[PATCH v4] ARM: l2c: add options to overwrite prefetching behavior

[f.fainelli@gmail.com (Florian Fainelli)]

On 29/05/15 16:19, Hauke Mehrtens wrote:
> These options make it possible to overwrites the data and instruction
> prefetching behavior of the arm pl310 cache controller.
> 
> Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>

Acked-by: Florian Fainelli <f.fainelli@gmail.com>

> ---
> changes since
> v3: 
>   * remove arm prefix
>   * improve documentation
> v2: only set prefetch
> v1: set prefetch and aux
>  Documentation/devicetree/bindings/arm/l2cc.txt |  5 +++++
>  arch/arm/mm/cache-l2x0.c                       | 20 ++++++++++++++++++++
>  2 files changed, 25 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/arm/l2cc.txt b/Documentation/devicetree/bindings/arm/l2cc.txt
> index 0dbabe9..2251dcc 100644
> --- a/Documentation/devicetree/bindings/arm/l2cc.txt
> +++ b/Documentation/devicetree/bindings/arm/l2cc.txt
> @@ -67,6 +67,11 @@ Optional properties:
>    disable if zero.
>  - arm,prefetch-offset : Override prefetch offset value. Valid values are
>    0-7, 15, 23, and 31.
> +- prefetch-data : Data prefetch. Value: <0> (forcibly disable), <1>
> +  (forcibly enable), property absent (retain settings set by firmware)
> +- prefetch-instr : Instruction prefetch. Value: <0> (forcibly disable),
> +  <1> (forcibly enable), property absent (retain settings set by
> +  firmware)
>  
>  Example:
>  
> diff --git a/arch/arm/mm/cache-l2x0.c b/arch/arm/mm/cache-l2x0.c
> index e309c8f..2570f83 100644
> --- a/arch/arm/mm/cache-l2x0.c
> +++ b/arch/arm/mm/cache-l2x0.c
> @@ -1199,6 +1199,26 @@ static void __init l2c310_of_parse(const struct device_node *np,
>  		pr_err("L2C-310 OF arm,prefetch-offset property value is missing\n");
>  	}
>  
> +	ret = of_property_read_u32(np, "prefetch-data", &val);
> +	if (ret == 0) {
> +		if (val)
> +			prefetch |= L310_PREFETCH_CTRL_DATA_PREFETCH;
> +		else
> +			prefetch &= ~L310_PREFETCH_CTRL_DATA_PREFETCH;
> +	} else if (ret != -EINVAL) {
> +		pr_err("L2C-310 OF prefetch-data property value is missing\n");
> +	}
> +
> +	ret = of_property_read_u32(np, "prefetch-instr", &val);
> +	if (ret == 0) {
> +		if (val)
> +			prefetch |= L310_PREFETCH_CTRL_INSTR_PREFETCH;
> +		else
> +			prefetch &= ~L310_PREFETCH_CTRL_INSTR_PREFETCH;
> +	} else if (ret != -EINVAL) {
> +		pr_err("L2C-310 OF prefetch-instr property value is missing\n");
> +	}
> +
>  	l2x0_saved_regs.prefetch_ctrl = prefetch;
>  }
>  
> 


-- 
Florian