1// SPDX-License-Identifier: GPL-2.0-only 2/* 3 * Interfaces to retrieve and set PDC Stable options (firmware) 4 * 5 * Copyright (C) 2005-2006 Thibaut VARENE <varenet@parisc-linux.org> 6 * 7 * DEV NOTE: the PDC Procedures reference states that: 8 * "A minimum of 96 bytes of Stable Storage is required. Providing more than 9 * 96 bytes of Stable Storage is optional [...]. Failure to provide the 10 * optional locations from 96 to 192 results in the loss of certain 11 * functionality during boot." 12 * 13 * Since locations between 96 and 192 are the various paths, most (if not 14 * all) PA-RISC machines should have them. Anyway, for safety reasons, the 15 * following code can deal with just 96 bytes of Stable Storage, and all 16 * sizes between 96 and 192 bytes (provided they are multiple of struct 17 * pdc_module_path size, eg: 128, 160 and 192) to provide full information. 18 * One last word: there's one path we can always count on: the primary path. 19 * Anything above 224 bytes is used for 'osdep2' OS-dependent storage area. 20 * 21 * The first OS-dependent area should always be available. Obviously, this is 22 * not true for the other one. Also bear in mind that reading/writing from/to 23 * osdep2 is much more expensive than from/to osdep1. 24 * NOTE: We do not handle the 2 bytes OS-dep area at 0x5D, nor the first 25 * 2 bytes of storage available right after OSID. That's a total of 4 bytes 26 * sacrificed: -ETOOLAZY :P 27 * 28 * The current policy wrt file permissions is: 29 * - write: root only 30 * - read: (reading triggers PDC calls) ? root only : everyone 31 * The rationale is that PDC calls could hog (DoS) the machine. 32 * 33 * TODO: 34 * - timer/fastsize write calls 35 */ 36 37#undef PDCS_DEBUG 38#ifdef PDCS_DEBUG 39#define DPRINTK(fmt, args...) printk(KERN_DEBUG fmt, ## args) 40#else 41#define DPRINTK(fmt, args...) 42#endif 43 44#include <linux/module.h> 45#include <linux/init.h> 46#include <linux/kernel.h> 47#include <linux/string.h> 48#include <linux/capability.h> 49#include <linux/ctype.h> 50#include <linux/sysfs.h> 51#include <linux/kobject.h> 52#include <linux/device.h> 53#include <linux/errno.h> 54#include <linux/spinlock.h> 55 56#include <asm/pdc.h> 57#include <asm/page.h> 58#include <linux/uaccess.h> 59#include <asm/hardware.h> 60 61#define PDCS_VERSION "0.30" 62#define PDCS_PREFIX "PDC Stable Storage" 63 64#define PDCS_ADDR_PPRI 0x00 65#define PDCS_ADDR_OSID 0x40 66#define PDCS_ADDR_OSD1 0x48 67#define PDCS_ADDR_DIAG 0x58 68#define PDCS_ADDR_FSIZ 0x5C 69#define PDCS_ADDR_PCON 0x60 70#define PDCS_ADDR_PALT 0x80 71#define PDCS_ADDR_PKBD 0xA0 72#define PDCS_ADDR_OSD2 0xE0 73 74MODULE_AUTHOR("Thibaut VARENE <varenet@parisc-linux.org>"); 75MODULE_DESCRIPTION("sysfs interface to HP PDC Stable Storage data"); 76MODULE_LICENSE("GPL"); 77MODULE_VERSION(PDCS_VERSION); 78 79/* holds Stable Storage size. Initialized once and for all, no lock needed */ 80static unsigned long pdcs_size __read_mostly; 81 82/* holds OS ID. Initialized once and for all, hopefully to 0x0006 */ 83static u16 pdcs_osid __read_mostly; 84 85/* This struct defines what we need to deal with a parisc pdc path entry */ 86struct pdcspath_entry { 87 rwlock_t rw_lock; /* to protect path entry access */ 88 short ready; /* entry record is valid if != 0 */ 89 unsigned long addr; /* entry address in stable storage */ 90 char *name; /* entry name */ 91 struct pdc_module_path devpath; /* device path in parisc representation */ 92 struct device *dev; /* corresponding device */ 93 struct kobject kobj; 94}; 95 96struct pdcspath_attribute { 97 struct attribute attr; 98 ssize_t (*show)(struct pdcspath_entry *entry, char *buf); 99 ssize_t (*store)(struct pdcspath_entry *entry, const char *buf, size_t count); 100}; 101 102#define PDCSPATH_ENTRY(_addr, _name) \ 103struct pdcspath_entry pdcspath_entry_##_name = { \ 104 .ready = 0, \ 105 .addr = _addr, \ 106 .name = __stringify(_name), \ 107}; 108 109#define PDCS_ATTR(_name, _mode, _show, _store) \ 110struct kobj_attribute pdcs_attr_##_name = { \ 111 .attr = {.name = __stringify(_name), .mode = _mode}, \ 112 .show = _show, \ 113 .store = _store, \ 114}; 115 116#define PATHS_ATTR(_name, _mode, _show, _store) \ 117struct pdcspath_attribute paths_attr_##_name = { \ 118 .attr = {.name = __stringify(_name), .mode = _mode}, \ 119 .show = _show, \ 120 .store = _store, \ 121}; 122 123#define to_pdcspath_attribute(_attr) container_of(_attr, struct pdcspath_attribute, attr) 124#define to_pdcspath_entry(obj) container_of(obj, struct pdcspath_entry, kobj) 125 126/** 127 * pdcspath_fetch - This function populates the path entry structs. 