drivers/fsi/fsi-core.c

   1 /*
   2  * FSI core driver
   3  *
   4  * Copyright (C) IBM Corporation 2016
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 as
   8  * published by the Free Software Foundation.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  */
  15
  16 #include <linux/crc4.h>
  17 #include <linux/device.h>
  18 #include <linux/fsi.h>
  19 #include <linux/idr.h>
  20 #include <linux/module.h>
  21 #include <linux/slab.h>
  22 #include <linux/bitops.h>
  23
  24 #include "fsi-master.h"
  25
  26 #define CREATE_TRACE_POINTS
  27 #include <trace/events/fsi.h>
  28
  29 #define FSI_SLAVE_CONF_NEXT_MASK        GENMASK(31, 31)
  30 #define FSI_SLAVE_CONF_SLOTS_MASK       GENMASK(23, 16)
  31 #define FSI_SLAVE_CONF_SLOTS_SHIFT      16
  32 #define FSI_SLAVE_CONF_VERSION_MASK     GENMASK(15, 12)
  33 #define FSI_SLAVE_CONF_VERSION_SHIFT    12
  34 #define FSI_SLAVE_CONF_TYPE_MASK        GENMASK(11, 4)
  35 #define FSI_SLAVE_CONF_TYPE_SHIFT       4
  36 #define FSI_SLAVE_CONF_CRC_SHIFT        4
  37 #define FSI_SLAVE_CONF_CRC_MASK         GENMASK(3, 0)
  38 #define FSI_SLAVE_CONF_DATA_BITS        28
  39
  40 #define FSI_PEEK_BASE                   0x410
  41
  42 static const int engine_page_size = 0x400;
  43
  44 #define FSI_SLAVE_BASE                  0x800
  45
  46 /*
  47  * FSI slave engine control register offsets
  48  */
  49 #define FSI_SMODE               0x0     /* R/W: Mode register */
  50 #define FSI_SISC                0x8     /* R/W: Interrupt condition */
  51 #define FSI_SSTAT               0x14    /* R  : Slave status */
  52 #define FSI_LLMODE              0x100   /* R/W: Link layer mode register */
  53
  54 /*
  55  * SMODE fields
  56  */
  57 #define FSI_SMODE_WSC           0x80000000      /* Warm start done */
  58 #define FSI_SMODE_ECRC          0x20000000      /* Hw CRC check */
  59 #define FSI_SMODE_SID_SHIFT     24              /* ID shift */
  60 #define FSI_SMODE_SID_MASK      3               /* ID Mask */
  61 #define FSI_SMODE_ED_SHIFT      20              /* Echo delay shift */
  62 #define FSI_SMODE_ED_MASK       0xf             /* Echo delay mask */
  63 #define FSI_SMODE_SD_SHIFT      16              /* Send delay shift */
  64 #define FSI_SMODE_SD_MASK       0xf             /* Send delay mask */
  65 #define FSI_SMODE_LBCRR_SHIFT   8               /* Clk ratio shift */
  66 #define FSI_SMODE_LBCRR_MASK    0xf             /* Clk ratio mask */
  67
  68 /*
  69  * LLMODE fields
  70  */
  71 #define FSI_LLMODE_ASYNC        0x1
  72
  73 #define FSI_SLAVE_SIZE_23b              0x800000
  74
  75 static DEFINE_IDA(master_ida);
  76
  77 struct fsi_slave {
  78         struct device           dev;
  79         struct fsi_master       *master;
  80         int                     id;
  81         int                     link;
  82         uint32_t                size;   /* size of slave address space */
  83 };
  84
  85 #define to_fsi_master(d) container_of(d, struct fsi_master, dev)
  86 #define to_fsi_slave(d) container_of(d, struct fsi_slave, dev)
  87
  88 static const int slave_retries = 2;
  89 static int discard_errors;
  90
  91 static int fsi_master_read(struct fsi_master *master, int link,
  92                 uint8_t slave_id, uint32_t addr, void *val, size_t size);
  93 static int fsi_master_write(struct fsi_master *master, int link,
  94                 uint8_t slave_id, uint32_t addr, const void *val, size_t size);
  95 static int fsi_master_break(struct fsi_master *master, int link);
  96
  97 /*
  98  * fsi_device_read() / fsi_device_write() / fsi_device_peek()
  99  *
 100  * FSI endpoint-device support
 101  *
 102  * Read / write / peek accessors for a client
 103  *
 104  * Parameters:
 105  * dev:  Structure passed to FSI client device drivers on probe().
