[PATCH] ARM: map ATAGs when not in first 1MB of RAM

[Grant Likely]

On Thu, Jan 27, 2011 at 09:50:43AM -0600, Rob Herring wrote:
> From: Rob Herring <rob.herring at calxeda.com>
> 
> If ATAGs or DTB pointer is not within first 1MB of RAM, then the boot params
> will not be mapped early enough, so map the 1MB region that r2 points to. Only
> map the first 1MB when r2 is 0.
> 
> Some assembly improvements from Nicolas Pitre.
> 
> Signed-off-by: Rob Herring <rob.herring at calxeda.com>

I'll try temporarily picking this one up into my devicetree/test
branch until Russell's p2v patches get merged into mainline.

Thanks!
g.

> ---
>  arch/arm/kernel/head.S |   19 ++++++++++++++++++-
>  1 files changed, 18 insertions(+), 1 deletions(-)
> 
> diff --git a/arch/arm/kernel/head.S b/arch/arm/kernel/head.S
> index 65d9489..9c688bf 100644
> --- a/arch/arm/kernel/head.S
> +++ b/arch/arm/kernel/head.S
> @@ -205,15 +205,32 @@ __create_page_tables:
>  #endif
>  
>  	/*
> -	 * Then map first 1MB of ram in case it contains our boot params.
> +	 * Then map first 1MB of ram if boot params address is not specified.
>  	 */
> +	cmp	r2, #0
> +	bne	1f
>  	add	r0, r4, #PAGE_OFFSET >> 18
>  	orr	r6, r7, #(PHYS_OFFSET & 0xff000000)
>  	.if	(PHYS_OFFSET & 0x00f00000)
>  	orr	r6, r6, #(PHYS_OFFSET & 0x00f00000)
>  	.endif
>  	str	r6, [r0]
> +	b	2f
>  
> +	/*
> +	 * Otherwise map the 1MB region r2 points to (atags or dtb)
> +	 */
> +1:	mov	r0, r2, lsr #20
> +	mov	r0, r0, lsl #20
> +	sub	r3, r0, #(PHYS_OFFSET & 0xff000000)
> +	.if	(PHYS_OFFSET & 0x00f00000)
> +	sub	r3, r3, #(PHYS_OFFSET & 0x00f00000)
> +	.endif
> +	add	r3, r3, #PAGE_OFFSET
> +	add	r3, r4, r3, lsr #18
> +	orr	r6, r7, r0
> +	str	r6, [r3]
> +2:
>  #ifdef CONFIG_DEBUG_LL
>  #ifndef CONFIG_DEBUG_ICEDCC
>  	/*
> -- 
> 1.7.1
> 
> 
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