mtd: bitflip_threshold added to mtd_info and sysfs
An element 'bitflip_threshold' is added to struct mtd_info, and also exposed as
a read/write variable in sysfs. This will be used to determine whether or not
mtd_read() returns -EUCLEAN or 0 (absent a hard error). If the driver leaves it
as zero, mtd will set it to a default value of ecc_strength.
This v2 adds the line that propagates bitflip_threshold from the master to the
partitions - thanks Ivan¹.
¹ http://lists.infradead.org/pipermail/linux-mtd/2012-April/040900.html
Signed-off-by: Mike Dunn <mikedunn@newsguy.com>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
diff --git a/drivers/mtd/mtdcore.c b/drivers/mtd/mtdcore.c
index 090e849..6a7cba1 100644
--- a/drivers/mtd/mtdcore.c
+++ b/drivers/mtd/mtdcore.c
@@ -259,6 +259,34 @@
}
static DEVICE_ATTR(ecc_strength, S_IRUGO, mtd_ecc_strength_show, NULL);
+static ssize_t mtd_bitflip_threshold_show(struct device *dev,
+ struct device_attribute *attr,
+ char *buf)
+{
+ struct mtd_info *mtd = dev_get_drvdata(dev);
+
+ return snprintf(buf, PAGE_SIZE, "%u\n", mtd->bitflip_threshold);
+}
+
+static ssize_t mtd_bitflip_threshold_store(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct mtd_info *mtd = dev_get_drvdata(dev);
+ unsigned int bitflip_threshold;
+ int retval;
+
+ retval = kstrtouint(buf, 0, &bitflip_threshold);
+ if (retval)
+ return retval;
+
+ mtd->bitflip_threshold = bitflip_threshold;
+ return count;
+}
+static DEVICE_ATTR(bitflip_threshold, S_IRUGO | S_IWUSR,
+ mtd_bitflip_threshold_show,
+ mtd_bitflip_threshold_store);
+
static struct attribute *mtd_attrs[] = {
&dev_attr_type.attr,
&dev_attr_flags.attr,
@@ -270,6 +298,7 @@
&dev_attr_numeraseregions.attr,
&dev_attr_name.attr,
&dev_attr_ecc_strength.attr,
+ &dev_attr_bitflip_threshold.attr,
NULL,
};
@@ -332,6 +361,10 @@
mtd->index = i;
mtd->usecount = 0;
+ /* default value if not set by driver */
+ if (mtd->bitflip_threshold == 0)
+ mtd->bitflip_threshold = mtd->ecc_strength;
+
if (is_power_of_2(mtd->erasesize))
mtd->erasesize_shift = ffs(mtd->erasesize) - 1;
else