 106  * addr: FSI address of given device.  Client should pass in its base address
 107  *       plus desired offset to access its register space.
 108  * val:  For read/peek this is the value read at the specified address. For
 109  *       write this is value to write to the specified address.
 110  *       The data in val must be FSI bus endian (big endian).
 111  * size: Size in bytes of the operation.  Sizes supported are 1, 2 and 4 bytes.
 112  *       Addresses must be aligned on size boundaries or an error will result.
 113  */
 114 int fsi_device_read(struct fsi_device *dev, uint32_t addr, void *val,
 115                 size_t size)
 116 {
 117         if (addr > dev->size || size > dev->size || addr > dev->size - size)
 118                 return -EINVAL;
 119
 120         return fsi_slave_read(dev->slave, dev->addr + addr, val, size);
 121 }
 122 EXPORT_SYMBOL_GPL(fsi_device_read);
 123
 124 int fsi_device_write(struct fsi_device *dev, uint32_t addr, const void *val,
 125                 size_t size)
 126 {
 127         if (addr > dev->size || size > dev->size || addr > dev->size - size)
 128                 return -EINVAL;
 129
 130         return fsi_slave_write(dev->slave, dev->addr + addr, val, size);
 131 }
 132 EXPORT_SYMBOL_GPL(fsi_device_write);
 133
 134 int fsi_device_peek(struct fsi_device *dev, void *val)
 135 {
 136         uint32_t addr = FSI_PEEK_BASE + ((dev->unit - 2) * sizeof(uint32_t));
 137
 138         return fsi_slave_read(dev->slave, addr, val, sizeof(uint32_t));
 139 }
 140
 141 static void fsi_device_release(struct device *_device)
 142 {
 143         struct fsi_device *device = to_fsi_dev(_device);
 144
 145         kfree(device);
 146 }
 147
 148 static struct fsi_device *fsi_create_device(struct fsi_slave *slave)
 149 {
 150         struct fsi_device *dev;
 151
 152         dev = kzalloc(sizeof(*dev), GFP_KERNEL);
 153         if (!dev)
 154                 return NULL;
 155
 156         dev->dev.parent = &slave->dev;
 157         dev->dev.bus = &fsi_bus_type;
 158         dev->dev.release = fsi_device_release;
 159
 160         return dev;
 161 }
 162
 163 /* FSI slave support */
 164 static int fsi_slave_calc_addr(struct fsi_slave *slave, uint32_t *addrp,
 165                 uint8_t *idp)
 166 {
 167         uint32_t addr = *addrp;
 168         uint8_t id = *idp;
 169
 170         if (addr > slave->size)
 171                 return -EINVAL;
 172
 173         /* For 23 bit addressing, we encode the extra two bits in the slave
 174          * id (and the slave's actual ID needs to be 0).
