linux/drivers/fsi/fsi-core.c
<<
>>
Prefs
   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 * FSI core driver
   4 *
   5 * Copyright (C) IBM Corporation 2016
   6 *
   7 * TODO:
   8 *  - Rework topology
   9 *  - s/chip_id/chip_loc
  10 *  - s/cfam/chip (cfam_id -> chip_id etc...)
  11 */
  12
  13#include <linux/crc4.h>
  14#include <linux/device.h>
  15#include <linux/fsi.h>
  16#include <linux/idr.h>
  17#include <linux/module.h>
  18#include <linux/of.h>
  19#include <linux/slab.h>
  20#include <linux/bitops.h>
  21#include <linux/cdev.h>
  22#include <linux/fs.h>
  23#include <linux/uaccess.h>
  24
  25#include "fsi-master.h"
  26
  27#define CREATE_TRACE_POINTS
  28#include <trace/events/fsi.h>
  29
  30#define FSI_SLAVE_CONF_NEXT_MASK        GENMASK(31, 31)
  31#define FSI_SLAVE_CONF_SLOTS_MASK       GENMASK(23, 16)
  32#define FSI_SLAVE_CONF_SLOTS_SHIFT      16
  33#define FSI_SLAVE_CONF_VERSION_MASK     GENMASK(15, 12)
  34#define FSI_SLAVE_CONF_VERSION_SHIFT    12
  35#define FSI_SLAVE_CONF_TYPE_MASK        GENMASK(11, 4)
  36#define FSI_SLAVE_CONF_TYPE_SHIFT       4
  37#define FSI_SLAVE_CONF_CRC_SHIFT        4
  38#define FSI_SLAVE_CONF_CRC_MASK         GENMASK(3, 0)
  39#define FSI_SLAVE_CONF_DATA_BITS        28
  40
  41#define FSI_PEEK_BASE                   0x410
  42
  43static const int engine_page_size = 0x400;
  44
  45#define FSI_SLAVE_BASE                  0x800
  46
  47/*
  48 * FSI slave engine control register offsets
  49 */
  50#define FSI_SMODE               0x0     /* R/W: Mode register */
  51#define FSI_SISC                0x8     /* R/W: Interrupt condition */
  52#define FSI_SSTAT               0x14    /* R  : Slave status */
  53#define FSI_SLBUS               0x30    /* W  : LBUS Ownership */
  54#define FSI_LLMODE              0x100   /* R/W: Link layer mode register */
  55
  56/*
  57 * SMODE fields
  58 */
  59#define FSI_SMODE_WSC           0x80000000      /* Warm start done */
  60#define FSI_SMODE_ECRC          0x20000000      /* Hw CRC check */
  61#define FSI_SMODE_SID_SHIFT     24              /* ID shift */
  62#define FSI_SMODE_SID_MASK      3               /* ID Mask */
  63#define FSI_SMODE_ED_SHIFT      20              /* Echo delay shift */
  64#define FSI_SMODE_ED_MASK       0xf             /* Echo delay mask */
  65#define FSI_SMODE_SD_SHIFT      16              /* Send delay shift */
  66#define FSI_SMODE_SD_MASK       0xf             /* Send delay mask */
  67#define FSI_SMODE_LBCRR_SHIFT   8               /* Clk ratio shift */
  68#define FSI_SMODE_LBCRR_MASK    0xf             /* Clk ratio mask */
  69
  70/*
  71 * SLBUS fields
  72 */
  73#define FSI_SLBUS_FORCE         0x80000000      /* Force LBUS ownership */
  74
  75/*
  76 * LLMODE fields
  77 */
  78#define FSI_LLMODE_ASYNC        0x1
  79
  80#define FSI_SLAVE_SIZE_23b              0x800000
  81
  82static DEFINE_IDA(master_ida);
  83
  84struct fsi_slave {
  85        struct device           dev;
  86        struct fsi_master       *master;
  87        struct cdev             cdev;
  88        int                     cdev_idx;
  89        int                     id;     /* FSI address */
  90        int                     link;   /* FSI link# */
  91        u32                     cfam_id;
  92        int                     chip_id;
  93        uint32_t                size;   /* size of slave address space */
  94        u8                      t_send_delay;
  95        u8                      t_echo_delay;
  96};
  97
  98#define to_fsi_master(d) container_of(d, struct fsi_master, dev)
  99#define to_fsi_slave(d) container_of(d, struct fsi_slave, dev)
 100
 101static const int slave_retries = 2;
 102static int discard_errors;
 103
 104static dev_t fsi_base_dev;
 105static DEFINE_IDA(fsi_minor_ida);
 106#define FSI_CHAR_MAX_DEVICES    0x1000
 107
 108/* Legacy /dev numbering: 4 devices per chip, 16 chips */
 109#define FSI_CHAR_LEGACY_TOP     64
 110
 111static int fsi_master_read(struct fsi_master *master, int link,
 112                uint8_t slave_id, uint32_t addr, void *val, size_t size);
 113static int fsi_master_write(struct fsi_master *master, int link,
 114                uint8_t slave_id, uint32_t addr, const void *val, size_t size);
 115static int fsi_master_break(struct fsi_master *master, int link);
 116
 117/*
 118 * fsi_device_read() / fsi_device_write() / fsi_device_peek()
 119 *
 120 * FSI endpoint-device support
 121 *
 122 * Read / write / peek accessors for a client
 123 *
 124 * Parameters:
 125 * dev:  Structure passed to FSI client device drivers on probe().
 126 * addr: FSI address of given device.  Client should pass in its base address
 127 *       plus desired offset to access its register space.
 128 * val:  For read/peek this is the value read at the specified address. For
 129 *       write this is value to write to the specified address.
 130 *       The data in val must be FSI bus endian (big endian).
 131 * size: Size in bytes of the operation.  Sizes supported are 1, 2 and 4 bytes.
 132 *       Addresses must be aligned on size boundaries or an error will result.
