x86: allow CONFIG_ISA_DMA_API to be disabled

Not all 64-bit systems require ISA-style DMA, so allow it to be
configurable.  x86 utilizes the generic ISA DMA allocator from
kernel/dma.c, so require it only when CONFIG_ISA_DMA_API is enabled.

Disabling CONFIG_ISA_DMA_API is dependent on x86_64 since those machines
do not have ISA slots and benefit the most from disabling the option (and
on CONFIG_EXPERT as required by H.  Peter Anvin).

When disabled, this also avoids declaring claim_dma_lock(),
release_dma_lock(), request_dma(), and free_dma() since those interfaces
will no longer be provided.

Signed-off-by: David Rientjes <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: "H. Peter Anvin" <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Bjorn Helgaas <[email protected]>
Cc: Russell King <[email protected]>
Cc: "Luck, Tony" <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

0 files changed, 0 insertions, 0 deletions