[PATCH v2 1/3] dma-mapping: introduce new dma unmap and sync api variants

[Laurentiu Tudor]

From: Laurentiu Tudor <laurentiu.tudor@xxxxxxx>

Introduce a few new dma unmap and sync variants that, on top of the
original variants, return the virtual address corresponding to the
input dma address.
In order to implement this a new dma map op is added and used:
    void *get_virt_addr(dev, dma_handle);
It does the actual conversion of an input dma address to the output
virtual address.

Signed-off-by: Laurentiu Tudor <laurentiu.tudor@xxxxxxx>
---
 include/linux/dma-mapping.h | 55 +++++++++++++++++++++++++++++++++++++
 1 file changed, 55 insertions(+)

diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h
index 4a1c4fca475a..ae7bb8a84b9d 100644
--- a/include/linux/dma-mapping.h
+++ b/include/linux/dma-mapping.h
@@ -132,6 +132,7 @@ struct dma_map_ops {
 	u64 (*get_required_mask)(struct device *dev);
 	size_t (*max_mapping_size)(struct device *dev);
 	unsigned long (*get_merge_boundary)(struct device *dev);
+	void *(*get_virt_addr)(struct device *dev, dma_addr_t dma_handle);
 };
 
 #define DMA_MAPPING_ERROR		(~(dma_addr_t)0)
@@ -304,6 +305,21 @@ static inline void dma_unmap_page_attrs(struct device *dev, dma_addr_t addr,
 	debug_dma_unmap_page(dev, addr, size, dir);
 }
 
+static inline struct page *
+dma_unmap_page_attrs_desc(struct device *dev, dma_addr_t addr, size_t size,
+			  enum dma_data_direction dir, unsigned long attrs)
+{
+	const struct dma_map_ops *ops = get_dma_ops(dev);
+	void *ptr = NULL;
+
+	if (ops && ops->get_virt_addr)
+		ptr = ops->get_virt_addr(dev, addr);
+
+	dma_unmap_page_attrs(dev, addr, size, dir, attrs);
+
+	return ptr ? virt_to_page(ptr) : NULL;
+}
+
 /*
  * dma_maps_sg_attrs returns 0 on error and > 0 on success.
  * It should never return a value < 0.
@@ -390,6 +406,21 @@ static inline void dma_sync_single_for_cpu(struct device *dev, dma_addr_t addr,
 	debug_dma_sync_single_for_cpu(dev, addr, size, dir);
 }
 
+static inline void *
+dma_sync_single_for_cpu_desc(struct device *dev, dma_addr_t addr, size_t size,
+			     enum dma_data_direction dir)
+{
+	const struct dma_map_ops *ops = get_dma_ops(dev);
+	void *ptr = NULL;
+
+	if (ops && ops->get_virt_addr)
+		ptr = ops->get_virt_addr(dev, addr);
+
+	dma_sync_single_for_cpu(dev, addr, size, dir);
+
+	return ptr;
+}
+
 static inline void dma_sync_single_for_device(struct device *dev,
 					      dma_addr_t addr, size_t size,
 					      enum dma_data_direction dir)
@@ -500,6 +531,12 @@ static inline void dma_sync_single_for_cpu(struct device *dev, dma_addr_t addr,
 		size_t size, enum dma_data_direction dir)
 {
 }
+
+static inline void *
+dma_sync_single_for_cpu_desc(struct device *dev, dma_addr_t addr, size_t size,
+			     enum dma_data_direction dir)
+{
+}
 static inline void dma_sync_single_for_device(struct device *dev,
 		dma_addr_t addr, size_t size, enum dma_data_direction dir)
 {
@@ -594,6 +631,21 @@ static inline void dma_unmap_single_attrs(struct device *dev, dma_addr_t addr,
 	return dma_unmap_page_attrs(dev, addr, size, dir, attrs);
 }
 
+static inline void *
+dma_unmap_single_attrs_desc(struct device *dev, dma_addr_t addr, size_t size,
+			    enum dma_data_direction dir, unsigned long attrs)
+{
+	const struct dma_map_ops *ops = get_dma_ops(dev);
+	void *ptr = NULL;
+
+	if (ops && ops->get_virt_addr)
+		ptr = ops->get_virt_addr(dev, addr);
+
+	dma_unmap_single_attrs(dev, addr, size, dir, attrs);
+
+	return ptr;
+}
+
 static inline void dma_sync_single_range_for_cpu(struct device *dev,
 		dma_addr_t addr, unsigned long offset, size_t size,
 		enum dma_data_direction dir)
@@ -610,10 +662,13 @@ static inline void dma_sync_single_range_for_device(struct device *dev,
 
 #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_unmap_single_desc(d, a, s, r) \
+		dma_unmap_single_attrs_desc(d, a, s, r, 0)
 #define dma_map_sg(d, s, n, r) dma_map_sg_attrs(d, s, n, r, 0)
 #define dma_unmap_sg(d, s, n, r) dma_unmap_sg_attrs(d, s, n, r, 0)
 #define dma_map_page(d, p, o, s, r) dma_map_page_attrs(d, p, o, s, r, 0)
 #define dma_unmap_page(d, a, s, r) dma_unmap_page_attrs(d, a, s, r, 0)
+#define dma_unmap_page_desc(d, a, s, r) dma_unmap_page_attrs_desc(d, a, s, r, 0)
 #define dma_get_sgtable(d, t, v, h, s) dma_get_sgtable_attrs(d, t, v, h, s, 0)
 #define dma_mmap_coherent(d, v, c, h, s) dma_mmap_attrs(d, v, c, h, s, 0)
 
-- 
2.17.1