* [PATCH v2] mmc: enable Enhance Strobe for HS400.
@ 2015-06-05 2:50 Yi Sun
2015-06-05 21:50 ` Ritesh Harjani
2015-06-12 22:47 ` Venkat Gopalakrishnan
0 siblings, 2 replies; 5+ messages in thread
From: Yi Sun @ 2015-06-05 2:50 UTC (permalink / raw)
To: linux-mmc, ulf.hansson; +Cc: yi.y.sun
Enhance Strobe is defined in v5.1 eMMC spec. This commit
is to implement it.
Normal Strobe signal for HS400 is only provided during
Data Out and CRC Response. While Enhance Strobe is enabled,
Strobe signal is provided during Data Out, CRC Response and
CMD Response.
While enabling Enhance Strobe, the initialization of HS400
does not need enabling HS200 and executing tuning anymore.
This simplifies the HS400 initialization process much.
Per spec, there is a STROBE_SUPPORT added in EXT_CSD register
to indicate that card supports Enhance Strobe or not. If it is
supported, host can enable this feature by enabling the most
significant bit of BUS_WIDTH before set HS_TIMING to HS400.
Signed-off-by: Yi Sun <yi.y.sun@intel.com>
---
drivers/mmc/core/mmc.c | 61 ++++++++++++++++++++++++++++++++++++++++++----
include/linux/mmc/card.h | 1 +
include/linux/mmc/mmc.h | 2 ++
3 files changed, 59 insertions(+), 5 deletions(-)
diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c
index e519e31..c9ef2de 100644
--- a/drivers/mmc/core/mmc.c
+++ b/drivers/mmc/core/mmc.c
@@ -585,6 +585,12 @@ static int mmc_decode_ext_csd(struct mmc_card *card, u8 *ext_csd)
card->ext_csd.ffu_capable =
(ext_csd[EXT_CSD_SUPPORTED_MODE] & 0x1) &&
!(ext_csd[EXT_CSD_FW_CONFIG] & 0x1);
+
+ /* Enhance Strobe is supported since v5.1 which rev should be
+ * 8 but some eMMC devices can support it with rev 7. So handle
+ * Enhance Strobe here.
+ */
+ card->ext_csd.strobe_support = ext_csd[EXT_CSD_STROBE_SUPPORT];
}
out:
return err;
@@ -1049,9 +1055,28 @@ static int mmc_select_hs400(struct mmc_card *card)
/*
* HS400 mode requires 8-bit bus width
*/
- if (!(card->mmc_avail_type & EXT_CSD_CARD_TYPE_HS400 &&
- host->ios.bus_width == MMC_BUS_WIDTH_8))
- return 0;
+ if (card->ext_csd.strobe_support) {
+ if (!(card->mmc_avail_type & EXT_CSD_CARD_TYPE_HS400 &&
+ host->caps & MMC_CAP_8_BIT_DATA))
+ return 0;
+
+ /* For Enhance Strobe flow. For non Enhance Strobe, signal
+ * voltage will not be set.
+ */
+ if (card->mmc_avail_type & EXT_CSD_CARD_TYPE_HS200_1_2V)
+ err = __mmc_set_signal_voltage(host,
+ MMC_SIGNAL_VOLTAGE_120);
+
+ if (err && card->mmc_avail_type & EXT_CSD_CARD_TYPE_HS200_1_8V)
+ err = __mmc_set_signal_voltage(host,
+ MMC_SIGNAL_VOLTAGE_180);
+ if (err)
+ return err;
+ } else {
+ if (!(card->mmc_avail_type & EXT_CSD_CARD_TYPE_HS400 &&
+ host->ios.bus_width == MMC_BUS_WIDTH_8))
+ return 0;
+ }
/*
* Before switching to dual data rate operation for HS400,
@@ -1072,15 +1097,36 @@ static int mmc_select_hs400(struct mmc_card *card)
return err;
}
+ val = EXT_CSD_DDR_BUS_WIDTH_8;
+ if (card->ext_csd.strobe_support)
+ val |= EXT_CSD_BUS_WIDTH_STROBE;
err = mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
EXT_CSD_BUS_WIDTH,
- EXT_CSD_DDR_BUS_WIDTH_8,
+ val,
card->ext_csd.generic_cmd6_time);
if (err) {
pr_err("%s: switch to bus width for hs400 failed, err:%d\n",
mmc_hostname(host), err);
return err;
}
+ if (card->ext_csd.strobe_support) {
+ mmc_set_bus_width(host, MMC_BUS_WIDTH_8);
+ /*
+ * If controller can't handle bus width test,
+ * compare ext_csd previously read in 1 bit mode
+ * against ext_csd at new bus width
+ */
+ if (!(host->caps & MMC_CAP_BUS_WIDTH_TEST))
+ err = mmc_compare_ext_csds(card, MMC_BUS_WIDTH_8);
+ else
+ err = mmc_bus_test(card, MMC_BUS_WIDTH_8);
+
+ if (err) {
+ pr_warn("%s: switch to bus width %d failed\n",
+ mmc_hostname(host), MMC_BUS_WIDTH_8);
+ return err;
+ }
+ }
val = EXT_CSD_TIMING_HS400 |
card->drive_strength << EXT_CSD_DRV_STR_SHIFT;
@@ -1263,7 +1309,12 @@ static int mmc_select_timing(struct mmc_card *card)
if (!mmc_can_ext_csd(card))
goto bus_speed;
- if (card->mmc_avail_type & EXT_CSD_CARD_TYPE_HS200)
+ /* For Enhance Strobe HS400 flow */
+ if (card->ext_csd.strobe_support &&
+ card->mmc_avail_type & EXT_CSD_CARD_TYPE_HS400 &&
+ card->host->caps & MMC_CAP_8_BIT_DATA)
+ err = mmc_select_hs400(card);
+ else if (card->mmc_avail_type & EXT_CSD_CARD_TYPE_HS200)
err = mmc_select_hs200(card);
else if (card->mmc_avail_type & EXT_CSD_CARD_TYPE_HS)
