From: Simon Schwarz <simonschwarzcor@googlemail.com>
To: u-boot@lists.denx.de
Subject: [U-Boot] Bottleneck of NAND copy speed
Date: Tue, 13 Sep 2011 15:18:54 +0200 [thread overview]
Message-ID: <4E6F583E.9070804@gmail.com> (raw)
In-Reply-To: <4E6E0151.1050708@ge.com>
On 09/12/2011 02:55 PM, Nick Thompson wrote:
> 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.
Ahh you mean t_R (Page read time) right?
Taking this into account I would expect something around 19,45 MiB/s.
Thank you!
Simon
next prev parent reply other threads:[~2011-09-13 13:18 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 [this message]
2011-09-13 19:53 ` Scott Wood
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=4E6F583E.9070804@gmail.com \
--to=simonschwarzcor@googlemail.com \
--cc=u-boot@lists.denx.de \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.