[PATCH 1/4] ARM: Add __arm_ioremap_exec for mapping external memory as MT_MEMORY

[Nicolas Pitre]

On Tue, 4 Oct 2011, Tony Lindgren wrote:

> This allows mapping external memory such as SRAM for use.
> 
> This is needed for some small chunks of code, such as reprogramming
> SDRAM memory source clocks that can't be executed in SDRAM. Other
> use cases include some PM related code.
> 
> Signed-off-by: Tony Lindgren <tony at atomide.com>

Acked-by: Nicolas Pitre <nicolas.pitre at linaro.org>

As mentioned, you might consider dropping the export until needed.


> ---
>  arch/arm/include/asm/io.h |    1 +
>  arch/arm/mm/ioremap.c     |   22 ++++++++++++++++++++++
>  2 files changed, 23 insertions(+), 0 deletions(-)
> 
> diff --git a/arch/arm/include/asm/io.h b/arch/arm/include/asm/io.h
> index d66605d..4ff152e 100644
> --- a/arch/arm/include/asm/io.h
> +++ b/arch/arm/include/asm/io.h
> @@ -80,6 +80,7 @@ extern void __iomem *__arm_ioremap_caller(unsigned long, size_t, unsigned int,
>  
>  extern void __iomem *__arm_ioremap_pfn(unsigned long, unsigned long, size_t, unsigned int);
>  extern void __iomem *__arm_ioremap(unsigned long, size_t, unsigned int);
> +extern void __iomem *__arm_ioremap_exec(unsigned long, size_t, int cached);
>  extern void __iounmap(volatile void __iomem *addr);
>  
>  /*
> diff --git a/arch/arm/mm/ioremap.c b/arch/arm/mm/ioremap.c
> index ab50627..a813658 100644
> --- a/arch/arm/mm/ioremap.c
> +++ b/arch/arm/mm/ioremap.c
> @@ -289,6 +289,28 @@ __arm_ioremap(unsigned long phys_addr, size_t size, unsigned int mtype)
>  }
>  EXPORT_SYMBOL(__arm_ioremap);
>  
> +/*
> + * Remap an arbitrary physical address space into the kernel virtual
> + * address space as memory. Needed when the kernel wants to execute
> + * code in external memory. This is needed for reprogramming source
> + * clocks that would affect normal memory for example. Please see
> + * CONFIG_GENERIC_ALLOCATOR for allocating external memory.
> + */
> +void __iomem *
> +__arm_ioremap_exec(unsigned long phys_addr, size_t size, int cached)
> +{
> +	unsigned int mtype;
> +
> +	if (cached)
> +		mtype = MT_MEMORY;
> +	else
> +		mtype = MT_MEMORY_NONCACHED;
> +
> +	return __arm_ioremap_caller(phys_addr, size, mtype,
> +			__builtin_return_address(0));
> +}
> +EXPORT_SYMBOL(__arm_ioremap_exec);
> +
>  void __iounmap(volatile void __iomem *io_addr)
>  {
>  	void *addr = (void *)(PAGE_MASK & (unsigned long)io_addr);
> 
> 
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