err = mmc_select_hs(card);
diff --git a/include/linux/mmc/card.h b/include/linux/mmc/card.h
index 4d3776d..b793b61 100644
--- a/include/linux/mmc/card.h
+++ b/include/linux/mmc/card.h
@@ -95,6 +95,7 @@ struct mmc_ext_csd {
u8 raw_partition_support; /* 160 */
u8 raw_rpmb_size_mult; /* 168 */
u8 raw_erased_mem_count; /* 181 */
+ u8 strobe_support; /* 184 */
u8 raw_ext_csd_structure; /* 194 */
u8 raw_card_type; /* 196 */
u8 raw_driver_strength; /* 197 */
diff --git a/include/linux/mmc/mmc.h b/include/linux/mmc/mmc.h
index 15f2c4a..a1bb32c 100644
--- a/include/linux/mmc/mmc.h
+++ b/include/linux/mmc/mmc.h
@@ -297,6 +297,7 @@ struct _mmc_csd {
#define EXT_CSD_PART_CONFIG 179 /* R/W */
#define EXT_CSD_ERASED_MEM_CONT 181 /* RO */
#define EXT_CSD_BUS_WIDTH 183 /* R/W */
+#define EXT_CSD_STROBE_SUPPORT 184 /* RO */
#define EXT_CSD_HS_TIMING 185 /* R/W */
#define EXT_CSD_POWER_CLASS 187 /* R/W */
#define EXT_CSD_REV 192 /* RO */
@@ -386,6 +387,7 @@ struct _mmc_csd {
#define EXT_CSD_BUS_WIDTH_8 2 /* Card is in 8 bit mode */
#define EXT_CSD_DDR_BUS_WIDTH_4 5 /* Card is in 4 bit DDR mode */
#define EXT_CSD_DDR_BUS_WIDTH_8 6 /* Card is in 8 bit DDR mode */
+#define EXT_CSD_BUS_WIDTH_STROBE 0x80 /* Card is in 8 bit DDR mode */
#define EXT_CSD_TIMING_BC 0 /* Backwards compatility */
#define EXT_CSD_TIMING_HS 1 /* High speed */
--
1.7.9.5
^ permalink raw reply related [flat|nested] 5+ messages in thread
* Re: [PATCH v2] mmc: enable Enhance Strobe for HS400.
2015-06-05 2:50 [PATCH v2] mmc: enable Enhance Strobe for HS400 Yi Sun
@ 2015-06-05 21:50 ` Ritesh Harjani
2015-06-11 13:58 ` Sun, Yi Y
2015-06-12 22:47 ` Venkat Gopalakrishnan
1 sibling, 1 reply; 5+ messages in thread
From: Ritesh Harjani @ 2015-06-05 21:50 UTC (permalink / raw)
To: Yi Sun; +Cc: linux-mmc, ulf.hansson
Hi Sun,
Did you get to test this feature on any of the target?
On Fri, Jun 5, 2015 at 8:20 AM, Yi Sun <yi.y.sun@intel.com> wrote:
> Enhance Strobe is defined in v5.1 eMMC spec. This commit
> is to implement it.
>
> Normal Strobe signal for HS400 is only provided during
> Data Out and CRC Response. While Enhance Strobe is enabled,
> Strobe signal is provided during Data Out, CRC Response and
> CMD Response.
>
> While enabling Enhance Strobe, the initialization of HS400
> does not need enabling HS200 and executing tuning anymore.
If enhanced strobe is enabled, what about SDHCI_NEEDS_RETUNING flag ?
In case of CRC error, we do execute tuning, but now after support of
enhanced strobe, how will that be taken care of?
> This simplifies the HS400 initialization process much.
>
> Per spec, there is a STROBE_SUPPORT added in EXT_CSD register
> to indicate that card supports Enhance Strobe or not. If it is
> supported, host can enable this feature by enabling the most
> significant bit of BUS_WIDTH before set HS_TIMING to HS400.
enhanced strobe feature also requires support from host controller
side as well. Dont you think we should provide some ops here for that?
>
> Signed-off-by: Yi Sun <yi.y.sun@intel.com>
> ---
> drivers/mmc/core/mmc.c | 61 ++++++++++++++++++++++++++++++++++++++++++----
> include/linux/mmc/card.h | 1 +
> include/linux/mmc/mmc.h | 2 ++
> 3 files changed, 59 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c
> index e519e31..c9ef2de 100644
> --- a/drivers/mmc/core/mmc.c
> +++ b/drivers/mmc/core/mmc.c
> @@ -585,6 +585,12 @@ static int mmc_decode_ext_csd(struct mmc_card *card, u8 *ext_csd)
> card->ext_csd.ffu_capable =
> (ext_csd[EXT_CSD_SUPPORTED_MODE] & 0x1) &&
> !(ext_csd[EXT_CSD_FW_CONFIG] & 0x1);
> +
> + /* Enhance Strobe is supported since v5.1 which rev should be
> + * 8 but some eMMC devices can support it with rev 7. So handle
> + * Enhance Strobe here.
> + */
> + card->ext_csd.strobe_support = ext_csd[EXT_CSD_STROBE_SUPPORT];
> }
> out:
> return err;
> @@ -1049,9 +1055,28 @@ static int mmc_select_hs400(struct mmc_card *card)
> /*
> * HS400 mode requires 8-bit bus width
> */
comment not valid?
> - if (!(card->mmc_avail_type & EXT_CSD_CARD_TYPE_HS400 &&
> - host->ios.bus_width == MMC_BUS_WIDTH_8))
> - return 0;
> + if (card->ext_csd.strobe_support) {
> + if (!(card->mmc_avail_type & EXT_CSD_CARD_TYPE_HS400 &&
> + host->caps & MMC_CAP_8_BIT_DATA))
> + return 0;
> +
> + /* For Enhance Strobe flow. For non Enhance Strobe, signal
> + * voltage will not be set.
