From: Scott Wood <scottwood@freescale.com>
To: u-boot@lists.denx.de
Subject: [U-Boot] Bottleneck of NAND copy speed
Date: Tue, 13 Sep 2011 14:53:30 -0500 [thread overview]
Message-ID: <4E6FB4BA.4060505@freescale.com> (raw)
In-Reply-To: <4E6DEB26.4020409@gmail.com>
On 09/12/2011 06:21 AM, 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).
Have you measured how much time is taken in software between each
operation -- time when the NAND chip is idle and software is either
processing the results of the last transaction or preparing for the next
one?
-Scott
prev parent reply other threads:[~2011-09-13 19:53 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
2011-09-13 13:18 ` Simon Schwarz
2011-09-13 19:53 ` Scott Wood [this message]
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