[PATCH V2] mmc: sdhci-msm: Reset GCC_SDCC_BCR register for SDHC

[PATCH V2] mmc: sdhci-msm: Reset GCC_SDCC_BCR register for SDHC

[Shaik Sajida Bhanu]

Reset GCC_SDCC_BCR register before every fresh initilazation. This will
reset whole SDHC-msm controller, clears the previous power control
states and avoids, software reset timeout issues as below.

[ 5.458061][ T262] mmc1: Reset 0x1 never completed.
[ 5.462454][ T262] mmc1: sdhci: ============ SDHCI REGISTER DUMP
===========
[ 5.469065][ T262] mmc1: sdhci: Sys addr: 0x00000000 | Version:
0x00007202
[ 5.475688][ T262] mmc1: sdhci: Blk size: 0x00000000 | Blk cnt:
0x00000000
[ 5.482315][ T262] mmc1: sdhci: Argument: 0x00000000 | Trn mode:
0x00000000
[ 5.488927][ T262] mmc1: sdhci: Present: 0x01f800f0 | Host ctl:
0x00000000
[ 5.495539][ T262] mmc1: sdhci: Power: 0x00000000 | Blk gap: 0x00000000
[ 5.502162][ T262] mmc1: sdhci: Wake-up: 0x00000000 | Clock: 0x00000003
[ 5.508768][ T262] mmc1: sdhci: Timeout: 0x00000000 | Int stat:
0x00000000
[ 5.515381][ T262] mmc1: sdhci: Int enab: 0x00000000 | Sig enab:
0x00000000
[ 5.521996][ T262] mmc1: sdhci: ACmd stat: 0x00000000 | Slot int:
0x00000000
[ 5.528607][ T262] mmc1: sdhci: Caps: 0x362dc8b2 | Caps_1: 0x0000808f
[ 5.535227][ T262] mmc1: sdhci: Cmd: 0x00000000 | Max curr: 0x00000000
[ 5.541841][ T262] mmc1: sdhci: Resp[0]: 0x00000000 | Resp[1]:
0x00000000
[ 5.548454][ T262] mmc1: sdhci: Resp[2]: 0x00000000 | Resp[3]:
0x00000000
[ 5.555079][ T262] mmc1: sdhci: Host ctl2: 0x00000000
[ 5.559651][ T262] mmc1: sdhci_msm: ----------- VENDOR REGISTER
DUMP-----------
[ 5.566621][ T262] mmc1: sdhci_msm: DLL sts: 0x00000000 | DLL cfg:
0x6000642c |
DLL cfg2: 0x0020a000
[ 5.575465][ T262] mmc1: sdhci_msm: DLL cfg3: 0x00000000 | DLL usr ctl:
0x00010800 | DDR cfg: 0x80040873
[ 5.584658][ T262] mmc1: sdhci_msm: Vndr func: 0x00018a9c | Vndr func2 :
0xf88218a8 Vndr func3: 0x02626040

Fixes: 0eb0d9f4de34 ("mmc: sdhci-msm: Initial support for Qualcomm
chipsets")

Signed-off-by: Shaik Sajida Bhanu <quic_c_sbhanu@quicinc.com>
---

Changes since V1:
	- Added fixes tag as suggested by Ulf Hansson.
	- Replaced devm_reset_control_get() with
	  devm_reset_control_get_optional_exclusive() as suggested by
	  Ulf Hansson.
---
 drivers/mmc/host/sdhci-msm.c | 48 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 48 insertions(+)

diff --git a/drivers/mmc/host/sdhci-msm.c b/drivers/mmc/host/sdhci-msm.c
index 50c71e0..cb33c9a 100644
--- a/drivers/mmc/host/sdhci-msm.c
+++ b/drivers/mmc/host/sdhci-msm.c
@@ -17,6 +17,7 @@
 #include <linux/regulator/consumer.h>
 #include <linux/interconnect.h>
 #include <linux/pinctrl/consumer.h>
+#include <linux/reset.h>
 
 #include "sdhci-pltfm.h"
 #include "cqhci.h"
@@ -284,6 +285,7 @@ struct sdhci_msm_host {
 	bool uses_tassadar_dll;
 	u32 dll_config;
 	u32 ddr_config;
+	struct reset_control *core_reset;
 	bool vqmmc_enabled;
 };
 
@@ -2482,6 +2484,45 @@ static inline void sdhci_msm_get_of_property(struct platform_device *pdev,
 	of_property_read_u32(node, "qcom,dll-config", &msm_host->dll_config);
 }
 
+static int sdhci_msm_gcc_reset(struct platform_device *pdev,
+	       struct sdhci_host *host)
+{
+	struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
+	struct sdhci_msm_host *msm_host = sdhci_pltfm_priv(pltfm_host);
+	int ret = 0;
+
+	msm_host->core_reset = devm_reset_control_get_optional_exclusive(&pdev->dev, "core_reset");
+	if (IS_ERR(msm_host->core_reset)) {
+		ret = PTR_ERR(msm_host->core_reset);
+		dev_err(&pdev->dev, "core_reset unavailable (%d)\n", ret);
+		msm_host->core_reset = NULL;
+	}
+	if (msm_host->core_reset) {
+		ret = reset_control_assert(msm_host->core_reset);
+		if (ret) {
+			dev_err(&pdev->dev, "core_reset assert failed (%d)\n",
+						ret);
+			goto out;
+		}
+		/*
+		 * The hardware requirement for delay between assert/deassert
+		 * is at least 3-4 sleep clock (32.7KHz) cycles, which comes to
+		 * ~125us (4/32768). To be on the safe side add 200us delay.
+		 */
+		usleep_range(200, 210);
+
+		ret = reset_control_deassert(msm_host->core_reset);
+		if (ret) {
+			dev_err(&pdev->dev, "core_reset deassert failed (%d)\n",
+						ret);
+			goto out;
+		}
+		usleep_range(200, 210);
+	}
+
+out:
+	return ret;
+}
 
 static int sdhci_msm_probe(struct platform_device *pdev)
 {
@@ -2529,6 +2570,13 @@ static int sdhci_msm_probe(struct platform_device *pdev)
 
 	msm_host->saved_tuning_phase = INVALID_TUNING_PHASE;
 
