scsi: ufs: Add "wb_on" sysfs node to control WB on/off

Currently UFS WriteBooster driver uses clock scaling up/down to set WB
on/off. For the platforms which don'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.

Link: https://lore.kernel.org/r/20210119163847.20165-2-huobean@gmail.com
Reviewed-by: Avri Altman <avri.altman@wdc.com>
Reviewed-by: Stanley Chu <stanley.chu@mediatek.com>
Signed-off-by: Bean Huo <beanhuo@micron.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

diff --git a/drivers/scsi/ufs/ufs-sysfs.c b/drivers/scsi/ufs/ufs-sysfs.c
index c092f24..76db859 100644 (file)
--- a/drivers/scsi/ufs/ufs-sysfs.c
+++ b/drivers/scsi/ufs/ufs-sysfs.c
@@ -209,6 +209,50 @@ out:
        return ret ? ret : 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_wb_allowed(hba) || 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 (kstrtouint(buf, 0, &wb_enable))
+               return -EINVAL;
+
+       if (wb_enable != 0 && wb_enable != 1)
+               return -EINVAL;
+
+       down(&hba->host_sem);
+       if (!ufshcd_is_user_access_allowed(hba)) {
+               res = -EBUSY;
+               goto out;
+       }
+
+       pm_runtime_get_sync(hba->dev);
+       res = ufshcd_wb_ctrl(hba, wb_enable);
+       pm_runtime_put_sync(hba->dev);
+out:
+       up(&hba->host_sem);
+       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);
@@ -216,6 +260,7 @@ 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,
@@ -225,6 +270,7 @@ 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 a4631ca..f3e0a87 100644 (file)
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -249,7 +249,6 @@ 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);
@@ -5416,7 +5415,7 @@ out:
                                __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 a5c6084..fc2e0c1 100644 (file)
--- a/drivers/scsi/ufs/ufshcd.h
+++ b/drivers/scsi/ufs/ufshcd.h
@@ -1093,6 +1093,8 @@ 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)
 {