[PATCH v3] mmc: core: try 1.8v signling in ddr mode if host and device

[PATCH v3] mmc: core: try 1.8v signling in ddr mode if host and device

[Chuanxiao Dong]

Even (e)MMC card can support 3.3v to 1.2v vccq in DDR, but not all
host controller can support this, like some of the SDHCI host
which connect to an eMMC device. Some of these host controller
still needs to use 1.8v vccq for supporting DDR mode.

So the sequence will be:
if (host and device can both support 1.2v IO)
	use 1.2v IO;
else if (host and device can both support 1.8v IO)
	use 1.8v IO;
so if host and device can only support 3.3v IO, this is the last choice.

Signed-off-by: Chuanxiao Dong <chuanxiao.dong@intel.com>
Signed-off-by: Yunpeng Gao <yunpeng.gao@intel.com>
---
Changelog V2:
     - For (e)MMC device switching to DDR mode, try 1.2v singaling first. Then
     try 1.8v. If 1.2v and 1.8v are both not supported, use the default 

Changelog V3:
     - continue to try 1.8v/3.3v vccq if there is IO voltage switching failure

 drivers/mmc/core/mmc.c |   34 +++++++++++++++++++++++++---------
 1 file changed, 25 insertions(+), 9 deletions(-)

diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c
index 793c6f7..8d69671 100644
--- a/drivers/mmc/core/mmc.c
+++ b/drivers/mmc/core/mmc.c
@@ -988,19 +988,35 @@ static int mmc_select_hs_ddr(struct mmc_card *card)
 	 * 1.8V vccq at 3.3V core voltage (vcc) is not required
 	 * in the JEDEC spec for DDR.
 	 *
-	 * Do not force change in vccq since we are obviously
-	 * working and no change to vccq is needed.
+	 * Even (e)MMC card can support 3.3v to 1.2v vccq, but not all
+	 * host controller can support this, like some of the SDHCI
+	 * controller which connect to an eMMC device. Some of these
+	 * host controller still needs to use 1.8v vccq for supporting
+	 * DDR mode.
+	 *
+	 * So the sequence will be:
+	 * if (host and device can both support 1.2v IO)
+	 *	use 1.2v IO;
+	 * else if (host and device can both support 1.8v IO)
+	 * 	use 1.8v IO;
+	 * so if host and device can only support 3.3v IO, this is the
+	 * last choice.
 	 *
 	 * WARNING: eMMC rules are NOT the same as SD DDR
 	 */
-	if (card->mmc_avail_type & EXT_CSD_CARD_TYPE_DDR_1_2V) {
-		err = __mmc_set_signal_voltage(host,
-				MMC_SIGNAL_VOLTAGE_120);
-		if (err)
-			return err;
-	}
+	err = -EINVAL;
+	if (card->mmc_avail_type & EXT_CSD_CARD_TYPE_DDR_1_2V)
+		err = __mmc_set_signal_voltage(host, MMC_SIGNAL_VOLTAGE_120);
 
-	mmc_set_timing(host, MMC_TIMING_MMC_DDR52);
+	if (err && (card->mmc_avail_type & EXT_CSD_CARD_TYPE_DDR_1_8V))
+		err = __mmc_set_signal_voltage(host, MMC_SIGNAL_VOLTAGE_180);
+
+	/* make sure vccq is 3.3v after switching disaster */
+	if (err)
+		err = __mmc_set_signal_voltage(host, MMC_SIGNAL_VOLTAGE_330);
+
+	if (!err)
+		mmc_set_timing(host, MMC_TIMING_MMC_DDR52);
 
 	return err;
 }
-- 
1.7.10.4

Re: [PATCH v3] mmc: core: try 1.8v signling in ddr mode if host and device

[Ulf Hansson]

