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;
43 /* DANGER!!!! clock absolutely *MUST* be 0 in idle or reset won't work!
45 * Set this to 1 and str912 reset halt will fail.
47 * If someone can submit a patch with an explanation it will be greatly
48 * appreciated, but as far as I can tell (ØH) DCLK is generated upon
49 * clk=0 in TAP_IDLE. Good luck deducing that from the ARM documentation!
50 * The ARM documentation uses the term "DCLK is asserted while in the TAP_IDLE
51 * state". With hardware there is no such thing as *while* in a state. There
52 * are only edges. So clk => 0 is in fact a very subtle state transition that
53 * happens *while* in the TAP_IDLE state. "#&¤"#¤&"#&"#&
55 * For "reset halt" the last thing that happens before srst is asserted
56 * is that the breakpoint is set up. If DCLK is not wiggled one last
57 * time before the reset, then the breakpoint is not set up and
58 * "reset halt" will fail to halt.
61 #define CLOCK_IDLE() 0
63 int bitbang_execute_queue(void);
65 /* The bitbang driver leaves the TCK 0 when in idle */
67 void bitbang_end_state(enum tap_state state)
69 if (tap_move_map[state] != -1)
73 LOG_ERROR("BUG: %i is not a valid end state", state);
78 void bitbang_state_move(void) {
81 u8 tms_scan = TAP_MOVE(cur_state, end_state);
83 for (i = 0; i < 7; i++)
85 tms = (tms_scan >> i) & 1;
86 bitbang_interface->write(0, tms, 0);
87 bitbang_interface->write(1, tms, 0);
89 bitbang_interface->write(CLOCK_IDLE(), tms, 0);
91 cur_state = end_state;
94 void bitbang_path_move(pathmove_command_t *cmd)
96 int num_states = cmd->num_states;
103 if (tap_transitions[cur_state].low == cmd->path[state_count])
107 else if (tap_transitions[cur_state].high == cmd->path[state_count])
113 LOG_ERROR("BUG: %s -> %s isn't a valid TAP transition", tap_state_strings[cur_state], tap_state_strings[cmd->path[state_count]]);
117 bitbang_interface->write(0, tms, 0);
118 bitbang_interface->write(1, tms, 0);
120 cur_state = cmd->path[state_count];
125 bitbang_interface->write(CLOCK_IDLE(), tms, 0);
127 end_state = cur_state;
130 void bitbang_runtest(int num_cycles)
134 enum tap_state saved_end_state = end_state;
136 /* only do a state_move when we're not already in IDLE */
137 if (cur_state != TAP_IDLE)
139 bitbang_end_state(TAP_IDLE);
140 bitbang_state_move();
143 /* execute num_cycles */
144 for (i = 0; i < num_cycles; i++)
146 bitbang_interface->write(0, 0, 0);
147 bitbang_interface->write(1, 0, 0);
149 bitbang_interface->write(CLOCK_IDLE(), 0, 0);
151 /* finish in end_state */
152 bitbang_end_state(saved_end_state);
153 if (cur_state != end_state)
154 bitbang_state_move();
157 void bitbang_scan(int ir_scan, enum scan_type type, u8 *buffer, int scan_size)
159 enum tap_state saved_end_state = end_state;
162 if (!((!ir_scan && (cur_state == TAP_DRSHIFT)) || (ir_scan && (cur_state == TAP_IRSHIFT))))
165 bitbang_end_state(TAP_IRSHIFT);
167 bitbang_end_state(TAP_DRSHIFT);
169 bitbang_state_move();
170 bitbang_end_state(saved_end_state);
173 for (bit_cnt = 0; bit_cnt < scan_size; bit_cnt++)
176 int tms=(bit_cnt==scan_size-1) ? 1 : 0;
179 int bcval=1<<(bit_cnt % 8);
181 /* if we're just reading the scan, but don't care about the output
182 * default to outputting 'low', this also makes valgrind traces more readable,
183 * as it removes the dependency on an uninitialised value
186 if ((type != SCAN_IN) && (buffer[bytec] & bcval))
189 bitbang_interface->write(0, tms, tdi);
192 val=bitbang_interface->read();
194 bitbang_interface->write(1, tms, tdi);
196 if (type != SCAN_OUT)
199 buffer[bytec] |= bcval;
201 buffer[bytec] &= ~bcval;
205 /* TAP_DRSHIFT & TAP_IRSHIFT are illegal end states, so we always transition to the pause
206 * state which is a legal stable state from which statemove will work.