> + */
> + if (card->mmc_avail_type & EXT_CSD_CARD_TYPE_HS200_1_2V)
> + err = __mmc_set_signal_voltage(host,
> + MMC_SIGNAL_VOLTAGE_120);
> +
> + if (err && card->mmc_avail_type & EXT_CSD_CARD_TYPE_HS200_1_8V)
> + err = __mmc_set_signal_voltage(host,
> + MMC_SIGNAL_VOLTAGE_180);
> + if (err)
> + return err;
> + } else {
> + if (!(card->mmc_avail_type & EXT_CSD_CARD_TYPE_HS400 &&
> + host->ios.bus_width == MMC_BUS_WIDTH_8))
> + return 0;
> + }
>
> /*
> * Before switching to dual data rate operation for HS400,
> @@ -1072,15 +1097,36 @@ static int mmc_select_hs400(struct mmc_card *card)
> return err;
> }
>
> + val = EXT_CSD_DDR_BUS_WIDTH_8;
> + if (card->ext_csd.strobe_support)
> + val |= EXT_CSD_BUS_WIDTH_STROBE;
> err = mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
> EXT_CSD_BUS_WIDTH,
> - EXT_CSD_DDR_BUS_WIDTH_8,
> + val,
> card->ext_csd.generic_cmd6_time);
> if (err) {
> pr_err("%s: switch to bus width for hs400 failed, err:%d\n",
> mmc_hostname(host), err);
> return err;
> }
> + if (card->ext_csd.strobe_support) {
> + mmc_set_bus_width(host, MMC_BUS_WIDTH_8);
> + /*
> + * If controller can't handle bus width test,
> + * compare ext_csd previously read in 1 bit mode
> + * against ext_csd at new bus width
> + */
> + if (!(host->caps & MMC_CAP_BUS_WIDTH_TEST))
> + err = mmc_compare_ext_csds(card, MMC_BUS_WIDTH_8);
> + else
> + err = mmc_bus_test(card, MMC_BUS_WIDTH_8);
> +
> + if (err) {
> + pr_warn("%s: switch to bus width %d failed\n",
> + mmc_hostname(host), MMC_BUS_WIDTH_8);
> + return err;
> + }
> + }
>
> val = EXT_CSD_TIMING_HS400 |
> card->drive_strength << EXT_CSD_DRV_STR_SHIFT;
> @@ -1263,7 +1309,12 @@ static int mmc_select_timing(struct mmc_card *card)
> if (!mmc_can_ext_csd(card))
> goto bus_speed;
>
> - if (card->mmc_avail_type & EXT_CSD_CARD_TYPE_HS200)
> + /* For Enhance Strobe HS400 flow */
> + if (card->ext_csd.strobe_support &&
> + card->mmc_avail_type & EXT_CSD_CARD_TYPE_HS400 &&
> + card->host->caps & MMC_CAP_8_BIT_DATA)
> + err = mmc_select_hs400(card);
> + else if (card->mmc_avail_type & EXT_CSD_CARD_TYPE_HS200)
> err = mmc_select_hs200(card);
> else if (card->mmc_avail_type & EXT_CSD_CARD_TYPE_HS)
> err = mmc_select_hs(card);
> diff --git a/include/linux/mmc/card.h b/include/linux/mmc/card.h
> index 4d3776d..b793b61 100644
> --- a/include/linux/mmc/card.h
> +++ b/include/linux/mmc/card.h
> @@ -95,6 +95,7 @@ struct mmc_ext_csd {
> u8 raw_partition_support; /* 160 */
> u8 raw_rpmb_size_mult; /* 168 */
> u8 raw_erased_mem_count; /* 181 */
> + u8 strobe_support; /* 184 */
> u8 raw_ext_csd_structure; /* 194 */
> u8 raw_card_type; /* 196 */
> u8 raw_driver_strength; /* 197 */
> diff --git a/include/linux/mmc/mmc.h b/include/linux/mmc/mmc.h
> index 15f2c4a..a1bb32c 100644
> --- a/include/linux/mmc/mmc.h
> +++ b/include/linux/mmc/mmc.h
> @@ -297,6 +297,7 @@ struct _mmc_csd {
> #define EXT_CSD_PART_CONFIG 179 /* R/W */
> #define EXT_CSD_ERASED_MEM_CONT 181 /* RO */
> #define EXT_CSD_BUS_WIDTH 183 /* R/W */
> +#define EXT_CSD_STROBE_SUPPORT 184 /* RO */
> #define EXT_CSD_HS_TIMING 185 /* R/W */
> #define EXT_CSD_POWER_CLASS 187 /* R/W */
> #define EXT_CSD_REV 192 /* RO */
> @@ -386,6 +387,7 @@ struct _mmc_csd {
> #define EXT_CSD_BUS_WIDTH_8 2 /* Card is in 8 bit mode */
> #define EXT_CSD_DDR_BUS_WIDTH_4 5 /* Card is in 4 bit DDR mode */
> #define EXT_CSD_DDR_BUS_WIDTH_8 6 /* Card is in 8 bit DDR mode */
> +#define EXT_CSD_BUS_WIDTH_STROBE 0x80 /* Card is in 8 bit DDR mode */
>
> #define EXT_CSD_TIMING_BC 0 /* Backwards compatility */
> #define EXT_CSD_TIMING_HS 1 /* High speed */
> --
> 1.7.9.5
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-mmc" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html
^ permalink raw reply [flat|nested] 5+ messages in thread
* RE: [PATCH v2] mmc: enable Enhance Strobe for HS400.
2015-06-05 21:50 ` Ritesh Harjani
@ 2015-06-11 13:58 ` Sun, Yi Y
0 siblings, 0 replies; 5+ messages in thread
From: Sun, Yi Y @ 2015-06-11 13:58 UTC (permalink / raw)
To: Ritesh Harjani; +Cc: linux-mmc, ulf.hansson
Hi,
Thanks for review and sorry for late to reply. I am on a business travel.
