2019-05-06 17:02:49

by Scott Branden

Subject: [PATCH 0/2] mmc: sdhci-iproc: fixes for HS50 data hold time

This patch series fixes data hold timing issues for various sdhci-iproc
ip blocks that do not meet the HS50 data hold time. NO_HISPD bit is set
in quirks.

Trac Hoang (2):
mmc: sdhci-iproc: cygnus: Set NO_HISPD bit to fix HS50 data hold time
problem
mmc: sdhci-iproc: Set NO_HISPD bit to fix HS50 data hold time problem

drivers/mmc/host/sdhci-iproc.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)

--
2.17.1

2019-05-06 17:02:56

by Scott Branden

Subject: [PATCH 1/2] mmc: sdhci-iproc: cygnus: Set NO_HISPD bit to fix HS50 data hold time problem

From: Trac Hoang <[email protected]>

The iproc host eMMC/SD controller hold time does not meet the
specification in the HS50 mode. This problem can be mitigated
by disabling the HISPD bit; thus forcing the controller output
data to be driven on the falling clock edges rather than the
rising clock edges.

This change applies only to the Cygnus platform.

Fixes: c833e92bbb60 ("mmc: sdhci-iproc: support standard byte register accesses")
Signed-off-by: Trac Hoang <[email protected]>
Signed-off-by: Scott Branden <[email protected]>
---
drivers/mmc/host/sdhci-iproc.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/mmc/host/sdhci-iproc.c b/drivers/mmc/host/sdhci-iproc.c
index 9d12c06c7fd6..9d4071c41c94 100644
--- a/drivers/mmc/host/sdhci-iproc.c
+++ b/drivers/mmc/host/sdhci-iproc.c
@@ -196,7 +196,8 @@ static const struct sdhci_ops sdhci_iproc_32only_ops = {
};

static const struct sdhci_pltfm_data sdhci_iproc_cygnus_pltfm_data = {
- .quirks = SDHCI_QUIRK_DATA_TIMEOUT_USES_SDCLK,
+ .quirks = SDHCI_QUIRK_DATA_TIMEOUT_USES_SDCLK |
+ SDHCI_QUIRK_NO_HISPD_BIT,
.quirks2 = SDHCI_QUIRK2_ACMD23_BROKEN | SDHCI_QUIRK2_HOST_OFF_CARD_ON,
.ops = &sdhci_iproc_32only_ops,
};
--
2.17.1

2019-05-06 17:03:17

by Scott Branden

Subject: [PATCH 2/2] mmc: sdhci-iproc: Set NO_HISPD bit to fix HS50 data hold time problem

From: Trac Hoang <[email protected]>

The iproc host eMMC/SD controller hold time does not meet the
specification in the HS50 mode. This problem can be mitigated
by disabling the HISPD bit; thus forcing the controller output
data to be driven on the falling clock edges rather than the
rising clock edges.

Fixes: f5f968f2371c ("mmc: sdhci-iproc: suppress spurious interrupt with Multiblock read")
Signed-off-by: Trac Hoang <[email protected]>
Signed-off-by: Scott Branden <[email protected]>
---
drivers/mmc/host/sdhci-iproc.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/mmc/host/sdhci-iproc.c b/drivers/mmc/host/sdhci-iproc.c
index 9d4071c41c94..2feb4ef32035 100644
--- a/drivers/mmc/host/sdhci-iproc.c
+++ b/drivers/mmc/host/sdhci-iproc.c
@@ -220,7 +220,8 @@ static const struct sdhci_iproc_data iproc_cygnus_data = {

static const struct sdhci_pltfm_data sdhci_iproc_pltfm_data = {
.quirks = SDHCI_QUIRK_DATA_TIMEOUT_USES_SDCLK |
- SDHCI_QUIRK_MULTIBLOCK_READ_ACMD12,
+ SDHCI_QUIRK_MULTIBLOCK_READ_ACMD12 |
+ SDHCI_QUIRK_NO_HISPD_BIT,
.quirks2 = SDHCI_QUIRK2_ACMD23_BROKEN,
.ops = &sdhci_iproc_ops,
};
--
2.17.1

2019-05-07 06:32:37

by Adrian Hunter

Subject: Re: [PATCH 2/2] mmc: sdhci-iproc: Set NO_HISPD bit to fix HS50 data hold time problem

On 6/05/19 8:01 PM, Scott Branden wrote:
> From: Trac Hoang <[email protected]>
>
> The iproc host eMMC/SD controller hold time does not meet the
> specification in the HS50 mode. This problem can be mitigated
> by disabling the HISPD bit; thus forcing the controller output
> data to be driven on the falling clock edges rather than the
> rising clock edges.
>
> Fixes: f5f968f2371c ("mmc: sdhci-iproc: suppress spurious interrupt with Multiblock read")

Is this fixes tag correct, because it doesn't seem related. Maybe explain
that in the commit message.

