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From: Marek Vasut <marex@denx.de>
To: u-boot@lists.denx.de
Subject: [U-Boot] [PATCH] arm: pxa: PXA270 D-Cache as ram
Date: Tue, 21 May 2013 12:54:59 +0200	[thread overview]
Message-ID: <201305211254.59982.marex@denx.de> (raw)
In-Reply-To: <1369132962.20319.3.camel@host5.omatika.ru>

Dear Sergey Yanovich,

> Dear Marek Vasut,
> 
> On Tue, 2013-05-21 at 12:39 +0200, Marek Vasut wrote:
> > > 2.2.5.2 of Marvell PXA27x Processor Family Developers Manual says:
> > > "The PXA27x processor cache configuration is identical to that of
> > > the PXA255 processor."
> > > 
> > > As a result, it is perfectly legitimate to use PXA25X
> > > 'lock_cache_for_stack' on PXA27X as well.
> > 
> > Why would you need this on PXA27x ? Is SRAM not enough?
> 
> SRAM is battery-backup.

SRAM is just the in-CPU bit of fast RAM. What do you mean by "battery-backup" ?

> It can be used as a ultra-fast persistent
> storage in OS. Wasting a quater of it just to boot the system isn't the
> best choice.

The SRAM is used for stack in U-Boot until you leave board_init_f, then the 
stack is relocated to DRAM. The OS can use SRAM as needed, U-Boot is no longer 
operational once you load subsequent OS. What's the problem?

Best regards,
Marek Vasut

  reply	other threads:[~2013-05-21 10:54 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-05-20 22:06 [U-Boot] [PATCH] arm: pxa: PXA270 D-Cache as ram Sergey Yanovich
2013-05-21 10:39 ` Marek Vasut
2013-05-21 10:42   ` Sergey Yanovich
2013-05-21 10:54     ` Marek Vasut [this message]
2013-05-21 11:23       ` Sergey Yanovich
2013-05-21 11:38         ` Marek Vasut
2013-05-21 11:56           ` Sergey Yanovich
2013-05-21 15:00             ` Marek Vasut
2013-05-21 16:31               ` Sergey Yanovich
2013-05-21 19:02                 ` Marek Vasut
2013-05-21 19:18                   ` Sergey Yanovich
2013-05-21 19:24                     ` Marek Vasut
2013-05-21 19:42                       ` Sergey Yanovich
2013-05-21 20:07                         ` Marek Vasut
2013-05-21 20:24                           ` Sergey Yanovich
2013-05-21 21:38                             ` Marek Vasut
2013-05-22 13:02                               ` Sergey Yanovich
2013-05-22 13:04                                 ` Marek Vasut
2013-05-22 13:21                                   ` Sergey Yanovich
2013-05-22 13:54                                     ` Marek Vasut
2013-05-23 17:43                               ` Mike Dunn

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