linux-kernel - Re: [PATCH v5 1/9] arm64: dts: exynos: Add dts files for 64-bit Exynos5433 SoC

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Message-ID: <20150305185407.GK14093@leverpostej>
Date:	Thu, 5 Mar 2015 18:54:07 +0000
From:	Mark Rutland <mark.rutland@....com>
To:	Chanwoo Choi <cwchoi00@...il.com>
Cc:	Chanwoo Choi <cw00.choi@...sung.com>,
	"kgene@...nel.org" <kgene@...nel.org>,
	Marc Zyngier <Marc.Zyngier@....com>,
	"arnd@...db.de" <arnd@...db.de>, "olof@...om.net" <olof@...om.net>,
	Catalin Marinas <Catalin.Marinas@....com>,
	Will Deacon <Will.Deacon@....com>,
	"inki.dae@...sung.com" <inki.dae@...sung.com>,
	"chanho61.park@...sung.com" <chanho61.park@...sung.com>,
	"sw0312.kim@...sung.com" <sw0312.kim@...sung.com>,
	"jh80.chung@...sung.com" <jh80.chung@...sung.com>,
	"ideal.song@...sung.com" <ideal.song@...sung.com>,
	"a.kesavan@...sung.com" <a.kesavan@...sung.com>,
	"devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
	"linux-arm-kernel@...ts.infradead.org" 
	<linux-arm-kernel@...ts.infradead.org>,
	"linux-samsung-soc@...r.kernel.org" 
	<linux-samsung-soc@...r.kernel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v5 1/9] arm64: dts: exynos: Add dts files for 64-bit
 Exynos5433 SoC

Hi,

> >> >> +       psci {
> >> >> +               compatible = "arm,psci";
> >> >> +               method = "smc";
> >> >> +               cpu_off = <0x84000002>;
> >> >> +               cpu_on = <0xC4000003>;
> >> >> +       };
> >> >
> >> > Back at v2 you mentioned that CPU_OFF wasn't working [1].
> >> >
> >> > Do both CPU_ON and CPU_OFF work for all CPUs, including the boot CPU?
> >>
> >> The CPU1 ~ CPU7 are well woking about CPU_ON/OFF.
> >> CPU0 (boot CPU) is only well working for CPU_OFF.
> >> But when I try to turn on the CPU0 after CPU_OFF, I failed it.
> >
> > That's rather worrying. Can you look into what's going on here? I'd
> > rather not have dts describing things which are known to be broken.
> 
> The board dts don't include any node for CPU_ON/OFF.

I don't understand. The CPU_ON and CPU_OFF IDs are in the psci node
quoted above, and all the CPUs had enable-method = "psci".

> When I try to turn on the CPU0 (boot CPU), fail to turn on and lockup happen.
> After lockup happen, I cannot use the console.

That sounds like a pretty major bug.

Are you able to investigate with a hardware debugger?

Do other CPUs eventually log errors regarding the lockup? Or is the
machine completely dead from this point on?

> >> > I take it CPUs boot at EL2?
> >
> > Do the CPUs boot at EL1 or EL2?
> 
> Unfortunately, I cannot check the secure firmware for Exynos5433 SoC.
> I think that a few SoC provider probably would know it.

I guess I asked the wrong question.

Do CPUs enter the kernel at EL2 or at EL1?

Thanks,
Mark.
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