On 2020-12-06 18:13, Bean Huo wrote:
From: Bean Huo <bean...@micron.com>

Currently UFS WriteBooster driver uses clock scaling up/down to set
WB on/off, for the platform which doesn't support UFSHCD_CAP_CLK_SCALING,
WB will be always on. Provide a sysfs attribute to enable/disable WB
during runtime. Write 1/0 to "wb_on" sysfs node to enable/disable UFS WB.

Signed-off-by: Bean Huo <bean...@micron.com>
---
 drivers/scsi/ufs/ufs-sysfs.c | 40 ++++++++++++++++++++++++++++++++++++
 drivers/scsi/ufs/ufshcd.c    |  3 +--
 drivers/scsi/ufs/ufshcd.h    |  2 ++
 3 files changed, 43 insertions(+), 2 deletions(-)

diff --git a/drivers/scsi/ufs/ufs-sysfs.c b/drivers/scsi/ufs/ufs-sysfs.c
index 08e72b7eef6a..b3bf7fca00e5 100644
--- a/drivers/scsi/ufs/ufs-sysfs.c
+++ b/drivers/scsi/ufs/ufs-sysfs.c
@@ -189,6 +189,44 @@ static ssize_t auto_hibern8_store(struct device *dev,
        return count;
 }

+static ssize_t wb_on_show(struct device *dev, struct device_attribute *attr,
+                         char *buf)
+{
+       struct ufs_hba *hba = dev_get_drvdata(dev);
+
+       return scnprintf(buf, PAGE_SIZE, "%d\n", hba->wb_enabled);
+}
+
+static ssize_t wb_on_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_enable;
+       ssize_t res;
+
+       if (ufshcd_is_clkscaling_supported(hba)) {
+               /* If the platform supports UFSHCD_CAP_AUTO_BKOPS_SUSPEND, turn
+                * WB on/off will be done while clock scaling up/down.
+                */

Double check comment line format?

+               dev_warn(dev, "To control WB through wb_on is not allowed!\n");
+               return -EOPNOTSUPP;
+       }
+       if (!ufshcd_is_wb_allowed(hba))
+               return -EOPNOTSUPP;
+
+       if (kstrtouint(buf, 0, &wb_enable))
+               return -EINVAL;
+
+       if (wb_enable != 0 && wb_enable != 1)
+               return -EINVAL;
+
+       pm_runtime_get_sync(hba->dev);
+       res = ufshcd_wb_ctrl(hba, wb_enable);
+       pm_runtime_put_sync(hba->dev);
+
+       return res < 0 ? res : count;
+}
+
 static DEVICE_ATTR_RW(rpm_lvl);
 static DEVICE_ATTR_RO(rpm_target_dev_state);
 static DEVICE_ATTR_RO(rpm_target_link_state);
@@ -196,6 +234,7 @@ static DEVICE_ATTR_RW(spm_lvl);
 static DEVICE_ATTR_RO(spm_target_dev_state);
 static DEVICE_ATTR_RO(spm_target_link_state);
 static DEVICE_ATTR_RW(auto_hibern8);
+static DEVICE_ATTR_RW(wb_on);

 static struct attribute *ufs_sysfs_ufshcd_attrs[] = {
        &dev_attr_rpm_lvl.attr,
@@ -205,6 +244,7 @@ static struct attribute *ufs_sysfs_ufshcd_attrs[] = {
        &dev_attr_spm_target_dev_state.attr,
        &dev_attr_spm_target_link_state.attr,
        &dev_attr_auto_hibern8.attr,
+       &dev_attr_wb_on.attr,
        NULL
 };

diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index 92d433d5f3ca..30332592e624 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -247,7 +247,6 @@ static inline int ufshcd_config_vreg_hpm(struct
ufs_hba *hba,
 static int ufshcd_try_to_abort_task(struct ufs_hba *hba, int tag);
 static int ufshcd_wb_buf_flush_enable(struct ufs_hba *hba);
 static int ufshcd_wb_buf_flush_disable(struct ufs_hba *hba);
-static int ufshcd_wb_ctrl(struct ufs_hba *hba, bool enable);
static int ufshcd_wb_toggle_flush_during_h8(struct ufs_hba *hba, bool set); static inline void ufshcd_wb_toggle_flush(struct ufs_hba *hba, bool enable);
 static void ufshcd_hba_vreg_set_lpm(struct ufs_hba *hba);
@@ -5307,7 +5306,7 @@ static void
ufshcd_bkops_exception_event_handler(struct ufs_hba *hba)
                                __func__, err);
 }

-static int ufshcd_wb_ctrl(struct ufs_hba *hba, bool enable)
+int ufshcd_wb_ctrl(struct ufs_hba *hba, bool enable)
 {
        int ret;
        u8 index;
diff --git a/drivers/scsi/ufs/ufshcd.h b/drivers/scsi/ufs/ufshcd.h
index 61344c49c2cc..c61584dff74a 100644
--- a/drivers/scsi/ufs/ufshcd.h
+++ b/drivers/scsi/ufs/ufshcd.h
@@ -1068,6 +1068,8 @@ int ufshcd_exec_raw_upiu_cmd(struct ufs_hba *hba,
                             u8 *desc_buff, int *buff_len,
                             enum query_opcode desc_op);

+int ufshcd_wb_ctrl(struct ufs_hba *hba, bool enable);
+
 /* Wrapper functions for safely calling variant operations */
 static inline const char *ufshcd_get_var_name(struct ufs_hba *hba)
 {

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