 133 */
 134int fsi_device_read(struct fsi_device *dev, uint32_t addr, void *val,
 135                size_t size)
 136{
 137        if (addr > dev->size || size > dev->size || addr > dev->size - size)
 138                return -EINVAL;
 139
 140        return fsi_slave_read(dev->slave, dev->addr + addr, val, size);
 141}
 142EXPORT_SYMBOL_GPL(fsi_device_read);
 143
 144int fsi_device_write(struct fsi_device *dev, uint32_t addr, const void *val,
 145                size_t size)
 146{
 147        if (addr > dev->size || size > dev->size || addr > dev->size - size)
 148                return -EINVAL;
 149
 150        return fsi_slave_write(dev->slave, dev->addr + addr, val, size);
 151}
 152EXPORT_SYMBOL_GPL(fsi_device_write);
 153
 154int fsi_device_peek(struct fsi_device *dev, void *val)
 155{
 156        uint32_t addr = FSI_PEEK_BASE + ((dev->unit - 2) * sizeof(uint32_t));
 157
 158        return fsi_slave_read(dev->slave, addr, val, sizeof(uint32_t));
 159}
 160
 161static void fsi_device_release(struct device *_device)
 162{
 163        struct fsi_device *device = to_fsi_dev(_device);
 164
 165        of_node_put(device->dev.of_node);
 166        kfree(device);
 167}
 168
 169static struct fsi_device *fsi_create_device(struct fsi_slave *slave)
 170{
 171        struct fsi_device *dev;
 172
 173        dev = kzalloc(sizeof(*dev), GFP_KERNEL);
 174        if (!dev)
 175                return NULL;
 176
 177        dev->dev.parent = &slave->dev;
 178        dev->dev.bus = &fsi_bus_type;
 179        dev->dev.release = fsi_device_release;
 180
 181        return dev;
 182}
 183
 184/* FSI slave support */
 185static int fsi_slave_calc_addr(struct fsi_slave *slave, uint32_t *addrp,
 186                uint8_t *idp)
 187{
 188        uint32_t addr = *addrp;
 189        uint8_t id = *idp;
 190
 191        if (addr > slave->size)
 192                return -EINVAL;
 193
 194        /* For 23 bit addressing, we encode the extra two bits in the slave
 195         * id (and the slave's actual ID needs to be 0).
 196         */
 197        if (addr > 0x1fffff) {
 198                if (slave->id != 0)
 199                        return -EINVAL;
 200                id = (addr >> 21) & 0x3;
 201                addr &= 0x1fffff;
 202        }
 203
 204        *addrp = addr;
 205        *idp = id;
 206        return 0;
 207}
 208
 209static int fsi_slave_report_and_clear_errors(struct fsi_slave *slave)
 210{
 211        struct fsi_master *master = slave->master;
 212        __be32 irq, stat;
 213        int rc, link;
 214        uint8_t id;
 215
 216        link = slave->link;
 217        id = slave->id;
 218
 219        rc = fsi_master_read(master, link, id, FSI_SLAVE_BASE + FSI_SISC,
 220                        &irq, sizeof(irq));
 221        if (rc)
 222                return rc;
 223
 224        rc =  fsi_master_read(master, link, id, FSI_SLAVE_BASE + FSI_SSTAT,
 225                        &stat, sizeof(stat));
 226        if (rc)
 227                return rc;
 228
 229        dev_dbg(&slave->dev, "status: 0x%08x, sisc: 0x%08x\n",
 230                        be32_to_cpu(stat), be32_to_cpu(irq));
 231
 232        /* clear interrupts */
 233        return fsi_master_write(master, link, id, FSI_SLAVE_BASE + FSI_SISC,
 234                        &irq, sizeof(irq));
 235}
 236
 237/* Encode slave local bus echo delay */
 238static inline uint32_t fsi_smode_echodly(int x)
 239{
 240        return (x & FSI_SMODE_ED_MASK) << FSI_SMODE_ED_SHIFT;
 241}
 242
 243/* Encode slave local bus send delay */
 244static inline uint32_t fsi_smode_senddly(int x)
 245{
 246        return (x & FSI_SMODE_SD_MASK) << FSI_SMODE_SD_SHIFT;
 247}
 248
 249/* Encode slave local bus clock rate ratio */
 250static inline uint32_t fsi_smode_lbcrr(int x)
 251{
 252        return (x & FSI_SMODE_LBCRR_MASK) << FSI_SMODE_LBCRR_SHIFT;
 253}
 254
 255/* Encode slave ID */
 256static inline uint32_t fsi_smode_sid(int x)
 257{
 258        return (x & FSI_SMODE_SID_MASK) << FSI_SMODE_SID_SHIFT;
 259}
 260
 261static uint32_t fsi_slave_smode(int id, u8 t_senddly, u8 t_echodly)
 262{
 263        return FSI_SMODE_WSC | FSI_SMODE_ECRC
 264                | fsi_smode_sid(id)
 265                | fsi_smode_echodly(t_echodly - 1) | fsi_smode_senddly(t_senddly - 1)
 266                | fsi_smode_lbcrr(0x8);
 267}
 268
 269static int fsi_slave_set_smode(struct fsi_slave *slave)
 270{
 271        uint32_t smode;
 272        __be32 data;
 273
 274        /* set our smode register with the slave ID field to 0; this enables
 275         * extended slave addressing
 276         */
 277        smode = fsi_slave_smode(slave->id, slave->t_send_delay, slave->t_echo_delay);
 278        data = cpu_to_be32(smode);
 279
 280        return fsi_master_write(slave->master, slave->link, slave->id,
 281                                FSI_SLAVE_BASE + FSI_SMODE,
 282                                &data, sizeof(data));
 283}
 284
 285static int fsi_slave_handle_error(struct fsi_slave *slave, bool write,
 286                                  uint32_t addr, size_t size)
 287{
 288        struct fsi_master *master = slave->master;
 289        int rc, link;
 290        uint32_t reg;
 291        uint8_t id, send_delay, echo_delay;
 292
 293        if (discard_errors)
 294                return -1;
 295
 296        link = slave->link;
 297        id = slave->id;
 298
 299        dev_dbg(&slave->dev, "handling error on %s to 0x%08x[%zd]",
 300                        write ? "write" : "read", addr, size);
 301
 302        /* try a simple clear of error conditions, which may fail if we've lost
 303         * communication with the slave
 304         */
