linux/drivers/parisc/pdc_stable.c
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   1/* 
   2 *    Interfaces to retrieve and set PDC Stable options (firmware)
   3 *
   4 *    Copyright (C) 2005-2006 Thibaut VARENE <varenet@parisc-linux.org>
   5 *
   6 *    This program is free software; you can redistribute it and/or modify
   7 *    it under the terms of the GNU General Public License, version 2, as
   8 *    published by the Free Software Foundation.
   9 *
  10 *    This program is distributed in the hope that it will be useful,
  11 *    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12 *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13 *    GNU General Public License for more details.
  14 *
  15 *    You should have received a copy of the GNU General Public License
  16 *    along with this program; if not, write to the Free Software
  17 *    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  18 *
  19 *
  20 *    DEV NOTE: the PDC Procedures reference states that:
  21 *    "A minimum of 96 bytes of Stable Storage is required. Providing more than
  22 *    96 bytes of Stable Storage is optional [...]. Failure to provide the
  23 *    optional locations from 96 to 192 results in the loss of certain
  24 *    functionality during boot."
  25 *
  26 *    Since locations between 96 and 192 are the various paths, most (if not
  27 *    all) PA-RISC machines should have them. Anyway, for safety reasons, the
  28 *    following code can deal with just 96 bytes of Stable Storage, and all
  29 *    sizes between 96 and 192 bytes (provided they are multiple of struct
  30 *    device_path size, eg: 128, 160 and 192) to provide full information.
  31 *    One last word: there's one path we can always count on: the primary path.
  32 *    Anything above 224 bytes is used for 'osdep2' OS-dependent storage area.
  33 *
  34 *    The first OS-dependent area should always be available. Obviously, this is
  35 *    not true for the other one. Also bear in mind that reading/writing from/to
  36 *    osdep2 is much more expensive than from/to osdep1.
  37 *    NOTE: We do not handle the 2 bytes OS-dep area at 0x5D, nor the first
  38 *    2 bytes of storage available right after OSID. That's a total of 4 bytes
  39 *    sacrificed: -ETOOLAZY :P
  40 *
  41 *    The current policy wrt file permissions is:
  42 *      - write: root only
  43 *      - read: (reading triggers PDC calls) ? root only : everyone
  44 *    The rationale is that PDC calls could hog (DoS) the machine.
  45 *
  46 *      TODO:
  47 *      - timer/fastsize write calls
  48 */
  49
  50#undef PDCS_DEBUG
  51#ifdef PDCS_DEBUG
  52#define DPRINTK(fmt, args...)   printk(KERN_DEBUG fmt, ## args)
  53#else
  54#define DPRINTK(fmt, args...)
  55#endif
  56
  57#include <linux/module.h>
  58#include <linux/init.h>
  59#include <linux/kernel.h>
  60#include <linux/string.h>
  61#include <linux/capability.h>
  62#include <linux/ctype.h>
  63#include <linux/sysfs.h>
  64#include <linux/kobject.h>
  65#include <linux/device.h>
  66#include <linux/errno.h>
  67#include <linux/spinlock.h>
  68
  69#include <asm/pdc.h>
  70#include <asm/page.h>
  71#include <asm/uaccess.h>
  72#include <asm/hardware.h>
  73
  74#define PDCS_VERSION    "0.30"
  75#define PDCS_PREFIX     "PDC Stable Storage"
  76
  77#define PDCS_ADDR_PPRI  0x00
  78#define PDCS_ADDR_OSID  0x40
  79#define PDCS_ADDR_OSD1  0x48
  80#define PDCS_ADDR_DIAG  0x58
  81#define PDCS_ADDR_FSIZ  0x5C
  82#define PDCS_ADDR_PCON  0x60
  83#define PDCS_ADDR_PALT  0x80
  84#define PDCS_ADDR_PKBD  0xA0
  85#define PDCS_ADDR_OSD2  0xE0
  86
  87MODULE_AUTHOR("Thibaut VARENE <varenet@parisc-linux.org>");
  88MODULE_DESCRIPTION("sysfs interface to HP PDC Stable Storage data");
  89MODULE_LICENSE("GPL");
  90MODULE_VERSION(PDCS_VERSION);
  91
  92/* holds Stable Storage size. Initialized once and for all, no lock needed */
  93static unsigned long pdcs_size __read_mostly;
  94
  95/* holds OS ID. Initialized once and for all, hopefully to 0x0006 */
  96static u16 pdcs_osid __read_mostly;
  97
  98/* This struct defines what we need to deal with a parisc pdc path entry */
  99struct pdcspath_entry {
 100        rwlock_t rw_lock;               /* to protect path entry access */
 101        short ready;                    /* entry record is valid if != 0 */
 102        unsigned long addr;             /* entry address in stable storage */
 103        char *name;                     /* entry name */
 104        struct device_path devpath;     /* device path in parisc representation */
 105        struct device *dev;             /* corresponding device */
 106        struct kobject kobj;
 107};
 108
 109struct pdcspath_attribute {
 110        struct attribute attr;
 111        ssize_t (*show)(struct pdcspath_entry *entry, char *buf);
 112        ssize_t (*store)(struct pdcspath_entry *entry, const char *buf, size_t count);
 113};
 114
 115#define PDCSPATH_ENTRY(_addr, _name) \
 116struct pdcspath_entry pdcspath_entry_##_name = { \
 117        .ready = 0, \
 118        .addr = _addr, \
 119        .name = __stringify(_name), \
 120};
 121
 122#define PDCS_ATTR(_name, _mode, _show, _store) \
 123struct kobj_attribute pdcs_attr_##_name = { \
 124        .attr = {.name = __stringify(_name), .mode = _mode}, \
 125        .show = _show, \
 126        .store = _store, \
 127};
 128
 129#define PATHS_ATTR(_name, _mode, _show, _store) \
 130struct pdcspath_attribute paths_attr_##_name = { \
 131        .attr = {.name = __stringify(_name), .mode = _mode}, \
 132        .show = _show, \
 133        .store = _store, \
 134};
 135
 136#define to_pdcspath_attribute(_attr) container_of(_attr, struct pdcspath_attribute, attr)
 137#define to_pdcspath_entry(obj)  container_of(obj, struct pdcspath_entry, kobj)
 138
 139/**
 140 * pdcspath_fetch - This function populates the path entry structs.