+	ret = sdhci_msm_gcc_reset(pdev, host);
+	if (ret) {
+		dev_err(&pdev->dev, "core_reset assert/deassert failed (%d)\n",
+					ret);
+		goto pltfm_free;
+	}
+
 	/* Setup SDCC bus voter clock. */
 	msm_host->bus_clk = devm_clk_get(&pdev->dev, "bus");
 	if (!IS_ERR(msm_host->bus_clk)) {
-- 
QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member 
of Code Aurora Forum, hosted by The Linux Foundation

Re: [PATCH V2] mmc: sdhci-msm: Reset GCC_SDCC_BCR register for SDHC

[Bjorn Andersson]

On Thu 10 Mar 07:40 PST 2022, Shaik Sajida Bhanu wrote:

> Reset GCC_SDCC_BCR register before every fresh initilazation. This will
> reset whole SDHC-msm controller, clears the previous power control
> states and avoids, software reset timeout issues as below.
> 

Nice, we've gotten reports about this from time to time.

> [ 5.458061][ T262] mmc1: Reset 0x1 never completed.
> [ 5.462454][ T262] mmc1: sdhci: ============ SDHCI REGISTER DUMP
> ===========
> [ 5.469065][ T262] mmc1: sdhci: Sys addr: 0x00000000 | Version:
> 0x00007202
> [ 5.475688][ T262] mmc1: sdhci: Blk size: 0x00000000 | Blk cnt:
> 0x00000000
> [ 5.482315][ T262] mmc1: sdhci: Argument: 0x00000000 | Trn mode:
> 0x00000000
> [ 5.488927][ T262] mmc1: sdhci: Present: 0x01f800f0 | Host ctl:
> 0x00000000
> [ 5.495539][ T262] mmc1: sdhci: Power: 0x00000000 | Blk gap: 0x00000000
> [ 5.502162][ T262] mmc1: sdhci: Wake-up: 0x00000000 | Clock: 0x00000003
> [ 5.508768][ T262] mmc1: sdhci: Timeout: 0x00000000 | Int stat:
> 0x00000000
> [ 5.515381][ T262] mmc1: sdhci: Int enab: 0x00000000 | Sig enab:
> 0x00000000
> [ 5.521996][ T262] mmc1: sdhci: ACmd stat: 0x00000000 | Slot int:
> 0x00000000
> [ 5.528607][ T262] mmc1: sdhci: Caps: 0x362dc8b2 | Caps_1: 0x0000808f
> [ 5.535227][ T262] mmc1: sdhci: Cmd: 0x00000000 | Max curr: 0x00000000
> [ 5.541841][ T262] mmc1: sdhci: Resp[0]: 0x00000000 | Resp[1]:
> 0x00000000
> [ 5.548454][ T262] mmc1: sdhci: Resp[2]: 0x00000000 | Resp[3]:
> 0x00000000
> [ 5.555079][ T262] mmc1: sdhci: Host ctl2: 0x00000000
> [ 5.559651][ T262] mmc1: sdhci_msm: ----------- VENDOR REGISTER
> DUMP-----------
> [ 5.566621][ T262] mmc1: sdhci_msm: DLL sts: 0x00000000 | DLL cfg:
> 0x6000642c |
> DLL cfg2: 0x0020a000
> [ 5.575465][ T262] mmc1: sdhci_msm: DLL cfg3: 0x00000000 | DLL usr ctl:
> 0x00010800 | DDR cfg: 0x80040873
> [ 5.584658][ T262] mmc1: sdhci_msm: Vndr func: 0x00018a9c | Vndr func2 :
> 0xf88218a8 Vndr func3: 0x02626040

Please ignore the line length "limit" and leave these unwrapped.

> 
> Fixes: 0eb0d9f4de34 ("mmc: sdhci-msm: Initial support for Qualcomm
> chipsets")

This as well, and please drop the empty line between Fixes: and
Signed-off-by:.

> 
> Signed-off-by: Shaik Sajida Bhanu <quic_c_sbhanu@quicinc.com>
> ---
> 
> Changes since V1:
> 	- Added fixes tag as suggested by Ulf Hansson.
> 	- Replaced devm_reset_control_get() with
> 	  devm_reset_control_get_optional_exclusive() as suggested by
> 	  Ulf Hansson.
> ---
>  drivers/mmc/host/sdhci-msm.c | 48 ++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 48 insertions(+)
> 
> diff --git a/drivers/mmc/host/sdhci-msm.c b/drivers/mmc/host/sdhci-msm.c
> index 50c71e0..cb33c9a 100644
> --- a/drivers/mmc/host/sdhci-msm.c
> +++ b/drivers/mmc/host/sdhci-msm.c
> @@ -17,6 +17,7 @@
>  #include <linux/regulator/consumer.h>
>  #include <linux/interconnect.h>
>  #include <linux/pinctrl/consumer.h>
> +#include <linux/reset.h>
>  
>  #include "sdhci-pltfm.h"
>  #include "cqhci.h"
> @@ -284,6 +285,7 @@ struct sdhci_msm_host {
>  	bool uses_tassadar_dll;
>  	u32 dll_config;
>  	u32 ddr_config;
> +	struct reset_control *core_reset;

As you only reset the controller once, during probe, this can be a local
variable in sdhci_msm_gcc_reset().

