Re: slow MMC over SPI
Fabio, I'm running on a MPC8343. The SD-Card is connected on the spi hardware controller. regards, André Fabio Tosetto schrieb: Hello, 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 spi or psc spi? regards, Fabio Andre Schwarz ha scritto: All, has anybody made some investigations about performance of a SD/MMC card on SPI ? Actually I'm using various cards (different speed classes) on an SPI bus of a MPC8343 cpu. Everything is working fine basically, i.e. card is detected properly and 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, Talstraße 16, DE-71570 Oppenweiler - Registergericht: Amtsgericht Stuttgart, HRB 271090 Geschäftsführer: Gerhard Thullner, Werner Armingeon, Uwe Furtner ___ Linuxppc-dev mailing list Linuxppc-dev@ozlabs.org https://ozlabs.org/mailman/listinfo/linuxppc-dev . MATRIX VISION GmbH, Talstraße 16, DE-71570 Oppenweiler - Registergericht: Amtsgericht Stuttgart, HRB 271090 Geschäftsführer: Gerhard Thullner, Werner Armingeon, Uwe Furtner ___ Linuxppc-dev mailing list Linuxppc-dev@ozlabs.org https://ozlabs.org/mailman/listinfo/linuxppc-dev
slow MMC over SPI
All, has anybody made some investigations about performance of a SD/MMC card on SPI ? Actually I'm using various cards (different speed classes) on an SPI bus of a MPC8343 cpu. Everything is working fine basically, i.e. card is detected properly and 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, Talstraße 16, DE-71570 Oppenweiler - Registergericht: Amtsgericht Stuttgart, HRB 271090 Geschäftsführer: Gerhard Thullner, Werner Armingeon, Uwe Furtner ___ Linuxppc-dev mailing list Linuxppc-dev@ozlabs.org https://ozlabs.org/mailman/listinfo/linuxppc-dev
Re: slow MMC over SPI
Hello, 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 spi or psc spi? regards, Fabio Andre Schwarz ha scritto: All, has anybody made some investigations about performance of a SD/MMC card on SPI ? Actually I'm using various cards (different speed classes) on an SPI bus of a MPC8343 cpu. Everything is working fine basically, i.e. card is detected properly and 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, Talstraße 16, DE-71570 Oppenweiler - Registergericht: Amtsgericht Stuttgart, HRB 271090 Geschäftsführer: Gerhard Thullner, Werner Armingeon, Uwe Furtner ___ Linuxppc-dev mailing list Linuxppc-dev@ozlabs.org https://ozlabs.org/mailman/listinfo/linuxppc-dev . ___ Linuxppc-dev mailing list Linuxppc-dev@ozlabs.org https://ozlabs.org/mailman/listinfo/linuxppc-dev
