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Date:   Thu, 14 Sep 2023 09:35:31 +0530
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Subject: Re: [PATCH] soc: ti: k3-socinfo: Fix the silicon revision misprint
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To:     Nishanth Menon <nm@ti.com>
CC:     Thejasvi Konduru <t-konduru@ti.com>,
        <linux-kernel@vger.kernel.org>,
        <linux-arm-kernel@lists.infradead.org>,
        Santosh Shilimkar <ssantosh@kernel.org>,
        Tero Kristo <t-kristo@ti.com>,
        Grygorii Strashko <grygorii.strashko@ti.com>,
        Lokesh Vutla <lokeshvutla@ti.com>,
        Apurva Nandan <a-nandan@ti.com>, Udit Kumar <u-kumar1@ti.com>
References: <20230607080349.26671-1-t-konduru@ti.com>
 <20230607104304.iengykppptr3fxe6@reflected>
 <d50e7612-0b17-0f65-872f-90e08bed9948@ti.com>
 <20230913112823.prv5dmasvv4nt6qv@nuclear>
From:   Neha Malcom Francis <n-francis@ti.com>
In-Reply-To: <20230913112823.prv5dmasvv4nt6qv@nuclear>
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Hi Nishanth

On 13/09/23 16:58, Nishanth Menon wrote:
> On 12:07-20230912, Neha Malcom Francis wrote:
> 
> [...]
> 
>>>> +void
>>>> +k3_chipinfo_silicon_rev(unsigned int variant,
>>>> +			struct soc_device_attribute *soc_dev_attr)
>>>> +{
>>>> +	const char *family_name = soc_dev_attr->family;
>>>> +	int j721e_lookup_arr_size = ARRAY_SIZE(soc_revision_j721e);
>>>> +
>>>> +	if (!strcmp(family_name, "J721E") && variant < j721e_lookup_arr_size) {
>>>> +		soc_dev_attr->revision = kasprintf(GFP_KERNEL, "SR%s", soc_revision_j721e[variant]);
>>>> +	} else {
>>>> +		variant++;
>>>> +		soc_dev_attr->revision = kasprintf(GFP_KERNEL, "SR%x.0", variant);
>>>> +	}
>>>
>>> I am not comfortable with if else here. Why not extend k3_soc_id
>>> structure to include the variant LuT? Are there exceptions to this rule
>>> (Say AM65x?), those would make sense to handle with a compare against
>>> the partno?
>>>
>>
>> Trying to revive this patch, I see what you are saying is similar to the way
>> detection has already been implemented in U-Boot (drivers/soc/soc_ti_k3.c)
>> if I'm not mistaken.
> 
> Yes.
> 
>>
>> But I can't find any existing exception to this "family --> version" rule
>> that forces us to use "partno --> version". Checked through all AM65x device
>> TRMs available in ti.com; all seem to use common partno. So maybe I am not
>> on the same page, did you mean something else?
> 
> https://www.ti.com/lit/ug/spruid7e/spruid7e.pdf
> CTRLMMR_WKUP_JTAGID:: VARIANT field: SR2.0: 1h SR1.0: 0h
> Latest data sheet: https://www.ti.com/lit/ds/symlink/am6548.pdf
> indicates SR 2.1
> 
> How is this detected?

Detection of the ".x" bit is still a WIP and needs some alignment internally 
before I can add that patch. So for now, working on cleaning up the known issues 
of the driver.

> 
> What I indicated is a LUT table similar to
> https://git.ti.com/cgit/k3conf/k3conf/tree/common/socinfo.c#n382
> 
> This allows a switch statement to handle custom SR handling schemes or
> use LUT with variants that use VARIANT field to handle things properly.
> 

This makes sense, will work on the patch accordingly. Thanks!

> [...]

-- 
Thanking You
Neha Malcom Francis