From: Veerabhadrarao Badiganti <vbadigan@codeaurora.org>
To: ulf.hansson@linaro.org, adrian.hunter@intel.com
Cc: asutoshd@codeaurora.org, stummala@codeaurora.org,
sayalil@codeaurora.org, cang@codeaurora.org,
rampraka@codeaurora.org, linux-mmc@vger.kernel.org,
linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org,
Ritesh Harjani <riteshh@codeaurora.org>,
Veerabhadrarao Badiganti <vbadigan@codeaurora.org>,
Andy Gross <agross@kernel.org>,
Bjorn Andersson <bjorn.andersson@linaro.org>
Subject: [PATCH V1] mmc: sdhci-msm: Don't enable PWRSAVE_DLL for certain sdhc hosts
Date: Fri, 7 Feb 2020 13:31:56 +0530 [thread overview]
Message-ID: <1581062518-11655-1-git-send-email-vbadigan@codeaurora.org> (raw)
From: Ritesh Harjani <riteshh@codeaurora.org>
SDHC core with new 14lpp and later tech DLL should not enable
PWRSAVE_DLL since such controller's internal gating cannot meet
following MCLK requirement:
When MCLK is gated OFF, it is not gated for less than 0.5us and MCLK
must be switched on for at-least 1us before DATA starts coming.
Adding support for this requirement.
Signed-off-by: Ritesh Harjani <riteshh@codeaurora.org>
Signed-off-by: Veerabhadrarao Badiganti <vbadigan@codeaurora.org>
---
drivers/mmc/host/sdhci-msm.c | 18 +++++++++++++++---
1 file changed, 15 insertions(+), 3 deletions(-)
diff --git a/drivers/mmc/host/sdhci-msm.c b/drivers/mmc/host/sdhci-msm.c
index c3a160c..f27f891 100644
--- a/drivers/mmc/host/sdhci-msm.c
+++ b/drivers/mmc/host/sdhci-msm.c
@@ -977,9 +977,21 @@ static int sdhci_msm_cm_dll_sdc4_calibration(struct sdhci_host *host)
goto out;
}
- config = readl_relaxed(host->ioaddr + msm_offset->core_vendor_spec3);
- config |= CORE_PWRSAVE_DLL;
- writel_relaxed(config, host->ioaddr + msm_offset->core_vendor_spec3);
+ /*
+ * Set CORE_PWRSAVE_DLL bit in CORE_VENDOR_SPEC3.
+ * When MCLK is gated OFF, it is not gated for less than 0.5us
+ * and MCLK must be switched on for at-least 1us before DATA
+ * starts coming. Controllers with 14lpp and later tech DLL cannot
+ * guarantee above requirement. So PWRSAVE_DLL should not be
+ * turned on for host controllers using this DLL.
+ */
+ if (msm_host->use_14lpp_dll_reset) {
+ config = readl_relaxed(host->ioaddr +
+ msm_offset->core_vendor_spec3);
+ config |= CORE_PWRSAVE_DLL;
+ writel_relaxed(config, host->ioaddr +
+ msm_offset->core_vendor_spec3);
+ }
/*
* Drain writebuffer to ensure above DLL calibration
--
Qualcomm India Private Limited, on behalf of Qualcomm Innovation Center, Inc., is a member of Code Aurora Forum, a Linux Foundation Collaborative Project
next reply other threads:[~2020-02-07 8:02 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-07 8:01 Veerabhadrarao Badiganti [this message]
2020-02-07 12:04 ` [PATCH V2] mmc: sdhci-msm: Don't enable PWRSAVE_DLL for certain sdhc hosts Veerabhadrarao Badiganti
2020-02-07 12:07 ` Can Guo
2020-02-18 7:11 ` Adrian Hunter
2020-02-18 23:38 ` Ulf Hansson
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