WARNING! This is a very big and serious change to internals
[openocd/libswd.git] / src / jtag / jtag.h
blob5d926a8222b6ed2319b9294709449e52d066828e
1 /***************************************************************************
2 * Copyright (C) 2005 by Dominic Rath *
3 * Dominic.Rath@gmx.de *
4 * *
5 * Copyright (C) 2007-2010 Øyvind Harboe *
6 * oyvind.harboe@zylin.com *
7 * *
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. *
12 * *
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. *
17 * *
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 ***************************************************************************/
24 #ifndef JTAG_H
25 #define JTAG_H
27 #include <helper/binarybuffer.h>
28 #include <helper/log.h>
29 #include <transport/transport.h>
31 #ifdef _DEBUG_JTAG_IO_
32 #define DEBUG_JTAG_IO(expr ...) \
33 do { if (1) LOG_DEBUG(expr); } while (0)
34 #else
35 #define DEBUG_JTAG_IO(expr ...) \
36 do { if (0) LOG_DEBUG(expr); } while (0)
37 #endif
39 #ifndef DEBUG_JTAG_IOZ
40 #define DEBUG_JTAG_IOZ 64
41 #endif
43 /*-----</Macros>-------------------------------------------------*/
45 /**
46 * Defines JTAG Test Access Port states.
48 * These definitions were gleaned from the ARM7TDMI-S Technical
49 * Reference Manual and validated against several other ARM core
50 * technical manuals.
52 * FIXME some interfaces require specific numbers be used, as they
53 * are handed-off directly to their hardware implementations.
54 * Fix those drivers to map as appropriate ... then pick some
55 * sane set of numbers here (where 0/uninitialized == INVALID).
57 typedef enum tap_state {
58 TAP_INVALID = -1,
60 #if BUILD_ZY1000
61 /* These are the old numbers. Leave as-is for now... */
62 TAP_RESET = 0, TAP_IDLE = 8,
63 TAP_DRSELECT = 1, TAP_DRCAPTURE = 2, TAP_DRSHIFT = 3, TAP_DREXIT1 = 4,
64 TAP_DRPAUSE = 5, TAP_DREXIT2 = 6, TAP_DRUPDATE = 7,
65 TAP_IRSELECT = 9, TAP_IRCAPTURE = 10, TAP_IRSHIFT = 11, TAP_IREXIT1 = 12,
66 TAP_IRPAUSE = 13, TAP_IREXIT2 = 14, TAP_IRUPDATE = 15,
68 #else
69 /* Proper ARM recommended numbers */
70 TAP_DREXIT2 = 0x0,
71 TAP_DREXIT1 = 0x1,
72 TAP_DRSHIFT = 0x2,
73 TAP_DRPAUSE = 0x3,
74 TAP_IRSELECT = 0x4,
75 TAP_DRUPDATE = 0x5,
76 TAP_DRCAPTURE = 0x6,
77 TAP_DRSELECT = 0x7,
78 TAP_IREXIT2 = 0x8,
79 TAP_IREXIT1 = 0x9,
80 TAP_IRSHIFT = 0xa,
81 TAP_IRPAUSE = 0xb,
82 TAP_IDLE = 0xc,
83 TAP_IRUPDATE = 0xd,
84 TAP_IRCAPTURE = 0xe,
85 TAP_RESET = 0x0f,
87 #endif
88 } tap_state_t;
90 /**
91 * Function tap_state_name
92 * Returns a string suitable for display representing the JTAG tap_state
94 const char *tap_state_name(tap_state_t state);
96 /** Provides user-friendly name lookup of TAP states. */
97 tap_state_t tap_state_by_name(const char *name);
99 /** The current TAP state of the pending JTAG command queue. */
100 extern tap_state_t cmd_queue_cur_state;
103 * This structure defines a single scan field in the scan. It provides
104 * fields for the field's width and pointers to scan input and output
105 * values.
107 * In addition, this structure includes a value and mask that is used by
108 * jtag_add_dr_scan_check() to validate the value that was scanned out.
