[PATCH 1/8] lib/scatterlist: add sg_set_dma_addr() helper

Christian König
2018-03-25T11:00:05Z

Use this function to set an sg entry to point to device resources mapped
using dma_map_resource(). The page pointer is set to NULL and only the DMA
address, length and offset values are valid.

Signed-off-by: Christian König <christian.koenig@amd.com>
---
include/linux/scatterlist.h | 23 +++++++++++++++++++++++
1 file changed, 23 insertions(+)

diff --git a/include/linux/scatterlist.h b/include/linux/scatterlist.h
index 22b2131bcdcd..f944ee4e482c 100644
--- a/include/linux/scatterlist.h
+++ b/include/linux/scatterlist.h
@@ -149,6 +149,29 @@ static inline void sg_set_buf(struct scatterlist *sg, const void *buf,
sg_set_page(sg, virt_to_page(buf), buflen, offset_in_page(buf));
}

+/**
+ * sg_set_dma_addr - Set sg entry to point at specified dma address
+ * @sg: SG entry
+ * @address: DMA address to set
+ * @len: Length of data
+ * @offset: Offset into page
+ *
+ * Description:
+ * Use this function to set an sg entry to point to device resources mapped
+ * using dma_map_resource(). The page pointer is set to NULL and only the DMA
+ * address, length and offset values are valid.
+ *
+ **/
+static inline void sg_set_dma_addr(struct scatterlist *sg, dma_addr_t address,
+ unsigned int len, unsigned int offset)
+{
+ sg_set_page(sg, NULL, len, offset);
+ sg->dma_address = address;
+#ifdef CONFIG_NEED_SG_DMA_LENGTH
+ sg->dma_length = len;
+#endif
+}
+
/*
* Loop over each sg element, following the pointer to a new list if necessary
*/
--
2.14.1