[RFC PATCH] Consolidate SRAM support

Russell King - ARM Linux linux at arm.linux.org.uk
Fri Apr 15 12:03:39 EDT 2011

On Fri, Apr 15, 2011 at 08:39:55AM -0500, Rob Herring wrote:
> Russell,
> On 04/15/2011 08:06 AM, Russell King - ARM Linux wrote:
>> This is work in progress.
>> We have two SoCs using SRAM, both with their own allocation systems,
>> and both with their own ways of copying functions into the SRAM.
> It's more than that. Several i.MX chips use plat-mxc/iram_alloc.c.

Hmm, that's nice - except for one issue.  According to my grep of
arch/arm/ and drivers/, nothing uses iram_alloc().  So, does anything in
the MX stuff use iram_alloc.c, or is it dead code left over from a
previous experiment?

The commit says:

    ARM: imx: Add iram allocator functions

    Add IRAM(Internal RAM) allocation functions using GENERIC_ALLOCATOR.
    The allocation size is 4KB multiples to guarantee alignment. The
    idea for these functions is for i.MX platforms to use them
    to dynamically allocate IRAM usage.

    Applies on 2.6.36-rc7

> lpc32xx and pnx4008 also use iram, but do not have an allocator (only 1  
> user). Both are doing a copy the suspend code to IRAM and run it which  
> may also be a good thing to have generic code for. Several i.MX chips  
> also need to run from IRAM for suspend.

We have support for copying functions to other bits of memory and getting
the Thumb-ness right - see asm/fncpy.h.  So that's a separate patch to
convert them over.

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