LXR linux/drivers/pci/vpd.c

   1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 * PCI VPD support
   4 *
   5 * Copyright (C) 2010 Broadcom Corporation.
   6 */
   7
   8#include <linux/pci.h>
   9#include <linux/delay.h>
  10#include <linux/export.h>
  11#include <linux/sched/signal.h>
  12#include <asm/unaligned.h>
  13#include "pci.h"
  14
  15#define PCI_VPD_LRDT_TAG_SIZE           3
  16#define PCI_VPD_SRDT_LEN_MASK           0x07
  17#define PCI_VPD_SRDT_TAG_SIZE           1
  18#define PCI_VPD_STIN_END                0x0f
  19#define PCI_VPD_INFO_FLD_HDR_SIZE       3
  20
  21static u16 pci_vpd_lrdt_size(const u8 *lrdt)
  22{
  23        return get_unaligned_le16(lrdt + 1);
  24}
  25
  26static u8 pci_vpd_srdt_tag(const u8 *srdt)
  27{
  28        return *srdt >> 3;
  29}
  30
  31static u8 pci_vpd_srdt_size(const u8 *srdt)
  32{
  33        return *srdt & PCI_VPD_SRDT_LEN_MASK;
  34}
  35
  36static u8 pci_vpd_info_field_size(const u8 *info_field)
  37{
  38        return info_field[2];
  39}
  40
  41/* VPD access through PCI 2.2+ VPD capability */
  42
  43static struct pci_dev *pci_get_func0_dev(struct pci_dev *dev)
  44{
  45        return pci_get_slot(dev->bus, PCI_DEVFN(PCI_SLOT(dev->devfn), 0));
  46}
  47
  48#define PCI_VPD_MAX_SIZE        (PCI_VPD_ADDR_MASK + 1)
  49#define PCI_VPD_SZ_INVALID      UINT_MAX
  50
  51/**
  52 * pci_vpd_size - determine actual size of Vital Product Data
  53 * @dev:        pci device struct
  54 */
  55static size_t pci_vpd_size(struct pci_dev *dev)
  56{
  57        size_t off = 0, size;
  58        unsigned char tag, header[1+2]; /* 1 byte tag, 2 bytes length */
  59
  60        /* Otherwise the following reads would fail. */
  61        dev->vpd.len = PCI_VPD_MAX_SIZE;
  62
  63        while (pci_read_vpd(dev, off, 1, header) == 1) {
  64                size = 0;
  65
  66                if (off == 0 && (header[0] == 0x00 || header[0] == 0xff))
  67                        goto error;
  68
  69                if (header[0] & PCI_VPD_LRDT) {
  70                        /* Large Resource Data Type Tag */
  71                        if (pci_read_vpd(dev, off + 1, 2, &header[1]) != 2) {
  72                                pci_warn(dev, "failed VPD read at offset %zu\n",
  73                                         off + 1);
  74                                return off ?: PCI_VPD_SZ_INVALID;
  75                        }
  76                        size = pci_vpd_lrdt_size(header);
  77                        if (off + size > PCI_VPD_MAX_SIZE)
  78                                goto error;
  79
  80                        off += PCI_VPD_LRDT_TAG_SIZE + size;
  81                } else {
  82                        /* Short Resource Data Type Tag */
  83                        tag = pci_vpd_srdt_tag(header);
  84                        size = pci_vpd_srdt_size(header);
  85                        if (off + size > PCI_VPD_MAX_SIZE)
  86                                goto error;
  87
  88                        off += PCI_VPD_SRDT_TAG_SIZE + size;
  89                        if (tag == PCI_VPD_STIN_END)    /* End tag descriptor */
  90                                return off;
  91                }
  92        }
  93        return off;
  94
  95error:
  96        pci_info(dev, "invalid VPD tag %#04x (size %zu) at offset %zu%s\n",
  97                 header[0], size, off, off == 0 ?
  98                 "; assume missing optional EEPROM" : "");
  99        return off ?: PCI_VPD_SZ_INVALID;
 100}
 101
 102static bool pci_vpd_available(struct pci_dev *dev)
 103{
 104        struct pci_vpd *vpd = &dev->vpd;
 105
 106        if (!vpd->cap)
 107                return false;
 108
 109        if (vpd->len == 0) {
 110                vpd->len = pci_vpd_size(dev);
 111                if (vpd->len == PCI_VPD_SZ_INVALID) {
 112                        vpd->cap = 0;
 113                        return false;
 114                }
 115        }
 116
 117        return true;
 118}
 119
 120/*
 121 * Wait for last operation to complete.