110 struct scan_field {
111 /** The number of bits this field specifies (up to 32) */
112 int num_bits;
113 /** A pointer to value to be scanned into the device */
114 const uint8_t *out_value;
115 /** A pointer to a 32-bit memory location for data scanned out */
116 uint8_t *in_value;
118 /** The value used to check the data scanned out. */
119 uint8_t *check_value;
120 /** The mask to go with check_value */
121 uint8_t *check_mask;
124 struct jtag_tap {
125 const char *chip;
126 const char *tapname;
127 const char *dotted_name;
128 int abs_chain_position;
129 /** Is this TAP disabled after JTAG reset? */
130 bool disabled_after_reset;
131 /** Is this TAP currently enabled? */
132 bool enabled;
133 int ir_length; /**< size of instruction register */
134 uint32_t ir_capture_value;
135 uint8_t *expected; /**< Capture-IR expected value */
136 uint32_t ir_capture_mask;
137 uint8_t *expected_mask; /**< Capture-IR expected mask */
138 uint32_t idcode; /**< device identification code */
139 /** not all devices have idcode,
140 * we'll discover this during chain examination */
141 bool hasidcode;
143 /** Array of expected identification codes */
144 uint32_t *expected_ids;
145 /** Number of expected identification codes */
146 uint8_t expected_ids_cnt;
148 /** Flag saying whether to ignore version field in expected_ids[] */
149 bool ignore_version;
151 /** current instruction */
152 uint8_t *cur_instr;
153 /** Bypass register selected */
154 int bypass;
156 struct jtag_tap_event_action *event_action;
158 struct jtag_tap *next_tap;
159 /* dap instance if some null if no instance , initialized to 0 by calloc*/
160 struct adiv5_dap *dap;
161 /* private pointer to support none-jtag specific functions */
162 void *priv;
165 void jtag_tap_init(struct jtag_tap *tap);
166 void jtag_tap_free(struct jtag_tap *tap);
168 struct jtag_tap *jtag_all_taps(void);
169 const char *jtag_tap_name(const struct jtag_tap *tap);
170 struct jtag_tap *jtag_tap_by_string(const char* dotted_name);
171 struct jtag_tap *jtag_tap_by_jim_obj(Jim_Interp* interp, Jim_Obj *obj);
172 struct jtag_tap *jtag_tap_by_position(unsigned abs_position);
173 struct jtag_tap *jtag_tap_next_enabled(struct jtag_tap *p);
174 unsigned jtag_tap_count_enabled(void);
175 unsigned jtag_tap_count(void);
178 * - TRST_ASSERTED triggers two sets of callbacks, after operations to
179 * reset the scan chain -- via TMS+TCK signaling, or deasserting the
180 * nTRST signal -- are queued:
182 * + Callbacks in C code fire first, patching internal state
183 * + Then post-reset event scripts fire ... activating JTAG circuits
184 * via TCK cycles, exiting SWD mode via TMS sequences, etc
186 * During those callbacks, scan chain contents have not been validated.
187 * JTAG operations that address a specific TAP (primarily DR/IR scans)
188 * must *not* be queued.
190 * - TAP_EVENT_SETUP is reported after TRST_ASSERTED, and after the scan
191 * chain has been validated. JTAG operations including scans that
192 * target specific TAPs may be performed.
194 * - TAP_EVENT_ENABLE and TAP_EVENT_DISABLE implement TAP activation and
195 * deactivation outside the core using scripted code that understands
196 * the specific JTAG router type. They might be triggered indirectly
197 * from EVENT_SETUP operations.
199 enum jtag_event {
200 JTAG_TRST_ASSERTED,
201 JTAG_TAP_EVENT_SETUP,
202 JTAG_TAP_EVENT_ENABLE,
203 JTAG_TAP_EVENT_DISABLE,
206 struct jtag_tap_event_action {
207 /** The event for which this action will be triggered. */
208 enum jtag_event event;
209 /** The interpreter to use for evaluating the @c body. */
210 Jim_Interp *interp;
211 /** Contains a script to 'eval' when the @c event is triggered. */
212 Jim_Obj *body;
213 /* next action in linked list */
214 struct jtag_tap_event_action *next;
218 * Defines the function signature requide for JTAG event callback
219 * functions, which are added with jtag_register_event_callback()
220 * and removed jtag_unregister_event_callback().
221 * @param event The event to handle.
222 * @param prive A pointer to data that was passed to
223 * jtag_register_event_callback().
224 * @returns Must return ERROR_OK on success, or an error code on failure.
226 * @todo Change to return void or define a use for its return code.