> Signed-off-by: Trac Hoang <[email protected]>
> Signed-off-by: Scott Branden <[email protected]>
> ---
> drivers/mmc/host/sdhci-iproc.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/mmc/host/sdhci-iproc.c b/drivers/mmc/host/sdhci-iproc.c
> index 9d4071c41c94..2feb4ef32035 100644
> --- a/drivers/mmc/host/sdhci-iproc.c
> +++ b/drivers/mmc/host/sdhci-iproc.c
> @@ -220,7 +220,8 @@ static const struct sdhci_iproc_data iproc_cygnus_data = {
>
> static const struct sdhci_pltfm_data sdhci_iproc_pltfm_data = {
> .quirks = SDHCI_QUIRK_DATA_TIMEOUT_USES_SDCLK |
> - SDHCI_QUIRK_MULTIBLOCK_READ_ACMD12,
> + SDHCI_QUIRK_MULTIBLOCK_READ_ACMD12 |
> + SDHCI_QUIRK_NO_HISPD_BIT,
> .quirks2 = SDHCI_QUIRK2_ACMD23_BROKEN,
> .ops = &sdhci_iproc_ops,
> };
>

2019-05-07 06:34:15

by Adrian Hunter

Subject: Re: [PATCH 1/2] mmc: sdhci-iproc: cygnus: Set NO_HISPD bit to fix HS50 data hold time problem

On 6/05/19 8:01 PM, Scott Branden wrote:
> From: Trac Hoang <[email protected]>
>
> The iproc host eMMC/SD controller hold time does not meet the
> specification in the HS50 mode. This problem can be mitigated
> by disabling the HISPD bit; thus forcing the controller output
> data to be driven on the falling clock edges rather than the
> rising clock edges.
>
> This change applies only to the Cygnus platform.
>
> Fixes: c833e92bbb60 ("mmc: sdhci-iproc: support standard byte register accesses")
> Signed-off-by: Trac Hoang <[email protected]>
> Signed-off-by: Scott Branden <[email protected]>

Acked-by: Adrian Hunter <[email protected]>

> ---
> drivers/mmc/host/sdhci-iproc.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/mmc/host/sdhci-iproc.c b/drivers/mmc/host/sdhci-iproc.c
> index 9d12c06c7fd6..9d4071c41c94 100644
> --- a/drivers/mmc/host/sdhci-iproc.c
> +++ b/drivers/mmc/host/sdhci-iproc.c
> @@ -196,7 +196,8 @@ static const struct sdhci_ops sdhci_iproc_32only_ops = {
> };
>
> static const struct sdhci_pltfm_data sdhci_iproc_cygnus_pltfm_data = {
> - .quirks = SDHCI_QUIRK_DATA_TIMEOUT_USES_SDCLK,
> + .quirks = SDHCI_QUIRK_DATA_TIMEOUT_USES_SDCLK |
> + SDHCI_QUIRK_NO_HISPD_BIT,
> .quirks2 = SDHCI_QUIRK2_ACMD23_BROKEN | SDHCI_QUIRK2_HOST_OFF_CARD_ON,
> .ops = &sdhci_iproc_32only_ops,
> };
>

2019-05-07 22:49:01

by Scott Branden

Subject: Re: [PATCH 2/2] mmc: sdhci-iproc: Set NO_HISPD bit to fix HS50 data hold time problem

Hi Adrian,

On 2019-05-06 11:31 p.m., Adrian Hunter wrote:
> On 6/05/19 8:01 PM, Scott Branden wrote:
>> From: Trac Hoang <[email protected]>
>>
>> The iproc host eMMC/SD controller hold time does not meet the
>> specification in the HS50 mode. This problem can be mitigated
>> by disabling the HISPD bit; thus forcing the controller output
>> data to be driven on the falling clock edges rather than the
>> rising clock edges.
>>
>> Fixes: f5f968f2371c ("mmc: sdhci-iproc: suppress spurious interrupt with Multiblock read")
> Is this fixes tag correct, because it doesn't seem related. Maybe explain
> that in the commit message.

