On Thu, Mar 10, 2011 at 5:29 PM, Lei Wen <[email protected]> wrote: > Hi Raffaele, > > On Thu, Mar 10, 2011 at 11:43 PM, Raffaele Recalcati > <[email protected]> wrote: >> From: Raffaele Recalcati <[email protected]> >> >> The first SEND_OP_COND (CMD1) is used only to ask card capabilities, waiting >> that the card is not busy. >> After it, an AND operation is done between card capabilities and host >> capabilities, (at the moment only for the voltage field). >> Finally the correct value is sent to the MMC. >> >> Signed-off-by: Raffaele Recalcati <[email protected]> >> --- >> drivers/mmc/mmc.c | 21 +++++++++++++++++++-- >> include/mmc.h | 2 ++ >> 2 files changed, 21 insertions(+), 2 deletions(-) >> >> diff --git a/drivers/mmc/mmc.c b/drivers/mmc/mmc.c >> index 042653f..ded630b 100644 >> --- a/drivers/mmc/mmc.c >> +++ b/drivers/mmc/mmc.c >> @@ -347,17 +347,34 @@ sd_send_op_cond(struct mmc *mmc) >> >> int mmc_send_op_cond(struct mmc *mmc) >> { >> - int timeout = 1000; >> + int timeout = 10000; >> struct mmc_cmd cmd; >> int err; >> >> /* Some cards seem to need this */ >> mmc_go_idle(mmc); >> >> + /* Asking to the card its capabilities */ >> + do { >> + cmd.cmdidx = MMC_CMD_SEND_OP_COND; >> + cmd.resp_type = MMC_RSP_R3; >> + cmd.cmdarg = 0; >> + cmd.flags = 0; >> + >> + err = mmc_send_cmd(mmc, &cmd, NULL); >> + >> + if (err) >> + return err; >> + >> + udelay(1000); >> + } while (!(cmd.response[0] & OCR_BUSY) && timeout--); > > I think you should not put the first probe a multi-time. In linux framework, > it would skip the first probing. > > I test with this patch and fail to detect my emmc card... > While just let the first probe once, it works fine. > > Best regards, > Lei >
Look at JEDEC Standard No. 84-A441 document at page 190. It is normal to ask the card capabilities before setting. But I understand also that in your case there is some issue. I'm sorry, what does "multi-time" mean? Thx, Raffaele -- www.opensurf.it _______________________________________________ U-Boot mailing list [email protected] http://lists.denx.de/mailman/listinfo/u-boot