>  	bool vqmmc_enabled;
>  };
>  
> @@ -2482,6 +2484,45 @@ static inline void sdhci_msm_get_of_property(struct platform_device *pdev,
>  	of_property_read_u32(node, "qcom,dll-config", &msm_host->dll_config);
>  }
>  
> +static int sdhci_msm_gcc_reset(struct platform_device *pdev,

You don't need pdev here, take a struct deivce * in and pass &pdev->dev.

> +	       struct sdhci_host *host)
> +{
> +	struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
> +	struct sdhci_msm_host *msm_host = sdhci_pltfm_priv(pltfm_host);
> +	int ret = 0;
> +
> +	msm_host->core_reset = devm_reset_control_get_optional_exclusive(&pdev->dev, "core_reset");

No need to hold onto that, so use the non-devm variant and free the
reset at the end of the function.

> +	if (IS_ERR(msm_host->core_reset)) {
> +		ret = PTR_ERR(msm_host->core_reset);
> +		dev_err(&pdev->dev, "core_reset unavailable (%d)\n", ret);
> +		msm_host->core_reset = NULL;

return dev_err_probe(&pdev->dev, PTR_ERR(msm_host->core_reset), "unable to acquire core_reset\n");

> +	}
> +	if (msm_host->core_reset) {

If you flip this around as:

	if (!msm_host->core_reset)
		return 0;

You don't need to zero-initialize ret, use goto and indent
this block.

> +		ret = reset_control_assert(msm_host->core_reset);
> +		if (ret) {
> +			dev_err(&pdev->dev, "core_reset assert failed (%d)\n",
> +						ret);
> +			goto out;

return dev_err_probe();

> +		}
> +		/*
> +		 * The hardware requirement for delay between assert/deassert
> +		 * is at least 3-4 sleep clock (32.7KHz) cycles, which comes to
> +		 * ~125us (4/32768). To be on the safe side add 200us delay.
> +		 */
> +		usleep_range(200, 210);
> +
> +		ret = reset_control_deassert(msm_host->core_reset);
> +		if (ret) {
> +			dev_err(&pdev->dev, "core_reset deassert failed (%d)\n",
> +						ret);
> +			goto out;

return dev_err_probe()

> +		}
> +		usleep_range(200, 210);

The comment above says that we need to hold reset for 125us, is this
delay in here in error or should the comment above mention that this
needs to be done after deasserting the reset as well?

> +	}
> +
> +out:
> +	return ret;

With above, you can return 0 here.

> +}
>  
>  static int sdhci_msm_probe(struct platform_device *pdev)
>  {
> @@ -2529,6 +2570,13 @@ static int sdhci_msm_probe(struct platform_device *pdev)
>  
>  	msm_host->saved_tuning_phase = INVALID_TUNING_PHASE;
>  
> +	ret = sdhci_msm_gcc_reset(pdev, host);
> +	if (ret) {
> +		dev_err(&pdev->dev, "core_reset assert/deassert failed (%d)\n",
> +					ret);

You just printed in sdhci_msm_gcc_reset(), no need to print again.

Regards,
Bjorn

> +		goto pltfm_free;
> +	}
> +
>  	/* Setup SDCC bus voter clock. */
>  	msm_host->bus_clk = devm_clk_get(&pdev->dev, "bus");
>  	if (!IS_ERR(msm_host->bus_clk)) {
> -- 
> QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member 
> of Code Aurora Forum, hosted by The Linux Foundation
> 

RE: [PATCH V2] mmc: sdhci-msm: Reset GCC_SDCC_BCR register for SDHC

[Sajida Bhanu (Temp) (QUIC)]

Hi,

Thanks for the review.

Please find the inline comments.

