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Message-ID: <2046f9ad-b5c2-bc42-03de-6254d6ed92d3@ti.com>
Date:   Fri, 20 Oct 2023 23:35:34 +0530
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Subject: Re: [PATCH net-next v2] net: ethernet: ti: davinci_mdio: Update K3
 SoCs list for errata i2329
To:     Nishanth Menon <nm@ti.com>
CC:     <kuba@kernel.org>, <davem@davemloft.net>, <edumazet@google.com>,
        <pabeni@redhat.com>, <rogerq@kernel.org>, <andrew@lunn.ch>,
        <f.fainelli@gmail.com>, <horms@kernel.org>,
        <linux-omap@vger.kernel.org>, <netdev@vger.kernel.org>,
        <linux-kernel@vger.kernel.org>, <srk@ti.com>,
        <linux-arm-kernel@lists.infradead.org>,
        Ravi Gunasekaran <r-gunasekaran@ti.com>
References: <20231020111738.14671-1-r-gunasekaran@ti.com>
 <20231020122359.vwia7sxrcjyeo3ov@pushover>
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From:   Ravi Gunasekaran <r-gunasekaran@ti.com>
In-Reply-To: <20231020122359.vwia7sxrcjyeo3ov@pushover>
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On 10/20/2023 5:53 PM, Nishanth Menon wrote:
> On 16:47-20231020, Ravi Gunasekaran wrote:
>> The errata i2329 affects certain K3 SoC versions. The k3-socinfo.c
>> driver generates the revision string for different variants of the
>> same SoC in an incremental fashion. This is not true for all SoCs.
>> An example case being J721E, for which the actual silicon revision
>> names are 1.0, 1.1 for its variants, while the k3-socinfo.c driver
>> interprets these variants as revisions 1.0, 2.0 respectively,
>> which is incorrect.
>>
>> While the work to fixup the silicon revision string is posted
>> to the soc tree, this patch serves as a fail-safe step by maintaining
>> a list of correct and incorrect revision strings, so that the fixup
>> work does not break the errata workaround for such corrected SoCs.
>>
>> The silicon revisions affected by the errata i2329 can be found under
>> the MDIO module in the "Advisories by Modules" section of each
>> SoC errata document listed below
>>
>> AM62x: https://www.ti.com/lit/er/sprz487c/sprz487c.pdf
>> AM64X: https://www.ti.com/lit/er/sprz457g/sprz457g.pdf
>> AM65X: https://www.ti.com/lit/er/sprz452i/sprz452i.pdf
>> J7200: https://www.ti.com/lit/er/sprz491d/sprz491d.pdf
>> J721E: https://www.ti.com/lit/er/sprz455d/sprz455d.pdf
>> J721S2: https://www.ti.com/lit/er/sprz530b/sprz530b.pdf
>>
>> Signed-off-by: Ravi Gunasekaran <r-gunasekaran@ti.com>
>> ---
>>
>> Changes since v1:
>> * For J721E, retained the incorrect SR ID and added the correct one
>> * Add AM65x SR2.1 to the workaround list
>>
>> v1: https://lore.kernel.org/all/20231018140009.1725-1-r-gunasekaran@ti.com/
>>
>>  drivers/net/ethernet/ti/davinci_mdio.c | 2 ++
>>  1 file changed, 2 insertions(+)
>>
>> diff --git a/drivers/net/ethernet/ti/davinci_mdio.c b/drivers/net/ethernet/ti/davinci_mdio.c
>> index 628c87dc1d28..25aaef502edc 100644
>> --- a/drivers/net/ethernet/ti/davinci_mdio.c
>> +++ b/drivers/net/ethernet/ti/davinci_mdio.c
>> @@ -516,9 +516,11 @@ static const struct soc_device_attribute k3_mdio_socinfo[] = {
>>  	{ .family = "AM64X", .revision = "SR2.0", .data = &am65_mdio_soc_data },
>>  	{ .family = "AM65X", .revision = "SR1.0", .data = &am65_mdio_soc_data },
>>  	{ .family = "AM65X", .revision = "SR2.0", .data = &am65_mdio_soc_data },
>> +	{ .family = "AM65X", .revision = "SR2.1", .data = &am65_mdio_soc_data },
>>  	{ .family = "J7200", .revision = "SR1.0", .data = &am65_mdio_soc_data },
>>  	{ .family = "J7200", .revision = "SR2.0", .data = &am65_mdio_soc_data },
>>  	{ .family = "J721E", .revision = "SR1.0", .data = &am65_mdio_soc_data },
>> +	{ .family = "J721E", .revision = "SR1.1", .data = &am65_mdio_soc_data },
>>  	{ .family = "J721E", .revision = "SR2.0", .data = &am65_mdio_soc_data },
>>  	{ .family = "J721S2", .revision = "SR1.0", .data = &am65_mdio_soc_data},
>>  	{ /* sentinel */ },
>>
> Looks like every device is impacted -> so, why not just flip the
> logic to indicate devices that are NOT impacted? is'nt that a smaller
> list?
>

At the moment, the list of unaffected devices is small. But as and when we
introduce more devices,
this list will need update. Also I feel that few years down the line, when
someone looks at the code,
a list of affected devices provides a better context as it is easier to trace it
back to the errata document.

Regards,
Ravi