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Diffstat (limited to 'drivers/mtd/mtdcore.c')
-rw-r--r--drivers/mtd/mtdcore.c57
1 files changed, 56 insertions, 1 deletions
diff --git a/drivers/mtd/mtdcore.c b/drivers/mtd/mtdcore.c
index c837507..5757307 100644
--- a/drivers/mtd/mtdcore.c
+++ b/drivers/mtd/mtdcore.c
@@ -250,6 +250,43 @@ static ssize_t mtd_name_show(struct device *dev,
}
static DEVICE_ATTR(name, S_IRUGO, mtd_name_show, NULL);
+static ssize_t mtd_ecc_strength_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->ecc_strength);
+}
+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,
@@ -260,6 +297,8 @@ static struct attribute *mtd_attrs[] = {
&dev_attr_oobsize.attr,
&dev_attr_numeraseregions.attr,
&dev_attr_name.attr,
+ &dev_attr_ecc_strength.attr,
+ &dev_attr_bitflip_threshold.attr,
NULL,
};
@@ -322,6 +361,10 @@ int add_mtd_device(struct mtd_info *mtd)
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
@@ -757,12 +800,24 @@ EXPORT_SYMBOL_GPL(mtd_get_unmapped_area);
int mtd_read(struct mtd_info *mtd, loff_t from, size_t len, size_t *retlen,
u_char *buf)
{
+ int ret_code;
*retlen = 0;
if (from < 0 || from > mtd->size || len > mtd->size - from)
return -EINVAL;
if (!len)
return 0;
- return mtd->_read(mtd, from, len, retlen, buf);
+
+ /*
+ * In the absence of an error, drivers return a non-negative integer
+ * representing the maximum number of bitflips that were corrected on
+ * any one ecc region (if applicable; zero otherwise).
+ */
+ ret_code = mtd->_read(mtd, from, len, retlen, buf);
+ if (unlikely(ret_code < 0))
+ return ret_code;
+ if (mtd->ecc_strength == 0)
+ return 0; /* device lacks ecc */
+ return ret_code >= mtd->bitflip_threshold ? -EUCLEAN : 0;
}
EXPORT_SYMBOL_GPL(mtd_read);
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