There are three flags that control Write Booster Feature:
1. WB ON/OFF
2. WB Hibern Flush ON/OFF (implicitly)
3. WB Flush ON/OFF (explicit)
In the case of "Hibern Flush", one of the conditions for flush WB buffer is
that avail_wb_buff < wb_flush_threshold.
As we know, different users have different requirements for power
consumption and performance. Therefore, we need the ability to manually
set wb_flush_threshold, so that users can easily and flexibly adjust
the wb_flush_threshold value, thereby achieving a balance between power
consumption and performance.
So the sysfs attribute that controls this is necessary.
The meaning of wb_flush_threshold is the percentage of WB's total size,
such as 1 representing 10%, 2 representing 20%, and so on.
Signed-off-by: Lu Hongfei <[email protected]>
---
The modifications made compared to the previous version are as follows:
1. Changed %d into %u since the wb_flush_threshold is unsigned.
2. Removed the check for enabling WB in wb_flush_threshold_store.
3. Using UFS_WB_BUF_REMAIN_PERCENT(100) instead of '10', which made it easier to read.
drivers/ufs/core/ufs-sysfs.c | 33 +++++++++++++++++++++++++++++++++
1 file changed, 33 insertions(+)
diff --git a/drivers/ufs/core/ufs-sysfs.c b/drivers/ufs/core/ufs-sysfs.c
index cdf3d5f2b77b..258afee2f958
--- a/drivers/ufs/core/ufs-sysfs.c
+++ b/drivers/ufs/core/ufs-sysfs.c
@@ -298,6 +298,37 @@ static ssize_t enable_wb_buf_flush_store(struct device *dev,
return res < 0 ? res : count;
}
+static ssize_t wb_flush_threshold_show(struct device *dev,
+ struct device_attribute *attr,
+ char *buf)
+{
+ struct ufs_hba *hba = dev_get_drvdata(dev);
+
+ return sysfs_emit(buf, "%u\n", hba->vps->wb_flush_threshold);
+}
+
+static ssize_t wb_flush_threshold_store(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct ufs_hba *hba = dev_get_drvdata(dev);
+ unsigned int wb_flush_threshold;
+
+ if (kstrtouint(buf, 0, &wb_flush_threshold))
+ return -EINVAL;
+
+ /* The range of values for wb_flush_threshold is (0,10] */
+ if (wb_flush_threshold > UFS_WB_BUF_REMAIN_PERCENT(100) ||
+ wb_flush_threshold <= 0) {
+ dev_err(dev, "The value of wb_flush_threshold is invalid!\n");
+ return -EINVAL;
+ }
+
+ hba->vps->wb_flush_threshold = wb_flush_threshold;
+
+ return count;
+}
+
static DEVICE_ATTR_RW(rpm_lvl);
static DEVICE_ATTR_RO(rpm_target_dev_state);
static DEVICE_ATTR_RO(rpm_target_link_state);
@@ -307,6 +338,7 @@ static DEVICE_ATTR_RO(spm_target_link_state);
static DEVICE_ATTR_RW(auto_hibern8);
static DEVICE_ATTR_RW(wb_on);
static DEVICE_ATTR_RW(enable_wb_buf_flush);
+static DEVICE_ATTR_RW(wb_flush_threshold);
static struct attribute *ufs_sysfs_ufshcd_attrs[] = {
&dev_attr_rpm_lvl.attr,
@@ -318,6 +350,7 @@ static struct attribute *ufs_sysfs_ufshcd_attrs[] = {
&dev_attr_auto_hibern8.attr,
&dev_attr_wb_on.attr,
&dev_attr_enable_wb_buf_flush.attr,
+ &dev_attr_wb_flush_threshold.attr,
NULL
};
--
2.39.0