dma-mapping: add dma_{map,unmap}_resource

Map/Unmap a device MMIO resource from a physical address. If no dma_map_ops
method is available the operation is a no-op.

Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

2 files changed, 53 insertions, 5 deletions

diff --git a/Documentation/DMA-API.txt b/Documentation/DMA-API.txt
index 1d26eeb6b5f6..6b20128fab8a 100644
--- a/Documentation/DMA-API.txt
+++ b/Documentation/DMA-API.txt
@@ -277,14 +277,26 @@ and <size> parameters are provided to do partial page mapping, it is
 recommended that you never use these unless you really know what the
 cache width is.
 
+dma_addr_t
+dma_map_resource(struct device *dev, phys_addr_t phys_addr, size_t size,
+                 enum dma_data_direction dir, unsigned long attrs)
+
+void
+dma_unmap_resource(struct device *dev, dma_addr_t addr, size_t size,
+                   enum dma_data_direction dir, unsigned long attrs)
+
+API for mapping and unmapping for MMIO resources. All the notes and
+warnings for the other mapping APIs apply here. The API should only be
+used to map device MMIO resources, mapping of RAM is not permitted.
+
 int
 dma_mapping_error(struct device *dev, dma_addr_t dma_addr)
 
-In some circumstances dma_map_single() and dma_map_page() will fail to create
-a mapping. A driver can check for these errors by testing the returned
-DMA address with dma_mapping_error(). A non-zero return value means the mapping
-could not be created and the driver should take appropriate action (e.g.
-reduce current DMA mapping usage or delay and try again later).
+In some circumstances dma_map_single(), dma_map_page() and dma_map_resource()
+will fail to create a mapping. A driver can check for these errors by testing
+the returned DMA address with dma_mapping_error(). A non-zero return value
+means the mapping could not be created and the driver should take appropriate
+action (e.g. reduce current DMA mapping usage or delay and try again later).
 
         int
         dma_map_sg(struct device *dev, struct scatterlist *sg,
diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h
index 673b7be85f7a..6e00c7fdbbd3 100644
--- a/include/linux/dma-mapping.h
+++ b/include/linux/dma-mapping.h
@@ -264,6 +264,42 @@ static inline void dma_unmap_page(struct device *dev, dma_addr_t addr,
         debug_dma_unmap_page(dev, addr, size, dir, false);
 }
 
+static inline dma_addr_t dma_map_resource(struct device *dev,
+                                          phys_addr_t phys_addr,
+                                          size_t size,
+                                          enum dma_data_direction dir,
+                                          unsigned long attrs)
+{
+        struct dma_map_ops *ops = get_dma_ops(dev);
+        unsigned long pfn = __phys_to_pfn(phys_addr);
+        dma_addr_t addr;
+
+        BUG_ON(!valid_dma_direction(dir));
+
+        /* Don't allow RAM to be mapped */
+        BUG_ON(pfn_valid(pfn));
+
+        addr = phys_addr;
+        if (ops->map_resource)
+                addr = ops->map_resource(dev, phys_addr, size, dir, attrs);
+
+        debug_dma_map_resource(dev, phys_addr, size, dir, addr);
+
+        return addr;
+}
+
+static inline void dma_unmap_resource(struct device *dev, dma_addr_t addr,
+                                      size_t size, enum dma_data_direction dir,
+                                      unsigned long attrs)
+{
+        struct dma_map_ops *ops = get_dma_ops(dev);
+
+        BUG_ON(!valid_dma_direction(dir));
+        if (ops->unmap_resource)
+                ops->unmap_resource(dev, addr, size, dir, attrs);
+        debug_dma_unmap_resource(dev, addr, size, dir);
+}
+
 static inline void dma_sync_single_for_cpu(struct device *dev, dma_addr_t addr,
                                            size_t size,
                                            enum dma_data_direction dir)