From 1cbadd0c331fb151fafc698bf2ecc35122953715 Mon Sep 17 00:00:00 2001 From: Can Guo Date: Mon, 10 Feb 2020 19:40:50 -0800 Subject: [PATCH] scsi: ufs-qcom: Delay specific time before gate ref clk After enter hibern8, as UFS JEDEC ver 3.0 requires, a specific gating wait time is required before disable the device reference clock. If it is not specified, use the old delay. Link: https://lore.kernel.org/r/1581392451-28743-8-git-send-email-cang@codeaurora.org Reviewed-by: Asutosh Das Reviewed-by: Hongwu Su Signed-off-by: Can Guo Signed-off-by: Martin K. Petersen --- drivers/scsi/ufs/ufs-qcom.c | 22 +++++++++++++++++++--- 1 file changed, 19 insertions(+), 3 deletions(-) diff --git a/drivers/scsi/ufs/ufs-qcom.c b/drivers/scsi/ufs/ufs-qcom.c index 2800a47d9e6d..8339050f0af2 100644 --- a/drivers/scsi/ufs/ufs-qcom.c +++ b/drivers/scsi/ufs/ufs-qcom.c @@ -843,11 +843,27 @@ static void ufs_qcom_dev_ref_clk_ctrl(struct ufs_qcom_host *host, bool enable) /* * If we are here to disable this clock it might be immediately * after entering into hibern8 in which case we need to make - * sure that device ref_clk is active at least 1us after the + * sure that device ref_clk is active for specific time after * hibern8 enter. */ - if (!enable) - udelay(1); + if (!enable) { + unsigned long gating_wait; + + gating_wait = host->hba->dev_info.clk_gating_wait_us; + if (!gating_wait) { + udelay(1); + } else { + /* + * bRefClkGatingWaitTime defines the minimum + * time for which the reference clock is + * required by device during transition from + * HS-MODE to LS-MODE or HIBERN8 state. Give it + * more delay to be on the safe side. + */ + gating_wait += 10; + usleep_range(gating_wait, gating_wait + 10); + } + } writel_relaxed(temp, host->dev_ref_clk_ctrl_mmio);