128 * @entry: A pointer to an allocated pdcspath_entry. 129 * 130 * The general idea is that you don't read from the Stable Storage every time 131 * you access the files provided by the facilities. We store a copy of the 132 * content of the stable storage WRT various paths in these structs. We read 133 * these structs when reading the files, and we will write to these structs when 134 * writing to the files, and only then write them back to the Stable Storage. 135 * 136 * This function expects to be called with @entry->rw_lock write-hold. 137 */ 138static int 139pdcspath_fetch(struct pdcspath_entry *entry) 140{ 141 struct pdc_module_path *devpath; 142 143 if (!entry) 144 return -EINVAL; 145 146 devpath = &entry->devpath; 147 148 DPRINTK("%s: fetch: 0x%p, 0x%p, addr: 0x%lx\n", __func__, 149 entry, devpath, entry->addr); 150 151 /* addr, devpath and count must be word aligned */ 152 if (pdc_stable_read(entry->addr, devpath, sizeof(*devpath)) != PDC_OK) 153 return -EIO; 154 155 /* Find the matching device. 156 NOTE: hardware_path overlays with pdc_module_path, so the nice cast can 157 be used */ 158 entry->dev = hwpath_to_device((struct hardware_path *)devpath); 159 160 entry->ready = 1; 161 162 DPRINTK("%s: device: 0x%p\n", __func__, entry->dev); 163 164 return 0; 165} 166 167/** 168 * pdcspath_store - This function writes a path to stable storage. 169 * @entry: A pointer to an allocated pdcspath_entry. 170 * 171 * It can be used in two ways: either by passing it a preset devpath struct 172 * containing an already computed hardware path, or by passing it a device 173 * pointer, from which it'll find out the corresponding hardware path. 174 * For now we do not handle the case where there's an error in writing to the 175 * Stable Storage area, so you'd better not mess up the data :P 176 * 177 * This function expects to be called with @entry->rw_lock write-hold. 178 */ 179static void 180pdcspath_store(struct pdcspath_entry *entry) 181{ 182 struct pdc_module_path *devpath; 183 184 BUG_ON(!entry); 185 186 devpath = &entry->devpath; 187 188 /* We expect the caller to set the ready flag to 0 if the hardware 189 path struct provided is invalid, so that we know we have to fill it. 190 First case, we don't have a preset hwpath... */ 191 if (!entry->ready) { 192 /* ...but we have a device, map it */ 193 BUG_ON(!entry->dev); 194 device_to_hwpath(entry->dev, (struct hardware_path *)devpath); 195 } 196 /* else, we expect the provided hwpath to be valid. */ 197 198 DPRINTK("%s: store: 0x%p, 0x%p, addr: 0x%lx\n", __func__, 199 entry, devpath, entry->addr); 200 201 /* addr, devpath and count must be word aligned */ 202 if (pdc_stable_write(entry->addr, devpath, sizeof(*devpath)) != PDC_OK) 203 WARN(1, KERN_ERR "%s: an error occurred when writing to PDC.\n" 204 "It is likely that the Stable Storage data has been corrupted.\n" 205 "Please check it carefully upon next reboot.\n", __func__); 206 207 /* kobject is already registered */ 208 entry->ready = 2; 209 210 DPRINTK("%s: device: 0x%p\n", __func__, entry->dev); 211} 212 213/** 214 * pdcspath_hwpath_read - This function handles hardware path pretty printing. 215 * @entry: An allocated and populated pdscpath_entry struct. 216 * @buf: The output buffer to write to. 217 * 218 * We will call this function to format the output of the hwpath attribute file. 219 */ 220static ssize_t 221pdcspath_hwpath_read(struct pdcspath_entry *entry, char *buf) 222{ 223 char *out = buf; 224 struct pdc_module_path *devpath; 225 short i; 226 227 if (!entry || !buf) 228 return -EINVAL; 229 230 read_lock(&entry->rw_lock); 231 devpath = &entry->devpath; 232 i = entry->ready; 233 read_unlock(&entry->rw_lock); 234 235 if (!i) /* entry is not ready */ 236 return -ENODATA; 237 238 for (i = 0; i < 6; i++) { 239 if (devpath->path.bc[i] < 0) 240 continue; 241 out += sprintf(out, "%d/", devpath->path.bc[i]); 242 } 243 out += sprintf(out, "%u\n", (unsigned char)devpath->path.mod); 244 245 return out - buf; 246} 247 248/** 249 * pdcspath_hwpath_write - This function handles hardware path modifying. 