Remove BUILD_TARGET64
[fw/openocd] / src / target / mips_ejtag.c
1 /***************************************************************************
2  *   Copyright (C) 2008 by Spencer Oliver                                  *
3  *   spen@spen-soft.co.uk                                                  *
4  *                                                                         *
5  *   Copyright (C) 2008 by David T.L. Wong                                 *
6  *                                                                         *
7  *   Copyright (C) 2009 by David N. Claffey <dnclaffey@gmail.com>          *
8  *                                                                         *
9  *   This program is free software; you can redistribute it and/or modify  *
10  *   it under the terms of the GNU General Public License as published by  *
11  *   the Free Software Foundation; either version 2 of the License, or     *
12  *   (at your option) any later version.                                   *
13  *                                                                         *
14  *   This program is distributed in the hope that it will be useful,       *
15  *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
16  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
17  *   GNU General Public License for more details.                          *
18  *                                                                         *
19  *   You should have received a copy of the GNU General Public License     *
20  *   along with this program.  If not, see <http://www.gnu.org/licenses/>. *
21  ***************************************************************************/
22
23 #ifdef HAVE_CONFIG_H
24 #include "config.h"
25 #endif
26
27 #include "mips32.h"
28 #include "mips_ejtag.h"
29 #include "mips32_dmaacc.h"
30 #include "mips64.h"
31 #include "mips64_pracc.h"
32
33 void mips_ejtag_set_instr(struct mips_ejtag *ejtag_info, uint32_t new_instr)
34 {
35         assert(ejtag_info->tap != NULL);
36         struct jtag_tap *tap = ejtag_info->tap;
37
38         if (buf_get_u32(tap->cur_instr, 0, tap->ir_length) != new_instr) {
39
40                 struct scan_field field;
41                 field.num_bits = tap->ir_length;
42
43                 uint8_t t[4] = { 0 };
44                 field.out_value = t;
45                 buf_set_u32(t, 0, field.num_bits, new_instr);
46
47                 field.in_value = NULL;
48
49                 jtag_add_ir_scan(tap, &field, TAP_IDLE);
50         }
51 }
52
53 int mips_ejtag_get_idcode(struct mips_ejtag *ejtag_info)
54 {
55         mips_ejtag_set_instr(ejtag_info, EJTAG_INST_IDCODE);
56
57         ejtag_info->idcode = 0;
58         return mips_ejtag_drscan_32(ejtag_info, &ejtag_info->idcode);
59 }
60
61 int mips_ejtag_get_impcode(struct mips_ejtag *ejtag_info)
62 {
63         mips_ejtag_set_instr(ejtag_info, EJTAG_INST_IMPCODE);
64
65         ejtag_info->impcode = 0;
66         return mips_ejtag_drscan_32(ejtag_info, &ejtag_info->impcode);
67 }
68
69 void mips_ejtag_add_scan_96(struct mips_ejtag *ejtag_info, uint32_t ctrl, uint32_t data, uint8_t *in_scan_buf)
70 {
71         assert(ejtag_info->tap != NULL);
72         struct jtag_tap *tap = ejtag_info->tap;
73
74         struct scan_field field;
75         uint8_t out_scan[12];
76
77         /* processor access "all" register 96 bit */
78         field.num_bits = 96;
79
80         field.out_value = out_scan;
81         buf_set_u32(out_scan, 0, 32, ctrl);
82         buf_set_u32(out_scan + 4, 0, 32, data);
83         buf_set_u32(out_scan + 8, 0, 32, 0);
84
85         field.in_value = in_scan_buf;
86
87         jtag_add_dr_scan(tap, 1, &field, TAP_IDLE);
88
89         keep_alive();
90 }
91
92 int mips_ejtag_drscan_64(struct mips_ejtag *ejtag_info, uint64_t *data)
93 {
94         struct jtag_tap *tap;
95         tap  = ejtag_info->tap;
96
97         if (tap == NULL)
98                 return ERROR_FAIL;
99         struct scan_field field;
100         uint8_t t[8] = { 0 }, r[8];
101         int retval;
102
103         field.num_bits = 64;
104         field.out_value = t;
105         buf_set_u64(t, 0, field.num_bits, *data);