 305        rc = fsi_slave_report_and_clear_errors(slave);
 306        if (!rc)
 307                return 0;
 308
 309        /* send a TERM and retry */
 310        if (master->term) {
 311                rc = master->term(master, link, id);
 312                if (!rc) {
 313                        rc = fsi_master_read(master, link, id, 0,
 314                                        &reg, sizeof(reg));
 315                        if (!rc)
 316                                rc = fsi_slave_report_and_clear_errors(slave);
 317                        if (!rc)
 318                                return 0;
 319                }
 320        }
 321
 322        send_delay = slave->t_send_delay;
 323        echo_delay = slave->t_echo_delay;
 324
 325        /* getting serious, reset the slave via BREAK */
 326        rc = fsi_master_break(master, link);
 327        if (rc)
 328                return rc;
 329
 330        slave->t_send_delay = send_delay;
 331        slave->t_echo_delay = echo_delay;
 332
 333        rc = fsi_slave_set_smode(slave);
 334        if (rc)
 335                return rc;
 336
 337        if (master->link_config)
 338                master->link_config(master, link,
 339                                    slave->t_send_delay,
 340                                    slave->t_echo_delay);
 341
 342        return fsi_slave_report_and_clear_errors(slave);
 343}
 344
 345int fsi_slave_read(struct fsi_slave *slave, uint32_t addr,
 346                        void *val, size_t size)
 347{
 348        uint8_t id = slave->id;
 349        int rc, err_rc, i;
 350
 351        rc = fsi_slave_calc_addr(slave, &addr, &id);
 352        if (rc)
 353                return rc;
 354
 355        for (i = 0; i < slave_retries; i++) {
 356                rc = fsi_master_read(slave->master, slave->link,
 357                                id, addr, val, size);
 358                if (!rc)
 359                        break;
 360
 361                err_rc = fsi_slave_handle_error(slave, false, addr, size);
 362                if (err_rc)
 363                        break;
 364        }
 365
 366        return rc;
 367}
 368EXPORT_SYMBOL_GPL(fsi_slave_read);
 369
 370int fsi_slave_write(struct fsi_slave *slave, uint32_t addr,
 371                        const void *val, size_t size)
 372{
 373        uint8_t id = slave->id;
 374        int rc, err_rc, i;
 375
 376        rc = fsi_slave_calc_addr(slave, &addr, &id);
 377        if (rc)
 378                return rc;
 379
 380        for (i = 0; i < slave_retries; i++) {
 381                rc = fsi_master_write(slave->master, slave->link,
 382                                id, addr, val, size);
 383                if (!rc)
 384                        break;
 385
 386                err_rc = fsi_slave_handle_error(slave, true, addr, size);
 387                if (err_rc)
 388                        break;
 389        }
 390
 391        return rc;
 392}
 393EXPORT_SYMBOL_GPL(fsi_slave_write);
 394
 395extern int fsi_slave_claim_range(struct fsi_slave *slave,
 396                uint32_t addr, uint32_t size)
 397{
 398        if (addr + size < addr)
 399                return -EINVAL;
 400
 401        if (addr + size > slave->size)
 402                return -EINVAL;
 403
 404        /* todo: check for overlapping claims */
 405        return 0;
 406}
 407EXPORT_SYMBOL_GPL(fsi_slave_claim_range);
 408
 409extern void fsi_slave_release_range(struct fsi_slave *slave,
 410                uint32_t addr, uint32_t size)
 411{
 412}
 413EXPORT_SYMBOL_GPL(fsi_slave_release_range);
 414
 415static bool fsi_device_node_matches(struct device *dev, struct device_node *np,
 416                uint32_t addr, uint32_t size)
 417{
 418        unsigned int len, na, ns;
 419        const __be32 *prop;
 420        uint32_t psize;
 421
 422        na = of_n_addr_cells(np);
 423        ns = of_n_size_cells(np);
 424
 425        if (na != 1 || ns != 1)
 426                return false;
 427
 428        prop = of_get_property(np, "reg", &len);
 429        if (!prop || len != 8)
 430                return false;
 431
 432        if (of_read_number(prop, 1) != addr)
 433                return false;
 434
 435        psize = of_read_number(prop + 1, 1);
 436        if (psize != size) {
 437                dev_warn(dev,
 438                        "node %s matches probed address, but not size (got 0x%x, expected 0x%x)",
 439                        of_node_full_name(np), psize, size);
 440        }
 441
 442        return true;
 443}
 444
 445/* Find a matching node for the slave engine at @address, using @size bytes
 446 * of space. Returns NULL if not found, or a matching node with refcount
 447 * already incremented.
 448 */
 449static struct device_node *fsi_device_find_of_node(struct fsi_device *dev)
 450{
 451        struct device_node *parent, *np;
 452
 453        parent = dev_of_node(&dev->slave->dev);
 454        if (!parent)
 455                return NULL;
 456
 457        for_each_child_of_node(parent, np) {
 458                if (fsi_device_node_matches(&dev->dev, np,
 459                                        dev->addr, dev->size))
 460                        return np;
 461        }
 462
 463        return NULL;
 464}
 465
 466static int fsi_slave_scan(struct fsi_slave *slave)
 467{
 468        uint32_t engine_addr;
 469        int rc, i;
 470
 471        /*
 472         * scan engines
 473         *
 474         * We keep the peek mode and slave engines for the core; so start
 475         * at the third slot in the configuration table. We also need to
 476         * skip the chip ID entry at the start of the address space.