 122 * This code has to spin since there is no other notification from the PCI
 123 * hardware. Since the VPD is often implemented by serial attachment to an
 124 * EEPROM, it may take many milliseconds to complete.
 125 * @set: if true wait for flag to be set, else wait for it to be cleared
 126 *
 127 * Returns 0 on success, negative values indicate error.
 128 */
 129static int pci_vpd_wait(struct pci_dev *dev, bool set)
 130{
 131        struct pci_vpd *vpd = &dev->vpd;
 132        unsigned long timeout = jiffies + msecs_to_jiffies(125);
 133        unsigned long max_sleep = 16;
 134        u16 status;
 135        int ret;
 136
 137        do {
 138                ret = pci_user_read_config_word(dev, vpd->cap + PCI_VPD_ADDR,
 139                                                &status);
 140                if (ret < 0)
 141                        return ret;
 142
 143                if (!!(status & PCI_VPD_ADDR_F) == set)
 144                        return 0;
 145
 146                if (time_after(jiffies, timeout))
 147                        break;
 148
 149                usleep_range(10, max_sleep);
 150                if (max_sleep < 1024)
 151                        max_sleep *= 2;
 152        } while (true);
 153
 154        pci_warn(dev, "VPD access failed.  This is likely a firmware bug on this device.  Contact the card vendor for a firmware update\n");
 155        return -ETIMEDOUT;
 156}
 157
 158static ssize_t pci_vpd_read(struct pci_dev *dev, loff_t pos, size_t count,
 159                            void *arg)
 160{
 161        struct pci_vpd *vpd = &dev->vpd;
 162        int ret = 0;
 163        loff_t end = pos + count;
 164        u8 *buf = arg;
 165
 166        if (!pci_vpd_available(dev))
 167                return -ENODEV;
 168
 169        if (pos < 0)
 170                return -EINVAL;
 171
 172        if (pos > vpd->len)
 173                return 0;
 174
 175        if (end > vpd->len) {
 176                end = vpd->len;
 177                count = end - pos;
 178        }
 179
 180        if (mutex_lock_killable(&vpd->lock))
 181                return -EINTR;
 182
 183        while (pos < end) {
 184                u32 val;
 185                unsigned int i, skip;
 186
 187                if (fatal_signal_pending(current)) {
 188                        ret = -EINTR;
 189                        break;
 190                }
 191
 192                ret = pci_user_write_config_word(dev, vpd->cap + PCI_VPD_ADDR,
 193                                                 pos & ~3);
 194                if (ret < 0)
 195                        break;
 196                ret = pci_vpd_wait(dev, true);
 197                if (ret < 0)
 198                        break;
 199
 200                ret = pci_user_read_config_dword(dev, vpd->cap + PCI_VPD_DATA, &val);
 201                if (ret < 0)
 202                        break;
 203
 204                skip = pos & 3;
 205                for (i = 0;  i < sizeof(u32); i++) {
 206                        if (i >= skip) {
 207                                *buf++ = val;
 208                                if (++pos == end)
 209                                        break;
 210                        }
 211                        val >>= 8;
 212                }
 213        }
 214
 215        mutex_unlock(&vpd->lock);
 216        return ret ? ret : count;
 217}
 218
 219static ssize_t pci_vpd_write(struct pci_dev *dev, loff_t pos, size_t count,
 220                             const void *arg)
 221{
 222        struct pci_vpd *vpd = &dev->vpd;
 223        const u8 *buf = arg;
 224        loff_t end = pos + count;
 225        int ret = 0;
 226
 227        if (!pci_vpd_available(dev))
 228                return -ENODEV;
 229
 230        if (pos < 0 || (pos & 3) || (count & 3))
 231                return -EINVAL;
 232
 233        if (end > vpd->len)
 234                return -EINVAL;
 235
 236        if (mutex_lock_killable(&vpd->lock))
 237                return -EINTR;
 238
 239        while (pos < end) {
