linux-kernel - Re: [PATCH 2/2] rtc: imxdi: use the security violation interrupt

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Message-ID: <20161207154716.5pkdctgnjhnuqp53@piout.net>
Date:   Wed, 7 Dec 2016 16:47:16 +0100
From:   Alexandre Belloni <alexandre.belloni@...e-electrons.com>
To:     Martin Kaiser <martin@...ser.cx>
Cc:     Shawn Guo <shawnguo@...nel.org>,
        Sascha Hauer <kernel@...gutronix.de>,
        Juergen Borleis <jbe@...gutronix.de>,
        Rob Herring <robh+dt@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Fabio Estevam <fabio.estevam@....com>,
        rtc-linux@...glegroups.com, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 2/2] rtc: imxdi: use the security violation interrupt

Hi,

On 19/11/2016 at 14:03:34 +0100, Martin Kaiser wrote :
> The DryIce chipset has a dedicated security violation interrupt that is
> triggered for security violations (if configured to do so). According to
> the publicly available imx258 reference manual, irq 56 is used for this
> interrupt.
> 
> Install a handler for the security violation interrupt. Move the code
> for handling security violations from the "normal" interrupt handler
> into the security violation interrupt handler.
> 
> Signed-off-by: Martin Kaiser <martin@...ser.cx>
> ---
>  .../devicetree/bindings/rtc/imxdi-rtc.txt          |    4 +-
>  arch/arm/boot/dts/imx25.dtsi                       |    2 +-

This change should be in a separate patch.

> @@ -783,6 +801,9 @@ static int __init dryice_rtc_probe(struct platform_device *pdev)
>  	imxdi->irq = platform_get_irq(pdev, 0);
>  	if (imxdi->irq < 0)
>  		return imxdi->irq;
> +	imxdi->sec_irq = platform_get_irq(pdev, 1);
> +	if (imxdi->sec_irq < 0)
> +		return imxdi->sec_irq;
>  
>  	init_waitqueue_head(&imxdi->write_wait);
>  
> @@ -815,6 +836,13 @@ static int __init dryice_rtc_probe(struct platform_device *pdev)
>  		goto err;
>  	}
>  
> +	rc = devm_request_irq(&pdev->dev, imxdi->sec_irq, dryice_sec_irq,
> +			IRQF_SHARED, pdev->name, imxdi);
> +	if (rc) {
> +		dev_warn(&pdev->dev, "security violation interrupt not available.\n");
> +		goto err;

If you make that error fatal, it means that the DT ABI changed. I would
simply issue the warning and continue anyway.

> +	}
> +
>  	platform_set_drvdata(pdev, imxdi);
>  	imxdi->rtc = devm_rtc_device_register(&pdev->dev, pdev->name,
>  				  &dryice_rtc_ops, THIS_MODULE);
> -- 
> 1.7.10.4
> 

-- 
Alexandre Belloni, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com