 477         */
 478        engine_addr = engine_page_size * 3;
 479        for (i = 2; i < engine_page_size / sizeof(uint32_t); i++) {
 480                uint8_t slots, version, type, crc;
 481                struct fsi_device *dev;
 482                uint32_t conf;
 483                __be32 data;
 484
 485                rc = fsi_slave_read(slave, (i + 1) * sizeof(data),
 486                                &data, sizeof(data));
 487                if (rc) {
 488                        dev_warn(&slave->dev,
 489                                "error reading slave registers\n");
 490                        return -1;
 491                }
 492                conf = be32_to_cpu(data);
 493
 494                crc = crc4(0, conf, 32);
 495                if (crc) {
 496                        dev_warn(&slave->dev,
 497                                "crc error in slave register at 0x%04x\n",
 498                                i);
 499                        return -1;
 500                }
 501
 502                slots = (conf & FSI_SLAVE_CONF_SLOTS_MASK)
 503                        >> FSI_SLAVE_CONF_SLOTS_SHIFT;
 504                version = (conf & FSI_SLAVE_CONF_VERSION_MASK)
 505                        >> FSI_SLAVE_CONF_VERSION_SHIFT;
 506                type = (conf & FSI_SLAVE_CONF_TYPE_MASK)
 507                        >> FSI_SLAVE_CONF_TYPE_SHIFT;
 508
 509                /*
 510                 * Unused address areas are marked by a zero type value; this
 511                 * skips the defined address areas
 512                 */
 513                if (type != 0 && slots != 0) {
 514
 515                        /* create device */
 516                        dev = fsi_create_device(slave);
 517                        if (!dev)
 518                                return -ENOMEM;
 519
 520                        dev->slave = slave;
 521                        dev->engine_type = type;
 522                        dev->version = version;
 523                        dev->unit = i;
 524                        dev->addr = engine_addr;
 525                        dev->size = slots * engine_page_size;
 526
 527                        dev_dbg(&slave->dev,
 528                        "engine[%i]: type %x, version %x, addr %x size %x\n",
 529                                        dev->unit, dev->engine_type, version,
 530                                        dev->addr, dev->size);
 531
 532                        dev_set_name(&dev->dev, "%02x:%02x:%02x:%02x",
 533                                        slave->master->idx, slave->link,
 534                                        slave->id, i - 2);
 535                        dev->dev.of_node = fsi_device_find_of_node(dev);
 536
 537                        rc = device_register(&dev->dev);
 538                        if (rc) {
 539                                dev_warn(&slave->dev, "add failed: %d\n", rc);
 540                                put_device(&dev->dev);
 541                        }
 542                }
 543
 544                engine_addr += slots * engine_page_size;
 545
 546                if (!(conf & FSI_SLAVE_CONF_NEXT_MASK))
 547                        break;
 548        }
 549
 550        return 0;
 551}
 552
 553static unsigned long aligned_access_size(size_t offset, size_t count)
 554{
 555        unsigned long offset_unit, count_unit;
 556
 557        /* Criteria:
 558         *
 559         * 1. Access size must be less than or equal to the maximum access
 560         *    width or the highest power-of-two factor of offset
 561         * 2. Access size must be less than or equal to the amount specified by
 562         *    count
 563         *
 564         * The access width is optimal if we can calculate 1 to be strictly
 565         * equal while still satisfying 2.
 566         */
 567
 568        /* Find 1 by the bottom bit of offset (with a 4 byte access cap) */
 569        offset_unit = BIT(__builtin_ctzl(offset | 4));
 570
 571        /* Find 2 by the top bit of count */
 572        count_unit = BIT(8 * sizeof(unsigned long) - 1 - __builtin_clzl(count));
 573
 574        /* Constrain the maximum access width to the minimum of both criteria */
 575        return BIT(__builtin_ctzl(offset_unit | count_unit));
 576}
 577
 578static ssize_t fsi_slave_sysfs_raw_read(struct file *file,
 579                struct kobject *kobj, struct bin_attribute *attr, char *buf,
 580                loff_t off, size_t count)
 581{
 582        struct fsi_slave *slave = to_fsi_slave(kobj_to_dev(kobj));
 583        size_t total_len, read_len;
 584        int rc;
 585
 586        if (off < 0)
 587                return -EINVAL;
 588
 589        if (off > 0xffffffff || count > 0xffffffff || off + count > 0xffffffff)
 590                return -EINVAL;
 591
 592        for (total_len = 0; total_len < count; total_len += read_len) {
 593                read_len = aligned_access_size(off, count - total_len);
 594
 595                rc = fsi_slave_read(slave, off, buf + total_len, read_len);
 596                if (rc)
 597                        return rc;
 598
 599                off += read_len;
 600        }
 601
 602        return count;
 603}
 604
 605static ssize_t fsi_slave_sysfs_raw_write(struct file *file,
 606                struct kobject *kobj, struct bin_attribute *attr,
 607                char *buf, loff_t off, size_t count)
 608{
 609        struct fsi_slave *slave = to_fsi_slave(kobj_to_dev(kobj));
 610        size_t total_len, write_len;
 611        int rc;
 612
 613        if (off < 0)
 614                return -EINVAL;
 615
 616        if (off > 0xffffffff || count > 0xffffffff || off + count > 0xffffffff)
 617                return -EINVAL;
 618
 619        for (total_len = 0; total_len < count; total_len += write_len) {
 620                write_len = aligned_access_size(off, count - total_len);
 621
 622                rc = fsi_slave_write(slave, off, buf + total_len, write_len);
 623                if (rc)
 624                        return rc;
 625
 626                off += write_len;
 627        }
 628
 629        return count;
 630}
 631
 632static const struct bin_attribute fsi_slave_raw_attr = {
 633        .attr = {
 634                .name = "raw",
 635                .mode = 0600,
 636        },
 637        .size = 0,
 638        .read = fsi_slave_sysfs_raw_read,
 639        .write = fsi_slave_sysfs_raw_write,
 640};
 641
 642static void fsi_slave_release(struct device *dev)
 643{
 644        struct fsi_slave *slave = to_fsi_slave(dev);
 645
 646        fsi_free_minor(slave->dev.devt);
 647        of_node_put(dev->of_node);
 648        kfree(slave);
 649}
 650
 651static bool fsi_slave_node_matches(struct device_node *np,
 652                int link, uint8_t id)
 653{
 654        unsigned int len, na, ns;
 655        const __be32 *prop;
 656
 657        na = of_n_addr_cells(np);
 658        ns = of_n_size_cells(np);
 659
 660        /* Ensure we have the correct format for addresses and sizes in
 661         * reg properties
 662         */
 663        if (na != 2 || ns != 0)
 664                return false;
 665
 666        prop = of_get_property(np, "reg", &len);
 667        if (!prop || len != 8)
 668                return false;
 669
 670        return (of_read_number(prop, 1) == link) &&
 671                (of_read_number(prop + 1, 1) == id);
 672}
 673
 674/* Find a matching node for the slave at (link, id). Returns NULL if none
 675 * found, or a matching node with refcount already incremented.
