pdc_stable.c

linux 内核源代码

	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.
 * @kset: An allocated and populated struct kset. We don't use it tho.
 * @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 kset *kset, const char *buf, size_t count, int knob)
{
	struct pdcspath_entry *pathentry;
	unsigned char flags;
	char in[count+1], *temp;
	char c;

	if (!capable(CAP_SYS_ADMIN))
		return -EACCES;

	if (!kset || !buf || !count)
		return -EINVAL;

	/* We'll use a local copy of buf */
	memset(in, 0, count+1);
	strncpy(in, buf, count);

	/* 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 = in;
	
	while (*temp && isspace(*temp))
		temp++;
	
	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.
 * @kset: An allocated and populated struct kset. We don't use it tho.
 * @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 inline ssize_t
pdcs_autoboot_write(struct kset *kset, const char *buf, size_t count)
{
	return pdcs_auto_write(kset, buf, count, PF_AUTOBOOT);
}

/**
 * pdcs_autosearch_write - This function handles autosearch flag modifying.
 * @kset: An allocated and populated struct kset. We don't use it tho.
 * @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 inline ssize_t
pdcs_autosearch_write(struct kset *kset, const char *buf, size_t count)
{
	return pdcs_auto_write(kset, buf, count, PF_AUTOSEARCH);
}

/**
 * pdcs_osdep1_write - Stable Storage OS-Dependent data area 1 input.
 * @kset: An allocated and populated struct kset. We don't use it tho.
 * @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 kset *kset, const char *buf, size_t count)
{
	u8 in[16];

	if (!capable(CAP_SYS_ADMIN))
		return -EACCES;

	if (!kset || !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.
 * @kset: An allocated and populated struct kset. We don't use it tho.
 * @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 kset *kset, const char *buf, size_t count)
{
	unsigned long size;
	unsigned short i;
	u8 in[4];

	if (!capable(CAP_SYS_ADMIN))
		return -EACCES;

	if (!kset || !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 subsys_attribute *pdcs_subsys_attrs[] = {
	&pdcs_attr_size,
	&pdcs_attr_autoboot,
	&pdcs_attr_autosearch,
	&pdcs_attr_timer,
	&pdcs_attr_osid,
	&pdcs_attr_osdep1,
	&pdcs_attr_diagnostic,
	&pdcs_attr_fastsize,
	&pdcs_attr_osdep2,
	NULL,
};

static decl_subsys(paths, &ktype_pdcspath, NULL);
static decl_subsys(stable, NULL, NULL);

/**
 * 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;

		if ((err = kobject_set_name(&entry->kobj, "%s", entry->name)))
			return err;
		kobj_set_kset_s(entry, paths_subsys);
		if ((err = kobject_register(&entry->kobj)))
			return err;
		
		/* kobject is now registered */
		write_lock(&entry->rw_lock);
		entry->ready = 2;
		
		/* Add a nice symlink to the real device */
		if (entry->dev) {
			err = sysfs_create_link(&entry->kobj, &entry->dev->kobj, "device");
			WARN_ON(err);
		}

		write_unlock(&entry->rw_lock);
	}
	
	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_unregister(&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)
{
	struct subsys_attribute *attr;
	int i, 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 stable subsys within this driver */
	if ((rc = firmware_register(&stable_subsys)))
		goto fail_firmreg;

	/* Don't forget the root entries */
	for (i = 0; (attr = pdcs_subsys_attrs[i]) && !error; i++)
		if (attr->show)
			error = subsys_create_file(&stable_subsys, attr);
	
	/* register the paths subsys as a subsystem of stable subsys */
	kobj_set_kset_s(&paths_subsys, stable_subsys);
	if ((rc = subsystem_register(&paths_subsys)))
		goto fail_subsysreg;

	/* now we create all "files" for the paths subsys */
	if ((rc = pdcs_register_pathentries()))
		goto fail_pdcsreg;

	return rc;
	
fail_pdcsreg:
	pdcs_unregister_pathentries();
	subsystem_unregister(&paths_subsys);
	
fail_subsysreg:
	firmware_unregister(&stable_subsys);
	
fail_firmreg:
	printk(KERN_INFO PDCS_PREFIX " bailing out\n");
	return rc;
}

static void __exit
pdc_stable_exit(void)
{
	pdcs_unregister_pathentries();
	subsystem_unregister(&paths_subsys);

	firmware_unregister(&stable_subsys);
}


module_init(pdc_stable_init);
module_exit(pdc_stable_exit);