linux/drivers/parisc/pdc_stable.c
Thomas Gleixner 4505153954 treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 333
Based on 1 normalized pattern(s):

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license version 2 as
  published by the free software foundation this program is
  distributed in the hope that it will be useful but without any
  warranty without even the implied warranty of merchantability or
  fitness for a particular purpose see the gnu general public license
  for more details you should have received a copy of the gnu general
  public license along with this program if not write to the free
  software foundation inc 59 temple place suite 330 boston ma 02111
  1307 usa

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-only

has been chosen to replace the boilerplate/reference in 136 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Alexios Zavras <alexios.zavras@intel.com>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190530000436.384967451@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-06-05 17:37:06 +02:00

1092 lines
30 KiB
C

// SPDX-License-Identifier: GPL-2.0-only
/*
* Interfaces to retrieve and set PDC Stable options (firmware)
*
* Copyright (C) 2005-2006 Thibaut VARENE <varenet@parisc-linux.org>
*
* DEV NOTE: the PDC Procedures reference states that:
* "A minimum of 96 bytes of Stable Storage is required. Providing more than
* 96 bytes of Stable Storage is optional [...]. Failure to provide the
* optional locations from 96 to 192 results in the loss of certain
* functionality during boot."
*
* Since locations between 96 and 192 are the various paths, most (if not
* all) PA-RISC machines should have them. Anyway, for safety reasons, the
* following code can deal with just 96 bytes of Stable Storage, and all
* sizes between 96 and 192 bytes (provided they are multiple of struct
* device_path size, eg: 128, 160 and 192) to provide full information.
* One last word: there's one path we can always count on: the primary path.
* Anything above 224 bytes is used for 'osdep2' OS-dependent storage area.
*
* The first OS-dependent area should always be available. Obviously, this is
* not true for the other one. Also bear in mind that reading/writing from/to
* osdep2 is much more expensive than from/to osdep1.
* NOTE: We do not handle the 2 bytes OS-dep area at 0x5D, nor the first
* 2 bytes of storage available right after OSID. That's a total of 4 bytes
* sacrificed: -ETOOLAZY :P
*
* The current policy wrt file permissions is:
* - write: root only
* - read: (reading triggers PDC calls) ? root only : everyone
* The rationale is that PDC calls could hog (DoS) the machine.
*
* TODO:
* - timer/fastsize write calls
*/
#undef PDCS_DEBUG
#ifdef PDCS_DEBUG
#define DPRINTK(fmt, args...) printk(KERN_DEBUG fmt, ## args)
#else
#define DPRINTK(fmt, args...)
#endif
#include <linux/module.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/capability.h>
#include <linux/ctype.h>
#include <linux/sysfs.h>
#include <linux/kobject.h>
#include <linux/device.h>
#include <linux/errno.h>
#include <linux/spinlock.h>
#include <asm/pdc.h>
#include <asm/page.h>
#include <linux/uaccess.h>
#include <asm/hardware.h>
#define PDCS_VERSION "0.30"
#define PDCS_PREFIX "PDC Stable Storage"
#define PDCS_ADDR_PPRI 0x00
#define PDCS_ADDR_OSID 0x40
#define PDCS_ADDR_OSD1 0x48
#define PDCS_ADDR_DIAG 0x58
#define PDCS_ADDR_FSIZ 0x5C
#define PDCS_ADDR_PCON 0x60
#define PDCS_ADDR_PALT 0x80
#define PDCS_ADDR_PKBD 0xA0
#define PDCS_ADDR_OSD2 0xE0
MODULE_AUTHOR("Thibaut VARENE <varenet@parisc-linux.org>");
MODULE_DESCRIPTION("sysfs interface to HP PDC Stable Storage data");
MODULE_LICENSE("GPL");
MODULE_VERSION(PDCS_VERSION);
/* holds Stable Storage size. Initialized once and for all, no lock needed */
static unsigned long pdcs_size __read_mostly;
/* holds OS ID. Initialized once and for all, hopefully to 0x0006 */
static u16 pdcs_osid __read_mostly;
/* This struct defines what we need to deal with a parisc pdc path entry */
struct pdcspath_entry {
rwlock_t rw_lock; /* to protect path entry access */
short ready; /* entry record is valid if != 0 */
unsigned long addr; /* entry address in stable storage */
char *name; /* entry name */
struct device_path devpath; /* device path in parisc representation */
struct device *dev; /* corresponding device */
struct kobject kobj;
};
struct pdcspath_attribute {
struct attribute attr;
ssize_t (*show)(struct pdcspath_entry *entry, char *buf);
ssize_t (*store)(struct pdcspath_entry *entry, const char *buf, size_t count);
};
#define PDCSPATH_ENTRY(_addr, _name) \
struct pdcspath_entry pdcspath_entry_##_name = { \
.ready = 0, \
.addr = _addr, \
.name = __stringify(_name), \
};
#define PDCS_ATTR(_name, _mode, _show, _store) \
struct kobj_attribute pdcs_attr_##_name = { \
.attr = {.name = __stringify(_name), .mode = _mode}, \
.show = _show, \
.store = _store, \
};
#define PATHS_ATTR(_name, _mode, _show, _store) \
struct pdcspath_attribute paths_attr_##_name = { \
.attr = {.name = __stringify(_name), .mode = _mode}, \
.show = _show, \
.store = _store, \
};
#define to_pdcspath_attribute(_attr) container_of(_attr, struct pdcspath_attribute, attr)
#define to_pdcspath_entry(obj) container_of(obj, struct pdcspath_entry, kobj)
/**
* pdcspath_fetch - This function populates the path entry structs.
