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, 6 insertions, 0 deletions

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index e330da21b84f..ef34031a8339 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -2049,11 +2049,17 @@ config OLPC_OPENFIRMWARE
         bool "Support for OLPC's Open Firmware"
         depends on !X86_64 && !X86_PAE
         default n
+        select OF
         help
           This option adds support for the implementation of Open Firmware
           that is used on the OLPC XO-1 Children's Machine.
           If unsure, say N here.
 
+config OLPC_OPENFIRMWARE_DT
+        bool
+        default y if OLPC_OPENFIRMWARE && PROC_DEVICETREE
+        select OF_PROMTREE
+
 endif # X86_32
 
 config AMD_NB