sparc64: Add FORCE_MAX_ZONEORDER and default to 13

This change allows ATU (new IOMMU) in SPARC systems to request
large (32M) contiguous memory during boot for creating IOTSB backing
store.
Signed-off-by: Dave Kleikamp <dave.kleikamp@oracle.com>
Signed-off-by: Tushar Dave <tushar.n.dave@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

arch/sparc/Kconfig

@@ -89,6 +89,10 @@ config ARCH_DEFCONFIG
 config ARCH_PROC_KCORE_TEXT
 	def_bool y
 
+config ARCH_ATU
+	bool
+	default y if SPARC64
+
 config IOMMU_HELPER
 	bool
 	default y if SPARC64
@@ -304,6 +308,20 @@ config ARCH_SPARSEMEM_ENABLE
 config ARCH_SPARSEMEM_DEFAULT
 	def_bool y if SPARC64
 
+config FORCE_MAX_ZONEORDER
+	int "Maximum zone order"
+	default "13"
+	help
+	  The kernel memory allocator divides physically contiguous memory
+	  blocks into "zones", where each zone is a power of two number of
+	  pages.  This option selects the largest power of two that the kernel
+	  keeps in the memory allocator.  If you need to allocate very large
+	  blocks of physically contiguous memory, then you may need to
+	  increase this value.
+
+	  This config option is actually maximum order plus one. For example,
+	  a value of 13 means that the largest free memory block is 2^12 pages.
+
 source "mm/Kconfig"
 
 if SPARC64