* @entry: A pointer to an allocated pdcspath_entry.
*
* The general idea is that you don't read from the Stable Storage every time
* you access the files provided by the facilities. We store a copy of the
* content of the stable storage WRT various paths in these structs. We read
* these structs when reading the files, and we will write to these structs when
* writing to the files, and only then write them back to the Stable Storage.
*
* This function expects to be called with @entry->rw_lock write-hold.
*/
static int
pdcspath_fetch(struct pdcspath_entry *entry)
{
struct device_path *devpath;
if (!entry)
return -EINVAL;
devpath = &entry->devpath;
DPRINTK("%s: fetch: 0x%p, 0x%p, addr: 0x%lx\n", __func__,
entry, devpath, entry->addr);
/* addr, devpath and count must be word aligned */
if (pdc_stable_read(entry->addr, devpath, sizeof(*devpath)) != PDC_OK)
return -EIO;
/* Find the matching device.
NOTE: hardware_path overlays with device_path, so the nice cast can
be used */
entry->dev = hwpath_to_device((struct hardware_path *)devpath);
entry->ready = 1;
DPRINTK("%s: device: 0x%p\n", __func__, entry->dev);
return 0;
}
/**
* pdcspath_store - This function writes a path to stable storage.
* @entry: A pointer to an allocated pdcspath_entry.
*
* It can be used in two ways: either by passing it a preset devpath struct
* containing an already computed hardware path, or by passing it a device
* pointer, from which it'll find out the corresponding hardware path.
* For now we do not handle the case where there's an error in writing to the
* Stable Storage area, so you'd better not mess up the data :P
*
* This function expects to be called with @entry->rw_lock write-hold.
*/
static void
pdcspath_store(struct pdcspath_entry *entry)
{
struct device_path *devpath;
BUG_ON(!entry);
devpath = &entry->devpath;
/* We expect the caller to set the ready flag to 0 if the hardware
path struct provided is invalid, so that we know we have to fill it.
First case, we don't have a preset hwpath... */
if (!entry->ready) {
/* ...but we have a device, map it */
BUG_ON(!entry->dev);
device_to_hwpath(entry->dev, (struct hardware_path *)devpath);
}
/* else, we expect the provided hwpath to be valid. */
DPRINTK("%s: store: 0x%p, 0x%p, addr: 0x%lx\n", __func__,
entry, devpath, entry->addr);
/* addr, devpath and count must be word aligned */
if (pdc_stable_write(entry->addr, devpath, sizeof(*devpath)) != PDC_OK)
WARN(1, KERN_ERR "%s: an error occurred when writing to PDC.\n"
"It is likely that the Stable Storage data has been corrupted.\n"
"Please check it carefully upon next reboot.\n", __func__);
/* kobject is already registered */
entry->ready = 2;
DPRINTK("%s: device: 0x%p\n", __func__, entry->dev);
}
/**
* pdcspath_hwpath_read - This function handles hardware path pretty printing.
* @entry: An allocated and populated pdscpath_entry struct.
* @buf: The output buffer to write to.
*
* We will call this function to format the output of the hwpath attribute file.
