Subject: [PATCH 1/2] ARM: realview: Fix PBX-A9 cache description

From: [email-masked] (Robin Murphy)
Date: Fri, 15 Jul 2016 18:45:32 +0100

On 15/07/16 13:19, Robin Murphy wrote:
> Clearly QEMU is very permissive in how its PL310 model may be set up,
> but the real hardware turns out to be far more particular about things
> actually being correct. Fix up the DT description so that the real
> thing actually boots:
> 
> - The arm,data-latency and arm,tag-latency properties need 3 cells to
>   be valid, otherwise we end up retaining the default 8-cycle latencies
>   which leads pretty quickly to lockup.
> - The arm,dirty-latency property is only relevant to L210/L220, so get
>   rid of it.
> - The cache geometry override also leads to lockup and/or general
>   misbehaviour. Irritatingly, the manual doesn't state the actual PL310
>   configuration, but based on the boardfile code and poking registers
>   from the Boot Monitor, it would seem to be 8 sets of 16KB ways.

FWIW, after an afternoon of bothering people I've tracked down the
original spec for the test chip, and can confirm that the configuration
is indeed 8x16KB with parity disabled.

Robin.

> With that, we can successfully boot to enjoy the fun of mismatched FPUs...
> 
> Signed-off-by: Robin Murphy <[email-masked]>
> ---
>  arch/arm/boot/dts/arm-realview-pbx-a9.dts | 9 ++++-----
>  1 file changed, 4 insertions(+), 5 deletions(-)
> 
> diff --git a/arch/arm/boot/dts/arm-realview-pbx-a9.dts b/arch/arm/boot/dts/arm-realview-pbx-a9.dts
> index db808f92dd79..90d00b407f85 100644
> --- a/arch/arm/boot/dts/arm-realview-pbx-a9.dts
> +++ b/arch/arm/boot/dts/arm-realview-pbx-a9.dts
> @@ -70,13 +70,12 @@
>  		 * associativity as these may be erroneously set
>  		 * up by boot loader(s).
>  		 */
> -		cache-size = <1048576>; // 1MB
> -		cache-sets = <4096>;
> +		cache-size = <131072>; // 128KB
> +		cache-sets = <512>;
>  		cache-line-size = <32>;
>  		arm,parity-disable;
> -		arm,tag-latency = <1>;
> -		arm,data-latency = <1 1>;
> -		arm,dirty-latency = <1>;
> +		arm,tag-latency = <1 1 1>;
> +		arm,data-latency = <1 1 1>;
>  	};
>  
>  	scu: scu at 1f000000 {
>