 676 */
 677static struct device_node *fsi_slave_find_of_node(struct fsi_master *master,
 678                int link, uint8_t id)
 679{
 680        struct device_node *parent, *np;
 681
 682        parent = dev_of_node(&master->dev);
 683        if (!parent)
 684                return NULL;
 685
 686        for_each_child_of_node(parent, np) {
 687                if (fsi_slave_node_matches(np, link, id))
 688                        return np;
 689        }
 690
 691        return NULL;
 692}
 693
 694static ssize_t cfam_read(struct file *filep, char __user *buf, size_t count,
 695                         loff_t *offset)
 696{
 697        struct fsi_slave *slave = filep->private_data;
 698        size_t total_len, read_len;
 699        loff_t off = *offset;
 700        ssize_t rc;
 701
 702        if (off < 0)
 703                return -EINVAL;
 704
 705        if (off > 0xffffffff || count > 0xffffffff || off + count > 0xffffffff)
 706                return -EINVAL;
 707
 708        for (total_len = 0; total_len < count; total_len += read_len) {
 709                __be32 data;
 710
 711                read_len = min_t(size_t, count, 4);
 712                read_len -= off & 0x3;
 713
 714                rc = fsi_slave_read(slave, off, &data, read_len);
 715                if (rc)
 716                        goto fail;
 717                rc = copy_to_user(buf + total_len, &data, read_len);
 718                if (rc) {
 719                        rc = -EFAULT;
 720                        goto fail;
 721                }
 722                off += read_len;
 723        }
 724        rc = count;
 725 fail:
 726        *offset = off;
 727        return rc;
 728}
 729
 730static ssize_t cfam_write(struct file *filep, const char __user *buf,
 731                          size_t count, loff_t *offset)
 732{
 733        struct fsi_slave *slave = filep->private_data;
 734        size_t total_len, write_len;
 735        loff_t off = *offset;
 736        ssize_t rc;
 737
 738
 739        if (off < 0)
 740                return -EINVAL;
 741
 742        if (off > 0xffffffff || count > 0xffffffff || off + count > 0xffffffff)
 743                return -EINVAL;
 744
 745        for (total_len = 0; total_len < count; total_len += write_len) {
 746                __be32 data;
 747
 748                write_len = min_t(size_t, count, 4);
 749                write_len -= off & 0x3;
 750
 751                rc = copy_from_user(&data, buf + total_len, write_len);
 752                if (rc) {
 753                        rc = -EFAULT;
 754                        goto fail;
 755                }
 756                rc = fsi_slave_write(slave, off, &data, write_len);
 757                if (rc)
 758                        goto fail;
 759                off += write_len;
 760        }
 761        rc = count;
 762 fail:
 763        *offset = off;
 764        return rc;
 765}
 766
 767static loff_t cfam_llseek(struct file *file, loff_t offset, int whence)
 768{
 769        switch (whence) {
 770        case SEEK_CUR:
 771                break;
 772        case SEEK_SET:
 773                file->f_pos = offset;
 774                break;
 775        default:
 776                return -EINVAL;
 777        }
 778
 779        return offset;
 780}
 781
 782static int cfam_open(struct inode *inode, struct file *file)
 783{
 784        struct fsi_slave *slave = container_of(inode->i_cdev, struct fsi_slave, cdev);
 785
 786        file->private_data = slave;
 787
 788        return 0;
 789}
 790
 791static const struct file_operations cfam_fops = {
 792        .owner          = THIS_MODULE,
 793        .open           = cfam_open,
 794        .llseek         = cfam_llseek,
 795        .read           = cfam_read,
 796        .write          = cfam_write,
 797};
 798
 799static ssize_t send_term_store(struct device *dev,
 800                               struct device_attribute *attr,
 801                               const char *buf, size_t count)
 802{
 803        struct fsi_slave *slave = to_fsi_slave(dev);
 804        struct fsi_master *master = slave->master;
 805
 806        if (!master->term)
 807                return -ENODEV;
 808
 809        master->term(master, slave->link, slave->id);
 810        return count;
 811}
 812
 813static DEVICE_ATTR_WO(send_term);
 814
 815static ssize_t slave_send_echo_show(struct device *dev,
 816                                    struct device_attribute *attr,
 817                                    char *buf)
 818{
 819        struct fsi_slave *slave = to_fsi_slave(dev);
 820
 821        return sprintf(buf, "%u\n", slave->t_send_delay);
 822}
 823
 824static ssize_t slave_send_echo_store(struct device *dev,
 825                struct device_attribute *attr, const char *buf, size_t count)
 826{
 827        struct fsi_slave *slave = to_fsi_slave(dev);
 828        struct fsi_master *master = slave->master;
 829        unsigned long val;
 830        int rc;
 831
 832        if (kstrtoul(buf, 0, &val) < 0)
 833                return -EINVAL;
 834
 835        if (val < 1 || val > 16)
 836                return -EINVAL;
 837
 838        if (!master->link_config)
 839                return -ENXIO;
 840
 841        /* Current HW mandates that send and echo delay are identical */
 842        slave->t_send_delay = val;
 843        slave->t_echo_delay = val;
 844
 845        rc = fsi_slave_set_smode(slave);
 846        if (rc < 0)
 847                return rc;
 848        if (master->link_config)
 849                master->link_config(master, slave->link,
 850                                    slave->t_send_delay,
 851                                    slave->t_echo_delay);
 852
 853        return count;
 854}
 855
 856static DEVICE_ATTR(send_echo_delays, 0600,
 857                   slave_send_echo_show, slave_send_echo_store);
 858
 859static ssize_t chip_id_show(struct device *dev,
 860                            struct device_attribute *attr,