*/
static ssize_t
pdcspath_hwpath_read(struct pdcspath_entry *entry, char *buf)
{
char *out = buf;
struct device_path *devpath;
short i;
if (!entry || !buf)
return -EINVAL;
read_lock(&entry->rw_lock);
devpath = &entry->devpath;
i = entry->ready;
read_unlock(&entry->rw_lock);
if (!i) /* entry is not ready */
return -ENODATA;
for (i = 0; i < 6; i++) {
if (devpath->bc[i] >= 128)
continue;
out += sprintf(out, "%u/", (unsigned char)devpath->bc[i]);
}
out += sprintf(out, "%u\n", (unsigned char)devpath->mod);
return out - buf;
}
/**
* pdcspath_hwpath_write - This function handles hardware path modifying.
* @entry: An allocated and populated pdscpath_entry struct.
* @buf: The input buffer to read from.
* @count: The number of bytes to be read.
*
* We will call this function to change the current hardware path.
* Hardware paths are to be given '/'-delimited, without brackets.
* We make sure that the provided path actually maps to an existing
* device, BUT nothing would prevent some foolish user to set the path to some
* PCI bridge or even a CPU...
* A better work around would be to make sure we are at the end of a device tree
* for instance, but it would be IMHO beyond the simple scope of that driver.
* The aim is to provide a facility. Data correctness is left to userland.
*/
static ssize_t
pdcspath_hwpath_write(struct pdcspath_entry *entry, const char *buf, size_t count)
{
struct hardware_path hwpath;
unsigned short i;
char in[64], *temp;
struct device *dev;
int ret;
if (!entry || !buf || !count)
return -EINVAL;
/* We'll use a local copy of buf */
count = min_t(size_t, count, sizeof(in)-1);
strncpy(in, buf, count);
in[count] = '\0';
/* Let's clean up the target. 0xff is a blank pattern */
memset(&hwpath, 0xff, sizeof(hwpath));
/* First, pick the mod field (the last one of the input string) */
if (!(temp = strrchr(in, '/')))
return -EINVAL;
hwpath.mod = simple_strtoul(temp+1, NULL, 10);
in[temp-in] = '\0'; /* truncate the remaining string. just precaution */
DPRINTK("%s: mod: %d\n", __func__, hwpath.mod);
/* Then, loop for each delimiter, making sure we don't have too many.
we write the bc fields in a down-top way. No matter what, we stop
before writing the last field. If there are too many fields anyway,
then the user is a moron and it'll be caught up later when we'll
check the consistency of the given hwpath. */
for (i=5; ((temp = strrchr(in, '/'))) && (temp-in > 0) && (likely(i)); i--) {
hwpath.bc[i] = simple_strtoul(temp+1, NULL, 10);
in[temp-in] = '\0';
DPRINTK("%s: bc[%d]: %d\n", __func__, i, hwpath.bc[i]);
}
/* Store the final field */
hwpath.bc[i] = simple_strtoul(in, NULL, 10);
DPRINTK("%s: bc[%d]: %d\n", __func__, i, hwpath.bc[i]);
/* Now we check that the user isn't trying to lure us */
if (!(dev = hwpath_to_device((struct hardware_path *)&hwpath))) {
printk(KERN_WARNING "%s: attempt to set invalid \"%s\" "
"hardware path: %s\n", __func__, entry->name, buf);
return -EINVAL;
}
/* So far so good, let's get in deep */
write_lock(&entry->rw_lock);
entry->ready = 0;
entry->dev = dev;
/* Now, dive in. Write back to the hardware */
pdcspath_store(entry);
/* Update the symlink to the real device */
sysfs_remove_link(&entry->kobj, "device");
write_unlock(&entry->rw_lock);
ret = sysfs_create_link(&entry->kobj, &entry->dev->kobj, "device");
WARN_ON(ret);
printk(KERN_INFO PDCS_PREFIX ": changed \"%s\" path to \"%s\"\n",
entry->name, buf);
return count;
}
/**
* pdcspath_layer_read - Extended layer (eg. SCSI ids) pretty printing.
* @entry: An allocated and populated pdscpath_entry struct.
* @buf: The output buffer to write to.
*
* We will call this function to format the output of the layer attribute file.
*/
static ssize_t
pdcspath_layer_read(struct pdcspath_entry *entry, char *buf)
{
char *out = buf;
struct device_path *devpath;
short i;
if (!entry || !buf)
return -EINVAL;
read_lock(&entry->rw_lock);
devpath = &entry->devpath;
i = entry->ready;
read_unlock(&entry->rw_lock);
if (!i) /* entry is not ready */
return -ENODATA;
for (i = 0; i < 6 && devpath->layers[i]; i++)
out += sprintf(out, "%u ", devpath->layers[i]);
out += sprintf(out, "\n");
return out - buf;
}
/**
* pdcspath_layer_write - This function handles extended layer modifying.
