Michael Ellerman wrote:
On Thu, 2009-04-16 at 09:57 +0800, Harry Ciao wrote:
Kumar Gala wrote:
On Apr 15, 2009, at 5:27 PM, a...@linux-foundation.org wrote:
arch/powerpc/kernel/prom_init.c | 33 +++++++++++++
arch/powerpc/platforms/maple/setup.c | 59 +++++++++++++++++++++++++
2 files changed, 92 insertions(+)
diff -puN
arch/powerpc/kernel/prom_init.c~edac-cpc925-mc-platform-device-setup
arch/powerpc/kernel/prom_init.c
---
a/arch/powerpc/kernel/prom_init.c~edac-cpc925-mc-platform-device-setup
+++ a/arch/powerpc/kernel/prom_init.c
@@ -1947,8 +1947,40 @@ static void __init fixup_device_tree_map
prom_setprop(isa, name, "ranges",
isa_ranges, sizeof(isa_ranges));
}
+
+#define CPC925_MC_START 0xf8000000
+#define CPC925_MC_LENGTH 0x1000000
+/* The values for memory-controller don't have right number of cells */
+static void __init fixup_device_tree_maple_memory_controller(void)
+{
I don't see why this cant be part of the existing
fixup_device_tree_maple().
I also find it odd we don't ensure we are running on a maple before we
apply this fixup.
Hi Kumar,
Thanks a lot for your concern.
This newly added fixup for memory controller on Maple will be placed
right after fixup_device_tree_maple(), both of them will be controlled
by CONFIG_PPC_MAPLE, so there is no worry that it will be applied
against anything other than Maple.
Hi Harry,
We regularly build a single kernel with multiple platforms enabled, so
just having it controlled by a CONFIG symbol is not sufficient. Someone
might build a kernel for MAPLE & PSERIES & ISERIES & CELL, so the maple
fixup needs to be careful it doesn't break the other platforms.
The existing maple fixup doesn't check if it's on a maple either, but it
is a bit more discerning about what it finds before it fixes things up.
Your code already checks that "reg" is 8 bytes long to start with, I
think if it also checks that #address-cells and #size-cells are == 2,
then it's pretty safe. Because at that point we know we have a node with
the right name, the reg property has a known value, and reg is short WRT
#cells.
Many thanks Michael!
That makes a lot of sense to me :) I will integrate the check if both
its parent #address-cells and #size-cells equal to 2 before fixing
anything up. The fact that the reg length == 8 bytes whereas parent's
cells are 2 validate our fixup is necessary.
Best regards,
Harry
Meanwhile, it aims at fixup bad cell numbers for the memory controller,
whereas the original fixup_device_tree_maple() aiming at fixing up the
ISA controller on HT channel, we'd better separate them in different
function IMHO.
I think I agree it's better as a separate routine. We could have a
firmware that doesn't need the original maple fixup (and so exits from
that routine early) but does need this one.
cheers
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