On 15 August 2014 05:28, Chuanxiao Dong <chuanxiao.dong@intel.com> wrote:
> Even (e)MMC card can support 3.3v to 1.2v vccq in DDR, but not all
> host controller can support this, like some of the SDHCI host
> which connect to an eMMC device. Some of these host controller
> still needs to use 1.8v vccq for supporting DDR mode.
>
> So the sequence will be:
> if (host and device can both support 1.2v IO)
>         use 1.2v IO;
> else if (host and device can both support 1.8v IO)
>         use 1.8v IO;
> so if host and device can only support 3.3v IO, this is the last choice.
>
> Signed-off-by: Chuanxiao Dong <chuanxiao.dong@intel.com>
> Signed-off-by: Yunpeng Gao <yunpeng.gao@intel.com>

This looks good to me! But before I queue it for 3.18 I would
appreciate if we could get some help in testing this for some various
platforms, that support MMC DDR.

Kind regards
Uffe

> ---
> Changelog V2:
>      - For (e)MMC device switching to DDR mode, try 1.2v singaling first. Then
>      try 1.8v. If 1.2v and 1.8v are both not supported, use the default
>
> Changelog V3:
>      - continue to try 1.8v/3.3v vccq if there is IO voltage switching failure
>
>  drivers/mmc/core/mmc.c |   34 +++++++++++++++++++++++++---------
>  1 file changed, 25 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c
> index 793c6f7..8d69671 100644
> --- a/drivers/mmc/core/mmc.c
> +++ b/drivers/mmc/core/mmc.c
> @@ -988,19 +988,35 @@ static int mmc_select_hs_ddr(struct mmc_card *card)
>          * 1.8V vccq at 3.3V core voltage (vcc) is not required
>          * in the JEDEC spec for DDR.
>          *
> -        * Do not force change in vccq since we are obviously
> -        * working and no change to vccq is needed.
> +        * Even (e)MMC card can support 3.3v to 1.2v vccq, but not all
> +        * host controller can support this, like some of the SDHCI
> +        * controller which connect to an eMMC device. Some of these
> +        * host controller still needs to use 1.8v vccq for supporting
> +        * DDR mode.
> +        *
> +        * So the sequence will be:
> +        * if (host and device can both support 1.2v IO)
> +        *      use 1.2v IO;
> +        * else if (host and device can both support 1.8v IO)
> +        *      use 1.8v IO;
> +        * so if host and device can only support 3.3v IO, this is the
> +        * last choice.
>          *
>          * WARNING: eMMC rules are NOT the same as SD DDR
>          */
> -       if (card->mmc_avail_type & EXT_CSD_CARD_TYPE_DDR_1_2V) {
> -               err = __mmc_set_signal_voltage(host,
> -                               MMC_SIGNAL_VOLTAGE_120);
> -               if (err)
> -                       return err;
> -       }
> +       err = -EINVAL;
> +       if (card->mmc_avail_type & EXT_CSD_CARD_TYPE_DDR_1_2V)
> +               err = __mmc_set_signal_voltage(host, MMC_SIGNAL_VOLTAGE_120);
>
> -       mmc_set_timing(host, MMC_TIMING_MMC_DDR52);
> +       if (err && (card->mmc_avail_type & EXT_CSD_CARD_TYPE_DDR_1_8V))
> +               err = __mmc_set_signal_voltage(host, MMC_SIGNAL_VOLTAGE_180);
> +
> +       /* make sure vccq is 3.3v after switching disaster */
> +       if (err)
> +               err = __mmc_set_signal_voltage(host, MMC_SIGNAL_VOLTAGE_330);
> +
> +       if (!err)
> +               mmc_set_timing(host, MMC_TIMING_MMC_DDR52);
>
>         return err;
>  }
> --
> 1.7.10.4
>

RE: [PATCH v3] mmc: core: try 1.8v signling in ddr mode if host and device

[Dong, Chuanxiao]

