linux-kernel - Re: [PATCH v4 7/7] irqchip: qcom-pdc: Reset all pdc interrupts during init

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Message-ID: <1272cba3-1a6c-4d2e-0b4b-a19dfb5f3a4d@codeaurora.org>
Date:   Thu, 13 Aug 2020 13:00:44 +0530
From:   Maulik Shah <mkshah@...eaurora.org>
To:     Stephen Boyd <swboyd@...omium.org>, bjorn.andersson@...aro.org,
        evgreen@...omium.org, linus.walleij@...aro.org, maz@...nel.org,
        mka@...omium.org
Cc:     linux-kernel@...r.kernel.org, linux-arm-msm@...r.kernel.org,
        linux-gpio@...r.kernel.org, agross@...nel.org, tglx@...utronix.de,
        jason@...edaemon.net, dianders@...omium.org, rnayak@...eaurora.org,
        ilina@...eaurora.org, lsrao@...eaurora.org
Subject: Re: [PATCH v4 7/7] irqchip: qcom-pdc: Reset all pdc interrupts during
 init

Hi,

On 8/12/2020 3:01 AM, Stephen Boyd wrote:
> Quoting Maulik Shah (2020-08-10 04:21:00)
>> Clear previous kernel's configuration during init by resetting
>> interrupts in enable bank to zero.
> Can you please add some more information here about why we're not
> clearing all the pdc irqs and only the ones that are listed in DT?
sure.
>   Is
> that because the pdc is shared between exception levels of the CPU and
> so some irqs shouldn't be used? Does the DT binding need to change to
> only list the hwirqs that are usable by the OS instead of the ones that
> are usable for the entire system? The binding doesn't mention this at
> all so I am just guessing here.

The IRQs specified in qcom,pdc-ranges property in DT are the only ones 
that can be used in the current OS for the PDC.

So instead of setting entire register to zero (each reg supports 32 
interrupts enable bit) only clearing the ones that can be used.

Thanks,
Maulik

>
>> Suggested-by: Stephen Boyd <swboyd@...omium.org>
>> Signed-off-by: Maulik Shah <mkshah@...eaurora.org>

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