In response to new device tree code in the kernel, OLPC will start
using it for probing of certain devices. However, some firmware fixes
are needed to put the devicetree into a usable state.
Retain compatibility with old firmware by fixing up the device tree
at boot-time if it does not contain the new nodes/properties that
we need for probing. This is the same approach taken on PPC platforms.
Signed-off-by: Daniel Drake <dsd@laptop.org>
Link: http://lkml.kernel.org/r/1309019658-1712-2-git-send-email-dsd@laptop.org
Acked-by: Grant Likely <grant.likely@secretlab.ca>
Acked-by: Andres Salomon <dilinger@queued.net>
Cc: devicetree-discuss@lists.ozlabs.org
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
* 'x86-platform-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
x86: Introduce pci_map_biosrom()
x86, olpc: Use device tree for platform identification
Make OLPC fully depend on device tree, and use it to identify the OLPC
platform details. Some nodes are exposed as platform devices where we
plan to use device tree for device probing.
Signed-off-by: Daniel Drake <dsd@laptop.org>
Acked-by: Grant Likely <grant.likely@secretlab.ca>
LKML-Reference: <20110313151017.C255F9D401E@zog.reactivated.net>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
..similar to what sparc's prom_early_alloc does.
Signed-off-by: Andres Salomon <dilinger@queued.net>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
Calling alloc_bootmem() for tiny chunks of memory over and over is really
slow; on an XO-1, it caused the time between when the kernel started
booting and when the display came alive (post-lxfb probe) to increase
to 44s. This patch optimizes the prom_early_alloc function by
calling alloc_bootmem for 4k-sized blocks of memory, and handing out
chunks of that to callers. With this patch, the time between kernel load
and display initialization decreased to 23s. If there's a better way to
do this early in the boot process, please let me know.
(Note: increasing the chunk size to 16k didn't noticably affect boot time,
and wasted 9k.)
v4: clarify comment, requested by hpa
v3: fix wasted memory buglet found by Milton Miller, and style fix.
v2: reorder prom_early_alloc as suggested by Grant.
Signed-off-by: Andres Salomon <dilinger@queued.net>
LKML-Reference: <20101129153951.74202a84@queued.net>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
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>
Daniel Drake