[PATCH 24/33] dma-direct: use phys_to_dma

Christoph Hellwig
2018-01-10T08:00:18Z

This means it uses whatever linear remapping scheme that the architecture
provides is used in the generic dma_direct ops.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Vladimir Murzin <vladimir.murzin@arm.com>
---
lib/dma-direct.c | 18 +++++++-----------
1 file changed, 7 insertions(+), 11 deletions(-)

diff --git a/lib/dma-direct.c b/lib/dma-direct.c
index 0ec3262a3148..12ea9653781b 100644
--- a/lib/dma-direct.c
+++ b/lib/dma-direct.c
@@ -1,12 +1,11 @@
// SPDX-License-Identifier: GPL-2.0
/*
- * lib/dma-noop.c
- *
- * DMA operations that map to physical addresses without flushing memory.
+ * DMA operations that map physical memory directly without using an IOMMU or
+ * flushing caches.
*/
#include <linux/export.h>
#include <linux/mm.h>
-#include <linux/dma-mapping.h>
+#include <linux/dma-direct.h>
#include <linux/scatterlist.h>
#include <linux/pfn.h>

@@ -17,7 +16,7 @@ static void *dma_direct_alloc(struct device *dev, size_t size,

ret = (void *)__get_free_pages(gfp, get_order(size));
if (ret)
- *dma_handle = virt_to_phys(ret) - PFN_PHYS(dev->dma_pfn_offset);
+ *dma_handle = phys_to_dma(dev, virt_to_phys(ret));

return ret;
}
@@ -32,7 +31,7 @@ static dma_addr_t dma_direct_map_page(struct device *dev, struct page *page,
unsigned long offset, size_t size, enum dma_data_direction dir,
unsigned long attrs)
{
- return page_to_phys(page) + offset - PFN_PHYS(dev->dma_pfn_offset);
+ return phys_to_dma(dev, page_to_phys(page)) + offset;
}

static int dma_direct_map_sg(struct device *dev, struct scatterlist *sgl,
@@ -42,12 +41,9 @@ static int dma_direct_map_sg(struct device *dev, struct scatterlist *sgl,
struct scatterlist *sg;

for_each_sg(sgl, sg, nents, i) {
- dma_addr_t offset = PFN_PHYS(dev->dma_pfn_offset);
- void *va;
-
BUG_ON(!sg_page(sg));
- va = sg_virt(sg);
- sg_dma_address(sg) = (dma_addr_t)virt_to_phys(va) - offset;
+
+ sg_dma_address(sg) = phys_to_dma(dev, sg_phys(sg));
sg_dma_len(sg) = sg->length;
}

--
2.14.2