libata/drivers: Add driver for Apple "MacIO" IDE controller

This is a libata driver for the "macio" IDE controller used on most Apple
PowerMac and PowerBooks. It's a libata equivalent of drivers/ide/ppc/pmac.c

It supports all the features of its predecessor, including mediabay hotplug
and suspend/resume. It should also support module load/unload.

The timing calculations have been simplified to use pre-calculated tables
compared to drivers/ide/pmac.c and it uses the new mediabay interface
provided by a previous patch.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Acked-by: Tejun Heo <tj@kernel.org>
diff --git a/drivers/ata/Kconfig b/drivers/ata/Kconfig
index f2df6e2..51eea30 100644
--- a/drivers/ata/Kconfig
+++ b/drivers/ata/Kconfig
@@ -781,5 +781,15 @@
 
 	  If unsure, say N.
 
+config PATA_MACIO
+	tristate "Apple PowerMac/PowerBook internal 'MacIO' IDE"
+	depends on PPC_PMAC
+	help
+	  Most IDE capable PowerMacs have IDE busses driven by a variant
+          of this controller which is part of the Apple chipset used on
+          most PowerMac models. Some models have multiple busses using
+          different chipsets, though generally, MacIO is one of them.
+
+
 endif # ATA_SFF
 endif # ATA