250 * @entry: An allocated and populated pdscpath_entry struct. 251 * @buf: The input buffer to read from. 252 * @count: The number of bytes to be read. 253 * 254 * We will call this function to change the current hardware path. 255 * Hardware paths are to be given '/'-delimited, without brackets. 256 * We make sure that the provided path actually maps to an existing 257 * device, BUT nothing would prevent some foolish user to set the path to some 258 * PCI bridge or even a CPU... 259 * A better work around would be to make sure we are at the end of a device tree 260 * for instance, but it would be IMHO beyond the simple scope of that driver. 261 * The aim is to provide a facility. Data correctness is left to userland. 262 */ 263static ssize_t 264pdcspath_hwpath_write(struct pdcspath_entry *entry, const char *buf, size_t count) 265{ 266 struct hardware_path hwpath; 267 unsigned short i; 268 char in[64], *temp; 269 struct device *dev; 270 int ret; 271 272 if (!entry || !buf || !count) 273 return -EINVAL; 274 275 /* We'll use a local copy of buf */ 276 count = min_t(size_t, count, sizeof(in)-1); 277 strscpy(in, buf, count + 1); 278 279 /* Let's clean up the target. 0xff is a blank pattern */ 280 memset(&hwpath, 0xff, sizeof(hwpath)); 281 282 /* First, pick the mod field (the last one of the input string) */ 283 if (!(temp = strrchr(in, '/'))) 284 return -EINVAL; 285 286 hwpath.mod = simple_strtoul(temp+1, NULL, 10); 287 in[temp-in] = '\0'; /* truncate the remaining string. just precaution */ 288 DPRINTK("%s: mod: %d\n", __func__, hwpath.mod); 289 290 /* Then, loop for each delimiter, making sure we don't have too many. 291 we write the bc fields in a down-top way. No matter what, we stop 292 before writing the last field. If there are too many fields anyway, 293 then the user is a moron and it'll be caught up later when we'll 294 check the consistency of the given hwpath. */ 295 for (i=5; ((temp = strrchr(in, '/'))) && (temp-in > 0) && (likely(i)); i--) { 296 hwpath.bc[i] = simple_strtoul(temp+1, NULL, 10); 297 in[temp-in] = '\0'; 298 DPRINTK("%s: bc[%d]: %d\n", __func__, i, hwpath.path.bc[i]); 299 } 300 301 /* Store the final field */ 302 hwpath.bc[i] = simple_strtoul(in, NULL, 10); 303 DPRINTK("%s: bc[%d]: %d\n", __func__, i, hwpath.path.bc[i]); 304 305 /* Now we check that the user isn't trying to lure us */ 306 if (!(dev = hwpath_to_device((struct hardware_path *)&hwpath))) { 307 printk(KERN_WARNING "%s: attempt to set invalid \"%s\" " 308 "hardware path: %s\n", __func__, entry->name, buf); 309 return -EINVAL; 310 } 311 312 /* So far so good, let's get in deep */ 313 write_lock(&entry->rw_lock); 314 entry->ready = 0; 315 entry->dev = dev; 316 317 /* Now, dive in. Write back to the hardware */ 318 pdcspath_store(entry); 319 320 /* Update the symlink to the real device */ 321 sysfs_remove_link(&entry->kobj, "device"); 322 write_unlock(&entry->rw_lock); 323 324 ret = sysfs_create_link(&entry->kobj, &entry->dev->kobj, "device"); 325 WARN_ON(ret); 326 327 printk(KERN_INFO PDCS_PREFIX ": changed \"%s\" path to \"%s\"\n", 328 entry->name, buf); 329 330 return count; 331} 332 333/** 334 * pdcspath_layer_read - Extended layer (eg. SCSI ids) pretty printing. 335 * @entry: An allocated and populated pdscpath_entry struct. 336 * @buf: The output buffer to write to. 337 * 338 * We will call this function to format the output of the layer attribute file. 339 */ 340static ssize_t 341pdcspath_layer_read(struct pdcspath_entry *entry, char *buf) 342{ 343 char *out = buf; 344 struct pdc_module_path *devpath; 345 short i; 346 347 if (!entry || !buf) 348 return -EINVAL; 349 350 read_lock(&entry->rw_lock); 351 devpath = &entry->devpath; 352 i = entry->ready; 353 read_unlock(&entry->rw_lock); 354 355 if (!i) /* entry is not ready */ 356 return -ENODATA; 357 358 for (i = 0; i < 6 && devpath->layers[i]; i++) 359 out += sprintf(out, "%u ", devpath->layers[i]); 360 361 out += sprintf(out, "\n"); 362 363 return out - buf; 364} 365 366/** 367 * pdcspath_layer_write - This function handles extended layer modifying. 368 * @entry: An allocated and populated pdscpath_entry struct. 369 * @buf: The input buffer to read from. 370 * @count: The number of bytes to be read. 371 * 372 * We will call this function to change the current layer value. 373 * Layers are to be given '.'-delimited, without brackets. 