On 13 April 2016 at 13:18, Yuan, Juntao <juntao.yuan@xxxxxxxxx> wrote: > I tried both R1 and R1b for stop command of SD card. > I got plenty of warning message 'mmc1: Got data interrupt 0x00000002 even though no data operation was in progress' in console when R1 was being used for stop command. > It repeated and repeated, endlessly. Did you see this warning before? Please don't top post! I haven't seen it. It seems like a problem in the mmc host driver (I assume it's an SDHCI variant you are using). Kind regards Uffe > > > Thanks. > Juntao. > > > -----Original Message----- > From: Ulf Hansson [mailto:ulf.hansson@xxxxxxxxxx] > Sent: Wednesday, April 13, 2016 4:15 PM > To: Yuan, Juntao <juntao.yuan@xxxxxxxxx> > Cc: linux-mmc@xxxxxxxxxxxxxxx; Hunter, Adrian <adrian.hunter@xxxxxxxxx> > Subject: Re: [PATCH] mmc: block: Correct response type of stop command for sdcard > > On 13 April 2016 at 07:59, Yuan, Juntao <juntao.yuan@xxxxxxxxx> wrote: >> >> According to Physical Layer Simplified Specification Version 4.10, SD >> card needs a R1b response for stop command. > > I have looked at this earlier and I don't think R1B is needed. > > According to the Command table in the spec, where commands are listed with their corresponding response type, a CMD12 (stop) has an R1B response. As you probably know, the difference between R1 and R1B is the optional busy signalling on DAT0. > > Now, if you look into the details about READ and WRITE transfers in the spec, it becomes clear that there's a difference in the response you get from a CMD12. In the READ case there's *no* busy signalling but there is for WRITE. For that reason, using R1 in case of READ seems like the correct thing to do. > > I haven't looked at SD 4.10, but according to earlier versions you can find these details in the "Timings" section. > > I guess some comment in the code would be valuable as the spec is indeed a bit unclear, let me submit a change for it. > > Kind regards > Uffe > >> >> Signed-off-by: Yuan Juntao <juntao.yuan@xxxxxxxxx> >> --- >> drivers/mmc/card/block.c | 11 ++++++++--- >> 1 file changed, 8 insertions(+), 3 deletions(-) >> >> diff --git a/drivers/mmc/card/block.c b/drivers/mmc/card/block.c index >> 3bdbe50..aa8fc98b 100644 >> --- a/drivers/mmc/card/block.c >> +++ b/drivers/mmc/card/block.c >> @@ -1533,9 +1533,14 @@ static void mmc_blk_rw_rq_prep(struct mmc_queue_req *mqrq, >> if (rq_data_dir(req) == READ) { >> brq->cmd.opcode = readcmd; >> brq->data.flags = MMC_DATA_READ; >> - if (brq->mrq.stop) >> - brq->stop.flags = MMC_RSP_SPI_R1 | MMC_RSP_R1 | >> - MMC_CMD_AC; >> + if (brq->mrq.stop) { >> + if (mmc_card_mmc(card)) >> + brq->stop.flags = MMC_RSP_SPI_R1 | MMC_RSP_R1 | >> + MMC_CMD_AC; >> + else >> + brq->stop.flags = MMC_RSP_SPI_R1B | MMC_RSP_R1B | >> + MMC_CMD_AC; >> + } >> } else { >> brq->cmd.opcode = writecmd; >> brq->data.flags = MMC_DATA_WRITE; >> -- >> 1.7.9.5 >> >> >> >> Thanks. >> Juntao. >> -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
