Merge branch 'for-linus-3.4' of git://git.linaro.org/people/sumitsemwal/linux-dma-buf

Pull dma-buf updates from Sumit Semwal:
 "This includes the following key items:

   - kernel cpu access support,
   - flag-passing to dma_buf_fd,
   - relevant Documentation updates, and
   - some minor cleanups and fixes.

  These changes are needed for the drm prime/dma-buf interface code that
  Dave Airlie plans to submit in this merge window."

* 'for-linus-3.4' of git://git.linaro.org/people/sumitsemwal/linux-dma-buf:
  dma-buf: correct dummy function declarations.
  dma-buf: document fd flags and O_CLOEXEC requirement
  dma_buf: Add documentation for the new cpu access support
  dma-buf: add support for kernel cpu access
  dma-buf: don't hold the mutex around map/unmap calls
  dma-buf: add get_dma_buf()
  dma-buf: pass flags into dma_buf_fd.
  dma-buf: add dma_data_direction to unmap dma_buf_op
  dma-buf: Move code out of mutex-protected section in dma_buf_attach()
  dma-buf: Return error instead of using a goto statement when possible
  dma-buf: Remove unneeded sanity checks
  dma-buf: Constify ops argument to dma_buf_export()

1 files changed, 87 insertions, 10 deletions

diff --git a/include/linux/dma-buf.h b/include/linux/dma-buf.h
index 887dcd487062..3efbfc2145c3 100644
--- a/include/linux/dma-buf.h
+++ b/include/linux/dma-buf.h
@@ -29,6 +29,7 @@
 #include <linux/scatterlist.h>
 #include <linux/list.h>
 #include <linux/dma-mapping.h>
+#include <linux/fs.h>
 
 struct device;
 struct dma_buf;
@@ -49,6 +50,17 @@ struct dma_buf_attachment;
  * @unmap_dma_buf: decreases usecount of buffer, might deallocate scatter
  *                 pages.
  * @release: release this buffer; to be called after the last dma_buf_put.
+ * @begin_cpu_access: [optional] called before cpu access to invalidate cpu
+ *                    caches and allocate backing storage (if not yet done)
+ *                    respectively pin the objet into memory.
+ * @end_cpu_access: [optional] called after cpu access to flush cashes.
+ * @kmap_atomic: maps a page from the buffer into kernel address
+ *               space, users may not block until the subsequent unmap call.
+ *               This callback must not sleep.
+ * @kunmap_atomic: [optional] unmaps a atomically mapped page from the buffer.
+ *                 This Callback must not sleep.
+ * @kmap: maps a page from the buffer into kernel address space.
+ * @kunmap: [optional] unmaps a page from the buffer.
  */
 struct dma_buf_ops {
         int (*attach)(struct dma_buf *, struct device *,
@@ -63,7 +75,8 @@ struct dma_buf_ops {
         struct sg_table * (*map_dma_buf)(struct dma_buf_attachment *,
                                                 enum dma_data_direction);
         void (*unmap_dma_buf)(struct dma_buf_attachment *,
-                                                struct sg_table *);
+                                                struct sg_table *,
+                                                enum dma_data_direction);
         /* TODO: Add try_map_dma_buf version, to return immed with -EBUSY
          * if the call would block.
          */
@@ -71,6 +84,14 @@ struct dma_buf_ops {
         /* after final dma_buf_put() */
         void (*release)(struct dma_buf *);
 
+        int (*begin_cpu_access)(struct dma_buf *, size_t, size_t,
+                                enum dma_data_direction);
+        void (*end_cpu_access)(struct dma_buf *, size_t, size_t,
+                               enum dma_data_direction);
+        void *(*kmap_atomic)(struct dma_buf *, unsigned long);
+        void (*kunmap_atomic)(struct dma_buf *, unsigned long, void *);
+        void *(*kmap)(struct dma_buf *, unsigned long);
+        void (*kunmap)(struct dma_buf *, unsigned long, void *);
 };
 
 /**
@@ -86,7 +107,7 @@ struct dma_buf {
         struct file *file;
         struct list_head attachments;
         const struct dma_buf_ops *ops;
-        /* mutex to serialize list manipulation and other ops */
+        /* mutex to serialize list manipulation and attach/detach */
         struct mutex lock;
         void *priv;
 };
@@ -109,20 +130,43 @@ struct dma_buf_attachment {
         void *priv;
 };
 
