MIPS: Extend DMA_MAYBE_COHERENT logic to DMA_NONCOHERENT use

Setting DMA_MAYBE_COHERENT gives a platform the opportunity to select
use of cache ops at boot.
Signed-off-by: Manuel Lauss <manuel.lauss@gmail.com>
Cc: Linux-MIPS <linux-mips@linux-mips.org>
Patchwork: https://patchwork.linux-mips.org/patch/6575/Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

arch/mips/include/asm/io.h

@@ -584,7 +584,7 @@ static inline void memcpy_toio(volatile void __iomem *dst, const void *src, int
  *
  * This API used to be exported; it now is for arch code internal use only.
  */
-#ifdef CONFIG_DMA_NONCOHERENT
+#if defined(CONFIG_DMA_NONCOHERENT) || defined(CONFIG_DMA_MAYBE_COHERENT)
 
 extern void (*_dma_cache_wback_inv)(unsigned long start, unsigned long size);
 extern void (*_dma_cache_wback)(unsigned long start, unsigned long size);
@@ -603,7 +603,7 @@ extern void (*_dma_cache_inv)(unsigned long start, unsigned long size);
 #define dma_cache_inv(start,size)	\
 	do { (void) (start); (void) (size); } while (0)
 
-#endif /* CONFIG_DMA_NONCOHERENT */
+#endif /* CONFIG_DMA_NONCOHERENT || CONFIG_DMA_MAYBE_COHERENT */
 
 /*
  * Read a 32-bit register that requires a 64-bit read cycle on the bus.

arch/mips/mm/c-r4k.c

@@ -673,7 +673,7 @@ static void r4k_flush_icache_range(unsigned long start, unsigned long end)
 	instruction_hazard();
 }
 
-#ifdef CONFIG_DMA_NONCOHERENT
+#if defined(CONFIG_DMA_NONCOHERENT) || defined(CONFIG_DMA_MAYBE_COHERENT)
 
 static void r4k_dma_cache_wback_inv(unsigned long addr, unsigned long size)
 {
@@ -744,7 +744,7 @@ static void r4k_dma_cache_inv(unsigned long addr, unsigned long size)
 	bc_inv(addr, size);
 	__sync();
 }
-#endif /* CONFIG_DMA_NONCOHERENT */
+#endif /* CONFIG_DMA_NONCOHERENT || CONFIG_DMA_MAYBE_COHERENT */
 
 /*
  * While we're protected against bad userland addresses we don't care
@@ -1559,7 +1559,7 @@ void r4k_cache_init(void)
 	flush_icache_range	= r4k_flush_icache_range;
 	local_flush_icache_range	= local_r4k_flush_icache_range;
 
-#if defined(CONFIG_DMA_NONCOHERENT)
+#if defined(CONFIG_DMA_NONCOHERENT) || defined(CONFIG_DMA_MAYBE_COHERENT)
 	if (coherentio) {
 		_dma_cache_wback_inv	= (void *)cache_noop;
 		_dma_cache_wback	= (void *)cache_noop;

arch/mips/mm/cache.c

@@ -49,7 +49,7 @@ EXPORT_SYMBOL_GPL(local_flush_data_cache_page);
 EXPORT_SYMBOL(flush_data_cache_page);
 EXPORT_SYMBOL(flush_icache_all);
 
-#ifdef CONFIG_DMA_NONCOHERENT
+#if defined(CONFIG_DMA_NONCOHERENT) || defined(CONFIG_DMA_MAYBE_COHERENT)
 
 /* DMA cache operations. */
 void (*_dma_cache_wback_inv)(unsigned long start, unsigned long size);
@@ -58,7 +58,7 @@ void (*_dma_cache_inv)(unsigned long start, unsigned long size);
 
 EXPORT_SYMBOL(_dma_cache_wback_inv);
 
-#endif /* CONFIG_DMA_NONCOHERENT */
+#endif /* CONFIG_DMA_NONCOHERENT || CONFIG_DMA_MAYBE_COHERENT */
 
 /*
  * We could optimize the case where the cache argument is not BCACHE but