-----Original Message-----
From: ritesh.harjani@gmail.com [mailto:ritesh.harjani@gmail.com] On Behalf Of Ritesh Harjani
Sent: Saturday, June 06, 2015 5:50 AM
To: Sun, Yi Y
Cc: linux-mmc@vger.kernel.org; ulf.hansson@linaro.org
Subject: Re: [PATCH v2] mmc: enable Enhance Strobe for HS400.
> Hi Sun,
> Did you get to test this feature on any of the target?
Yes, this feature is tested on FPGA board. HS400 initialization pass and read/write work well.
On Fri, Jun 5, 2015 at 8:20 AM, Yi Sun <yi.y.sun@intel.com>> wrote:
>> Enhance Strobe is defined in v5.1 eMMC spec. This commit is to
>> implement it.
>>
>> Normal Strobe signal for HS400 is only provided during Data Out and
>> CRC Response. While Enhance Strobe is enabled, Strobe signal is
>> provided during Data Out, CRC Response and CMD Response.
>>
>> While enabling Enhance Strobe, the initialization of HS400 does not
>> need enabling HS200 and executing tuning anymore.
> If enhanced strobe is enabled, what about SDHCI_NEEDS_RETUNING flag ?
> In case of CRC error, we do execute tuning, but now after support of enhanced strobe, how will that be taken care of?
Per my knowledge, re-tuning is not needed for Enhance Strobe. Otherwise, the eMMC HS400 initialization process should do it too, like HS200. But I really miss something here not to do re-tuning if Enhance Strobe is enabled. I will add it. To be frankly, on FPGA, there is no PM and CRC error happened so I do not verify it. I will also try to simulate some scenarios to verify the process.
>> This simplifies the HS400 initialization process much.
>>
>> Per spec, there is a STROBE_SUPPORT added in EXT_CSD register to
>> indicate that card supports Enhance Strobe or not. If it is supported,
>> host can enable this feature by enabling the most significant bit of
>> BUS_WIDTH before set HS_TIMING to HS400.
> enhanced strobe feature also requires support from host controller side as well. Dont you think we should provide some ops here for that?
Yes, thanks for suggestion!
>>
>> Signed-off-by: Yi Sun <yi.y.sun@intel.com>>
>> ---
>> drivers/mmc/core/mmc.c | 61 ++++++++++++++++++++++++++++++++++++++++++----
>> include/linux/mmc/card.h | 1 +
>> include/linux/mmc/mmc.h | 2 ++
>> 3 files changed, 59 insertions(+), 5 deletions(-)
>>
>> diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c index
>> e519e31..c9ef2de 100644
>> --- a/drivers/mmc/core/mmc.c
>> +++ b/drivers/mmc/core/mmc.c
>> @@ -585,6 +585,12 @@ static int mmc_decode_ext_csd(struct mmc_card *card, u8 *ext_csd)
>> card->ext_csd.ffu_capable =
>> (ext_csd[EXT_CSD_SUPPORTED_MODE] & 0x1) &&
>> !(ext_csd[EXT_CSD_FW_CONFIG] & 0x1);
>> +
>> + /* Enhance Strobe is supported since v5.1 which rev should be
>> + * 8 but some eMMC devices can support it with rev 7. So handle
>> + * Enhance Strobe here.
>> + */
>> + card->ext_csd.strobe_support =
>> + ext_csd[EXT_CSD_STROBE_SUPPORT];
>> }
>> out:
>> return err;
>> @@ -1049,9 +1055,28 @@ static int mmc_select_hs400(struct mmc_card *card)
>> /*
>> * HS400 mode requires 8-bit bus width
>> */
comment not valid?
>> - if (!(card->mmc_avail_type & EXT_CSD_CARD_TYPE_HS400 &&
>> - host->ios.bus_width == MMC_BUS_WIDTH_8))
>> - return 0;
>> + if (card->ext_csd.strobe_support) {
>> + if (!(card->mmc_avail_type & EXT_CSD_CARD_TYPE_HS400 &&
>> + host->caps & MMC_CAP_8_BIT_DATA))
>> + return 0;
>> +
>> + /* For Enhance Strobe flow. For non Enhance Strobe, signal
>> + * voltage will not be set.
