From: Anand Gadiyar <gadiyar@gmail.com>
To: Sascha Hauer <s.hauer@pengutronix.de>
Cc: barebox@lists.infradead.org
Subject: Re: BeagleBoard sdrc init writes reserved values
Date: Wed, 10 Nov 2010 21:43:00 +0530 [thread overview]
Message-ID: <AANLkTikwqJckiphhidiSV=OysTQp5Jf-EWonmJTbp=Es@mail.gmail.com> (raw)
In-Reply-To: <20101110151106.GT6017@pengutronix.de>
On Wed, Nov 10, 2010 at 8:41 PM, Sascha Hauer <s.hauer@pengutronix.de> wrote:
> Hi Orjan,
>
> On Wed, Nov 10, 2010 at 09:55:21AM +0100, Orjan Friberg wrote:
>> In sdrc_init in board-beagle.c both
>>
>> writel(0x1A, SDRC_REG(SYSCONFIG));
>>
>> and
>>
>> writel(0x18, SDRC_REG(SYSCONFIG));
>>
>> sets bits 4:3 in the IDLEMODE field. The OMAP3 TRM (spruf98k) defines
>> 0x2 as the only valid value for this field, all others being marked as
>> "reserved - do not use". board-omap3evm.c does the same thing,
>> board-sdp343x.c does not.
>>
>> Anyone knows where these settings come from? Derived from an older
>> version of the TRM? (I'm thinking there may have been a feature that
>> was discovered to be unreliable or not working as intended so it was
>> removed from the docs.)
>
> I have no idea. I'm pretty sure though that the value has been copied
> from some version of U-Boot or Xloader.
>
I agree - I think this is an accident - probably copied from older loader
versions and introduced in the first version that went here.
- Anand
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next prev parent reply other threads:[~2010-11-10 16:13 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-11-10 8:55 Orjan Friberg
2010-11-10 15:11 ` Sascha Hauer
2010-11-10 16:13 ` Anand Gadiyar [this message]
2010-11-11 11:55 ` Orjan Friberg
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