* @entry: An allocated and populated pdscpath_entry struct.
* @buf: The input buffer to read from.
* @count: The number of bytes to be read.
*
* We will call this function to change the current layer value.
* Layers are to be given '.'-delimited, without brackets.
* XXX beware we are far less checky WRT input data provided than for hwpath.
* Potential harm can be done, since there's no way to check the validity of
* the layer fields.
*/
static ssize_t
pdcspath_layer_write(struct pdcspath_entry *entry, const char *buf, size_t count)
{
unsigned int layers[6]; /* device-specific info (ctlr#, unit#, ...) */
unsigned short i;
char in[64], *temp;
if (!entry || !buf || !count)
return -EINVAL;
/* We'll use a local copy of buf */
count = min_t(size_t, count, sizeof(in)-1);
strncpy(in, buf, count);
in[count] = '\0';
/* Let's clean up the target. 0 is a blank pattern */
memset(&layers, 0, sizeof(layers));
/* First, pick the first layer */
if (unlikely(!isdigit(*in)))
return -EINVAL;
layers[0] = simple_strtoul(in, NULL, 10);
DPRINTK("%s: layer[0]: %d\n", __func__, layers[0]);
temp = in;
for (i=1; ((temp = strchr(temp, '.'))) && (likely(i<6)); i++) {
if (unlikely(!isdigit(*(++temp))))
return -EINVAL;
layers[i] = simple_strtoul(temp, NULL, 10);
DPRINTK("%s: layer[%d]: %d\n", __func__, i, layers[i]);
}
/* So far so good, let's get in deep */
write_lock(&entry->rw_lock);
/* First, overwrite the current layers with the new ones, not touching
the hardware path. */
memcpy(&entry->devpath.layers, &layers, sizeof(layers));
/* Now, dive in. Write back to the hardware */
pdcspath_store(entry);
write_unlock(&entry->rw_lock);
printk(KERN_INFO PDCS_PREFIX ": changed \"%s\" layers to \"%s\"\n",
entry->name, buf);
return count;
}
/**
* pdcspath_attr_show - Generic read function call wrapper.
* @kobj: The kobject to get info from.
* @attr: The attribute looked upon.
* @buf: The output buffer.
*/
static ssize_t
pdcspath_attr_show(struct kobject *kobj, struct attribute *attr, char *buf)
{
struct pdcspath_entry *entry = to_pdcspath_entry(kobj);
struct pdcspath_attribute *pdcs_attr = to_pdcspath_attribute(attr);
ssize_t ret = 0;
if (pdcs_attr->show)
ret = pdcs_attr->show(entry, buf);
return ret;
}
/**
* pdcspath_attr_store - Generic write function call wrapper.
* @kobj: The kobject to write info to.
* @attr: The attribute to be modified.
* @buf: The input buffer.
* @count: The size of the buffer.
*/
static ssize_t
pdcspath_attr_store(struct kobject *kobj, struct attribute *attr,
const char *buf, size_t count)
{
struct pdcspath_entry *entry = to_pdcspath_entry(kobj);
struct pdcspath_attribute *pdcs_attr = to_pdcspath_attribute(attr);
ssize_t ret = 0;
if (!capable(CAP_SYS_ADMIN))
return -EACCES;
if (pdcs_attr->store)
ret = pdcs_attr->store(entry, buf, count);
return ret;
}
static const struct sysfs_ops pdcspath_attr_ops = {
.show = pdcspath_attr_show,
.store = pdcspath_attr_store,
};
/* These are the two attributes of any PDC path. */
static PATHS_ATTR(hwpath, 0644, pdcspath_hwpath_read, pdcspath_hwpath_write);
static PATHS_ATTR(layer, 0644, pdcspath_layer_read, pdcspath_layer_write);
static struct attribute *paths_subsys_attrs[] = {
&paths_attr_hwpath.attr,
&paths_attr_layer.attr,
NULL,
};
/* Specific kobject type for our PDC paths */
static struct kobj_type ktype_pdcspath = {
.sysfs_ops = &pdcspath_attr_ops,
.default_attrs = paths_subsys_attrs,
};
/* We hard define the 4 types of path we expect to find */
static PDCSPATH_ENTRY(PDCS_ADDR_PPRI, primary);
static PDCSPATH_ENTRY(PDCS_ADDR_PCON, console);
static PDCSPATH_ENTRY(PDCS_ADDR_PALT, alternative);
static PDCSPATH_ENTRY(PDCS_ADDR_PKBD, keyboard);
/* An array containing all PDC paths we will deal with */
static struct pdcspath_entry *pdcspath_entries[] = {
&pdcspath_entry_primary,
&pdcspath_entry_alternative,
&pdcspath_entry_console,
&pdcspath_entry_keyboard,
NULL,
};
/* For more insight of what's going on here, refer to PDC Procedures doc,
* Section PDC_STABLE */
/**
* pdcs_size_read - Stable Storage size output.
