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? 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. > ��.n��������+%������w��{.n�����{��i��)�� jg��� �����ݢj����G���� ���j:+v���w�m������w�������h�����٥