Thanks,
Sajida
> -----Original Message-----
> From: Bjorn Andersson <bjorn.andersson@linaro.org>
> Sent: Friday, March 11, 2022 5:10 AM
> To: Sajida Bhanu (Temp) (QUIC) <quic_c_sbhanu@quicinc.com>
> Cc: adrian.hunter@intel.com; agross@kernel.org; ulf.hansson@linaro.org;
> p.zabel@pengutronix.de; chris@printf.net; gdjakov@mm-sol.com; linux-
> mmc@vger.kernel.org; linux-arm-msm@vger.kernel.org; linux-
> kernel@vger.kernel.org; Asutosh Das (QUIC) <quic_asutoshd@quicinc.com>;
> Ram Prakash Gupta (QUIC) <quic_rampraka@quicinc.com>; Pradeep
> Pragallapati (QUIC) <quic_pragalla@quicinc.com>; Sarthak Garg (QUIC)
> <quic_sartgarg@quicinc.com>; Nitin Rawat (QUIC)
> <quic_nitirawa@quicinc.com>; Sayali Lokhande (QUIC)
> <quic_sayalil@quicinc.com>
> Subject: Re: [PATCH V2] mmc: sdhci-msm: Reset GCC_SDCC_BCR register for
> SDHC
> 
> On Thu 10 Mar 07:40 PST 2022, Shaik Sajida Bhanu wrote:
> 
> > Reset GCC_SDCC_BCR register before every fresh initilazation. This
> > will reset whole SDHC-msm controller, clears the previous power
> > control states and avoids, software reset timeout issues as below.
> >
> 
> Nice, we've gotten reports about this from time to time.
> 
> > [ 5.458061][ T262] mmc1: Reset 0x1 never completed.
> > [ 5.462454][ T262] mmc1: sdhci: ============ SDHCI REGISTER DUMP
> > =========== [ 5.469065][ T262] mmc1: sdhci: Sys addr: 0x00000000 |
> > Version:
> > 0x00007202
> > [ 5.475688][ T262] mmc1: sdhci: Blk size: 0x00000000 | Blk cnt:
> > 0x00000000
> > [ 5.482315][ T262] mmc1: sdhci: Argument: 0x00000000 | Trn mode:
> > 0x00000000
> > [ 5.488927][ T262] mmc1: sdhci: Present: 0x01f800f0 | Host ctl:
> > 0x00000000
> > [ 5.495539][ T262] mmc1: sdhci: Power: 0x00000000 | Blk gap:
> > 0x00000000 [ 5.502162][ T262] mmc1: sdhci: Wake-up: 0x00000000 |
> > Clock: 0x00000003 [ 5.508768][ T262] mmc1: sdhci: Timeout: 0x00000000 |
> Int stat:
> > 0x00000000
> > [ 5.515381][ T262] mmc1: sdhci: Int enab: 0x00000000 | Sig enab:
> > 0x00000000
> > [ 5.521996][ T262] mmc1: sdhci: ACmd stat: 0x00000000 | Slot int:
> > 0x00000000
> > [ 5.528607][ T262] mmc1: sdhci: Caps: 0x362dc8b2 | Caps_1: 0x0000808f
> > [ 5.535227][ T262] mmc1: sdhci: Cmd: 0x00000000 | Max curr: 0x00000000
> > [ 5.541841][ T262] mmc1: sdhci: Resp[0]: 0x00000000 | Resp[1]:
> > 0x00000000
> > [ 5.548454][ T262] mmc1: sdhci: Resp[2]: 0x00000000 | Resp[3]:
> > 0x00000000
> > [ 5.555079][ T262] mmc1: sdhci: Host ctl2: 0x00000000 [ 5.559651][
> > T262] mmc1: sdhci_msm: ----------- VENDOR REGISTER
> > DUMP-----------
> > [ 5.566621][ T262] mmc1: sdhci_msm: DLL sts: 0x00000000 | DLL cfg:
> > 0x6000642c |
> > DLL cfg2: 0x0020a000
> > [ 5.575465][ T262] mmc1: sdhci_msm: DLL cfg3: 0x00000000 | DLL usr ctl:
> > 0x00010800 | DDR cfg: 0x80040873
> > [ 5.584658][ T262] mmc1: sdhci_msm: Vndr func: 0x00018a9c | Vndr func2 :
> > 0xf88218a8 Vndr func3: 0x02626040
> 
> Please ignore the line length "limit" and leave these unwrapped.
> 
Sure
> >
> > Fixes: 0eb0d9f4de34 ("mmc: sdhci-msm: Initial support for Qualcomm
> > chipsets")
> 
> This as well, and please drop the empty line between Fixes: and Signed-off-
> by:.
> 
Sure
> >
> > Signed-off-by: Shaik Sajida Bhanu <quic_c_sbhanu@quicinc.com>
> > ---
> >
> > Changes since V1:
> > 	- Added fixes tag as suggested by Ulf Hansson.
> > 	- Replaced devm_reset_control_get() with
> > 	  devm_reset_control_get_optional_exclusive() as suggested by
> > 	  Ulf Hansson.
> > ---
> >  drivers/mmc/host/sdhci-msm.c | 48
> > ++++++++++++++++++++++++++++++++++++++++++++
> >  1 file changed, 48 insertions(+)
> >
> > diff --git a/drivers/mmc/host/sdhci-msm.c
> > b/drivers/mmc/host/sdhci-msm.c index 50c71e0..cb33c9a 100644
> > --- a/drivers/mmc/host/sdhci-msm.c
> > +++ b/drivers/mmc/host/sdhci-msm.c
> > @@ -17,6 +17,7 @@
> >  #include <linux/regulator/consumer.h>  #include
> > <linux/interconnect.h>  #include <linux/pinctrl/consumer.h>
> > +#include <linux/reset.h>
> >
> >  #include "sdhci-pltfm.h"
> >  #include "cqhci.h"
> > @@ -284,6 +285,7 @@ struct sdhci_msm_host {
> >  	bool uses_tassadar_dll;
> >  	u32 dll_config;
> >  	u32 ddr_config;
> > +	struct reset_control *core_reset;
> 
> As you only reset the controller once, during probe, this can be a local
> variable in sdhci_msm_gcc_reset().
Hi,

In future if any requirement to reset gcc , for example if we want to reset gcc as a part of hardware reset then we can use this core_reset right.

