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   1 /* SPDX-License-Identifier: GPL-2.0-or-later */
   2
   3 /***************************************************************************
   4  *   Copyright (C) 2018 by Square, Inc.                                    *
   5  *   Steven Stallion <stallion@squareup.com>                               *
   6  *   James Zhao <hjz@squareup.com>                                         *
   7  ***************************************************************************/
   8
   9 #ifdef HAVE_CONFIG_H
  10 #include "config.h"
  11 #endif
  12
  13 #include <helper/binarybuffer.h>
  14 #include <helper/log.h>
  15 #include <helper/types.h>
  16 #include <jtag/jtag.h>
  17 #include <jtag/commands.h>
  18 #include <jtag/interface.h>
  19
  20 #include "esirisc_jtag.h"
  21
  22 static void esirisc_jtag_set_instr(struct esirisc_jtag *jtag_info, uint32_t new_instr)
  23 {
  24         struct jtag_tap *tap = jtag_info->tap;
  25
  26         if (buf_get_u32(tap->cur_instr, 0, tap->ir_length) != new_instr) {
  27                 struct scan_field field;
  28                 uint8_t t[4] = { 0 };
  29
  30                 field.num_bits = tap->ir_length;
  31                 field.out_value = t;
  32                 buf_set_u32(t, 0, field.num_bits, new_instr);
  33                 field.in_value = NULL;
  34
  35                 jtag_add_ir_scan(tap, &field, TAP_IDLE);
  36         }
  37 }
  38
  39 /*
  40  * The data register is latched every 8 bits while in the Shift-DR state
  41  * (Update-DR is not supported). This necessitates prepending padding
  42  * bits to ensure data is aligned when multiple TAPs are present.
  43  */
  44 static int esirisc_jtag_get_padding(void)
  45 {
  46         int padding = 0;
  47         int bypass_devices = 0;
  48
  49         for (struct jtag_tap *tap = jtag_tap_next_enabled(NULL); tap;
  50                         tap = jtag_tap_next_enabled(tap))
  51                 if (tap->bypass)
  52                         bypass_devices++;
  53
  54         int num_bits = bypass_devices % 8;
  55         if (num_bits > 0)
  56                 padding = 8 - num_bits;
  57
  58         return padding;
  59 }
  60
  61 static int esirisc_jtag_count_bits(int num_fields, struct scan_field *fields)
  62 {
  63         int bit_count = 0;
  64
  65         for (int i = 0; i < num_fields; ++i)
  66                 bit_count += fields[i].num_bits;
  67
  68         return bit_count;
  69 }
  70
  71 /*
  72  * Data received from the target will be byte-stuffed if it contains
  73  * either the pad byte (0xAA) or stuffing marker (0x55). Buffers should
  74  * be sized twice the expected length to account for stuffing overhead.
  75  */
  76 static void esirisc_jtag_unstuff(uint8_t *data, size_t len)
  77 {
  78         uint8_t *r, *w;
  79         uint8_t *end;
  80
  81         r = w = data;
  82         end = data + len;
  83         while (r < end) {
  84                 if (*r == STUFF_MARKER) {
  85                         r++; /* skip stuffing marker */
  86                         assert(r < end);
  87                         *w++ = *r++ ^ STUFF_MARKER;
  88                 } else
  89                         *w++ = *r++;
  90         }
  91 }
  92
  93 /*
  94  * The eSi-Debug protocol defines a byte-oriented command/response
  95  * channel that operates over serial or JTAG. While not strictly
  96  * required, separate DR scans are used for sending and receiving data.
  97  * This allows the TAP to recover gracefully if the byte stream is
  98  * corrupted at the expense of sending additional padding bits.
