[PATCH v3 1/3] dt-bindings: net: Add T-HEAD dwmac support
Krzysztof Kozlowski
krzk at kernel.org
Thu Oct 3 03:42:09 PDT 2024
On 02/10/2024 21:08, Drew Fustini wrote:
> On Tue, Oct 01, 2024 at 08:58:34AM +0200, Krzysztof Kozlowski wrote:
>> On Mon, Sep 30, 2024 at 11:23:24PM -0700, Drew Fustini wrote:
>>> From: Jisheng Zhang <jszhang at kernel.org>
>>>
>>> Add documentation to describe the DesginWare-based GMAC controllers in
>>> the T-HEAD TH1520 SoC.
>>>
>>> Signed-off-by: Jisheng Zhang <jszhang at kernel.org>
>>> Signed-off-by: Emil Renner Berthing <emil.renner.berthing at canonical.com>
>>> [drew: rename compatible, add apb registers as second reg of gmac node]
>>> Signed-off-by: Drew Fustini <dfustini at tenstorrent.com>
>>> ---
>>> .../devicetree/bindings/net/snps,dwmac.yaml | 1 +
>>> .../devicetree/bindings/net/thead,th1520-gmac.yaml | 97 ++++++++++++++++++++++
>>> MAINTAINERS | 1 +
>>> 3 files changed, 99 insertions(+)
>>>
>>> diff --git a/Documentation/devicetree/bindings/net/snps,dwmac.yaml b/Documentation/devicetree/bindings/net/snps,dwmac.yaml
>>> index 4e2ba1bf788c..474ade185033 100644
>>> --- a/Documentation/devicetree/bindings/net/snps,dwmac.yaml
>>> +++ b/Documentation/devicetree/bindings/net/snps,dwmac.yaml
>>> @@ -99,6 +99,7 @@ properties:
>>> - snps,dwxgmac-2.10
>>> - starfive,jh7100-dwmac
>>> - starfive,jh7110-dwmac
>>> + - thead,th1520-gmac
>>>
>>> reg:
>>> minItems: 1
>>> diff --git a/Documentation/devicetree/bindings/net/thead,th1520-gmac.yaml b/Documentation/devicetree/bindings/net/thead,th1520-gmac.yaml
>>> new file mode 100644
>>> index 000000000000..fef1810b10c4
>>> --- /dev/null
>>> +++ b/Documentation/devicetree/bindings/net/thead,th1520-gmac.yaml
>>> @@ -0,0 +1,97 @@
>>> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
>>> +%YAML 1.2
>>> +---
>>> +$id: http://devicetree.org/schemas/net/thead,th1520-gmac.yaml#
>>> +$schema: http://devicetree.org/meta-schemas/core.yaml#
>>> +
>>> +title: T-HEAD TH1520 GMAC Ethernet controller
>>> +
>>> +maintainers:
>>> + - Drew Fustini <dfustini at tenstorrent.com>
>>> +
>>> +description: |
>>> + The TH1520 GMAC is described in the TH1520 Peripheral Interface User Manual
>>> + https://git.beagleboard.org/beaglev-ahead/beaglev-ahead/-/tree/main/docs
>>> +
>>> + Features include
>>> + - Compliant with IEEE802.3 Specification
>>> + - IEEE 1588-2008 standard for precision networked clock synchronization
>>> + - Supports 10/100/1000Mbps data transfer rate
>>> + - Supports RGMII/MII interface
>>> + - Preamble and start of frame data (SFD) insertion in Transmit path
>>> + - Preamble and SFD deletion in the Receive path
>>> + - Automatic CRC and pad generation options for receive frames
>>> + - MDIO master interface for PHY device configuration and management
>>> +
>>> + The GMAC Registers consists of two parts
>>> + - APB registers are used to configure clock frequency/clock enable/clock
>>> + direction/PHY interface type.
>>> + - AHB registers are use to configure GMAC core (DesignWare Core part).
>>> + GMAC core register consists of DMA registers and GMAC registers.
>>> +
>>> +select:
>>> + properties:
>>> + compatible:
>>> + contains:
>>> + enum:
>>> + - thead,th1520-gmac
>>> + required:
>>> + - compatible
>>> +
>>> +allOf:
>>> + - $ref: snps,dwmac.yaml#
>>> +
>>> +properties:
>>> + compatible:
>>> + items:
>>> + - enum:
>>> + - thead,th1520-gmac
>>> + - const: snps,dwmac-3.70a
>>> +
>>> + reg:
>>> + items:
>>> + - description: DesignWare GMAC IP core registers
>>> + - description: GMAC APB registers
>>> +
>>> + reg-names:
>>> + items:
>>> + - const: dwmac
>>> + - const: apb
>>
>> I don't get why none of snps,dwmac properties are restricted. How many
>> interrupts do you have here? How many clocks? resets?
>
> Thanks for pointing this out. Yes, I forgot to document the clocks,
> interrupts and resets.
>
> There needs to be 2 clocks (stmmaceth and pclk). There also needs to be
> 2 resets: each GMAC has a reset plus a seperate reset for the GMAC AXI
> interface. There is 1 interrupt (macirq) but it is optional. The BeagleV
> Ahead uses it but the LicheePi 4A does not use the interrupt.
>
> However, I'm uncertain about how to restrict the snps,dwmac properties.
>
> I see that starfive,jh7110-dwmac.yaml has the following logic. Should I
> be adding something like this to restrict the snps,dwmac properties?
>
> ---------------------------------------------------------------------
> allOf:
> - $ref: snps,dwmac.yaml#
>
> - if:
> properties:
> compatible:
> contains:
> const: starfive,jh7100-dwmac
> then:
> properties:
> interrupts:
> minItems: 2
> maxItems: 2
>
> interrupt-names:
> minItems: 2
> maxItems: 2
>
> resets:
> maxItems: 1
>
> reset-names:
> const: ahb
No, that's not necessary. You have one device in this binding, so in
top-level should define how each such property looks like.
Best regards,
Krzysztof
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