106         field.in_value = r;
107
108         jtag_add_dr_scan(tap, 1, &field, TAP_IDLE);
109         retval = jtag_execute_queue();
110         if (retval != ERROR_OK) {
111                 LOG_ERROR("register read failed");
112                 return retval;
113         }
114
115         *data = buf_get_u64(field.in_value, 0, 64);
116
117         keep_alive();
118
119         return ERROR_OK;
120 }
121
122 void mips_ejtag_drscan_32_queued(struct mips_ejtag *ejtag_info, uint32_t data_out, uint8_t *data_in)
123 {
124         assert(ejtag_info->tap != NULL);
125         struct jtag_tap *tap = ejtag_info->tap;
126
127         struct scan_field field;
128         field.num_bits = 32;
129
130         uint8_t scan_out[4] = { 0 };
131         field.out_value = scan_out;
132         buf_set_u32(scan_out, 0, field.num_bits, data_out);
133
134         field.in_value = data_in;
135         jtag_add_dr_scan(tap, 1, &field, TAP_IDLE);
136
137         keep_alive();
138 }
139
140 int mips_ejtag_drscan_32(struct mips_ejtag *ejtag_info, uint32_t *data)
141 {
142         uint8_t scan_in[4];
143         mips_ejtag_drscan_32_queued(ejtag_info, *data, scan_in);
144
145         int retval = jtag_execute_queue();
146         if (retval != ERROR_OK) {
147                 LOG_ERROR("register read failed");
148                 return retval;
149         }
150
151         *data = buf_get_u32(scan_in, 0, 32);
152         return ERROR_OK;
153 }
154
155 void mips_ejtag_drscan_32_out(struct mips_ejtag *ejtag_info, uint32_t data)
156 {
157         mips_ejtag_drscan_32_queued(ejtag_info, data, NULL);
158 }
159
160 int mips_ejtag_drscan_8(struct mips_ejtag *ejtag_info, uint8_t *data)
161 {
162         assert(ejtag_info->tap != NULL);
163         struct jtag_tap *tap = ejtag_info->tap;
164
165         struct scan_field field;
166         field.num_bits = 8;
167
168         field.out_value = data;
169         field.in_value = data;
170
171         jtag_add_dr_scan(tap, 1, &field, TAP_IDLE);
172
173         int retval = jtag_execute_queue();
174         if (retval != ERROR_OK) {
175                 LOG_ERROR("register read failed");
176                 return retval;
177         }
178         return ERROR_OK;
179 }
180
181 void mips_ejtag_drscan_8_out(struct mips_ejtag *ejtag_info, uint8_t data)
182 {
183         assert(ejtag_info->tap != NULL);
184         struct jtag_tap *tap = ejtag_info->tap;
185
186         struct scan_field field;
187         field.num_bits = 8;
188
189         field.out_value = &data;
190         field.in_value = NULL;
191
192         jtag_add_dr_scan(tap, 1, &field, TAP_IDLE);
193 }
194
195 /* Set (to enable) or clear (to disable stepping) the SSt bit (bit 8) in Cp0 Debug reg (reg 23, sel 0) */
196 int mips_ejtag_config_step(struct mips_ejtag *ejtag_info, int enable_step)
197 {
198         struct pracc_queue_info ctx = {.ejtag_info = ejtag_info};
199         pracc_queue_init(&ctx);
200
201         pracc_add(&ctx, 0, MIPS32_MFC0(ctx.isa, 8, 23, 0));                     /* move COP0 Debug to $8 */
202         pracc_add(&ctx, 0, MIPS32_ORI(ctx.isa, 8, 8, 0x0100));                  /* set SSt bit in debug reg */
203         if (!enable_step)
204                 pracc_add(&ctx, 0, MIPS32_XORI(ctx.isa, 8, 8, 0x0100));         /* clear SSt bit in debug reg */
205
206         pracc_add(&ctx, 0, MIPS32_MTC0(ctx.isa, 8, 23, 0));                     /* move $8 to COP0 Debug */
207         pracc_add(&ctx, 0, MIPS32_LUI(ctx.isa, 8, UPPER16(ejtag_info->reg8)));  /* restore upper 16 bits  of $8 */
208         pracc_add(&ctx, 0, MIPS32_B(ctx.isa, NEG16((ctx.code_count + 1) << ctx.isa)));          /* jump to start */
209         pracc_add(&ctx, 0, MIPS32_ORI(ctx.isa, 8, 8, LOWER16(ejtag_info->reg8))); /* restore lower 16 bits of $8 */
210
211         ctx.retval = mips32_pracc_queue_exec(ejtag_info, &ctx, NULL, 1);
212         pracc_queue_free(&ctx);
213         return ctx.retval;
214 }
215
216 /*
217  * Disable memory protection for 0xFF20.0000–0xFF3F.FFFF
218  * It is needed by EJTAG 1.5-2.0, especially for BMIPS CPUs
219  * For example bcm7401 and others. At leas on some
220  * CPUs, DebugMode wont start if this bit is not removed.
