[patch] Introduce CONFIG_HAS_DMA.

[Heiko Carstens]

From: Heiko Carstens <heiko.carstens@xxxxxxxxxx>

Architectures that don't support DMA can say so by adding a
config NO_DMA to their Kconfig file. This will prevent compilation
of some dma specific driver code. Also dma-mapping-broken.h isn't
needed anymore on at least s390.
This avoids compilation and linking of otherwise dead/broken code.

Signed-off-by: Heiko Carstens <heiko.carstens@xxxxxxxxxx>
---

Other architectures that include dma-mapping-broken.h are
arm26, h8300, m68k, m68knommu and v850. If these could be converted
as well we could get rid of the header file.

 arch/s390/Kconfig              |    3 +++
 drivers/base/Makefile          |    4 ++--
 include/asm-s390/dma-mapping.h |    2 --
 lib/Kconfig                    |    5 +++++
 4 files changed, 10 insertions(+), 4 deletions(-)

Index: linux-2.6/arch/s390/Kconfig
===================================================================
--- linux-2.6.orig/arch/s390/Kconfig
+++ linux-2.6/arch/s390/Kconfig
@@ -44,6 +44,9 @@ config GENERIC_TIME
 config NO_IOMEM
 	def_bool y
 
+config NO_DMA
+	def_bool y
+
 mainmenu "Linux Kernel Configuration"
 
 config S390
Index: linux-2.6/drivers/base/Makefile
===================================================================
--- linux-2.6.orig/drivers/base/Makefile
+++ linux-2.6/drivers/base/Makefile
@@ -2,10 +2,10 @@
 
 obj-y			:= core.o sys.o bus.o dd.o \
 			   driver.o class.o platform.o \
-			   cpu.o firmware.o init.o map.o dmapool.o \
-			   dma-mapping.o devres.o \
+			   cpu.o firmware.o init.o map.o devres.o \
 			   attribute_container.o transport_class.o
 obj-y			+= power/
+obj-$(CONFIG_HAS_DMA)	+= dma-mapping.o dmapool.o
 obj-$(CONFIG_ISA)	+= isa.o
 obj-$(CONFIG_FW_LOADER)	+= firmware_class.o
 obj-$(CONFIG_NUMA)	+= node.o
Index: linux-2.6/include/asm-s390/dma-mapping.h
===================================================================
--- linux-2.6.orig/include/asm-s390/dma-mapping.h
+++ linux-2.6/include/asm-s390/dma-mapping.h
@@ -9,6 +9,4 @@
 #ifndef _ASM_DMA_MAPPING_H
 #define _ASM_DMA_MAPPING_H
 
-#include <asm-generic/dma-mapping-broken.h>
-
 #endif /* _ASM_DMA_MAPPING_H */
Index: linux-2.6/lib/Kconfig
===================================================================
--- linux-2.6.orig/lib/Kconfig
+++ linux-2.6/lib/Kconfig
@@ -111,4 +111,9 @@ config HAS_IOPORT
 	depends on HAS_IOMEM && !NO_IOPORT
 	default y
 
+config HAS_DMA
+	boolean
+	depends on !NO_DMA
+	default y
+
 endmenu

-- 
Heiko Carstens
Linux on System z Development

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