xtensa: reimplement DMA API using common helpers

- keep existing functionality: don't handle attributes, don't support
  high memory;
- implement scatterlist primitives (map/unmap/sync);
- enable DMA API debug.

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>

1 files changed, 173 insertions, 30 deletions

diff --git a/arch/xtensa/kernel/pci-dma.c b/arch/xtensa/kernel/pci-dma.c
index e8b76b8..fb75ebf 100644
--- a/arch/xtensa/kernel/pci-dma.c
+++ b/arch/xtensa/kernel/pci-dma.c
@@ -1,6 +1,4 @@
 /*
- * arch/xtensa/kernel/pci-dma.c
- *
  * DMA coherent memory allocation.
  *
  * This program is free software; you can redistribute  it and/or modify it
@@ -9,6 +7,7 @@
  * option) any later version.
  *
  * Copyright (C) 2002 - 2005 Tensilica Inc.
+ * Copyright (C) 2015 Cadence Design Systems Inc.
  *
  * Based on version for i386.
  *
@@ -25,13 +24,107 @@
 #include <asm/io.h>
 #include <asm/cacheflush.h>
 
+void dma_cache_sync(struct device *dev, void *vaddr, size_t size,
+		    enum dma_data_direction dir)
+{
+	switch (dir) {
+	case DMA_BIDIRECTIONAL:
+		__flush_invalidate_dcache_range((unsigned long)vaddr, size);
+		break;
+
+	case DMA_FROM_DEVICE:
+		__invalidate_dcache_range((unsigned long)vaddr, size);
+		break;
+
+	case DMA_TO_DEVICE:
+		__flush_dcache_range((unsigned long)vaddr, size);
+		break;
+
+	case DMA_NONE:
+		BUG();
+		break;
+	}
+}
+EXPORT_SYMBOL(dma_cache_sync);
+
+static void xtensa_sync_single_for_cpu(struct device *dev,
+				       dma_addr_t dma_handle, size_t size,
+				       enum dma_data_direction dir)
+{
+	void *vaddr;
+
+	switch (dir) {
+	case DMA_BIDIRECTIONAL:
+	case DMA_FROM_DEVICE:
+		vaddr = bus_to_virt(dma_handle);
+		__invalidate_dcache_range((unsigned long)vaddr, size);
+		break;
+
+	case DMA_NONE:
+		BUG();
+		break;
+
+	default:
+		break;
+	}
+}
+
+static void xtensa_sync_single_for_device(struct device *dev,
+					  dma_addr_t dma_handle, size_t size,
+					  enum dma_data_direction dir)
+{
+	void *vaddr;
+
+	switch (dir) {
+	case DMA_BIDIRECTIONAL:
+	case DMA_TO_DEVICE:
+		vaddr = bus_to_virt(dma_handle);
+		__flush_dcache_range((unsigned long)vaddr, size);
+		break;
+
+	case DMA_NONE:
+		BUG();
+		break;
+
+	default:
+		break;
+	}
+}
+
+static void xtensa_sync_sg_for_cpu(struct device *dev,
+				   struct scatterlist *sg, int nents,
+				   enum dma_data_direction dir)
+{
+	struct scatterlist *s;
+	int i;
+
+	for_each_sg(sg, s, nents, i) {
+		xtensa_sync_single_for_cpu(dev, sg_dma_address(s),
+					   sg_dma_len(s), dir);
+	}
+}
+
+static void xtensa_sync_sg_for_device(struct device *dev,
+				      struct scatterlist *sg, int nents,
+				      enum dma_data_direction dir)
+{
+	struct scatterlist *s;
+	int i;
+
+	for_each_sg(sg, s, nents, i) {
+		xtensa_sync_single_for_device(dev, sg_dma_address(s),
+					      sg_dma_len(s), dir);
+	}
+}
+
 /*
  * Note: We assume that the full memory space is always mapped to 'kseg'
  *	 Otherwise we have to use page attributes (not implemented).
  */
 
-void *
-dma_alloc_coherent(struct device *dev,size_t size,dma_addr_t *handle,gfp_t flag)
+static void *xtensa_dma_alloc(struct device *dev, size_t size,
+			      dma_addr_t *handle, gfp_t flag,
+			      struct dma_attrs *attrs)
 {
 	unsigned long ret;
 	unsigned long uncached = 0;
@@ -52,20 +145,15 @@ dma_alloc_coherent(struct device *dev,size_t size,dma_addr_t *handle,gfp_t flag)
 	BUG_ON(ret < XCHAL_KSEG_CACHED_VADDR ||
 	       ret > XCHAL_KSEG_CACHED_VADDR + XCHAL_KSEG_SIZE - 1);
 
+	uncached = ret + XCHAL_KSEG_BYPASS_VADDR - XCHAL_KSEG_CACHED_VADDR;
+	*handle = virt_to_bus((void *)ret);
+	__invalidate_dcache_range(ret, size);
 