* @buf: The output buffer to write to.
*/
static ssize_t pdcs_size_read(struct kobject *kobj,
struct kobj_attribute *attr,
char *buf)
{
char *out = buf;
if (!buf)
return -EINVAL;
/* show the size of the stable storage */
out += sprintf(out, "%ld\n", pdcs_size);
return out - buf;
}
/**
* pdcs_auto_read - Stable Storage autoboot/search flag output.
* @buf: The output buffer to write to.
* @knob: The PF_AUTOBOOT or PF_AUTOSEARCH flag
*/
static ssize_t pdcs_auto_read(struct kobject *kobj,
struct kobj_attribute *attr,
char *buf, int knob)
{
char *out = buf;
struct pdcspath_entry *pathentry;
if (!buf)
return -EINVAL;
/* Current flags are stored in primary boot path entry */
pathentry = &pdcspath_entry_primary;
read_lock(&pathentry->rw_lock);
out += sprintf(out, "%s\n", (pathentry->devpath.flags & knob) ?
"On" : "Off");
read_unlock(&pathentry->rw_lock);
return out - buf;
}
/**
* pdcs_autoboot_read - Stable Storage autoboot flag output.
* @buf: The output buffer to write to.
*/
static ssize_t pdcs_autoboot_read(struct kobject *kobj,
struct kobj_attribute *attr, char *buf)
{
return pdcs_auto_read(kobj, attr, buf, PF_AUTOBOOT);
}
/**
* pdcs_autosearch_read - Stable Storage autoboot flag output.
* @buf: The output buffer to write to.
*/
static ssize_t pdcs_autosearch_read(struct kobject *kobj,
struct kobj_attribute *attr, char *buf)
{
return pdcs_auto_read(kobj, attr, buf, PF_AUTOSEARCH);
}
/**
* pdcs_timer_read - Stable Storage timer count output (in seconds).
* @buf: The output buffer to write to.
*
* The value of the timer field correponds to a number of seconds in powers of 2.
*/
static ssize_t pdcs_timer_read(struct kobject *kobj,
struct kobj_attribute *attr, char *buf)
{
char *out = buf;
struct pdcspath_entry *pathentry;
if (!buf)
return -EINVAL;
/* Current flags are stored in primary boot path entry */
pathentry = &pdcspath_entry_primary;
/* print the timer value in seconds */
read_lock(&pathentry->rw_lock);
out += sprintf(out, "%u\n", (pathentry->devpath.flags & PF_TIMER) ?
(1 << (pathentry->devpath.flags & PF_TIMER)) : 0);
read_unlock(&pathentry->rw_lock);
return out - buf;
}
/**
* pdcs_osid_read - Stable Storage OS ID register output.
* @buf: The output buffer to write to.
*/
static ssize_t pdcs_osid_read(struct kobject *kobj,
struct kobj_attribute *attr, char *buf)
{
char *out = buf;
if (!buf)
return -EINVAL;
out += sprintf(out, "%s dependent data (0x%.4x)\n",
os_id_to_string(pdcs_osid), pdcs_osid);
return out - buf;
}
/**
* pdcs_osdep1_read - Stable Storage OS-Dependent data area 1 output.
* @buf: The output buffer to write to.
*
* This can hold 16 bytes of OS-Dependent data.
*/
static ssize_t pdcs_osdep1_read(struct kobject *kobj,
struct kobj_attribute *attr, char *buf)
{
char *out = buf;
u32 result[4];
if (!buf)
return -EINVAL;
if (pdc_stable_read(PDCS_ADDR_OSD1, &result, sizeof(result)) != PDC_OK)
return -EIO;
out += sprintf(out, "0x%.8x\n", result[0]);
out += sprintf(out, "0x%.8x\n", result[1]);
out += sprintf(out, "0x%.8x\n", result[2]);
out += sprintf(out, "0x%.8x\n", result[3]);
return out - buf;
}
/**
* pdcs_diagnostic_read - Stable Storage Diagnostic register output.