>> + */
>> + if (card->mmc_avail_type & EXT_CSD_CARD_TYPE_HS200_1_2V)
>> + err = __mmc_set_signal_voltage(host,
>> + MMC_SIGNAL_VOLTAGE_120);
>> +
>> + if (err && card->mmc_avail_type & EXT_CSD_CARD_TYPE_HS200_1_8V)
>> + err = __mmc_set_signal_voltage(host,
>> + MMC_SIGNAL_VOLTAGE_180);
>> + if (err)
>> + return err;
>> + } else {
>> + if (!(card->mmc_avail_type & EXT_CSD_CARD_TYPE_HS400 &&
>> + host->ios.bus_width == MMC_BUS_WIDTH_8))
>> + return 0;
>> + }
>>
>> /*
>> * Before switching to dual data rate operation for HS400, @@
>> -1072,15 +1097,36 @@ static int mmc_select_hs400(struct mmc_card *card)
>> return err;
>> }
>>
>> + val = EXT_CSD_DDR_BUS_WIDTH_8;
>> + if (card->ext_csd.strobe_support)
>> + val |= EXT_CSD_BUS_WIDTH_STROBE;
>> err = mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
>> EXT_CSD_BUS_WIDTH,
>> - EXT_CSD_DDR_BUS_WIDTH_8,
>> + val,
>> card->ext_csd.generic_cmd6_time);
>> if (err) {
>> pr_err("%s: switch to bus width for hs400 failed, err:%d\n",
>> mmc_hostname(host), err);
>> return err;
>> }
>> + if (card->ext_csd.strobe_support) {
>> + mmc_set_bus_width(host, MMC_BUS_WIDTH_8);
>> + /*
>> + * If controller can't handle bus width test,
>> + * compare ext_csd previously read in 1 bit mode
>> + * against ext_csd at new bus width
>> + */
>> + if (!(host->caps & MMC_CAP_BUS_WIDTH_TEST))
>> + err = mmc_compare_ext_csds(card, MMC_BUS_WIDTH_8);
>> + else
>> + err = mmc_bus_test(card, MMC_BUS_WIDTH_8);
>> +
>> + if (err) {
>> + pr_warn("%s: switch to bus width %d failed\n",
>> + mmc_hostname(host), MMC_BUS_WIDTH_8);
>> + return err;
>> + }
>> + }
>>
>> val = EXT_CSD_TIMING_HS400 |
>> card->drive_strength << EXT_CSD_DRV_STR_SHIFT; @@
>> -1263,7 +1309,12 @@ static int mmc_select_timing(struct mmc_card *card)
>> if (!mmc_can_ext_csd(card))
>> goto bus_speed;
>>
>> - if (card->mmc_avail_type & EXT_CSD_CARD_TYPE_HS200)
>> + /* For Enhance Strobe HS400 flow */
>> + if (card->ext_csd.strobe_support &&
>> + card->mmc_avail_type & EXT_CSD_CARD_TYPE_HS400 &&
>> + card->host->>caps & MMC_CAP_8_BIT_DATA)
>> + err = mmc_select_hs400(card);
>> + else if (card->mmc_avail_type & EXT_CSD_CARD_TYPE_HS200)
>> err = mmc_select_hs200(card);
>> else if (card->mmc_avail_type & EXT_CSD_CARD_TYPE_HS)
>> err = mmc_select_hs(card); diff --git
>> a/include/linux/mmc/card.h b/include/linux/mmc/card.h index
>> 4d3776d..b793b61 100644
>> --- a/include/linux/mmc/card.h
>> +++ b/include/linux/mmc/card.h
>> @@ -95,6 +95,7 @@ struct mmc_ext_csd {
>> u8 raw_partition_support; /* 160 */
>> u8 raw_rpmb_size_mult; /* 168 */
>> u8 raw_erased_mem_count; /* 181 */
>> + u8 strobe_support; /* 184 */
>> u8 raw_ext_csd_structure; /* 194 */
>> u8 raw_card_type; /* 196 */
>> u8 raw_driver_strength; /* 197 */
>> diff --git a/include/linux/mmc/mmc.h b/include/linux/mmc/mmc.h index
>> 15f2c4a..a1bb32c 100644
>> --- a/include/linux/mmc/mmc.h
>> +++ b/include/linux/mmc/mmc.h
>> @@ -297,6 +297,7 @@ struct _mmc_csd {
>> #define EXT_CSD_PART_CONFIG 179 /* R/W */
>> #define EXT_CSD_ERASED_MEM_CONT 181 /* RO */
>> #define EXT_CSD_BUS_WIDTH 183 /* R/W */
>> +#define EXT_CSD_STROBE_SUPPORT 184 /* RO */
>> #define EXT_CSD_HS_TIMING 185 /* R/W */
>> #define EXT_CSD_POWER_CLASS 187 /* R/W */
>> #define EXT_CSD_REV 192 /* RO */
>> @@ -386,6 +387,7 @@ struct _mmc_csd {
>> #define EXT_CSD_BUS_WIDTH_8 2 /* Card is in 8 bit mode */
>> #define EXT_CSD_DDR_BUS_WIDTH_4 5 /* Card is in 4 bit DDR mode */
>> #define EXT_CSD_DDR_BUS_WIDTH_8 6 /* Card is in 8 bit DDR mode */
>> +#define EXT_CSD_BUS_WIDTH_STROBE 0x80 /* Card is in 8 bit DDR mode */
>>
>> #define EXT_CSD_TIMING_BC 0 /* Backwards compatility */
>> #define EXT_CSD_TIMING_HS 1 /* High speed */
>> --
>> 1.7.9.5
>>
>> --
>> To unsubscribe from this list: send the line "unsubscribe linux-mmc"
>> in the body of a message to majordomo@vger.kernel.org More majordomo
>> info at http://vger.kernel.org/majordomo-info.html
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH v2] mmc: enable Enhance Strobe for HS400.
2015-06-05 2:50 [PATCH v2] mmc: enable Enhance Strobe for HS400 Yi Sun
2015-06-05 21:50 ` Ritesh Harjani
@ 2015-06-12 22:47 ` Venkat Gopalakrishnan
2015-07-01 3:15 ` Sun, Yi Y
1 sibling, 1 reply; 5+ messages in thread
From: Venkat Gopalakrishnan @ 2015-06-12 22:47 UTC (permalink / raw)
Cc: linux-mmc, ulf.hansson, yi.y.sun
Hi Yi,
I tested your patch on msm platform and found few issues. Please see my
comments inline.
On Thu, June 4, 2015 7:50 pm, Yi Sun wrote:
> Enhance Strobe is defined in v5.1 eMMC spec. This commit
Please replace "Enhance Strobe" to "Enhanced Strobe" as per spec
throughout the documentation and code.
> is to implement it.
>
> Normal Strobe signal for HS400 is only provided during
> Data Out and CRC Response. While Enhance Strobe is enabled,
> Strobe signal is provided during Data Out, CRC Response and
> CMD Response.
>
> While enabling Enhance Strobe, the initialization of HS400
> does not need enabling HS200 and executing tuning anymore.
> This simplifies the HS400 initialization process much.
>
> Per spec, there is a STROBE_SUPPORT added in EXT_CSD register
> to indicate that card supports Enhance Strobe or not. If it is
> supported, host can enable this feature by enabling the most
> significant bit of BUS_WIDTH before set HS_TIMING to HS400.