 175          */
 176         if (addr > 0x1fffff) {
 177                 if (slave->id != 0)
 178                         return -EINVAL;
 179                 id = (addr >> 21) & 0x3;
 180                 addr &= 0x1fffff;
 181         }
 182
 183         *addrp = addr;
 184         *idp = id;
 185         return 0;
 186 }
 187
 188 int fsi_slave_report_and_clear_errors(struct fsi_slave *slave)
 189 {
 190         struct fsi_master *master = slave->master;
 191         uint32_t irq, stat;
 192         int rc, link;
 193         uint8_t id;
 194
 195         link = slave->link;
 196         id = slave->id;
 197
 198         rc = fsi_master_read(master, link, id, FSI_SLAVE_BASE + FSI_SISC,
 199                         &irq, sizeof(irq));
 200         if (rc)
 201                 return rc;
 202
 203         rc =  fsi_master_read(master, link, id, FSI_SLAVE_BASE + FSI_SSTAT,
 204                         &stat, sizeof(stat));
 205         if (rc)
 206                 return rc;
 207
 208         dev_info(&slave->dev, "status: 0x%08x, sisc: 0x%08x\n",
 209                         be32_to_cpu(stat), be32_to_cpu(irq));
 210
 211         /* clear interrupts */
 212         return fsi_master_write(master, link, id, FSI_SLAVE_BASE + FSI_SISC,
 213                         &irq, sizeof(irq));
 214 }
 215
 216 static int fsi_slave_set_smode(struct fsi_master *master, int link, int id);
 217
 218 int fsi_slave_handle_error(struct fsi_slave *slave, bool write, uint32_t addr,
 219                 size_t size)
 220 {
 221         struct fsi_master *master = slave->master;
 222         int rc, link;
 223         uint32_t reg;
 224         uint8_t id;
 225
 226         if (discard_errors)
 227                 return -1;
 228
 229         link = slave->link;
 230         id = slave->id;
 231
 232         dev_dbg(&slave->dev, "handling error on %s to 0x%08x[%zd]",
 233                         write ? "write" : "read", addr, size);
 234
 235         /* try a simple clear of error conditions, which may fail if we've lost
 236          * communication with the slave
 237          */
 238         rc = fsi_slave_report_and_clear_errors(slave);
 239         if (!rc)
 240                 return 0;
 241
 242         /* send a TERM and retry */
 243         if (master->term) {
 244                 rc = master->term(master, link, id);
 245                 if (!rc) {
 246                         rc = fsi_master_read(master, link, id, 0,
 247                                         &reg, sizeof(reg));
 248                         if (!rc)
 249                                 rc = fsi_slave_report_and_clear_errors(slave);
 250                         if (!rc)
 251                                 return 0;
 252                 }
 253         }
 254
 255         /* getting serious, reset the slave via BREAK */
 256         rc = fsi_master_break(master, link);
 257         if (rc)
 258                 return rc;
 259
 260         rc = fsi_slave_set_smode(master, link, id);
 261         if (rc)
 262                 return rc;
 263
 264         return fsi_slave_report_and_clear_errors(slave);
 265 }
 266
 267 int fsi_slave_read(struct fsi_slave *slave, uint32_t addr,
 268                         void *val, size_t size)
 269 {
 270         uint8_t id = slave->id;
 271         int rc, err_rc, i;
 272
 273         rc = fsi_slave_calc_addr(slave, &addr, &id);
 274         if (rc)
 275                 return rc;
 276
 277         for (i = 0; i < slave_retries; i++) {
 278                 rc = fsi_master_read(slave->master, slave->link,
 279                                 id, addr, val, size);
 280                 if (!rc)
 281                         break;
 282
 283                 err_rc = fsi_slave_handle_error(slave, false, addr, size);
 284                 if (err_rc)
 285                         break;
 286         }
 287
 288         return rc;
 289 }
 290 EXPORT_SYMBOL_GPL(fsi_slave_read);
 291
 292 int fsi_slave_write(struct fsi_slave *slave, uint32_t addr,
 293                         const void *val, size_t size)
 294 {
 295         uint8_t id = slave->id;
 296         int rc, err_rc, i;
 297
 298         rc = fsi_slave_calc_addr(slave, &addr, &id);
 299         if (rc)
 300                 return rc;
 301
 302         for (i = 0; i < slave_retries; i++) {
 303                 rc = fsi_master_write(slave->master, slave->link,
 304                                 id, addr, val, size);
 305                 if (!rc)
 306                         break;
 307
 308                 err_rc = fsi_slave_handle_error(slave, true, addr, size);
 309                 if (err_rc)
 310                         break;
 311         }
 312
 313         return rc;
 314 }
 315 EXPORT_SYMBOL_GPL(fsi_slave_write);
 316
 317 extern int fsi_slave_claim_range(struct fsi_slave *slave,
 318                 uint32_t addr, uint32_t size)
 319 {
 320         if (addr + size < addr)
 321                 return -EINVAL;
 322
 323         if (addr + size > slave->size)
 324                 return -EINVAL;
 325
 326         /* todo: check for overlapping claims */
 327         return 0;
 328 }
 329 EXPORT_SYMBOL_GPL(fsi_slave_claim_range);
 330
 331 extern void fsi_slave_release_range(struct fsi_slave *slave,
 332                 uint32_t addr, uint32_t size)
 333 {
 334 }
 335 EXPORT_SYMBOL_GPL(fsi_slave_release_range);
 336
 337 static int fsi_slave_scan(struct fsi_slave *slave)
 338 {
 339         uint32_t engine_addr;
 340         uint32_t conf;
 341         int rc, i;
 342
 343         /*
 344          * scan engines
 345          *
 346          * We keep the peek mode and slave engines for the core; so start
 347          * at the third slot in the configuration table. We also need to
 348          * skip the chip ID entry at the start of the address space.
