RFC: MMC stack under CAM

[kibab]

Summary

An attempt to create a new version of MMC stack that uses a CAM framework to route the requests and replies.
This version is a first prototype. At this point I really want a broader review to determine if the development direction is correct. For example, we could consider the separate thread for mmcprobe to send synchronous XPT_MMC_IO requests (we cannot do it now since the request returns CAM_INPROG and we have to complete the request at another place in the code)

• Runs on the BeagleBone Black and uses a modified version of ti_sdhci driver to communicate with the card. Changes to the driver are minimal and can be ported to another SDHCI implementation easily.
• The card is initialized only if it is inserted in the MMC slot on boot.
• No MMC support, only SD.
• The initialization process is not finished yet, the card only reports its OCR

Test Plan

1. Build armv6 kernel , kernel config file is BEAGLEBONE
2. Boot the BBB with the SDHC card inserted

[imp]

First pass only for the obvious stuff / questions.
More to follow mid next week.

sys/Makefile

59

This isn't related.

sys/amd64/conf/GENERIC

359

Not related, right?

sys/arm/conf/BEAGLEBONE

75

Not really related, right?

sys/cam/mmc/mmc.h

24

This disclaimer doesn't make sense for this file.

sys/cam/mmc/mmc_all.h

24

Ditto.

sys/cam/mmc/mmc_xpt.c

14

I think there should be the SD Group disclaimer here.

sys/conf/files

94

So is this additional? Or just for SD cards that want to optionally add the bus? If it is now required, more config files need updating... And this likely needs mmc or something optional like that too.

[kibab]

D4761 completely supersedes this.