[state] != -1)
72 LOG_ERROR("BUG: %i is not a valid end state", state);
77 void bitbang_state_move(void) {
80 u8 tms_scan = TAP_MOVE(cur_state, end_state);
82 for (i = 0; i < 7; i++)
84 tms = (tms_scan >> i) & 1;
85 bitbang_interface->write(0, tms, 0);
86 bitbang_interface->write(1, tms, 0);
88 bitbang_interface->write(CLOCK_IDLE(), tms, 0);
90 cur_state = end_state;
93 void bitbang_path_move(pathmove_command_t *cmd)
95 int num_states = cmd->num_states;
102 if (tap_transitions[cur_state].low == cmd->path[state_count])
106 else if (tap_transitions[cur_state].high == cmd->path[state_count])
112 LOG_ERROR("BUG: %s -> %s isn't a valid TAP transition", jtag_state_name(cur_state), jtag_state_name(cmd->path[state_count]));
116 bitbang_interface->write(0, tms, 0);
117 bitbang_interface->write(1, tms, 0);
119 cur_state = cmd->path[state_count];
124 bitbang_interface->write(CLOCK_IDLE(), tms, 0);
126 end_state = cur_state;
129 void bitbang_runtest(int num_cycles)
133 enum tap_state saved_end_state = end_state;
135 /* only do a state_move when we're not already in IDLE */
136 if (cur_state != TAP_IDLE)
138 bitbang_end_state(TAP_IDLE);
139 bitbang_state_move();
142 /* execute num_cycles */
143 for (i = 0; i < num_cycles; i++)
145 bitbang_interface->write(0, 0, 0);
146 bitbang_interface->write(1, 0, 0);
148 bitbang_interface->write(CLOCK_IDLE(), 0, 0);
150 /* finish in end_state */
151 bitbang_end_state(saved_end_state);
152 if (cur_state != end_state)
153 bitbang_state_move();
156 void bitbang_scan(int ir_scan, enum scan_type type, u8 *buffer, int scan_size)
158 enum tap_state saved_end_state = end_state;
161 if (!((!ir_scan && (cur_state == TAP_DRSHIFT)) || (ir_scan && (cur_state == TAP_IRSHIFT))))
164 bitbang_end_state(TAP_IRSHIFT);
166 bitbang_end_state(TAP_DRSHIFT);
168 bitbang_state_move();
169 bitbang_end_state(saved_end_state);
172 for (bit_cnt = 0; bit_cnt < scan_size; bit_cnt++)
175 int tms=(bit_cnt==scan_size-1) ? 1 : 0;
178 int bcval=1<<(bit_cnt % 8);
180 /* if we're just reading the scan, but don't care about the output
181 * default to outputting 'low', this also makes valgrind traces more readable,
182 * as it removes the dependency on an uninitialised value
185 if ((type != SCAN_IN) && (buffer[bytec] & bcval))
188 bitbang_interface->write(0, tms, tdi);
191 val=bitbang_interface->read();
193 bitbang_interface->write(1, tms, tdi);
195 if (type != SCAN_OUT)
198 buffer[bytec] |= bcval;
200 buffer[bytec] &= ~bcval;
204 /* TAP_DRSHIFT & TAP_IRSHIFT are illegal end states, so we always transition to the pause
205 * state which is a legal stable state from which statemove will work.
209 bitbang_interface->write(0, 0, 0);
210 bitbang_interface->write(1, 0, 0);
211 bitbang_interface->write(CLOCK_IDLE(), 0, 0);
214 cur_state = TAP_IRPAUSE;
216 cur_state = TAP_DRPAUSE;
218 if (cur_state != end_state)
219 bitbang_state_move();
222 int bitbang_execute_queue(void)
224 jtag_command_t *cmd = jtag_command_queue; /* currently processed command */
230 if (!bitbang_interface)
232 LOG_ERROR("BUG: Bitbang interface called, but not yet initialized");
236 /* return ERROR_OK, unless a jtag_read_buffer returns a failed check
237 * that wasn't handled by a caller-provided error handler
241 if(bitbang_interface->blink)
242 bitbang_interface->blink(1);
249 #ifdef _DEBUG_JTAG_IO_
250 LOG_DEBUG("end_state: %i", cmd->cmd.end_state->end_state);
252 if (cmd->cmd.end_state->end_state != -1)
253 bitbang_end_state(cmd->cmd.end_state->end_state);
256 #ifdef _DEBUG_JTAG_IO_
257 LOG_DEBUG("reset trst: %i srst %i", cmd->cmd.reset->trst, cmd->cmd.reset->srst);
259 if ((cmd->cmd.reset->trst == 1) || (cmd->cmd.reset->srst && (jtag_reset_config & RESET_SRST_PULLS_TRST)))
261 cur_state = TAP_RESET;
263 bitbang_interface->reset(cmd->cmd.reset->trst, cmd->cmd.reset->srst);
266 #ifdef _DEBUG_JTAG_IO_
267 LOG_DEBUG("runtest %i cycles, end in %i", cmd->cmd.runtest->num_cycles, cmd->cmd.runtest->end_state);
269 if (cmd->cmd.runtest->end_state != -1)
270 bitbang_end_state(cmd->cmd.runtest->end_state);
271 bitbang_runtest(cmd->cmd.runtest->num_cycles);
274 #ifdef _DEBUG_JTAG_IO_
275 LOG_DEBUG("statemove end in %i", cmd->cmd.statemove->end_state);
277 if (cmd->cmd.statemove->end_state != -1)
278 bitbang_end_state(cmd->cmd.statemove->end_state);
279 bitbang_state_move();
282 #ifdef _DEBUG_JTAG_IO_
283 LOG_DEBUG("pathmove: %i states, end in %i", cmd->cmd.pathmove->num_states, cmd->cmd.pathmove->path[cmd->cmd.pathmove->num_states - 1]);
285 bitbang_path_move(cmd->cmd.pathmove);
288 #ifdef _DEBUG_JTAG_IO_
289 LOG_DEBUG("%s scan end in %i", (cmd->cmd.scan->ir_scan) ? "IR" : "DR", cmd->cmd.scan->end_state);
291 if (cmd->cmd.scan->end_state != -1)
292 bitbang_end_state(cmd->cmd.scan->end_state);
293 scan_size = jtag_build_buffer(cmd->cmd.scan, &buffer);
294 type = jtag_scan_type(cmd->cmd.scan);
295 bitbang_scan(cmd->cmd.scan->ir_scan, type, buffer, scan_size);
296 if (jtag_read_buffer(buffer, cmd->cmd.scan) != ERROR_OK)
297 retval = ERROR_JTAG_QUEUE_FAILED;
302 #ifdef _DEBUG_JTAG_IO_
303 LOG_DEBUG("sleep %i", cmd->cmd.sleep->us);
305 jtag_sleep(cmd->cmd.sleep->us);
308 LOG_ERROR("BUG: unknown JTAG command type encountered");
313 if(bitbang_interface->blink)
314 bitbang_interface->blink(0);