  99  */
 100
 101 static int esirisc_jtag_send(struct esirisc_jtag *jtag_info, uint8_t command,
 102                 int num_out_fields, struct scan_field *out_fields)
 103 {
 104         int num_fields = 2 + num_out_fields;
 105         struct scan_field *fields = cmd_queue_alloc(num_fields * sizeof(struct scan_field));
 106
 107         esirisc_jtag_set_instr(jtag_info, INSTR_DEBUG);
 108
 109         fields[0].num_bits = esirisc_jtag_get_padding();
 110         fields[0].out_value = NULL;
 111         fields[0].in_value = NULL;
 112
 113         fields[1].num_bits = 8;
 114         fields[1].out_value = &command;
 115         fields[1].in_value = NULL;
 116
 117         /* append command data */
 118         for (int i = 0; i < num_out_fields; ++i)
 119                 jtag_scan_field_clone(&fields[2+i], &out_fields[i]);
 120
 121         jtag_add_dr_scan(jtag_info->tap, num_fields, fields, TAP_IDLE);
 122
 123         return jtag_execute_queue();
 124 }
 125
 126 static int esirisc_jtag_recv(struct esirisc_jtag *jtag_info,
 127                 int num_in_fields, struct scan_field *in_fields)
 128 {
 129         int num_in_bits = esirisc_jtag_count_bits(num_in_fields, in_fields);
 130         int num_in_bytes = DIV_ROUND_UP(num_in_bits, 8);
 131
 132         struct scan_field fields[3];
 133         uint8_t r[num_in_bytes * 2];
 134
 135         esirisc_jtag_set_instr(jtag_info, INSTR_DEBUG);
 136
 137         fields[0].num_bits = esirisc_jtag_get_padding() + 1;
 138         fields[0].out_value = NULL;
 139         fields[0].in_value = NULL;
 140
 141         fields[1].num_bits = 8;
 142         fields[1].out_value = NULL;
 143         fields[1].in_value = &jtag_info->status;
 144
 145         fields[2].num_bits = num_in_bits * 2;
 146         fields[2].out_value = NULL;
 147         fields[2].in_value = r;
 148
 149         jtag_add_dr_scan(jtag_info->tap, ARRAY_SIZE(fields), fields, TAP_IDLE);
 150
 151         int retval = jtag_execute_queue();
 152         if (retval != ERROR_OK)
 153                 return retval;
 154
 155         /* unstuff response data and write back to caller */
 156         if (num_in_fields > 0) {
 157                 esirisc_jtag_unstuff(r, ARRAY_SIZE(r));
 158
 159                 int bit_count = 0;
 160                 for (int i = 0; i < num_in_fields; ++i) {
 161                         buf_set_buf(r, bit_count, in_fields[i].in_value, 0, in_fields[i].num_bits);
 162                         bit_count += in_fields[i].num_bits;
 163                 }
 164         }
 165
 166         return ERROR_OK;
 167 }
 168
 169 static int esirisc_jtag_check_status(struct esirisc_jtag *jtag_info)
 170 {
 171         uint8_t eid = esirisc_jtag_get_eid(jtag_info);
 172         if (eid != EID_NONE) {
 173                 LOG_ERROR("esirisc_jtag: bad status: 0x%02" PRIx8 " (DA: %" PRId32 ", "
 174                                 "S: %" PRId32 ", EID: 0x%02" PRIx8 ")",
 175                                 jtag_info->status, esirisc_jtag_is_debug_active(jtag_info),
 176                                 esirisc_jtag_is_stopped(jtag_info), eid);
 177                 return ERROR_FAIL;
 178         }
 179
 180         return ERROR_OK;
 181 }
 182
 183 static int esirisc_jtag_send_and_recv(struct esirisc_jtag *jtag_info, uint8_t command,
 184                 int num_out_fields, struct scan_field *out_fields,
 185                 int num_in_fields, struct scan_field *in_fields)
 186 {
 187         int retval;
 188
 189         jtag_info->status = 0;  /* clear status */
 190
 191         retval = esirisc_jtag_send(jtag_info, command, num_out_fields, out_fields);
 192         if (retval != ERROR_OK) {
 193                 LOG_ERROR("esirisc_jtag: send failed (command: 0x%02" PRIx8 ")", command);
 194                 return ERROR_FAIL;
 195         }
 196
 197         retval = esirisc_jtag_recv(jtag_info, num_in_fields, in_fields);
 198         if (retval != ERROR_OK) {
 199                 LOG_ERROR("esirisc_jtag: recv failed (command: 0x%02" PRIx8 ")", command);
 200                 return ERROR_FAIL;
 201         }
 202
 203         return esirisc_jtag_check_status(jtag_info);
 204 }
 205
 206 /*
 207  * Status is automatically updated after each command completes;
 208  * these functions make each field available to the caller.
