ARM: disable virt_to_bus/virt_to_bus almost everywhere

We are getting a number of warnings about the use of the deprecated
bus_to_virt function in drivers using the ARM ISA DMA API:

drivers/parport/parport_pc.c: In function 'parport_pc_fifo_write_block_dma':
drivers/parport/parport_pc.c:622:3: warning: 'bus_to_virt' is deprecated
(declared at arch/arm/include/asm/memory.h:253) [-Wdeprecated-declarations]

This is only because that function gets used by the inline
set_dma_addr() helper. We know that any driver for the ISA DMA API
is correctly using the DMA addresses, so we can change this
to use the __bus_to_virt() function instead, which does not warn.

After this, there are no remaining drivers that are used on
any defconfigs on ARM using virt_to_bus or bus_to_virt, with
the exception of the OSS sound driver. That driver is only used
on RiscPC, NetWinder and Shark, so we can set ARCH_NO_VIRT_TO_BUS
on all other platforms and hide the deprecated functions, which
is far more effective than marking them as deprecated, in order
to avoid any new users of that code.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: Russell King <linux@arm.linux.org.uk>

arch/arm/Kconfig

@@ -1450,6 +1450,10 @@ config ISA_DMA
 	bool
 	select ISA_DMA_API
 
+config ARCH_NO_VIRT_TO_BUS
+	def_bool y
+	depends on !ARCH_RPC && !ARCH_NETWINDER && !ARCH_SHARK
+
 # Select ISA DMA interface
 config ISA_DMA_API
 	bool

arch/arm/configs/shark_defconfig

@@ -73,7 +73,6 @@ CONFIG_PARTITION_ADVANCED=y
 CONFIG_NLS_CODEPAGE_437=m
 CONFIG_NLS_CODEPAGE_850=m
 CONFIG_NLS_ISO8859_1=m
-# CONFIG_ENABLE_WARN_DEPRECATED is not set
 # CONFIG_ENABLE_MUST_CHECK is not set
 CONFIG_DEBUG_KERNEL=y
 # CONFIG_SCHED_DEBUG is not set

arch/arm/include/asm/dma.h

@@ -105,7 +105,7 @@ extern void set_dma_sg(unsigned int chan, struct scatterlist *sg, int nr_sg);
  */
 extern void __set_dma_addr(unsigned int chan, void *addr);
 #define set_dma_addr(chan, addr)				\
-	__set_dma_addr(chan, bus_to_virt(addr))
+	__set_dma_addr(chan, (void *)__bus_to_virt(addr))
 
 /* Set the DMA byte count for this channel
  *

arch/arm/include/asm/memory.h

@@ -245,6 +245,7 @@ static inline void *phys_to_virt(phys_addr_t x)
 #define __bus_to_pfn(x)	__phys_to_pfn(x)
 #endif
 
+#ifdef CONFIG_VIRT_TO_BUS
 static inline __deprecated unsigned long virt_to_bus(void *x)
 {
 	return __virt_to_bus((unsigned long)x);
@@ -254,6 +255,7 @@ static inline __deprecated void *bus_to_virt(unsigned long x)
 {
 	return (void *)__bus_to_virt(x);
 }
+#endif
 
 /*
  * Conversion between a struct page and a physical address.