nios2: add dma_alloc_coherent

This function return cache-line aligned allocation which is mapped
to uncached io region.

Signed-off-by: Thomas Chou <thomas@wytron.com.tw>
Signed-off-by: Scott McNutt <smcnutt@psyent.com>

diff --git a/arch/nios2/include/asm/dma-mapping.h b/arch/nios2/include/asm/dma-mapping.h
new file mode 100644 (file)
index 0000000..1350e3b
--- /dev/null
+++ b/arch/nios2/include/asm/dma-mapping.h
@@ -0,0 +1,23 @@
+#ifndef __ASM_NIOS2_DMA_MAPPING_H
+#define __ASM_NIOS2_DMA_MAPPING_H
+
+/* dma_alloc_coherent() return cache-line aligned allocation which is mapped
+ * to uncached io region.
+ *
+ * IO_REGION_BASE should be defined in board config header file
+ *   0x80000000 for nommu, 0xe0000000 for mmu
+ */
+
+static inline void *dma_alloc_coherent(size_t len, unsigned long *handle)
+{
+       void *addr = malloc(len + CONFIG_SYS_DCACHELINE_SIZE);
+       if (!addr)
+               return 0;
+       flush_dcache((unsigned long)addr, len + CONFIG_SYS_DCACHELINE_SIZE);
+       *handle = ((unsigned long)addr +
+                  (CONFIG_SYS_DCACHELINE_SIZE - 1)) &
+               ~(CONFIG_SYS_DCACHELINE_SIZE - 1) & ~(IO_REGION_BASE);
+       return (void *)(*handle | IO_REGION_BASE);
+}
+
+#endif /* __ASM_NIOS2_DMA_MAPPING_H */