Re: [PATCH 05/12] dt-bindings: mtd: brcmnand: Updates for bcmbca SoCs

William Zhang
2023-06-07T20:02:09Z

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Hi Miquel,

On 06/07/2023 01:14 AM, Miquel Raynal wrote:
> Hi William,
>
> william.zhang@broadcom.com wrote on Tue, 6 Jun 2023 16:12:45 -0700:
>
>> Use new compatiable brcm,nand-bcmbca to support BCMBCA broadband
>> product. The old compatible string is still kept in the driver so old
>> dtb can still work.
>>
>> Add brcm,nand-use-wp property to have an option for disabling this
>> feature on broadband board design that does not use write protection.
>> Add brcm,nand-ecc-use-strap to get ecc setting from board strap for
>> broadband board designs because they do not specify ecc setting in dts
>> but rather using the strap setting.
>>
>> Remove the requirement of interrupts and interrupt-names properties to
>> reflect the driver code.
>>
>> This patch also includes a few minor fixes to the BCM63xx compatibles
>> and add myself to the list of maintainers.
>>
>> Signed-off-by: William Zhang <william.zhang@broadcom.com>
>> ---
>>
>> .../bindings/mtd/brcm,brcmnand.yaml | 64 +++++++++++++------
>> 1 file changed, 43 insertions(+), 21 deletions(-)
>>
>> diff --git a/Documentation/devicetree/bindings/mtd/brcm,brcmnand.yaml b/Documentation/devicetree/bindings/mtd/brcm,brcmnand.yaml
>> index 1571024aa119..1fe1c166a9db 100644
>> --- a/Documentation/devicetree/bindings/mtd/brcm,brcmnand.yaml
>> +++ b/Documentation/devicetree/bindings/mtd/brcm,brcmnand.yaml
>> @@ -9,6 +9,7 @@ title: Broadcom STB NAND Controller
>> maintainers:
>> - Brian Norris <computersforpeace@gmail.com>
>> - Kamal Dasu <kdasu.kdev@gmail.com>
>> + - William Zhang <william.zhang@broadcom.com>
>>
>> description: |
>> The Broadcom Set-Top Box NAND controller supports low-level access to raw NAND
>> @@ -18,9 +19,10 @@ description: |
>> supports basic PROGRAM and READ functions, among other features.
>>
>> This controller was originally designed for STB SoCs (BCM7xxx) but is now
>> - available on a variety of Broadcom SoCs, including some BCM3xxx, BCM63xx, and
>> - iProc/Cygnus. Its history includes several similar (but not fully register
>> - compatible) versions.
>> + available on a variety of Broadcom SoCs, including some BCM3xxx, MIPS based
>> + Broadband SoC (BCM63xx), ARM based Broadband SoC (BCMBCA) and iProc/Cygnus.
>> + Its history includes several similar (but not fully register compatible)
>> + versions.
>>
>> -- Additional SoC-specific NAND controller properties --
>>
>> @@ -53,9 +55,9 @@ properties:
>> - brcm,brcmnand-v7.2
>> - brcm,brcmnand-v7.3
>> - const: brcm,brcmnand
>> - - description: BCM63138 SoC-specific NAND controller
>> + - description: BCMBCA SoC-specific NAND controller
>> items:
>> - - const: brcm,nand-bcm63138
>> + - const: brcm,nand-bcmbca
>> - enum:
>> - brcm,brcmnand-v7.0
>> - brcm,brcmnand-v7.1
>> @@ -65,11 +67,15 @@ properties:
>> - const: brcm,nand-iproc
>> - const: brcm,brcmnand-v6.1
>> - const: brcm,brcmnand
>> - - description: BCM63168 SoC-specific NAND controller
>> + - description: BCM63xx SoC-specific NAND controller
>> items:
>> - - const: brcm,nand-bcm63168
>> - - const: brcm,nand-bcm6368
>> - - const: brcm,brcmnand-v4.0
>> + - enum:
>> + - brcm,nand-bcm63168
>> + - brcm,nand-bcm6368
>> + - enum:
>> + - brcm,brcmnand-v2.1
>> + - brcm,brcmnand-v2.2
>> + - brcm,brcmnand-v4.0
>> - const: brcm,brcmnand
>>
>> reg:
>> @@ -111,6 +117,19 @@ properties:
>> earlier versions of this core that include WP
>> type: boolean
>>
>> + brcm,nand-use-wp:
>> + description:
>> + Use this integer to indicate if board design uses
>> + controller's write protection feature and connects its
>> + NAND_WPb pin to nand chip's WP_L pin. Driver defaults to
>> + use this feature when this property does not exist.
>> + Set to 0 if WP pins are not connected and feature is not
>> + used. Set to 1 if WP pins are connected and feature is used.
>> + Set to 2 if WP pins are connected but disable this feature
>> + through driver that sets controller to output high on NAND_WPb.
>> + $ref: /schemas/types.yaml#/definitions/uint32
>> + enum: [0, 1, 2]
>
> Perhaps strings would be welcome. I'll let binding maintainers say what
> they think of it.
>
Practically there is really just use cases of 0 and 1. I could use a
bool flag but to keep consistent with the driver code and in case there
is any existing usage of 2.