228 typedef int (*jtag_event_handler_t)(enum jtag_event event, void *priv);
230 int jtag_register_event_callback(jtag_event_handler_t f, void *x);
231 int jtag_unregister_event_callback(jtag_event_handler_t f, void *x);
233 int jtag_call_event_callbacks(enum jtag_event event);
236 /** @returns The current JTAG speed setting. */
237 int jtag_get_speed(int *speed);
240 * Given a @a speed setting, use the interface @c speed_div callback to
241 * adjust the setting.
242 * @param speed The speed setting to convert back to readable KHz.
243 * @returns ERROR_OK if the interface has not been initialized or on success;
244 * otherwise, the error code produced by the @c speed_div callback.
246 int jtag_get_speed_readable(int *speed);
248 /** Attempt to configure the interface for the specified KHz. */
249 int jtag_config_khz(unsigned khz);
252 * Attempt to enable RTCK/RCLK. If that fails, fallback to the
253 * specified frequency.
255 int jtag_config_rclk(unsigned fallback_speed_khz);
257 /** Retreives the clock speed of the JTAG interface in KHz. */
258 unsigned jtag_get_speed_khz(void);
260 enum reset_types {
261 RESET_NONE = 0x0,
262 RESET_HAS_TRST = 0x1,
263 RESET_HAS_SRST = 0x2,
264 RESET_TRST_AND_SRST = 0x3,
265 RESET_SRST_PULLS_TRST = 0x4,
266 RESET_TRST_PULLS_SRST = 0x8,
267 RESET_TRST_OPEN_DRAIN = 0x10,
268 RESET_SRST_PUSH_PULL = 0x20,
269 RESET_SRST_NO_GATING = 0x40,
270 RESET_CNCT_UNDER_SRST = 0x80
273 enum reset_types jtag_get_reset_config(void);
274 void jtag_set_reset_config(enum reset_types type);
276 void jtag_set_nsrst_delay(unsigned delay);
277 unsigned jtag_get_nsrst_delay(void);
279 void jtag_set_ntrst_delay(unsigned delay);
280 unsigned jtag_get_ntrst_delay(void);
282 void jtag_set_nsrst_assert_width(unsigned delay);
283 unsigned jtag_get_nsrst_assert_width(void);
285 void jtag_set_ntrst_assert_width(unsigned delay);
286 unsigned jtag_get_ntrst_assert_width(void);
288 /** @returns The current state of TRST. */
289 int jtag_get_trst(void);
290 /** @returns The current state of SRST. */
291 int jtag_get_srst(void);
293 /** Enable or disable data scan verification checking. */
294 void jtag_set_verify(bool enable);
295 /** @returns True if data scan verification will be performed. */
296 bool jtag_will_verify(void);
298 /** Enable or disable verification of IR scan checking. */
299 void jtag_set_verify_capture_ir(bool enable);
300 /** @returns True if IR scan verification will be performed. */
301 bool jtag_will_verify_capture_ir(void);
303 /** Initialize debug adapter upon startup. */
304 int adapter_init(struct command_context *cmd_ctx);
306 /** Shutdown the debug adapter upon program exit. */
307 int adapter_quit(void);
309 /** Set ms to sleep after jtag_execute_queue() flushes queue. Debug purposes. */
310 void jtag_set_flush_queue_sleep(int ms);
313 * Initialize JTAG chain using only a RESET reset. If init fails,
314 * try reset + init.
316 extern int jtag_init(struct command_context *cmd_ctx);
317 extern int jtag_select(struct command_context *ctx);
318 extern int jtag_setup(struct command_context *ctx);
319 extern int jtag_setup_arm(struct command_context *ctx);
321 /** reset, then initialize JTAG chain */
322 int jtag_init_reset(struct command_context *cmd_ctx);
323 int jtag_register_commands(struct command_context *cmd_ctx);
324 int jtag_init_inner(struct command_context *cmd_ctx);
327 * @file
328 * The JTAG interface can be implemented with a software or hardware fifo.
330 * TAP_DRSHIFT and TAP_IRSHIFT are illegal end states; however,
331 * TAP_DRSHIFT/IRSHIFT can be emulated as end states, by using longer
332 * scans.
334 * Code that is relatively insensitive to the path taken through state
335 * machine (as long as it is JTAG compliant) can use @a endstate for
336 * jtag_add_xxx_scan(). Otherwise, the pause state must be specified as
337 * end state and a subsequent jtag_add_pathmove() must be issued.
