linux-kernel - Re: [RFC PATCH v2 4/4] arm64: qcom: add cpu operations

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Date:	Fri, 10 Apr 2015 22:57:48 +0200
From:	Arnd Bergmann <arnd@...db.de>
To:	Kumar Gala <galak@...eaurora.org>
Cc:	linux-arm-msm@...r.kernel.org,
	Abhimanyu Kapur <abhimany@...eaurora.org>,
	linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
	arm@...nel.org, devicetree@...r.kernel.org,
	catalin.marinas@....com, will.deacon@....com
Subject: Re: [RFC PATCH v2 4/4] arm64: qcom: add cpu operations

On Friday 10 April 2015 15:43:25 Kumar Gala wrote:
> +static int qcom_cpu_boot(unsigned int cpu)
> +{
> +       int ret = 0;
> +
> +       if (per_cpu(cold_boot_done, cpu) == false) {
> +               ret = qcom_unclamp_secondary_arm_cpu(cpu);
> +               if (ret)
> +                       return ret;
> +               per_cpu(cold_boot_done, cpu) = true;
> +       }
> +       return secondary_pen_release(cpu);
> +}
> +

Please add a comment here to explain why you need a two-stage process here,
rather than just booting the CPU without the secondary_pen.

Are you working around a specific silicon bug here?

	Arnd
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