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Message-ID: <537a8695bcadd7d5686a6b6e3c04f2af@codeaurora.org>
Date: Wed, 05 Feb 2020 15:20:10 +0800
From: hongwus@...eaurora.org
To: Can Guo <cang@...eaurora.org>
Cc: asutoshd@...eaurora.org, nguyenb@...eaurora.org,
rnayak@...eaurora.org, linux-scsi@...r.kernel.org,
kernel-team@...roid.com, saravanak@...gle.com, salyzyn@...gle.com,
Andy Gross <agross@...nel.org>,
Bjorn Andersson <bjorn.andersson@...aro.org>,
Alim Akhtar <alim.akhtar@...sung.com>,
Avri Altman <avri.altman@....com>,
"James E.J. Bottomley" <jejb@...ux.ibm.com>,
"Martin K. Petersen" <martin.petersen@...cle.com>,
linux-arm-msm@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v5 7/8] scsi: ufs-qcom: Delay specific time before gate
ref clk
On 2020-02-03 17:17, Can Guo wrote:
> 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.
>
> Signed-off-by: Can Guo <cang@...eaurora.org>
> Reviewed-by: Asutosh Das <asutoshd@...eaurora.org>
> ---
> drivers/scsi/ufs/ufs-qcom.c | 13 ++++++++++---
> 1 file changed, 10 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/scsi/ufs/ufs-qcom.c b/drivers/scsi/ufs/ufs-qcom.c
> index 85d7c17..3b5b2d9 100644
> --- a/drivers/scsi/ufs/ufs-qcom.c
> +++ b/drivers/scsi/ufs/ufs-qcom.c
> @@ -833,6 +833,8 @@ static int ufs_qcom_bus_register(struct
> ufs_qcom_host *host)
>
> static void ufs_qcom_dev_ref_clk_ctrl(struct ufs_qcom_host *host, bool
> enable)
> {
> + unsigned long gating_wait;
> +
> if (host->dev_ref_clk_ctrl_mmio &&
> (enable ^ host->is_dev_ref_clk_enabled)) {
> u32 temp = readl_relaxed(host->dev_ref_clk_ctrl_mmio);
> @@ -845,11 +847,16 @@ 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) {
> + gating_wait = host->hba->dev_info.clk_gating_wait_us;
> + if (!gating_wait)
> + udelay(1);
> + else
> + usleep_range(gating_wait, gating_wait + 10);
> + }
>
> writel_relaxed(temp, host->dev_ref_clk_ctrl_mmio);
Reviewed-by: Hongwu Su <hongwus@...eaurora.org>
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