 141 * @entry: A pointer to an allocated pdcspath_entry.
 142 * 
 143 * The general idea is that you don't read from the Stable Storage every time
 144 * you access the files provided by the facilities. We store a copy of the
 145 * content of the stable storage WRT various paths in these structs. We read
 146 * these structs when reading the files, and we will write to these structs when
 147 * writing to the files, and only then write them back to the Stable Storage.
 148 *
 149 * This function expects to be called with @entry->rw_lock write-hold.
 150 */
 151static int
 152pdcspath_fetch(struct pdcspath_entry *entry)
 153{
 154        struct device_path *devpath;
 155
 156        if (!entry)
 157                return -EINVAL;
 158
 159        devpath = &entry->devpath;
 160        
 161        DPRINTK("%s: fetch: 0x%p, 0x%p, addr: 0x%lx\n", __func__,
 162                        entry, devpath, entry->addr);
 163
 164        /* addr, devpath and count must be word aligned */
 165        if (pdc_stable_read(entry->addr, devpath, sizeof(*devpath)) != PDC_OK)
 166                return -EIO;
 167                
 168        /* Find the matching device.
 169           NOTE: hardware_path overlays with device_path, so the nice cast can
 170           be used */
 171        entry->dev = hwpath_to_device((struct hardware_path *)devpath);
 172
 173        entry->ready = 1;
 174        
 175        DPRINTK("%s: device: 0x%p\n", __func__, entry->dev);
 176        
 177        return 0;
 178}
 179
 180/**
 181 * pdcspath_store - This function writes a path to stable storage.
 182 * @entry: A pointer to an allocated pdcspath_entry.
 183 * 
 184 * It can be used in two ways: either by passing it a preset devpath struct
 185 * containing an already computed hardware path, or by passing it a device
 186 * pointer, from which it'll find out the corresponding hardware path.
 187 * For now we do not handle the case where there's an error in writing to the
 188 * Stable Storage area, so you'd better not mess up the data :P
 189 *
 190 * This function expects to be called with @entry->rw_lock write-hold.
 191 */
 192static void
 193pdcspath_store(struct pdcspath_entry *entry)
 194{
 195        struct device_path *devpath;
 196
 197        BUG_ON(!entry);
 198
 199        devpath = &entry->devpath;
 200        
 201        /* We expect the caller to set the ready flag to 0 if the hardware
 202           path struct provided is invalid, so that we know we have to fill it.
 203           First case, we don't have a preset hwpath... */
 204        if (!entry->ready) {
 205                /* ...but we have a device, map it */
 206                BUG_ON(!entry->dev);
 207                device_to_hwpath(entry->dev, (struct hardware_path *)devpath);
 208        }
 209        /* else, we expect the provided hwpath to be valid. */
 210        
 211        DPRINTK("%s: store: 0x%p, 0x%p, addr: 0x%lx\n", __func__,
 212                        entry, devpath, entry->addr);
 213
 214        /* addr, devpath and count must be word aligned */
 215        if (pdc_stable_write(entry->addr, devpath, sizeof(*devpath)) != PDC_OK) {
 216                printk(KERN_ERR "%s: an error occurred when writing to PDC.\n"
 217                                "It is likely that the Stable Storage data has been corrupted.\n"
 218                                "Please check it carefully upon next reboot.\n", __func__);
 219                WARN_ON(1);
 220        }
 221                
 222        /* kobject is already registered */
 223        entry->ready = 2;
 224        
 225        DPRINTK("%s: device: 0x%p\n", __func__, entry->dev);
 226}
 227
 228/**
 229 * pdcspath_hwpath_read - This function handles hardware path pretty printing.
 230 * @entry: An allocated and populated pdscpath_entry struct.
 231 * @buf: The output buffer to write to.
 232 * 
 233 * We will call this function to format the output of the hwpath attribute file.
