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Groups > linux.kernel > #1615121 > unrolled thread

[PATCH 1/1] arm64: tegra: fix PPI interrupt flag

Started byAniruddha Banerjee <aniruddhab@nvidia.com>
First post2017-04-03 13:30 +0200
Last post2017-04-03 15:20 +0200
Articles 3 — 3 participants

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  [PATCH 1/1] arm64: tegra: fix PPI interrupt flag Aniruddha Banerjee <aniruddhab@nvidia.com> - 2017-04-03 13:30 +0200
    Re: [PATCH 1/1] arm64: tegra: fix PPI interrupt flag Jon Hunter <jonathanh@nvidia.com> - 2017-04-03 15:00 +0200
      Re: [PATCH 1/1] arm64: tegra: fix PPI interrupt flag Marc Zyngier <marc.zyngier@arm.com> - 2017-04-03 15:20 +0200

#1615121 — [PATCH 1/1] arm64: tegra: fix PPI interrupt flag

FromAniruddha Banerjee <aniruddhab@nvidia.com>
Date2017-04-03 13:30 +0200
Subject[PATCH 1/1] arm64: tegra: fix PPI interrupt flag
Message-ID<ts8lk-6bt-25@gated-at.bofh.it>
The interrupt flag for PPI should not be set to any value, since the
register is read-only. Fix the flags for the PPI interrupts to
IRQ_TYPE_NONE, so that there is no write to the read-only register.

Signed-off-by: Aniruddha Banerjee <aniruddhab@nvidia.com>
---
 arch/arm64/boot/dts/nvidia/tegra132.dtsi | 8 ++++----
 arch/arm64/boot/dts/nvidia/tegra186.dtsi | 8 ++++----
 arch/arm64/boot/dts/nvidia/tegra210.dtsi | 8 ++++----
 3 files changed, 12 insertions(+), 12 deletions(-)

diff --git a/arch/arm64/boot/dts/nvidia/tegra132.dtsi b/arch/arm64/boot/dts/nvidia/tegra132.dtsi
index 3f3a46a4bd01..219fb3c6a273 100644
--- a/arch/arm64/boot/dts/nvidia/tegra132.dtsi
+++ b/arch/arm64/boot/dts/nvidia/tegra132.dtsi
@@ -1093,13 +1093,13 @@
 	timer {
 		compatible = "arm,armv7-timer";
 		interrupts = <GIC_PPI 13
-				(GIC_CPU_MASK_SIMPLE(4) | IRQ_TYPE_LEVEL_LOW)>,
+				(GIC_CPU_MASK_SIMPLE(4) | IRQ_TYPE_NONE)>,
 			     <GIC_PPI 14
-				(GIC_CPU_MASK_SIMPLE(4) | IRQ_TYPE_LEVEL_LOW)>,
+				(GIC_CPU_MASK_SIMPLE(4) | IRQ_TYPE_NONE)>,
 			     <GIC_PPI 11
-				(GIC_CPU_MASK_SIMPLE(4) | IRQ_TYPE_LEVEL_LOW)>,
+				(GIC_CPU_MASK_SIMPLE(4) | IRQ_TYPE_NONE)>,
 			     <GIC_PPI 10
-				(GIC_CPU_MASK_SIMPLE(4) | IRQ_TYPE_LEVEL_LOW)>;
+				(GIC_CPU_MASK_SIMPLE(4) | IRQ_TYPE_NONE)>;
 		interrupt-parent = <&gic>;
 	};
 };
diff --git a/arch/arm64/boot/dts/nvidia/tegra186.dtsi b/arch/arm64/boot/dts/nvidia/tegra186.dtsi
index 62fa85ae0271..e602299f7694 100644
--- a/arch/arm64/boot/dts/nvidia/tegra186.dtsi
+++ b/arch/arm64/boot/dts/nvidia/tegra186.dtsi
@@ -390,13 +390,13 @@
 	timer {
 		compatible = "arm,armv8-timer";
 		interrupts = <GIC_PPI 13
-				(GIC_CPU_MASK_SIMPLE(4) | IRQ_TYPE_LEVEL_LOW)>,
+				(GIC_CPU_MASK_SIMPLE(4) | IRQ_TYPE_NONE)>,
 			     <GIC_PPI 14
-				(GIC_CPU_MASK_SIMPLE(4) | IRQ_TYPE_LEVEL_LOW)>,
+				(GIC_CPU_MASK_SIMPLE(4) | IRQ_TYPE_NONE)>,
 			     <GIC_PPI 11
-				(GIC_CPU_MASK_SIMPLE(4) | IRQ_TYPE_LEVEL_LOW)>,
+				(GIC_CPU_MASK_SIMPLE(4) | IRQ_TYPE_NONE)>,
 			     <GIC_PPI 10
-				(GIC_CPU_MASK_SIMPLE(4) | IRQ_TYPE_LEVEL_LOW)>;
+				(GIC_CPU_MASK_SIMPLE(4) | IRQ_TYPE_NONE)>;
 		interrupt-parent = <&gic>;
 	};
 };
diff --git a/arch/arm64/boot/dts/nvidia/tegra210.dtsi b/arch/arm64/boot/dts/nvidia/tegra210.dtsi
index 2f832df29da8..6f3060b40a40 100644
--- a/arch/arm64/boot/dts/nvidia/tegra210.dtsi
+++ b/arch/arm64/boot/dts/nvidia/tegra210.dtsi
@@ -1214,13 +1214,13 @@
 	timer {
 		compatible = "arm,armv8-timer";
 		interrupts = <GIC_PPI 13
-				(GIC_CPU_MASK_SIMPLE(4) | IRQ_TYPE_LEVEL_LOW)>,
+				(GIC_CPU_MASK_SIMPLE(4) | IRQ_TYPE_NONE)>,
 			     <GIC_PPI 14
-				(GIC_CPU_MASK_SIMPLE(4) | IRQ_TYPE_LEVEL_LOW)>,
+				(GIC_CPU_MASK_SIMPLE(4) | IRQ_TYPE_NONE)>,
 			     <GIC_PPI 11
-				(GIC_CPU_MASK_SIMPLE(4) | IRQ_TYPE_LEVEL_LOW)>,
+				(GIC_CPU_MASK_SIMPLE(4) | IRQ_TYPE_NONE)>,
 			     <GIC_PPI 10
-				(GIC_CPU_MASK_SIMPLE(4) | IRQ_TYPE_LEVEL_LOW)>;
+				(GIC_CPU_MASK_SIMPLE(4) | IRQ_TYPE_NONE)>;
 		interrupt-parent = <&gic>;
 	};
 
