Re: 回覆: 回覆: [PATCH v2 05/10] ARM: dts: aspeed: system1: Add RGMII support

[Ninad Palsule <ninad@linux.ibm.com>]

Hi Jacky,

On 1/10/25 03:15, Jacky Chou wrote:
> Hi Andrew,
>
> Thank you for your reply.
>
>>> I think the code already exist in the mainline:
>>> https://github.com/torvalds/linux/blob/master/drivers/clk/clk-ast2600.
>>> c#L595
>>>
>>> It is configuring SCU register in the ast2600 SOC to introduce delays.
>>> The mac is part of the SOC.
>> I could be reading this wrong, but that appears to create a gated clock.
>>
>> hw = clk_hw_register_gate(dev, "mac1rclk", "mac12rclk", 0,
>> 	       		scu_g6_base + ASPEED_MAC12_CLK_DLY, 29, 0,
>> 			&aspeed_g6_clk_lock);
>>
>> /**
>>   * clk_hw_register_gate - register a gate clock with the clock framework
>>   * @dev: device that is registering this clock
>>   * @name: name of this clock
>>   * @parent_name: name of this clock's parent
>>   * @flags: framework-specific flags for this clock
>>   * @reg: register address to control gating of this clock
>>   * @bit_idx: which bit in the register controls gating of this clock
>>   * @clk_gate_flags: gate-specific flags for this clock
>>   * @lock: shared register lock for this clock  */
>>
>> There is nothing here about writing a value into @reg at creation time to give
>> it a default value. If you look at the vendor code, it has extra writes, but i don't
>> see anything like that in mainline.
> Agree. You are right. This part is used to create a gated clock.
> We will configure these RGMII delay in bootloader like U-boot.
> Therefore, here does not configure delay again.
>
> Currently, the delay of RGMII is configured in SCU region not in ftgma100 region.
> And I studied ethernet-controller.yaml file, as you said, it has defined about rgmii
> delay property for MAC side to set.
> My plan is that I will move this delay setting to ftgmac100 driver from SCU.
> Add a SCU syscon property for ftgmac100 driver configures the RGMII delay.
>
> // aspeed-g6.dtsi
> mac0: ethernet@1e660000 {
> 			compatible = "aspeed,ast2600-mac", "faraday,ftgmac100";
> 			reg = <0x1e660000 0x180>;
> 			interrupts = <GIC_SPI 2 IRQ_TYPE_LEVEL_HIGH>;
> 			clocks = <&syscon ASPEED_CLK_GATE_MAC1CLK>;
> 			aspeed,scu = <&syscon>;    ------> add
> 			status = "disabled";
> 		};
>
> Because AST2600 MAC1/2 RGMII delay setting in scu region is combined to one 32-bit register,
> MAC3/4 is also. I will also use 'aliase' to get MAC index to set delay in scu.
>
> // aspeed-g6.dtsi
> aliases {
> 		..........
> 		mac0 = &mac0;
> 		mac1 = &mac1;
> 		mac2 = &mac2;
> 		mac4 = &mac3;
> 	};
>
> Then, we can use rx-internal-delay-ps and tx-internal-delay-ps property to configure delay
> In ftgmac100 driver.

Thanks. When are you planning to push this change? I might need to hold 
on to mac changes until then.

Regards,

Ninad

>
> If you have any questions, please let me know. Thank you.
>
> Thanks,
> Jacky