 234 */
 235static ssize_t
 236pdcspath_hwpath_read(struct pdcspath_entry *entry, char *buf)
 237{
 238        char *out = buf;
 239        struct device_path *devpath;
 240        short i;
 241
 242        if (!entry || !buf)
 243                return -EINVAL;
 244
 245        read_lock(&entry->rw_lock);
 246        devpath = &entry->devpath;
 247        i = entry->ready;
 248        read_unlock(&entry->rw_lock);
 249
 250        if (!i) /* entry is not ready */
 251                return -ENODATA;
 252        
 253        for (i = 0; i < 6; i++) {
 254                if (devpath->bc[i] >= 128)
 255                        continue;
 256                out += sprintf(out, "%u/", (unsigned char)devpath->bc[i]);
 257        }
 258        out += sprintf(out, "%u\n", (unsigned char)devpath->mod);
 259        
 260        return out - buf;
 261}
 262
 263/**
 264 * pdcspath_hwpath_write - This function handles hardware path modifying.
 265 * @entry: An allocated and populated pdscpath_entry struct.
 266 * @buf: The input buffer to read from.
 267 * @count: The number of bytes to be read.
 268 * 
 269 * We will call this function to change the current hardware path.
 270 * Hardware paths are to be given '/'-delimited, without brackets.
 271 * We make sure that the provided path actually maps to an existing
 272 * device, BUT nothing would prevent some foolish user to set the path to some
 273 * PCI bridge or even a CPU...
 274 * A better work around would be to make sure we are at the end of a device tree
 275 * for instance, but it would be IMHO beyond the simple scope of that driver.
 276 * The aim is to provide a facility. Data correctness is left to userland.
 277 */
 278static ssize_t
 279pdcspath_hwpath_write(struct pdcspath_entry *entry, const char *buf, size_t count)
 280{
 281        struct hardware_path hwpath;
 282        unsigned short i;
 283        char in[count+1], *temp;
 284        struct device *dev;
 285        int ret;
 286
 287        if (!entry || !buf || !count)
 288                return -EINVAL;
 289
 290        /* We'll use a local copy of buf */
 291        memset(in, 0, count+1);
 292        strncpy(in, buf, count);
 293        
 294        /* Let's clean up the target. 0xff is a blank pattern */
 295        memset(&hwpath, 0xff, sizeof(hwpath));
 296        
 297        /* First, pick the mod field (the last one of the input string) */
 298        if (!(temp = strrchr(in, '/')))
 299                return -EINVAL;
 300                        
 301        hwpath.mod = simple_strtoul(temp+1, NULL, 10);
 302        in[temp-in] = '\0';     /* truncate the remaining string. just precaution */
 303        DPRINTK("%s: mod: %d\n", __func__, hwpath.mod);
 304        
 305        /* Then, loop for each delimiter, making sure we don't have too many.
 306           we write the bc fields in a down-top way. No matter what, we stop
 307           before writing the last field. If there are too many fields anyway,
 308           then the user is a moron and it'll be caught up later when we'll
 309           check the consistency of the given hwpath. */
 310        for (i=5; ((temp = strrchr(in, '/'))) && (temp-in > 0) && (likely(i)); i--) {
 311                hwpath.bc[i] = simple_strtoul(temp+1, NULL, 10);
 312                in[temp-in] = '\0';
 313                DPRINTK("%s: bc[%d]: %d\n", __func__, i, hwpath.bc[i]);
 314        }
 315        
 316        /* Store the final field */             
 317        hwpath.bc[i] = simple_strtoul(in, NULL, 10);
 318        DPRINTK("%s: bc[%d]: %d\n", __func__, i, hwpath.bc[i]);
 319        
 320        /* Now we check that the user isn't trying to lure us */
 321        if (!(dev = hwpath_to_device((struct hardware_path *)&hwpath))) {
 322                printk(KERN_WARNING "%s: attempt to set invalid \"%s\" "
 323                        "hardware path: %s\n", __func__, entry->name, buf);
 324                return -EINVAL;
 325        }
 326        
 327        /* So far so good, let's get in deep */
 328        write_lock(&entry->rw_lock);
 329        entry->ready = 0;
 330        entry->dev = dev;
 331        
 332        /* Now, dive in. Write back to the hardware */
 333        pdcspath_store(entry);
 334        
 335        /* Update the symlink to the real device */
 336        sysfs_remove_link(&entry->kobj, "device");
 337        ret = sysfs_create_link(&entry->kobj, &entry->dev->kobj, "device");
 338        WARN_ON(ret);
 339
 340        write_unlock(&entry->rw_lock);
 341        
 342        printk(KERN_INFO PDCS_PREFIX ": changed \"%s\" path to \"%s\"\n",
 343                entry->name, buf);
 344        
 345        return count;
 346}
 347
 348/**
 349 * pdcspath_layer_read - Extended layer (eg. SCSI ids) pretty printing.
 350 * @entry: An allocated and populated pdscpath_entry struct.
 351 * @buf: The output buffer to write to.
 352 * 
 353 * We will call this function to format the output of the layer attribute file.
 354 */
 355static ssize_t
 356pdcspath_layer_read(struct pdcspath_entry *entry, char *buf)
 357{
 358        char *out = buf;
 359        struct device_path *devpath;
 360        short i;
 361
 362        if (!entry || !buf)
 363                return -EINVAL;
 364        
 365        read_lock(&entry->rw_lock);
 366        devpath = &entry->devpath;
 367        i = entry->ready;
 368        read_unlock(&entry->rw_lock);
 369
 370        if (!i) /* entry is not ready */
 371                return -ENODATA;
 372        
 373        for (i = 0; i < 6 && devpath->layers[i]; i++)
 374                out += sprintf(out, "%u ", devpath->layers[i]);
 375
 376        out += sprintf(out, "\n");
 377        
 378        return out - buf;
 379}
 380
 381/**
 382 * pdcspath_layer_write - This function handles extended layer modifying.