 861                            char *buf)
 862{
 863        struct fsi_slave *slave = to_fsi_slave(dev);
 864
 865        return sprintf(buf, "%d\n", slave->chip_id);
 866}
 867
 868static DEVICE_ATTR_RO(chip_id);
 869
 870static ssize_t cfam_id_show(struct device *dev,
 871                            struct device_attribute *attr,
 872                            char *buf)
 873{
 874        struct fsi_slave *slave = to_fsi_slave(dev);
 875
 876        return sprintf(buf, "0x%x\n", slave->cfam_id);
 877}
 878
 879static DEVICE_ATTR_RO(cfam_id);
 880
 881static struct attribute *cfam_attr[] = {
 882        &dev_attr_send_echo_delays.attr,
 883        &dev_attr_chip_id.attr,
 884        &dev_attr_cfam_id.attr,
 885        &dev_attr_send_term.attr,
 886        NULL,
 887};
 888
 889static const struct attribute_group cfam_attr_group = {
 890        .attrs = cfam_attr,
 891};
 892
 893static const struct attribute_group *cfam_attr_groups[] = {
 894        &cfam_attr_group,
 895        NULL,
 896};
 897
 898static char *cfam_devnode(struct device *dev, umode_t *mode,
 899                          kuid_t *uid, kgid_t *gid)
 900{
 901        struct fsi_slave *slave = to_fsi_slave(dev);
 902
 903#ifdef CONFIG_FSI_NEW_DEV_NODE
 904        return kasprintf(GFP_KERNEL, "fsi/cfam%d", slave->cdev_idx);
 905#else
 906        return kasprintf(GFP_KERNEL, "cfam%d", slave->cdev_idx);
 907#endif
 908}
 909
 910static const struct device_type cfam_type = {
 911        .name = "cfam",
 912        .devnode = cfam_devnode,
 913        .groups = cfam_attr_groups
 914};
 915
 916static char *fsi_cdev_devnode(struct device *dev, umode_t *mode,
 917                              kuid_t *uid, kgid_t *gid)
 918{
 919#ifdef CONFIG_FSI_NEW_DEV_NODE
 920        return kasprintf(GFP_KERNEL, "fsi/%s", dev_name(dev));
 921#else
 922        return kasprintf(GFP_KERNEL, "%s", dev_name(dev));
 923#endif
 924}
 925
 926const struct device_type fsi_cdev_type = {
 927        .name = "fsi-cdev",
 928        .devnode = fsi_cdev_devnode,
 929};
 930EXPORT_SYMBOL_GPL(fsi_cdev_type);
 931
 932/* Backward compatible /dev/ numbering in "old style" mode */
 933static int fsi_adjust_index(int index)
 934{
 935#ifdef CONFIG_FSI_NEW_DEV_NODE
 936        return index;
 937#else
 938        return index + 1;
 939#endif
 940}
 941
 942static int __fsi_get_new_minor(struct fsi_slave *slave, enum fsi_dev_type type,
 943                               dev_t *out_dev, int *out_index)
 944{
 945        int cid = slave->chip_id;
 946        int id;
 947
 948        /* Check if we qualify for legacy numbering */
 949        if (cid >= 0 && cid < 16 && type < 4) {
 950                /* Try reserving the legacy number */
 951                id = (cid << 4) | type;
 952                id = ida_simple_get(&fsi_minor_ida, id, id + 1, GFP_KERNEL);
 953                if (id >= 0) {
 954                        *out_index = fsi_adjust_index(cid);
 955                        *out_dev = fsi_base_dev + id;
 956                        return 0;
 957                }
 958                /* Other failure */
 959                if (id != -ENOSPC)
 960                        return id;
 961                /* Fallback to non-legacy allocation */
 962        }
 963        id = ida_simple_get(&fsi_minor_ida, FSI_CHAR_LEGACY_TOP,
 964                            FSI_CHAR_MAX_DEVICES, GFP_KERNEL);
 965        if (id < 0)
 966                return id;
 967        *out_index = fsi_adjust_index(id);
 968        *out_dev = fsi_base_dev + id;
 969        return 0;
 970}
 971
 972int fsi_get_new_minor(struct fsi_device *fdev, enum fsi_dev_type type,
 973                      dev_t *out_dev, int *out_index)
 974{
 975        return __fsi_get_new_minor(fdev->slave, type, out_dev, out_index);
 976}
 977EXPORT_SYMBOL_GPL(fsi_get_new_minor);
 978
 979void fsi_free_minor(dev_t dev)
 980{
 981        ida_simple_remove(&fsi_minor_ida, MINOR(dev));
 982}
 983EXPORT_SYMBOL_GPL(fsi_free_minor);
 984
 985static int fsi_slave_init(struct fsi_master *master, int link, uint8_t id)
 986{
 987        uint32_t cfam_id;
 988        struct fsi_slave *slave;
 989        uint8_t crc;
 990        __be32 data, llmode, slbus;
 991        int rc;
 992
 993        /* Currently, we only support single slaves on a link, and use the
 994         * full 23-bit address range
 995         */
 996        if (id != 0)
 997                return -EINVAL;
 998
 999        rc = fsi_master_read(master, link, id, 0, &data, sizeof(data));
1000        if (rc) {
1001                dev_dbg(&master->dev, "can't read slave %02x:%02x %d\n",
1002                                link, id, rc);
1003                return -ENODEV;
1004        }
1005        cfam_id = be32_to_cpu(data);
1006
1007        crc = crc4(0, cfam_id, 32);
1008        if (crc) {
1009                dev_warn(&master->dev, "slave %02x:%02x invalid cfam id CRC!\n",
1010                                link, id);
1011                return -EIO;
1012        }
1013
1014        dev_dbg(&master->dev, "fsi: found chip %08x at %02x:%02x:%02x\n",
1015                        cfam_id, master->idx, link, id);
1016
1017        /* If we're behind a master that doesn't provide a self-running bus
1018         * clock, put the slave into async mode
1019         */
1020        if (master->flags & FSI_MASTER_FLAG_SWCLOCK) {
1021                llmode = cpu_to_be32(FSI_LLMODE_ASYNC);
1022                rc = fsi_master_write(master, link, id,
1023                                FSI_SLAVE_BASE + FSI_LLMODE,
1024                                &llmode, sizeof(llmode));
1025                if (rc)
1026                        dev_warn(&master->dev,
1027                                "can't set llmode on slave:%02x:%02x %d\n",
1028                                link, id, rc);
1029        }
1030
1031        /* We can communicate with a slave; create the slave device and
1032         * register.