221  */
222 static int disable_dcr_mp(struct mips_ejtag *ejtag_info)
223 {
224         uint32_t dcr;
225         int retval;
226
227         retval = mips32_dmaacc_read_mem(ejtag_info, EJTAG_DCR, 4, 1, &dcr);
228         if (retval != ERROR_OK)
229                 goto error;
230
231         dcr &= ~EJTAG_DCR_MP;
232         retval = mips32_dmaacc_write_mem(ejtag_info, EJTAG_DCR, 4, 1, &dcr);
233         if (retval != ERROR_OK)
234                 goto error;
235         return ERROR_OK;
236 error:
237         LOG_ERROR("Failed to remove DCR MPbit!");
238         return retval;
239 }
240
241 int mips_ejtag_enter_debug(struct mips_ejtag *ejtag_info)
242 {
243         uint32_t ejtag_ctrl;
244         mips_ejtag_set_instr(ejtag_info, EJTAG_INST_CONTROL);
245
246         if (ejtag_info->ejtag_version == EJTAG_VERSION_20) {
247                 if (disable_dcr_mp(ejtag_info) != ERROR_OK)
248                         goto error;
249         }
250
251         /* set debug break bit */
252         ejtag_ctrl = ejtag_info->ejtag_ctrl | EJTAG_CTRL_JTAGBRK;
253         mips_ejtag_drscan_32(ejtag_info, &ejtag_ctrl);
254
255         /* break bit will be cleared by hardware */
256         ejtag_ctrl = ejtag_info->ejtag_ctrl;
257         mips_ejtag_drscan_32(ejtag_info, &ejtag_ctrl);
258         LOG_DEBUG("ejtag_ctrl: 0x%8.8" PRIx32 "", ejtag_ctrl);
259         if ((ejtag_ctrl & EJTAG_CTRL_BRKST) == 0)
260                 goto error;
261
262         return ERROR_OK;
263 error:
264         LOG_ERROR("Failed to enter Debug Mode!");
265         return ERROR_FAIL;
266 }
267
268 int mips_ejtag_exit_debug(struct mips_ejtag *ejtag_info)
269 {
270         pa_list pracc_list = {.instr = MIPS32_DRET(ejtag_info->isa), .addr = 0};
271         struct pracc_queue_info ctx = {.max_code = 1, .pracc_list = &pracc_list, .code_count = 1, .store_count = 0};
272
273         /* execute our dret instruction */
274         ctx.retval = mips32_pracc_queue_exec(ejtag_info, &ctx, NULL, 0); /* shift out instr, omit last check */
275
276         /* pic32mx workaround, false pending at low core clock */
277         jtag_add_sleep(1000);
278         return ctx.retval;
279 }
280
281 /* mips_ejtag_init_mmr - asign Memory-Mapped Registers depending
282  *                      on EJTAG version.