 349          */
 350         engine_addr = engine_page_size * 3;
 351         for (i = 2; i < engine_page_size / sizeof(uint32_t); i++) {
 352                 uint8_t slots, version, type, crc;
 353                 struct fsi_device *dev;
 354
 355                 rc = fsi_slave_read(slave, (i + 1) * sizeof(conf),
 356                                 &conf, sizeof(conf));
 357                 if (rc) {
 358                         dev_warn(&slave->dev,
 359                                 "error reading slave registers\n");
 360                         return -1;
 361                 }
 362                 conf = be32_to_cpu(conf);
 363
 364                 crc = crc4(0, conf, 32);
 365                 if (crc) {
 366                         dev_warn(&slave->dev,
 367                                 "crc error in slave register at 0x%04x\n",
 368                                 i);
 369                         return -1;
 370                 }
 371
 372                 slots = (conf & FSI_SLAVE_CONF_SLOTS_MASK)
 373                         >> FSI_SLAVE_CONF_SLOTS_SHIFT;
 374                 version = (conf & FSI_SLAVE_CONF_VERSION_MASK)
 375                         >> FSI_SLAVE_CONF_VERSION_SHIFT;
 376                 type = (conf & FSI_SLAVE_CONF_TYPE_MASK)
 377                         >> FSI_SLAVE_CONF_TYPE_SHIFT;
 378
 379                 /*
 380                  * Unused address areas are marked by a zero type value; this
 381                  * skips the defined address areas
 382                  */
 383                 if (type != 0 && slots != 0) {
 384
 385                         /* create device */
 386                         dev = fsi_create_device(slave);
 387                         if (!dev)
 388                                 return -ENOMEM;
 389
 390                         dev->slave = slave;
 391                         dev->engine_type = type;
 392                         dev->version = version;
 393                         dev->unit = i;
 394                         dev->addr = engine_addr;
 395                         dev->size = slots * engine_page_size;
 396
 397                         dev_dbg(&slave->dev,
 398                         "engine[%i]: type %x, version %x, addr %x size %x\n",
 399                                         dev->unit, dev->engine_type, version,
 400                                         dev->addr, dev->size);
 401
 402                         dev_set_name(&dev->dev, "%02x:%02x:%02x:%02x",
 403                                         slave->master->idx, slave->link,
 404                                         slave->id, i - 2);
 405
 406                         rc = device_register(&dev->dev);
 407                         if (rc) {
 408                                 dev_warn(&slave->dev, "add failed: %d\n", rc);
 409                                 put_device(&dev->dev);
 410                         }
 411                 }
 412
 413                 engine_addr += slots * engine_page_size;
 414
 415                 if (!(conf & FSI_SLAVE_CONF_NEXT_MASK))
 416                         break;
 417         }
 418
 419         return 0;
 420 }
 421
 422 static ssize_t fsi_slave_sysfs_raw_read(struct file *file,
 423                 struct kobject *kobj, struct bin_attribute *attr, char *buf,
 424                 loff_t off, size_t count)
 425 {
 426         struct fsi_slave *slave = to_fsi_slave(kobj_to_dev(kobj));
 427         size_t total_len, read_len;
 428         int rc;
 429
 430         if (off < 0)
 431                 return -EINVAL;
 432
 433         if (off > 0xffffffff || count > 0xffffffff || off + count > 0xffffffff)
 434                 return -EINVAL;
 435
 436         for (total_len = 0; total_len < count; total_len += read_len) {
 437                 read_len = min_t(size_t, count, 4);