 209  */
 210
 211 bool esirisc_jtag_is_debug_active(struct esirisc_jtag *jtag_info)
 212 {
 213         return !!(jtag_info->status & 1<<7);    /* DA */
 214 }
 215
 216 bool esirisc_jtag_is_stopped(struct esirisc_jtag *jtag_info)
 217 {
 218         return !!(jtag_info->status & 1<<6);    /* S */
 219 }
 220
 221 uint8_t esirisc_jtag_get_eid(struct esirisc_jtag *jtag_info)
 222 {
 223         return jtag_info->status & 0x3f;                /* EID */
 224 }
 225
 226 /*
 227  * Most commands manipulate target data (eg. memory and registers); each
 228  * command returns a status byte that indicates success. Commands must
 229  * transmit multibyte values in big-endian order, however response
 230  * values are in little-endian order. Target endianness does not have an
 231  * effect on this ordering.
 232  */
 233
 234 int esirisc_jtag_read_byte(struct esirisc_jtag *jtag_info, uint32_t address, uint8_t *data)
 235 {
 236         struct scan_field out_fields[1];
 237         uint8_t a[4];
 238
 239         out_fields[0].num_bits = 32;
 240         out_fields[0].out_value = a;
 241         h_u32_to_be(a, address);
 242         out_fields[0].in_value = NULL;
 243
 244         struct scan_field in_fields[1];
 245         uint8_t d[1];
 246
 247         in_fields[0].num_bits = 8;
 248         in_fields[0].out_value = NULL;
 249         in_fields[0].in_value = d;
 250
 251         int retval = esirisc_jtag_send_and_recv(jtag_info, DEBUG_READ_BYTE,
 252                         ARRAY_SIZE(out_fields), out_fields, ARRAY_SIZE(in_fields), in_fields);
 253         if (retval != ERROR_OK)
 254                 return retval;
 255
 256         *data = *d;
 257         LOG_DEBUG("address: 0x%" PRIx32 ", data: 0x%" PRIx8, address, *data);
 258
 259         return ERROR_OK;
 260 }
 261
 262 int esirisc_jtag_read_hword(struct esirisc_jtag *jtag_info, uint32_t address, uint16_t *data)
 263 {
 264         struct scan_field out_fields[1];
 265         uint8_t a[4];
 266
 267         out_fields[0].num_bits = 32;
 268         out_fields[0].out_value = a;
 269         h_u32_to_be(a, address);
 270         out_fields[0].in_value = NULL;
 271
 272         struct scan_field in_fields[1];
 273         uint8_t d[2];
 274
 275         in_fields[0].num_bits = 16;
 276         in_fields[0].out_value = NULL;
 277         in_fields[0].in_value = d;
 278
 279         int retval = esirisc_jtag_send_and_recv(jtag_info, DEBUG_READ_HWORD,
 280                         ARRAY_SIZE(out_fields), out_fields, ARRAY_SIZE(in_fields), in_fields);
 281         if (retval != ERROR_OK)
 282                 return retval;
 283
 284         *data = le_to_h_u16(d);
 285         LOG_DEBUG("address: 0x%" PRIx32 ", data: 0x%" PRIx16, address, *data);
 286
 287         return ERROR_OK;
 288 }
 289
 290 int esirisc_jtag_read_word(struct esirisc_jtag *jtag_info, uint32_t address, uint32_t *data)
 291 {
 292         struct scan_field out_fields[1];
 293         uint8_t a[4];
 294
 295         out_fields[0].num_bits = 32;
 296         out_fields[0].out_value = a;
 297         h_u32_to_be(a, address);
 298         out_fields[0].in_value = NULL;
 299
 300         struct scan_field in_fields[1];
 301         uint8_t d[4];
 302
 303         in_fields[0].num_bits = 32;
 304         in_fields[0].out_value = NULL;
 305         in_fields[0].in_value = d;
 306
 307         int retval = esirisc_jtag_send_and_recv(jtag_info, DEBUG_READ_WORD,
 308                         ARRAY_SIZE(out_fields), out_fields, ARRAY_SIZE(in_fields), in_fields);
 309         if (retval != ERROR_OK)
 310                 return retval;
 311
 312         *data = le_to_h_u32(d);
