[U-Boot] [PATCH] mmc: send CMD0 before CMD1 for some MMC cards

[Yangbo Lu]

Hi Ziyuan and Jaehoon,


> -----Original Message-----
> From: Ziyuan Xu [mailto:xzy.xu at rock-chips.com]
> Sent: Wednesday, July 27, 2016 9:37 PM
> To: Jaehoon Chung; Yangbo Lu; u-boot at lists.denx.de; Tom Rini
> Cc: Pantelis Antoniou
> Subject: Re: [U-Boot] [PATCH] mmc: send CMD0 before CMD1 for some MMC
> cards
> 
> 
> 
> On 2016年07月27日 19:15, Jaehoon Chung wrote:
> > On 07/27/2016 04:28 PM, Yangbo Lu wrote:
> >> Hi Tom,
> >>
> >> Could you help to assign this mmc patch reviewing to right person?
> >> It seems no one had reviewed it for almost half year.
> >>
> >> And another my mmc patch also needs to be reviewed.
> >> I submitted in May. Please help.
> >> http://patchwork.ozlabs.org/patch/624448/
> >>
> >>
> >> Thank you very much.
> >>
> >>
> >> Best regards,
> >> Yangbo Lu
> >>
> >>> -----Original Message-----
> >>> From: Yangbo Lu [mailto:yangbo.lu at nxp.com]
> >>> Sent: Wednesday, March 09, 2016 11:00 AM
> >>> To: u-boot at lists.denx.de
> >>> Cc: Pantelis Antoniou; Yangbo Lu
> >>> Subject: [PATCH] mmc: send CMD0 before CMD1 for some MMC cards
> >>>
> >>> When the MMC framework was added in u-boot, the mmc_go_idle was
> >>> added before mmc_send_op_cond_iter in function mmc_send_op_cond
> >>> annotating that some cards seemed to need this. Actually, we still
> >>> need to do this in function mmc_complete_op_cond for those cards.
> >>> This has been verified on Micron MTFC4GACAECN eMMC chip.
> > If there is no go_idle(), then what happen?
> > If you share the information more, i can check the more..
> Sounds interesting, I also want want to know what happen?
> It seems like you failed in CMD1? The eMMC device was always in busy
> device within 1 second?

[Lu Yangbo-B47093] This was an issue which our customer reported and required us to fix in March.
They used NXP LS1020A platform and Micron MTFC4GACAECN eMMC, and reported they had to add CMD0 as below.
Otherwise it couldn’t read OCR.

static int mmc_complete_op_cond(struct mmc *mmc) {
	struct mmc_cmd cmd;
	int timeout = 1000;
	uint start;
	int err;

#if defined (XXX_CHANGED)	
	// our eMMC chip (Micron MTFC4GACAECN) requires that it be put in idle mode before
	// negociating the operating voltage levels.
	mmc_go_idle(mmc);
#endif	


I hadn’t reproduce this to get more details about this issue since I didn’t have one this kind eMMC card that time.
Thanks.

> >
> > Best Regards,
> > Jaehoon Chung
> >
> >>> Signed-off-by: Yangbo Lu <yangbo.lu at nxp.com>
> >>> ---
> >>>   drivers/mmc/mmc.c | 3 +++
> >>>   1 file changed, 3 insertions(+)
> >>>
> >>> diff --git a/drivers/mmc/mmc.c b/drivers/mmc/mmc.c index
> >>> ede5d6e..82e3268
> >>> 100644
> >>> --- a/drivers/mmc/mmc.c
> >>> +++ b/drivers/mmc/mmc.c
> >>> @@ -418,6 +418,9 @@ static int mmc_complete_op_cond(struct mmc *mmc)
> >>>   	uint start;
> >>>   	int err;
> >>>
> >>> +	/* Some cards seem to need this */
> >>> +	mmc_go_idle(mmc);
> >>> +
> >>>   	mmc->op_cond_pending = 0;
> >>>   	if (!(mmc->ocr & OCR_BUSY)) {
> >>>   		start = get_timer(0);
> >>> --
> >>> 2.1.0.27.g96db324
> >> _______________________________________________
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> >>
> >>
> >>
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