374 * XXX beware we are far less checky WRT input data provided than for hwpath. 375 * Potential harm can be done, since there's no way to check the validity of 376 * the layer fields. 377 */ 378static ssize_t 379pdcspath_layer_write(struct pdcspath_entry *entry, const char *buf, size_t count) 380{ 381 unsigned int layers[6]; /* device-specific info (ctlr#, unit#, ...) */ 382 unsigned short i; 383 char in[64], *temp; 384 385 if (!entry || !buf || !count) 386 return -EINVAL; 387 388 /* We'll use a local copy of buf */ 389 count = min_t(size_t, count, sizeof(in)-1); 390 strscpy(in, buf, count + 1); 391 392 /* Let's clean up the target. 0 is a blank pattern */ 393 memset(&layers, 0, sizeof(layers)); 394 395 /* First, pick the first layer */ 396 if (unlikely(!isdigit(*in))) 397 return -EINVAL; 398 layers[0] = simple_strtoul(in, NULL, 10); 399 DPRINTK("%s: layer[0]: %d\n", __func__, layers[0]); 400 401 temp = in; 402 for (i=1; ((temp = strchr(temp, '.'))) && (likely(i<6)); i++) { 403 if (unlikely(!isdigit(*(++temp)))) 404 return -EINVAL; 405 layers[i] = simple_strtoul(temp, NULL, 10); 406 DPRINTK("%s: layer[%d]: %d\n", __func__, i, layers[i]); 407 } 408 409 /* So far so good, let's get in deep */ 410 write_lock(&entry->rw_lock); 411 412 /* First, overwrite the current layers with the new ones, not touching 413 the hardware path. */ 414 memcpy(&entry->devpath.layers, &layers, sizeof(layers)); 415 416 /* Now, dive in. Write back to the hardware */ 417 pdcspath_store(entry); 418 write_unlock(&entry->rw_lock); 419 420 printk(KERN_INFO PDCS_PREFIX ": changed \"%s\" layers to \"%s\"\n", 421 entry->name, buf); 422 423 return count; 424} 425 426/** 427 * pdcspath_attr_show - Generic read function call wrapper. 428 * @kobj: The kobject to get info from. 429 * @attr: The attribute looked upon. 430 * @buf: The output buffer. 431 */ 432static ssize_t 433pdcspath_attr_show(struct kobject *kobj, struct attribute *attr, char *buf) 434{ 435 struct pdcspath_entry *entry = to_pdcspath_entry(kobj); 436 struct pdcspath_attribute *pdcs_attr = to_pdcspath_attribute(attr); 437 ssize_t ret = 0; 438 439 if (pdcs_attr->show) 440 ret = pdcs_attr->show(entry, buf); 441 442 return ret; 443} 444 445/** 446 * pdcspath_attr_store - Generic write function call wrapper. 447 * @kobj: The kobject to write info to. 448 * @attr: The attribute to be modified. 449 * @buf: The input buffer. 450 * @count: The size of the buffer. 451 */ 452static ssize_t 453pdcspath_attr_store(struct kobject *kobj, struct attribute *attr, 454 const char *buf, size_t count) 455{ 456 struct pdcspath_entry *entry = to_pdcspath_entry(kobj); 457 struct pdcspath_attribute *pdcs_attr = to_pdcspath_attribute(attr); 458 ssize_t ret = 0; 459 460 if (!capable(CAP_SYS_ADMIN)) 461 return -EACCES; 462 463 if (pdcs_attr->store) 464 ret = pdcs_attr->store(entry, buf, count); 465 466 return ret; 467} 468 469static const struct sysfs_ops pdcspath_attr_ops = { 470 .show = pdcspath_attr_show, 471 .store = pdcspath_attr_store, 472}; 473 474/* These are the two attributes of any PDC path. */ 475static PATHS_ATTR(hwpath, 0644, pdcspath_hwpath_read, pdcspath_hwpath_write); 476static PATHS_ATTR(layer, 0644, pdcspath_layer_read, pdcspath_layer_write); 477 478static struct attribute *paths_subsys_attrs[] = { 479 &paths_attr_hwpath.attr, 480 &paths_attr_layer.attr, 481 NULL, 482}; 483ATTRIBUTE_GROUPS(paths_subsys); 484 485/* Specific kobject type for our PDC paths */ 486static struct kobj_type ktype_pdcspath = { 487 .sysfs_ops = &pdcspath_attr_ops, 488 .default_groups = paths_subsys_groups, 489}; 490 491/* We hard define the 4 types of path we expect to find */ 492static PDCSPATH_ENTRY(PDCS_ADDR_PPRI, primary); 493static PDCSPATH_ENTRY(PDCS_ADDR_PCON, console); 494static PDCSPATH_ENTRY(PDCS_ADDR_PALT, alternative); 495static PDCSPATH_ENTRY(PDCS_ADDR_PKBD, keyboard); 496 497/* An array containing all PDC paths we will deal with */ 498static struct pdcspath_entry *pdcspath_entries[] = { 499 &pdcspath_entry_primary, 500 &pdcspath_entry_alternative, 501 &pdcspath_entry_console, 502 &pdcspath_entry_keyboard, 503 NULL, 504}; 505 506 507/* For more insight of what's going on here, refer to PDC Procedures doc, 508 * Section PDC_STABLE */ 509 510/** 511 * pdcs_size_read - Stable Storage size output. 512 * @kobj: The kobject used to share data with userspace. 513 * @attr: The kobject attributes. 