341 * Generate an IR SCAN with a list of scan fields with one entry for
342 * each enabled TAP.
344 * If the input field list contains an instruction value for a TAP then
345 * that is used otherwise the TAP is set to bypass.
347 * TAPs for which no fields are passed are marked as bypassed for
348 * subsequent DR SCANs.
351 void jtag_add_ir_scan(struct jtag_tap *tap,
352 struct scan_field *fields, tap_state_t endstate);
354 * The same as jtag_add_ir_scan except no verification is performed out
355 * the output values.
357 void jtag_add_ir_scan_noverify(struct jtag_tap *tap,
358 const struct scan_field *fields, tap_state_t state);
360 * Scan out the bits in ir scan mode.
362 * If in_bits == NULL, discard incoming bits.
364 void jtag_add_plain_ir_scan(int num_bits, const uint8_t *out_bits, uint8_t *in_bits,
365 tap_state_t endstate);
368 * Generate a DR SCAN using the fields passed to the function.
369 * For connected TAPs, the function checks in_fields and uses fields
370 * specified there. For bypassed TAPs, the function generates a dummy
371 * 1-bit field. The bypass status of TAPs is set by jtag_add_ir_scan().
373 void jtag_add_dr_scan(struct jtag_tap *tap, int num_fields,
374 const struct scan_field *fields, tap_state_t endstate);
375 /** A version of jtag_add_dr_scan() that uses the check_value/mask fields */
376 void jtag_add_dr_scan_check(struct jtag_tap *tap, int num_fields,
377 struct scan_field *fields, tap_state_t endstate);
379 * Scan out the bits in ir scan mode.
381 * If in_bits == NULL, discard incoming bits.
383 void jtag_add_plain_dr_scan(int num_bits,
384 const uint8_t *out_bits, uint8_t *in_bits, tap_state_t endstate);
387 * Defines the type of data passed to the jtag_callback_t interface.
388 * The underlying type must allow storing an @c int or pointer type.
390 typedef intptr_t jtag_callback_data_t;
393 * Defines a simple JTAG callback that can allow conversions on data
394 * scanned in from an interface.
396 * This callback should only be used for conversion that cannot fail.
397 * For conversion types or checks that can fail, use the more complete
398 * variant: jtag_callback_t.
400 typedef void (*jtag_callback1_t)(jtag_callback_data_t data0);
402 /** A simpler version of jtag_add_callback4(). */
403 void jtag_add_callback(jtag_callback1_t, jtag_callback_data_t data0);
407 * Defines the interface of the JTAG callback mechanism. Such
408 * callbacks can be executed once the queue has been flushed.
410 * The JTAG queue can be executed synchronously or asynchronously.
411 * Typically for USB, the queue is executed asynchronously. For
412 * low-latency interfaces, the queue may be executed synchronously.
414 * The callback mechanism is very general and does not make many
415 * assumptions about what the callback does or what its arguments are.
416 * These callbacks are typically executed *after* the *entire* JTAG
417 * queue has been executed for e.g. USB interfaces, and they are
418 * guaranteeed to be invoked in the order that they were queued.
420 * If the execution of the queue fails before the callbacks, then --
421 * depending on driver implementation -- the callbacks may or may not be
422 * invoked.
424 * @todo Make that behavior consistent.
426 * @param data0 Typically used to point to the data to operate on.
427 * Frequently this will be the data clocked in during a shift operation.
428 * @param data1 An integer big enough to use as an @c int or a pointer.
429 * @param data2 An integer big enough to use as an @c int or a pointer.
430 * @param data3 An integer big enough to use as an @c int or a pointer.
431 * @returns an error code
433 typedef int (*jtag_callback_t)(jtag_callback_data_t data0,
434 jtag_callback_data_t data1,
435 jtag_callback_data_t data2,
436 jtag_callback_data_t data3);
439 * Run a TAP_RESET reset where the end state is TAP_RESET,
440 * regardless of the start state.
442 void jtag_add_tlr(void);
445 * Application code *must* assume that interfaces will
446 * implement transitions between states with different
447 * paths and path lengths through the state diagram. The
448 * path will vary across interface and also across versions
449 * of the same interface over time. Even if the OpenOCD code
450 * is unchanged, the actual path taken may vary over time
451 * and versions of interface firmware or PCB revisions.
453 * Use jtag_add_pathmove() when specific transition sequences
454 * are required.
