x86, olpc: Add OLPC device-tree support

Make use of PROC_DEVICETREE to export the tree, and sparc's PROMTREE code to
call into OLPC's Open Firmware to build the tree.

v5: fix buglet with root node check (introduced in v4)

v4: address some minor style issues pointed out by Grant, and explicitly cast
    negative phandle checks to s32.

v3: rename olpc_prom to olpc_dt
  - rework Kconfig entries
  - drop devtree build hook from proc, instead adding a call to x86's
    paging_init (similarly to how sparc64 does it)
  - switch allocation from using slab to alloc_bootmem.  this allows
    the DT to be built earlier during boot (during setup_arch); the
    downside is that there are some 1200 bootmem reservations that are
    done during boot.  Not ideal..
  - add a helper olpc_ofw_is_installed function to test for the
    existence and successful detection of OLPC's OFW.

Signed-off-by: Andres Salomon <dilinger@queued.net>
LKML-Reference: <20101116220952.26526a80@queued.net>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/arch/x86/mm/init_32.c b/arch/x86/mm/init_32.c
index 0e969f9f401b..8c852e4af452 100644
--- a/arch/x86/mm/init_32.c
+++ b/arch/x86/mm/init_32.c
@@ -45,6 +45,7 @@
 #include <asm/bugs.h>
 #include <asm/tlb.h>
 #include <asm/tlbflush.h>
+#include <asm/olpc_ofw.h>
 #include <asm/pgalloc.h>
 #include <asm/sections.h>
 #include <asm/paravirt.h>
@@ -715,6 +716,7 @@ void __init paging_init(void)
         /*
          * NOTE: at this point the bootmem allocator is fully available.
          */
+        olpc_dt_build_devicetree();
         sparse_init();
         zone_sizes_init();
 }