From: Christoph Hellwig <hch@lst.de>
To: Mauro Carvalho Chehab <mchehab@kernel.org>,
Marek Szyprowski <m.szyprowski@samsung.com>,
Tomasz Figa <tfiga@chromium.org>,
Ricardo Ribalda <ribalda@chromium.org>,
Sergey Senozhatsky <senozhatsky@google.com>,
iommu@lists.linux-foundation.org
Cc: Robin Murphy <robin.murphy@arm.com>,
linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-media@vger.kernel.org
Subject: [PATCH 2/6] dma-mapping: add a dma_mmap_pages helper
Date: Thu, 28 Jan 2021 15:58:33 +0100 [thread overview]
Message-ID: <20210128145837.2250561-3-hch@lst.de> (raw)
In-Reply-To: <20210128145837.2250561-1-hch@lst.de>
Add a helper to map memory allocated using dma_alloc_pages into
a user address space, similar to the dma_alloc_attrs function for
coherent allocations.
Signed-off-by: Christoph Hellwig <hch@lst.de>
---
Documentation/core-api/dma-api.rst | 10 ++++++++++
include/linux/dma-mapping.h | 2 ++
kernel/dma/mapping.c | 13 +++++++++++++
3 files changed, 25 insertions(+)
diff --git a/Documentation/core-api/dma-api.rst b/Documentation/core-api/dma-api.rst
index e6d23f117308df..157a474ae54416 100644
--- a/Documentation/core-api/dma-api.rst
+++ b/Documentation/core-api/dma-api.rst
@@ -563,6 +563,16 @@ Free a region of memory previously allocated using dma_alloc_pages().
dev, size, dma_handle and dir must all be the same as those passed into
dma_alloc_pages(). page must be the pointer returned by dma_alloc_pages().
+::
+
+ int
+ dma_mmap_pages(struct device *dev, struct vm_area_struct *vma,
+ size_t size, struct page *page)
+
+Map an allocation returned from dma_alloc_pages() into a user address space.
+dev and size must be the same as those passed into dma_alloc_pages().
+page must be the pointer returned by dma_alloc_pages().
+
::
void *
diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h
index fbfa3f5abd9498..4977a748cb9483 100644
--- a/include/linux/dma-mapping.h
+++ b/include/linux/dma-mapping.h
@@ -263,6 +263,8 @@ struct page *dma_alloc_pages(struct device *dev, size_t size,
dma_addr_t *dma_handle, enum dma_data_direction dir, gfp_t gfp);
void dma_free_pages(struct device *dev, size_t size, struct page *page,
dma_addr_t dma_handle, enum dma_data_direction dir);
+int dma_mmap_pages(struct device *dev, struct vm_area_struct *vma,
+ size_t size, struct page *page);
static inline void *dma_alloc_noncoherent(struct device *dev, size_t size,
dma_addr_t *dma_handle, enum dma_data_direction dir, gfp_t gfp)
diff --git a/kernel/dma/mapping.c b/kernel/dma/mapping.c
index 68992e35c8c3a7..c1e515496c067b 100644
--- a/kernel/dma/mapping.c
+++ b/kernel/dma/mapping.c
@@ -515,6 +515,19 @@ void dma_free_pages(struct device *dev, size_t size, struct page *page,
}
EXPORT_SYMBOL_GPL(dma_free_pages);
+int dma_mmap_pages(struct device *dev, struct vm_area_struct *vma,
+ size_t size, struct page *page)
+{
+ unsigned long count = PAGE_ALIGN(size) >> PAGE_SHIFT;
+
+ if (vma->vm_pgoff >= count || vma_pages(vma) > count - vma->vm_pgoff)
+ return -ENXIO;
+ return remap_pfn_range(vma, vma->vm_start,
+ page_to_pfn(page) + vma->vm_pgoff,
+ vma_pages(vma) << PAGE_SHIFT, vma->vm_page_prot);
+}
+EXPORT_SYMBOL_GPL(dma_mmap_pages);
+
int dma_supported(struct device *dev, u64 mask)
{
const struct dma_map_ops *ops = get_dma_ops(dev);
--
2.29.2
next prev parent reply other threads:[~2021-01-28 15:05 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-28 14:58 add a new dma_alloc_noncontiguous API Christoph Hellwig
2021-01-28 14:58 ` [PATCH 1/6] dma-mapping: remove the {alloc,free}_noncoherent methods Christoph Hellwig
2021-01-28 14:58 ` Christoph Hellwig [this message]
2021-01-28 15:41 ` [PATCH 2/6] dma-mapping: add a dma_mmap_pages helper David Laight
2021-01-28 14:58 ` [PATCH 3/6] dma-mapping: add a dma_alloc_noncontiguous API Christoph Hellwig
2021-01-28 14:58 ` [PATCH 4/6] dma-iommu: refactor iommu_dma_alloc_remap Christoph Hellwig
2021-01-28 14:58 ` [PATCH 5/6] dma-iommu: implement ->alloc_noncontiguous Christoph Hellwig
2021-01-28 14:58 ` [PATCH 6/6] media: uvcvideo: Use dma_alloc_noncontiguos API Christoph Hellwig
2021-01-28 15:09 ` Christoph Hellwig
2021-01-28 17:00 ` Ricardo Ribalda
2021-02-01 16:37 ` Christoph Hellwig
2021-01-28 16:43 ` Ricardo Ribalda
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