 313         LOG_DEBUG("address: 0x%" PRIx32 ", data: 0x%" PRIx32, address, *data);
 314
 315         return ERROR_OK;
 316 }
 317
 318 int esirisc_jtag_write_byte(struct esirisc_jtag *jtag_info, uint32_t address, uint8_t data)
 319 {
 320         struct scan_field out_fields[2];
 321         uint8_t a[4];
 322
 323         LOG_DEBUG("address: 0x%" PRIx32 ", data: 0x%" PRIx8, address, data);
 324
 325         out_fields[0].num_bits = 32;
 326         out_fields[0].out_value = a;
 327         h_u32_to_be(a, address);
 328         out_fields[0].in_value = NULL;
 329
 330         out_fields[1].num_bits = 8;
 331         out_fields[1].out_value = &data;
 332         out_fields[1].in_value = NULL;
 333
 334         return esirisc_jtag_send_and_recv(jtag_info, DEBUG_WRITE_BYTE,
 335                         ARRAY_SIZE(out_fields), out_fields, 0, NULL);
 336 }
 337
 338 int esirisc_jtag_write_hword(struct esirisc_jtag *jtag_info, uint32_t address, uint16_t data)
 339 {
 340         struct scan_field out_fields[2];
 341         uint8_t a[4], d[2];
 342
 343         LOG_DEBUG("address: 0x%" PRIx32 ", data: 0x%" PRIx16, address, data);
 344
 345         out_fields[0].num_bits = 32;
 346         out_fields[0].out_value = a;
 347         h_u32_to_be(a, address);
 348         out_fields[0].in_value = NULL;
 349
 350         out_fields[1].num_bits = 16;
 351         out_fields[1].out_value = d;
 352         h_u16_to_be(d, data);
 353         out_fields[1].in_value = NULL;
 354
 355         return esirisc_jtag_send_and_recv(jtag_info, DEBUG_WRITE_HWORD,
 356                         ARRAY_SIZE(out_fields), out_fields, 0, NULL);
 357 }
 358
 359 int esirisc_jtag_write_word(struct esirisc_jtag *jtag_info, uint32_t address, uint32_t data)
 360 {
 361         struct scan_field out_fields[2];
 362         uint8_t a[4], d[4];
 363
 364         LOG_DEBUG("address: 0x%" PRIx32 ", data: 0x%" PRIx32, address, data);
 365
 366         out_fields[0].num_bits = 32;
 367         out_fields[0].out_value = a;
 368         h_u32_to_be(a, address);
 369         out_fields[0].in_value = NULL;
 370
 371         out_fields[1].num_bits = 32;
 372         out_fields[1].out_value = d;
 373         h_u32_to_be(d, data);
 374         out_fields[1].in_value = NULL;
 375
 376         return esirisc_jtag_send_and_recv(jtag_info, DEBUG_WRITE_WORD,
 377                         ARRAY_SIZE(out_fields), out_fields, 0, NULL);
 378 }
 379
 380 int esirisc_jtag_read_reg(struct esirisc_jtag *jtag_info, uint8_t reg, uint32_t *data)
 381 {
 382         struct scan_field out_fields[1];
 383
 384         out_fields[0].num_bits = 8;
 385         out_fields[0].out_value = &reg;
 386         out_fields[0].in_value = NULL;
 387
 388         struct scan_field in_fields[1];
 389         uint8_t d[4];
 390
 391         in_fields[0].num_bits = 32;
 392         in_fields[0].out_value = NULL;
 393         in_fields[0].in_value = d;
 394
 395         int retval = esirisc_jtag_send_and_recv(jtag_info, DEBUG_READ_REG,
 396                         ARRAY_SIZE(out_fields), out_fields, ARRAY_SIZE(in_fields), in_fields);
 397         if (retval != ERROR_OK)
 398                 return retval;
 399
 400         *data = le_to_h_u32(d);
 401         LOG_DEBUG("register: 0x%" PRIx8 ", data: 0x%" PRIx32, reg, *data);
 402
 403         return ERROR_OK;
 404 }
 405
 406 int esirisc_jtag_write_reg(struct esirisc_jtag *jtag_info, uint8_t reg, uint32_t data)
 407 {
 408         struct scan_field out_fields[2];
 409         uint8_t d[4];
 410
 411         LOG_DEBUG("register: 0x%" PRIx8 ", data: 0x%" PRIx32, reg, data);
 412
 413         out_fields[0].num_bits = 8;
 414         out_fields[0].out_value = &reg;