 383 * @entry: An allocated and populated pdscpath_entry struct.
 384 * @buf: The input buffer to read from.
 385 * @count: The number of bytes to be read.
 386 * 
 387 * We will call this function to change the current layer value.
 388 * Layers are to be given '.'-delimited, without brackets.
 389 * XXX beware we are far less checky WRT input data provided than for hwpath.
 390 * Potential harm can be done, since there's no way to check the validity of
 391 * the layer fields.
 392 */
 393static ssize_t
 394pdcspath_layer_write(struct pdcspath_entry *entry, const char *buf, size_t count)
 395{
 396        unsigned int layers[6]; /* device-specific info (ctlr#, unit#, ...) */
 397        unsigned short i;
 398        char in[count+1], *temp;
 399
 400        if (!entry || !buf || !count)
 401                return -EINVAL;
 402
 403        /* We'll use a local copy of buf */
 404        memset(in, 0, count+1);
 405        strncpy(in, buf, count);
 406        
 407        /* Let's clean up the target. 0 is a blank pattern */
 408        memset(&layers, 0, sizeof(layers));
 409        
 410        /* First, pick the first layer */
 411        if (unlikely(!isdigit(*in)))
 412                return -EINVAL;
 413        layers[0] = simple_strtoul(in, NULL, 10);
 414        DPRINTK("%s: layer[0]: %d\n", __func__, layers[0]);
 415        
 416        temp = in;
 417        for (i=1; ((temp = strchr(temp, '.'))) && (likely(i<6)); i++) {
 418                if (unlikely(!isdigit(*(++temp))))
 419                        return -EINVAL;
 420                layers[i] = simple_strtoul(temp, NULL, 10);
 421                DPRINTK("%s: layer[%d]: %d\n", __func__, i, layers[i]);
 422        }
 423                
 424        /* So far so good, let's get in deep */
 425        write_lock(&entry->rw_lock);
 426        
 427        /* First, overwrite the current layers with the new ones, not touching
 428           the hardware path. */
 429        memcpy(&entry->devpath.layers, &layers, sizeof(layers));
 430        
 431        /* Now, dive in. Write back to the hardware */
 432        pdcspath_store(entry);
 433        write_unlock(&entry->rw_lock);
 434        
 435        printk(KERN_INFO PDCS_PREFIX ": changed \"%s\" layers to \"%s\"\n",
 436                entry->name, buf);
 437        
 438        return count;
 439}
 440
 441/**
 442 * pdcspath_attr_show - Generic read function call wrapper.
 443 * @kobj: The kobject to get info from.
 444 * @attr: The attribute looked upon.
 445 * @buf: The output buffer.
 446 */
 447static ssize_t
 448pdcspath_attr_show(struct kobject *kobj, struct attribute *attr, char *buf)
 449{
 450        struct pdcspath_entry *entry = to_pdcspath_entry(kobj);
 451        struct pdcspath_attribute *pdcs_attr = to_pdcspath_attribute(attr);
 452        ssize_t ret = 0;
 453
 454        if (pdcs_attr->show)
 455                ret = pdcs_attr->show(entry, buf);
 456
 457        return ret;
 458}
 459
 460/**
 461 * pdcspath_attr_store - Generic write function call wrapper.
 462 * @kobj: The kobject to write info to.
 463 * @attr: The attribute to be modified.
 464 * @buf: The input buffer.
 465 * @count: The size of the buffer.
 466 */
 467static ssize_t
 468pdcspath_attr_store(struct kobject *kobj, struct attribute *attr,
 469                        const char *buf, size_t count)
 470{
 471        struct pdcspath_entry *entry = to_pdcspath_entry(kobj);
 472        struct pdcspath_attribute *pdcs_attr = to_pdcspath_attribute(attr);
 473        ssize_t ret = 0;
 474
 475        if (!capable(CAP_SYS_ADMIN))
 476                return -EACCES;
 477
 478        if (pdcs_attr->store)
 479                ret = pdcs_attr->store(entry, buf, count);
 480
 481        return ret;
 482}
 483
 484static const struct sysfs_ops pdcspath_attr_ops = {
 485        .show = pdcspath_attr_show,
 486        .store = pdcspath_attr_store,
 487};
 488
 489/* These are the two attributes of any PDC path. */
 490static PATHS_ATTR(hwpath, 0644, pdcspath_hwpath_read, pdcspath_hwpath_write);
 491static PATHS_ATTR(layer, 0644, pdcspath_layer_read, pdcspath_layer_write);
 492
 493static struct attribute *paths_subsys_attrs[] = {
 494        &paths_attr_hwpath.attr,
 495        &paths_attr_layer.attr,
 496        NULL,
 497};
 498
 499/* Specific kobject type for our PDC paths */
 500static struct kobj_type ktype_pdcspath = {
 501        .sysfs_ops = &pdcspath_attr_ops,
 502        .default_attrs = paths_subsys_attrs,
 503};
 504
 505/* We hard define the 4 types of path we expect to find */
 506static PDCSPATH_ENTRY(PDCS_ADDR_PPRI, primary);
 507static PDCSPATH_ENTRY(PDCS_ADDR_PCON, console);
 508static PDCSPATH_ENTRY(PDCS_ADDR_PALT, alternative);
 509static PDCSPATH_ENTRY(PDCS_ADDR_PKBD, keyboard);
 510
 511/* An array containing all PDC paths we will deal with */
 512static struct pdcspath_entry *pdcspath_entries[] = {
 513        &pdcspath_entry_primary,
 514        &pdcspath_entry_alternative,
 515        &pdcspath_entry_console,
 516        &pdcspath_entry_keyboard,
 517        NULL,
 518};
 519
 520
 521/* For more insight of what's going on here, refer to PDC Procedures doc,
 522 * Section PDC_STABLE */
 523
 524/**
 525 * pdcs_size_read - Stable Storage size output.
