Re: [BUG] CMD52 sent as first command not CMD0

Chris Ball
2011-02-06T01:50:07Z

Hi,

On Sat, Feb 05, 2011 at 05:35:46PM -0800, Philip Rakity wrote:
>
> proposed solution: I cannot verify this fix until Monday.
> =====
>
> CMD52 is a reset for SDIO cards. CMD0 is not sufficient when
> the card is being re-initialized. Only send CMD52 if
> a) doing a reinitialize
> b) card is SDIO or SDIO_COMBO
>
> Signed-off-by: Philip Rakity <prakity@marvell.com>
> ---
> drivers/mmc/core/core.c | 7 ++++++-
> 1 files changed, 6 insertions(+), 1 deletions(-)
>
> diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
> index 30d4da4..f0ce6f6 100644
> --- a/drivers/mmc/core/core.c
> +++ b/drivers/mmc/core/core.c
> @@ -1521,7 +1521,12 @@ static int mmc_rescan_try_freq(struct mmc_host *host, unsigned freq)
> mmc_hostname(host), __func__, host->f_init);
> #endif
> mmc_power_up(host);
> - sdio_reset(host);
> +
> + /* reset sdio before CMD0 when card is being reinitialized */
> + if (host->card &&
> + (host->card->type == MMC_TYPE_SDIO ||
> + host->card->type == MMC_TYPE_SD_COMBO))
> + sdio_reset(host);
> mmc_go_idle(host);
> mmc_hwungate_clock(host);
>

Thanks. We have macros for this, but need to add one for combo cards.
include/linux/mmc/card.h should get:

#define mmc_card_sd_combo(c) ((c)->type == MMC_TYPE_SD_COMBO)

and then:

/* reset sdio before CMD0 when card is being reinitialized */
if (host->card && (mmc_card_sdio(host->card) ||
mmc_card_sd_combo(host->card)))
sdio_reset(host);

(FYI your hwgate patches are applied above but aren't in mainline yet.)

--
Chris Ball <cjb@laptop.org> <http://printf.net/>
One Laptop Per Child