Some hosts cannot do scatter/gather in hardware. Since not doing sg
is such a big performance hit, we (optionally) bounce the requests
to a simple linear buffer that we hand over to the driver.
Signed-off-by: NPierre Ossman <drzeus@drzeus.cx>

Remove dead code and unused structs from the block driver.
Signed-off-by: NPierre Ossman <drzeus@drzeus.cx>

The MMC block devices now have an assigned major. Make sure
we actually use it.
Signed-off-by: NPierre Ossman <drzeus@drzeus.cx>

Change Kconfig objects from "menu, config" into "menuconfig" so
that the user can disable the whole feature without having to
enter the menu first.
Signed-off-by: NJan Engelhardt <jengelh@gmx.de>
Signed-off-by: NPierre Ossman <drzeus@drzeus.cx>

Move protocol operations and definitions into their own files
in an effort to separate protocol handling and bus
arbitration more clearly.
Signed-off-by: NPierre Ossman <drzeus@drzeus.cx>

The classic MMC bus was defined as multi card bus
system, which is reflected in the design in the MMC
layer.

When SD showed up, the bus topology was abandoned
and a star topology (one card per host) was mandated.
MMC version 4 has followed this, officially deprecating
the bus topology.

As we do not have any known users of the bus
topology we can remove support for it. This will
simplify the code and rectify some incorrect
assumptions in the newer additions.
Signed-off-by: NPierre Ossman <drzeus@drzeus.cx>

Make sure we don't deadlock when removing a suspended block
queue, something that might happen if the card is removed during
suspend.
Signed-off-by: NPierre Ossman <drzeus@drzeus.cx>

Clean up the drivers/mmc directory by moving card and host drivers
into subdirectories.
Signed-off-by: NPierre Ossman <drzeus@drzeus.cx>