514 * @buf: The output buffer to write to. 515 */ 516static ssize_t pdcs_size_read(struct kobject *kobj, 517 struct kobj_attribute *attr, 518 char *buf) 519{ 520 char *out = buf; 521 522 if (!buf) 523 return -EINVAL; 524 525 /* show the size of the stable storage */ 526 out += sprintf(out, "%ld\n", pdcs_size); 527 528 return out - buf; 529} 530 531/** 532 * pdcs_auto_read - Stable Storage autoboot/search flag output. 533 * @kobj: The kobject used to share data with userspace. 534 * @attr: The kobject attributes. 535 * @buf: The output buffer to write to. 536 * @knob: The PF_AUTOBOOT or PF_AUTOSEARCH flag 537 */ 538static ssize_t pdcs_auto_read(struct kobject *kobj, 539 struct kobj_attribute *attr, 540 char *buf, int knob) 541{ 542 char *out = buf; 543 struct pdcspath_entry *pathentry; 544 545 if (!buf) 546 return -EINVAL; 547 548 /* Current flags are stored in primary boot path entry */ 549 pathentry = &pdcspath_entry_primary; 550 551 read_lock(&pathentry->rw_lock); 552 out += sprintf(out, "%s\n", (pathentry->devpath.path.flags & knob) ? 553 "On" : "Off"); 554 read_unlock(&pathentry->rw_lock); 555 556 return out - buf; 557} 558 559/** 560 * pdcs_autoboot_read - Stable Storage autoboot flag output. 561 * @kobj: The kobject used to share data with userspace. 562 * @attr: The kobject attributes. 563 * @buf: The output buffer to write to. 564 */ 565static ssize_t pdcs_autoboot_read(struct kobject *kobj, 566 struct kobj_attribute *attr, char *buf) 567{ 568 return pdcs_auto_read(kobj, attr, buf, PF_AUTOBOOT); 569} 570 571/** 572 * pdcs_autosearch_read - Stable Storage autoboot flag output. 573 * @kobj: The kobject used to share data with userspace. 574 * @attr: The kobject attributes. 575 * @buf: The output buffer to write to. 576 */ 577static ssize_t pdcs_autosearch_read(struct kobject *kobj, 578 struct kobj_attribute *attr, char *buf) 579{ 580 return pdcs_auto_read(kobj, attr, buf, PF_AUTOSEARCH); 581} 582 583/** 584 * pdcs_timer_read - Stable Storage timer count output (in seconds). 585 * @kobj: The kobject used to share data with userspace. 586 * @attr: The kobject attributes. 587 * @buf: The output buffer to write to. 588 * 589 * The value of the timer field correponds to a number of seconds in powers of 2. 590 */ 591static ssize_t pdcs_timer_read(struct kobject *kobj, 592 struct kobj_attribute *attr, char *buf) 593{ 594 char *out = buf; 595 struct pdcspath_entry *pathentry; 596 597 if (!buf) 598 return -EINVAL; 599 600 /* Current flags are stored in primary boot path entry */ 601 pathentry = &pdcspath_entry_primary; 602 603 /* print the timer value in seconds */ 604 read_lock(&pathentry->rw_lock); 605 out += sprintf(out, "%u\n", (pathentry->devpath.path.flags & PF_TIMER) ? 606 (1 << (pathentry->devpath.path.flags & PF_TIMER)) : 0); 607 read_unlock(&pathentry->rw_lock); 608 609 return out - buf; 610} 611 612/** 613 * pdcs_osid_read - Stable Storage OS ID register output. 614 * @kobj: The kobject used to share data with userspace. 615 * @attr: The kobject attributes. 616 * @buf: The output buffer to write to. 617 */ 618static ssize_t pdcs_osid_read(struct kobject *kobj, 619 struct kobj_attribute *attr, char *buf) 620{ 621 char *out = buf; 622 623 if (!buf) 624 return -EINVAL; 625 626 out += sprintf(out, "%s dependent data (0x%.4x)\n", 627 os_id_to_string(pdcs_osid), pdcs_osid); 628 629 return out - buf; 630} 631 632/** 633 * pdcs_osdep1_read - Stable Storage OS-Dependent data area 1 output. 634 * @kobj: The kobject used to share data with userspace. 635 * @attr: The kobject attributes. 636 * @buf: The output buffer to write to. 637 * 638 * This can hold 16 bytes of OS-Dependent data. 639 */ 640static ssize_t pdcs_osdep1_read(struct kobject *kobj, 641 struct kobj_attribute *attr, char *buf) 642{ 643 char *out = buf; 644 u32 result[4]; 645 646 if (!buf) 647 return -EINVAL; 648 649 if (pdc_stable_read(PDCS_ADDR_OSD1, &result, sizeof(result)) != PDC_OK) 650 return -EIO; 651 652 out += sprintf(out, "0x%.8x\n", result[0]); 653 out += sprintf(out, "0x%.8x\n", result[1]); 654 out += sprintf(out, "0x%.8x\n", result[2]); 655 out += sprintf(out, "0x%.8x\n", result[3]); 656 657 return out - buf; 658} 659 660/** 661 * pdcs_diagnostic_read - Stable Storage Diagnostic register output. 662 * @kobj: The kobject used to share data with userspace. 663 * @attr: The kobject attributes. 