Thanks,
Sajida
> 
> >  	bool vqmmc_enabled;
> >  };
> >
> > @@ -2482,6 +2484,45 @@ static inline void
> sdhci_msm_get_of_property(struct platform_device *pdev,
> >  	of_property_read_u32(node, "qcom,dll-config",
> > &msm_host->dll_config);  }
> >
> > +static int sdhci_msm_gcc_reset(struct platform_device *pdev,
> 
> You don't need pdev here, take a struct deivce * in and pass &pdev->dev.
Ok
> 
> > +	       struct sdhci_host *host)
> > +{
> > +	struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
> > +	struct sdhci_msm_host *msm_host = sdhci_pltfm_priv(pltfm_host);
> > +	int ret = 0;
> > +
> > +	msm_host->core_reset =
> > +devm_reset_control_get_optional_exclusive(&pdev->dev,
> "core_reset");
> 
> No need to hold onto that, so use the non-devm variant and free the reset at
> the end of the function.
Sorry didn't get this. 
Can you please point me any reference for this.
> 
> > +	if (IS_ERR(msm_host->core_reset)) {
> > +		ret = PTR_ERR(msm_host->core_reset);
> > +		dev_err(&pdev->dev, "core_reset unavailable (%d)\n", ret);
> > +		msm_host->core_reset = NULL;
> 
> return dev_err_probe(&pdev->dev, PTR_ERR(msm_host->core_reset),
> "unable to acquire core_reset\n");
> 
> > +	}
> > +	if (msm_host->core_reset) {
> 
> If you flip this around as:
> 
> 	if (!msm_host->core_reset)
> 		return 0;
> 
> You don't need to zero-initialize ret, use goto and indent this block.
Sure
> 
> > +		ret = reset_control_assert(msm_host->core_reset);
> > +		if (ret) {
> > +			dev_err(&pdev->dev, "core_reset assert failed
> (%d)\n",
> > +						ret);
> > +			goto out;
> 
> return dev_err_probe();
> 
Sure
> > +		}
> > +		/*
> > +		 * The hardware requirement for delay between
> assert/deassert
> > +		 * is at least 3-4 sleep clock (32.7KHz) cycles, which comes to
> > +		 * ~125us (4/32768). To be on the safe side add 200us delay.
> > +		 */
> > +		usleep_range(200, 210);
> > +
> > +		ret = reset_control_deassert(msm_host->core_reset);
> > +		if (ret) {
> > +			dev_err(&pdev->dev, "core_reset deassert failed
> (%d)\n",
> > +						ret);
> > +			goto out;
> 
> return dev_err_probe()
Sure
> 
> > +		}
> > +		usleep_range(200, 210);
> 
> The comment above says that we need to hold reset for 125us, is this delay
> in here in error or should the comment above mention that this needs to be
> done after deasserting the reset as well?
Yes we need delay after deasserting the reset as well.
> 
> > +	}
> > +
> > +out:
> > +	return ret;
> 
> With above, you can return 0 here.
> 
> > +}
> >
> >  static int sdhci_msm_probe(struct platform_device *pdev)  { @@
> > -2529,6 +2570,13 @@ static int sdhci_msm_probe(struct platform_device
> > *pdev)
> >
> >  	msm_host->saved_tuning_phase = INVALID_TUNING_PHASE;
> >
> > +	ret = sdhci_msm_gcc_reset(pdev, host);
> > +	if (ret) {
> > +		dev_err(&pdev->dev, "core_reset assert/deassert failed
> (%d)\n",
> > +					ret);
> 
> You just printed in sdhci_msm_gcc_reset(), no need to print again.
> 
> Regards,
> Bjorn
> 
Okay Sure
> > +		goto pltfm_free;
> > +	}
> > +
> >  	/* Setup SDCC bus voter clock. */
> >  	msm_host->bus_clk = devm_clk_get(&pdev->dev, "bus");
> >  	if (!IS_ERR(msm_host->bus_clk)) {
> > --
> > QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a
> > member of Code Aurora Forum, hosted by The Linux Foundation
> >

Re: [PATCH V2] mmc: sdhci-msm: Reset GCC_SDCC_BCR register for SDHC

[Sajida Bhanu (Temp)]