+/**
+ * get_dma_buf - convenience wrapper for get_file.
+ * @dmabuf:     [in]    pointer to dma_buf
+ *
+ * Increments the reference count on the dma-buf, needed in case of drivers
+ * that either need to create additional references to the dmabuf on the
+ * kernel side.  For example, an exporter that needs to keep a dmabuf ptr
+ * so that subsequent exports don't create a new dmabuf.
+ */
+static inline void get_dma_buf(struct dma_buf *dmabuf)
+{
+        get_file(dmabuf->file);
+}
+
 #ifdef CONFIG_DMA_SHARED_BUFFER
 struct dma_buf_attachment *dma_buf_attach(struct dma_buf *dmabuf,
                                                         struct device *dev);
 void dma_buf_detach(struct dma_buf *dmabuf,
                                 struct dma_buf_attachment *dmabuf_attach);
-struct dma_buf *dma_buf_export(void *priv, struct dma_buf_ops *ops,
-                        size_t size, int flags);
-int dma_buf_fd(struct dma_buf *dmabuf);
+struct dma_buf *dma_buf_export(void *priv, const struct dma_buf_ops *ops,
+                               size_t size, int flags);
+int dma_buf_fd(struct dma_buf *dmabuf, int flags);
 struct dma_buf *dma_buf_get(int fd);
 void dma_buf_put(struct dma_buf *dmabuf);
 
 struct sg_table *dma_buf_map_attachment(struct dma_buf_attachment *,
                                         enum dma_data_direction);
-void dma_buf_unmap_attachment(struct dma_buf_attachment *, struct sg_table *);
+void dma_buf_unmap_attachment(struct dma_buf_attachment *, struct sg_table *,
+                                enum dma_data_direction);
+int dma_buf_begin_cpu_access(struct dma_buf *dma_buf, size_t start, size_t len,
+                             enum dma_data_direction dir);
+void dma_buf_end_cpu_access(struct dma_buf *dma_buf, size_t start, size_t len,
+                            enum dma_data_direction dir);
+void *dma_buf_kmap_atomic(struct dma_buf *, unsigned long);
+void dma_buf_kunmap_atomic(struct dma_buf *, unsigned long, void *);
+void *dma_buf_kmap(struct dma_buf *, unsigned long);
+void dma_buf_kunmap(struct dma_buf *, unsigned long, void *);
 #else
 
 static inline struct dma_buf_attachment *dma_buf_attach(struct dma_buf *dmabuf,
@@ -138,13 +182,13 @@ static inline void dma_buf_detach(struct dma_buf *dmabuf,
 }
 
 static inline struct dma_buf *dma_buf_export(void *priv,
-                                                struct dma_buf_ops *ops,
-                                                size_t size, int flags)
+                                             const struct dma_buf_ops *ops,
+                                             size_t size, int flags)
 {
         return ERR_PTR(-ENODEV);
 }
 
-static inline int dma_buf_fd(struct dma_buf *dmabuf)
+static inline int dma_buf_fd(struct dma_buf *dmabuf, int flags)
 {
         return -ENODEV;
 }
@@ -166,11 +210,44 @@ static inline struct sg_table *dma_buf_map_attachment(
 }
 
 static inline void dma_buf_unmap_attachment(struct dma_buf_attachment *attach,
-                                                struct sg_table *sg)
+                        struct sg_table *sg, enum dma_data_direction dir)
 {
         return;
 }
 
+static inline int dma_buf_begin_cpu_access(struct dma_buf *dmabuf,
+                                           size_t start, size_t len,
+                                           enum dma_data_direction dir)
+{
+        return -ENODEV;
+}
+
+static inline void dma_buf_end_cpu_access(struct dma_buf *dmabuf,
+                                          size_t start, size_t len,
+                                          enum dma_data_direction dir)
+{
+}
+
+static inline void *dma_buf_kmap_atomic(struct dma_buf *dmabuf,
+                                        unsigned long pnum)
+{
+        return NULL;
+}
+
+static inline void dma_buf_kunmap_atomic(struct dma_buf *dmabuf,
+                                         unsigned long pnum, void *vaddr)
+{
+}
+
+static inline void *dma_buf_kmap(struct dma_buf *dmabuf, unsigned long pnum)
+{
+        return NULL;
+}
+
+static inline void dma_buf_kunmap(struct dma_buf *dmabuf,
+                                  unsigned long pnum, void *vaddr)
+{
+}
 #endif /* CONFIG_DMA_SHARED_BUFFER */
 
 #endif /* __DMA_BUF_H__ */