283  */
284 static void mips_ejtag_init_mmr(struct mips_ejtag *ejtag_info)
285 {
286         if (ejtag_info->ejtag_version == EJTAG_VERSION_20) {
287                 ejtag_info->ejtag_ibs_addr      = EJTAG_V20_IBS;
288                 ejtag_info->ejtag_iba0_addr     = EJTAG_V20_IBA0;
289                 ejtag_info->ejtag_ibc_offs      = EJTAG_V20_IBC_OFFS;
290                 ejtag_info->ejtag_ibm_offs      = EJTAG_V20_IBM_OFFS;
291
292                 ejtag_info->ejtag_dbs_addr      = EJTAG_V20_DBS;
293                 ejtag_info->ejtag_dba0_addr     = EJTAG_V20_DBA0;
294                 ejtag_info->ejtag_dbc_offs      = EJTAG_V20_DBC_OFFS;
295                 ejtag_info->ejtag_dbm_offs      = EJTAG_V20_DBM_OFFS;
296                 ejtag_info->ejtag_dbv_offs      = EJTAG_V20_DBV_OFFS;
297
298                 ejtag_info->ejtag_iba_step_size = EJTAG_V20_IBAn_STEP;
299                 ejtag_info->ejtag_dba_step_size = EJTAG_V20_DBAn_STEP;
300         } else {
301                 ejtag_info->ejtag_ibs_addr      = EJTAG_V25_IBS;
302                 ejtag_info->ejtag_iba0_addr     = EJTAG_V25_IBA0;
303                 ejtag_info->ejtag_ibm_offs      = EJTAG_V25_IBM_OFFS;
304                 ejtag_info->ejtag_ibasid_offs   = EJTAG_V25_IBASID_OFFS;
305                 ejtag_info->ejtag_ibc_offs      = EJTAG_V25_IBC_OFFS;
306
307                 ejtag_info->ejtag_dbs_addr      = EJTAG_V25_DBS;
308                 ejtag_info->ejtag_dba0_addr     = EJTAG_V25_DBA0;
309                 ejtag_info->ejtag_dbm_offs      = EJTAG_V25_DBM_OFFS;
310                 ejtag_info->ejtag_dbasid_offs   = EJTAG_V25_DBASID_OFFS;
311                 ejtag_info->ejtag_dbc_offs      = EJTAG_V25_DBC_OFFS;
312                 ejtag_info->ejtag_dbv_offs      = EJTAG_V25_DBV_OFFS;
313
314                 ejtag_info->ejtag_iba_step_size = EJTAG_V25_IBAn_STEP;
315                 ejtag_info->ejtag_dba_step_size = EJTAG_V25_DBAn_STEP;
316         }
317 }
318
319 static void ejtag_v20_print_imp(struct mips_ejtag *ejtag_info)
320 {
321         LOG_DEBUG("EJTAG v2.0: features:%s%s%s%s%s%s%s%s",
322                 EJTAG_IMP_HAS(EJTAG_V20_IMP_SDBBP) ? " SDBBP_SPECIAL2" : " SDBBP",
323                 EJTAG_IMP_HAS(EJTAG_V20_IMP_EADDR_NO32BIT) ? " EADDR>32bit" : " EADDR=32bit",
324                 EJTAG_IMP_HAS(EJTAG_V20_IMP_COMPLEX_BREAK) ? " COMPLEX_BREAK" : "",
325                 EJTAG_IMP_HAS(EJTAG_V20_IMP_DCACHE_COH) ? " DCACHE_COH" : " DCACHE_NOT_COH",
326                 EJTAG_IMP_HAS(EJTAG_V20_IMP_ICACHE_COH) ? " ICACHE_COH" : " ICACHE_NOT_COH",
327                 EJTAG_IMP_HAS(EJTAG_V20_IMP_NOPB) ? " noPB" : " PB",
328                 EJTAG_IMP_HAS(EJTAG_V20_IMP_NODB) ? " noDB" : " DB",
329                 EJTAG_IMP_HAS(EJTAG_V20_IMP_NOIB) ? " noIB" : " IB");
330         LOG_DEBUG("EJTAG v2.0: Break Channels: %" PRIu8,
331                 (uint8_t)((ejtag_info->impcode >> EJTAG_V20_IMP_BCHANNELS_SHIFT) &
332                 EJTAG_V20_IMP_BCHANNELS_MASK));
333 }
334
335 static void ejtag_v26_print_imp(struct mips_ejtag *ejtag_info)
336 {
337         LOG_DEBUG("EJTAG v2.6: features:%s%s",
338                 EJTAG_IMP_HAS(EJTAG_V26_IMP_R3K) ? " R3k" : " R4k",
339                 EJTAG_IMP_HAS(EJTAG_V26_IMP_DINT) ? " DINT" : "");
340 }
341
342 static void ejtag_main_print_imp(struct mips_ejtag *ejtag_info)
343 {
344         LOG_DEBUG("EJTAG main: features:%s%s%s%s%s",
345                 EJTAG_IMP_HAS(EJTAG_IMP_ASID8) ? " ASID_8" : "",
346                 EJTAG_IMP_HAS(EJTAG_IMP_ASID6) ? " ASID_6" : "",
347                 EJTAG_IMP_HAS(EJTAG_IMP_MIPS16) ? " MIPS16" : "",
348                 EJTAG_IMP_HAS(EJTAG_IMP_NODMA) ? " noDMA" : " DMA",
349                 EJTAG_IMP_HAS(EJTAG_IMP_MIPS64) ? " MIPS64" : " MIPS32");
350
351         switch (ejtag_info->ejtag_version) {
352                 case EJTAG_VERSION_20:
353                         ejtag_v20_print_imp(ejtag_info);
354                         break;
355                 case EJTAG_VERSION_25:
