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
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:
Quoted 34 lines
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 SchwarzMATRIX VISION GmbH, Talstraße 16, DE-71570 Oppenweiler - Registergericht: Amtsgericht Stuttgart, HRB 271090 Geschäftsführer: Gerhard Thullner, Werner Armingeon, Uwe Furtner
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[email protected]
https://ozlabs.org/mailman/listinfo/linuxppc-dev
.
Fabio,
I'm running on a MPC8343.
The SD-Card is connected on the spi hardware controller.
regards,
Andr=E9
Quoted 4 lines · Fabio Tosetto
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
Quoted 9 lines
spi or psc spi?
=20
regards,
Fabio
=20
Andre Schwarz ha scritto:Quoted 3 lines
All,
has anybody made some investigations about performance of a SD/MMC car=
d
Quoted 3 lines
Quoted 3 lines
on SPI ?
Actually I'm using various cards (different speed classes) on an SPI b=
us
Quoted 2 lines
Quoted 2 lines
of a MPC8343 cpu.
Everything is working fine basically, i.e. card is detected properly a=
nd
Quoted 11 lines
Quoted 11 lines
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
Quoted 15 lines
Quoted 15 lines
spi driver/mmc layer issue ?
regards,
Andre SchwarzMATRIX 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
[email protected]
https://ozlabs.org/mailman/listinfo/linuxppc-dev
.
Quoted 2 lines
Quoted 1 line
=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