isa: Allow ISA-style drivers on modern systems

Several modern devices, such as PC/104 cards, are expected to run on
modern systems via an ISA bus interface. Since ISA is a legacy interface
for most modern architectures, ISA support should remain disabled in
general. Support for ISA-style drivers should be enabled on a per driver
basis.

To allow ISA-style drivers on modern systems, this patch introduces the
ISA_BUS_API and ISA_BUS Kconfig options. The ISA bus driver will now
build conditionally on the ISA_BUS_API Kconfig option, which defaults to
the legacy ISA Kconfig option. The ISA_BUS Kconfig option allows the
ISA_BUS_API Kconfig option to be selected on architectures which do not
enable ISA (e.g. X86_64).

The ISA_BUS Kconfig option is currently only implemented for X86
architectures. Other architectures may have their own ISA_BUS Kconfig
options added as required.

Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/arch/Kconfig b/arch/Kconfig
index d794384a0404d2e9b1d1e9c3f6a966ca877c647c..e9734796531f022cd188411e1bb14450922b74ef 100644 (file)
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -606,6 +606,9 @@ config HAVE_ARCH_HASH
          file which provides platform-specific implementations of some
          functions in <linux/hash.h> or fs/namei.c.
 
+config ISA_BUS_API
+       def_bool ISA
+
 #
 # ABI hall of shame
 #

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 0a7b885964baccd540f2c9e600dce014398bd987..d9a94da0c29fd72b048080681ab1660928a7d3f0 100644 (file)
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -2439,6 +2439,15 @@ config PCI_CNB20LE_QUIRK
 
 source "drivers/pci/Kconfig"
 
+config ISA_BUS
+       bool "ISA-style bus support on modern systems" if EXPERT
+       select ISA_BUS_API
+       help
+         Enables ISA-style drivers on modern systems. This is necessary to
+         support PC/104 devices on X86_64 platforms.
+
+         If unsure, say N.
+
 # x86_64 have no ISA slots, but can have ISA-style DMA.
 config ISA_DMA_API
        bool "ISA-style DMA support" if (X86_64 && EXPERT)

diff --git a/drivers/base/Makefile b/drivers/base/Makefile
index 6b2a84e7f2bece5643c2b68a17254067213b99ce..2609ba20b39622b1268323cd360171a3e545cbc1 100644 (file)
--- a/drivers/base/Makefile
+++ b/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-$(CONFIG_ISA_BUS_API)      += isa.o
 obj-$(CONFIG_FW_LOADER)        += firmware_class.o
 obj-$(CONFIG_NUMA)     += node.o
 obj-$(CONFIG_MEMORY_HOTPLUG_SPARSE) += memory.o

diff --git a/include/linux/isa.h b/include/linux/isa.h
index 5ab85281230b9dd688a3cad78217a42e932ab746..384ab9b7d79a85ba4c1ec2eb5d4f5d6c19db7e44 100644 (file)
--- a/include/linux/isa.h
+++ b/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_API
 int isa_register_driver(struct isa_driver *, unsigned int);
 void isa_unregister_driver(struct isa_driver *);
 #else