On 3/15/2022 2:47 PM, Sajida Bhanu (Temp) (QUIC) wrote:
> Hi,
>
> Thanks for the review.
>
> Please find the inline comments.
>
> Thanks,
> Sajida
>> -----Original Message-----
>> From: Bjorn Andersson <bjorn.andersson@linaro.org>
>> Sent: Friday, March 11, 2022 5:10 AM
>> To: Sajida Bhanu (Temp) (QUIC) <quic_c_sbhanu@quicinc.com>
>> Cc: adrian.hunter@intel.com; agross@kernel.org; ulf.hansson@linaro.org;
>> p.zabel@pengutronix.de; chris@printf.net; gdjakov@mm-sol.com; linux-
>> mmc@vger.kernel.org; linux-arm-msm@vger.kernel.org; linux-
>> kernel@vger.kernel.org; Asutosh Das (QUIC) <quic_asutoshd@quicinc.com>;
>> Ram Prakash Gupta (QUIC) <quic_rampraka@quicinc.com>; Pradeep
>> Pragallapati (QUIC) <quic_pragalla@quicinc.com>; Sarthak Garg (QUIC)
>> <quic_sartgarg@quicinc.com>; Nitin Rawat (QUIC)
>> <quic_nitirawa@quicinc.com>; Sayali Lokhande (QUIC)
>> <quic_sayalil@quicinc.com>
>> Subject: Re: [PATCH V2] mmc: sdhci-msm: Reset GCC_SDCC_BCR register for
>> SDHC
>>
>> On Thu 10 Mar 07:40 PST 2022, Shaik Sajida Bhanu wrote:
>>
>>> Reset GCC_SDCC_BCR register before every fresh initilazation. This
>>> will reset whole SDHC-msm controller, clears the previous power
>>> control states and avoids, software reset timeout issues as below.
>>>
>> Nice, we've gotten reports about this from time to time.
>>
>>> [ 5.458061][ T262] mmc1: Reset 0x1 never completed.
>>> [ 5.462454][ T262] mmc1: sdhci: ============ SDHCI REGISTER DUMP
>>> =========== [ 5.469065][ T262] mmc1: sdhci: Sys addr: 0x00000000 |
>>> Version:
>>> 0x00007202
>>> [ 5.475688][ T262] mmc1: sdhci: Blk size: 0x00000000 | Blk cnt:
>>> 0x00000000
>>> [ 5.482315][ T262] mmc1: sdhci: Argument: 0x00000000 | Trn mode:
>>> 0x00000000
>>> [ 5.488927][ T262] mmc1: sdhci: Present: 0x01f800f0 | Host ctl:
>>> 0x00000000
>>> [ 5.495539][ T262] mmc1: sdhci: Power: 0x00000000 | Blk gap:
>>> 0x00000000 [ 5.502162][ T262] mmc1: sdhci: Wake-up: 0x00000000 |
>>> Clock: 0x00000003 [ 5.508768][ T262] mmc1: sdhci: Timeout: 0x00000000 |
>> Int stat:
>>> 0x00000000
>>> [ 5.515381][ T262] mmc1: sdhci: Int enab: 0x00000000 | Sig enab:
>>> 0x00000000
>>> [ 5.521996][ T262] mmc1: sdhci: ACmd stat: 0x00000000 | Slot int:
>>> 0x00000000
>>> [ 5.528607][ T262] mmc1: sdhci: Caps: 0x362dc8b2 | Caps_1: 0x0000808f
>>> [ 5.535227][ T262] mmc1: sdhci: Cmd: 0x00000000 | Max curr: 0x00000000
>>> [ 5.541841][ T262] mmc1: sdhci: Resp[0]: 0x00000000 | Resp[1]:
>>> 0x00000000
>>> [ 5.548454][ T262] mmc1: sdhci: Resp[2]: 0x00000000 | Resp[3]:
>>> 0x00000000
>>> [ 5.555079][ T262] mmc1: sdhci: Host ctl2: 0x00000000 [ 5.559651][
>>> T262] mmc1: sdhci_msm: ----------- VENDOR REGISTER
>>> DUMP-----------
>>> [ 5.566621][ T262] mmc1: sdhci_msm: DLL sts: 0x00000000 | DLL cfg:
>>> 0x6000642c |
>>> DLL cfg2: 0x0020a000
>>> [ 5.575465][ T262] mmc1: sdhci_msm: DLL cfg3: 0x00000000 | DLL usr ctl:
>>> 0x00010800 | DDR cfg: 0x80040873
>>> [ 5.584658][ T262] mmc1: sdhci_msm: Vndr func: 0x00018a9c | Vndr func2 :
>>> 0xf88218a8 Vndr func3: 0x02626040
>> Please ignore the line length "limit" and leave these unwrapped.
>>
> Sure
>>> Fixes: 0eb0d9f4de34 ("mmc: sdhci-msm: Initial support for Qualcomm
>>> chipsets")
>> This as well, and please drop the empty line between Fixes: and Signed-off-
>> by:.
>>
> Sure
>>> Signed-off-by: Shaik Sajida Bhanu <quic_c_sbhanu@quicinc.com>
>>> ---
>>>
>>> Changes since V1:
>>>      - Added fixes tag as suggested by Ulf Hansson.
>>>      - Replaced devm_reset_control_get() with
>>>        devm_reset_control_get_optional_exclusive() as suggested by
>>>        Ulf Hansson.
>>> ---
>>>   drivers/mmc/host/sdhci-msm.c | 48
>>> ++++++++++++++++++++++++++++++++++++++++++++
>>>   1 file changed, 48 insertions(+)
>>>
>>> diff --git a/drivers/mmc/host/sdhci-msm.c
>>> b/drivers/mmc/host/sdhci-msm.c index 50c71e0..cb33c9a 100644
>>> --- a/drivers/mmc/host/sdhci-msm.c
>>> +++ b/drivers/mmc/host/sdhci-msm.c
>>> @@ -17,6 +17,7 @@
>>>   #include <linux/regulator/consumer.h>  #include
>>> <linux/interconnect.h>  #include <linux/pinctrl/consumer.h>
>>> +#include <linux/reset.h>
>>>
>>>   #include "sdhci-pltfm.h"
>>>   #include "cqhci.h"
>>> @@ -284,6 +285,7 @@ struct sdhci_msm_host {
>>>      bool uses_tassadar_dll;
>>>      u32 dll_config;
>>>      u32 ddr_config;
>>> +   struct reset_control *core_reset;
>> As you only reset the controller once, during probe, this can be a local
>> variable in sdhci_msm_gcc_reset().
> Hi,
>
> In future if any requirement to reset gcc , for example if we want to reset gcc as a part of hardware reset then we can use this core_reset right.
>
> Thanks,
> Sajida
>>>      bool vqmmc_enabled;
>>>   };
>>>
>>> @@ -2482,6 +2484,45 @@ static inline void
>> sdhci_msm_get_of_property(struct platform_device *pdev,
>>>      of_property_read_u32(node, "qcom,dll-config",
>>> &msm_host->dll_config);  }
>>>
>>> +static int sdhci_msm_gcc_reset(struct platform_device *pdev,
>> You don't need pdev here, take a struct deivce * in and pass &pdev->dev.
> Ok
>>> +          struct sdhci_host *host)
>>> +{
>>> +   struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
>>> +   struct sdhci_msm_host *msm_host = sdhci_pltfm_priv(pltfm_host);
>>> +   int ret = 0;
>>> +
>>> +   msm_host->core_reset =
>>> +devm_reset_control_get_optional_exclusive(&pdev->dev,
>> "core_reset");
>>
>> No need to hold onto that, so use the non-devm variant and free the reset at
>> the end of the function.
> Sorry didn't get this.
> Can you please point me any reference for this.