* @buf: The output buffer to write to.
*
* I have NFC how to interpret the content of that register ;-).
*/
static ssize_t pdcs_diagnostic_read(struct kobject *kobj,
struct kobj_attribute *attr, char *buf)
{
char *out = buf;
u32 result;
if (!buf)
return -EINVAL;
/* get diagnostic */
if (pdc_stable_read(PDCS_ADDR_DIAG, &result, sizeof(result)) != PDC_OK)
return -EIO;
out += sprintf(out, "0x%.4x\n", (result >> 16));
return out - buf;
}
/**
* pdcs_fastsize_read - Stable Storage FastSize register output.
* @buf: The output buffer to write to.
*
* This register holds the amount of system RAM to be tested during boot sequence.
*/
static ssize_t pdcs_fastsize_read(struct kobject *kobj,
struct kobj_attribute *attr, char *buf)
{
char *out = buf;
u32 result;
if (!buf)
return -EINVAL;
/* get fast-size */
if (pdc_stable_read(PDCS_ADDR_FSIZ, &result, sizeof(result)) != PDC_OK)
return -EIO;
if ((result & 0x0F) < 0x0E)
out += sprintf(out, "%d kB", (1<<(result & 0x0F))*256);
else
out += sprintf(out, "All");
out += sprintf(out, "\n");
return out - buf;
}
/**
* pdcs_osdep2_read - Stable Storage OS-Dependent data area 2 output.
* @buf: The output buffer to write to.
*
* This can hold pdcs_size - 224 bytes of OS-Dependent data, when available.
*/
static ssize_t pdcs_osdep2_read(struct kobject *kobj,
struct kobj_attribute *attr, char *buf)
{
char *out = buf;
unsigned long size;
unsigned short i;
u32 result;
if (unlikely(pdcs_size <= 224))
return -ENODATA;
size = pdcs_size - 224;
if (!buf)
return -EINVAL;
for (i=0; i<size; i+=4) {
if (unlikely(pdc_stable_read(PDCS_ADDR_OSD2 + i, &result,
sizeof(result)) != PDC_OK))
return -EIO;
out += sprintf(out, "0x%.8x\n", result);
}
return out - buf;
}
/**
* pdcs_auto_write - This function handles autoboot/search flag modifying.
* @buf: The input buffer to read from.
* @count: The number of bytes to be read.
* @knob: The PF_AUTOBOOT or PF_AUTOSEARCH flag
*
* We will call this function to change the current autoboot flag.
* We expect a precise syntax:
* \"n\" (n == 0 or 1) to toggle AutoBoot Off or On
*/
static ssize_t pdcs_auto_write(struct kobject *kobj,
struct kobj_attribute *attr, const char *buf,
size_t count, int knob)
{
struct pdcspath_entry *pathentry;
unsigned char flags;
char in[8], *temp;
char c;
if (!capable(CAP_SYS_ADMIN))
return -EACCES;
if (!buf || !count)
return -EINVAL;
/* We'll use a local copy of buf */
count = min_t(size_t, count, sizeof(in)-1);
strncpy(in, buf, count);
in[count] = '\0';
/* Current flags are stored in primary boot path entry */
pathentry = &pdcspath_entry_primary;
/* Be nice to the existing flag record */
read_lock(&pathentry->rw_lock);
flags = pathentry->devpath.flags;
read_unlock(&pathentry->rw_lock);
DPRINTK("%s: flags before: 0x%X\n", __func__, flags);
temp = skip_spaces(in);
c = *temp++ - '0';
if ((c != 0) && (c != 1))
goto parse_error;
if (c == 0)
flags &= ~knob;
else
flags |= knob;
DPRINTK("%s: flags after: 0x%X\n", __func__, flags);
/* So far so good, let's get in deep */
write_lock(&pathentry->rw_lock);
/* Change the path entry flags first */
pathentry->devpath.flags = flags;
/* Now, dive in. Write back to the hardware */
pdcspath_store(pathentry);
write_unlock(&pathentry->rw_lock);
printk(KERN_INFO PDCS_PREFIX ": changed \"%s\" to \"%s\"\n",
(knob & PF_AUTOBOOT) ? "autoboot" : "autosearch",
(flags & knob) ? "On" : "Off");
return count;
parse_error:
printk(KERN_WARNING "%s: Parse error: expect \"n\" (n == 0 or 1)\n", __func__);
return -EINVAL;
}
/**
* pdcs_autoboot_write - This function handles autoboot flag modifying.
