MIPS: improve checks for noncoherent DMA

Only one MIPS development board actually supports enabling/disabling DMA
coherency at runtime, so it's not a good idea to push the overhead of
checking that configuration setting onto every other supported target as
well.

Signed-off-by: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: John Crispin <blogic@openwrt.org>
Patchwork: http://patchwork.linux-mips.org/patch/5912/

1 files changed, 2 insertions, 0 deletions

diff --git a/arch/mips/mm/dma-default.c b/arch/mips/mm/dma-default.c
index 2e9418562258..44b6dff5aba2 100644
--- a/arch/mips/mm/dma-default.c
+++ b/arch/mips/mm/dma-default.c
@@ -23,6 +23,7 @@
 
 #include <dma-coherence.h>
 
+#ifdef CONFIG_DMA_MAYBE_COHERENT
 int coherentio = 0;     /* User defined DMA coherency from command line. */
 EXPORT_SYMBOL_GPL(coherentio);
 int hw_coherentio = 0;  /* Actual hardware supported DMA coherency setting. */
@@ -42,6 +43,7 @@ static int __init setnocoherentio(char *str)
         return 0;
 }
 early_param("nocoherentio", setnocoherentio);
+#endif
 
 static inline struct page *dma_addr_to_page(struct device *dev,
         dma_addr_t dma_addr)