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From: Stefan Roese <sr@denx.de>
To: u-boot@lists.denx.de
Subject: [U-Boot-Users] [PATCH] SPARC: CFI flash_read64 is defined a weak function.
Date: Sat, 29 Mar 2008 07:08:52 +0100	[thread overview]
Message-ID: <200803290708.52675.sr@denx.de> (raw)
In-Reply-To: <1206733219-23179-1-git-send-email-daniel@gaisler.com>

On Friday 28 March 2008, Daniel Hellstrom wrote:
> SPARC has implemented __raw_readq, it reads 64-bit from any 32-bit address.
> SPARC CPUs implement flash_read64 which calls __raw_readq.
>
> For current SPARC architectures (LEON2 and LEON3) each read from the
> FLASH must lead to a cache miss. This is because FLASH can not be set
> non-cacheable since program code resides there, and alternatively disabling
> cache is poor from performance view, or doing a cache flush between each
> read is even poorer.
>
> Forcing a cache miss on a SPARC is done by a special instruction "lda" -
> load alternative space, the alternative space number (ASI) is processor
> implementation spcific and can be found by including <asm/processor.h>.

Added to cfi-flash repository. Thanks.

Best regards,
Stefan

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      reply	other threads:[~2008-03-29  6:08 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-03-28 19:40 [U-Boot-Users] [PATCH] SPARC: CFI flash_read64 is defined a weak function Daniel Hellstrom
2008-03-29  6:08 ` Stefan Roese [this message]

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