[PATCH v4 4/8] scsi: ufs: introduce common delay function

[Stanley Chu <stanley.chu@mediatek.com>]

Introduce common delay function to collect all delay requirements
to simplify driver and take choices of udelay and usleep_range into
consideration.

Signed-off-by: Stanley Chu <stanley.chu@mediatek.com>
---
 drivers/scsi/ufs/ufshcd.c | 27 ++++++++++++++++++---------
 drivers/scsi/ufs/ufshcd.h |  1 +
 2 files changed, 19 insertions(+), 9 deletions(-)

diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index b4988b9ee36c..ce65d321a73f 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -597,6 +597,18 @@ static void ufshcd_print_pwr_info(struct ufs_hba *hba)
 		 hba->pwr_info.hs_rate);
 }
 
+void ufshcd_wait_us(unsigned long us, unsigned long tolerance, bool can_sleep)
+{
+	if (!us)
+		return;
+
+	if (us < 10 || !can_sleep)
+		udelay(us);
+	else
+		usleep_range(us, us + tolerance);
+}
+EXPORT_SYMBOL_GPL(ufshcd_wait_us);
+
 /*
  * ufshcd_wait_for_register - wait for register value to change
  * @hba - per-adapter interface
@@ -620,10 +632,7 @@ int ufshcd_wait_for_register(struct ufs_hba *hba, u32 reg, u32 mask,
 	val = val & mask;
 
 	while ((ufshcd_readl(hba, reg) & mask) != val) {
-		if (can_sleep)
-			usleep_range(interval_us, interval_us + 50);
-		else
-			udelay(interval_us);
+		ufshcd_wait_us(interval_us, 50, can_sleep);
 		if (time_after(jiffies, timeout)) {
 			if ((ufshcd_readl(hba, reg) & mask) != val)
 				err = -ETIMEDOUT;
@@ -3565,7 +3574,7 @@ static inline void ufshcd_add_delay_before_dme_cmd(struct ufs_hba *hba)
 	}
 
 	/* allow sleep for extra 50us if needed */
-	usleep_range(min_sleep_time_us, min_sleep_time_us + 50);
+	ufshcd_wait_us(min_sleep_time_us, 50, true);
 }
 
 /**
@@ -4289,7 +4298,7 @@ int ufshcd_hba_enable(struct ufs_hba *hba)
 	 * instruction might be read back.
 	 * This delay can be changed based on the controller.
 	 */
-	usleep_range(1000, 1100);
+	ufshcd_wait_us(1000, 100, true);
 
 	/* wait for the host controller to complete initialization */
 	retry = 10;
@@ -4301,7 +4310,7 @@ int ufshcd_hba_enable(struct ufs_hba *hba)
 				"Controller enable failed\n");
 			return -EIO;
 		}
-		usleep_range(5000, 5100);
+		ufshcd_wait_us(5000, 100, true);
 	}
 
 	/* enable UIC related interrupts */
@@ -6224,7 +6233,7 @@ static int ufshcd_abort(struct scsi_cmnd *cmd)
 			reg = ufshcd_readl(hba, REG_UTP_TRANSFER_REQ_DOOR_BELL);
 			if (reg & (1 << tag)) {
 				/* sleep for max. 200us to stabilize */
-				usleep_range(100, 200);
+				ufshcd_wait_us(100, 100, true);
 				continue;
 			}
 			/* command completed already */
@@ -7783,7 +7792,7 @@ static void ufshcd_vreg_set_lpm(struct ufs_hba *hba)
 	 */
 	if (!ufshcd_is_link_active(hba) &&
 	    hba->dev_quirks & UFS_DEVICE_QUIRK_DELAY_BEFORE_LPM)
-		usleep_range(2000, 2100);
+		ufshcd_wait_us(2000, 100, true);
 
 	/*
 	 * If UFS device is either in UFS_Sleep turn off VCC rail to save some
diff --git a/drivers/scsi/ufs/ufshcd.h b/drivers/scsi/ufs/ufshcd.h
index fec004cd8054..4683e7bf6640 100644
--- a/drivers/scsi/ufs/ufshcd.h
+++ b/drivers/scsi/ufs/ufshcd.h
@@ -781,6 +781,7 @@ int ufshcd_init(struct ufs_hba * , void __iomem * , unsigned int);
 int ufshcd_make_hba_operational(struct ufs_hba *hba);
 void ufshcd_remove(struct ufs_hba *);
 int ufshcd_uic_hibern8_exit(struct ufs_hba *hba);
+void ufshcd_wait_us(unsigned long us, unsigned long tolerance, bool can_sleep);
 int ufshcd_wait_for_register(struct ufs_hba *hba, u32 reg, u32 mask,
 				u32 val, unsigned long interval_us,
 				unsigned long timeout_ms, bool can_sleep);
-- 
2.18.0