From: "André Schwarz" <andre.schwarz@matrix-vision.de>
To: Fabio Tosetto <tosettofabio83@libero.it>
Cc: linux-ppc list <linuxppc-dev@ozlabs.org>
Subject: Re: slow MMC over SPI
Date: Tue, 03 Jun 2008 09:39:25 +0200 [thread overview]
Message-ID: <4844F52D.8050203@matrix-vision.de> (raw)
In-Reply-To: <4844DC96.6060807@libero.it>
Fabio,
I'm running on a MPC8343.
The SD-Card is connected on the spi hardware controller.
regards,
Andr=E9
Fabio Tosetto schrieb:
> Hello,
>=20
> I am trying to enable the SD over SPI on a emebedded system with one
> processor powerpc mpc5200b; you have enabled mmc over spi into a native=
=20
> spi or psc spi?
>=20
> regards,
> Fabio
>=20
> Andre Schwarz ha scritto:
>> All,
>>
>> has anybody made some investigations about performance of a SD/MMC car=
d
>> on SPI ?
>>
>> Actually I'm using various cards (different speed classes) on an SPI b=
us
>> of a MPC8343 cpu.
>> Everything is working fine basically, i.e. card is detected properly a=
nd
>> block device can be mounted and used.
>>
>> SPI clock is adjusted to the card's capabilities and is running quite
>> fast (>30MHz).
>>
>> But between consecutive reads/writes there's a fixed gap of 2us thus
>> yielding a poor performance of approx. 300KBytes/sec.
>> The spi bus is utilized only ~10%.
>>
>> Any ideas where this comes from ?
>> Ist it a fixed delay regarding to some kind of spec or is it possibly =
a
>> spi driver/mmc layer issue ?
>>
>>
>> regards,
>> Andre Schwarz
>>
>> MATRIX VISION GmbH, Talstra=DFe 16, DE-71570 Oppenweiler -=20
>> Registergericht: Amtsgericht Stuttgart, HRB 271090
>> Gesch=E4ftsf=FChrer: Gerhard Thullner, Werner Armingeon, Uwe Furtner
>> _______________________________________________
>> Linuxppc-dev mailing list
>> Linuxppc-dev@ozlabs.org
>> https://ozlabs.org/mailman/listinfo/linuxppc-dev
>> .
>>
>> =20
>=20
MATRIX VISION GmbH, Talstra=DFe 16, DE-71570 Oppenweiler - Registergeric=
ht: Amtsgericht Stuttgart, HRB 271090
Gesch=E4ftsf=FChrer: Gerhard Thullner, Werner Armingeon, Uwe Furtner
prev parent reply other threads:[~2008-06-03 7:39 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-06-02 8:19 slow MMC over SPI Andre Schwarz
2008-06-03 5:54 ` Fabio Tosetto
2008-06-03 7:39 ` André Schwarz [this message]
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=4844F52D.8050203@matrix-vision.de \
--to=andre.schwarz@matrix-vision.de \
--cc=linuxppc-dev@ozlabs.org \
--cc=tosettofabio83@libero.it \
/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.