[1/3] dt-bindings: mmc: meson-gx: add ddr-access-quirk property
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Message ID 20190513091548.16674-2-narmstrong@baylibre.com
State Superseded
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  • [1/3] dt-bindings: mmc: meson-gx: add ddr-access-quirk property
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Commit Message

Neil Armstrong May 13, 2019, 9:15 a.m. UTC
On the Amlogic G12A SoC family, (only) the SDIO controller has a bug which
makes any DDR access from the MMC controller fail.

Add the amlogic,ddr-access-quirk property so signal this particular
controller has this bug and needs a quirk to work properly.

Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
---
 Documentation/devicetree/bindings/mmc/amlogic,meson-gx.txt | 4 ++++
 1 file changed, 4 insertions(+)

Comments

Martin Blumenstingl May 14, 2019, 5:50 p.m. UTC | #1
Hi Neil,

On Mon, May 13, 2019 at 11:16 AM Neil Armstrong <narmstrong@baylibre.com> wrote:
>
> On the Amlogic G12A SoC family, (only) the SDIO controller has a bug which
> makes any DDR access from the MMC controller fail.
>
> Add the amlogic,ddr-access-quirk property so signal this particular
> controller has this bug and needs a quirk to work properly.
>
> Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Reviewed-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>

> ---
>  Documentation/devicetree/bindings/mmc/amlogic,meson-gx.txt | 4 ++++
>  1 file changed, 4 insertions(+)
>
> diff --git a/Documentation/devicetree/bindings/mmc/amlogic,meson-gx.txt b/Documentation/devicetree/bindings/mmc/amlogic,meson-gx.txt
> index 13e70409e8ac..f8914dab06c6 100644
> --- a/Documentation/devicetree/bindings/mmc/amlogic,meson-gx.txt
> +++ b/Documentation/devicetree/bindings/mmc/amlogic,meson-gx.txt
> @@ -22,6 +22,10 @@ Required properties:
>    clock rate requested by the MMC core.
>  - resets     : phandle of the internal reset line
>
> +Optional properties:
> +- amlogic,ddr-access-quirk: set when HW cannot access the DDR memory, like on
> +  the G12A SDIO controller.
(I believe we cannot use a standard property like "dma-ranges" to
disable DMA access)
personally I prefer "amlogic,no-direct-memory-access" or
"amlogic,no-ddr-access", but if Rob is happy with the current naming
then I'm happy as well


Regards
Martin
Ulf Hansson May 15, 2019, 11:37 a.m. UTC | #2
On Mon, 13 May 2019 at 11:16, Neil Armstrong <narmstrong@baylibre.com> wrote:
>
> On the Amlogic G12A SoC family, (only) the SDIO controller has a bug which
> makes any DDR access from the MMC controller fail.
>
> Add the amlogic,ddr-access-quirk property so signal this particular
> controller has this bug and needs a quirk to work properly.
>
> Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
> ---
>  Documentation/devicetree/bindings/mmc/amlogic,meson-gx.txt | 4 ++++
>  1 file changed, 4 insertions(+)
>
> diff --git a/Documentation/devicetree/bindings/mmc/amlogic,meson-gx.txt b/Documentation/devicetree/bindings/mmc/amlogic,meson-gx.txt
> index 13e70409e8ac..f8914dab06c6 100644
> --- a/Documentation/devicetree/bindings/mmc/amlogic,meson-gx.txt
> +++ b/Documentation/devicetree/bindings/mmc/amlogic,meson-gx.txt
> @@ -22,6 +22,10 @@ Required properties:
>    clock rate requested by the MMC core.
>  - resets     : phandle of the internal reset line
>
> +Optional properties:
> +- amlogic,ddr-access-quirk: set when HW cannot access the DDR memory, like on
> +  the G12A SDIO controller.

As stated on the other patch, may I suggest to use DRAM instead of DDR.

Moreover, please mention that this is about the internal DMA support
of the controller.

