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