[PATCH v5 1/7] scsi: ufs: Add "wb_on" sysfs node to control WB on/off

Bean Huo
2020-12-16T00:08:47Z

From: Bean Huo <beanhuo@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.

Reviewed-by: Avri Altman <avri.altman@wdc.com>
Reviewed-by: Stanley Chu <stanley.chu@mediatek.com>
Signed-off-by: Bean Huo <beanhuo@micron.com>
---
drivers/scsi/ufs/ufs-sysfs.c | 41 ++++++++++++++++++++++++++++++++++++
drivers/scsi/ufs/ufshcd.c | 3 +--
drivers/scsi/ufs/ufshcd.h | 2 ++
3 files changed, 44 insertions(+), 2 deletions(-)

diff --git a/drivers/scsi/ufs/ufs-sysfs.c b/drivers/scsi/ufs/ufs-sysfs.c
index 08e72b7eef6a..f3ca3d6b82c4 100644
--- a/drivers/scsi/ufs/ufs-sysfs.c
+++ b/drivers/scsi/ufs/ufs-sysfs.c
@@ -189,6 +189,45 @@ 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 sysfs_emit(buf, "%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_CLK_SCALING, turn WB
+ * on/off will be done while clock scaling up/down.
+ */
+ 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 +235,7 @@ 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 +245,7 @@ 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 e221add25a7e..5e1dcf4de67e 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -246,7 +246,6 @@ 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);
@@ -5351,7 +5350,7 @@ 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 9bb5f0ed4124..2a97006a2c93 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)
{
--
2.17.1