 526 * @buf: The output buffer to write to.
 527 */
 528static ssize_t pdcs_size_read(struct kobject *kobj,
 529                              struct kobj_attribute *attr,
 530                              char *buf)
 531{
 532        char *out = buf;
 533
 534        if (!buf)
 535                return -EINVAL;
 536
 537        /* show the size of the stable storage */
 538        out += sprintf(out, "%ld\n", pdcs_size);
 539
 540        return out - buf;
 541}
 542
 543/**
 544 * pdcs_auto_read - Stable Storage autoboot/search flag output.
 545 * @buf: The output buffer to write to.
 546 * @knob: The PF_AUTOBOOT or PF_AUTOSEARCH flag
 547 */
 548static ssize_t pdcs_auto_read(struct kobject *kobj,
 549                              struct kobj_attribute *attr,
 550                              char *buf, int knob)
 551{
 552        char *out = buf;
 553        struct pdcspath_entry *pathentry;
 554
 555        if (!buf)
 556                return -EINVAL;
 557
 558        /* Current flags are stored in primary boot path entry */
 559        pathentry = &pdcspath_entry_primary;
 560
 561        read_lock(&pathentry->rw_lock);
 562        out += sprintf(out, "%s\n", (pathentry->devpath.flags & knob) ?
 563                                        "On" : "Off");
 564        read_unlock(&pathentry->rw_lock);
 565
 566        return out - buf;
 567}
 568
 569/**
 570 * pdcs_autoboot_read - Stable Storage autoboot flag output.
 571 * @buf: The output buffer to write to.
 572 */
 573static ssize_t pdcs_autoboot_read(struct kobject *kobj,
 574                                  struct kobj_attribute *attr, char *buf)
 575{
 576        return pdcs_auto_read(kobj, attr, buf, PF_AUTOBOOT);
 577}
 578
 579/**
 580 * pdcs_autosearch_read - Stable Storage autoboot flag output.
 581 * @buf: The output buffer to write to.
 582 */
 583static ssize_t pdcs_autosearch_read(struct kobject *kobj,
 584                                    struct kobj_attribute *attr, char *buf)
 585{
 586        return pdcs_auto_read(kobj, attr, buf, PF_AUTOSEARCH);
 587}
 588
 589/**
 590 * pdcs_timer_read - Stable Storage timer count output (in seconds).
 591 * @buf: The output buffer to write to.
 592 *
 593 * The value of the timer field correponds to a number of seconds in powers of 2.
 594 */
 595static ssize_t pdcs_timer_read(struct kobject *kobj,
 596                               struct kobj_attribute *attr, char *buf)
 597{
 598        char *out = buf;
 599        struct pdcspath_entry *pathentry;
 600
 601        if (!buf)
 602                return -EINVAL;
 603
 604        /* Current flags are stored in primary boot path entry */
 605        pathentry = &pdcspath_entry_primary;
 606
 607        /* print the timer value in seconds */
 608        read_lock(&pathentry->rw_lock);
 609        out += sprintf(out, "%u\n", (pathentry->devpath.flags & PF_TIMER) ?
 610                                (1 << (pathentry->devpath.flags & PF_TIMER)) : 0);
 611        read_unlock(&pathentry->rw_lock);
 612
 613        return out - buf;
 614}
 615
 616/**
 617 * pdcs_osid_read - Stable Storage OS ID register output.
 618 * @buf: The output buffer to write to.
 619 */
 620static ssize_t pdcs_osid_read(struct kobject *kobj,
 621                              struct kobj_attribute *attr, char *buf)
 622{
 623        char *out = buf;
 624
 625        if (!buf)
 626                return -EINVAL;
 627
 628        out += sprintf(out, "%s dependent data (0x%.4x)\n",
 629                os_id_to_string(pdcs_osid), pdcs_osid);
 630
 631        return out - buf;
 632}
 633
 634/**
 635 * pdcs_osdep1_read - Stable Storage OS-Dependent data area 1 output.
 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 * @buf: The output buffer to write to.
 663 *
 664 * I have NFC how to interpret the content of that register ;-).
 665 */
 666static ssize_t pdcs_diagnostic_read(struct kobject *kobj,
 667                                    struct kobj_attribute *attr, char *buf)
 668{
 669        char *out = buf;
 670        u32 result;
 671
 672        if (!buf)
 673                return -EINVAL;
 674
 675        /* get diagnostic */
 676        if (pdc_stable_read(PDCS_ADDR_DIAG, &result, sizeof(result)) != PDC_OK)
 677                return -EIO;
 678
 679        out += sprintf(out, "0x%.4x\n", (result >> 16));
 680
 681        return out - buf;
 682}
 683
 684/**
 685 * pdcs_fastsize_read - Stable Storage FastSize register output.
