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Commit 8b2b5c66 authored by Can Guo's avatar Can Guo
Browse files

FROMGIT: 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: default avatarAsutosh Das <asutoshd@codeaurora.org>
Reviewed-by: default avatarHongwu Su <hongwus@codeaurora.org>
Signed-off-by: default avatarCan Guo <cang@codeaurora.org>
Signed-off-by: default avatarMartin K. Petersen <martin.petersen@oracle.com>

Bug: 150892981
Change-Id: I44b3cbe583741fcfadbb9952fad1037e08175555
(cherry picked from commit 1cbadd0c331fb151fafc698bf2ecc35122953715
https://git.kernel.org/pub/scm/linux/kernel/git/mkp/scsi.git

 5.7/scsi-queue)
Signed-off-by: default avatarCan Guo <cang@codeaurora.org>
parent 0f7ba9fc

drivers/scsi/ufs/ufs-qcom.c

+19 −3
Original line number Diff line number Diff line
@@ -801,11 +801,27 @@ 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)

		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);