From: Scott Wood <scottwood@freescale.com>
To: Ivan Djelic <ivan.djelic@parrot.com>
Cc: Artem Bityutskiy <dedekind1@gmail.com>,
LiuShuo <b35362@freescale.com>,
Matthieu Castet <matthieu.castet@parrot.com>,
"linuxppc-dev@ozlabs.org" <linuxppc-dev@ozlabs.org>,
"linux-mtd@lists.infradead.org" <linux-mtd@lists.infradead.org>,
"dwmw2@infradead.org" <dwmw2@infradead.org>
Subject: Re: [PATCH v3] mtd/nand : workaround for Freescale FCM to support large-page Nand chip
Date: Mon, 22 Aug 2011 11:04:31 -0500 [thread overview]
Message-ID: <4E527E0F.1010500@freescale.com> (raw)
In-Reply-To: <20110822152530.GA16794@parrot.com>
On 08/22/2011 10:25 AM, Ivan Djelic wrote:
> Did you take into account the fact that because MTD thinks this a 2K chip,
> you will have to wait twice for the nand busy read time (typically 25 us) per
> each 4K read. In other words, to read 4 kBytes you will do:
>
> 1. send read0 (00), send address, send read1 (30)
> 2. wait tRB
> 3. transfer 2 kBytes
> 4. send read0 (00), send address, send read1 (30)
> 5. wait tRB
> 6. transfer 2 kBytes
>
> Same problem for writes (but rather 100 us instead of 25 us).
>
> How does that compare with hw ecc gain in terms of performance ?
We'd have the double-delay with the sw ecc plus buffering approach as well.
To eliminate it we'd need to do an extra data transfer without reissuing
the command, which Shuo was unable to get to work.
And it's not worse than having an actual 2K chip. :-)
-Scott
next prev parent reply other threads:[~2011-08-22 16:04 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-08-18 2:33 [PATCH v3] mtd/nand : workaround for Freescale FCM to support large-page Nand chip b35362
2011-08-18 16:25 ` Scott Wood
2011-08-18 18:27 ` Scott Wood
2011-08-23 8:37 ` LiuShuo
2011-08-23 10:02 ` Matthieu CASTET
2011-08-23 16:12 ` Scott Wood
2011-08-25 11:18 ` Artem Bityutskiy
2011-08-24 2:48 ` LiuShuo
2011-08-25 11:25 ` Matthieu CASTET
2011-09-01 9:41 ` LiuShuo
2011-09-01 22:30 ` Scott Wood
2011-08-18 17:00 ` Matthieu CASTET
2011-08-18 18:24 ` Scott Wood
2011-08-19 3:20 ` LiuShuo
2011-08-19 8:57 ` Matthieu CASTET
2011-08-19 18:10 ` Scott Wood
2011-08-22 10:58 ` Artem Bityutskiy
2011-08-22 15:25 ` Ivan Djelic
2011-08-22 16:04 ` Scott Wood [this message]
2011-08-22 16:13 ` Matthieu CASTET
2011-08-22 16:19 ` Scott Wood
2011-08-22 17:05 ` Matthieu CASTET
2011-08-23 3:09 ` LiuShuo
2011-08-23 8:14 ` Matthieu CASTET
2011-08-23 9:57 ` LiuShuo
2011-08-23 10:13 ` Matthieu CASTET
2011-08-22 15:58 ` Scott Wood
2011-08-25 11:06 ` Artem Bityutskiy
2011-08-22 10:53 ` Artem Bityutskiy
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=4E527E0F.1010500@freescale.com \
--to=scottwood@freescale.com \
--cc=b35362@freescale.com \
--cc=dedekind1@gmail.com \
--cc=dwmw2@infradead.org \
--cc=ivan.djelic@parrot.com \
--cc=linux-mtd@lists.infradead.org \
--cc=linuxppc-dev@ozlabs.org \
--cc=matthieu.castet@parrot.com \
/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 a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox