fsi: Add ast2600 master driver

The ast2600 BMC has a pair of FSI masters in it, behind an AHB to OPB
bridge.

The master driver supports reads and writes of full words, half word and
byte accesses to remote CFAMs. It can perform very basic error recovery
through resetting of the FSI port when an error is detected, and the
issuing of breaks and terms.
Signed-off-by: Joel Stanley <joel@jms.id.au>
Acked-by: Alistair Popple <alistair@popple.id.au>
--
v2:
 - remove debugging
 - squash in fixes
Link: https://lore.kernel.org/r/20191108051945.7109-10-joel@jms.id.auSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/fsi/Kconfig

@@ -53,6 +53,14 @@ config FSI_MASTER_AST_CF
 	lines driven by the internal ColdFire coprocessor. This requires
 	the corresponding machine specific ColdFire firmware to be available.
 
+config FSI_MASTER_ASPEED
+	tristate "FSI ASPEED master"
+	help
+	 This option enables a FSI master that is present behind an OPB bridge
+	 in the AST2600.
+
+	 Enable it for your BMC kernel in an OpenPower or IBM Power system.
+
 config FSI_SCOM
 	tristate "SCOM FSI client device driver"
 	---help---

drivers/fsi/Makefile

@@ -2,6 +2,7 @@
 
 obj-$(CONFIG_FSI) += fsi-core.o
 obj-$(CONFIG_FSI_MASTER_HUB) += fsi-master-hub.o
+obj-$(CONFIG_FSI_MASTER_ASPEED) += fsi-master-aspeed.o
 obj-$(CONFIG_FSI_MASTER_GPIO) += fsi-master-gpio.o
 obj-$(CONFIG_FSI_MASTER_AST_CF) += fsi-master-ast-cf.o
 obj-$(CONFIG_FSI_SCOM) += fsi-scom.o