356                 case EJTAG_VERSION_26:
357                 case EJTAG_VERSION_31:
358                 case EJTAG_VERSION_41:
359                 case EJTAG_VERSION_51:
360                         ejtag_v26_print_imp(ejtag_info);
361                         break;
362                 default:
363                         break;
364         }
365 }
366
367 int mips_ejtag_init(struct mips_ejtag *ejtag_info)
368 {
369         int retval = mips_ejtag_get_impcode(ejtag_info);
370         if (retval != ERROR_OK) {
371                 LOG_ERROR("impcode read failed");
372                 return retval;
373         }
374
375         /* get ejtag version */
376         ejtag_info->ejtag_version = ((ejtag_info->impcode >> 29) & 0x07);
377
378         switch (ejtag_info->ejtag_version) {
379                 case EJTAG_VERSION_20:
380                         LOG_DEBUG("EJTAG: Version 1 or 2.0 Detected");
381                         break;
382                 case EJTAG_VERSION_25:
383                         LOG_DEBUG("EJTAG: Version 2.5 Detected");
384                         break;
385                 case EJTAG_VERSION_26:
386                         LOG_DEBUG("EJTAG: Version 2.6 Detected");
387                         break;
388                 case EJTAG_VERSION_31:
389                         LOG_DEBUG("EJTAG: Version 3.1 Detected");
390                         break;
391                 case EJTAG_VERSION_41:
392                         LOG_DEBUG("EJTAG: Version 4.1 Detected");
393                         break;
394                 case EJTAG_VERSION_51:
395                         LOG_DEBUG("EJTAG: Version 5.1 Detected");
396                         break;
397                 default:
398                         LOG_DEBUG("EJTAG: Unknown Version Detected");
399                         break;
400         }
401         ejtag_main_print_imp(ejtag_info);
402
403         if ((ejtag_info->impcode & EJTAG_IMP_NODMA) == 0) {
404                 LOG_DEBUG("EJTAG: DMA Access Mode detected. Disabling to "
405                           "workaround current broken code.");
406                 ejtag_info->impcode |= EJTAG_IMP_NODMA;
407         }
408
409         ejtag_info->ejtag_ctrl = EJTAG_CTRL_PRACC | EJTAG_CTRL_PROBEN;
410
411         if (ejtag_info->ejtag_version != EJTAG_VERSION_20)
412                 ejtag_info->ejtag_ctrl |= EJTAG_CTRL_ROCC | EJTAG_CTRL_SETDEV;
413
414         ejtag_info->fast_access_save = -1;
415
416         mips_ejtag_init_mmr(ejtag_info);
417
418         return ERROR_OK;
419 }
420
421 int mips_ejtag_fastdata_scan(struct mips_ejtag *ejtag_info, int write_t, uint32_t *data)
422 {
423         assert(ejtag_info->tap != NULL);
424         struct jtag_tap *tap = ejtag_info->tap;
425
426         struct scan_field fields[2];
427
428         /* fastdata 1-bit register */
429         fields[0].num_bits = 1;
430
431         uint8_t spracc = 0;
432         fields[0].out_value = &spracc;
433         fields[0].in_value = NULL;
434
435         /* processor access data register 32 bit */
436         fields[1].num_bits = 32;
437
438         uint8_t t[4] = {0, 0, 0, 0};
439         fields[1].out_value = t;
440
441         if (write_t) {
442                 fields[1].in_value = NULL;
443                 buf_set_u32(t, 0, 32, *data);
444         } else
445                 fields[1].in_value = (uint8_t *) data;
446
447         jtag_add_dr_scan(tap, 2, fields, TAP_IDLE);
448
449         if (!write_t && data)
450                 jtag_add_callback(mips_le_to_h_u32,
451                         (jtag_callback_data_t) data);
452
453         keep_alive();
454
455         return ERROR_OK;
456 }
457
458 int mips64_ejtag_config_step(struct mips_ejtag *ejtag_info, bool enable_step)
459 {
460         const uint32_t code_enable[] = {
461                 MIPS64_MTC0(1, 31, 0),              /* move $1 to COP0 DeSave */
462                 MIPS64_MFC0(1, 23, 0),              /* move COP0 Debug to $1 */
