From: Nick Thompson <nick.thompson@ge.com>
To: u-boot@lists.denx.de
Subject: [U-Boot] Bottleneck of NAND copy speed
Date: Mon, 12 Sep 2011 13:55:45 +0100 [thread overview]
Message-ID: <4E6E0151.1050708@ge.com> (raw)
In-Reply-To: <4E6DEB26.4020409@gmail.com>
On 12/09/11 12:21, Simon Schwarz wrote:
> Hi List,
>
> ATM I'm working on a DMA transfer from NAND to RAM of the Linux-image in
> my SPL.
>
> I?m searching for the speed bottleneck of the MT29F1G16ABBHC-ET
> NAND-Flash on the devkit8000 (OMAP3).
>
> From the timings I set on the GPMC I calced a max. speed of around 26
> MiB/s. In my measurements I have a speed of around 10 MiB/s.
>
> Here is the image of my the calculation:
> https://docs.google.com/leaf?id=0B_wpO5K0MQSlYTcxMWVlOGEtY2FmYy00ODMyLWE1MTUtN2ZiZGViOWVhMzYw&hl=en_US
>
> tcmd: The time for the initial read command
> twr: time to write the address
> tDn: Time for a 16bit read of Data
>
> Does anyone has an idea where the bottleneck could be? Is my calculation
> wrong?
> (ecc is done parallel to the DMA transfer).
I only had a quick look at your calculation, but didn't notice anything to account
for the NAND copy to read cache (data ready) time of the NAND device.
Nick.
next prev parent reply other threads:[~2011-09-12 12:55 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-09-12 11:21 [U-Boot] Bottleneck of NAND copy speed Simon Schwarz
2011-09-12 11:43 ` Wolfgang Denk
2011-09-13 13:13 ` Simon Schwarz
2011-09-12 12:55 ` Nick Thompson [this message]
2011-09-13 13:18 ` Simon Schwarz
2011-09-13 19:53 ` Scott Wood
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