mmc: core: try 1.8v signling in ddr mode if host and device

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 <[email protected]>

Signed-off-by Yunpeng Gao <[email protected]>

---
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(-)

drivers/mmc/core/mmc.c +25 -10

index 793c6f7..8d69671 100644
@@ -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

-----Original Message-----
From: Ulf Hansson [mailto:[email protected]]
Sent: Friday, August 15, 2014 4:34 PM
To: Dong, Chuanxiao
Cc: linux-mmc; [email protected]
Subject: Re: [PATCH v3] mmc: core: try 1.8v signling in ddr mode if host and device

Quoted 12 lines · 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.

Quoted 2 lines

Signed-off-by Chuanxiao Dong <[email protected]>

Signed-off-by Yunpeng Gao <[email protected]>

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

Quoted 3 lines

---
Changelog V2:
- For (e)MMC device switching to DDR mode, try 1.2v singaling first.

Then

drivers/mmc/core/mmc.c static int mmc_select_hs_ddr(struct mmc_card

Quoted 15 lines

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(-)

drivers/mmc/core/mmc.c index renamed from drivers/mmc/core/mmc.c +0 -0

793c6f7..8d69671 100644

drivers/mmc/core/mmc.c +0 -0

@@ -988,19 +988,35 @@ static int mmc_select_hs_ddr(struct mmc_card

*card)

Quoted 24 lines

drivers/mmc/core/mmc.c +13 -5

         * 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);

drivers/mmc/core/mmc.c static int mmc_select_hs_ddr(struct mmc_card *card)

Quoted 10 lines

drivers/mmc/core/mmc.c +5 -4

-               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))

Quoted 16 lines

drivers/mmc/core/mmc.c +10 -1

+               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

Quoted 24 lines

-----Original Message-----
From: Ulf Hansson [mailto:[email protected]]
Sent: Friday, August 15, 2014 4:34 PM
To: Dong, Chuanxiao
Cc: linux-mmc; [email protected]
Subject: Re: [PATCH v3] mmc: core: try 1.8v signling in ddr mode if host and device

Quoted 12 lines · 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.

Quoted 6 lines

Quoted 2 lines

Signed-off-by Chuanxiao Dong <[email protected]>

Signed-off-by Yunpeng Gao <[email protected]>

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.

2014-08-15 10:36 GMT+02:00 Dong, Chuanxiao <[email protected]>:

Quoted 31 lines

Quoted 30 lines

-----Original Message-----
From: Ulf Hansson [mailto:[email protected]]
Sent: Friday, August 15, 2014 4:34 PM
To: Dong, Chuanxiao
Cc: linux-mmc; [email protected]
Subject: Re: [PATCH v3] mmc: core: try 1.8v signling in ddr mode if host and device

Quoted 7 lines · 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)

Quoted 7 lines

        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 <[email protected]>

Signed-off-by Yunpeng Gao <[email protected]>

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.

Quoted 1 line

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

-----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf Of Ulf Hansson
Sent: Wednesday, September 03, 2014 3:21 PM
To: Jean-Michel Hautbois; Dong, Chuanxiao
Cc: linux-mmc; [email protected]
Subject: Re: [PATCH v3] mmc: core: try 1.8v signling in ddr mode if host and device

Quoted 1 line · Jean-Michel Hautbois

2014-08-15 10:36 GMT+02:00 Dong, Chuanxiao

<[email protected]>:

Quoted 24 lines

Quoted 24 lines

Quoted 24 lines

-----Original Message-----
From: Ulf Hansson [mailto:[email protected]]
Sent: Friday, August 15, 2014 4:34 PM
To: Dong, Chuanxiao
Cc: linux-mmc; [email protected]
Subject: Re: [PATCH v3] mmc: core: try 1.8v signling in ddr mode if host and device

Quoted 12 lines · 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.

Quoted 8 lines

Quoted 8 lines

Quoted 6 lines

Quoted 2 lines

Signed-off-by Chuanxiao Dong <[email protected]>

Signed-off-by Yunpeng Gao <[email protected]>

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.

Quoted 4 lines

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
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