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From: Detlev Zundel <dzu@denx.de>
To: u-boot@lists.denx.de
Subject: [U-Boot] [PATCH v2 2/3] avr32: Use uncached() macro to get an address for SDRAM init
Date: Fri, 13 Aug 2010 13:01:25 +0200	[thread overview]
Message-ID: <m262zewzcq.fsf@ohwell.denx.de> (raw)
In-Reply-To: <20100813105606.2e8e656d@hskinnemoen-d830> (Haavard Skinnemoen's message of "Fri, 13 Aug 2010 10:56:06 +0700")

Hi Haavard,

> Detlev Zundel <dzu@denx.de> wrote:
>> So this patch replaces a construct which seems to be valid over all
>> architectures by a construct which is only used in avr32, right?  It
>> also deletes the explicit statement that such a mapping is not needed
>> any further.
>
> Problem is that in order to make the CFI driver work on avr32, we need
> to change the map_physmem() macro to return the physical address
> unchanged.

I see.  And I presume you cannot tell the situation apart inside
map_physmem?

>> Isn't this a step backward?  Can't you put the functionality inside the
>> map function and leave the unmap a noop?
>
> I agree it's a step backward, but since the previous flamewar didn't
> get us anywhere, I decided to go for a compromise this time. At least
> this small architecture-specific kludge is localized to
> architecture-specific code.
>
> The map_physmem() macro currently does exactly the same thing as the
> uncached() macro, and the unmap is a noop, but the next patch changes
> it in order to fix the CFI driver. If the next patch is applied without
> this patch being applied first, the SDRAM driver will do cached
> accesses during initialization, and that may cause the initialization
> to fail.

Why not include a note to this extent into the git commit message?  This
would be a great help for other people to later understand why this
change has been done the "backward way" that it was.

Cheers
  Detlev

-- 
vi vi vi - the roman numeral of the beast.
--
DENX Software Engineering GmbH,      MD: Wolfgang Denk & Detlev Zundel
HRB 165235 Munich,  Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-40 Fax: (+49)-8142-66989-80 Email: dzu at denx.de

  reply	other threads:[~2010-08-13 11:01 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-08-12  6:52 [U-Boot] [PATCH v2 0/3] avr32: simple paging support Haavard Skinnemoen
2010-08-12  6:52 ` [U-Boot] [PATCH v2 1/3] avr32: Print unrelocated PC on exception Haavard Skinnemoen
2010-09-03 11:51   ` Reinhard Meyer
2010-09-03 13:19     ` Andreas Bießmann
2010-09-03 14:37   ` Reinhard Meyer
2010-08-12  6:52 ` [U-Boot] [PATCH v2 2/3] avr32: Use uncached() macro to get an address for SDRAM init Haavard Skinnemoen
2010-08-12 15:04   ` Detlev Zundel
2010-08-13  3:56     ` Haavard Skinnemoen
2010-08-13 11:01       ` Detlev Zundel [this message]
2010-08-13 12:12         ` Haavard Skinnemoen
2010-08-13 13:01           ` Detlev Zundel
2010-09-03 11:16   ` Andreas Bießmann
2010-09-03 14:37   ` Reinhard Meyer
2010-08-12  6:52 ` [U-Boot] [PATCH v2 3/3] avr32: Add simple paging support Haavard Skinnemoen
2010-09-03 11:10   ` Andreas Bießmann
2010-09-03 14:38   ` Reinhard Meyer

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