Merge tag 'dma-mapping-5.20-2022-08-06' of git://git.infradead.org/users/hch/dma...

[linux-2.6-microblaze.git] / include / linux / scatterlist.h

diff --git a/include/linux/scatterlist.h b/include/linux/scatterlist.h
index 7ff9d63..375a5e9 100644 (file)
--- a/include/linux/scatterlist.h
+++ b/include/linux/scatterlist.h
@@ -16,6 +16,9 @@ struct scatterlist {
 #ifdef CONFIG_NEED_SG_DMA_LENGTH
        unsigned int    dma_length;
 #endif
+#ifdef CONFIG_PCI_P2PDMA
+       unsigned int    dma_flags;
+#endif
 };
 
 /*
@@ -245,6 +248,72 @@ static inline void sg_unmark_end(struct scatterlist *sg)
        sg->page_link &= ~SG_END;
 }
 
+/*
+ * CONFGI_PCI_P2PDMA depends on CONFIG_64BIT which means there is 4 bytes
+ * in struct scatterlist (assuming also CONFIG_NEED_SG_DMA_LENGTH is set).
+ * Use this padding for DMA flags bits to indicate when a specific
+ * dma address is a bus address.
+ */
+#ifdef CONFIG_PCI_P2PDMA
+
+#define SG_DMA_BUS_ADDRESS (1 << 0)
+
+/**
+ * sg_dma_is_bus address - Return whether a given segment was marked
+ *                        as a bus address
+ * @sg:                 SG entry
+ *
+ * Description:
+ *   Returns true if sg_dma_mark_bus_address() has been called on
+ *   this segment.
+ **/
+static inline bool sg_is_dma_bus_address(struct scatterlist *sg)
+{
+       return sg->dma_flags & SG_DMA_BUS_ADDRESS;
+}
+
+/**
+ * sg_dma_mark_bus address - Mark the scatterlist entry as a bus address
+ * @sg:                 SG entry
+ *
+ * Description:
+ *   Marks the passed in sg entry to indicate that the dma_address is
+ *   a bus address and doesn't need to be unmapped. This should only be
+ *   used by dma_map_sg() implementations to mark bus addresses
+ *   so they can be properly cleaned up in dma_unmap_sg().
+ **/
+static inline void sg_dma_mark_bus_address(struct scatterlist *sg)
+{
+       sg->dma_flags |= SG_DMA_BUS_ADDRESS;
+}
+
+/**
+ * sg_unmark_bus_address - Unmark the scatterlist entry as a bus address
+ * @sg:                 SG entry
+ *
+ * Description:
+ *   Clears the bus address mark.
+ **/
+static inline void sg_dma_unmark_bus_address(struct scatterlist *sg)
+{
+       sg->dma_flags &= ~SG_DMA_BUS_ADDRESS;
+}
+
+#else
+
+static inline bool sg_is_dma_bus_address(struct scatterlist *sg)
+{
+       return false;
+}
+static inline void sg_dma_mark_bus_address(struct scatterlist *sg)
+{
+}
+static inline void sg_dma_unmark_bus_address(struct scatterlist *sg)
+{
+}
+
+#endif
+
 /**
  * sg_phys - Return physical address of an sg entry
  * @sg:             SG entry