RFC: PCI SD host controller driver & mmc/mmcsd modules improvements

[Alexander Motin]

Carlos A. M. dos Santos wrote:
> Here goes a good suggestion: do not forget to load the module, you
> dumb ass! Now I got this:
> 
> sdhci0: <RICOH R5C822 SD> mem 0xe4103000-0xe41030ff irq 19 at device 6.3 on pci2
> sdhci0: Reserved 0x100 bytes for rid 0x10 type 3 at 0xe4103000
> sdhci0: 1 slot(s) allocated
> sdhci0: [MPSAFE]
> sdhci0: [ITHREAD]
> mmc0: <MMC/SD bus> on sdhci0
> mmc0: Reset 0x6 never completed - 0x6.

Looks like there is several version of this controller requiring special 
driver quirks. At least Linux driver includes several. I have 
implemented some, so you can try to play with them.

> Much better. However, I got a system crash and reboot attempting to
> unload the module.

I have rewritten detach function.

PS: Also I have implemented card insert/remove in a way specific for 
this device via mmc bus attach/detach. Not sure it is the best way for 
mmc subsystem generally, but it recommended by SD Host controller 
specification and works for now.

-- 
Alexander Motin