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authorLinus Torvalds <torvalds@linux-foundation.org>2020-06-06 11:55:53 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2020-06-06 11:55:53 -0700
commit6f2dc3d335457d9c815be9f4fd3dc8eff92fcef7 (patch)
tree13a12ae70480fc6f0d64d44e74f3ea6311c1329f
parentMerge tag 'dma-mapping-5.8' of git://git.infradead.org/users/hch/dma-mapping (diff)
parentiommu: add generic helper for mapping sgtable objects (diff)
downloadwireguard-linux-6f2dc3d335457d9c815be9f4fd3dc8eff92fcef7.tar.xz
wireguard-linux-6f2dc3d335457d9c815be9f4fd3dc8eff92fcef7.zip
Merge tag 'dma-mapping-5.8-2' of git://git.infradead.org/users/hch/dma-mapping
Pull dma-mapping helpers from Christoph Hellwig: "These were in a separate stable branch so that various media and drm trees could pull the in for bug fixes, but looking at linux-next that hasn't actually happened yet. Still sending the APIs to you in the hope that these bug fixes get picked up for 5.8 in one way or another. Summary: - add DMA mapping helpers for struct sg_table (Marek Szyprowski)" * tag 'dma-mapping-5.8-2' of git://git.infradead.org/users/hch/dma-mapping: iommu: add generic helper for mapping sgtable objects scatterlist: add generic wrappers for iterating over sgtable objects dma-mapping: add generic helpers for mapping sgtable objects
-rw-r--r--include/linux/dma-mapping.h80
-rw-r--r--include/linux/iommu.h16
-rw-r--r--include/linux/scatterlist.h50
3 files changed, 143 insertions, 3 deletions
diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h
index b43116a6405d..78f677cf45ab 100644
--- a/include/linux/dma-mapping.h
+++ b/include/linux/dma-mapping.h
@@ -609,6 +609,86 @@ static inline void dma_sync_single_range_for_device(struct device *dev,
return dma_sync_single_for_device(dev, addr + offset, size, dir);
}
+/**
+ * dma_map_sgtable - Map the given buffer for DMA
+ * @dev: The device for which to perform the DMA operation
+ * @sgt: The sg_table object describing the buffer
+ * @dir: DMA direction
+ * @attrs: Optional DMA attributes for the map operation
+ *
+ * Maps a buffer described by a scatterlist stored in the given sg_table
+ * object for the @dir DMA operation by the @dev device. After success the
+ * ownership for the buffer is transferred to the DMA domain. One has to
+ * call dma_sync_sgtable_for_cpu() or dma_unmap_sgtable() to move the
+ * ownership of the buffer back to the CPU domain before touching the
+ * buffer by the CPU.
+ *
+ * Returns 0 on success or -EINVAL on error during mapping the buffer.
+ */
+static inline int dma_map_sgtable(struct device *dev, struct sg_table *sgt,
+ enum dma_data_direction dir, unsigned long attrs)
+{
+ int nents;
+
+ nents = dma_map_sg_attrs(dev, sgt->sgl, sgt->orig_nents, dir, attrs);
+ if (nents <= 0)
+ return -EINVAL;
+ sgt->nents = nents;
+ return 0;
+}
+
+/**
+ * dma_unmap_sgtable - Unmap the given buffer for DMA
+ * @dev: The device for which to perform the DMA operation
+ * @sgt: The sg_table object describing the buffer
+ * @dir: DMA direction
+ * @attrs: Optional DMA attributes for the unmap operation
+ *
+ * Unmaps a buffer described by a scatterlist stored in the given sg_table
+ * object for the @dir DMA operation by the @dev device. After this function
+ * the ownership of the buffer is transferred back to the CPU domain.
+ */
+static inline void dma_unmap_sgtable(struct device *dev, struct sg_table *sgt,
+ enum dma_data_direction dir, unsigned long attrs)
+{
+ dma_unmap_sg_attrs(dev, sgt->sgl, sgt->orig_nents, dir, attrs);
+}
+
+/**
+ * dma_sync_sgtable_for_cpu - Synchronize the given buffer for CPU access
+ * @dev: The device for which to perform the DMA operation
+ * @sgt: The sg_table object describing the buffer
+ * @dir: DMA direction
+ *
+ * Performs the needed cache synchronization and moves the ownership of the
+ * buffer back to the CPU domain, so it is safe to perform any access to it
+ * by the CPU. Before doing any further DMA operations, one has to transfer
+ * the ownership of the buffer back to the DMA domain by calling the
+ * dma_sync_sgtable_for_device().
+ */
+static inline void dma_sync_sgtable_for_cpu(struct device *dev,
+ struct sg_table *sgt, enum dma_data_direction dir)
+{
+ dma_sync_sg_for_cpu(dev, sgt->sgl, sgt->orig_nents, dir);
+}
+
+/**
+ * dma_sync_sgtable_for_device - Synchronize the given buffer for DMA
+ * @dev: The device for which to perform the DMA operation
+ * @sgt: The sg_table object describing the buffer
+ * @dir: DMA direction
+ *
+ * Performs the needed cache synchronization and moves the ownership of the
+ * buffer back to the DMA domain, so it is safe to perform the DMA operation.
+ * Once finished, one has to call dma_sync_sgtable_for_cpu() or
+ * dma_unmap_sgtable().
