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[v3,2/4] dt-bindings: memory: tegra20: emc: Document new LPDDR2 sub-node

Message ID 20211003013235.2357-3-digetx@gmail.com
State Superseded, archived
Headers show
Series tegra20-emc: Identify memory chip by LPDDR configuration | expand

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Commit Message

Dmitry Osipenko Oct. 3, 2021, 1:32 a.m. UTC
Some Tegra20 boards don't have RAM code stored in NVMEM, which is used for
the memory chip identification and the identity information should be read
out from LPDDR2 chip in this case. Document new sub-node containing generic
LPDDR2 properties that will be used for the memory chip identification if
RAM code isn't available. The identification is done by reading out memory
configuration values from generic LPDDR2 mode registers of SDRAM chip and
comparing them with the values of device-tree sub-node's.

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 .../memory-controllers/nvidia,tegra20-emc.yaml  | 17 ++++++++++++++---
 1 file changed, 14 insertions(+), 3 deletions(-)

Comments

Krzysztof Kozlowski Oct. 4, 2021, 8:37 a.m. UTC | #1
On 03/10/2021 03:32, Dmitry Osipenko wrote:
> Some Tegra20 boards don't have RAM code stored in NVMEM, which is used for
> the memory chip identification and the identity information should be read
> out from LPDDR2 chip in this case. Document new sub-node containing generic
> LPDDR2 properties that will be used for the memory chip identification if
> RAM code isn't available. The identification is done by reading out memory
> configuration values from generic LPDDR2 mode registers of SDRAM chip and
> comparing them with the values of device-tree sub-node's.
> 
> Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
> ---
>  .../memory-controllers/nvidia,tegra20-emc.yaml  | 17 ++++++++++++++---
>  1 file changed, 14 insertions(+), 3 deletions(-)
> 
> diff --git a/Documentation/devicetree/bindings/memory-controllers/nvidia,tegra20-emc.yaml b/Documentation/devicetree/bindings/memory-controllers/nvidia,tegra20-emc.yaml
> index cac6842dc8f1..65f7c3898ac4 100644
> --- a/Documentation/devicetree/bindings/memory-controllers/nvidia,tegra20-emc.yaml
> +++ b/Documentation/devicetree/bindings/memory-controllers/nvidia,tegra20-emc.yaml
> @@ -164,13 +164,14 @@ patternProperties:
>        "#size-cells":
>          const: 0
>  
> +      lpddr2-configuration:

Nodes should be named generic, so just lpddr2?


> +        $ref: "jedec,lpddr2.yaml#"
> +        type: object
> +
>      patternProperties:
>        "^emc-table@[0-9]+$":
>          $ref: "#/$defs/emc-table"
>  
> -    required:
> -      - nvidia,ram-code

Isn't lpddr2-configuration required in such case? If not, probably you
want either this or that (oneOf like in reserved-memory.yaml).

> -
>      additionalProperties: false
>  
>  required:
> @@ -186,6 +187,8 @@ additionalProperties: false
>  
>  examples:
>    - |
> +    #include <dt-bindings/memory/lpddr2.h>
> +
>      external-memory-controller@7000f400 {
>          compatible = "nvidia,tegra20-emc";
>          reg = <0x7000f400 0x400>;
> @@ -226,5 +229,13 @@ examples:
>                          0x007fe010 0x00001414 0x00000000 0x00000000
>                          0x00000000 0x00000000 0x00000000 0x00000000>;
>              };
> +
> +            lpddr2-configuration {
> +                jedec,lpddr2-manufacturer-id = <LPDDR2_MANID_ELPIDA>;
> +                jedec,lpddr2-revision-id1 = <1>;
> +                jedec,lpddr2-density-mbits = <2048>;
> +                jedec,lpddr2-io-width-bits = <16>;
> +                jedec,lpddr2-type = <LPDDR2_TYPE_S4>;
> +            };
>          };
>      };
> 


Best regards,
Krzysztof
Dmitry Osipenko Oct. 4, 2021, 4:56 p.m. UTC | #2
04.10.2021 11:37, Krzysztof Kozlowski пишет:
> On 03/10/2021 03:32, Dmitry Osipenko wrote:
>> Some Tegra20 boards don't have RAM code stored in NVMEM, which is used for
>> the memory chip identification and the identity information should be read
>> out from LPDDR2 chip in this case. Document new sub-node containing generic
>> LPDDR2 properties that will be used for the memory chip identification if
>> RAM code isn't available. The identification is done by reading out memory
>> configuration values from generic LPDDR2 mode registers of SDRAM chip and
>> comparing them with the values of device-tree sub-node's.
>>
>> Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
>> ---
>>  .../memory-controllers/nvidia,tegra20-emc.yaml  | 17 ++++++++++++++---
>>  1 file changed, 14 insertions(+), 3 deletions(-)
>>
>> diff --git a/Documentation/devicetree/bindings/memory-controllers/nvidia,tegra20-emc.yaml b/Documentation/devicetree/bindings/memory-controllers/nvidia,tegra20-emc.yaml
>> index cac6842dc8f1..65f7c3898ac4 100644
>> --- a/Documentation/devicetree/bindings/memory-controllers/nvidia,tegra20-emc.yaml
>> +++ b/Documentation/devicetree/bindings/memory-controllers/nvidia,tegra20-emc.yaml
>> @@ -164,13 +164,14 @@ patternProperties:
>>        "#size-cells":
>>          const: 0
>>  
>> +      lpddr2-configuration:
> 
> Nodes should be named generic, so just lpddr2?

Yes

>> +        $ref: "jedec,lpddr2.yaml#"
>> +        type: object
>> +
>>      patternProperties:
>>        "^emc-table@[0-9]+$":
>>          $ref: "#/$defs/emc-table"
>>  
>> -    required:
>> -      - nvidia,ram-code
> 
> Isn't lpddr2-configuration required in such case? If not, probably you
> want either this or that (oneOf like in reserved-memory.yaml).

Thanks, oneOf will work.
diff mbox series

Patch

diff --git a/Documentation/devicetree/bindings/memory-controllers/nvidia,tegra20-emc.yaml b/Documentation/devicetree/bindings/memory-controllers/nvidia,tegra20-emc.yaml
index cac6842dc8f1..65f7c3898ac4 100644
--- a/Documentation/devicetree/bindings/memory-controllers/nvidia,tegra20-emc.yaml
+++ b/Documentation/devicetree/bindings/memory-controllers/nvidia,tegra20-emc.yaml
@@ -164,13 +164,14 @@  patternProperties:
       "#size-cells":
         const: 0
 
+      lpddr2-configuration:
+        $ref: "jedec,lpddr2.yaml#"
+        type: object
+
     patternProperties:
       "^emc-table@[0-9]+$":
         $ref: "#/$defs/emc-table"
 
-    required:
-      - nvidia,ram-code
-
     additionalProperties: false
 
 required:
@@ -186,6 +187,8 @@  additionalProperties: false
 
 examples:
   - |
+    #include <dt-bindings/memory/lpddr2.h>
+
     external-memory-controller@7000f400 {
         compatible = "nvidia,tegra20-emc";
         reg = <0x7000f400 0x400>;
@@ -226,5 +229,13 @@  examples:
                         0x007fe010 0x00001414 0x00000000 0x00000000
                         0x00000000 0x00000000 0x00000000 0x00000000>;
             };
+
+            lpddr2-configuration {
+                jedec,lpddr2-manufacturer-id = <LPDDR2_MANID_ELPIDA>;
+                jedec,lpddr2-revision-id1 = <1>;
+                jedec,lpddr2-density-mbits = <2048>;
+                jedec,lpddr2-io-width-bits = <16>;
+                jedec,lpddr2-type = <LPDDR2_TYPE_S4>;
+            };
         };
     };