 686 * @buf: The output buffer to write to.
 687 *
 688 * This register holds the amount of system RAM to be tested during boot sequence.
 689 */
 690static ssize_t pdcs_fastsize_read(struct kobject *kobj,
 691                                  struct kobj_attribute *attr, char *buf)
 692{
 693        char *out = buf;
 694        u32 result;
 695
 696        if (!buf)
 697                return -EINVAL;
 698
 699        /* get fast-size */
 700        if (pdc_stable_read(PDCS_ADDR_FSIZ, &result, sizeof(result)) != PDC_OK)
 701                return -EIO;
 702
 703        if ((result & 0x0F) < 0x0E)
 704                out += sprintf(out, "%d kB", (1<<(result & 0x0F))*256);
 705        else
 706                out += sprintf(out, "All");
 707        out += sprintf(out, "\n");
 708        
 709        return out - buf;
 710}
 711
 712/**
 713 * pdcs_osdep2_read - Stable Storage OS-Dependent data area 2 output.
 714 * @buf: The output buffer to write to.
 715 *
 716 * This can hold pdcs_size - 224 bytes of OS-Dependent data, when available.
 717 */
 718static ssize_t pdcs_osdep2_read(struct kobject *kobj,
 719                                struct kobj_attribute *attr, char *buf)
 720{
 721        char *out = buf;
 722        unsigned long size;
 723        unsigned short i;
 724        u32 result;
 725
 726        if (unlikely(pdcs_size <= 224))
 727                return -ENODATA;
 728
 729        size = pdcs_size - 224;
 730
 731        if (!buf)
 732                return -EINVAL;
 733
 734        for (i=0; i<size; i+=4) {
 735                if (unlikely(pdc_stable_read(PDCS_ADDR_OSD2 + i, &result,
 736                                        sizeof(result)) != PDC_OK))
 737                        return -EIO;
 738                out += sprintf(out, "0x%.8x\n", result);
 739        }
 740
 741        return out - buf;
 742}
 743
 744/**
 745 * pdcs_auto_write - This function handles autoboot/search flag modifying.
 746 * @buf: The input buffer to read from.
 747 * @count: The number of bytes to be read.
 748 * @knob: The PF_AUTOBOOT or PF_AUTOSEARCH flag
 749 * 
 750 * We will call this function to change the current autoboot flag.
 751 * We expect a precise syntax:
 752 *      \"n\" (n == 0 or 1) to toggle AutoBoot Off or On
 753 */
 754static ssize_t pdcs_auto_write(struct kobject *kobj,
 755                               struct kobj_attribute *attr, const char *buf,
 756                               size_t count, int knob)
 757{
 758        struct pdcspath_entry *pathentry;
 759        unsigned char flags;
 760        char in[count+1], *temp;
 761        char c;
 762
 763        if (!capable(CAP_SYS_ADMIN))
 764                return -EACCES;
 765
 766        if (!buf || !count)
 767                return -EINVAL;
 768
 769        /* We'll use a local copy of buf */
 770        memset(in, 0, count+1);
 771        strncpy(in, buf, count);
 772
 773        /* Current flags are stored in primary boot path entry */
 774        pathentry = &pdcspath_entry_primary;
 775        
 776        /* Be nice to the existing flag record */
 777        read_lock(&pathentry->rw_lock);
 778        flags = pathentry->devpath.flags;
 779        read_unlock(&pathentry->rw_lock);
 780        
 781        DPRINTK("%s: flags before: 0x%X\n", __func__, flags);
 782
 783        temp = skip_spaces(in);
 784
 785        c = *temp++ - '0';
 786        if ((c != 0) && (c != 1))
 787                goto parse_error;
 788        if (c == 0)
 789                flags &= ~knob;
 790        else
 791                flags |= knob;
 792        
 793        DPRINTK("%s: flags after: 0x%X\n", __func__, flags);
 794                
 795        /* So far so good, let's get in deep */
 796        write_lock(&pathentry->rw_lock);
 797        
 798        /* Change the path entry flags first */
 799        pathentry->devpath.flags = flags;
 800                
 801        /* Now, dive in. Write back to the hardware */
 802        pdcspath_store(pathentry);
 803        write_unlock(&pathentry->rw_lock);
 804        
 805        printk(KERN_INFO PDCS_PREFIX ": changed \"%s\" to \"%s\"\n",
 806                (knob & PF_AUTOBOOT) ? "autoboot" : "autosearch",
 807                (flags & knob) ? "On" : "Off");
 808        
 809        return count;
 810
 811parse_error:
 812        printk(KERN_WARNING "%s: Parse error: expect \"n\" (n == 0 or 1)\n", __func__);
 813        return -EINVAL;
 814}
 815
 816/**
 817 * pdcs_autoboot_write - This function handles autoboot flag modifying.
 818 * @buf: The input buffer to read from.
 819 * @count: The number of bytes to be read.
 820 *
 821 * We will call this function to change the current boot flags.
