Root/drivers/parisc/pdc_stable.c

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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