-- 
2.11.0

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#1615179

FromJon Hunter <jonathanh@nvidia.com>
Date2017-04-03 15:00 +0200
Message-ID<ts9Kq-6Yw-15@gated-at.bofh.it>
In reply to#1615121
Adding Marc ...

On 03/04/17 12:19, Aniruddha Banerjee wrote:
> The interrupt flag for PPI should not be set to any value, since the
> register is read-only. Fix the flags for the PPI interrupts to
> IRQ_TYPE_NONE, so that there is no write to the read-only register.

If the below matches the h/w default, does this really cause a problem?

Note, we will not attempt to write the type if it matches the current
programmed type.

I had thought that the in DT file, the type for the PPI should align
with the h/w default in the case where it cannot be written. However, I
guess this is not explicitly stated anywhere I have found, but at the
same time the binding doc for the arm,gic.txt does not list
"IRQ_TYPE_NONE" as an option.

Marc, what are your thoughts?

> Signed-off-by: Aniruddha Banerjee <aniruddhab@nvidia.com>
> ---
>  arch/arm64/boot/dts/nvidia/tegra132.dtsi | 8 ++++----
>  arch/arm64/boot/dts/nvidia/tegra186.dtsi | 8 ++++----
>  arch/arm64/boot/dts/nvidia/tegra210.dtsi | 8 ++++----
>  3 files changed, 12 insertions(+), 12 deletions(-)
> 
> diff --git a/arch/arm64/boot/dts/nvidia/tegra132.dtsi b/arch/arm64/boot/dts/nvidia/tegra132.dtsi
> index 3f3a46a4bd01..219fb3c6a273 100644
> --- a/arch/arm64/boot/dts/nvidia/tegra132.dtsi
> +++ b/arch/arm64/boot/dts/nvidia/tegra132.dtsi
> @@ -1093,13 +1093,13 @@
>  	timer {
>  		compatible = "arm,armv7-timer";
>  		interrupts = <GIC_PPI 13
> -				(GIC_CPU_MASK_SIMPLE(4) | IRQ_TYPE_LEVEL_LOW)>,
> +				(GIC_CPU_MASK_SIMPLE(4) | IRQ_TYPE_NONE)>,
>  			     <GIC_PPI 14
> -				(GIC_CPU_MASK_SIMPLE(4) | IRQ_TYPE_LEVEL_LOW)>,
> +				(GIC_CPU_MASK_SIMPLE(4) | IRQ_TYPE_NONE)>,
>  			     <GIC_PPI 11
> -				(GIC_CPU_MASK_SIMPLE(4) | IRQ_TYPE_LEVEL_LOW)>,
> +				(GIC_CPU_MASK_SIMPLE(4) | IRQ_TYPE_NONE)>,
>  			     <GIC_PPI 10
> -				(GIC_CPU_MASK_SIMPLE(4) | IRQ_TYPE_LEVEL_LOW)>;
> +				(GIC_CPU_MASK_SIMPLE(4) | IRQ_TYPE_NONE)>;
>  		interrupt-parent = <&gic>;
>  	};
>  };
> diff --git a/arch/arm64/boot/dts/nvidia/tegra186.dtsi b/arch/arm64/boot/dts/nvidia/tegra186.dtsi
> index 62fa85ae0271..e602299f7694 100644
> --- a/arch/arm64/boot/dts/nvidia/tegra186.dtsi
> +++ b/arch/arm64/boot/dts/nvidia/tegra186.dtsi
> @@ -390,13 +390,13 @@
>  	timer {
>  		compatible = "arm,armv8-timer";
>  		interrupts = <GIC_PPI 13
> -				(GIC_CPU_MASK_SIMPLE(4) | IRQ_TYPE_LEVEL_LOW)>,
> +				(GIC_CPU_MASK_SIMPLE(4) | IRQ_TYPE_NONE)>,
>  			     <GIC_PPI 14
> -				(GIC_CPU_MASK_SIMPLE(4) | IRQ_TYPE_LEVEL_LOW)>,
> +				(GIC_CPU_MASK_SIMPLE(4) | IRQ_TYPE_NONE)>,
>  			     <GIC_PPI 11
> -				(GIC_CPU_MASK_SIMPLE(4) | IRQ_TYPE_LEVEL_LOW)>,
> +				(GIC_CPU_MASK_SIMPLE(4) | IRQ_TYPE_NONE)>,