456 * Do not use jtag_add_pathmove() unless you need to, but do use it
457 * if you have to.
459 * DANGER! If the target is dependent upon a particular sequence
460 * of transitions for things to work correctly(e.g. as a workaround
461 * for an errata that contradicts the JTAG standard), then pathmove
462 * must be used, even if some jtag interfaces happen to use the
463 * desired path. Worse, the jtag interface used for testing a
464 * particular implementation, could happen to use the "desired"
465 * path when transitioning to/from end
466 * state.
468 * A list of unambigious single clock state transitions, not
469 * all drivers can support this, but it is required for e.g.
470 * XScale and Xilinx support
472 * Note! TAP_RESET must not be used in the path!
474 * Note that the first on the list must be reachable
475 * via a single transition from the current state.
477 * All drivers are required to implement jtag_add_pathmove().
478 * However, if the pathmove sequence can not be precisely
479 * executed, an interface_jtag_add_pathmove() or jtag_execute_queue()
480 * must return an error. It is legal, but not recommended, that
481 * a driver returns an error in all cases for a pathmove if it
482 * can only implement a few transitions and therefore
483 * a partial implementation of pathmove would have little practical
484 * application.
486 * If an error occurs, jtag_error will contain one of these error codes:
487 * - ERROR_JTAG_NOT_STABLE_STATE -- The final state was not stable.
488 * - ERROR_JTAG_STATE_INVALID -- The path passed through TAP_RESET.
489 * - ERROR_JTAG_TRANSITION_INVALID -- The path includes invalid
490 * state transitions.
492 void jtag_add_pathmove(int num_states, const tap_state_t *path);
495 * jtag_add_statemove() moves from the current state to @a goal_state.
497 * @param goal_state The final TAP state.
498 * @return ERROR_OK on success, or an error code on failure.
500 * Moves from the current state to the goal \a state.
501 * Both states must be stable.
503 int jtag_add_statemove(tap_state_t goal_state);
506 * Goes to TAP_IDLE (if we're not already there), cycle
507 * precisely num_cycles in the TAP_IDLE state, after which move
508 * to @a endstate (unless it is also TAP_IDLE).
510 * @param num_cycles Number of cycles in TAP_IDLE state. This argument
511 * may be 0, in which case this routine will navigate to @a endstate
512 * via TAP_IDLE.
513 * @param endstate The final state.
515 void jtag_add_runtest(int num_cycles, tap_state_t endstate);
518 * A reset of the TAP state machine can be requested.
520 * Whether tms or trst reset is used depends on the capabilities of
521 * the target and jtag interface(reset_config command configures this).
523 * srst can driver a reset of the TAP state machine and vice
524 * versa
526 * Application code may need to examine value of jtag_reset_config
527 * to determine the proper codepath
529 * DANGER! Even though srst drives trst, trst might not be connected to
530 * the interface, and it might actually be *harmful* to assert trst in this case.
532 * This is why combinations such as "reset_config srst_only srst_pulls_trst"
533 * are supported.
535 * only req_tlr_or_trst and srst can have a transition for a
536 * call as the effects of transitioning both at the "same time"
537 * are undefined, but when srst_pulls_trst or vice versa,
538 * then trst & srst *must* be asserted together.
540 void jtag_add_reset(int req_tlr_or_trst, int srst);
542 void jtag_add_sleep(uint32_t us);
544 int jtag_add_tms_seq(unsigned nbits, const uint8_t *seq, enum tap_state t);
547 * Function jtag_add_clocks
548 * first checks that the state in which the clocks are to be issued is
549 * stable, then queues up num_cycles clocks for transmission.
551 void jtag_add_clocks(int num_cycles);
554 * For software FIFO implementations, the queued commands can be executed
555 * during this call or earlier. A sw queue might decide to push out
556 * some of the jtag_add_xxx() operations once the queue is "big enough".
558 * This fn will return an error code if any of the prior jtag_add_xxx()
559 * calls caused a failure, e.g. check failure. Note that it does not
560 * matter if the operation was executed *before* jtag_execute_queue(),
561 * jtag_execute_queue() will still return an error code.
563 * All jtag_add_xxx() calls that have in_handler != NULL will have been
564 * executed when this fn returns, but if what has been queued only
565 * clocks data out, without reading anything back, then JTAG could
566 * be running *after* jtag_execute_queue() returns. The API does
567 * not define a way to flush a hw FIFO that runs *after*
568 * jtag_execute_queue() returns.