 415         out_fields[0].in_value = NULL;
 416
 417         out_fields[1].num_bits = 32;
 418         out_fields[1].out_value = d;
 419         h_u32_to_be(d, data);
 420         out_fields[1].in_value = NULL;
 421
 422         return esirisc_jtag_send_and_recv(jtag_info, DEBUG_WRITE_REG,
 423                         ARRAY_SIZE(out_fields), out_fields, 0, NULL);
 424 }
 425
 426 int esirisc_jtag_read_csr(struct esirisc_jtag *jtag_info, uint8_t bank, uint8_t csr, uint32_t *data)
 427 {
 428         struct scan_field out_fields[1];
 429         uint8_t c[2];
 430
 431         out_fields[0].num_bits = 16;
 432         out_fields[0].out_value = c;
 433         h_u16_to_be(c, (csr << 5) | bank);
 434         out_fields[0].in_value = NULL;
 435
 436         struct scan_field in_fields[1];
 437         uint8_t d[4];
 438
 439         in_fields[0].num_bits = 32;
 440         in_fields[0].out_value = NULL;
 441         in_fields[0].in_value = d;
 442
 443         int retval = esirisc_jtag_send_and_recv(jtag_info, DEBUG_READ_CSR,
 444                         ARRAY_SIZE(out_fields), out_fields, ARRAY_SIZE(in_fields), in_fields);
 445         if (retval != ERROR_OK)
 446                 return retval;
 447
 448         *data = le_to_h_u32(d);
 449         LOG_DEBUG("bank: 0x%" PRIx8 ", csr: 0x%" PRIx8 ", data: 0x%" PRIx32, bank, csr, *data);
 450
 451         return ERROR_OK;
 452 }
 453
 454 int esirisc_jtag_write_csr(struct esirisc_jtag *jtag_info, uint8_t bank, uint8_t csr, uint32_t data)
 455 {
 456         struct scan_field out_fields[2];
 457         uint8_t c[2], d[4];
 458
 459         LOG_DEBUG("bank: 0x%" PRIx8 ", csr: 0x%" PRIx8 ", data: 0x%" PRIx32, bank, csr, data);
 460
 461         out_fields[0].num_bits = 16;
 462         out_fields[0].out_value = c;
 463         h_u16_to_be(c, (csr << 5) | bank);
 464         out_fields[0].in_value = NULL;
 465
 466         out_fields[1].num_bits = 32;
 467         out_fields[1].out_value = d;
 468         h_u32_to_be(d, data);
 469         out_fields[1].in_value = NULL;
 470
 471         return esirisc_jtag_send_and_recv(jtag_info, DEBUG_WRITE_CSR,
 472                         ARRAY_SIZE(out_fields), out_fields, 0, NULL);
 473 }
 474
 475 /*
 476  * Control commands affect CPU operation; these commands send no data
 477  * and return a status byte.
 478  */
 479
 480 static inline int esirisc_jtag_send_ctrl(struct esirisc_jtag *jtag_info, uint8_t command)
 481 {
 482         return esirisc_jtag_send_and_recv(jtag_info, command, 0, NULL, 0, NULL);
 483 }
 484
 485 int esirisc_jtag_enable_debug(struct esirisc_jtag *jtag_info)
 486 {
 487         return esirisc_jtag_send_ctrl(jtag_info, DEBUG_ENABLE_DEBUG);
 488 }
 489
 490 int esirisc_jtag_disable_debug(struct esirisc_jtag *jtag_info)
 491 {
 492         return esirisc_jtag_send_ctrl(jtag_info, DEBUG_DISABLE_DEBUG);
 493 }
 494
 495 int esirisc_jtag_assert_reset(struct esirisc_jtag *jtag_info)
 496 {
 497         return esirisc_jtag_send_ctrl(jtag_info, DEBUG_ASSERT_RESET);
 498 }
 499
 500 int esirisc_jtag_deassert_reset(struct esirisc_jtag *jtag_info)
 501 {
 502         return esirisc_jtag_send_ctrl(jtag_info, DEBUG_DEASSERT_RESET);
 503 }
 504
 505 int esirisc_jtag_break(struct esirisc_jtag *jtag_info)
 506 {
 507         return esirisc_jtag_send_ctrl(jtag_info, DEBUG_BREAK);
 508 }
 509
 510 int esirisc_jtag_continue(struct esirisc_jtag *jtag_info)
 511 {
 512         return esirisc_jtag_send_ctrl(jtag_info, DEBUG_CONTINUE);
 513 }
 514
 515 int esirisc_jtag_flush_caches(struct esirisc_jtag *jtag_info)
 516 {
 517         return esirisc_jtag_send_ctrl(jtag_info, DEBUG_FLUSH_CACHES);
 518 }