>> +
>> patternProperties:
>> "^nand@[a-f0-9]$":
>> type: object
>> @@ -136,13 +155,23 @@ patternProperties:
>> layout.
>> $ref: /schemas/types.yaml#/definitions/uint32
>>
>> + brcm,nand-ecc-use-strap:
>> + description:
>> + This flag is used by the driver to get the ecc strength and
>> + spare area size from the SoC NAND boot strap setting. This
>> + is commonly used by the BCMBCA SoC board design. If ecc
>> + strength and spare area size are set by nand-ecc-strength
>> + and brcm,nand-oob-sector-size in the dts, these settings
>> + have precedence and override this flag.
>> + $ref: /schemas/types.yaml#/definitions/flag
>
> How in practice do you access the strap value? Don't you need a phandle
> over a specific area in the SoC?
>
The strap value is latched and stored in the NAND controller register so
there is no extra phandle needed.

>> +
>> allOf:
>> - $ref: nand-controller.yaml#
>> - if:
>> properties:
>> compatible:
>> contains:
>> - const: brcm,nand-bcm63138
>> + const: brcm,nand-bcmbca
>> then:
>> properties:
>> reg-names:
>> @@ -153,7 +182,9 @@ allOf:
>> properties:
>> compatible:
>> contains:
>> - const: brcm,nand-bcm6368
>> + enum:
>> + - brcm,nand-bcm63168
>> + - brcm,nand-bcm6368
>> then:
>> properties:
>> reg-names:
>> @@ -173,20 +204,12 @@ allOf:
>> - const: nand
>> - const: iproc-idm
>> - const: iproc-ext
>> - - if:
>> - properties:
>> - interrupts:
>> - minItems: 2
>> - then:
>> - required:
>> - - interrupt-names
>
> Why do you remove this? Removing "interrupts" from the required
> properties is fine, but constraining the interrupts property when it is
> relevant is still expected.
>
There is no requirement for interrupt name even if it have two
interrupts. Driver code does not use interrupt name but the interrupt
index instead.

>>
>> unevaluatedProperties: false
>>
>> required:
>> - reg
>> - reg-names
>> - - interrupts
>
> This should be done in a separate patch.
>
I thought this is also related to my update for bcmbca chips because
they don't need to interrupt and interrupt name.

>>
>> examples:
>> - |
>> @@ -215,8 +238,7 @@ examples:
>> };
>> - |
>> nand-controller@10000200 {
>> - compatible = "brcm,nand-bcm63168", "brcm,nand-bcm6368",
>> - "brcm,brcmnand-v4.0", "brcm,brcmnand";
>> + compatible = "brcm,nand-bcm6368", "brcm,brcmnand-v2.1", "brcm,brcmnand";
>> reg = <0x10000200 0x180>,
>> <0x100000b0 0x10>,
>> <0x10000600 0x200>;
>
>
> Thanks,
> Miquèl