210 bitbang_interface->write(0, 0, 0);
211 bitbang_interface->write(1, 0, 0);
212 bitbang_interface->write(CLOCK_IDLE(), 0, 0);
215 cur_state = TAP_IRPAUSE;
217 cur_state = TAP_DRPAUSE;
219 if (cur_state != end_state)
220 bitbang_state_move();
223 int bitbang_execute_queue(void)
225 jtag_command_t *cmd = jtag_command_queue; /* currently processed command */
231 if (!bitbang_interface)
233 LOG_ERROR("BUG: Bitbang interface called, but not yet initialized");
237 /* return ERROR_OK, unless a jtag_read_buffer returns a failed check
238 * that wasn't handled by a caller-provided error handler
242 if(bitbang_interface->blink)
243 bitbang_interface->blink(1);
250 #ifdef _DEBUG_JTAG_IO_
251 LOG_DEBUG("end_state: %i", cmd->cmd.end_state->end_state);
253 if (cmd->cmd.end_state->end_state != -1)
254 bitbang_end_state(cmd->cmd.end_state->end_state);
257 #ifdef _DEBUG_JTAG_IO_
258 LOG_DEBUG("reset trst: %i srst %i", cmd->cmd.reset->trst, cmd->cmd.reset->srst);
260 if ((cmd->cmd.reset->trst == 1) || (cmd->cmd.reset->srst && (jtag_reset_config & RESET_SRST_PULLS_TRST)))
262 cur_state = TAP_RESET;
264 bitbang_interface->reset(cmd->cmd.reset->trst, cmd->cmd.reset->srst);
267 #ifdef _DEBUG_JTAG_IO_
268 LOG_DEBUG("runtest %i cycles, end in %i", cmd->cmd.runtest->num_cycles, cmd->cmd.runtest->end_state);
270 if (cmd->cmd.runtest->end_state != -1)
271 bitbang_end_state(cmd->cmd.runtest->end_state);
272 bitbang_runtest(cmd->cmd.runtest->num_cycles);
275 #ifdef _DEBUG_JTAG_IO_
276 LOG_DEBUG("statemove end in %i", cmd->cmd.statemove->end_state);
278 if (cmd->cmd.statemove->end_state != -1)
279 bitbang_end_state(cmd->cmd.statemove->end_state);
280 bitbang_state_move();
283 #ifdef _DEBUG_JTAG_IO_
284 LOG_DEBUG("pathmove: %i states, end in %i", cmd->cmd.pathmove->num_states, cmd->cmd.pathmove->path[cmd->cmd.pathmove->num_states - 1]);
286 bitbang_path_move(cmd->cmd.pathmove);
289 #ifdef _DEBUG_JTAG_IO_
290 LOG_DEBUG("%s scan end in %i", (cmd->cmd.scan->ir_scan) ? "IR" : "DR", cmd->cmd.scan->end_state);
292 if (cmd->cmd.scan->end_state != -1)
293 bitbang_end_state(cmd->cmd.scan->end_state);
294 scan_size = jtag_build_buffer(cmd->cmd.scan, &buffer);
295 type = jtag_scan_type(cmd->cmd.scan);
296 bitbang_scan(cmd->cmd.scan->ir_scan, type, buffer, scan_size);
297 if (jtag_read_buffer(buffer, cmd->cmd.scan) != ERROR_OK)
298 retval = ERROR_JTAG_QUEUE_FAILED;
303 #ifdef _DEBUG_JTAG_IO_
304 LOG_DEBUG("sleep %i", cmd->cmd.sleep->us);
306 jtag_sleep(cmd->cmd.sleep->us);
309 LOG_ERROR("BUG: unknown JTAG command type encountered");
314 if(bitbang_interface->blink)
315 bitbang_interface->blink(0);