>
> Signed-off-by: Yi Sun <yi.y.sun@intel.com>
> ---
> drivers/mmc/core/mmc.c | 61
> ++++++++++++++++++++++++++++++++++++++++++----
> include/linux/mmc/card.h | 1 +
> include/linux/mmc/mmc.h | 2 ++
> 3 files changed, 59 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c
> index e519e31..c9ef2de 100644
> --- a/drivers/mmc/core/mmc.c
> +++ b/drivers/mmc/core/mmc.c
> @@ -585,6 +585,12 @@ static int mmc_decode_ext_csd(struct mmc_card *card,
> u8 *ext_csd)
> card->ext_csd.ffu_capable =
> (ext_csd[EXT_CSD_SUPPORTED_MODE] & 0x1) &&
> !(ext_csd[EXT_CSD_FW_CONFIG] & 0x1);
> +
> + /* Enhance Strobe is supported since v5.1 which rev should be
> + * 8 but some eMMC devices can support it with rev 7. So handle
> + * Enhance Strobe here.
> + */
> + card->ext_csd.strobe_support = ext_csd[EXT_CSD_STROBE_SUPPORT];
> }
> out:
> return err;
> @@ -1049,9 +1055,28 @@ static int mmc_select_hs400(struct mmc_card *card)
> /*
> * HS400 mode requires 8-bit bus width
> */
> - if (!(card->mmc_avail_type & EXT_CSD_CARD_TYPE_HS400 &&
> - host->ios.bus_width == MMC_BUS_WIDTH_8))
> - return 0;
> + if (card->ext_csd.strobe_support) {
> + if (!(card->mmc_avail_type & EXT_CSD_CARD_TYPE_HS400 &&
> + host->caps & MMC_CAP_8_BIT_DATA))
> + return 0;
> +
> + /* For Enhance Strobe flow. For non Enhance Strobe, signal
> + * voltage will not be set.
> + */
> + if (card->mmc_avail_type & EXT_CSD_CARD_TYPE_HS200_1_2V)
> + err = __mmc_set_signal_voltage(host,
> + MMC_SIGNAL_VOLTAGE_120);
> +
> + if (err && card->mmc_avail_type & EXT_CSD_CARD_TYPE_HS200_1_8V)
> + err = __mmc_set_signal_voltage(host,
> + MMC_SIGNAL_VOLTAGE_180);
> + if (err)
> + return err;
> + } else {
> + if (!(card->mmc_avail_type & EXT_CSD_CARD_TYPE_HS400 &&
> + host->ios.bus_width == MMC_BUS_WIDTH_8))
> + return 0;
> + }
>
> /*
> * Before switching to dual data rate operation for HS400,
> @@ -1072,15 +1097,36 @@ static int mmc_select_hs400(struct mmc_card *card)
> return err;
> }
>
We can use mmc_select_bus_width to set 8 bit bus width here, see my
comment below.
> + val = EXT_CSD_DDR_BUS_WIDTH_8;
> + if (card->ext_csd.strobe_support)
> + val |= EXT_CSD_BUS_WIDTH_STROBE;
> err = mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
> EXT_CSD_BUS_WIDTH,
> - EXT_CSD_DDR_BUS_WIDTH_8,
> + val,
> card->ext_csd.generic_cmd6_time);
> if (err) {
> pr_err("%s: switch to bus width for hs400 failed, err:%d\n",
> mmc_hostname(host), err);
> return err;
> }
> + if (card->ext_csd.strobe_support) {
> + mmc_set_bus_width(host, MMC_BUS_WIDTH_8);
> + /*
> + * If controller can't handle bus width test,
> + * compare ext_csd previously read in 1 bit mode
> + * against ext_csd at new bus width
> + */
> + if (!(host->caps & MMC_CAP_BUS_WIDTH_TEST))
> + err = mmc_compare_ext_csds(card, MMC_BUS_WIDTH_8);
Reading the ext csd here fails with CRC error since the card is switched
to DDR bus width above while the host remains in SDR. We should have both
the host and card in the same timing/bus width before reading data from
card.
I would recommend using mmc_select_bus_width after switching the timing to
HS instead of replicating the code in this if block.
> + else
> + err = mmc_bus_test(card, MMC_BUS_WIDTH_8);
> +
> + if (err) {
> + pr_warn("%s: switch to bus width %d failed\n",
> + mmc_hostname(host), MMC_BUS_WIDTH_8);
> + return err;
> + }
> + }
>
Please do add a call to host ops for hosts that need and provide
additional programming.
> val = EXT_CSD_TIMING_HS400 |
> card->drive_strength << EXT_CSD_DRV_STR_SHIFT;
> @@ -1263,7 +1309,12 @@ static int mmc_select_timing(struct mmc_card *card)
> if (!mmc_can_ext_csd(card))
> goto bus_speed;
>
> - if (card->mmc_avail_type & EXT_CSD_CARD_TYPE_HS200)
> + /* For Enhance Strobe HS400 flow */
> + if (card->ext_csd.strobe_support &&
> + card->mmc_avail_type & EXT_CSD_CARD_TYPE_HS400 &&
> + card->host->caps & MMC_CAP_8_BIT_DATA)
> + err = mmc_select_hs400(card);
> + else if (card->mmc_avail_type & EXT_CSD_CARD_TYPE_HS200)
> err = mmc_select_hs200(card);
> else if (card->mmc_avail_type & EXT_CSD_CARD_TYPE_HS)
> err = mmc_select_hs(card);
> diff --git a/include/linux/mmc/card.h b/include/linux/mmc/card.h
> index 4d3776d..b793b61 100644
> --- a/include/linux/mmc/card.h
> +++ b/include/linux/mmc/card.h
> @@ -95,6 +95,7 @@ struct mmc_ext_csd {
> u8 raw_partition_support; /* 160 */
> u8 raw_rpmb_size_mult; /* 168 */
> u8 raw_erased_mem_count; /* 181 */
> + u8 strobe_support; /* 184 */
> u8 raw_ext_csd_structure; /* 194 */
> u8 raw_card_type; /* 196 */
> u8 raw_driver_strength; /* 197 */
> diff --git a/include/linux/mmc/mmc.h b/include/linux/mmc/mmc.h
> index 15f2c4a..a1bb32c 100644
> --- a/include/linux/mmc/mmc.h
> +++ b/include/linux/mmc/mmc.h
> @@ -297,6 +297,7 @@ struct _mmc_csd {
> #define EXT_CSD_PART_CONFIG 179 /* R/W */
> #define EXT_CSD_ERASED_MEM_CONT 181 /* RO */
> #define EXT_CSD_BUS_WIDTH 183 /* R/W */
> +#define EXT_CSD_STROBE_SUPPORT 184 /* RO */
> #define EXT_CSD_HS_TIMING 185 /* R/W */
> #define EXT_CSD_POWER_CLASS 187 /* R/W */
> #define EXT_CSD_REV 192 /* RO */
> @@ -386,6 +387,7 @@ struct _mmc_csd {
> #define EXT_CSD_BUS_WIDTH_8 2 /* Card is in 8 bit mode */
> #define EXT_CSD_DDR_BUS_WIDTH_4 5 /* Card is in 4 bit DDR mode */
> #define EXT_CSD_DDR_BUS_WIDTH_8 6 /* Card is in 8 bit DDR mode */
> +#define EXT_CSD_BUS_WIDTH_STROBE 0x80 /* Card is in 8 bit DDR mode */
>
> #define EXT_CSD_TIMING_BC 0 /* Backwards compatility */
> #define EXT_CSD_TIMING_HS 1 /* High speed */
> --
> 1.7.9.5
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-mmc" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html
>
--
Venkat Gopalakrishnan,
Employee of Qualcomm Innovation Center, Inc.