> -----Original Message-----
> From: Ulf Hansson [mailto:ulf.hansson@linaro.org]
> Sent: Friday, August 15, 2014 4:34 PM
> To: Dong, Chuanxiao
> Cc: linux-mmc; chris@printf.org
> Subject: Re: [PATCH v3] mmc: core: try 1.8v signling in ddr mode if host and
> device
> 
> On 15 August 2014 05:28, Chuanxiao Dong <chuanxiao.dong@intel.com>
> wrote:
> > Even (e)MMC card can support 3.3v to 1.2v vccq in DDR, but not all
> > host controller can support this, like some of the SDHCI host which
> > connect to an eMMC device. Some of these host controller still needs
> > to use 1.8v vccq for supporting DDR mode.
> >
> > So the sequence will be:
> > if (host and device can both support 1.2v IO)
> >         use 1.2v IO;
> > else if (host and device can both support 1.8v IO)
> >         use 1.8v IO;
> > so if host and device can only support 3.3v IO, this is the last choice.
> >
> > Signed-off-by: Chuanxiao Dong <chuanxiao.dong@intel.com>
> > Signed-off-by: Yunpeng Gao <yunpeng.gao@intel.com>
> 
> This looks good to me! But before I queue it for 3.18 I would appreciate if we
> could get some help in testing this for some various platforms, that support
> MMC DDR.

Thanks a lot. BTW, this patch is already tested on Intel's platform which can support MMC DDR.

Thanks
Chuanxiao
> 
> Kind regards
> Uffe
> 
> > ---
> > Changelog V2:
> >      - For (e)MMC device switching to DDR mode, try 1.2v singaling first.
> Then
> >      try 1.8v. If 1.2v and 1.8v are both not supported, use the
> > default
> >
> > Changelog V3:
> >      - continue to try 1.8v/3.3v vccq if there is IO voltage switching
> > failure
> >
> >  drivers/mmc/core/mmc.c |   34 +++++++++++++++++++++++++---------
> >  1 file changed, 25 insertions(+), 9 deletions(-)
> >
> > diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c index
> > 793c6f7..8d69671 100644
> > --- a/drivers/mmc/core/mmc.c
> > +++ b/drivers/mmc/core/mmc.c
> > @@ -988,19 +988,35 @@ static int mmc_select_hs_ddr(struct mmc_card
> *card)
> >          * 1.8V vccq at 3.3V core voltage (vcc) is not required
> >          * in the JEDEC spec for DDR.
> >          *
> > -        * Do not force change in vccq since we are obviously
> > -        * working and no change to vccq is needed.
> > +        * Even (e)MMC card can support 3.3v to 1.2v vccq, but not all
> > +        * host controller can support this, like some of the SDHCI
> > +        * controller which connect to an eMMC device. Some of these
> > +        * host controller still needs to use 1.8v vccq for supporting
> > +        * DDR mode.
> > +        *
> > +        * So the sequence will be:
> > +        * if (host and device can both support 1.2v IO)
> > +        *      use 1.2v IO;
> > +        * else if (host and device can both support 1.8v IO)
> > +        *      use 1.8v IO;
> > +        * so if host and device can only support 3.3v IO, this is the
> > +        * last choice.
> >          *
> >          * WARNING: eMMC rules are NOT the same as SD DDR
> >          */
> > -       if (card->mmc_avail_type & EXT_CSD_CARD_TYPE_DDR_1_2V) {
> > -               err = __mmc_set_signal_voltage(host,
> > -                               MMC_SIGNAL_VOLTAGE_120);
> > -               if (err)
> > -                       return err;
> > -       }
> > +       err = -EINVAL;
> > +       if (card->mmc_avail_type & EXT_CSD_CARD_TYPE_DDR_1_2V)
> > +               err = __mmc_set_signal_voltage(host,
> > + MMC_SIGNAL_VOLTAGE_120);
> >
> > -       mmc_set_timing(host, MMC_TIMING_MMC_DDR52);
> > +       if (err && (card->mmc_avail_type &
> EXT_CSD_CARD_TYPE_DDR_1_8V))
> > +               err = __mmc_set_signal_voltage(host,
> > + MMC_SIGNAL_VOLTAGE_180);
> > +
> > +       /* make sure vccq is 3.3v after switching disaster */
> > +       if (err)
> > +               err = __mmc_set_signal_voltage(host,
> > + MMC_SIGNAL_VOLTAGE_330);
> > +
> > +       if (!err)
> > +               mmc_set_timing(host, MMC_TIMING_MMC_DDR52);
> >
> >         return err;
> >  }
> > --
> > 1.7.10.4
> >