570 * jtag_add_xxx() commands can either be executed immediately or
571 * at some time between the jtag_add_xxx() fn call and jtag_execute_queue().
573 int jtag_execute_queue(void);
575 /** same as jtag_execute_queue() but does not clear the error flag */
576 void jtag_execute_queue_noclear(void);
578 /** @returns the number of times the scan queue has been flushed */
579 int jtag_get_flush_queue_count(void);
581 /** Report Tcl event to all TAPs */
582 void jtag_notify_event(enum jtag_event);
584 /* can be implemented by hw + sw */
585 int jtag_power_dropout(int *dropout);
586 int jtag_srst_asserted(int *srst_asserted);
588 /* JTAG support functions */
591 * Execute jtag queue and check value with an optional mask.
592 * @param field Pointer to scan field.
593 * @param value Pointer to scan value.
594 * @param mask Pointer to scan mask; may be NULL.
595 * @returns Nothing, but calls jtag_set_error() on any error.
597 void jtag_check_value_mask(struct scan_field *field, uint8_t *value, uint8_t *mask);
599 void jtag_sleep(uint32_t us);
602 * The JTAG subsystem defines a number of error codes,
603 * using codes between -100 and -199.
605 #define ERROR_JTAG_INIT_FAILED (-100)
606 #define ERROR_JTAG_INVALID_INTERFACE (-101)
607 #define ERROR_JTAG_NOT_IMPLEMENTED (-102)
608 #define ERROR_JTAG_TRST_ASSERTED (-103)
609 #define ERROR_JTAG_QUEUE_FAILED (-104)
610 #define ERROR_JTAG_NOT_STABLE_STATE (-105)
611 #define ERROR_JTAG_DEVICE_ERROR (-107)
612 #define ERROR_JTAG_STATE_INVALID (-108)
613 #define ERROR_JTAG_TRANSITION_INVALID (-109)
614 #define ERROR_JTAG_INIT_SOFT_FAIL (-110)
617 * jtag_add_dr_out() is a version of jtag_add_dr_scan() which
618 * only scans data out. It operates on 32 bit integers instead
619 * of 8 bit, which makes it a better impedance match with
620 * the calling code which often operate on 32 bit integers.
622 * Current or end_state can not be TAP_RESET. end_state can be TAP_INVALID
624 * num_bits[i] is the number of bits to clock out from value[i] LSB first.
626 * If the device is in bypass, then that is an error condition in
627 * the caller code that is not detected by this fn, whereas
628 * jtag_add_dr_scan() does detect it. Similarly if the device is not in
629 * bypass, data must be passed to it.
631 * If anything fails, then jtag_error will be set and jtag_execute() will
632 * return an error. There is no way to determine if there was a failure
633 * during this function call.
635 * This is an inline fn to speed up embedded hosts. Also note that
636 * interface_jtag_add_dr_out() can be a *small* inline function for
637 * embedded hosts.
639 * There is no jtag_add_dr_outin() version of this fn that also allows
640 * clocking data back in. Patches gladly accepted!
644 * Set the current JTAG core execution error, unless one was set
645 * by a previous call previously. Driver or application code must
646 * use jtag_error_clear to reset jtag_error once this routine has been
647 * called with a non-zero error code.
649 void jtag_set_error(int error);
651 * Resets jtag_error to ERROR_OK, returning its previous value.
652 * @returns The previous value of @c jtag_error.
654 int jtag_error_clear(void);
657 * Return true if it's safe for a background polling task to access the
658 * JTAG scan chain. Polling may be explicitly disallowed, and is also
659 * unsafe while nTRST is active or the JTAG clock is gated off.
661 bool is_jtag_poll_safe(void);
664 * Return flag reporting whether JTAG polling is disallowed.
666 bool jtag_poll_get_enabled(void);
669 * Assign flag reporting whether JTAG polling is disallowed.
671 void jtag_poll_set_enabled(bool value);
674 /* The minidriver may have inline versions of some of the low
675 * level APIs that are used in inner loops. */
676 #include <jtag/minidriver.h>
678 extern oocd_transport_t jtag_transport;
679 bool transport_is_jtag(void);
681 int jim_jtag_newtap(Jim_Interp *interp, int argc, Jim_Obj *const *argv);
683 #endif /* JTAG_H */