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authorMarek Szyprowski <m.szyprowski@samsung.com>2020-05-08 16:04:44 +0200
committerMarek Szyprowski <m.szyprowski@samsung.com>2020-09-10 08:17:48 +0200
commitd46e7ae24b81533d21edfa90914d27efa0c5f85d (patch)
treea97b32329877f5d95b9c41c7507d5672dba2754e /drivers/gpu/drm/drm_prime.c
parent9123e3a74ec7b934a4a099e98af6a61c2f80bbf5 (diff)
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drm: prime: add common helper to check scatterlist contiguity
It is a common operation done by DRM drivers to check the contiguity of the DMA-mapped buffer described by a scatterlist in the sg_table object. Let's add a common helper for this operation. Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com> Reviewed-by: Andrzej Hajda <a.hajda@samsung.com> Reviewed-by: Robin Murphy <robin.murphy@arm.com>
Diffstat (limited to 'drivers/gpu/drm/drm_prime.c')
-rw-r--r--drivers/gpu/drm/drm_prime.c31
1 files changed, 31 insertions, 0 deletions
diff --git a/drivers/gpu/drm/drm_prime.c b/drivers/gpu/drm/drm_prime.c
index 1693aa7c14b5..4ed5ed1f078c 100644
--- a/drivers/gpu/drm/drm_prime.c
+++ b/drivers/gpu/drm/drm_prime.c
@@ -826,6 +826,37 @@ out:
EXPORT_SYMBOL(drm_prime_pages_to_sg);
/**
+ * drm_prime_get_contiguous_size - returns the contiguous size of the buffer
+ * @sgt: sg_table describing the buffer to check
+ *
+ * This helper calculates the contiguous size in the DMA address space
+ * of the the buffer described by the provided sg_table.
+ *
+ * This is useful for implementing
+ * &drm_gem_object_funcs.gem_prime_import_sg_table.
+ */
+unsigned long drm_prime_get_contiguous_size(struct sg_table *sgt)
+{
+ dma_addr_t expected = sg_dma_address(sgt->sgl);
+ struct scatterlist *sg;
+ unsigned long size = 0;
+ int i;
+
+ for_each_sgtable_dma_sg(sgt, sg, i) {
+ unsigned int len = sg_dma_len(sg);
+
+ if (!len)
+ break;
+ if (sg_dma_address(sg) != expected)
+ break;
+ expected += len;
+ size += len;
+ }
+ return size;
+}
+EXPORT_SYMBOL(drm_prime_get_contiguous_size);
+
+/**
* drm_gem_prime_export - helper library implementation of the export callback
* @obj: GEM object to export
* @flags: flags like DRM_CLOEXEC and DRM_RDWR