 438                 read_len -= off & 0x3;
 439
 440                 rc = fsi_slave_read(slave, off, buf + total_len, read_len);
 441                 if (rc)
 442                         return rc;
 443
 444                 off += read_len;
 445         }
 446
 447         return count;
 448 }
 449
 450 static ssize_t fsi_slave_sysfs_raw_write(struct file *file,
 451                 struct kobject *kobj, struct bin_attribute *attr,
 452                 char *buf, loff_t off, size_t count)
 453 {
 454         struct fsi_slave *slave = to_fsi_slave(kobj_to_dev(kobj));
 455         size_t total_len, write_len;
 456         int rc;
 457
 458         if (off < 0)
 459                 return -EINVAL;
 460
 461         if (off > 0xffffffff || count > 0xffffffff || off + count > 0xffffffff)
 462                 return -EINVAL;
 463
 464         for (total_len = 0; total_len < count; total_len += write_len) {
 465                 write_len = min_t(size_t, count, 4);
 466                 write_len -= off & 0x3;
 467
 468                 rc = fsi_slave_write(slave, off, buf + total_len, write_len);
 469                 if (rc)
 470                         return rc;
 471
 472                 off += write_len;
 473         }
 474
 475         return count;
 476 }
 477
 478 static struct bin_attribute fsi_slave_raw_attr = {
 479         .attr = {
 480                 .name = "raw",
 481                 .mode = 0600,
 482         },
 483         .size = 0,
 484         .read = fsi_slave_sysfs_raw_read,
 485         .write = fsi_slave_sysfs_raw_write,
 486 };
 487
 488 static ssize_t fsi_slave_sysfs_term_write(struct file *file,
 489                 struct kobject *kobj, struct bin_attribute *attr,
 490                 char *buf, loff_t off, size_t count)
 491 {
 492         struct fsi_slave *slave = to_fsi_slave(kobj_to_dev(kobj));
 493         struct fsi_master *master = slave->master;
 494
 495         if (!master->term)
 496                 return -ENODEV;
 497
 498         master->term(master, slave->link, slave->id);
 499         return count;
 500 }
 501
 502 static struct bin_attribute fsi_slave_term_attr = {
 503         .attr = {
 504                 .name = "term",
 505                 .mode = 0200,
 506         },
 507         .size = 0,
 508         .write = fsi_slave_sysfs_term_write,
 509 };
 510
 511 /* Encode slave local bus echo delay */
 512 static inline uint32_t fsi_smode_echodly(int x)
 513 {
 514         return (x & FSI_SMODE_ED_MASK) << FSI_SMODE_ED_SHIFT;
 515 }
 516
 517 /* Encode slave local bus send delay */
 518 static inline uint32_t fsi_smode_senddly(int x)
 519 {
 520         return (x & FSI_SMODE_SD_MASK) << FSI_SMODE_SD_SHIFT;
 521 }
 522
 523 /* Encode slave local bus clock rate ratio */
 524 static inline uint32_t fsi_smode_lbcrr(int x)
 525 {
 526         return (x & FSI_SMODE_LBCRR_MASK) << FSI_SMODE_LBCRR_SHIFT;
 527 }
 528
 529 /* Encode slave ID */
 530 static inline uint32_t fsi_smode_sid(int x)
 531 {
 532         return (x & FSI_SMODE_SID_MASK) << FSI_SMODE_SID_SHIFT;
 533 }
 534
 535 static const uint32_t fsi_slave_smode(int id)
 536 {
 537         return FSI_SMODE_WSC | FSI_SMODE_ECRC
 538                 | fsi_smode_sid(id)
 539                 | fsi_smode_echodly(0xf) | fsi_smode_senddly(0xf)
 540                 | fsi_smode_lbcrr(0x8);
 541 }
 542
 543 static int fsi_slave_set_smode(struct fsi_master *master, int link, int id)
 544 {
 545         uint32_t smode;
 546
 547         /* set our smode register with the slave ID field to 0; this enables
 548          * extended slave addressing
 549          */
 550         smode = fsi_slave_smode(id);
 551         smode = cpu_to_be32(smode);
 552
 553         return fsi_master_write(master, link, id, FSI_SLAVE_BASE + FSI_SMODE,
 554                         &smode, sizeof(smode));
