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

[Alexander Motin]

Alexander Motin wrote:
> I would like to present initial revision of my generic PCI SD Host 
> Controller driver (sdhci). It support PCI devices with class 8 and 
> subclass 5 according to SD Host Controller Specification. 
> 
> Latest patches against 8-CURRENT (mostly fit 7-STABLE) may be found at:
> http://people.freebsd.org/~mav/sdhci/

For those who are not tracking actively, I would like to report that 
most of original driver's child illnesses are now healed.

Driver now supports both PIO and DMA modes. Because of some special 
tunings DMA works fine even on almost broken ENE chips. I am reaching 
15MB/s transfer (maximum for my controller's bus) with only about 1% of 
CPU load. Implemented 4 bits bus width and high speed timing modes 
support for high data rates up to 52MHz. Cards hot insertion/removing is 
now working. Together with in-tree mmc/mmcsd drivers improvements most 
of card types (SD, SDHC, standard and high capacity MMC) are now supported.

-- 
Alexander Motin