ata: add platform driver for Calxeda AHCI controller

Calxeda highbank SATA phy has intermittent problems bringing up a link
with Gen3 drives. Retrying the phy hard reset can work-around this issue,
but each reset also disables spread spectrum support. The reset function
also needs to reprogram the phy to enable spread spectrum support.

Create a new driver based on ahci_platform to support the Calxeda Highbank
SATA controller.

Signed-off-by: Mark Langsdorf <mark.langsdorf@calxeda.com>
Signed-off-by: Rob Herring <rob.herring@calxeda.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
diff --git a/drivers/ata/Kconfig b/drivers/ata/Kconfig
index 27cecd3..e08d322 100644
--- a/drivers/ata/Kconfig
+++ b/drivers/ata/Kconfig
@@ -214,6 +214,14 @@
 	help
 	  This option enables the taskfile dumping and NCQ debugging.
 
+config SATA_HIGHBANK
+	tristate "Calxeda Highbank SATA support"
+	help
+	  This option enables support for the Calxeda Highbank SoC's
+	  onboard SATA.
+
+	  If unsure, say N.
+
 config SATA_MV
 	tristate "Marvell SATA support"
 	help