1033         */
1034        slave = kzalloc(sizeof(*slave), GFP_KERNEL);
1035        if (!slave)
1036                return -ENOMEM;
1037
1038        dev_set_name(&slave->dev, "slave@%02x:%02x", link, id);
1039        slave->dev.type = &cfam_type;
1040        slave->dev.parent = &master->dev;
1041        slave->dev.of_node = fsi_slave_find_of_node(master, link, id);
1042        slave->dev.release = fsi_slave_release;
1043        device_initialize(&slave->dev);
1044        slave->cfam_id = cfam_id;
1045        slave->master = master;
1046        slave->link = link;
1047        slave->id = id;
1048        slave->size = FSI_SLAVE_SIZE_23b;
1049        slave->t_send_delay = 16;
1050        slave->t_echo_delay = 16;
1051
1052        /* Get chip ID if any */
1053        slave->chip_id = -1;
1054        if (slave->dev.of_node) {
1055                uint32_t prop;
1056                if (!of_property_read_u32(slave->dev.of_node, "chip-id", &prop))
1057                        slave->chip_id = prop;
1058
1059        }
1060
1061        slbus = cpu_to_be32(FSI_SLBUS_FORCE);
1062        rc = fsi_master_write(master, link, id, FSI_SLAVE_BASE + FSI_SLBUS,
1063                              &slbus, sizeof(slbus));
1064        if (rc)
1065                dev_warn(&master->dev,
1066                         "can't set slbus on slave:%02x:%02x %d\n", link, id,
1067                         rc);
1068
1069        rc = fsi_slave_set_smode(slave);
1070        if (rc) {
1071                dev_warn(&master->dev,
1072                                "can't set smode on slave:%02x:%02x %d\n",
1073                                link, id, rc);
1074                goto err_free;
1075        }
1076
1077        /* Allocate a minor in the FSI space */
1078        rc = __fsi_get_new_minor(slave, fsi_dev_cfam, &slave->dev.devt,
1079                                 &slave->cdev_idx);
1080        if (rc)
1081                goto err_free;
1082
1083        /* Create chardev for userspace access */
1084        cdev_init(&slave->cdev, &cfam_fops);
1085        rc = cdev_device_add(&slave->cdev, &slave->dev);
1086        if (rc) {
1087                dev_err(&slave->dev, "Error %d creating slave device\n", rc);
1088                goto err_free_ida;
1089        }
1090
1091        /* Now that we have the cdev registered with the core, any fatal
1092         * failures beyond this point will need to clean up through
1093         * cdev_device_del(). Fortunately though, nothing past here is fatal.
1094         */
1095
1096        if (master->link_config)
1097                master->link_config(master, link,
1098                                    slave->t_send_delay,
1099                                    slave->t_echo_delay);
1100
1101        /* Legacy raw file -> to be removed */
1102        rc = device_create_bin_file(&slave->dev, &fsi_slave_raw_attr);
1103        if (rc)
1104                dev_warn(&slave->dev, "failed to create raw attr: %d\n", rc);
1105
1106
1107        rc = fsi_slave_scan(slave);
1108        if (rc)
1109                dev_dbg(&master->dev, "failed during slave scan with: %d\n",
1110                                rc);
1111
1112        return 0;
1113
1114err_free_ida:
1115        fsi_free_minor(slave->dev.devt);
1116err_free:
1117        of_node_put(slave->dev.of_node);
1118        kfree(slave);
1119        return rc;
1120}
1121
1122/* FSI master support */
1123static int fsi_check_access(uint32_t addr, size_t size)
1124{
1125        if (size == 4) {
1126                if (addr & 0x3)
1127                        return -EINVAL;
1128        } else if (size == 2) {
1129                if (addr & 0x1)
1130                        return -EINVAL;
1131        } else if (size != 1)
1132                return -EINVAL;
1133
1134        return 0;
1135}
1136
1137static int fsi_master_read(struct fsi_master *master, int link,
1138                uint8_t slave_id, uint32_t addr, void *val, size_t size)
1139{
1140        int rc;
1141
1142        trace_fsi_master_read(master, link, slave_id, addr, size);
1143
1144        rc = fsi_check_access(addr, size);
1145        if (!rc)
1146                rc = master->read(master, link, slave_id, addr, val, size);
1147
1148        trace_fsi_master_rw_result(master, link, slave_id, addr, size,
1149                        false, val, rc);
1150
1151        return rc;
1152}
1153
1154static int fsi_master_write(struct fsi_master *master, int link,
1155                uint8_t slave_id, uint32_t addr, const void *val, size_t size)
1156{
1157        int rc;
1158
1159        trace_fsi_master_write(master, link, slave_id, addr, size, val);
1160
1161        rc = fsi_check_access(addr, size);
1162        if (!rc)
1163                rc = master->write(master, link, slave_id, addr, val, size);
1164
1165        trace_fsi_master_rw_result(master, link, slave_id, addr, size,
1166                        true, val, rc);
1167
1168        return rc;
1169}
1170
1171static int fsi_master_link_disable(struct fsi_master *master, int link)
1172{
1173        if (master->link_enable)
1174                return master->link_enable(master, link, false);
1175
1176        return 0;
1177}
1178
1179static int fsi_master_link_enable(struct fsi_master *master, int link)
1180{
1181        if (master->link_enable)
1182                return master->link_enable(master, link, true);
1183
1184        return 0;
1185}
1186
1187/*
1188 * Issue a break command on this link
1189 */
1190static int fsi_master_break(struct fsi_master *master, int link)
1191{
1192        int rc = 0;
1193
1194        trace_fsi_master_break(master, link);
1195
1196        if (master->send_break)
1197                rc = master->send_break(master, link);
1198        if (master->link_config)
1199                master->link_config(master, link, 16, 16);
1200
1201        return rc;
1202}
1203
1204static int fsi_master_scan(struct fsi_master *master)
1205{
1206        int link, rc;
1207
1208        for (link = 0; link < master->n_links; link++) {
1209                rc = fsi_master_link_enable(master, link);
1210                if (rc) {
1211                        dev_dbg(&master->dev,
1212                                "enable link %d failed: %d\n", link, rc);
1213                        continue;
1214                }
1215                rc = fsi_master_break(master, link);
1216                if (rc) {
