From mboxrd@z Thu Jan  1 00:00:00 1970
From: khilman@deeprootsystems.com (Kevin Hilman)
Date: Tue, 07 Dec 2010 16:56:51 -0800
Subject: Problem with sram size on OMAP1611 (OSK)
In-Reply-To: <20101207001831.GX8345@atomide.com>
References: <4CE73921.6030908@am.sony.com> <20101207001831.GX8345@atomide.com>
Message-ID: <1291769811.2796.39.camel@localhost>
To: linux-arm-kernel@lists.infradead.org
List-Id: linux-arm-kernel.lists.infradead.org

On Mon, 2010-12-06 at 16:18 -0800, Tony Lindgren wrote:
> Hi,
> 
> * Tim Bird <tim.bird@am.sony.com> [101119 18:48]:
> > Santosh,
> > 
> > I just tried the latest kernel (well, v2.6.36), and found a problem
> > that bisected to the following commit:
> > 
> > commit e546f21b4b7af012d9f18edad6237339adfeb681
> > Author: Santosh Shilimkar <santosh.shilimkar@ti.com>
> > Date:   Fri Sep 24 07:19:49 2010 +0100
> > 
> >     ARM: 6408/1: omap: Map only available sram memory
> > 
> > I am testing Linux on an OSK board (with an OMAP1611),
> > and the above commmit causes the machine to hang.
> > I isolated the problem to the sram length.  The commit
> > above changes it to a value detected in omap_detect_sram(),
> > but when this value is used, my OSK hangs on boot.
> > 
> > Below is the hack I used to work around this.  I'm not sure
> > what the problem is, but I'd be happy to provide more information
> > or try other things, to fix support for omap1611 in mainline.
> > I tried putting the 1024 * 1024 value into omap_detect_sram(),
> > with no luck.  There's some additional processing there which
> > might alter the value.  Or perhaps the current value there
> > for omap_sram_size on a 1611 is just wrong.
> > 
> > diff --git a/arch/arm/plat-omap/sram.c b/arch/arm/plat-omap/sram.c
> > index 10b3b4c..d4ba4fa 100644
> > --- a/arch/arm/plat-omap/sram.c
> > +++ b/arch/arm/plat-omap/sram.c
> > @@ -236,6 +236,8 @@ void __init omap_map_sram(void)
> >         base = ROUND_DOWN(base, PAGE_SIZE);
> >         omap_sram_io_desc[0].pfn = __phys_to_pfn(base);
> >         omap_sram_io_desc[0].length = ROUND_DOWN(omap_sram_size, PAGE_SIZE);
> > +       if (cpu_is_omap1611())
> > +               omap_sram_io_desc[0].length = 1024 * 1024;
> >         iotable_init(omap_sram_io_desc, ARRAY_SIZE(omap_sram_io_desc));
> > 
> >         printk(KERN_INFO "SRAM: Mapped pa 0x%08lx to va 0x%08lx size: 0x%lx\n",
> 
> I'm not seeing this on my OSK, can you please check if this still
> happening with v2.6.37-rc4?

I have the same problem as Tim on my OSK using latest l-o master.
Debugging this with Tony, we realized his OSK has a 1623 whereas mine
(and presumably Tim's) has an omap1611.  The SRAM code uses different
SRAM sizes for 1611 and 1610/1623.

I have no idea what the "right" values of the SRAM size are for these
parts.  

Setting it to 256k got it booting for me, so will send a patch for that
shortly.

Kevin