 240                ret = pci_user_write_config_dword(dev, vpd->cap + PCI_VPD_DATA,
 241                                                  get_unaligned_le32(buf));
 242                if (ret < 0)
 243                        break;
 244                ret = pci_user_write_config_word(dev, vpd->cap + PCI_VPD_ADDR,
 245                                                 pos | PCI_VPD_ADDR_F);
 246                if (ret < 0)
 247                        break;
 248
 249                ret = pci_vpd_wait(dev, false);
 250                if (ret < 0)
 251                        break;
 252
 253                buf += sizeof(u32);
 254                pos += sizeof(u32);
 255        }
 256
 257        mutex_unlock(&vpd->lock);
 258        return ret ? ret : count;
 259}
 260
 261void pci_vpd_init(struct pci_dev *dev)
 262{
 263        if (dev->vpd.len == PCI_VPD_SZ_INVALID)
 264                return;
 265
 266        dev->vpd.cap = pci_find_capability(dev, PCI_CAP_ID_VPD);
 267        mutex_init(&dev->vpd.lock);
 268}
 269
 270static ssize_t vpd_read(struct file *filp, struct kobject *kobj,
 271                        struct bin_attribute *bin_attr, char *buf, loff_t off,
 272                        size_t count)
 273{
 274        struct pci_dev *dev = to_pci_dev(kobj_to_dev(kobj));
 275
 276        return pci_read_vpd(dev, off, count, buf);
 277}
 278
 279static ssize_t vpd_write(struct file *filp, struct kobject *kobj,
 280                         struct bin_attribute *bin_attr, char *buf, loff_t off,
 281                         size_t count)
 282{
 283        struct pci_dev *dev = to_pci_dev(kobj_to_dev(kobj));
 284
 285        return pci_write_vpd(dev, off, count, buf);
 286}
 287static BIN_ATTR(vpd, 0600, vpd_read, vpd_write, 0);
 288
 289static struct bin_attribute *vpd_attrs[] = {
 290        &bin_attr_vpd,
 291        NULL,
 292};
 293
 294static umode_t vpd_attr_is_visible(struct kobject *kobj,
 295                                   struct bin_attribute *a, int n)
 296{
 297        struct pci_dev *pdev = to_pci_dev(kobj_to_dev(kobj));
 298
 299        if (!pdev->vpd.cap)
 300                return 0;
 301
 302        return a->attr.mode;
 303}
 304
 305const struct attribute_group pci_dev_vpd_attr_group = {
 306        .bin_attrs = vpd_attrs,
 307        .is_bin_visible = vpd_attr_is_visible,
 308};
 309
 310void *pci_vpd_alloc(struct pci_dev *dev, unsigned int *size)
 311{
 312        unsigned int len;
 313        void *buf;
 314        int cnt;
 315
 316        if (!pci_vpd_available(dev))
 317                return ERR_PTR(-ENODEV);
 318
 319        len = dev->vpd.len;
 320        buf = kmalloc(len, GFP_KERNEL);
 321        if (!buf)
 322                return ERR_PTR(-ENOMEM);
 323
 324        cnt = pci_read_vpd(dev, 0, len, buf);
 325        if (cnt != len) {
 326                kfree(buf);
 327                return ERR_PTR(-EIO);
 328        }
 329
 330        if (size)
 331                *size = len;
 332
 333        return buf;
 334}
 335EXPORT_SYMBOL_GPL(pci_vpd_alloc);
 336
 337static int pci_vpd_find_tag(const u8 *buf, unsigned int len, u8 rdt, unsigned int *size)
 338{
 339        int i = 0;
 340
 341        /* look for LRDT tags only, end tag is the only SRDT tag */
 342        while (i + PCI_VPD_LRDT_TAG_SIZE <= len && buf[i] & PCI_VPD_LRDT) {
 343                unsigned int lrdt_len = pci_vpd_lrdt_size(buf + i);
 344                u8 tag = buf[i];
 345
 346                i += PCI_VPD_LRDT_TAG_SIZE;
 347                if (tag == rdt) {
 348                        if (i + lrdt_len > len)
 349                                lrdt_len = len - i;
 350                        if (size)
 351                                *size = lrdt_len;
 352                        return i;
 353                }
 354
 355                i += lrdt_len;
 356        }
 357
 358        return -ENOENT;
 359}
 360
 361int pci_vpd_find_id_string(const u8 *buf, unsigned int len, unsigned int *size)
 362{
 363        return pci_vpd_find_tag(buf, len, PCI_VPD_LRDT_ID_STRING, size);
 364}
 365EXPORT_SYMBOL_GPL(pci_vpd_find_id_string);
