Re: [PATCH] arm64: dts: r8a7795: Increase the size of GIC-400 mapped registers

[Simon Horman <horms@verge.net.au>]

Hi Dirk,

I understand that there is an issue here but I'm not yet able
to convince myself that this is the correct solution.

In revision r0p1 of the CoreLink GIC-400 Generic Interrupt Controller
Technical Reference Manual[1] I see in Section 3.2. "GIC-400 register map"
that the size of both the CPU interfaces and Virtual CPU interfaces are
0x2000 bytes. And assuming that the hardware follows the specification it
appears that DT is correctly describing the hardware.

[1] http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.ddi0471b/index.html

On Tue, Apr 19, 2016 at 08:29:55AM +0200, Dirk Behme wrote:
> From: Pooya Keshavarzi <Pooya.Keshavarzi@de.bosch.com>
> 
> There are some requirements about the GIC-400 memory layout and its
> mapping if using 64k aligned base addresses like on r8a7795.
> 
> See e.g.
> 
> http://xenbits.xen.org/gitweb/?p=xen.git;a=commit;h=21550029f709072aacf3b9
> 
> Map the whole memory range instead of only 0x2000. This will fix
> the issue that some hypervisors, e.g. Xen, fail to handle the
> interrupts correctly.
> 
> Signed-off-by: Pooya Keshavarzi <Pooya.Keshavarzi@de.bosch.com>
> Signed-off-by: Dirk Behme <dirk.behme@de.bosch.com>
> ---
> Note: This patch is against renesas-drivers-2016-04-12-v4.6-rc3
> 
>  arch/arm64/boot/dts/renesas/r8a7795.dtsi | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/arm64/boot/dts/renesas/r8a7795.dtsi b/arch/arm64/boot/dts/renesas/r8a7795.dtsi
> index 8be9424..d880fd4 100644
> --- a/arch/arm64/boot/dts/renesas/r8a7795.dtsi
> +++ b/arch/arm64/boot/dts/renesas/r8a7795.dtsi
> @@ -160,9 +160,9 @@
>  			#address-cells = <0>;
>  			interrupt-controller;
>  			reg = <0x0 0xf1010000 0 0x1000>,
> -			      <0x0 0xf1020000 0 0x2000>,
> +			      <0x0 0xf1020000 0 0x20000>,
>  			      <0x0 0xf1040000 0 0x20000>,
> -			      <0x0 0xf1060000 0 0x2000>;
> +			      <0x0 0xf1060000 0 0x20000>;
>  			interrupts = <GIC_PPI 9
>  					(GIC_CPU_MASK_SIMPLE(4) | IRQ_TYPE_LEVEL_HIGH)>;
>  		};
> -- 
> 2.8.0
>