[PATCH 01/52] ARM: introduce atag_offset to replace boot_params

[H Hartley Sweeten]

On Tuesday, July 05, 2011 7:47 PM, Nicolas Pitre wrote:
> The boot_params member of the mdesc structure is used to provide a
> default physical address for the ATAG list.  Since this value is fixed
> at compile time and often based on ARCH_PHYS_OFFSET, it gets in the way
> of runtime PHYS_OFFSET usage.
> 
> Let's introduce atag_offset which should contains only the relative
> offset from start of memory instead of an absolute value, in preparation
> to move all instance of boot_params over to it.
> 
> Signed-off-by: Nicolas Pitre <nicolas.pitre at linaro.org>
> ---
>  arch/arm/include/asm/mach/arch.h |    1 +
>  arch/arm/kernel/setup.c          |    2 ++
>  2 files changed, 3 insertions(+), 0 deletions(-)
> 
> diff --git a/arch/arm/include/asm/mach/arch.h b/arch/arm/include/asm/mach/arch.h
> index 7b79a00..1bdf6e1 100644
> --- a/arch/arm/include/asm/mach/arch.h
> +++ b/arch/arm/include/asm/mach/arch.h
> @@ -18,6 +18,7 @@ struct machine_desc {
>  	unsigned int		nr;		/* architecture number	*/
>  	const char		*name;		/* architecture name	*/
>  	unsigned long		boot_params;	/* tagged list		*/
> +	unsigned long		atag_offset;	/* tagged list (relative) */
>  	const char		**dt_compat;	/* array of device tree
>  						 * 'compatible' strings	*/
>  
> diff --git a/arch/arm/kernel/setup.c b/arch/arm/kernel/setup.c
> index e0db84d..4cc3e2b 100644
> --- a/arch/arm/kernel/setup.c
> +++ b/arch/arm/kernel/setup.c
> @@ -816,6 +816,8 @@ static struct machine_desc * __init setup_machine_tags(unsigned int nr)
>  
>  	if (__atags_pointer)
>  		tags = phys_to_virt(__atags_pointer);
> +	else if(mdesc->atag_offset)
> +		tags = PAGE_OFFSET + mdesc->atag_offset;

This results in a warning...

arch/arm/kernel/setup.c: In function 'setup_arch':
arch/arm/kernel/setup.c:820: warning: assignment makes pointer from integer without a cast

Regards,
Hartley