* @buf: The input buffer to read from.
* @count: The number of bytes to be read.
*
* We will call this function to change the current boot flags.
* We expect a precise syntax:
* \"n\" (n == 0 or 1) to toggle AutoSearch Off or On
*/
static ssize_t pdcs_autoboot_write(struct kobject *kobj,
struct kobj_attribute *attr,
const char *buf, size_t count)
{
return pdcs_auto_write(kobj, attr, buf, count, PF_AUTOBOOT);
}
/**
* pdcs_autosearch_write - This function handles autosearch flag modifying.
* @buf: The input buffer to read from.
* @count: The number of bytes to be read.
*
* We will call this function to change the current boot flags.
* We expect a precise syntax:
* \"n\" (n == 0 or 1) to toggle AutoSearch Off or On
*/
static ssize_t pdcs_autosearch_write(struct kobject *kobj,
struct kobj_attribute *attr,
const char *buf, size_t count)
{
return pdcs_auto_write(kobj, attr, buf, count, PF_AUTOSEARCH);
}
/**
* pdcs_osdep1_write - Stable Storage OS-Dependent data area 1 input.
* @buf: The input buffer to read from.
* @count: The number of bytes to be read.
*
* This can store 16 bytes of OS-Dependent data. We use a byte-by-byte
* write approach. It's up to userspace to deal with it when constructing
* its input buffer.
*/
static ssize_t pdcs_osdep1_write(struct kobject *kobj,
struct kobj_attribute *attr,
const char *buf, size_t count)
{
u8 in[16];
if (!capable(CAP_SYS_ADMIN))
return -EACCES;
if (!buf || !count)
return -EINVAL;
if (unlikely(pdcs_osid != OS_ID_LINUX))
return -EPERM;
if (count > 16)
return -EMSGSIZE;
/* We'll use a local copy of buf */
memset(in, 0, 16);
memcpy(in, buf, count);
if (pdc_stable_write(PDCS_ADDR_OSD1, &in, sizeof(in)) != PDC_OK)
return -EIO;
return count;
}
/**
* pdcs_osdep2_write - Stable Storage OS-Dependent data area 2 input.
* @buf: The input buffer to read from.
* @count: The number of bytes to be read.
*
* This can store pdcs_size - 224 bytes of OS-Dependent data. We use a
* byte-by-byte write approach. It's up to userspace to deal with it when
* constructing its input buffer.
*/
static ssize_t pdcs_osdep2_write(struct kobject *kobj,
struct kobj_attribute *attr,
const char *buf, size_t count)
{
unsigned long size;
unsigned short i;
u8 in[4];
if (!capable(CAP_SYS_ADMIN))
return -EACCES;
if (!buf || !count)
return -EINVAL;
if (unlikely(pdcs_size <= 224))
return -ENOSYS;
if (unlikely(pdcs_osid != OS_ID_LINUX))
return -EPERM;
size = pdcs_size - 224;
if (count > size)
return -EMSGSIZE;
/* We'll use a local copy of buf */
for (i=0; i<count; i+=4) {
memset(in, 0, 4);
memcpy(in, buf+i, (count-i < 4) ? count-i : 4);
if (unlikely(pdc_stable_write(PDCS_ADDR_OSD2 + i, &in,
sizeof(in)) != PDC_OK))
return -EIO;
}
return count;
}
/* The remaining attributes. */
static PDCS_ATTR(size, 0444, pdcs_size_read, NULL);
static PDCS_ATTR(autoboot, 0644, pdcs_autoboot_read, pdcs_autoboot_write);
static PDCS_ATTR(autosearch, 0644, pdcs_autosearch_read, pdcs_autosearch_write);
static PDCS_ATTR(timer, 0444, pdcs_timer_read, NULL);
static PDCS_ATTR(osid, 0444, pdcs_osid_read, NULL);
static PDCS_ATTR(osdep1, 0600, pdcs_osdep1_read, pdcs_osdep1_write);
static PDCS_ATTR(diagnostic, 0400, pdcs_diagnostic_read, NULL);
static PDCS_ATTR(fastsize, 0400, pdcs_fastsize_read, NULL);
static PDCS_ATTR(osdep2, 0600, pdcs_osdep2_read, pdcs_osdep2_write);
static struct attribute *pdcs_subsys_attrs[] = {
&pdcs_attr_size.attr,
&pdcs_attr_autoboot.attr,
&pdcs_attr_autosearch.attr,
&pdcs_attr_timer.attr,
&pdcs_attr_osid.attr,
&pdcs_attr_osdep1.attr,
&pdcs_attr_diagnostic.attr,
&pdcs_attr_fastsize.attr,
&pdcs_attr_osdep2.attr,
NULL,
};
static const struct attribute_group pdcs_attr_group = {
.attrs = pdcs_subsys_attrs,
};
static struct kobject *stable_kobj;
static struct kset *paths_kset;
/**
* pdcs_register_pathentries - Prepares path entries kobjects for sysfs usage.