1217                        fsi_master_link_disable(master, link);
1218                        dev_dbg(&master->dev,
1219                                "break to link %d failed: %d\n", link, rc);
1220                        continue;
1221                }
1222
1223                rc = fsi_slave_init(master, link, 0);
1224                if (rc)
1225                        fsi_master_link_disable(master, link);
1226        }
1227
1228        return 0;
1229}
1230
1231static int fsi_slave_remove_device(struct device *dev, void *arg)
1232{
1233        device_unregister(dev);
1234        return 0;
1235}
1236
1237static int fsi_master_remove_slave(struct device *dev, void *arg)
1238{
1239        struct fsi_slave *slave = to_fsi_slave(dev);
1240
1241        device_for_each_child(dev, NULL, fsi_slave_remove_device);
1242        cdev_device_del(&slave->cdev, &slave->dev);
1243        put_device(dev);
1244        return 0;
1245}
1246
1247static void fsi_master_unscan(struct fsi_master *master)
1248{
1249        device_for_each_child(&master->dev, NULL, fsi_master_remove_slave);
1250}
1251
1252int fsi_master_rescan(struct fsi_master *master)
1253{
1254        int rc;
1255
1256        mutex_lock(&master->scan_lock);
1257        fsi_master_unscan(master);
1258        rc = fsi_master_scan(master);
1259        mutex_unlock(&master->scan_lock);
1260
1261        return rc;
1262}
1263EXPORT_SYMBOL_GPL(fsi_master_rescan);
1264
1265static ssize_t master_rescan_store(struct device *dev,
1266                struct device_attribute *attr, const char *buf, size_t count)
1267{
1268        struct fsi_master *master = to_fsi_master(dev);
1269        int rc;
1270
1271        rc = fsi_master_rescan(master);
1272        if (rc < 0)
1273                return rc;
1274
1275        return count;
1276}
1277
1278static DEVICE_ATTR(rescan, 0200, NULL, master_rescan_store);
1279
1280static ssize_t master_break_store(struct device *dev,
1281                struct device_attribute *attr, const char *buf, size_t count)
1282{
1283        struct fsi_master *master = to_fsi_master(dev);
1284
1285        fsi_master_break(master, 0);
1286
1287        return count;
1288}
1289
1290static DEVICE_ATTR(break, 0200, NULL, master_break_store);
1291
1292static struct attribute *master_attrs[] = {
1293        &dev_attr_break.attr,
1294        &dev_attr_rescan.attr,
1295        NULL
1296};
1297
1298ATTRIBUTE_GROUPS(master);
1299
1300static struct class fsi_master_class = {
1301        .name = "fsi-master",
1302        .dev_groups = master_groups,
1303};
1304
1305int fsi_master_register(struct fsi_master *master)
1306{
1307        int rc;
1308        struct device_node *np;
1309
1310        mutex_init(&master->scan_lock);
1311        master->idx = ida_simple_get(&master_ida, 0, INT_MAX, GFP_KERNEL);
1312        dev_set_name(&master->dev, "fsi%d", master->idx);
1313        master->dev.class = &fsi_master_class;
1314
1315        rc = device_register(&master->dev);
1316        if (rc) {
1317                ida_simple_remove(&master_ida, master->idx);
1318                return rc;
1319        }
1320
1321        np = dev_of_node(&master->dev);
1322        if (!of_property_read_bool(np, "no-scan-on-init")) {
1323                mutex_lock(&master->scan_lock);
1324                fsi_master_scan(master);
1325                mutex_unlock(&master->scan_lock);
1326        }
1327
1328        return 0;
1329}
1330EXPORT_SYMBOL_GPL(fsi_master_register);
1331
1332void fsi_master_unregister(struct fsi_master *master)
1333{
1334        if (master->idx >= 0) {
1335                ida_simple_remove(&master_ida, master->idx);
1336                master->idx = -1;
1337        }
1338
1339        mutex_lock(&master->scan_lock);
1340        fsi_master_unscan(master);
1341        mutex_unlock(&master->scan_lock);
1342        device_unregister(&master->dev);
1343}
1344EXPORT_SYMBOL_GPL(fsi_master_unregister);
1345
1346/* FSI core & Linux bus type definitions */
1347
1348static int fsi_bus_match(struct device *dev, struct device_driver *drv)
1349{
1350        struct fsi_device *fsi_dev = to_fsi_dev(dev);
1351        struct fsi_driver *fsi_drv = to_fsi_drv(drv);
1352        const struct fsi_device_id *id;
1353
1354        if (!fsi_drv->id_table)
1355                return 0;
1356
1357        for (id = fsi_drv->id_table; id->engine_type; id++) {
1358                if (id->engine_type != fsi_dev->engine_type)
1359                        continue;
1360                if (id->version == FSI_VERSION_ANY ||
1361                                id->version == fsi_dev->version)
1362                        return 1;
1363        }
1364
1365        return 0;
1366}
1367
1368int fsi_driver_register(struct fsi_driver *fsi_drv)
1369{
1370        if (!fsi_drv)
1371                return -EINVAL;
1372        if (!fsi_drv->id_table)
1373                return -EINVAL;
1374
1375        return driver_register(&fsi_drv->drv);
1376}
1377EXPORT_SYMBOL_GPL(fsi_driver_register);
1378
1379void fsi_driver_unregister(struct fsi_driver *fsi_drv)
1380{
1381        driver_unregister(&fsi_drv->drv);
1382}
1383EXPORT_SYMBOL_GPL(fsi_driver_unregister);
1384
1385struct bus_type fsi_bus_type = {
1386        .name           = "fsi",
1387        .match          = fsi_bus_match,
1388};
1389EXPORT_SYMBOL_GPL(fsi_bus_type);
1390
1391static int __init fsi_init(void)
1392{
1393        int rc;
1394
1395        rc = alloc_chrdev_region(&fsi_base_dev, 0, FSI_CHAR_MAX_DEVICES, "fsi");
1396        if (rc)
1397                return rc;
1398        rc = bus_register(&fsi_bus_type);
1399        if (rc)
1400                goto fail_bus;
1401
1402        rc = class_register(&fsi_master_class);
1403        if (rc)
1404                goto fail_class;
1405
1406        return 0;
1407
1408 fail_class:
1409        bus_unregister(&fsi_bus_type);
1410 fail_bus:
1411        unregister_chrdev_region(fsi_base_dev, FSI_CHAR_MAX_DEVICES);
1412        return rc;
1413}
1414postcore_initcall(fsi_init);
1415
1416static void fsi_exit(void)
1417{
1418        class_unregister(&fsi_master_class);
1419        bus_unregister(&fsi_bus_type);
1420        unregister_chrdev_region(fsi_base_dev, FSI_CHAR_MAX_DEVICES);
1421        ida_destroy(&fsi_minor_ida);
1422}
1423module_exit(fsi_exit);
1424module_param(discard_errors, int, 0664);
1425MODULE_LICENSE("GPL");
1426MODULE_PARM_DESC(discard_errors, "Don't invoke error handling on bus accesses");
1427