On 1 August 2015 at 11:01, Hans de Goede <hdegoede@xxxxxxxxxx> wrote: > Hi, > > On 21-07-15 14:15, Ulf Hansson wrote: >> >> On 10 July 2015 at 17:14, Hans de Goede <hdegoede@xxxxxxxxxx> wrote: >>> >>> Some sdio wifi modules have not been working reliable with the sunxi-mmc >>> host code. This turns out to be caused by it starting new commands while >>> the card signals that it is still busy processing a previous command. >> >> >> Which are those commands? > > > The code were things get stuck when not waiting for the busy signal uses > the following sdio helper functions: > > sdio_readb/sdio_writeb > sdio_f0_readb/sdio_f0_writeb > sdio_readw/sdio_writew > sdio_readl/sdio_writel > sdio_readsb > sdio_memcpy_fromio/sdio_memcpy_toio > > And directly issues the following command: > > mmc_dat.flags = write ? MMC_DATA_WRITE : MMC_DATA_READ; > mmc_cmd.opcode = SD_IO_RW_EXTENDED; > mmc_cmd.arg = write ? 1<<31 : 0; /* write flag */ > mmc_cmd.arg |= (fn & 0x7) << 28; /* SDIO func num */ > mmc_cmd.arg |= 1<<27; /* block mode */ > /* for function 1 the addr will be incremented */ > mmc_cmd.arg |= (fn == 1) ? 1<<26 : 0; > mmc_cmd.flags = MMC_RSP_SPI_R5 | MMC_RSP_R5 | MMC_CMD_ADTC; > > I do not know if the busy wait is necessary for all > of these, but the hack in the android kernel code, > which inserts calls to a wait_card_busy function directly > into: drivers/net/wireless/brcm80211/brcmfmac/bcmsdh.c > > Does so for all of these. > >> Or more interesting, which response types do >> >> these commands expect? >> I don't think this is a sunxi specific issue, I have seen similar >> issues for other host controllers. > > > Agreed, recent dw-mmc patches address the same issue, also involving > broadcom sdio wifi chips. > >> I am thinking that perhaps this should be managed by the mmc core >> instead of local hacks to sunxi. Potentially we could make the core to >> invoke the already existing host_ops->card_busy() callback when >> needed... > > > I'm fine with solving this either way, implementing host_ops->card_busy() > for sunxi is easy, and if the core os modified to call that function > before issue sdio io ops (which seems to be the common thing here), > then that indeed is better then having the sunxi code always do > the busy check. Okay, so let's make the core to call the ->card_busy() callback and then it's up to each host driver to implement that callback. As an optimization, we might consider (in a separate step) to add MMC_RSP_BUSY to the response type. I realize that would somewhat be a violation of the spec, but apparently the SDIO spec isn't really clear on this area. > >> Within this context, could I ask whether you controller supports IRQ >> based HW-busy detection? Or you need polling of the status register? > > > I'm afraid that we need to poll the status register. I've been unable > to find an irq flag corresponding to this. Okay, thanks for the info. [...] Kind regards Uffe -- 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