-	if (ret != 0) {
-		memset((void*) ret, 0, size);
-		uncached = ret+XCHAL_KSEG_BYPASS_VADDR-XCHAL_KSEG_CACHED_VADDR;
-		*handle = virt_to_bus((void*)ret);
-		__flush_invalidate_dcache_range(ret, size);
-	}
-
-	return (void*)uncached;
+	return (void *)uncached;
 }
-EXPORT_SYMBOL(dma_alloc_coherent);
 
-void dma_free_coherent(struct device *hwdev, size_t size,
-			 void *vaddr, dma_addr_t dma_handle)
+static void xtensa_dma_free(struct device *hwdev, size_t size, void *vaddr,
+			    dma_addr_t dma_handle, struct dma_attrs *attrs)
 {
 	unsigned long addr = (unsigned long)vaddr +
 		XCHAL_KSEG_CACHED_VADDR - XCHAL_KSEG_BYPASS_VADDR;
@@ -75,24 +163,79 @@ void dma_free_coherent(struct device *hwdev, size_t size,
 
 	free_pages(addr, get_order(size));
 }
-EXPORT_SYMBOL(dma_free_coherent);
 
+static dma_addr_t xtensa_map_page(struct device *dev, struct page *page,
+				  unsigned long offset, size_t size,
+				  enum dma_data_direction dir,
+				  struct dma_attrs *attrs)
+{
+	dma_addr_t dma_handle = page_to_phys(page) + offset;
+
+	BUG_ON(PageHighMem(page));
+	xtensa_sync_single_for_device(dev, dma_handle, size, dir);
+	return dma_handle;
+}
 
-void consistent_sync(void *vaddr, size_t size, int direction)
+static void xtensa_unmap_page(struct device *dev, dma_addr_t dma_handle,
+			      size_t size, enum dma_data_direction dir,
+			      struct dma_attrs *attrs)
 {
-	switch (direction) {
-	case PCI_DMA_NONE:
-		BUG();
-	case PCI_DMA_FROMDEVICE:        /* invalidate only */
-		__invalidate_dcache_range((unsigned long)vaddr,
-				          (unsigned long)size);
-		break;
+	xtensa_sync_single_for_cpu(dev, dma_handle, size, dir);
+}
 
-	case PCI_DMA_TODEVICE:          /* writeback only */
-	case PCI_DMA_BIDIRECTIONAL:     /* writeback and invalidate */
-		__flush_invalidate_dcache_range((unsigned long)vaddr,
-				    		(unsigned long)size);
-		break;
+static int xtensa_map_sg(struct device *dev, struct scatterlist *sg,
+			 int nents, enum dma_data_direction dir,
+			 struct dma_attrs *attrs)
+{
+	struct scatterlist *s;
+	int i;
+
+	for_each_sg(sg, s, nents, i) {
+		s->dma_address = xtensa_map_page(dev, sg_page(s), s->offset,
+						 s->length, dir, attrs);
+	}
+	return nents;
+}
+
+static void xtensa_unmap_sg(struct device *dev,
+			    struct scatterlist *sg, int nents,
+			    enum dma_data_direction dir,
+			    struct dma_attrs *attrs)
+{
+	struct scatterlist *s;
+	int i;
+
+	for_each_sg(sg, s, nents, i) {
+		xtensa_unmap_page(dev, sg_dma_address(s),
+				  sg_dma_len(s), dir, attrs);
 	}
 }
-EXPORT_SYMBOL(consistent_sync);
+
+int xtensa_dma_mapping_error(struct device *dev, dma_addr_t dma_addr)
+{
+	return 0;
+}
+
+struct dma_map_ops xtensa_dma_map_ops = {
+	.alloc = xtensa_dma_alloc,
+	.free = xtensa_dma_free,
+	.map_page = xtensa_map_page,
+	.unmap_page = xtensa_unmap_page,
+	.map_sg = xtensa_map_sg,
+	.unmap_sg = xtensa_unmap_sg,
+	.sync_single_for_cpu = xtensa_sync_single_for_cpu,
+	.sync_single_for_device = xtensa_sync_single_for_device,
+	.sync_sg_for_cpu = xtensa_sync_sg_for_cpu,
+	.sync_sg_for_device = xtensa_sync_sg_for_device,
+	.mapping_error = xtensa_dma_mapping_error,
+};
+EXPORT_SYMBOL(xtensa_dma_map_ops);
+
+#define PREALLOC_DMA_DEBUG_ENTRIES (1 << 16)
+
+static int __init xtensa_dma_init(void)
+{
+	dma_debug_init(PREALLOC_DMA_DEBUG_ENTRIES);
+	return 0;
+}
+fs_initcall(xtensa_dma_init);