 555 }
 556
 557 static void fsi_slave_release(struct device *dev)
 558 {
 559         struct fsi_slave *slave = to_fsi_slave(dev);
 560
 561         kfree(slave);
 562 }
 563
 564 static int fsi_slave_init(struct fsi_master *master, int link, uint8_t id)
 565 {
 566         uint32_t chip_id, llmode;
 567         struct fsi_slave *slave;
 568         uint8_t crc;
 569         int rc;
 570
 571         /* Currently, we only support single slaves on a link, and use the
 572          * full 23-bit address range
 573          */
 574         if (id != 0)
 575                 return -EINVAL;
 576
 577         rc = fsi_master_read(master, link, id, 0, &chip_id, sizeof(chip_id));
 578         if (rc) {
 579                 dev_dbg(&master->dev, "can't read slave %02x:%02x %d\n",
 580                                 link, id, rc);
 581                 return -ENODEV;
 582         }
 583         chip_id = be32_to_cpu(chip_id);
 584
 585         crc = crc4(0, chip_id, 32);
 586         if (crc) {
 587                 dev_warn(&master->dev, "slave %02x:%02x invalid chip id CRC!\n",
 588                                 link, id);
 589                 return -EIO;
 590         }
 591
 592         dev_info(&master->dev, "fsi: found chip %08x at %02x:%02x:%02x\n",
 593                         chip_id, master->idx, link, id);
 594
 595         rc = fsi_slave_set_smode(master, link, id);
 596         if (rc) {
 597                 dev_warn(&master->dev,
 598                                 "can't set smode on slave:%02x:%02x %d\n",
 599                                 link, id, rc);
 600                 return -ENODEV;
 601         }
 602
 603         /* If we're behind a master that doesn't provide a self-running bus
 604          * clock, put the slave into async mode
 605          */
 606         if (master->flags & FSI_MASTER_FLAG_SWCLOCK) {
 607                 llmode = cpu_to_be32(FSI_LLMODE_ASYNC);
 608                 rc = fsi_master_write(master, link, id,
 609                                 FSI_SLAVE_BASE + FSI_LLMODE,
 610                                 &llmode, sizeof(llmode));
 611                 if (rc)
 612                         dev_warn(&master->dev,
 613                                 "can't set llmode on slave:%02x:%02x %d\n",
 614                                 link, id, rc);
 615         }
 616
 617         /* We can communicate with a slave; create the slave device and
 618          * register.
 619          */
 620         slave = kzalloc(sizeof(*slave), GFP_KERNEL);
 621         if (!slave)
 622                 return -ENOMEM;
 623
 624         slave->master = master;
 625         slave->dev.parent = &master->dev;
 626         slave->dev.release = fsi_slave_release;
 627         slave->link = link;
 628         slave->id = id;
 629         slave->size = FSI_SLAVE_SIZE_23b;
 630
 631         dev_set_name(&slave->dev, "slave@%02x:%02x", link, id);
 632         rc = device_register(&slave->dev);
 633         if (rc < 0) {
 634                 dev_warn(&master->dev, "failed to create slave device: %d\n",
 635                                 rc);
 636                 put_device(&slave->dev);
 637                 return rc;
 638         }
 639
 640         rc = device_create_bin_file(&slave->dev, &fsi_slave_raw_attr);
 641         if (rc)
 642                 dev_warn(&slave->dev, "failed to create raw attr: %d\n", rc);
 643
 644         rc = device_create_bin_file(&slave->dev, &fsi_slave_term_attr);
 645         if (rc)
 646                 dev_warn(&slave->dev, "failed to create term attr: %d\n", rc);
 647
 648         rc = fsi_slave_scan(slave);
 649         if (rc)
 650                 dev_dbg(&master->dev, "failed during slave scan with: %d\n",
 651                                 rc);
 652
 653         return rc;
 654 }
 655