 366
 367static int pci_vpd_find_info_keyword(const u8 *buf, unsigned int off,
 368                              unsigned int len, const char *kw)
 369{
 370        int i;
 371
 372        for (i = off; i + PCI_VPD_INFO_FLD_HDR_SIZE <= off + len;) {
 373                if (buf[i + 0] == kw[0] &&
 374                    buf[i + 1] == kw[1])
 375                        return i;
 376
 377                i += PCI_VPD_INFO_FLD_HDR_SIZE +
 378                     pci_vpd_info_field_size(&buf[i]);
 379        }
 380
 381        return -ENOENT;
 382}
 383
 384/**
 385 * pci_read_vpd - Read one entry from Vital Product Data
 386 * @dev:        PCI device struct
 387 * @pos:        offset in VPD space
 388 * @count:      number of bytes to read
 389 * @buf:        pointer to where to store result
 390 */
 391ssize_t pci_read_vpd(struct pci_dev *dev, loff_t pos, size_t count, void *buf)
 392{
 393        ssize_t ret;
 394
 395        if (dev->dev_flags & PCI_DEV_FLAGS_VPD_REF_F0) {
 396                dev = pci_get_func0_dev(dev);
 397                if (!dev)
 398                        return -ENODEV;
 399
 400                ret = pci_vpd_read(dev, pos, count, buf);
 401                pci_dev_put(dev);
 402                return ret;
 403        }
 404
 405        return pci_vpd_read(dev, pos, count, buf);
 406}
 407EXPORT_SYMBOL(pci_read_vpd);
 408
 409/**
 410 * pci_write_vpd - Write entry to Vital Product Data
 411 * @dev:        PCI device struct
 412 * @pos:        offset in VPD space
 413 * @count:      number of bytes to write
 414 * @buf:        buffer containing write data
 415 */
 416ssize_t pci_write_vpd(struct pci_dev *dev, loff_t pos, size_t count, const void *buf)
 417{
 418        ssize_t ret;
 419
 420        if (dev->dev_flags & PCI_DEV_FLAGS_VPD_REF_F0) {
 421                dev = pci_get_func0_dev(dev);
 422                if (!dev)
 423                        return -ENODEV;
 424
 425                ret = pci_vpd_write(dev, pos, count, buf);
 426                pci_dev_put(dev);
 427                return ret;
 428        }
 429
 430        return pci_vpd_write(dev, pos, count, buf);
 431}
 432EXPORT_SYMBOL(pci_write_vpd);
 433
 434int pci_vpd_find_ro_info_keyword(const void *buf, unsigned int len,
 435                                 const char *kw, unsigned int *size)
 436{
 437        int ro_start, infokw_start;
 438        unsigned int ro_len, infokw_size;
 439
 440        ro_start = pci_vpd_find_tag(buf, len, PCI_VPD_LRDT_RO_DATA, &ro_len);
 441        if (ro_start < 0)
 442                return ro_start;
 443
 444        infokw_start = pci_vpd_find_info_keyword(buf, ro_start, ro_len, kw);
 445        if (infokw_start < 0)
 446                return infokw_start;
 447
 448        infokw_size = pci_vpd_info_field_size(buf + infokw_start);
 449        infokw_start += PCI_VPD_INFO_FLD_HDR_SIZE;
 450
 451        if (infokw_start + infokw_size > len)
 452                return -EINVAL;
 453
 454        if (size)
 455                *size = infokw_size;
 456
 457        return infokw_start;
 458}
 459EXPORT_SYMBOL_GPL(pci_vpd_find_ro_info_keyword);
 460
 461int pci_vpd_check_csum(const void *buf, unsigned int len)
 462{
 463        const u8 *vpd = buf;
 464        unsigned int size;
 465        u8 csum = 0;
 466        int rv_start;
 467
 468        rv_start = pci_vpd_find_ro_info_keyword(buf, len, PCI_VPD_RO_KEYWORD_CHKSUM, &size);
 469        if (rv_start == -ENOENT) /* no checksum in VPD */
 470                return 1;
 471        else if (rv_start < 0)
 472                return rv_start;
 473
 474        if (!size)
 475                return -EINVAL;
 476
 477        while (rv_start >= 0)
 478                csum += vpd[rv_start--];
 479
 480        return csum ? -EILSEQ : 0;
 481}
 482EXPORT_SYMBOL_GPL(pci_vpd_check_csum);
 483
 484#ifdef CONFIG_PCI_QUIRKS
 485/*
 486 * Quirk non-zero PCI functions to route VPD access through function 0 for
 487 * devices that share VPD resources between functions.  The functions are
 488 * expected to be identical devices.
