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Groups > linux.kernel > #1674555

[PATCH v6 2/7] dma: Add simple dma_noop_mmap

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This patch adds a simple implementation of mmap to dma_noop_ops.

Cc: Joerg Roedel <jroedel@suse.de>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Reported-by: Benjamin Gaignard <benjamin.gaignard@linaro.org>
Tested-by: Benjamin Gaignard <benjamin.gaignard@linaro.org>
Tested-by: Andras Szemzo <sza@esh.hu>
Tested-by: Alexandre TORGUE <alexandre.torgue@st.com>
Signed-off-by: Vladimir Murzin <vladimir.murzin@arm.com>
---
 lib/dma-noop.c | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/lib/dma-noop.c b/lib/dma-noop.c
index 1f60c8a..4b43d15 100644
--- a/lib/dma-noop.c
+++ b/lib/dma-noop.c
@@ -67,6 +67,29 @@ static int dma_noop_supported(struct device *dev, u64 mask)
 	return 1;
 }
 
+static int dma_noop_mmap(struct device *dev, struct vm_area_struct *vma,
+			 void *cpu_addr, dma_addr_t dma_addr, size_t size,
+			 unsigned long attrs)
+{
+	unsigned long user_count = vma_pages(vma);
+	unsigned long count = PAGE_ALIGN(size) >> PAGE_SHIFT;
+	unsigned long pfn = page_to_pfn(virt_to_page(cpu_addr));
+	unsigned long off = vma->vm_pgoff;
+	int ret = -ENXIO;
+
+	if (dma_mmap_from_coherent(dev, vma, cpu_addr, size, &ret))
+		return ret;
+
+	if (off < count && user_count <= (count - off)) {
+		ret = remap_pfn_range(vma, vma->vm_start,
+				      pfn + off,
+				      user_count << PAGE_SHIFT,
+				      vma->vm_page_prot);
+	}
+
+	return ret;
+}
+
 const struct dma_map_ops dma_noop_ops = {
 	.alloc			= dma_noop_alloc,
 	.free			= dma_noop_free,
@@ -74,6 +97,7 @@ const struct dma_map_ops dma_noop_ops = {
 	.map_sg			= dma_noop_map_sg,
 	.mapping_error		= dma_noop_mapping_error,
 	.dma_supported		= dma_noop_supported,
+	.mmap			= dma_noop_mmap,
 };
 
 EXPORT_SYMBOL(dma_noop_ops);
-- 
2.0.0

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[PATCH v6 0/7] ARM: Fix dma_alloc_coherent() and friends for NOMMU Vladimir Murzin <vladimir.murzin@arm.com> - 2017-06-26 11:20 +0200
  [PATCH v6 1/7] dma: Take into account dma_pfn_offset Vladimir Murzin <vladimir.murzin@arm.com> - 2017-06-26 11:30 +0200
  [PATCH v6 4/7] drivers: dma-coherent: Introduce default DMA pool Vladimir Murzin <vladimir.murzin@arm.com> - 2017-06-26 11:30 +0200
  [PATCH v6 5/7] ARM: NOMMU: Introduce dma operations for noMMU Vladimir Murzin <vladimir.murzin@arm.com> - 2017-06-26 11:30 +0200
  [PATCH v6 2/7] dma: Add simple dma_noop_mmap Vladimir Murzin <vladimir.murzin@arm.com> - 2017-06-26 11:30 +0200
  [PATCH v6 3/7] drivers: dma-coherent: Account dma_pfn_offset when used with device tree Vladimir Murzin <vladimir.murzin@arm.com> - 2017-06-26 11:30 +0200
  [PATCH v6 7/7] ARM: dma-mapping: Remove traces of NOMMU code Vladimir Murzin <vladimir.murzin@arm.com> - 2017-06-26 11:30 +0200
  [PATCH v6 6/7] ARM: NOMMU: Set ARM_DMA_MEM_BUFFERABLE for M-class cpus Vladimir Murzin <vladimir.murzin@arm.com> - 2017-06-26 11:30 +0200
  Re: [PATCH v6 0/7] ARM: Fix dma_alloc_coherent() and friends for         NOMMU Christoph Hellwig <hch@lst.de> - 2017-06-26 12:40 +0200
  Re: [PATCH v6 0/7] ARM: Fix dma_alloc_coherent() and friends for         NOMMU Christoph Hellwig <hch@lst.de> - 2017-06-27 17:30 +0200
    Re: [PATCH v6 0/7] ARM: Fix dma_alloc_coherent() and friends for  NOMMU Russell King - ARM Linux <linux@armlinux.org.uk> - 2017-06-27 19:00 +0200
      Re: [PATCH v6 0/7] ARM: Fix dma_alloc_coherent() and friends for         NOMMU Christoph Hellwig <hch@lst.de> - 2017-06-27 19:40 +0200
        Re: [PATCH v6 0/7] ARM: Fix dma_alloc_coherent() and friends for NOMMU Benjamin Gaignard <benjamin.gaignard@linaro.org> - 2017-06-28 09:40 +0200

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