*
* It creates kobjects corresponding to each path entry with nice sysfs
* links to the real device. This is where the magic takes place: when
* registering the subsystem attributes during module init, each kobject hereby
* created will show in the sysfs tree as a folder containing files as defined
* by path_subsys_attr[].
*/
static inline int __init
pdcs_register_pathentries(void)
{
unsigned short i;
struct pdcspath_entry *entry;
int err;
/* Initialize the entries rw_lock before anything else */
for (i = 0; (entry = pdcspath_entries[i]); i++)
rwlock_init(&entry->rw_lock);
for (i = 0; (entry = pdcspath_entries[i]); i++) {
write_lock(&entry->rw_lock);
err = pdcspath_fetch(entry);
write_unlock(&entry->rw_lock);
if (err < 0)
continue;
entry->kobj.kset = paths_kset;
err = kobject_init_and_add(&entry->kobj, &ktype_pdcspath, NULL,
"%s", entry->name);
if (err)
return err;
/* kobject is now registered */
write_lock(&entry->rw_lock);
entry->ready = 2;
write_unlock(&entry->rw_lock);
/* Add a nice symlink to the real device */
if (entry->dev) {
err = sysfs_create_link(&entry->kobj, &entry->dev->kobj, "device");
WARN_ON(err);
}
kobject_uevent(&entry->kobj, KOBJ_ADD);
}
return 0;
}
/**
* pdcs_unregister_pathentries - Routine called when unregistering the module.
*/
static inline void
pdcs_unregister_pathentries(void)
{
unsigned short i;
struct pdcspath_entry *entry;
for (i = 0; (entry = pdcspath_entries[i]); i++) {
read_lock(&entry->rw_lock);
if (entry->ready >= 2)
kobject_put(&entry->kobj);
read_unlock(&entry->rw_lock);
}
}
/*
* For now we register the stable subsystem with the firmware subsystem
* and the paths subsystem with the stable subsystem
*/
static int __init
pdc_stable_init(void)
{
int rc = 0, error = 0;
u32 result;
/* find the size of the stable storage */
if (pdc_stable_get_size(&pdcs_size) != PDC_OK)
return -ENODEV;
/* make sure we have enough data */
if (pdcs_size < 96)
return -ENODATA;
printk(KERN_INFO PDCS_PREFIX " facility v%s\n", PDCS_VERSION);
/* get OSID */
if (pdc_stable_read(PDCS_ADDR_OSID, &result, sizeof(result)) != PDC_OK)
return -EIO;
/* the actual result is 16 bits away */
pdcs_osid = (u16)(result >> 16);
/* For now we'll register the directory at /sys/firmware/stable */
stable_kobj = kobject_create_and_add("stable", firmware_kobj);
if (!stable_kobj) {
rc = -ENOMEM;
goto fail_firmreg;
}
/* Don't forget the root entries */
error = sysfs_create_group(stable_kobj, &pdcs_attr_group);
/* register the paths kset as a child of the stable kset */
paths_kset = kset_create_and_add("paths", NULL, stable_kobj);
if (!paths_kset) {
rc = -ENOMEM;
goto fail_ksetreg;
}
/* now we create all "files" for the paths kset */
if ((rc = pdcs_register_pathentries()))
goto fail_pdcsreg;
return rc;
fail_pdcsreg:
pdcs_unregister_pathentries();
kset_unregister(paths_kset);
fail_ksetreg:
kobject_put(stable_kobj);
fail_firmreg:
printk(KERN_INFO PDCS_PREFIX " bailing out\n");
return rc;
}
static void __exit
pdc_stable_exit(void)
{
pdcs_unregister_pathentries();
kset_unregister(paths_kset);
kobject_put(stable_kobj);
}
module_init(pdc_stable_init);
module_exit(pdc_stable_exit);