> +
>  Example:
>
>         sd_emmc_a: mmc@70000 {
> --
> 2.21.0
>

Kind regards
Uffe
Neil Armstrong May 15, 2019, 12:43 p.m. UTC | #3
On 14/05/2019 19:50, Martin Blumenstingl wrote:
> Hi Neil,
> 
> On Mon, May 13, 2019 at 11:16 AM Neil Armstrong <narmstrong@baylibre.com> wrote:
>>
>> On the Amlogic G12A SoC family, (only) the SDIO controller has a bug which
>> makes any DDR access from the MMC controller fail.
>>
>> Add the amlogic,ddr-access-quirk property so signal this particular
>> controller has this bug and needs a quirk to work properly.
>>
>> Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
> Reviewed-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
> 
>> ---
>>  Documentation/devicetree/bindings/mmc/amlogic,meson-gx.txt | 4 ++++
>>  1 file changed, 4 insertions(+)
>>
>> diff --git a/Documentation/devicetree/bindings/mmc/amlogic,meson-gx.txt b/Documentation/devicetree/bindings/mmc/amlogic,meson-gx.txt
>> index 13e70409e8ac..f8914dab06c6 100644
>> --- a/Documentation/devicetree/bindings/mmc/amlogic,meson-gx.txt
>> +++ b/Documentation/devicetree/bindings/mmc/amlogic,meson-gx.txt
>> @@ -22,6 +22,10 @@ Required properties:
>>    clock rate requested by the MMC core.
>>  - resets     : phandle of the internal reset line
>>
>> +Optional properties:
>> +- amlogic,ddr-access-quirk: set when HW cannot access the DDR memory, like on
>> +  the G12A SDIO controller.
> (I believe we cannot use a standard property like "dma-ranges" to
> disable DMA access)
> personally I prefer "amlogic,no-direct-memory-access" or
> "amlogic,no-ddr-access", but if Rob is happy with the current naming
> then I'm happy as well

I have no preference, I can change it easily,

Neil

> 
> 
> Regards
> Martin
>
Neil Armstrong May 15, 2019, 12:43 p.m. UTC | #4
On 15/05/2019 13:37, Ulf Hansson wrote:
> On Mon, 13 May 2019 at 11:16, Neil Armstrong <narmstrong@baylibre.com> wrote:
>>
>> On the Amlogic G12A SoC family, (only) the SDIO controller has a bug which
>> makes any DDR access from the MMC controller fail.
>>
>> Add the amlogic,ddr-access-quirk property so signal this particular
>> controller has this bug and needs a quirk to work properly.
>>
>> Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
>> ---
>>  Documentation/devicetree/bindings/mmc/amlogic,meson-gx.txt | 4 ++++
>>  1 file changed, 4 insertions(+)
>>
>> diff --git a/Documentation/devicetree/bindings/mmc/amlogic,meson-gx.txt b/Documentation/devicetree/bindings/mmc/amlogic,meson-gx.txt
>> index 13e70409e8ac..f8914dab06c6 100644
>> --- a/Documentation/devicetree/bindings/mmc/amlogic,meson-gx.txt
>> +++ b/Documentation/devicetree/bindings/mmc/amlogic,meson-gx.txt
>> @@ -22,6 +22,10 @@ Required properties:
>>    clock rate requested by the MMC core.
>>  - resets     : phandle of the internal reset line
>>
>> +Optional properties:
>> +- amlogic,ddr-access-quirk: set when HW cannot access the DDR memory, like on
>> +  the G12A SDIO controller.
> 
> As stated on the other patch, may I suggest to use DRAM instead of DDR.

Indeed, may be more accurate.

> 
> Moreover, please mention that this is about the internal DMA support
> of the controller.

Ok

> 
>> +
>>  Example:
>>
>>         sd_emmc_a: mmc@70000 {
>> --
>> 2.21.0
>>
> 
> Kind regards
> Uffe
>

Patch
diff mbox series

diff --git a/Documentation/devicetree/bindings/mmc/amlogic,meson-gx.txt b/Documentation/devicetree/bindings/mmc/amlogic,meson-gx.txt
index 13e70409e8ac..f8914dab06c6 100644
--- a/Documentation/devicetree/bindings/mmc/amlogic,meson-gx.txt
+++ b/Documentation/devicetree/bindings/mmc/amlogic,meson-gx.txt
@@ -22,6 +22,10 @@  Required properties:
   clock rate requested by the MMC core.
 - resets     : phandle of the internal reset line
 
+Optional properties:
+- amlogic,ddr-access-quirk: set when HW cannot access the DDR memory, like on
+  the G12A SDIO controller.
+
 Example:
 
 	sd_emmc_a: mmc@70000 {