base: isa: Remove X86_32 dependency

Many motherboards utilize a LPC to ISA bridge in order to decode
ISA-style port-mapped I/O addresses. This is particularly true for
embedded motherboards supporting the PC/104 bus (a bus specification
derived from ISA).

These motherboards are now commonly running 64-bit x86 processors. The
X86_32 dependency should be removed from the ISA bus configuration
option in order to support these newer motherboards.

A new config option, CONFIG_ISA_BUS, is introduced to allow for the
compilation of the ISA bus driver independent of the CONFIG_ISA option.
Devices which communicate via ISA-compatible buses can now be supported
independent of the dependencies of the CONFIG_ISA option.
Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

arch/x86/Kconfig

@@ -2472,10 +2472,16 @@ config ISA_DMA_API
 	  Enables ISA-style DMA support for devices requiring such controllers.
 	  If unsure, say Y.
 
+config ISA_BUS
+	bool "ISA bus support"
+	help
+	  Enables ISA bus support for devices requiring such controllers.
+
 if X86_32
 
 config ISA
 	bool "ISA support"
+	depends on ISA_BUS
 	---help---
 	  Find out whether you have ISA slots on your motherboard.  ISA is the
 	  name of a bus system, i.e. the way the CPU talks to the other stuff

drivers/base/Makefile

@@ -10,7 +10,7 @@ obj-$(CONFIG_DMA_CMA) += dma-contiguous.o
 obj-y			+= power/
 obj-$(CONFIG_HAS_DMA)	+= dma-mapping.o
 obj-$(CONFIG_HAVE_GENERIC_DMA_COHERENT) += dma-coherent.o
-obj-$(CONFIG_ISA)	+= isa.o
+obj-$(CONFIG_ISA_BUS)	+= isa.o
 obj-$(CONFIG_FW_LOADER)	+= firmware_class.o
 obj-$(CONFIG_NUMA)	+= node.o
 obj-$(CONFIG_MEMORY_HOTPLUG_SPARSE) += memory.o

include/linux/isa.h

@@ -22,7 +22,7 @@ struct isa_driver {
 
 #define to_isa_driver(x) container_of((x), struct isa_driver, driver)
 
-#ifdef CONFIG_ISA
+#ifdef CONFIG_ISA_BUS
 int isa_register_driver(struct isa_driver *, unsigned int);
 void isa_unregister_driver(struct isa_driver *);
 #else