Re: MMC_CAP_SDIO_IRQ for omap 3430

Dirk Behme
2009-10-16T19:29:22Z

Madhusudhan Chikkature wrote:
> Hi Dirk,
>
> I am inlining the patch so that it helps review.
...
> @@ -1165,8 +1178,15 @@ static void omap_hsmmc_set_ios(struct mm
> break;
> case MMC_BUS_WIDTH_4:
> OMAP_HSMMC_WRITE(host->base, CON, con & ~DW8);
> - OMAP_HSMMC_WRITE(host->base, HCTL,
> - OMAP_HSMMC_READ(host->base, HCTL) | FOUR_BIT);
> + if (mmc_card_sdio(host->mmc->card)) {
>
> I wish it could be moved to "enable_sdio_irq" so that we can avoid inclusion of
> card.h and checking the type of card in the host controller driver.

Yes, this would be the real clean way. But ...

> But the
> dependancy on 4-bit seems to be a problem here.

... most probably we have to find a workaround until (if ever?) above
clean implementation is available.

What we need is after SDIO mode and bus width is known, and before the
first interrupt comes, to set IBG.

> On the problems being discussed on testing is the interrupt source geting
> cleared at the SDIO card level upon genaration of the CIRQ? If not it remains
> asserted.

Yes, this seems to be exactly the problem John reports in his follow
up mail.

Any hint how to clear SDIO interrupt?

Many thanks

Dirk

> + OMAP_HSMMC_WRITE(host->base, HCTL,
> + OMAP_HSMMC_READ(host->base, HCTL)
> + | IBG | FOUR_BIT);
> + } else {
> + OMAP_HSMMC_WRITE(host->base, HCTL,
> + OMAP_HSMMC_READ(host->base, HCTL)
> + | FOUR_BIT);
> + }
> break;
> case MMC_BUS_WIDTH_1:
> OMAP_HSMMC_WRITE(host->base, CON, con & ~DW8);
> @@ -1512,6 +1532,24 @@ static int omap_hsmmc_disable_fclk(struc
> return 0;
> }
>
> +static void omap_hsmmc_enable_sdio_irq(struct mmc_host *mmc, int enable)
> +{
> + struct omap_hsmmc_host *host = mmc_priv(mmc);
> + u32 ie, ise;
> +
> + ise = OMAP_HSMMC_READ(host->base, ISE);
> + ie = OMAP_HSMMC_READ(host->base, IE);
> +
> + if (enable) {
> + OMAP_HSMMC_WRITE(host->base, ISE, ise | CIRQ_ENABLE);
> + OMAP_HSMMC_WRITE(host->base, IE, ie | CIRQ_ENABLE);
> + } else {
> + OMAP_HSMMC_WRITE(host->base, ISE, ise & ~CIRQ_ENABLE);
> + OMAP_HSMMC_WRITE(host->base, IE, ie & ~CIRQ_ENABLE);
> + }
> +
> +}
> +
> static const struct mmc_host_ops omap_hsmmc_ops = {
> .enable = omap_hsmmc_enable_fclk,
> .disable = omap_hsmmc_disable_fclk,
> @@ -1519,7 +1557,7 @@ static const struct mmc_host_ops omap_hs
> .set_ios = omap_hsmmc_set_ios,
> .get_cd = omap_hsmmc_get_cd,
> .get_ro = omap_hsmmc_get_ro,
> - /* NYET -- enable_sdio_irq */
> + .enable_sdio_irq = omap_hsmmc_enable_sdio_irq,
> };
>
> static const struct mmc_host_ops omap_hsmmc_ps_ops = {
> @@ -1529,7 +1567,7 @@ static const struct mmc_host_ops omap_hs
> .set_ios = omap_hsmmc_set_ios,
> .get_cd = omap_hsmmc_get_cd,
> .get_ro = omap_hsmmc_get_ro,
> - /* NYET -- enable_sdio_irq */
> + .enable_sdio_irq = omap_hsmmc_enable_sdio_irq,
> };
>
> #ifdef CONFIG_DEBUG_FS
> @@ -1734,7 +1772,7 @@ static int __init omap_hsmmc_probe(struc
> mmc->max_seg_size = mmc->max_req_size;
>
> mmc->caps |= MMC_CAP_MMC_HIGHSPEED | MMC_CAP_SD_HIGHSPEED |
> - MMC_CAP_WAIT_WHILE_BUSY;
> + MMC_CAP_WAIT_WHILE_BUSY | MMC_CAP_SDIO_IRQ;
>
> if (mmc_slot(host).wires >= 8)
> mmc->caps |= MMC_CAP_8_BIT_DATA;
>
>
>
>
>
>> John Rigby wrote:
>>> I have seen several discussions about lack of sdio irq support in the
>>> hsmmc driver but no patches. Has anyone on this list implemented this
>>> and/or can anyone point me to patches?
>> What a coincidence ;)
>>
>> I'm currently working on this. See attachment what I currently have.
>> It is compile tested only against recent omap linux head. I don't have
>> a board using SDIO at the moment, so no real testing possible :(
>>
>> Some background, maybe it helps people to step in:
>>
>> Gumstix OMAP3 based Overo air board connects Marvell 88W8686 wifi by
>> MMC port 2 in 4 bit configuration [1]. The wifi performance is quite
>> bad (~100kB/s). There is some rumor that this might be SDIO irq
>> related [2]. There was an attempt to fix this [3] already, but this
>> doesn't work [4]. Having this, I started to look into it.
>>
>> I used [3], the TI Davinci driver [5] (supporting SDIO irq), the SDIO
>> Simplified Specification [6] and the OMAP35x TRM [7] as starting points.
>>
>> Unfortunately, the Davinci MMC registers and irqs are different
>> (Davinci has a dedicated SDIO irq). But combining [3] and [5] helps to
>> get an idea what has to be done.
>>
>> I think the main issues of [3] were that it doesn't enable IBG for 4
>> bit mode ([6] chapter 8.1.2) and that mmc_omap_irq() doesn't reset the
>> irq bits.
>>
>> Topics I still open:
>>
>> - Is it always necessary to deal with IE _and_ ISE register? I'm not
>> totally clear what the difference between these two registers are ;)
>> And in which order they have to be set.
>>
>> - Davinci driver [5] in line 1115 checks for data line to call
>> mmc_signal_sdio_irq() for irq enable.
>>
>> - Davinci driver deals with SDIO in xfer_done() (line 873)
>>
>> - Davinci driver sets block size to 64 if SDIO in line 701
>>
>> It would be quite nice if anybody likes to comment on attachment and
>> help testing.
>>
>> Many thanks and best regards
>>
>> Dirk
>>
>> [1] http://gumstix.net/wiki/index.php?title=Overo_Wifi
>>
>> [2] http://groups.google.com/group/beagleboard/msg/14e822778c5eeb56
>>
>> [3] http://groups.google.com/group/beagleboard/msg/d0eb69f4c20673be
>>
>> [4] http://groups.google.com/group/beagleboard/msg/5cdfe2a319531937
>>
>> [5]
>> http://arago-project.org/git/projects/?p=linux-davinci.git;a=blob;f=drivers/mmc/host/davinci_mmc.c;h=1bf0587250614c6d8abfe02028b96e0e47148ac8;hb=HEAD
>>
>> [6] http://www.sdcard.org/developers/tech/sdio/sd_bluetooth_spec/
>>
>> [7] http://focus.ti.com/lit/ug/spruf98c/spruf98c.pdf
>>
>>
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