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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 <[email protected]>
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 <[email protected]>");
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 const 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);