powerpc/powernv/pci: Return failure for some uses of dma_set_mask()
Commit 8e3f1b1d ("powerpc/powernv/pci: Enable 64-bit devices to access >4GB DMA space") introduced the ability for PCI device drivers to request a DMA mask between 64 and 32 bits and actually get a mask greater than 32-bits. However currently if certain machine configuration dependent conditions are not meet the code silently falls back to a 32-bit mask. This makes it hard for device drivers to detect which mask they actually got. Instead we should return an error when the request could not be fulfilled which allows drivers to either fallback or implement other workarounds as documented in DMA-API-HOWTO.txt. Signed-off-by:Alistair Popple <alistair@popple.id.au> Acked-by:
Russell Currey <ruscur@russell.cc> Signed-off-by:
Michael Ellerman <mpe@ellerman.id.au>
parent
65c5ec11
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