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SubjectRE: [PATCH v4 4/5] net: macb: add support for high speed interface
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Hi Andrew,

>> +enum {
>> + MACB_SERDES_RATE_5_PT_15625Gbps = 5,
>> + MACB_SERDES_RATE_10_PT_3125Gbps = 10,
>> +};
>What do the units mean here? Why would you clock the SERDES at 15Tbps,
>or 3Tbps? 3.125Mbps would give you 2.5Gbps when using 8b/10b encoding.
>
MACB_SERDES_RATE_5_PT_15625Gbps is for 5.15625Gbps, I think this should be just
MACB_SERDES_RATE_5_Gbps and MACB_SERDES_RATE_10_Gbps. I will do it in next patch set.

>Xilinx documentation:
>https://urldefense.proofpoint.com/v2/url?u=https-
>3A__www.xilinx.com_support_documentation_ip-5Fdocumentation_usxgmii_v1-
>5F1_pg251-
>2Dusxgmii.pdf&d=DwIBAg&c=aUq983L2pue2FqKFoP6PGHMJQyoJ7kl3s3GZ-
>_haXqY&r=GTefrem3hiBCnsjCOqAuapQHRN8-rKC1FRbk0it-
>LDs&m=6V8fNIg49czRjfvVtDJ5BbR28p9UPlLLyB7fah7ypcw&s=LsDphgLBe1VDpM
>_K9pkuyal873WeKqHDv64NDRUWy1Q&e=
>seems to suggest USXGMII uses a fixed rate of 10.3125Gb/s. So why do
>you need to change the rate?
For USXGMII, Cadence MAC need to be correctly programmed for external serdes rate.

Regards,
Parshuram Thombare

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