Re: MMC_CAP_SDIO_IRQ for omap 3430

[Dirk Behme <dirk.behme@googlemail.com>]

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
>>
>>
> 
> 
>