 656 /* FSI master support */
 657 static int fsi_check_access(uint32_t addr, size_t size)
 658 {
 659         if (size != 1 && size != 2 && size != 4)
 660                 return -EINVAL;
 661
 662         if ((addr & 0x3) != (size & 0x3))
 663                 return -EINVAL;
 664
 665         return 0;
 666 }
 667
 668 static int fsi_master_read(struct fsi_master *master, int link,
 669                 uint8_t slave_id, uint32_t addr, void *val, size_t size)
 670 {
 671         int rc;
 672
 673         trace_fsi_master_read(master, link, slave_id, addr, size);
 674
 675         rc = fsi_check_access(addr, size);
 676         if (!rc)
 677                 rc = master->read(master, link, slave_id, addr, val, size);
 678
 679         trace_fsi_master_rw_result(master, link, slave_id, addr, size,
 680                         false, val, rc);
 681
 682         return rc;
 683 }
 684
 685 static int fsi_master_write(struct fsi_master *master, int link,
 686                 uint8_t slave_id, uint32_t addr, const void *val, size_t size)
 687 {
 688         int rc;
 689
 690         trace_fsi_master_write(master, link, slave_id, addr, size, val);
 691
 692         rc = fsi_check_access(addr, size);
 693         if (!rc)
 694                 rc = master->write(master, link, slave_id, addr, val, size);
 695
 696         trace_fsi_master_rw_result(master, link, slave_id, addr, size,
 697                         true, val, rc);
 698
 699         return rc;
 700 }
 701
 702 static int fsi_master_link_enable(struct fsi_master *master, int link)
 703 {
 704         if (master->link_enable)
 705                 return master->link_enable(master, link);
 706
 707         return 0;
 708 }
 709
 710 /*
 711  * Issue a break command on this link
 712  */
 713 static int fsi_master_break(struct fsi_master *master, int link)
 714 {
 715         trace_fsi_master_break(master, link);
 716
 717         if (master->send_break)
 718                 return master->send_break(master, link);
 719
 720         return 0;
 721 }
 722
 723 static int fsi_master_scan(struct fsi_master *master)
 724 {
 725         int link, rc;
 726
 727         for (link = 0; link < master->n_links; link++) {
 728                 rc = fsi_master_link_enable(master, link);
 729                 if (rc) {
 730                         dev_dbg(&master->dev,
 731                                 "enable link %d failed: %d\n", link, rc);
 732                         continue;
 733                 }
 734                 rc = fsi_master_break(master, link);
 735                 if (rc) {
 736                         dev_dbg(&master->dev,
 737                                 "break to link %d failed: %d\n", link, rc);
 738                         continue;
 739                 }
 740
 741                 fsi_slave_init(master, link, 0);
 742         }
 743
 744         return 0;
 745 }
 746
 747 static int fsi_slave_remove_device(struct device *dev, void *arg)
 748 {
 749         device_unregister(dev);
 750         return 0;
 751 }
 752
 753 static int fsi_master_remove_slave(struct device *dev, void *arg)
 754 {
 755         device_for_each_child(dev, NULL, fsi_slave_remove_device);
 756         device_unregister(dev);
 757         return 0;
 758 }
 759
 760 static void fsi_master_unscan(struct fsi_master *master)
 761 {
 762         device_for_each_child(&master->dev, NULL, fsi_master_remove_slave);
 763 }
 764
 765 static ssize_t master_rescan_store(struct device *dev,
 766                 struct device_attribute *attr, const char *buf, size_t count)
 767 {
 768         struct fsi_master *master = to_fsi_master(dev);
 769         int rc;
 770
 771         fsi_master_unscan(master);
 772         rc = fsi_master_scan(master);
 773         if (rc < 0)
 774                 return rc;
 775
 776         return count;
