2019-05-08 16:42:13

by Scott Branden

Subject: [PATCH v2 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.

Changes from v1:
- Change fixes tag to Cc: [email protected] to specify version to backport to

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

2019-05-08 17:51:28

by Scott Branden

Subject: [PATCH v2 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.

Cc: [email protected] # v4.12+
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,
};
--
2.17.1

2019-05-08 17:51:40

by Scott Branden

Subject: [PATCH v2 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.

Cc: [email protected] # v4.12+
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

2019-05-09 06:17:44

by Adrian Hunter

Subject: Re: [PATCH v2 2/2] mmc: sdhci-iproc: Set NO_HISPD bit to fix HS50 data hold time problem

On 8/05/19 7:40 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.

You should add your stable comments as well i.e.

Scott chose this tag (v4.12+) 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.

>
> Cc: [email protected] # v4.12+
> 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 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,
> };
>