 489 */
 490static void quirk_f0_vpd_link(struct pci_dev *dev)
 491{
 492        struct pci_dev *f0;
 493
 494        if (!PCI_FUNC(dev->devfn))
 495                return;
 496
 497        f0 = pci_get_func0_dev(dev);
 498        if (!f0)
 499                return;
 500
 501        if (f0->vpd.cap && dev->class == f0->class &&
 502            dev->vendor == f0->vendor && dev->device == f0->device)
 503                dev->dev_flags |= PCI_DEV_FLAGS_VPD_REF_F0;
 504
 505        pci_dev_put(f0);
 506}
 507DECLARE_PCI_FIXUP_CLASS_EARLY(PCI_VENDOR_ID_INTEL, PCI_ANY_ID,
 508                              PCI_CLASS_NETWORK_ETHERNET, 8, quirk_f0_vpd_link);
 509
 510/*
 511 * If a device follows the VPD format spec, the PCI core will not read or
 512 * write past the VPD End Tag.  But some vendors do not follow the VPD
 513 * format spec, so we can't tell how much data is safe to access.  Devices
 514 * may behave unpredictably if we access too much.  Blacklist these devices
 515 * so we don't touch VPD at all.
 516 */
 517static void quirk_blacklist_vpd(struct pci_dev *dev)
 518{
 519        dev->vpd.len = PCI_VPD_SZ_INVALID;
 520        pci_warn(dev, FW_BUG "disabling VPD access (can't determine size of non-standard VPD format)\n");
 521}
 522DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_LSI_LOGIC, 0x0060, quirk_blacklist_vpd);
 523DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_LSI_LOGIC, 0x007c, quirk_blacklist_vpd);
 524DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_LSI_LOGIC, 0x0413, quirk_blacklist_vpd);
 525DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_LSI_LOGIC, 0x0078, quirk_blacklist_vpd);
 526DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_LSI_LOGIC, 0x0079, quirk_blacklist_vpd);
 527DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_LSI_LOGIC, 0x0073, quirk_blacklist_vpd);
 528DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_LSI_LOGIC, 0x0071, quirk_blacklist_vpd);
 529DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_LSI_LOGIC, 0x005b, quirk_blacklist_vpd);
 530DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_LSI_LOGIC, 0x002f, quirk_blacklist_vpd);
 531DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_LSI_LOGIC, 0x005d, quirk_blacklist_vpd);
 532DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_LSI_LOGIC, 0x005f, quirk_blacklist_vpd);
 533DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_ATTANSIC, PCI_ANY_ID, quirk_blacklist_vpd);
 534/*
 535 * The Amazon Annapurna Labs 0x0031 device id is reused for other non Root Port
 536 * device types, so the quirk is registered for the PCI_CLASS_BRIDGE_PCI class.
 537 */
 538DECLARE_PCI_FIXUP_CLASS_HEADER(PCI_VENDOR_ID_AMAZON_ANNAPURNA_LABS, 0x0031,
 539                               PCI_CLASS_BRIDGE_PCI, 8, quirk_blacklist_vpd);
 540
 541static void quirk_chelsio_extend_vpd(struct pci_dev *dev)
 542{
 543        int chip = (dev->device & 0xf000) >> 12;
 544        int func = (dev->device & 0x0f00) >>  8;
 545        int prod = (dev->device & 0x00ff) >>  0;
 546
 547        /*
 548         * If this is a T3-based adapter, there's a 1KB VPD area at offset
 549         * 0xc00 which contains the preferred VPD values.  If this is a T4 or
 550         * later based adapter, the special VPD is at offset 0x400 for the
 551         * Physical Functions (the SR-IOV Virtual Functions have no VPD
 552         * Capabilities).  The PCI VPD Access core routines will normally
 553         * compute the size of the VPD by parsing the VPD Data Structure at
 554         * offset 0x000.  This will result in silent failures when attempting
 555         * to accesses these other VPD areas which are beyond those computed
 556         * limits.
 557         */
 558        if (chip == 0x0 && prod >= 0x20)
 559                dev->vpd.len = 8192;
 560        else if (chip >= 0x4 && func < 0x8)
 561                dev->vpd.len = 2048;
 562}
 563
 564DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_CHELSIO, PCI_ANY_ID,
 565                         quirk_chelsio_extend_vpd);
 566
 567#endif
 568