>
> 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 <luhongfei@xxxxxxxx>
> ---
> The modifications made compared to the previous version are as follows:
> 1. Using 'wb_flush_threshold == 0' insted of 'wb_flush_threshold <= 0'.
>
> drivers/ufs/core/ufs-sysfs.c | 33 +++++++++++++++++++++++++++++++++
> 1 file changed, 33 insertions(+)
You are missing sysfs documentation.
>
> diff --git a/drivers/ufs/core/ufs-sysfs.c b/drivers/ufs/core/ufs-sysfs.c index
> cdf3d5f2b77b..347207f4e8ee
> --- 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;
Maybe also make note if wb not supported:
if (!ufshcd_is_wb_allowed(hba) {
dev_info(dev, "It is not allowed to configure WB buf flushing!\n");
return -EOPNOTSUPP;
}
Thanks,
Avri
> +
> + /* 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
