sh: Provide FORCE_MAX_ZONEORDER.

Several platforms want to be able to do large physically contiguous
allocations (primarily nommu and video codecs on SH-Mobile), provide a
MAX_ORDER override for those cases.

Tested-by: Conrad Parker <conrad@metadecks.org>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>

1 files changed, 23 insertions, 0 deletions

diff --git a/arch/sh/mm/Kconfig b/arch/sh/mm/Kconfig
index b900d2cd18f7..2795618e4f07 100644
--- a/arch/sh/mm/Kconfig
+++ b/arch/sh/mm/Kconfig
@@ -21,6 +21,29 @@ config PAGE_OFFSET
         default "0x20000000" if MMU && SUPERH64
         default "0x00000000"
 
+config FORCE_MAX_ZONEORDER
+        int "Maximum zone order"
+        range 9 64 if PAGE_SIZE_16KB
+        default "9" if PAGE_SIZE_16KB
+        range 7 64 if PAGE_SIZE_64KB
+        default "7" if PAGE_SIZE_64KB
+        range 11 64
+        default "14" if !MMU
+        default "11"
+        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 11 means that the largest free memory block is 2^10 pages.
+
+          The page size is not necessarily 4KB. Keep this in mind when
+          choosing a value for this option.
+
 config MEMORY_START
         hex "Physical memory start address"
         default "0x08000000"