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scsi: ufs: change msleep to usleep_range 

This patch is to change msleep() to usleep_range() based on
Documentation/timers/timers-howto.txt. It suggests using usleep_range()
for small msec(1ms - 20ms) since msleep() will often sleep longer than
desired value.

After changing, booting time will be 5ms-10ms faster than before.  I
tested this change on two different platforms, one has 5ms faster, another
one is about 10ms. I think this is different on different platform.

Actually, from UFS host side, 1ms-5ms delay is already sufficient for its
initialization of the local UIC layer.

Fixes: 7a3e97b0dc ([SCSI] ufshcd: UFS Host controller driver)
Signed-off-by: Bean Huo <beanhuo@micron.com>
Acked-by: Stanley Chu <stanley.chu@mediatek.com>
Reviewed-by: Avri Altman <avri.altman@wdc.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
alistair/sunxi64-5.4-dsi
Bean Huo 2019-07-15 11:21:10 +00:00 committed by Martin K. Petersen
parent 70a51d8c53
commit 838c1efc6a
1 changed files with 2 additions and 8 deletions
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10
drivers/scsi/ufs/ufshcd.c
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@ -4226,12 +4226,6 @@ static int ufshcd_hba_execute_hce(struct ufs_hba *hba)
{
int retry;
/*
* msleep of 1 and 5 used in this function might result in msleep(20),
* but it was necessary to send the UFS FPGA to reset mode during
* development and testing of this driver. msleep can be changed to
* mdelay and retry count can be reduced based on the controller.
*/
if (!ufshcd_is_hba_active(hba))
/* change controller state to "reset state" */
ufshcd_hba_stop(hba, true);
@ -4254,7 +4248,7 @@ static int ufshcd_hba_execute_hce(struct ufs_hba *hba)
* instruction might be read back.
* This delay can be changed based on the controller.
*/
msleep(1);
usleep_range(1000, 1100);
/* wait for the host controller to complete initialization */
retry = 10;
@ -4266,7 +4260,7 @@ static int ufshcd_hba_execute_hce(struct ufs_hba *hba)
"Controller enable failed\n");
return -EIO;
}
msleep(5);
usleep_range(5000, 5100);
}
/* enable UIC related interrupts */