664 * @buf: The output buffer to write to. 665 * 666 * I have NFC how to interpret the content of that register ;-). 667 */ 668static ssize_t pdcs_diagnostic_read(struct kobject *kobj, 669 struct kobj_attribute *attr, char *buf) 670{ 671 char *out = buf; 672 u32 result; 673 674 if (!buf) 675 return -EINVAL; 676 677 /* get diagnostic */ 678 if (pdc_stable_read(PDCS_ADDR_DIAG, &result, sizeof(result)) != PDC_OK) 679 return -EIO; 680 681 out += sprintf(out, "0x%.4x\n", (result >> 16)); 682 683 return out - buf; 684} 685 686/** 687 * pdcs_fastsize_read - Stable Storage FastSize register output. 688 * @kobj: The kobject used to share data with userspace. 689 * @attr: The kobject attributes. 690 * @buf: The output buffer to write to. 691 * 692 * This register holds the amount of system RAM to be tested during boot sequence. 693 */ 694static ssize_t pdcs_fastsize_read(struct kobject *kobj, 695 struct kobj_attribute *attr, char *buf) 696{ 697 char *out = buf; 698 u32 result; 699 700 if (!buf) 701 return -EINVAL; 702 703 /* get fast-size */ 704 if (pdc_stable_read(PDCS_ADDR_FSIZ, &result, sizeof(result)) != PDC_OK) 705 return -EIO; 706 707 if ((result & 0x0F) < 0x0E) 708 out += sprintf(out, "%d kB", (1<<(result & 0x0F))*256); 709 else 710 out += sprintf(out, "All"); 711 out += sprintf(out, "\n"); 712 713 return out - buf; 714} 715 716/** 717 * pdcs_osdep2_read - Stable Storage OS-Dependent data area 2 output. 718 * @kobj: The kobject used to share data with userspace. 719 * @attr: The kobject attributes. 720 * @buf: The output buffer to write to. 721 * 722 * This can hold pdcs_size - 224 bytes of OS-Dependent data, when available. 723 */ 724static ssize_t pdcs_osdep2_read(struct kobject *kobj, 725 struct kobj_attribute *attr, char *buf) 726{ 727 char *out = buf; 728 unsigned long size; 729 unsigned short i; 730 u32 result; 731 732 if (unlikely(pdcs_size <= 224)) 733 return -ENODATA; 734 735 size = pdcs_size - 224; 736 737 if (!buf) 738 return -EINVAL; 739 740 for (i=0; i<size; i+=4) { 741 if (unlikely(pdc_stable_read(PDCS_ADDR_OSD2 + i, &result, 742 sizeof(result)) != PDC_OK)) 743 return -EIO; 744 out += sprintf(out, "0x%.8x\n", result); 745 } 746 747 return out - buf; 748} 749 750/** 751 * pdcs_auto_write - This function handles autoboot/search flag modifying. 752 * @kobj: The kobject used to share data with userspace. 753 * @attr: The kobject attributes. 754 * @buf: The input buffer to read from. 755 * @count: The number of bytes to be read. 756 * @knob: The PF_AUTOBOOT or PF_AUTOSEARCH flag 757 * 758 * We will call this function to change the current autoboot flag. 759 * We expect a precise syntax: 760 * \"n\" (n == 0 or 1) to toggle AutoBoot Off or On 761 */ 762static ssize_t pdcs_auto_write(struct kobject *kobj, 763 struct kobj_attribute *attr, const char *buf, 764 size_t count, int knob) 765{ 766 struct pdcspath_entry *pathentry; 767 unsigned char flags; 768 char in[8], *temp; 769 char c; 770 771 if (!capable(CAP_SYS_ADMIN)) 772 return -EACCES; 773 774 if (!buf || !count) 775 return -EINVAL; 776 777 /* We'll use a local copy of buf */ 778 count = min_t(size_t, count, sizeof(in)-1); 779 strscpy(in, buf, count + 1); 780 781 /* Current flags are stored in primary boot path entry */ 782 pathentry = &pdcspath_entry_primary; 783 784 /* Be nice to the existing flag record */ 785 read_lock(&pathentry->rw_lock); 786 flags = pathentry->devpath.path.flags; 787 read_unlock(&pathentry->rw_lock); 788 789 DPRINTK("%s: flags before: 0x%X\n", __func__, flags); 790 791 temp = skip_spaces(in); 792 793 c = *temp++ - '0'; 794 if ((c != 0) && (c != 1)) 795 goto parse_error; 796 if (c == 0) 797 flags &= ~knob; 798 else 799 flags |= knob; 800 801 DPRINTK("%s: flags after: 0x%X\n", __func__, flags); 802 803 /* So far so good, let's get in deep */ 804 write_lock(&pathentry->rw_lock); 805 806 /* Change the path entry flags first */ 807 pathentry->devpath.path.flags = flags; 808 809 /* Now, dive in. Write back to the hardware */ 810 pdcspath_store(pathentry); 811 write_unlock(&pathentry->rw_lock); 812 813 printk(KERN_INFO PDCS_PREFIX ": changed \"%s\" to \"%s\"\n", 814 (knob & PF_AUTOBOOT) ? "autoboot" : "autosearch", 815 (flags & knob) ? "On" : "Off"); 816 817 return count; 818 819parse_error: 820 printk(KERN_WARNING "%s: Parse error: expect \"n\" (n == 0 or 1)\n", __func__); 821 return -EINVAL; 822} 823 824/** 825 * pdcs_autoboot_write - This function handles autoboot flag modifying. 