edd.c

对于那些带有区码限制的DVD光驱

	p += scnprintf(p, left, "%u\n", info->params.num_default_cylinders);
	return (p - buf);
}

static ssize_t
edd_show_default_heads(struct edd_device *edev, char *buf)
{
	struct edd_info *info;
	char *p = buf;
	if (!edev)
		return -EINVAL;
	info = edd_dev_get_info(edev);
	if (!info || !buf)
		return -EINVAL;

	p += scnprintf(p, left, "%u\n", info->params.num_default_heads);
	return (p - buf);
}

static ssize_t
edd_show_default_sectors_per_track(struct edd_device *edev, char *buf)
{
	struct edd_info *info;
	char *p = buf;
	if (!edev)
		return -EINVAL;
	info = edd_dev_get_info(edev);
	if (!info || !buf)
		return -EINVAL;

	p += scnprintf(p, left, "%u\n", info->params.sectors_per_track);
	return (p - buf);
}

static ssize_t
edd_show_sectors(struct edd_device *edev, char *buf)
{
	struct edd_info *info;
	char *p = buf;
	if (!edev)
		return -EINVAL;
	info = edd_dev_get_info(edev);
	if (!info || !buf)
		return -EINVAL;

	p += scnprintf(p, left, "%llu\n", info->params.number_of_sectors);
	return (p - buf);
}


/*
 * Some device instances may not have all the above attributes,
 * or the attribute values may be meaningless (i.e. if
 * the device is < EDD 3.0, it won't have host_bus and interface
 * information), so don't bother making files for them.  Likewise
 * if the default_{cylinders,heads,sectors_per_track} values
 * are zero, the BIOS doesn't provide sane values, don't bother
 * creating files for them either.
 */

static int
edd_has_legacy_max_cylinder(struct edd_device *edev)
{
	struct edd_info *info;
	if (!edev)
		return 0;
	info = edd_dev_get_info(edev);
	if (!info)
		return 0;
	return info->legacy_max_cylinder > 0;
}

static int
edd_has_legacy_max_head(struct edd_device *edev)
{
	struct edd_info *info;
	if (!edev)
		return 0;
	info = edd_dev_get_info(edev);
	if (!info)
		return 0;
	return info->legacy_max_head > 0;
}

static int
edd_has_legacy_sectors_per_track(struct edd_device *edev)
{
	struct edd_info *info;
	if (!edev)
		return 0;
	info = edd_dev_get_info(edev);
	if (!info)
		return 0;
	return info->legacy_sectors_per_track > 0;
}

static int
edd_has_default_cylinders(struct edd_device *edev)
{
	struct edd_info *info;
	if (!edev)
		return 0;
	info = edd_dev_get_info(edev);
	if (!info)
		return 0;
	return info->params.num_default_cylinders > 0;
}

static int
edd_has_default_heads(struct edd_device *edev)
{
	struct edd_info *info;
	if (!edev)
		return 0;
	info = edd_dev_get_info(edev);
	if (!info)
		return 0;
	return info->params.num_default_heads > 0;
}

static int
edd_has_default_sectors_per_track(struct edd_device *edev)
{
	struct edd_info *info;
	if (!edev)
		return 0;
	info = edd_dev_get_info(edev);
	if (!info)
		return 0;
	return info->params.sectors_per_track > 0;
}

static int
edd_has_edd30(struct edd_device *edev)
{
	struct edd_info *info;
	int i, nonzero_path = 0;
	char c;

	if (!edev)
		return 0;
	info = edd_dev_get_info(edev);
	if (!info)
		return 0;

	if (!(info->params.key == 0xBEDD || info->params.key == 0xDDBE)) {
		return 0;
	}

	for (i = 30; i <= 73; i++) {
		c = *(((uint8_t *) info) + i + 4);
		if (c) {
			nonzero_path++;
			break;
		}
	}
	if (!nonzero_path) {
		return 0;
	}

	return 1;
}


static EDD_DEVICE_ATTR(raw_data, 0444, edd_show_raw_data, edd_has_edd_info);
static EDD_DEVICE_ATTR(version, 0444, edd_show_version, edd_has_edd_info);
static EDD_DEVICE_ATTR(extensions, 0444, edd_show_extensions, edd_has_edd_info);
static EDD_DEVICE_ATTR(info_flags, 0444, edd_show_info_flags, edd_has_edd_info);
static EDD_DEVICE_ATTR(sectors, 0444, edd_show_sectors, edd_has_edd_info);
static EDD_DEVICE_ATTR(legacy_max_cylinder, 0444,
                       edd_show_legacy_max_cylinder,
		       edd_has_legacy_max_cylinder);
static EDD_DEVICE_ATTR(legacy_max_head, 0444, edd_show_legacy_max_head,
		       edd_has_legacy_max_head);
static EDD_DEVICE_ATTR(legacy_sectors_per_track, 0444,
                       edd_show_legacy_sectors_per_track,
		       edd_has_legacy_sectors_per_track);
static EDD_DEVICE_ATTR(default_cylinders, 0444, edd_show_default_cylinders,
		       edd_has_default_cylinders);
static EDD_DEVICE_ATTR(default_heads, 0444, edd_show_default_heads,
		       edd_has_default_heads);
static EDD_DEVICE_ATTR(default_sectors_per_track, 0444,
		       edd_show_default_sectors_per_track,
		       edd_has_default_sectors_per_track);
static EDD_DEVICE_ATTR(interface, 0444, edd_show_interface, edd_has_edd30);
static EDD_DEVICE_ATTR(host_bus, 0444, edd_show_host_bus, edd_has_edd30);
static EDD_DEVICE_ATTR(mbr_signature, 0444, edd_show_mbr_signature, edd_has_mbr_signature);


