NTB: Add support for AMD PCI-Express Non-Transparent Bridge

This adds support for AMD's PCI-Express Non-Transparent Bridge
(NTB) device on the Zeppelin platform. The driver connnects to the
standard NTB sub-system interface, with modification to add hooks
for power management in a separate patch. The AMD NTB device has 3
memory windows, 16 doorbell, 16 scratch-pad registers, and supports
up to 16 PCIe lanes running a Gen3 speeds.

Signed-off-by: Xiangliang Yu <[email protected]>
Reviewed-by: Allen Hubbe <[email protected]>
Signed-off-by: Jon Mason <[email protected]>

MAINTAINERS

@@ -7586,6 +7586,12 @@ W:	https://github.com/jonmason/ntb/wiki
 T:	git git://github.com/jonmason/ntb.git
 F:	drivers/ntb/hw/intel/
 
+NTB AMD DRIVER
+M:	Xiangliang Yu <[email protected]>
+L:	[email protected]
+S:	Supported
+F:	drivers/ntb/hw/amd/
+
 NTFS FILESYSTEM
 M:	Anton Altaparmakov <[email protected]>
 L:	[email protected]

drivers/ntb/hw/Kconfig

@@ -1 +1,2 @@
+source "drivers/ntb/hw/amd/Kconfig"
 source "drivers/ntb/hw/intel/Kconfig"

drivers/ntb/hw/Makefile

@@ -1 +1,2 @@
+obj-$(CONFIG_NTB_AMD)	+= amd/
 obj-$(CONFIG_NTB_INTEL)	+= intel/

drivers/ntb/hw/amd/Kconfig

@@ -0,0 +1,7 @@
+config NTB_AMD
+	tristate "AMD Non-Transparent Bridge support"
+	depends on X86_64
+	help
+	 This driver supports AMD NTB on capable Zeppelin hardware.
+
+	 If unsure, say N.

drivers/ntb/hw/amd/Makefile

@@ -0,0 +1 @@
+obj-$(CONFIG_NTB_AMD) += ntb_hw_amd.o