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* [PATCH V1] mmc: sdhci-msm: Don't enable PWRSAVE_DLL for certain sdhc hosts
@ 2020-02-07  8:01 Veerabhadrarao Badiganti
  2020-02-07 12:04 ` [PATCH V2] " Veerabhadrarao Badiganti
  0 siblings, 1 reply; 3+ messages in thread
From: Veerabhadrarao Badiganti @ 2020-02-07  8:01 UTC (permalink / raw)
  To: ulf.hansson, adrian.hunter
  Cc: asutoshd, stummala, sayalil, cang, rampraka, linux-mmc,
	linux-kernel, linux-arm-msm, Ritesh Harjani,
	Veerabhadrarao Badiganti, Andy Gross, Bjorn Andersson

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

^ permalink raw reply	[flat|nested] 3+ messages in thread

* [PATCH V2] mmc: sdhci-msm: Don't enable PWRSAVE_DLL for certain sdhc hosts
  2020-02-07  8:01 [PATCH V1] mmc: sdhci-msm: Don't enable PWRSAVE_DLL for certain sdhc hosts Veerabhadrarao Badiganti
@ 2020-02-07 12:04 ` " Veerabhadrarao Badiganti
  2020-02-07 12:07   ` Can Guo
  0 siblings, 1 reply; 3+ messages in thread
From: Veerabhadrarao Badiganti @ 2020-02-07 12:04 UTC (permalink / raw)
  To: ulf.hansson, adrian.hunter
  Cc: asutoshd, stummala, sayalil, cang, rampraka, linux-mmc,
	linux-kernel, linux-arm-msm, Ritesh Harjani,
	Veerabhadrarao Badiganti, Andy Gross, Bjorn Andersson

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>
--

Changes since V1:
  Condition was not correct in V1, which is corrected in V2

--
---
 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..aa5b610 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

^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: [PATCH V2] mmc: sdhci-msm: Don't enable PWRSAVE_DLL for certain sdhc hosts
  2020-02-07 12:04 ` [PATCH V2] " Veerabhadrarao Badiganti
@ 2020-02-07 12:07   ` Can Guo
  0 siblings, 0 replies; 3+ messages in thread
From: Can Guo @ 2020-02-07 12:07 UTC (permalink / raw)
  To: Veerabhadrarao Badiganti
  Cc: ulf.hansson, adrian.hunter, asutoshd, stummala, sayalil,
	rampraka, linux-mmc, linux-kernel, linux-arm-msm, Ritesh Harjani,
	Andy Gross, Bjorn Andersson

On 2020-02-07 20:04, Veerabhadrarao Badiganti wrote:
> 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>
> --

Reviewed-by: Can Guo <cang@codeaurora.org>

> 
> Changes since V1:
>   Condition was not correct in V1, which is corrected in V2
> 
> --
> ---
>  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..aa5b610 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

^ permalink raw reply	[flat|nested] 3+ messages in thread

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Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-02-07  8:01 [PATCH V1] mmc: sdhci-msm: Don't enable PWRSAVE_DLL for certain sdhc hosts Veerabhadrarao Badiganti
2020-02-07 12:04 ` [PATCH V2] " Veerabhadrarao Badiganti
2020-02-07 12:07   ` Can Guo

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