dmaengine: allow dma support for async_tx to be toggled

Provide a config option for blocking the allocation of dma channels to
the async_tx api.

Signed-off-by: Dan Williams <dan.j.williams@intel.com>

1 files changed, 18 insertions, 0 deletions

diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h
index 96e676e5bf9b..2afc2c95e42d 100644
--- a/include/linux/dmaengine.h
+++ b/include/linux/dmaengine.h
@@ -288,6 +288,24 @@ static inline void net_dmaengine_put(void)
 }
 #endif
 
+#ifdef CONFIG_ASYNC_TX_DMA
+#define async_dmaengine_get()   dmaengine_get()
+#define async_dmaengine_put()   dmaengine_put()
+#define async_dma_find_channel(type) dma_find_channel(type)
+#else
+static inline void async_dmaengine_get(void)
+{
+}
+static inline void async_dmaengine_put(void)
+{
+}
+static inline struct dma_chan *
+async_dma_find_channel(enum dma_transaction_type type)
+{
+        return NULL;
+}
+#endif
+
 dma_cookie_t dma_async_memcpy_buf_to_buf(struct dma_chan *chan,
         void *dest, void *src, size_t len);
 dma_cookie_t dma_async_memcpy_buf_to_pg(struct dma_chan *chan,