From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from p15137414.pureserver.info (matrixvision.de [217.160.213.229]) by ozlabs.org (Postfix) with ESMTP id E60B5DDE08 for ; Tue, 3 Jun 2008 17:39:28 +1000 (EST) Message-ID: <4844F52D.8050203@matrix-vision.de> Date: Tue, 03 Jun 2008 09:39:25 +0200 From: =?ISO-8859-15?Q?Andr=E9_Schwarz?= MIME-Version: 1.0 To: Fabio Tosetto Subject: Re: slow MMC over SPI References: <4843AD1C.4010901@matrix-vision.de> <4844DC96.6060807@libero.it> In-Reply-To: <4844DC96.6060807@libero.it> Content-Type: text/plain; charset=ISO-8859-15; format=flowed Cc: linux-ppc list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , 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