Date: Thu, 23 Feb 2012 04:28:20 +0100
From: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
To: Ryan Mallon <rmallon@gmail.com>
Cc: Nicolas Ferre <nicolas.ferre@atmel.com>,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org,
        linux@arm.linux.org.uk
Subject: Re: [PATCH v2 16/19] ARM: at91: merge SRAM Memory banks thanks to
 mirroring
Message-ID: <20120223032820.GC20176@game.jcrosoft.org>
References: <1329903585-30738-1-git-send-email-nicolas.ferre@atmel.com>
 <0290a1a8c53da6ce02ef9b6f2447ba2da0859dc6.1329903206.git.nicolas.ferre@atmel.com>
 <4F4576A6.3090901@gmail.com>
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On 10:13 Thu 23 Feb     , Ryan Mallon wrote:
> On 22/02/12 20:39, Nicolas Ferre wrote:
> 
> > From: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
> > 
> > On at91sam9260 and at91sam9g20 the SRAM banks are mirrored. We can
> > merge them together to be able to have bigger and continuous
> > internal RAM.
> > 
> > Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
> > Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
> > ---
> >  arch/arm/mach-at91/at91sam9260.c              |   13 +++++--------
> >  arch/arm/mach-at91/include/mach/at91sam9260.h |    4 ++++
> >  2 files changed, 9 insertions(+), 8 deletions(-)
> > 
> > diff --git a/arch/arm/mach-at91/at91sam9260.c b/arch/arm/mach-at91/at91sam9260.c
> > index 14882ae..4ade265 100644
> > --- a/arch/arm/mach-at91/at91sam9260.c
> > +++ b/arch/arm/mach-at91/at91sam9260.c
> > @@ -310,15 +310,12 @@ static void __init at91sam9xe_map_io(void)
> >  
> >  static void __init at91sam9260_map_io(void)
> >  {
> > -	if (cpu_is_at91sam9xe()) {
> > +	if (cpu_is_at91sam9xe())
> >  		at91sam9xe_map_io();
> > -	} else if (cpu_is_at91sam9g20()) {
> > -		at91_init_sram(0, AT91SAM9G20_SRAM0_BASE, AT91SAM9G20_SRAM0_SIZE);
> > -		at91_init_sram(1, AT91SAM9G20_SRAM1_BASE, AT91SAM9G20_SRAM1_SIZE);
> > -	} else {
> > -		at91_init_sram(0, AT91SAM9260_SRAM0_BASE, AT91SAM9260_SRAM0_SIZE);
> > -		at91_init_sram(1, AT91SAM9260_SRAM1_BASE, AT91SAM9260_SRAM1_SIZE);
> > -	}
> > +	else if (cpu_is_at91sam9g20())
> > +		at91_init_sram(0, AT91SAM9G20_SRAM_BASE, AT91SAM9G20_SRAM_SIZE);
> > +	else
> > +		at91_init_sram(0, AT91SAM9260_SRAM_BASE, AT91SAM9260_SRAM_SIZE);
> >  }
> >  
> >  static void __init at91sam9260_ioremap_registers(void)
> > diff --git a/arch/arm/mach-at91/include/mach/at91sam9260.h b/arch/arm/mach-at91/include/mach/at91sam9260.h
> > index 2e47b6d..08ae9af 100644
> > --- a/arch/arm/mach-at91/include/mach/at91sam9260.h
> > +++ b/arch/arm/mach-at91/include/mach/at91sam9260.h
> > @@ -113,6 +113,8 @@
> >  #define AT91SAM9260_SRAM0_SIZE	SZ_4K		/* Internal SRAM 0 size (4Kb) */
> >  #define AT91SAM9260_SRAM1_BASE	0x00300000	/* Internal SRAM 1 base address */
> >  #define AT91SAM9260_SRAM1_SIZE	SZ_4K		/* Internal SRAM 1 size (4Kb) */
> > +#define AT91SAM9260_SRAM_BASE	0x002FF000	/* Internal SRAM base address */
> > +#define AT91SAM9260_SRAM_SIZE	SZ_8K		/* Internal SRAM size (8Kb) */
> 
> >  
> >  #define AT91SAM9260_UHP_BASE	0x00500000	/* USB Host controller */
> >  
> > @@ -126,6 +128,8 @@
> >  #define AT91SAM9G20_SRAM0_SIZE	SZ_16K		/* Internal SRAM 0 size (16Kb) */
> >  #define AT91SAM9G20_SRAM1_BASE	0x00300000	/* Internal SRAM 1 base address */
> >  #define AT91SAM9G20_SRAM1_SIZE	SZ_16K		/* Internal SRAM 1 size (16Kb) */
> > +#define AT91SAM9G20_SRAM_BASE	0x002FC000	/* Internal SRAM base address */
> > +#define AT91SAM9G20_SRAM_SIZE	SZ_32K		/* Internal SRAM size (32Kb) */
> 
> 
> Where does the SRAM_BASE value come from? The at91sam9g20 guide says
> that the region 0x204000 - 0x2fffff is reserved, and I can't find any
> information in the at91sam9g20 guide about the sram being mirrored. Can
> you point me to some documentation for this?
This is not documented but it's correct

Best Regards,
J.
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