Hi,

Can you please help with comment on this.

Thanks,

Sajida

>>> +   if (IS_ERR(msm_host->core_reset)) {
>>> +           ret = PTR_ERR(msm_host->core_reset);
>>> +           dev_err(&pdev->dev, "core_reset unavailable (%d)\n", ret);
>>> +           msm_host->core_reset = NULL;
>> return dev_err_probe(&pdev->dev, PTR_ERR(msm_host->core_reset),
>> "unable to acquire core_reset\n");
>>
>>> +   }
>>> +   if (msm_host->core_reset) {
>> If you flip this around as:
>>
>>        if (!msm_host->core_reset)
>>                return 0;
>>
>> You don't need to zero-initialize ret, use goto and indent this block.
> Sure
>>> +           ret = reset_control_assert(msm_host->core_reset);
>>> +           if (ret) {
>>> +                   dev_err(&pdev->dev, "core_reset assert failed
>> (%d)\n",
>>> +                                           ret);
>>> +                   goto out;
>> return dev_err_probe();
>>
> Sure
>>> +           }
>>> +           /*
>>> +            * The hardware requirement for delay between
>> assert/deassert
>>> +            * is at least 3-4 sleep clock (32.7KHz) cycles, which comes to
>>> +            * ~125us (4/32768). To be on the safe side add 200us delay.
>>> +            */
>>> +           usleep_range(200, 210);
>>> +
>>> +           ret = reset_control_deassert(msm_host->core_reset);
>>> +           if (ret) {
>>> +                   dev_err(&pdev->dev, "core_reset deassert failed
>> (%d)\n",
>>> +                                           ret);
>>> +                   goto out;
>> return dev_err_probe()
> Sure
>>> +           }
>>> +           usleep_range(200, 210);
>> The comment above says that we need to hold reset for 125us, is this delay
>> in here in error or should the comment above mention that this needs to be
>> done after deasserting the reset as well?
> Yes we need delay after deasserting the reset as well.
>>> +   }
>>> +
>>> +out:
>>> +   return ret;
>> With above, you can return 0 here.
>>
>>> +}
>>>
>>>   static int sdhci_msm_probe(struct platform_device *pdev)  { @@
>>> -2529,6 +2570,13 @@ static int sdhci_msm_probe(struct platform_device
>>> *pdev)
>>>
>>>      msm_host->saved_tuning_phase = INVALID_TUNING_PHASE;
>>>
>>> +   ret = sdhci_msm_gcc_reset(pdev, host);
>>> +   if (ret) {
>>> +           dev_err(&pdev->dev, "core_reset assert/deassert failed
>> (%d)\n",
>>> +                                   ret);
>> You just printed in sdhci_msm_gcc_reset(), no need to print again.
>>
>> Regards,
>> Bjorn
>>
> Okay Sure
>>> +           goto pltfm_free;
>>> +   }
>>> +
>>>      /* Setup SDCC bus voter clock. */
>>>      msm_host->bus_clk = devm_clk_get(&pdev->dev, "bus");
>>>      if (!IS_ERR(msm_host->bus_clk)) {
>>> --
>>> QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a
>>> member of Code Aurora Forum, hosted by The Linux Foundation
>>>

Re: [PATCH V2] mmc: sdhci-msm: Reset GCC_SDCC_BCR register for SDHC

[Philipp Zabel]

Hi Sajida,

On Do, 2022-03-10 at 21:10 +0530, Shaik Sajida Bhanu wrote:
[...]
> diff --git a/drivers/mmc/host/sdhci-msm.c b/drivers/mmc/host/sdhci-
> msm.c
> index 50c71e0..cb33c9a 100644
> --- a/drivers/mmc/host/sdhci-msm.c
> +++ b/drivers/mmc/host/sdhci-msm.c
[...]
> @@ -2482,6 +2484,45 @@ static inline void sdhci_msm_get_of_property(struct platform_device *pdev,
>         of_property_read_u32(node, "qcom,dll-config", &msm_host->dll_config);
>  }
>  
> +static int sdhci_msm_gcc_reset(struct platform_device *pdev,
> +              struct sdhci_host *host)
> +{
> +       struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
> +       struct sdhci_msm_host *msm_host = sdhci_pltfm_priv(pltfm_host);
> +       int ret = 0;
> +
> +       msm_host->core_reset = devm_reset_control_get_optional_exclusive(&pdev->dev, "core_reset");

I think the "_reset" part in the name is superfluous and this reset
control should be called "core". Is this documented in the sdhci-msm
device tree binding document?

> +       if (IS_ERR(msm_host->core_reset)) {
> +               ret = PTR_ERR(msm_host->core_reset);
> +               dev_err(&pdev->dev, "core_reset unavailable (%d)\n", ret);
> +               msm_host->core_reset = NULL;

As Bjorn pointed out, this error should be returned.
reset_control_get_optional returns NULL if the optional reset control
is not specified in the device tree, so we only land here if there's a
real error.

