[PATCH v3 03/10] ubi: Expose max erase counter for fastmap in sysfs

Rickard Andersson
2024-10-11T13:01:20Z

Since the fastmap area has its own wear levelling it is valuable to
provide a max erase counter value specifically for that area.

Reviewed-by: Zhihao Cheng <chengzhihao1@huawei.com>
Signed-off-by: Rickard Andersson <rickard.andersson@axis.com>
---
drivers/mtd/ubi/build.c | 43 +++++++++++++++++++++++++++++++++++++++++
1 file changed, 43 insertions(+)

diff --git a/drivers/mtd/ubi/build.c b/drivers/mtd/ubi/build.c
index 1c531d623a62..a5a2e6e3be38 100644
--- a/drivers/mtd/ubi/build.c
+++ b/drivers/mtd/ubi/build.c
@@ -134,6 +134,8 @@ static struct device_attribute dev_max_ec =
static struct device_attribute dev_mean_ec =
__ATTR(mean_ec, S_IRUGO, dev_attribute_show, NULL);
#ifdef CONFIG_MTD_UBI_FASTMAP
+static struct device_attribute dev_max_ec_fastmap =
+ __ATTR(max_ec_fastmap, S_IRUGO, dev_attribute_show, NULL);
static struct device_attribute dev_mean_ec_fastmap =
__ATTR(mean_ec_fastmap, S_IRUGO, dev_attribute_show, NULL);
#endif
@@ -384,6 +386,44 @@ static int ubi_calc_mean_ec(struct ubi_device *ubi, int start_peb, int end_peb)
return mean_ec;
}

+/**
+ * ubi_calc_max_ec_fastmap - calculate max erase counter value.
+ * @ubi: UBI device description object
+ * @start_peb: First PEB in the range
+ * @end_peb: End PEB in the half-open range
+ *
+ * Returns the max erase counter value that can be found in the range.
+ * Range is half-open i.e end_peb is not actually included.
+ */
+#ifdef CONFIG_MTD_UBI_FASTMAP
+static int ubi_calc_max_ec(struct ubi_device *ubi, int start_peb, int end_peb)
+{
+ struct ubi_wl_entry *wl;
+ int peb;
+ int max_ec = 0;
+
+ for (peb = start_peb; peb < end_peb; peb++) {
+ int err;
+
+ err = ubi_io_is_bad(ubi, peb);
+ if (err)
+ continue;
+
+ spin_lock(&ubi->wl_lock);
+
+ wl = ubi->lookuptbl[peb];
+ if (wl) {
+ if (max_ec < wl->ec)
+ max_ec = wl->ec;
+ }
+
+ spin_unlock(&ubi->wl_lock);
+ }
+
+ return max_ec;
+}
+#endif
+
/* "Show" method for files in '/<sysfs>/class/ubi/ubiX/' */
static ssize_t dev_attribute_show(struct device *dev,
struct device_attribute *attr, char *buf)
@@ -416,6 +456,8 @@ static ssize_t dev_attribute_show(struct device *dev,
else if (attr == &dev_mean_ec)
ret = sprintf(buf, "%d\n", ubi_calc_mean_ec(ubi, 0, ubi->peb_count));
#ifdef CONFIG_MTD_UBI_FASTMAP
+ else if (attr == &dev_max_ec_fastmap)
+ ret = sprintf(buf, "%d\n", ubi_calc_max_ec(ubi, 0, UBI_FM_MAX_START));
else if (attr == &dev_mean_ec_fastmap)
ret = sprintf(buf, "%d\n", ubi_calc_mean_ec(ubi, 0, UBI_FM_MAX_START));
#endif
@@ -447,6 +489,7 @@ static struct attribute *ubi_dev_attrs[] = {
&dev_max_ec.attr,
&dev_mean_ec.attr,
#ifdef CONFIG_MTD_UBI_FASTMAP
+ &dev_max_ec_fastmap.attr,
&dev_mean_ec_fastmap.attr,
#endif
&dev_reserved_for_bad.attr,