 822 * We expect a precise syntax:
 823 *      \"n\" (n == 0 or 1) to toggle AutoSearch Off or On
 824 */
 825static ssize_t pdcs_autoboot_write(struct kobject *kobj,
 826                                   struct kobj_attribute *attr,
 827                                   const char *buf, size_t count)
 828{
 829        return pdcs_auto_write(kobj, attr, buf, count, PF_AUTOBOOT);
 830}
 831
 832/**
 833 * pdcs_autosearch_write - This function handles autosearch flag modifying.
 834 * @buf: The input buffer to read from.
 835 * @count: The number of bytes to be read.
 836 *
 837 * We will call this function to change the current boot flags.
 838 * We expect a precise syntax:
 839 *      \"n\" (n == 0 or 1) to toggle AutoSearch Off or On
 840 */
 841static ssize_t pdcs_autosearch_write(struct kobject *kobj,
 842                                     struct kobj_attribute *attr,
 843                                     const char *buf, size_t count)
 844{
 845        return pdcs_auto_write(kobj, attr, buf, count, PF_AUTOSEARCH);
 846}
 847
 848/**
 849 * pdcs_osdep1_write - Stable Storage OS-Dependent data area 1 input.
 850 * @buf: The input buffer to read from.
 851 * @count: The number of bytes to be read.
 852 *
 853 * This can store 16 bytes of OS-Dependent data. We use a byte-by-byte
 854 * write approach. It's up to userspace to deal with it when constructing
 855 * its input buffer.
 856 */
 857static ssize_t pdcs_osdep1_write(struct kobject *kobj,
 858                                 struct kobj_attribute *attr,
 859                                 const char *buf, size_t count)
 860{
 861        u8 in[16];
 862
 863        if (!capable(CAP_SYS_ADMIN))
 864                return -EACCES;
 865
 866        if (!buf || !count)
 867                return -EINVAL;
 868
 869        if (unlikely(pdcs_osid != OS_ID_LINUX))
 870                return -EPERM;
 871
 872        if (count > 16)
 873                return -EMSGSIZE;
 874
 875        /* We'll use a local copy of buf */
 876        memset(in, 0, 16);
 877        memcpy(in, buf, count);
 878
 879        if (pdc_stable_write(PDCS_ADDR_OSD1, &in, sizeof(in)) != PDC_OK)
 880                return -EIO;
 881
 882        return count;
 883}
 884
 885/**
 886 * pdcs_osdep2_write - Stable Storage OS-Dependent data area 2 input.
 887 * @buf: The input buffer to read from.
 888 * @count: The number of bytes to be read.
 889 *
 890 * This can store pdcs_size - 224 bytes of OS-Dependent data. We use a
 891 * byte-by-byte write approach. It's up to userspace to deal with it when
 892 * constructing its input buffer.
 893 */
 894static ssize_t pdcs_osdep2_write(struct kobject *kobj,
 895                                 struct kobj_attribute *attr,
 896                                 const char *buf, size_t count)
 897{
 898        unsigned long size;
 899        unsigned short i;
 900        u8 in[4];
 901
 902        if (!capable(CAP_SYS_ADMIN))
 903                return -EACCES;
 904
 905        if (!buf || !count)
 906                return -EINVAL;
 907
 908        if (unlikely(pdcs_size <= 224))
 909                return -ENOSYS;
 910
 911        if (unlikely(pdcs_osid != OS_ID_LINUX))
 912                return -EPERM;
 913
 914        size = pdcs_size - 224;
 915
 916        if (count > size)
 917                return -EMSGSIZE;
 918
 919        /* We'll use a local copy of buf */
 920
 921        for (i=0; i<count; i+=4) {
 922                memset(in, 0, 4);
 923                memcpy(in, buf+i, (count-i < 4) ? count-i : 4);
 924                if (unlikely(pdc_stable_write(PDCS_ADDR_OSD2 + i, &in,
 925                                        sizeof(in)) != PDC_OK))
 926                        return -EIO;
 927        }
 928
 929        return count;
 930}
 931
 932/* The remaining attributes. */
 933static PDCS_ATTR(size, 0444, pdcs_size_read, NULL);
 934static PDCS_ATTR(autoboot, 0644, pdcs_autoboot_read, pdcs_autoboot_write);
 935static PDCS_ATTR(autosearch, 0644, pdcs_autosearch_read, pdcs_autosearch_write);
 936static PDCS_ATTR(timer, 0444, pdcs_timer_read, NULL);
 937static PDCS_ATTR(osid, 0444, pdcs_osid_read, NULL);
 938static PDCS_ATTR(osdep1, 0600, pdcs_osdep1_read, pdcs_osdep1_write);
 939static PDCS_ATTR(diagnostic, 0400, pdcs_diagnostic_read, NULL);
 940static PDCS_ATTR(fastsize, 0400, pdcs_fastsize_read, NULL);
 941static PDCS_ATTR(osdep2, 0600, pdcs_osdep2_read, pdcs_osdep2_write);
 942
 943static struct attribute *pdcs_subsys_attrs[] = {
 944        &pdcs_attr_size.attr,
 945        &pdcs_attr_autoboot.attr,
 946        &pdcs_attr_autosearch.attr,
 947        &pdcs_attr_timer.attr,
 948        &pdcs_attr_osid.attr,
 949        &pdcs_attr_osdep1.attr,
 950        &pdcs_attr_diagnostic.attr,
 951        &pdcs_attr_fastsize.attr,
 952        &pdcs_attr_osdep2.attr,
 953        NULL,
 954};
 955
 956static struct attribute_group pdcs_attr_group = {
 957        .attrs = pdcs_subsys_attrs,
 958};
 959
 960static struct kobject *stable_kobj;
 961static struct kset *paths_kset;
 962
 963/**
 964 * pdcs_register_pathentries - Prepares path entries kobjects for sysfs usage.