Re: [PATCH v3] mmc: core: try 1.8v signling in ddr mode if host and device

[Jean-Michel Hautbois]

2014-08-15 10:36 GMT+02:00 Dong, Chuanxiao <chuanxiao.dong@intel.com>:
>
>
>> -----Original Message-----
>> From: Ulf Hansson [mailto:ulf.hansson@linaro.org]
>> Sent: Friday, August 15, 2014 4:34 PM
>> To: Dong, Chuanxiao
>> Cc: linux-mmc; chris@printf.org
>> Subject: Re: [PATCH v3] mmc: core: try 1.8v signling in ddr mode if host and
>> device
>>
>> On 15 August 2014 05:28, Chuanxiao Dong <chuanxiao.dong@intel.com>
>> wrote:
>> > Even (e)MMC card can support 3.3v to 1.2v vccq in DDR, but not all
>> > host controller can support this, like some of the SDHCI host which
>> > connect to an eMMC device. Some of these host controller still needs
>> > to use 1.8v vccq for supporting DDR mode.
>> >
>> > So the sequence will be:
>> > if (host and device can both support 1.2v IO)
>> >         use 1.2v IO;
>> > else if (host and device can both support 1.8v IO)
>> >         use 1.8v IO;
>> > so if host and device can only support 3.3v IO, this is the last choice.
>> >
>> > Signed-off-by: Chuanxiao Dong <chuanxiao.dong@intel.com>
>> > Signed-off-by: Yunpeng Gao <yunpeng.gao@intel.com>
>>
>> This looks good to me! But before I queue it for 3.18 I would appreciate if we
>> could get some help in testing this for some various platforms, that support
>> MMC DDR.
>
> Thanks a lot. BTW, this patch is already tested on Intel's platform which can support MMC DDR.

This patch associated with vqmmc-supply and vmmc-supply in the DT is
working for me too on i.MX6.
JM

Re: [PATCH v3] mmc: core: try 1.8v signling in ddr mode if host and device

[Ulf Hansson]

On 2 September 2014 17:31, Jean-Michel Hautbois <jhautbois@gmail.com> wrote:
> 2014-08-15 10:36 GMT+02:00 Dong, Chuanxiao <chuanxiao.dong@intel.com>:
>>
>>
>>> -----Original Message-----
>>> From: Ulf Hansson [mailto:ulf.hansson@linaro.org]
>>> Sent: Friday, August 15, 2014 4:34 PM
>>> To: Dong, Chuanxiao
>>> Cc: linux-mmc; chris@printf.org
>>> Subject: Re: [PATCH v3] mmc: core: try 1.8v signling in ddr mode if host and
>>> device
>>>
>>> On 15 August 2014 05:28, Chuanxiao Dong <chuanxiao.dong@intel.com>
>>> wrote:
>>> > Even (e)MMC card can support 3.3v to 1.2v vccq in DDR, but not all
>>> > host controller can support this, like some of the SDHCI host which
>>> > connect to an eMMC device. Some of these host controller still needs
>>> > to use 1.8v vccq for supporting DDR mode.
>>> >
>>> > So the sequence will be:
>>> > if (host and device can both support 1.2v IO)
>>> >         use 1.2v IO;
>>> > else if (host and device can both support 1.8v IO)
>>> >         use 1.8v IO;
>>> > so if host and device can only support 3.3v IO, this is the last choice.
>>> >
>>> > Signed-off-by: Chuanxiao Dong <chuanxiao.dong@intel.com>
>>> > Signed-off-by: Yunpeng Gao <yunpeng.gao@intel.com>
>>>
>>> This looks good to me! But before I queue it for 3.18 I would appreciate if we
>>> could get some help in testing this for some various platforms, that support
>>> MMC DDR.
>>
>> Thanks a lot. BTW, this patch is already tested on Intel's platform which can support MMC DDR.
>
> This patch associated with vqmmc-supply and vmmc-supply in the DT is
> working for me too on i.MX6.
> JM

Thanks! Applied for next.