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux
Foundation Collaborative Project
^ permalink raw reply [flat|nested] 5+ messages in thread
* RE: [PATCH v2] mmc: enable Enhance Strobe for HS400.
2015-06-12 22:47 ` Venkat Gopalakrishnan
@ 2015-07-01 3:15 ` Sun, Yi Y
0 siblings, 0 replies; 5+ messages in thread
From: Sun, Yi Y @ 2015-07-01 3:15 UTC (permalink / raw)
To: Venkat Gopalakrishnan; +Cc: linux-mmc, ulf.hansson
Hi,
Sorry for late and thanks a lot for your test and suggestions! I have completed the business travel and will check them in detail.
BRs,
Sun Yi
-----Original Message-----
From: Venkat Gopalakrishnan [mailto:venkatg@codeaurora.org]
Sent: Saturday, June 13, 2015 6:48 AM
To: Sun, Yi Y
Cc: linux-mmc@vger.kernel.org; ulf.hansson@linaro.org; Sun, Yi Y
Subject: Re: [PATCH v2] mmc: enable Enhance Strobe for HS400.
Hi Yi,
I tested your patch on msm platform and found few issues. Please see my comments inline.
On Thu, June 4, 2015 7:50 pm, Yi Sun wrote:
> Enhance Strobe is defined in v5.1 eMMC spec. This commit
Please replace "Enhance Strobe" to "Enhanced Strobe" as per spec throughout the documentation and code.
> is to implement it.
>
> Normal Strobe signal for HS400 is only provided during Data Out and
> CRC Response. While Enhance Strobe is enabled, Strobe signal is
> provided during Data Out, CRC Response and CMD Response.
>
> While enabling Enhance Strobe, the initialization of HS400 does not
> need enabling HS200 and executing tuning anymore.
> This simplifies the HS400 initialization process much.
>
> Per spec, there is a STROBE_SUPPORT added in EXT_CSD register to
> indicate that card supports Enhance Strobe or not. If it is supported,
> host can enable this feature by enabling the most significant bit of
> BUS_WIDTH before set HS_TIMING to HS400.
>
> Signed-off-by: Yi Sun <yi.y.sun@intel.com>
> ---
> drivers/mmc/core/mmc.c | 61
> ++++++++++++++++++++++++++++++++++++++++++----
> include/linux/mmc/card.h | 1 +
> include/linux/mmc/mmc.h | 2 ++
> 3 files changed, 59 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c index
> e519e31..c9ef2de 100644
> --- a/drivers/mmc/core/mmc.c
> +++ b/drivers/mmc/core/mmc.c
> @@ -585,6 +585,12 @@ static int mmc_decode_ext_csd(struct mmc_card
> *card,
> u8 *ext_csd)
> card->ext_csd.ffu_capable =
> (ext_csd[EXT_CSD_SUPPORTED_MODE] & 0x1) &&
> !(ext_csd[EXT_CSD_FW_CONFIG] & 0x1);
> +
> + /* Enhance Strobe is supported since v5.1 which rev should be
> + * 8 but some eMMC devices can support it with rev 7. So handle
> + * Enhance Strobe here.
> + */
> + card->ext_csd.strobe_support = ext_csd[EXT_CSD_STROBE_SUPPORT];
> }
> out:
> return err;
> @@ -1049,9 +1055,28 @@ static int mmc_select_hs400(struct mmc_card *card)
> /*
> * HS400 mode requires 8-bit bus width
> */
> - if (!(card->mmc_avail_type & EXT_CSD_CARD_TYPE_HS400 &&
> - host->ios.bus_width == MMC_BUS_WIDTH_8))
> - return 0;
> + if (card->ext_csd.strobe_support) {
> + if (!(card->mmc_avail_type & EXT_CSD_CARD_TYPE_HS400 &&
> + host->caps & MMC_CAP_8_BIT_DATA))
> + return 0;
> +
> + /* For Enhance Strobe flow. For non Enhance Strobe, signal
> + * voltage will not be set.