+ */
+static inline void dma_sync_sgtable_for_device(struct device *dev,
+ struct sg_table *sgt, enum dma_data_direction dir)
+{
+ dma_sync_sg_for_device(dev, sgt->sgl, sgt->orig_nents, dir);
+}
+
#define dma_map_single(d, a, s, r) dma_map_single_attrs(d, a, s, r, 0)
#define dma_unmap_single(d, a, s, r) dma_unmap_single_attrs(d, a, s, r, 0)
#define dma_map_sg(d, s, n, r) dma_map_sg_attrs(d, s, n, r, 0)
diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index 7ef8b0bda695..b1bfbe6dff42 100644
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -466,6 +466,22 @@ extern phys_addr_t iommu_iova_to_phys(struct iommu_domain *domain, dma_addr_t io
extern void iommu_set_fault_handler(struct iommu_domain *domain,
iommu_fault_handler_t handler, void *token);
+/**
+ * iommu_map_sgtable - Map the given buffer to the IOMMU domain
+ * @domain: The IOMMU domain to perform the mapping
+ * @iova: The start address to map the buffer
+ * @sgt: The sg_table object describing the buffer
+ * @prot: IOMMU protection bits
+ *
+ * Creates a mapping at @iova for the buffer described by a scatterlist
+ * stored in the given sg_table object in the provided IOMMU domain.
+ */
+static inline size_t iommu_map_sgtable(struct iommu_domain *domain,
+ unsigned long iova, struct sg_table *sgt, int prot)
+{
+ return iommu_map_sg(domain, iova, sgt->sgl, sgt->orig_nents, prot);
+}
+
extern void iommu_get_resv_regions(struct device *dev, struct list_head *list);
extern void iommu_put_resv_regions(struct device *dev, struct list_head *list);
extern void generic_iommu_put_resv_regions(struct device *dev,
diff --git a/include/linux/scatterlist.h b/include/linux/scatterlist.h
index 6eec50fb36c8..4f922afb607a 100644
--- a/include/linux/scatterlist.h
+++ b/include/linux/scatterlist.h
@@ -151,6 +151,20 @@ static inline void sg_set_buf(struct scatterlist *sg, const void *buf,
#define for_each_sg(sglist, sg, nr, __i) \
for (__i = 0, sg = (sglist); __i < (nr); __i++, sg = sg_next(sg))
+/*
+ * Loop over each sg element in the given sg_table object.
+ */
+#define for_each_sgtable_sg(sgt, sg, i) \
+ for_each_sg(sgt->sgl, sg, sgt->orig_nents, i)
+
+/*
+ * Loop over each sg element in the given *DMA mapped* sg_table object.
+ * Please use sg_dma_address(sg) and sg_dma_len(sg) to extract DMA addresses
+ * of the each element.
+ */
+#define for_each_sgtable_dma_sg(sgt, sg, i) \
+ for_each_sg(sgt->sgl, sg, sgt->nents, i)
+
/**
* sg_chain - Chain two sglists together
* @prv: First scatterlist
@@ -401,9 +415,10 @@ sg_page_iter_dma_address(struct sg_dma_page_iter *dma_iter)
* @sglist: sglist to iterate over
* @piter: page iterator to hold current page, sg, sg_pgoffset
* @nents: maximum number of sg entries to iterate over
- * @pgoffset: starting page offset
+ * @pgoffset: starting page offset (in pages)
*
* Callers may use sg_page_iter_page() to get each page pointer.
+ * In each loop it operates on PAGE_SIZE unit.
*/
#define for_each_sg_page(sglist, piter, nents, pgoffset) \
for (__sg_page_iter_start((piter), (sglist), (nents), (pgoffset)); \
@@ -412,18 +427,47 @@ sg_page_iter_dma_address(struct sg_dma_page_iter *dma_iter)
/**
* for_each_sg_dma_page - iterate over the pages of the given sg list
* @sglist: sglist to iterate over
- * @dma_iter: page iterator to hold current page
+ * @dma_iter: DMA page iterator to hold current page
* @dma_nents: maximum number of sg entries to iterate over, this is the value
* returned from dma_map_sg
- * @pgoffset: starting page offset
+ * @pgoffset: starting page offset (in pages)
*
* Callers may use sg_page_iter_dma_address() to get each page's DMA address.
+ * In each loop it operates on PAGE_SIZE unit.
*/
#define for_each_sg_dma_page(sglist, dma_iter, dma_nents, pgoffset) \
for (__sg_page_iter_start(&(dma_iter)->base, sglist, dma_nents, \
pgoffset); \
__sg_page_iter_dma_next(dma_iter);)
+/**
+ * for_each_sgtable_page - iterate over all pages in the sg_table object
+ * @sgt: sg_table object to iterate over
+ * @piter: page iterator to hold current page
+ * @pgoffset: starting page offset (in pages)
+ *
+ * Iterates over the all memory pages in the buffer described by
+ * a scatterlist stored in the given sg_table object.
+ * See also for_each_sg_page(). In each loop it operates on PAGE_SIZE unit.
+ */
+#define for_each_sgtable_page(sgt, piter, pgoffset) \
+ for_each_sg_page(sgt->sgl, piter, sgt->orig_nents, pgoffset)
+
+/**
+ * for_each_sgtable_dma_page - iterate over the DMA mapped sg_table object
+ * @sgt: sg_table object to iterate over
+ * @dma_iter: DMA page iterator to hold current page
+ * @pgoffset: starting page offset (in pages)
+ *
+ * Iterates over the all DMA mapped pages in the buffer described by
+ * a scatterlist stored in the given sg_table object.
+ * See also for_each_sg_dma_page(). In each loop it operates on PAGE_SIZE
+ * unit.
+ */
+#define for_each_sgtable_dma_page(sgt, dma_iter, pgoffset) \
+ for_each_sg_dma_page(sgt->sgl, dma_iter, sgt->nents, pgoffset)
+
+
/*
* Mapping sg iterator
*