powerpc/powernv: Allocate PE# in reverse order
PE number for one particular PE can be allocated dynamically or reserved according to the consumed M64 (64-bits prefetchable) segments of the PE. The M64 segment can't be remapped to arbitrary PE, meaning the PE number is determined according to the index of the consumed M64 segment. As below figure shows, M64 resource grows from low to high end, meaning the PE (number) reserved according to M64 segment grows from low to high end as well, so does the dynamically allocated PE number. It will lead to conflict: PE number (M64 segment) reserved by dynamic allocation is required by hot added PCI adapter at later point. It fails the PCI hotplug because of the PE number can't be reserved based on the index of the consumed M64 segment. +---+---+---+---+---+--------------------------------+-----+ | 0 | 1 | 2 | 3 | 4 | ....... | 255 | +---+---+---+---+---+--------------------------------+-----+ PE number for dynamic allocation -----------------> PE number reserved for M64 segment -----------------> To resolve above conflicts, this forces the PE number to be allocated dynamically in reverse order. With this patch applied, the PE numbers are reserved in ascending order, but allocated dynamically in reverse order. Signed-off-by:Gavin Shan <gwshan@linux.vnet.ibm.com> Signed-off-by:
Michael Ellerman <mpe@ellerman.id.au>
parent
c127562a
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