[PATCH v8 16/16] ARM: LPAE: Add the Kconfig entries

On Thu, Nov 10, 2011 at 10:57:37PM +0000, Russell King - ARM Linux wrote:

On Mon, Nov 07, 2011 at 04:16:58PM +0000, Catalin Marinas wrote:

quoted

+config ARCH_PHYS_ADDR_T_64BIT
+	def_bool ARM_LPAE
+
+config ARCH_DMA_ADDR_T_64BIT
+	def_bool ARM_LPAE
+

I still say this shouldn't depend on the host page table format.  LPAE
itself has nothing to do with whether 64-bit DMA addresses are supported
by the system.

So we could change this to:

config ARCH_DMA_ADDR_T_64BIT
	depends on ARM_LPAE

and let platforms select it.

The x86 approach is to have another HIGHMEM64G config option for
systems with more than 4GB of RAM and ARCH_DMA_ADDR_T_64BIT is selected
automatically. But this comes under the assumption that there is a 1:1
mapping between phys and bus addresses.

-- 
Catalin