I took the liberty of updating the commit msg header to "mmc: core:
Fix sequence for I/O voltage in DDR mode for eMMC", to get a better
description of the patch.

I also added a tested by tag from "JM".

Please tell me if you have any concern with my changes.

Kind regards
Uffe

RE: [PATCH v3] mmc: core: try 1.8v signling in ddr mode if host and device

[Dong, Chuanxiao]

> -----Original Message-----
> From: linux-mmc-owner@vger.kernel.org
> [mailto:linux-mmc-owner@vger.kernel.org] On Behalf Of Ulf Hansson
> Sent: Wednesday, September 03, 2014 3:21 PM
> To: Jean-Michel Hautbois; Dong, Chuanxiao
> Cc: linux-mmc; chris@printf.org
> Subject: Re: [PATCH v3] mmc: core: try 1.8v signling in ddr mode if host and
> device
> 
> On 2 September 2014 17:31, Jean-Michel Hautbois <jhautbois@gmail.com>
> wrote:
> > 2014-08-15 10:36 GMT+02:00 Dong, Chuanxiao
> <chuanxiao.dong@intel.com>:
> >>
> >>
> >>> -----Original Message-----
> >>> From: Ulf Hansson [mailto:ulf.hansson@linaro.org]
> >>> Sent: Friday, August 15, 2014 4:34 PM
> >>> To: Dong, Chuanxiao
> >>> Cc: linux-mmc; chris@printf.org
> >>> Subject: Re: [PATCH v3] mmc: core: try 1.8v signling in ddr mode if
> >>> host and device
> >>>
> >>> On 15 August 2014 05:28, Chuanxiao Dong <chuanxiao.dong@intel.com>
> >>> wrote:
> >>> > Even (e)MMC card can support 3.3v to 1.2v vccq in DDR, but not all
> >>> > host controller can support this, like some of the SDHCI host
> >>> > which connect to an eMMC device. Some of these host controller
> >>> > still needs to use 1.8v vccq for supporting DDR mode.
> >>> >
> >>> > So the sequence will be:
> >>> > if (host and device can both support 1.2v IO)
> >>> >         use 1.2v IO;
> >>> > else if (host and device can both support 1.8v IO)
> >>> >         use 1.8v IO;
> >>> > so if host and device can only support 3.3v IO, this is the last choice.
> >>> >
> >>> > Signed-off-by: Chuanxiao Dong <chuanxiao.dong@intel.com>
> >>> > Signed-off-by: Yunpeng Gao <yunpeng.gao@intel.com>
> >>>
> >>> This looks good to me! But before I queue it for 3.18 I would
> >>> appreciate if we could get some help in testing this for some
> >>> various platforms, that support MMC DDR.
> >>
> >> Thanks a lot. BTW, this patch is already tested on Intel's platform which can
> support MMC DDR.
> >
> > This patch associated with vqmmc-supply and vmmc-supply in the DT is
> > working for me too on i.MX6.
> > JM
> 
> Thanks! Applied for next.
> 
> I took the liberty of updating the commit msg header to "mmc: core:
> Fix sequence for I/O voltage in DDR mode for eMMC", to get a better
> description of the patch.
> 
> I also added a tested by tag from "JM".
> 
> Please tell me if you have any concern with my changes.
No concern from my side.

Thanks JM for testing this patch, and also thanks Ulf for making this patch better :)

Thanks
Chuanxiao

> 
> Kind regards
> Uffe
> --
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