826 * @kobj: The kobject used to share data with userspace. 827 * @attr: The kobject attributes. 828 * @buf: The input buffer to read from. 829 * @count: The number of bytes to be read. 830 * 831 * We will call this function to change the current boot flags. 832 * We expect a precise syntax: 833 * \"n\" (n == 0 or 1) to toggle AutoSearch Off or On 834 */ 835static ssize_t pdcs_autoboot_write(struct kobject *kobj, 836 struct kobj_attribute *attr, 837 const char *buf, size_t count) 838{ 839 return pdcs_auto_write(kobj, attr, buf, count, PF_AUTOBOOT); 840} 841 842/** 843 * pdcs_autosearch_write - This function handles autosearch flag modifying. 844 * @kobj: The kobject used to share data with userspace. 845 * @attr: The kobject attributes. 846 * @buf: The input buffer to read from. 847 * @count: The number of bytes to be read. 848 * 849 * We will call this function to change the current boot flags. 850 * We expect a precise syntax: 851 * \"n\" (n == 0 or 1) to toggle AutoSearch Off or On 852 */ 853static ssize_t pdcs_autosearch_write(struct kobject *kobj, 854 struct kobj_attribute *attr, 855 const char *buf, size_t count) 856{ 857 return pdcs_auto_write(kobj, attr, buf, count, PF_AUTOSEARCH); 858} 859 860/** 861 * pdcs_osdep1_write - Stable Storage OS-Dependent data area 1 input. 862 * @kobj: The kobject used to share data with userspace. 863 * @attr: The kobject attributes. 864 * @buf: The input buffer to read from. 865 * @count: The number of bytes to be read. 866 * 867 * This can store 16 bytes of OS-Dependent data. We use a byte-by-byte 868 * write approach. It's up to userspace to deal with it when constructing 869 * its input buffer. 870 */ 871static ssize_t pdcs_osdep1_write(struct kobject *kobj, 872 struct kobj_attribute *attr, 873 const char *buf, size_t count) 874{ 875 u8 in[16]; 876 877 if (!capable(CAP_SYS_ADMIN)) 878 return -EACCES; 879 880 if (!buf || !count) 881 return -EINVAL; 882 883 if (unlikely(pdcs_osid != OS_ID_LINUX)) 884 return -EPERM; 885 886 if (count > 16) 887 return -EMSGSIZE; 888 889 /* We'll use a local copy of buf */ 890 memset(in, 0, 16); 891 memcpy(in, buf, count); 892 893 if (pdc_stable_write(PDCS_ADDR_OSD1, &in, sizeof(in)) != PDC_OK) 894 return -EIO; 895 896 return count; 897} 898 899/** 900 * pdcs_osdep2_write - Stable Storage OS-Dependent data area 2 input. 901 * @kobj: The kobject used to share data with userspace. 902 * @attr: The kobject attributes. 903 * @buf: The input buffer to read from. 904 * @count: The number of bytes to be read. 905 * 906 * This can store pdcs_size - 224 bytes of OS-Dependent data. We use a 907 * byte-by-byte write approach. It's up to userspace to deal with it when 908 * constructing its input buffer. 909 */ 910static ssize_t pdcs_osdep2_write(struct kobject *kobj, 911 struct kobj_attribute *attr, 912 const char *buf, size_t count) 913{ 914 unsigned long size; 915 unsigned short i; 916 u8 in[4]; 917 918 if (!capable(CAP_SYS_ADMIN)) 919 return -EACCES; 920 921 if (!buf || !count) 922 return -EINVAL; 923 924 if (unlikely(pdcs_size <= 224)) 925 return -ENOSYS; 926 927 if (unlikely(pdcs_osid != OS_ID_LINUX)) 928 return -EPERM; 929 930 size = pdcs_size - 224; 931 932 if (count > size) 933 return -EMSGSIZE; 934 935 /* We'll use a local copy of buf */ 936 937 for (i=0; i<count; i+=4) { 938 memset(in, 0, 4); 939 memcpy(in, buf+i, (count-i < 4) ? count-i : 4); 940 if (unlikely(pdc_stable_write(PDCS_ADDR_OSD2 + i, &in, 941 sizeof(in)) != PDC_OK)) 942 return -EIO; 943 } 944 945 return count; 946} 947 948/* The remaining attributes. */ 949static PDCS_ATTR(size, 0444, pdcs_size_read, NULL); 950static PDCS_ATTR(autoboot, 0644, pdcs_autoboot_read, pdcs_autoboot_write); 951static PDCS_ATTR(autosearch, 0644, pdcs_autosearch_read, pdcs_autosearch_write); 952static PDCS_ATTR(timer, 0444, pdcs_timer_read, NULL); 953static PDCS_ATTR(osid, 0444, pdcs_osid_read, NULL); 954static PDCS_ATTR(osdep1, 0600, pdcs_osdep1_read, pdcs_osdep1_write); 955static PDCS_ATTR(diagnostic, 0400, pdcs_diagnostic_read, NULL); 956static PDCS_ATTR(fastsize, 0400, pdcs_fastsize_read, NULL); 957static PDCS_ATTR(osdep2, 0600, pdcs_osdep2_read, pdcs_osdep2_write); 958 959static struct attribute *pdcs_subsys_attrs[] = { 960 &pdcs_attr_size.attr, 961 &pdcs_attr_autoboot.attr, 962 &pdcs_attr_autosearch.attr, 963 &pdcs_attr_timer.attr, 964 &pdcs_attr_osid.attr, 965 &pdcs_attr_osdep1.attr, 966 &pdcs_attr_diagnostic.attr, 967 &pdcs_attr_fastsize.attr, 968 &pdcs_attr_osdep2.attr, 969 NULL, 970}; 971 972static const struct attribute_group pdcs_attr_group = { 973 .attrs = pdcs_subsys_attrs, 974}; 975 976static struct kobject *stable_kobj; 977static struct kset *paths_kset; 978 979/** 980 * pdcs_register_pathentries - Prepares path entries kobjects for sysfs usage. 