 777 }
 778
 779 static DEVICE_ATTR(rescan, 0200, NULL, master_rescan_store);
 780
 781 static ssize_t master_break_store(struct device *dev,
 782                 struct device_attribute *attr, const char *buf, size_t count)
 783 {
 784         struct fsi_master *master = to_fsi_master(dev);
 785
 786         fsi_master_break(master, 0);
 787
 788         return count;
 789 }
 790
 791 static DEVICE_ATTR(break, 0200, NULL, master_break_store);
 792
 793 int fsi_master_register(struct fsi_master *master)
 794 {
 795         int rc;
 796
 797         if (!master)
 798                 return -EINVAL;
 799
 800         master->idx = ida_simple_get(&master_ida, 0, INT_MAX, GFP_KERNEL);
 801         dev_set_name(&master->dev, "fsi%d", master->idx);
 802
 803         rc = device_register(&master->dev);
 804         if (rc) {
 805                 ida_simple_remove(&master_ida, master->idx);
 806                 return rc;
 807         }
 808
 809         rc = device_create_file(&master->dev, &dev_attr_rescan);
 810         if (rc) {
 811                 device_unregister(&master->dev);
 812                 ida_simple_remove(&master_ida, master->idx);
 813                 return rc;
 814         }
 815
 816         rc = device_create_file(&master->dev, &dev_attr_break);
 817         if (rc) {
 818                 device_unregister(&master->dev);
 819                 ida_simple_remove(&master_ida, master->idx);
 820                 return rc;
 821         }
 822
 823         fsi_master_scan(master);
 824
 825         return 0;
 826 }
 827 EXPORT_SYMBOL_GPL(fsi_master_register);
 828
 829 void fsi_master_unregister(struct fsi_master *master)
 830 {
 831         if (master->idx >= 0) {
 832                 ida_simple_remove(&master_ida, master->idx);
 833                 master->idx = -1;
 834         }
 835
 836         fsi_master_unscan(master);
 837         device_unregister(&master->dev);
 838 }
 839 EXPORT_SYMBOL_GPL(fsi_master_unregister);
 840
 841 /* FSI core & Linux bus type definitions */
 842
 843 static int fsi_bus_match(struct device *dev, struct device_driver *drv)
 844 {
 845         struct fsi_device *fsi_dev = to_fsi_dev(dev);
 846         struct fsi_driver *fsi_drv = to_fsi_drv(drv);
 847         const struct fsi_device_id *id;
 848
 849         if (!fsi_drv->id_table)
 850                 return 0;
 851
 852         for (id = fsi_drv->id_table; id->engine_type; id++) {
 853                 if (id->engine_type != fsi_dev->engine_type)
 854                         continue;
 855                 if (id->version == FSI_VERSION_ANY ||
 856                                 id->version == fsi_dev->version)
 857                         return 1;
 858         }
 859
 860         return 0;
 861 }
 862
 863 int fsi_driver_register(struct fsi_driver *fsi_drv)
 864 {
 865         if (!fsi_drv)
 866                 return -EINVAL;
 867         if (!fsi_drv->id_table)
 868                 return -EINVAL;
 869
 870         return driver_register(&fsi_drv->drv);
 871 }
 872 EXPORT_SYMBOL_GPL(fsi_driver_register);
 873
 874 void fsi_driver_unregister(struct fsi_driver *fsi_drv)
 875 {
 876         driver_unregister(&fsi_drv->drv);
 877 }
 878 EXPORT_SYMBOL_GPL(fsi_driver_unregister);
 879
 880 struct bus_type fsi_bus_type = {
 881         .name           = "fsi",
 882         .match          = fsi_bus_match,
 883 };
 884 EXPORT_SYMBOL_GPL(fsi_bus_type);
 885
 886 static int fsi_init(void)
 887 {
 888         return bus_register(&fsi_bus_type);
 889 }
 890
 891 static void fsi_exit(void)
 892 {
 893         bus_unregister(&fsi_bus_type);
 894 }
 895
 896 module_init(fsi_init);
 897 module_exit(fsi_exit);
 898 module_param(discard_errors, int, 0664);
 899 MODULE_LICENSE("GPL");
 900 MODULE_PARM_DESC(discard_errors, "Don't invoke error handling on bus accesses");