C6X: memory management and DMA support

Original port to early 2.6 kernel using TI COFF toolchain.
Brought up to date by Mark Salter <msalter@redhat.com>

The C6X architecture currently lacks an MMU so memory management is relatively
simple. There is no bus snooping between L2 and main memory but coherent DMA
memory is supported by making regions of main memory uncached. If such a region
is desired, it can be specified on the commandline with a "memdma=" argument.

Signed-off-by: Aurelien Jacquiot <a-jacquiot@ti.com>
Signed-off-by: Mark Salter <msalter@redhat.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>

1 files changed, 91 insertions, 0 deletions

diff --git a/arch/c6x/include/asm/dma-mapping.h b/arch/c6x/include/asm/dma-mapping.h
new file mode 100644
index 00000000000..03579fd99db
--- /dev/null
+++ b/arch/c6x/include/asm/dma-mapping.h
@@ -0,0 +1,91 @@
+/*
+ *  Port on Texas Instruments TMS320C6x architecture
+ *
+ *  Copyright (C) 2004, 2009, 2010, 2011 Texas Instruments Incorporated
+ *  Author: Aurelien Jacquiot <aurelien.jacquiot@ti.com>
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License version 2 as
+ *  published by the Free Software Foundation.
+ *
+ */
+#ifndef _ASM_C6X_DMA_MAPPING_H
+#define _ASM_C6X_DMA_MAPPING_H
+
+#include <linux/dma-debug.h>
+#include <asm-generic/dma-coherent.h>
+
+#define dma_supported(d, m)	1
+
+static inline int dma_set_mask(struct device *dev, u64 dma_mask)
+{
+	if (!dev->dma_mask || !dma_supported(dev, dma_mask))
+		return -EIO;
+
+	*dev->dma_mask = dma_mask;
+
+	return 0;
+}
+
+/*
+ * DMA errors are defined by all-bits-set in the DMA address.
+ */
+static inline int dma_mapping_error(struct device *dev, dma_addr_t dma_addr)
+{
+	return dma_addr == ~0;
+}
+
+extern dma_addr_t dma_map_single(struct device *dev, void *cpu_addr,
+				 size_t size, enum dma_data_direction dir);
+
+extern void dma_unmap_single(struct device *dev, dma_addr_t handle,
+			     size_t size, enum dma_data_direction dir);
+
+extern int dma_map_sg(struct device *dev, struct scatterlist *sglist,
+		      int nents, enum dma_data_direction direction);
+
+extern void dma_unmap_sg(struct device *dev, struct scatterlist *sglist,
+			 int nents, enum dma_data_direction direction);
+
+static inline dma_addr_t dma_map_page(struct device *dev, struct page *page,
+				      unsigned long offset, size_t size,
+				      enum dma_data_direction dir)
+{
+	dma_addr_t handle;
+
+	handle = dma_map_single(dev, page_address(page) + offset, size, dir);
+
+	debug_dma_map_page(dev, page, offset, size, dir, handle, false);
+
+	return handle;
+}
+
+static inline void dma_unmap_page(struct device *dev, dma_addr_t handle,
+		size_t size, enum dma_data_direction dir)
+{
+	dma_unmap_single(dev, handle, size, dir);
+
+	debug_dma_unmap_page(dev, handle, size, dir, false);
+}
+
+extern void dma_sync_single_for_cpu(struct device *dev, dma_addr_t handle,
+				    size_t size, enum dma_data_direction dir);
+
+extern void dma_sync_single_for_device(struct device *dev, dma_addr_t handle,
+				       size_t size,
+				       enum dma_data_direction dir);
+
+extern void dma_sync_sg_for_cpu(struct device *dev, struct scatterlist *sg,
+				int nents, enum dma_data_direction dir);
+
+extern void dma_sync_sg_for_device(struct device *dev, struct scatterlist *sg,
+				   int nents, enum dma_data_direction dir);
+
+extern void coherent_mem_init(u32 start, u32 size);
+extern void *dma_alloc_coherent(struct device *, size_t, dma_addr_t *, gfp_t);
+extern void dma_free_coherent(struct device *, size_t, void *, dma_addr_t);
+
+#define dma_alloc_noncoherent(d, s, h, f) dma_alloc_coherent((d), (s), (h), (f))
+#define dma_free_noncoherent(d, s, v, h)  dma_free_coherent((d), (s), (v), (h))
+
+#endif	/* _ASM_C6X_DMA_MAPPING_H */