Hi,
I'm trying to use an SPI bitbang driver for PPC4xx [1] to talk to an
SD-card, and it doesn't work. Enabling debugging in the mmc-spi driver I
first saw, that the mmc layer sends MMC_GO_IDLE_STATE several times during
initialization, after which the card enters the idle state and needs time
to recover, however, the driver doesn't wait and keeps sending further
commands. I am not quite sure this is bad, because queries do get answered
(with R1_SPI_IDLE bit set), still I somehow fixed that so, that the driver
now always repeats sending SD_APP_OP_COND until the card leaves the idle
state, and then the driver proceeds. I know this is probably not a correct
fix - I don't have the MMC/SD spec, I only found [2], still now I see that
indeed the card is given a chance to initialize before any further
commands are attempted. But then I come to the next problem: when the
driver requests the card ID with MMC_SEND_CID I get an error back:
mmc0: starting CMD59 arg 00000001 flags 00000080
mmc_spi spi0.51: mmc_spi: CMD59, resp R1
mmc_spi spi0.51: spi_ppc4xx_setup: mode 0, 8 bpw, 400000 hz
mmc0: req done (CMD59): 0: 00000000 00000000 00000000 00000000
mmc_sd_init_card[376]
mmc0: starting CMD10 arg 00000000 flags 000000b5
mmc0: blksz 16 blocks 1 flags 00000200 tsac 0 ms nsac 0
mmc_spi spi0.51: mmc_spi: CMD10, resp R1
mmc_spi spi0.51: mmc_spi: read block, 16 bytes
mmc_spi spi0.51: read error ffffff92 (-110)
mmc_spi spi0.51: read status -110
mmc_spi spi0.51: spi_ppc4xx_setup: mode 0, 8 bpw, 400000 hz
mmc0: req done (CMD10): 0: 00000000 00000000 00000000 00000000
mmc0: 0 bytes transferred: -110
mmc_send_cxd_data[259] data err -110, cmd err 0
Any idea? Unfortunately, I do not have another platform where I could
verify spi-mmc. Maybe someone could send me a debug log of an SD-card
initialization in such a host? David?
Thanks
Guennadi
[1] http://article.gmane.org/gmane.linux.kernel.mentors/638 (an earlier version)
[2] http://elm-chan.org/docs/mmc/mmc_e.html
---
Guennadi Liakhovetski, Ph.D.
DENX Software Engineering GmbH, MD: Wolfgang Denk & Detlev Zundel
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: +49-8142-66989-0 Fax: +49-8142-66989-80 Email: [email protected]