Le 20/02/2018 à 17:14, Jonathan Neuschäfer a écrit :
This patchset adds support for DISCONTIGMEM on 32-bit PowerPC. This is required to properly support the Nintendo Wii's memory layout, in which there are two blocks of RAM and MMIO in the middle. Previously, this memory layout was handled by code that joins the two RAM blocks into one, reserves the MMIO hole, and permits allocations of reserved memory in ioremap. This hack didn't work with resource-based allocation (as used for example in the GPIO driver for Wii[1]), however. After this patchset, users of the Wii can either select CONFIG_FLATMEM to get the old behaviour, or CONFIG_DISCONTIGMEM to get the new behaviour.
My question might me stupid, as I don't know PCC64 in deep, but when looking at page_is_ram() in arch/powerpc/mm/mem.c, I have the feeling the PPC64 implements ram by blocks. Isn't it what you are trying to achieve ? Wouldn't it be feasible to map to what's done in PPC64 for PPC32 ?
Christophe
Some parts of this patchset are probably not ideal (I'm thinking of my implementation of pfn_to_nid here), and will require some discussion/ changes. [1]: https://www.spinics.net/lists/devicetree/msg213956.html Jonathan Neuschäfer (6): powerpc/mm/32: Use pfn_valid to check if pointer is in RAM powerpc: numa: Fix overshift on PPC32 powerpc: numa: Use the right #ifdef guards around functions powerpc: numa: Restrict fake NUMA enulation to CONFIG_NUMA systems powerpc: Implement DISCONTIGMEM and allow selection on PPC32 powerpc: wii: Don't rely on reserved memory hack if DISCONTIGMEM is set arch/powerpc/Kconfig | 5 ++++- arch/powerpc/include/asm/mmzone.h | 21 +++++++++++++++++++++ arch/powerpc/mm/numa.c | 18 +++++++++++++++--- arch/powerpc/mm/pgtable_32.c | 2 +- arch/powerpc/platforms/embedded6xx/wii.c | 10 +++++++--- 5 files changed, 48 insertions(+), 8 deletions(-)
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