+ edac-cpc925-mc-platform-device-setup.patch added to -mm tree
qingtao.cao at windriver.com
Thu Apr 16 13:40:58 EST 2009
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, akpm at 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
>>>> +++ 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
>>> 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
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.
>> 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.
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