>  			     <GIC_PPI 10
> -				(GIC_CPU_MASK_SIMPLE(4) | IRQ_TYPE_LEVEL_LOW)>;
> +				(GIC_CPU_MASK_SIMPLE(4) | IRQ_TYPE_NONE)>;
>  		interrupt-parent = <&gic>;
>  	};
>  };
> diff --git a/arch/arm64/boot/dts/nvidia/tegra210.dtsi b/arch/arm64/boot/dts/nvidia/tegra210.dtsi
> index 2f832df29da8..6f3060b40a40 100644
> --- a/arch/arm64/boot/dts/nvidia/tegra210.dtsi
> +++ b/arch/arm64/boot/dts/nvidia/tegra210.dtsi
> @@ -1214,13 +1214,13 @@
>  	timer {
>  		compatible = "arm,armv8-timer";
>  		interrupts = <GIC_PPI 13
> -				(GIC_CPU_MASK_SIMPLE(4) | IRQ_TYPE_LEVEL_LOW)>,
> +				(GIC_CPU_MASK_SIMPLE(4) | IRQ_TYPE_NONE)>,
>  			     <GIC_PPI 14
> -				(GIC_CPU_MASK_SIMPLE(4) | IRQ_TYPE_LEVEL_LOW)>,
> +				(GIC_CPU_MASK_SIMPLE(4) | IRQ_TYPE_NONE)>,
>  			     <GIC_PPI 11
> -				(GIC_CPU_MASK_SIMPLE(4) | IRQ_TYPE_LEVEL_LOW)>,
> +				(GIC_CPU_MASK_SIMPLE(4) | IRQ_TYPE_NONE)>,
>  			     <GIC_PPI 10
> -				(GIC_CPU_MASK_SIMPLE(4) | IRQ_TYPE_LEVEL_LOW)>;
> +				(GIC_CPU_MASK_SIMPLE(4) | IRQ_TYPE_NONE)>;
>  		interrupt-parent = <&gic>;
>  	};

Cheers
Jon

-- 
nvpublic

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#1615193

FromMarc Zyngier <marc.zyngier@arm.com>
Date2017-04-03 15:20 +0200
Message-ID<tsa3M-7m2-23@gated-at.bofh.it>
In reply to#1615179
On 03/04/17 13:55, Jon Hunter wrote:
> Adding Marc ...
> 
> On 03/04/17 12:19, Aniruddha Banerjee wrote:
>> The interrupt flag for PPI should not be set to any value, since the
>> register is read-only. Fix the flags for the PPI interrupts to
>> IRQ_TYPE_NONE, so that there is no write to the read-only register.
> 
> If the below matches the h/w default, does this really cause a problem?
> 
> Note, we will not attempt to write the type if it matches the current
> programmed type.
> 
> I had thought that the in DT file, the type for the PPI should align
> with the h/w default in the case where it cannot be written. However, I
> guess this is not explicitly stated anywhere I have found, but at the
> same time the binding doc for the arm,gic.txt does not list
> "IRQ_TYPE_NONE" as an option.
> 
> Marc, what are your thoughts?

My immediate answer is "Why?".

As you pointed out, we don't even try to program the GICD_ICFGR1
register if what we read from it is the right thing. Also, the GICv2
spec says in 4.3.13: "For PPIs, it is IMPLEMENTATION DEFINED whether the
most significant bit of the Int_config field is programmable.".

So NONE is always wrong (because there is no such thing in the HW), and
the DT should have a setting that matches the HW even GICD_ICFGR1 is RO
(the OS may need to know how the triggering configuration anyhow).

Aniruddha: what problem are you trying to solve here? The DT you're
touching seems just fine to me...

Thanks,

	M.
-- 
Jazz is not dead. It just smells funny...

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