// 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
* pdc_module_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 pdc_module_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 pdc_module_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 pdc_module_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 pdc_module_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 pdc_module_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->path.bc[i] < 0)
continue;
out += sprintf(out, "%d/", devpath->path.bc[i]);
}
out += sprintf(out, "%u\n", (unsigned char)devpath->path.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);
strscpy(in, buf, count + 1);
/* 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.path.bc[i]);
}
/* Store the final field */
hwpath.bc[i] = simple_strtoul(in, NULL, 10);
DPRINTK("%s: bc[%d]: %d\n", __func__, i, hwpath.path.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 pdc_module_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);
strscpy(in, buf, count + 1);
/* 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,
};
ATTRIBUTE_GROUPS(paths_subsys);
/* Specific kobject type for our PDC paths */
static struct kobj_type ktype_pdcspath = {
.sysfs_ops = &pdcspath_attr_ops,
.default_groups = paths_subsys_groups,
};
/* 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.
* @kobj: The kobject used to share data with userspace.
* @attr: The kobject attributes.
* @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.
* @kobj: The kobject used to share data with userspace.
* @attr: The kobject attributes.
* @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.path.flags & knob) ?
"On" : "Off");
read_unlock(&pathentry->rw_lock);
return out - buf;
}
/**
* pdcs_autoboot_read - Stable Storage autoboot flag output.
* @kobj: The kobject used to share data with userspace.
* @attr: The kobject attributes.
* @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.
* @kobj: The kobject used to share data with userspace.
* @attr: The kobject attributes.
* @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).
* @kobj: The kobject used to share data with userspace.
* @attr: The kobject attributes.
* @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.path.flags & PF_TIMER) ?
(1 << (pathentry->devpath.path.flags & PF_TIMER)) : 0);
read_unlock(&pathentry->rw_lock);
return out - buf;
}
/**
* pdcs_osid_read - Stable Storage OS ID register output.
* @kobj: The kobject used to share data with userspace.
* @attr: The kobject attributes.
* @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.
* @kobj: The kobject used to share data with userspace.
* @attr: The kobject attributes.
* @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.
* @kobj: The kobject used to share data with userspace.
* @attr: The kobject attributes.
* @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.
* @kobj: The kobject used to share data with userspace.
* @attr: The kobject attributes.
* @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.
* @kobj: The kobject used to share data with userspace.
* @attr: The kobject attributes.
* @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.
* @kobj: The kobject used to share data with userspace.
* @attr: The kobject attributes.
* @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);
strscpy(in, buf, count + 1);
/* 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.path.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.path.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.
* @kobj: The kobject used to share data with userspace.
* @attr: The kobject attributes.
* @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.
* @kobj: The kobject used to share data with userspace.
* @attr: The kobject attributes.
* @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.
* @kobj: The kobject used to share data with userspace.
* @attr: The kobject attributes.
* @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.
* @kobj: The kobject used to share data with userspace.
* @attr: The kobject attributes.
* @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) {
kobject_put(&entry->kobj);
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;
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);
if (error) {
rc = -ENOMEM;
goto fail_ksetreg;
}
/* 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);