Re: [PATCH] cfa10036: Retrieve the RAM size at runtime

[Sascha Hauer <s.hauer@pengutronix.de>]

On Thu, Mar 21, 2013 at 04:36:38PM +0100, Alexandre Belloni wrote:
> The cfa-10036 comes in two flavours, with either 128MB or 256MB of RAM
> on it.
> 
> Since it's not stored anywhere, we need to runtime detect it by
> introducing the cfa10036_get_ram_size function which is similar to
> get_ram_size. As we run from RAM, we can then use _text and __bss_stop
> to prevent poking in the barebox memory which is not supported on other
> platforms.
> 
> Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
> Cc: Maxime Ripard <maxime.ripard@free-electrons.com>
> ---
>  arch/arm/boards/crystalfontz-cfa10036/cfa10036.c |   72 +++++++++++++++++++++-
>  1 file changed, 71 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/arm/boards/crystalfontz-cfa10036/cfa10036.c b/arch/arm/boards/crystalfontz-cfa10036/cfa10036.c
> index 1bc20cf..37cc17e 100644
> --- a/arch/arm/boards/crystalfontz-cfa10036/cfa10036.c
> +++ b/arch/arm/boards/crystalfontz-cfa10036/cfa10036.c
> @@ -39,6 +39,8 @@
>  #include <asm/armlinux.h>
>  #include <asm/mmu.h>
>  
> +#include <asm-generic/sections.h>
> +
>  #include <mach/fb.h>
>  
>  #include <generated/mach-types.h>
> @@ -90,9 +92,77 @@ static struct i2c_gpio_platform_data i2c_gpio_pdata = {
>  	.udelay			= 5,		/* ~100 kHz */
>  };
>  
> +/*
> + * Copied from get_ram_size in common/memory.c
> + */
> +long cfa10036_get_ram_size(volatile long *base, long maxsize)
> +{

When I asked for a local version of this function I had something like
this in mind, not a complete copy of the function.

	volatile u32 *base = (void *)IMX_MEMORY_BASE;
	volatile u32 *ofs = base + SZ_128M;

	*base = *ofs = 0xdeadbeef;

	*ofs = 0x11223344;
	if (*base == 0x11223344)
		return SZ_128M;
	else
		return SZ_256M;


Sascha

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