463                 MIPS64_ORI(1, 1, 0x0100),                /* set SSt bit in debug reg */
464                 MIPS64_MTC0(1, 23, 0),              /* move $1 to COP0 Debug */
465                 MIPS64_B(NEG16(5)),
466                 MIPS64_MFC0(1, 31, 0),              /* move COP0 DeSave to $1 */
467                 MIPS64_NOP,
468                 MIPS64_NOP,
469                 MIPS64_NOP,
470                 MIPS64_NOP,
471                 MIPS64_NOP,
472                 MIPS64_NOP,
473                 MIPS64_NOP,
474                 MIPS64_NOP,
475         };
476
477         const uint32_t code_disable[] = {
478                 MIPS64_MTC0(15, 31, 0),                           /* move $15 to COP0 DeSave */
479                 MIPS64_LUI(15, UPPER16(MIPS64_PRACC_STACK)),     /* $15 = MIPS64_PRACC_STACK */
480                 MIPS64_ORI(15, 15, LOWER16(MIPS64_PRACC_STACK)),
481                 MIPS64_SD(1, 0, 15),                              /* sw $1,($15) */
482                 MIPS64_SD(2, 0, 15),                              /* sw $2,($15) */
483                 MIPS64_MFC0(1, 23, 0),                            /* move COP0 Debug to $1 */
484                 MIPS64_LUI(2, 0xFFFF),                           /* $2 = 0xfffffeff */
485                 MIPS64_ORI(2, 2, 0xFEFF),
486                 MIPS64_AND(1, 1, 2),
487                 MIPS64_MTC0(1, 23, 0),                            /* move $1 to COP0 Debug */
488                 MIPS64_LD(2, 0, 15),
489                 MIPS64_LD(1, 0, 15),
490                 MIPS64_SYNC,
491                 MIPS64_B(NEG16(14)),
492                 MIPS64_MFC0(15, 31, 0),                           /* move COP0 DeSave to $15 */
493                 MIPS64_NOP,
494                 MIPS64_NOP,
495                 MIPS64_NOP,
496                 MIPS64_NOP,
497                 MIPS64_NOP,
498                 MIPS64_NOP,
499                 MIPS64_NOP,
500                 MIPS64_NOP,
501         };
502         const uint32_t *code = enable_step ? code_enable : code_disable;
503         unsigned code_len = enable_step ? ARRAY_SIZE(code_enable) :
504                                           ARRAY_SIZE(code_disable);
505
506         return mips64_pracc_exec(ejtag_info,
507                                  code_len, code, 0, NULL, 0, NULL);
508 }
509
510 int mips64_ejtag_exit_debug(struct mips_ejtag *ejtag_info)
511 {
512         const uint32_t code[] = {
513                 MIPS64_DRET,
514                 MIPS64_NOP,
515                 MIPS64_NOP,
516                 MIPS64_NOP,
517                 MIPS64_NOP,
518                 MIPS64_NOP,
519                 MIPS64_NOP,
520                 MIPS64_NOP,
521         };
522         LOG_DEBUG("enter mips64_pracc_exec");
523         return mips64_pracc_exec(ejtag_info,
524                                  ARRAY_SIZE(code), code, 0, NULL, 0, NULL);
525 }
526
527 int mips64_ejtag_fastdata_scan(struct mips_ejtag *ejtag_info, bool write_t, uint64_t *data)
528 {
529         struct jtag_tap *tap;
530
531         tap = ejtag_info->tap;
532         assert(tap != NULL);
533
534         struct scan_field fields[2];
535         uint8_t spracc = 0;
536         uint8_t t[8] = {0, 0, 0, 0, 0, 0, 0, 0};
537
538         /* fastdata 1-bit register */
539         fields[0].num_bits = 1;
540         fields[0].out_value = &spracc;
541         fields[0].in_value = NULL;
542
543         /* processor access data register 64 bit */
544         fields[1].num_bits = 64;
545         fields[1].out_value = t;
546
547         if (write_t) {
548                 fields[1].in_value = NULL;
549                 buf_set_u64(t, 0, 64, *data);
550         } else
551                 fields[1].in_value = (uint8_t *) data;
552
553         jtag_add_dr_scan(tap, 2, fields, TAP_IDLE);
554
555         if (!write_t && data)
556                 jtag_add_callback(mips_le_to_h_u64,
557                         (jtag_callback_data_t) data);
558         keep_alive();
559
560         return ERROR_OK;
561 }