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Commit a62c24d7 authored by Dan Ehrenberg's avatar Dan Ehrenberg Committed by Brian Norris
Browse files

mtd: part: Add sysfs variable for offset of partition 



This patch makes a sysfs variable called 'offset' on each partition
which contains the offset in bytes from the beginning of the master
device that the partition starts.

Signed-off-by: default avatarDan Ehrenberg <dehrenberg@chromium.org>
Signed-off-by: default avatarBrian Norris <computersforpeace@gmail.com>
parent 727dc612

Documentation/ABI/testing/sysfs-class-mtd

+10 −0
Original line number Original line Diff line number Diff line
@@ -222,3 +222,13 @@ Description: 
		The number of blocks that are marked as reserved, if any, in

		The number of blocks that are marked as reserved, if any, in

		this partition. These are typically used to store the in-flash

		this partition. These are typically used to store the in-flash

		bad block table (BBT).

		bad block table (BBT).



What:		/sys/class/mtd/mtdX/offset

Date:		March 2015

KernelVersion:	4.1

Contact:	linux-mtd@lists.infradead.org

Description:

		For a partition, the offset of that partition from the start

		of the master device in bytes. This attribute is absent on

		main devices, so it can be used to distinguish between

		partitions and devices that aren't partitions.

drivers/mtd/mtdpart.c

+29 −0
Original line number Original line Diff line number Diff line
@@ -554,6 +554,30 @@ static struct mtd_part *allocate_partition(struct mtd_info *master, 
	return slave;

	return slave;

}

}





static ssize_t mtd_partition_offset_show(struct device *dev,

		struct device_attribute *attr, char *buf)

{

	struct mtd_info *mtd = dev_get_drvdata(dev);

	struct mtd_part *part = PART(mtd);

	return snprintf(buf, PAGE_SIZE, "%lld\n", part->offset);

}



static DEVICE_ATTR(offset, S_IRUGO, mtd_partition_offset_show, NULL);



static const struct attribute *mtd_partition_attrs[] = {

	&dev_attr_offset.attr,

	NULL

};



static int mtd_add_partition_attrs(struct mtd_part *new)

{

	int ret = sysfs_create_files(&new->mtd.dev.kobj, mtd_partition_attrs);

	if (ret)

		printk(KERN_WARNING

		       "mtd: failed to create partition attrs, err=%d\n", ret);

	return ret;

}



int mtd_add_partition(struct mtd_info *master, const char *name,

int mtd_add_partition(struct mtd_info *master, const char *name,

		      long long offset, long long length)

		      long long offset, long long length)

{

{
@@ -603,6 +627,8 @@ int mtd_add_partition(struct mtd_info *master, const char *name, 




	add_mtd_device(&new->mtd);

	add_mtd_device(&new->mtd);





	mtd_add_partition_attrs(new);



	return ret;

	return ret;

err_inv:

err_inv:

	mutex_unlock(&mtd_partitions_mutex);

	mutex_unlock(&mtd_partitions_mutex);
@@ -620,6 +646,8 @@ int mtd_del_partition(struct mtd_info *master, int partno) 
	list_for_each_entry_safe(slave, next, &mtd_partitions, list)

	list_for_each_entry_safe(slave, next, &mtd_partitions, list)

		if ((slave->master == master) &&

		if ((slave->master == master) &&

		    (slave->mtd.index == partno)) {

		    (slave->mtd.index == partno)) {

			sysfs_remove_files(&slave->mtd.dev.kobj,

					   mtd_partition_attrs);

			ret = del_mtd_device(&slave->mtd);

			ret = del_mtd_device(&slave->mtd);

			if (ret < 0)

			if (ret < 0)

				break;

				break;
@@ -663,6 +691,7 @@ int add_mtd_partitions(struct mtd_info *master, 
		mutex_unlock(&mtd_partitions_mutex);

		mutex_unlock(&mtd_partitions_mutex);





		add_mtd_device(&slave->mtd);

		add_mtd_device(&slave->mtd);

		mtd_add_partition_attrs(slave);





		cur_offset = slave->offset + slave->mtd.size;

		cur_offset = slave->offset + slave->mtd.size;

	}

	}