/* These are default attributes that are added for every edd
 * device discovered.  There are none.
 */
static struct attribute * def_attrs[] = {
	NULL,
};

/* These attributes are conditional and only added for some devices. */
static struct edd_attribute * edd_attrs[] = {
	&edd_attr_raw_data,
	&edd_attr_version,
	&edd_attr_extensions,
	&edd_attr_info_flags,
	&edd_attr_sectors,
	&edd_attr_legacy_max_cylinder,
	&edd_attr_legacy_max_head,
	&edd_attr_legacy_sectors_per_track,
	&edd_attr_default_cylinders,
	&edd_attr_default_heads,
	&edd_attr_default_sectors_per_track,
	&edd_attr_interface,
	&edd_attr_host_bus,
	&edd_attr_mbr_signature,
	NULL,
};

/**
 *	edd_release - free edd structure
 *	@kobj:	kobject of edd structure
 *
 *	This is called when the refcount of the edd structure
 *	reaches 0. This should happen right after we unregister,
 *	but just in case, we use the release callback anyway.
 */

static void edd_release(struct kobject * kobj)
{
	struct edd_device * dev = to_edd_device(kobj);
	kfree(dev);
}

static struct kobj_type ktype_edd = {
	.release	= edd_release,
	.sysfs_ops	= &edd_attr_ops,
	.default_attrs	= def_attrs,
};

static decl_subsys(edd,&ktype_edd,NULL);


/**
 * edd_dev_is_type() - is this EDD device a 'type' device?
 * @edev
 * @type - a host bus or interface identifier string per the EDD spec
 *
 * Returns 1 (TRUE) if it is a 'type' device, 0 otherwise.
 */
static int
edd_dev_is_type(struct edd_device *edev, const char *type)
{
	struct edd_info *info;
	if (!edev)
		return 0;
	info = edd_dev_get_info(edev);

	if (type && info) {
		if (!strncmp(info->params.host_bus_type, type, strlen(type)) ||
		    !strncmp(info->params.interface_type, type, strlen(type)))
			return 1;
	}
	return 0;
}

/**
 * edd_get_pci_dev() - finds pci_dev that matches edev
 * @edev - edd_device
 *
 * Returns pci_dev if found, or NULL
 */
static struct pci_dev *
edd_get_pci_dev(struct edd_device *edev)
{
	struct edd_info *info = edd_dev_get_info(edev);

	if (edd_dev_is_type(edev, "PCI")) {
		return pci_find_slot(info->params.interface_path.pci.bus,
				     PCI_DEVFN(info->params.interface_path.pci.slot,
					       info->params.interface_path.pci.
					       function));
	}
	return NULL;
}

static int
edd_create_symlink_to_pcidev(struct edd_device *edev)
{

	struct pci_dev *pci_dev = edd_get_pci_dev(edev);
	if (!pci_dev)
		return 1;
	return sysfs_create_link(&edev->kobj,&pci_dev->dev.kobj,"pci_dev");
}

static inline void
edd_device_unregister(struct edd_device *edev)
{
	kobject_unregister(&edev->kobj);
}

static void edd_populate_dir(struct edd_device * edev)
{
	struct edd_attribute * attr;
	int error = 0;
	int i;

	for (i = 0; (attr = edd_attrs[i]) && !error; i++) {
		if (!attr->test ||
		    (attr->test && attr->test(edev)))
			error = sysfs_create_file(&edev->kobj,&attr->attr);
	}

	if (!error) {
		edd_create_symlink_to_pcidev(edev);
	}
}

static int
edd_device_register(struct edd_device *edev, int i)
{
	int error;

	if (!edev)
		return 1;
	edd_dev_set_info(edev, i);
	kobject_set_name(&edev->kobj, "int13_dev%02x",
			 0x80 + i);
	kobj_set_kset_s(edev,edd_subsys);
	error = kobject_register(&edev->kobj);
	if (!error)
		edd_populate_dir(edev);
	return error;
}

static inline int edd_num_devices(void)
{
	return max_t(unsigned char,
		     min_t(unsigned char, EDD_MBR_SIG_MAX, edd.mbr_signature_nr),
		     min_t(unsigned char, EDDMAXNR, edd.edd_info_nr));
}

/**
 * edd_init() - creates sysfs tree of EDD data
 */
static int __init
edd_init(void)
{
	unsigned int i;
	int rc=0;
	struct edd_device *edev;

	printk(KERN_INFO "BIOS EDD facility v%s %s, %d devices found\n",
	       EDD_VERSION, EDD_DATE, edd_num_devices());

	if (!edd_num_devices()) {
		printk(KERN_INFO "EDD information not available.\n");
		return 1;
	}

	rc = firmware_register(&edd_subsys);
	if (rc)
		return rc;

	for (i = 0; i < edd_num_devices() && !rc; i++) {
		edev = kzalloc(sizeof (*edev), GFP_KERNEL);
		if (!edev)
			return -ENOMEM;

		rc = edd_device_register(edev, i);
		if (rc) {
			kfree(edev);
			break;
		}
		edd_devices[i] = edev;
	}

	if (rc)
		firmware_unregister(&edd_subsys);
	return rc;
}

static void __exit
edd_exit(void)
{
	int i;
	struct edd_device *edev;

	for (i = 0; i < edd_num_devices(); i++) {
		if ((edev = edd_devices[i]))
			edd_device_unregister(edev);
	}
	firmware_unregister(&edd_subsys);
}

late_initcall(edd_init);
module_exit(edd_exit);