[...]
> @@ -2529,6 +2570,13 @@ static int sdhci_msm_probe(struct
> platform_device *pdev)
>  
>         msm_host->saved_tuning_phase = INVALID_TUNING_PHASE;
>  
> +       ret = sdhci_msm_gcc_reset(pdev, host);
> +       if (ret) {
> +               dev_err(&pdev->dev, "core_reset assert/deassert failed (%d)\n",
> +                                       ret);
> +               goto pltfm_free;
> +       }
> +
>         /* Setup SDCC bus voter clock. */
>         msm_host->bus_clk = devm_clk_get(&pdev->dev, "bus");
>         if (!IS_ERR(msm_host->bus_clk)) {

I notice that this driver requests resources such as clocks and resets
and then immediately uses them, one by one. It would be better to
request all resources first, and only then start interacting with the
hardware. This is not an issue that can be fixed in this patch,
although maybe it could be prepared for it by separating the
reset_control_get from the _assert/deassert.

regards
Philipp

RE: [PATCH V2] mmc: sdhci-msm: Reset GCC_SDCC_BCR register for SDHC

[Sajida Bhanu (Temp) (QUIC)]

Hi,

Thanks for the review.

Please find the inline comments.

Thanks,
Sajida
> -----Original Message-----
> From: Philipp Zabel <p.zabel@pengutronix.de>
> Sent: Tuesday, March 15, 2022 3:19 PM
> To: Sajida Bhanu (Temp) (QUIC) <quic_c_sbhanu@quicinc.com>;
> adrian.hunter@intel.com; agross@kernel.org; bjorn.andersson@linaro.org;
> ulf.hansson@linaro.org; chris@printf.net; gdjakov@mm-sol.com
> Cc: linux-mmc@vger.kernel.org; linux-arm-msm@vger.kernel.org; linux-
> kernel@vger.kernel.org; Asutosh Das (QUIC) <quic_asutoshd@quicinc.com>;
> Ram Prakash Gupta (QUIC) <quic_rampraka@quicinc.com>; Pradeep
> Pragallapati (QUIC) <quic_pragalla@quicinc.com>; Sarthak Garg (QUIC)
> <quic_sartgarg@quicinc.com>; Nitin Rawat (QUIC)
> <quic_nitirawa@quicinc.com>; Sayali Lokhande (QUIC)
> <quic_sayalil@quicinc.com>
> Subject: Re: [PATCH V2] mmc: sdhci-msm: Reset GCC_SDCC_BCR register for
> SDHC
> 
> Hi Sajida,
> 
> On Do, 2022-03-10 at 21:10 +0530, Shaik Sajida Bhanu wrote:
> [...]
> > diff --git a/drivers/mmc/host/sdhci-msm.c b/drivers/mmc/host/sdhci-
> > msm.c index 50c71e0..cb33c9a 100644
> > --- a/drivers/mmc/host/sdhci-msm.c
> > +++ b/drivers/mmc/host/sdhci-msm.c
> [...]
> > @@ -2482,6 +2484,45 @@ static inline void
> > sdhci_msm_get_of_property(struct platform_device *pdev,
> >         of_property_read_u32(node, "qcom,dll-config",
> > &msm_host->dll_config);
> >  }
> >
> > +static int sdhci_msm_gcc_reset(struct platform_device *pdev,
> > +              struct sdhci_host *host) {
> > +       struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
> > +       struct sdhci_msm_host *msm_host =
> > +sdhci_pltfm_priv(pltfm_host);
> > +       int ret = 0;
> > +
> > +       msm_host->core_reset =
> > +devm_reset_control_get_optional_exclusive(&pdev->dev,
> "core_reset");
> 
> I think the "_reset" part in the name is superfluous and this reset control
> should be called "core". Is this documented in the sdhci-msm device tree
> binding document?
Followed existing clients...
No its not added in the dt-binbing,  will add dt-binding patch in patch version.
> 
> > +       if (IS_ERR(msm_host->core_reset)) {
> > +               ret = PTR_ERR(msm_host->core_reset);
> > +               dev_err(&pdev->dev, "core_reset unavailable (%d)\n",
> > +ret);
> > +               msm_host->core_reset = NULL;
> 
> As Bjorn pointed out, this error should be returned.
> reset_control_get_optional returns NULL if the optional reset control is not
> specified in the device tree, so we only land here if there's a real error.
> 
Ok
> [...]
> > @@ -2529,6 +2570,13 @@ static int sdhci_msm_probe(struct
> > platform_device *pdev)
> >
> >         msm_host->saved_tuning_phase = INVALID_TUNING_PHASE;
> >
> > +       ret = sdhci_msm_gcc_reset(pdev, host);
> > +       if (ret) {
> > +               dev_err(&pdev->dev, "core_reset assert/deassert failed
> > +(%d)\n",
> > +                                       ret);
> > +               goto pltfm_free;
> > +       }
> > +
> >         /* Setup SDCC bus voter clock. */
> >         msm_host->bus_clk = devm_clk_get(&pdev->dev, "bus");
> >         if (!IS_ERR(msm_host->bus_clk)) {
> 
> I notice that this driver requests resources such as clocks and resets and then
> immediately uses them, one by one. It would be better to request all
> resources first, and only then start interacting with the hardware. This is not
> an issue that can be fixed in this patch, although maybe it could be prepared
> for it by separating the reset_control_get from the _assert/deassert.
>
 Sure, we will discuss this proposal internally and update.
> regards
> Philipp