 965 * 
 966 * It creates kobjects corresponding to each path entry with nice sysfs
 967 * links to the real device. This is where the magic takes place: when
 968 * registering the subsystem attributes during module init, each kobject hereby
 969 * created will show in the sysfs tree as a folder containing files as defined
 970 * by path_subsys_attr[].
 971 */
 972static inline int __init
 973pdcs_register_pathentries(void)
 974{
 975        unsigned short i;
 976        struct pdcspath_entry *entry;
 977        int err;
 978        
 979        /* Initialize the entries rw_lock before anything else */
 980        for (i = 0; (entry = pdcspath_entries[i]); i++)
 981                rwlock_init(&entry->rw_lock);
 982
 983        for (i = 0; (entry = pdcspath_entries[i]); i++) {
 984                write_lock(&entry->rw_lock);
 985                err = pdcspath_fetch(entry);
 986                write_unlock(&entry->rw_lock);
 987
 988                if (err < 0)
 989                        continue;
 990
 991                entry->kobj.kset = paths_kset;
 992                err = kobject_init_and_add(&entry->kobj, &ktype_pdcspath, NULL,
 993                                           "%s", entry->name);
 994                if (err)
 995                        return err;
 996
 997                /* kobject is now registered */
 998                write_lock(&entry->rw_lock);
 999                entry->ready = 2;
1000                
1001                /* Add a nice symlink to the real device */
1002                if (entry->dev) {
1003                        err = sysfs_create_link(&entry->kobj, &entry->dev->kobj, "device");
1004                        WARN_ON(err);
1005                }
1006
1007                write_unlock(&entry->rw_lock);
1008                kobject_uevent(&entry->kobj, KOBJ_ADD);
1009        }
1010        
1011        return 0;
1012}
1013
1014/**
1015 * pdcs_unregister_pathentries - Routine called when unregistering the module.
1016 */
1017static inline void
1018pdcs_unregister_pathentries(void)
1019{
1020        unsigned short i;
1021        struct pdcspath_entry *entry;
1022        
1023        for (i = 0; (entry = pdcspath_entries[i]); i++) {
1024                read_lock(&entry->rw_lock);
1025                if (entry->ready >= 2)
1026                        kobject_put(&entry->kobj);
1027                read_unlock(&entry->rw_lock);
1028        }
1029}
1030
1031/*
1032 * For now we register the stable subsystem with the firmware subsystem
1033 * and the paths subsystem with the stable subsystem
1034 */
1035static int __init
1036pdc_stable_init(void)
1037{
1038        int rc = 0, error = 0;
1039        u32 result;
1040
1041        /* find the size of the stable storage */
1042        if (pdc_stable_get_size(&pdcs_size) != PDC_OK) 
1043                return -ENODEV;
1044
1045        /* make sure we have enough data */
1046        if (pdcs_size < 96)
1047                return -ENODATA;
1048
1049        printk(KERN_INFO PDCS_PREFIX " facility v%s\n", PDCS_VERSION);
1050
1051        /* get OSID */
1052        if (pdc_stable_read(PDCS_ADDR_OSID, &result, sizeof(result)) != PDC_OK)
1053                return -EIO;
1054
1055        /* the actual result is 16 bits away */
1056        pdcs_osid = (u16)(result >> 16);
1057
1058        /* For now we'll register the directory at /sys/firmware/stable */
1059        stable_kobj = kobject_create_and_add("stable", firmware_kobj);
1060        if (!stable_kobj) {
1061                rc = -ENOMEM;
1062                goto fail_firmreg;
1063        }
1064
1065        /* Don't forget the root entries */
1066        error = sysfs_create_group(stable_kobj, &pdcs_attr_group);
1067
1068        /* register the paths kset as a child of the stable kset */
1069        paths_kset = kset_create_and_add("paths", NULL, stable_kobj);
1070        if (!paths_kset) {
1071                rc = -ENOMEM;
1072                goto fail_ksetreg;
1073        }
1074
1075        /* now we create all "files" for the paths kset */
1076        if ((rc = pdcs_register_pathentries()))
1077                goto fail_pdcsreg;
1078
1079        return rc;
1080        
1081fail_pdcsreg:
1082        pdcs_unregister_pathentries();
1083        kset_unregister(paths_kset);
1084        
1085fail_ksetreg:
1086        kobject_put(stable_kobj);
1087        
1088fail_firmreg:
1089        printk(KERN_INFO PDCS_PREFIX " bailing out\n");
1090        return rc;
1091}
1092
1093static void __exit
1094pdc_stable_exit(void)
1095{
1096        pdcs_unregister_pathentries();
1097        kset_unregister(paths_kset);
1098        kobject_put(stable_kobj);
1099}
1100
1101
1102module_init(pdc_stable_init);
1103module_exit(pdc_stable_exit);
1104
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