981 * 982 * It creates kobjects corresponding to each path entry with nice sysfs 983 * links to the real device. This is where the magic takes place: when 984 * registering the subsystem attributes during module init, each kobject hereby 985 * created will show in the sysfs tree as a folder containing files as defined 986 * by path_subsys_attr[]. 987 */ 988static inline int __init 989pdcs_register_pathentries(void) 990{ 991 unsigned short i; 992 struct pdcspath_entry *entry; 993 int err; 994 995 /* Initialize the entries rw_lock before anything else */ 996 for (i = 0; (entry = pdcspath_entries[i]); i++) 997 rwlock_init(&entry->rw_lock); 998 999 for (i = 0; (entry = pdcspath_entries[i]); i++) { 1000 write_lock(&entry->rw_lock); 1001 err = pdcspath_fetch(entry); 1002 write_unlock(&entry->rw_lock); 1003 1004 if (err < 0) 1005 continue; 1006 1007 entry->kobj.kset = paths_kset; 1008 err = kobject_init_and_add(&entry->kobj, &ktype_pdcspath, NULL, 1009 "%s", entry->name); 1010 if (err) { 1011 kobject_put(&entry->kobj); 1012 return err; 1013 } 1014 1015 /* kobject is now registered */ 1016 write_lock(&entry->rw_lock); 1017 entry->ready = 2; 1018 write_unlock(&entry->rw_lock); 1019 1020 /* Add a nice symlink to the real device */ 1021 if (entry->dev) { 1022 err = sysfs_create_link(&entry->kobj, &entry->dev->kobj, "device"); 1023 WARN_ON(err); 1024 } 1025 1026 kobject_uevent(&entry->kobj, KOBJ_ADD); 1027 } 1028 1029 return 0; 1030} 1031 1032/** 1033 * pdcs_unregister_pathentries - Routine called when unregistering the module. 1034 */ 1035static inline void 1036pdcs_unregister_pathentries(void) 1037{ 1038 unsigned short i; 1039 struct pdcspath_entry *entry; 1040 1041 for (i = 0; (entry = pdcspath_entries[i]); i++) { 1042 read_lock(&entry->rw_lock); 1043 if (entry->ready >= 2) 1044 kobject_put(&entry->kobj); 1045 read_unlock(&entry->rw_lock); 1046 } 1047} 1048 1049/* 1050 * For now we register the stable subsystem with the firmware subsystem 1051 * and the paths subsystem with the stable subsystem 1052 */ 1053static int __init 1054pdc_stable_init(void) 1055{ 1056 int rc = 0, error; 1057 u32 result; 1058 1059 /* find the size of the stable storage */ 1060 if (pdc_stable_get_size(&pdcs_size) != PDC_OK) 1061 return -ENODEV; 1062 1063 /* make sure we have enough data */ 1064 if (pdcs_size < 96) 1065 return -ENODATA; 1066 1067 printk(KERN_INFO PDCS_PREFIX " facility v%s\n", PDCS_VERSION); 1068 1069 /* get OSID */ 1070 if (pdc_stable_read(PDCS_ADDR_OSID, &result, sizeof(result)) != PDC_OK) 1071 return -EIO; 1072 1073 /* the actual result is 16 bits away */ 1074 pdcs_osid = (u16)(result >> 16); 1075 1076 /* For now we'll register the directory at /sys/firmware/stable */ 1077 stable_kobj = kobject_create_and_add("stable", firmware_kobj); 1078 if (!stable_kobj) { 1079 rc = -ENOMEM; 1080 goto fail_firmreg; 1081 } 1082 1083 /* Don't forget the root entries */ 1084 error = sysfs_create_group(stable_kobj, &pdcs_attr_group); 1085 if (error) { 1086 rc = -ENOMEM; 1087 goto fail_ksetreg; 1088 } 1089 1090 /* register the paths kset as a child of the stable kset */ 1091 paths_kset = kset_create_and_add("paths", NULL, stable_kobj); 1092 if (!paths_kset) { 1093 rc = -ENOMEM; 1094 goto fail_ksetreg; 1095 } 1096 1097 /* now we create all "files" for the paths kset */ 1098 if ((rc = pdcs_register_pathentries())) 1099 goto fail_pdcsreg; 1100 1101 return rc; 1102 1103fail_pdcsreg: 1104 pdcs_unregister_pathentries(); 1105 kset_unregister(paths_kset); 1106 1107fail_ksetreg: 1108 kobject_put(stable_kobj); 1109 1110fail_firmreg: 1111 printk(KERN_INFO PDCS_PREFIX " bailing out\n"); 1112 return rc; 1113} 1114 1115static void __exit 1116pdc_stable_exit(void) 1117{ 1118 pdcs_unregister_pathentries(); 1119 kset_unregister(paths_kset); 1120 kobject_put(stable_kobj); 1121} 1122 1123 1124module_init(pdc_stable_init); 1125module_exit(pdc_stable_exit); 1126