[U-Boot] [PATCH] ARMv8:ls2-2080a: Implement core ERRATA 829520, 833471

[Ashish Kumar]

Please see inline

Regards
Ashish

-----Original Message-----
From: york sun [mailto:york.sun at nxp.com] 
Sent: Tuesday, January 19, 2016 10:34 PM
To: Ashish Kumar <Ashish.Kumar at freescale.com>; u-boot at lists.denx.de
Subject: Re: [PATCH] ARMv8:ls2-2080a: Implement core ERRATA 829520, 833471

On 01/17/2016 11:15 PM, Ashish Kumar wrote:
>  * 829520: Code bounded by indirect conditional branch might corrupt instruction stream,
>     Workaround: Set CPUACTLR_EL1[4] = 1'b1 to disable the Indirect 
> Predictor
> 
>  * 833471: VMSR FPSCR functional failure or deadlock
>     Workaround: Set CPUACTLR[38] to 1, which forces FPSCR write flush
> 
> Signed-off-by: Ashish Kumar <Ashish.Kumar at freescale.com>
> ---
>  arch/arm/cpu/armv8/start.S       |   20 ++++++++++++++++++++
>  include/configs/ls2080a_common.h |    2 ++
>  2 files changed, 22 insertions(+), 0 deletions(-)
> 
> diff --git a/arch/arm/cpu/armv8/start.S b/arch/arm/cpu/armv8/start.S 
> index da45d98..dd583c9 100644
> --- a/arch/arm/cpu/armv8/start.S
> +++ b/arch/arm/cpu/armv8/start.S
> @@ -132,6 +132,26 @@ apply_a57_core_errata:
>  	msr	S3_1_c15_c2_0, x0	/* cpuactlr_el1 */
>  #endif
>  
> +#ifdef CONFIG_ARM_ERRATA_833471
> +	mrs	x0, S3_1_c15_c2_0	/* cpuactlr_el1 */
> +	/* FPSCR write flush.
> +	 * Note that in some cases where a flush is unnecessary this
> +	    could impact performance. */
> +	orr	x0, x0, #1 << 38
> +	msr	S3_1_c15_c2_0, x0	/* cpuactlr_el1 */
> +#endif
> +
> +#ifdef CONFIG_ARM_ERRATA_829520
> +	mrs	x0, S3_1_c15_c2_0	/* cpuactlr_el1 */
> +	/* Disable Indirect Predictor bit will prevent this erratum
> +	    from occurring
> +	 * Note that in some cases where a flush is unnecessary this
> +	    could impact performance. */
> +	orr	x0, x0, #1 << 4
> +	msr	S3_1_c15_c2_0, x0	/* cpuactlr_el1 */
> +#endif
> +
> +
>  #ifdef CONFIG_ARM_ERRATA_833069
>  	mrs	x0, S3_1_c15_c2_0	/* cpuactlr_el1 */
>  	/* Disable Enable Invalidates of BTB bit */ diff --git 
> a/include/configs/ls2080a_common.h b/include/configs/ls2080a_common.h
> index a503934..9ab5d97 100644
> --- a/include/configs/ls2080a_common.h
> +++ b/include/configs/ls2080a_common.h
> @@ -18,6 +18,8 @@
>  /* Errata fixes */
>  #define CONFIG_ARM_ERRATA_828024
>  #define CONFIG_ARM_ERRATA_826974
> +#define CONFIG_ARM_ERRATA_833471
> +#define CONFIG_ARM_ERRATA_829520
>  

This seems to be a wrong location. This file is for board (common part for multiple boards).

[Ashish]Could you please elaborate more? Errata is valid for both ls2080/ls2085, in fact it is errata/bug in arm-v8 core

York