I chose this tag to assist stable kernel maintainers so that the change
does not produce merge conflicts backporting to older kernel versions.

In reality, the timing bug existed since the driver was first introduced
but there is no need for this driver to be supported in kernel versions
that old.

Do you want me to add such to the commit message?

>
>> Signed-off-by: Trac Hoang <[email protected]>
>> Signed-off-by: Scott Branden <[email protected]>
>> ---
>> drivers/mmc/host/sdhci-iproc.c | 3 ++-
>> 1 file changed, 2 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/mmc/host/sdhci-iproc.c b/drivers/mmc/host/sdhci-iproc.c
>> index 9d4071c41c94..2feb4ef32035 100644
>> --- a/drivers/mmc/host/sdhci-iproc.c
>> +++ b/drivers/mmc/host/sdhci-iproc.c
>> @@ -220,7 +220,8 @@ static const struct sdhci_iproc_data iproc_cygnus_data = {
>>
>> static const struct sdhci_pltfm_data sdhci_iproc_pltfm_data = {
>> .quirks = SDHCI_QUIRK_DATA_TIMEOUT_USES_SDCLK |
>> - SDHCI_QUIRK_MULTIBLOCK_READ_ACMD12,
>> + SDHCI_QUIRK_MULTIBLOCK_READ_ACMD12 |
>> + SDHCI_QUIRK_NO_HISPD_BIT,
>> .quirks2 = SDHCI_QUIRK2_ACMD23_BROKEN,
>> .ops = &sdhci_iproc_ops,
>> };
>>

2019-05-08 06:03:05

by Adrian Hunter

Subject: Re: [PATCH 2/2] mmc: sdhci-iproc: Set NO_HISPD bit to fix HS50 data hold time problem

On 8/05/19 1:46 AM, Scott Branden wrote:
> Hi Adrian,
>
> On 2019-05-06 11:31 p.m., Adrian Hunter wrote:
>> On 6/05/19 8:01 PM, Scott Branden wrote:
>>> From: Trac Hoang <[email protected]>
>>>
>>> The iproc host eMMC/SD controller hold time does not meet the
>>> specification in the HS50 mode.  This problem can be mitigated
>>> by disabling the HISPD bit; thus forcing the controller output
>>> data to be driven on the falling clock edges rather than the
>>> rising clock edges.
>>>
>>> Fixes: f5f968f2371c ("mmc: sdhci-iproc: suppress spurious interrupt with
>>> Multiblock read")
>> Is this fixes tag correct, because it doesn't seem related.  Maybe explain
>> that in the commit message.
>
> I chose this tag to assist stable kernel maintainers so that the change does
> not produce merge conflicts backporting to older kernel versions.
>
> In reality, the timing bug existed since the driver was first introduced but
> there is no need for this driver to be supported in kernel versions that old.

You don't need to use the Fixes tag for that. You can put it on the Cc line
e.g.

Cc: [email protected] # v4.12+

> Do you want me to add such to the commit message?

Yes please.

>
>>
>>> Signed-off-by: Trac Hoang <[email protected]>
>>> Signed-off-by: Scott Branden <[email protected]>
>>> ---
>>>   drivers/mmc/host/sdhci-iproc.c | 3 ++-
>>>   1 file changed, 2 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/drivers/mmc/host/sdhci-iproc.c b/drivers/mmc/host/sdhci-iproc.c
>>> index 9d4071c41c94..2feb4ef32035 100644
>>> --- a/drivers/mmc/host/sdhci-iproc.c
>>> +++ b/drivers/mmc/host/sdhci-iproc.c
>>> @@ -220,7 +220,8 @@ static const struct sdhci_iproc_data
>>> iproc_cygnus_data = {
>>>     static const struct sdhci_pltfm_data sdhci_iproc_pltfm_data = {
>>>       .quirks = SDHCI_QUIRK_DATA_TIMEOUT_USES_SDCLK |
>>> -          SDHCI_QUIRK_MULTIBLOCK_READ_ACMD12,
>>> +          SDHCI_QUIRK_MULTIBLOCK_READ_ACMD12 |
>>> +          SDHCI_QUIRK_NO_HISPD_BIT,
>>>       .quirks2 = SDHCI_QUIRK2_ACMD23_BROKEN,
>>>       .ops = &sdhci_iproc_ops,
>>>   };
>>>
>