> + */
> + if (card->mmc_avail_type & EXT_CSD_CARD_TYPE_HS200_1_2V)
> + err = __mmc_set_signal_voltage(host,
> + MMC_SIGNAL_VOLTAGE_120);
> +
> + if (err && card->mmc_avail_type & EXT_CSD_CARD_TYPE_HS200_1_8V)
> + err = __mmc_set_signal_voltage(host,
> + MMC_SIGNAL_VOLTAGE_180);
> + if (err)
> + return err;
> + } else {
> + if (!(card->mmc_avail_type & EXT_CSD_CARD_TYPE_HS400 &&
> + host->ios.bus_width == MMC_BUS_WIDTH_8))
> + return 0;
> + }
>
> /*
> * Before switching to dual data rate operation for HS400, @@
> -1072,15 +1097,36 @@ static int mmc_select_hs400(struct mmc_card *card)
> return err;
> }
>
We can use mmc_select_bus_width to set 8 bit bus width here, see my comment below.
> + val = EXT_CSD_DDR_BUS_WIDTH_8;
> + if (card->ext_csd.strobe_support)
> + val |= EXT_CSD_BUS_WIDTH_STROBE;
> err = mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
> EXT_CSD_BUS_WIDTH,
> - EXT_CSD_DDR_BUS_WIDTH_8,
> + val,
> card->ext_csd.generic_cmd6_time);
> if (err) {
> pr_err("%s: switch to bus width for hs400 failed, err:%d\n",
> mmc_hostname(host), err);
> return err;
> }
> + if (card->ext_csd.strobe_support) {
> + mmc_set_bus_width(host, MMC_BUS_WIDTH_8);
> + /*
> + * If controller can't handle bus width test,
> + * compare ext_csd previously read in 1 bit mode
> + * against ext_csd at new bus width
> + */
> + if (!(host->caps & MMC_CAP_BUS_WIDTH_TEST))
> + err = mmc_compare_ext_csds(card, MMC_BUS_WIDTH_8);
Reading the ext csd here fails with CRC error since the card is switched to DDR bus width above while the host remains in SDR. We should have both the host and card in the same timing/bus width before reading data from card.
I would recommend using mmc_select_bus_width after switching the timing to HS instead of replicating the code in this if block.
> + else
> + err = mmc_bus_test(card, MMC_BUS_WIDTH_8);
> +
> + if (err) {
> + pr_warn("%s: switch to bus width %d failed\n",
> + mmc_hostname(host), MMC_BUS_WIDTH_8);
> + return err;
> + }
> + }
>
Please do add a call to host ops for hosts that need and provide additional programming.
> val = EXT_CSD_TIMING_HS400 |
> card->drive_strength << EXT_CSD_DRV_STR_SHIFT; @@ -1263,7
> +1309,12 @@ static int mmc_select_timing(struct mmc_card *card)
> if (!mmc_can_ext_csd(card))
> goto bus_speed;
>
> - if (card->mmc_avail_type & EXT_CSD_CARD_TYPE_HS200)
> + /* For Enhance Strobe HS400 flow */
> + if (card->ext_csd.strobe_support &&
> + card->mmc_avail_type & EXT_CSD_CARD_TYPE_HS400 &&
> + card->host->caps & MMC_CAP_8_BIT_DATA)
> + err = mmc_select_hs400(card);
> + else if (card->mmc_avail_type & EXT_CSD_CARD_TYPE_HS200)
> err = mmc_select_hs200(card);
> else if (card->mmc_avail_type & EXT_CSD_CARD_TYPE_HS)
> err = mmc_select_hs(card);
> diff --git a/include/linux/mmc/card.h b/include/linux/mmc/card.h index
> 4d3776d..b793b61 100644
> --- a/include/linux/mmc/card.h
> +++ b/include/linux/mmc/card.h
> @@ -95,6 +95,7 @@ struct mmc_ext_csd {
> u8 raw_partition_support; /* 160 */
> u8 raw_rpmb_size_mult; /* 168 */
> u8 raw_erased_mem_count; /* 181 */
> + u8 strobe_support; /* 184 */
> u8 raw_ext_csd_structure; /* 194 */
> u8 raw_card_type; /* 196 */
> u8 raw_driver_strength; /* 197 */
> diff --git a/include/linux/mmc/mmc.h b/include/linux/mmc/mmc.h index
> 15f2c4a..a1bb32c 100644
> --- a/include/linux/mmc/mmc.h
> +++ b/include/linux/mmc/mmc.h
> @@ -297,6 +297,7 @@ struct _mmc_csd {
> #define EXT_CSD_PART_CONFIG 179 /* R/W */
> #define EXT_CSD_ERASED_MEM_CONT 181 /* RO */
> #define EXT_CSD_BUS_WIDTH 183 /* R/W */
> +#define EXT_CSD_STROBE_SUPPORT 184 /* RO */
> #define EXT_CSD_HS_TIMING 185 /* R/W */
> #define EXT_CSD_POWER_CLASS 187 /* R/W */
> #define EXT_CSD_REV 192 /* RO */
> @@ -386,6 +387,7 @@ struct _mmc_csd {
> #define EXT_CSD_BUS_WIDTH_8 2 /* Card is in 8 bit mode */
> #define EXT_CSD_DDR_BUS_WIDTH_4 5 /* Card is in 4 bit DDR mode */
> #define EXT_CSD_DDR_BUS_WIDTH_8 6 /* Card is in 8 bit DDR mode */
> +#define EXT_CSD_BUS_WIDTH_STROBE 0x80 /* Card is in 8 bit DDR mode */
>
> #define EXT_CSD_TIMING_BC 0 /* Backwards compatility */
> #define EXT_CSD_TIMING_HS 1 /* High speed */
> --
> 1.7.9.5
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-mmc"
> in the body of a message to majordomo@vger.kernel.org More majordomo
> info at http://vger.kernel.org/majordomo-info.html
>
--
Venkat Gopalakrishnan,
Employee of Qualcomm Innovation Center, Inc.
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project
^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2015-07-01 3:15 UTC | newest]
Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2015-06-05 2:50 [PATCH v2] mmc: enable Enhance Strobe for HS400 Yi Sun
2015-06-05 21:50 ` Ritesh Harjani
2015-06-11 13:58 ` Sun, Yi Y
2015-06-12 22:47 ` Venkat Gopalakrishnan
2015-07-01 3:15 ` Sun, Yi Y
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