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Message-ID: <d030a431-933d-4f54-ba6a-f7bc5a12f843@ti.com>
Date:   Sat, 27 May 2023 12:01:28 +0530
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Subject: Re: [PATCH] arm64: dts: ti: k3-am62-main: Remove power-domains from
 crypto node
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To:     Francesco Dolcini <francesco@dolcini.it>,
        Nishanth Menon <nm@ti.com>, <kamlesh@ti.com>
CC:     <kristo@kernel.org>, <robh+dt@kernel.org>,
        <krzysztof.kozlowski+dt@linaro.org>,
        <linux-arm-kernel@lists.infradead.org>,
        <devicetree@vger.kernel.org>, <linux-kernel@vger.kernel.org>
References: <20230417133308.1990057-1-kamlesh@ti.com>
 <20230417134241.oj5cmrqjeoxj2sb2@power>
 <ZG90RS4KYo0bCwF7@francesco-nb.int.toradex.com>
From:   Vignesh Raghavendra <vigneshr@ti.com>
In-Reply-To: <ZG90RS4KYo0bCwF7@francesco-nb.int.toradex.com>
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On 25/05/23 8:14 pm, Francesco Dolcini wrote:
> On Mon, Apr 17, 2023 at 08:42:41AM -0500, Nishanth Menon wrote:
>> On 19:03-20230417, kamlesh@ti.com wrote:
>>> From: Kamlesh Gurudasani <kamlesh@ti.com>
>>>
>>> With latest firmware update, we can no longer control power of SA3UL from
>>> main domain.
>>
>> How is this backward compatible?
> 
> I just stumbled across this commit since I had an issue with crypto@40900000
> not being probed on Verdin AM62.
> 
> Not sure how this is supposed to work about backward/forward
> compatibility, however this is needed for having it working with the
> latest firmware.
> 

From what I understand, newer firmware seems to hate SA3UL PD control
requests. But older firmwares just ignored the call as the SA3UL PD is
on by default. So as such, this DT patch alone wont break
forward/backward compatibility.

It looks like newer firmware is broken wrt older kernel which is
unfortunate.

Kamlesh: can you resubmit this patch with appropriate "Fixes" tag so
that it gets backported to stable kernels?

> And if there is a proper way that take care of this, it should be
> backported IMO.
> 
> Francesco
>