[PATCH 1/1] dmaengine: move driver-private helpers out of include/linux/dmaengine.h

From: Frank . Li

Date: Thu Oct 01 2026 - 11:00:11 EST


From: Frank Li <Frank.Li@xxxxxxx>

Move the following functions and declarations from the public header
include/linux/dmaengine.h into the driver-private header
drivers/dma/dmaengine.h, since they are only used by DMA engine drivers
and not by DMA engine consumers:

- dma_async_device_register()
- dmaenginem_async_device_register()
- dma_async_device_unregister()
- dma_async_device_channel_register()
- dma_async_device_channel_unregister()
- is_slave_direction()
- dmaengine_get_direction_text()

Signed-off-by: Frank Li <Frank.Li@xxxxxxx>
---
drivers/dma/dmaengine.h | 32 ++++++++++++++++++++++++++++++++
drivers/dma/dw/dw.c | 1 +
include/linux/dmaengine.h | 31 -------------------------------
3 files changed, 33 insertions(+), 31 deletions(-)

diff --git a/drivers/dma/dmaengine.h b/drivers/dma/dmaengine.h
index 53f16d3f00294..42a3cfa7e5970 100644
--- a/drivers/dma/dmaengine.h
+++ b/drivers/dma/dmaengine.h
@@ -182,6 +182,38 @@ dmaengine_desc_callback_valid(struct dmaengine_desc_callback *cb)
struct dma_chan *dma_get_slave_channel(struct dma_chan *chan);
struct dma_chan *dma_get_any_slave_channel(struct dma_device *device);

+static inline char *
+dmaengine_get_direction_text(enum dma_transfer_direction dir)
+{
+ switch (dir) {
+ case DMA_DEV_TO_MEM:
+ return "DEV_TO_MEM";
+ case DMA_MEM_TO_DEV:
+ return "MEM_TO_DEV";
+ case DMA_MEM_TO_MEM:
+ return "MEM_TO_MEM";
+ case DMA_DEV_TO_DEV:
+ return "DEV_TO_DEV";
+ default:
+ return "invalid";
+ }
+}
+
+static inline bool is_slave_direction(enum dma_transfer_direction direction)
+{
+ return (direction == DMA_MEM_TO_DEV) || (direction == DMA_DEV_TO_MEM) ||
+ (direction == DMA_DEV_TO_DEV);
+}
+
+int dma_async_device_register(struct dma_device *device);
+int dmaenginem_async_device_register(struct dma_device *device);
+void dma_async_device_unregister(struct dma_device *device);
+int dma_async_device_channel_register(struct dma_device *device,
+ struct dma_chan *chan,
+ const char *name);
+void dma_async_device_channel_unregister(struct dma_device *device,
+ struct dma_chan *chan);
+
#ifdef CONFIG_DEBUG_FS
#include <linux/debugfs.h>

diff --git a/drivers/dma/dw/dw.c b/drivers/dma/dw/dw.c
index 6766142884b66..e56974e7d4afb 100644
--- a/drivers/dma/dw/dw.c
+++ b/drivers/dma/dw/dw.c
@@ -9,6 +9,7 @@
#include <linux/slab.h>
#include <linux/types.h>

+#include "../dmaengine.h"
#include "internal.h"

static void dw_dma_initialize_chan(struct dw_dma_chan *dwc)
diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h
index 1b57bc4a7e72a..3203b5f81b21d 100644
--- a/include/linux/dmaengine.h
+++ b/include/linux/dmaengine.h
@@ -989,12 +989,6 @@ static inline int dmaengine_slave_config(struct dma_chan *chan,
return -ENOSYS;
}

-static inline bool is_slave_direction(enum dma_transfer_direction direction)
-{
- return (direction == DMA_MEM_TO_DEV) || (direction == DMA_DEV_TO_MEM) ||
- (direction == DMA_DEV_TO_DEV);
-}
-
static inline struct dma_async_tx_descriptor *
dmaengine_prep_config_single(struct dma_chan *chan, dma_addr_t buf, size_t len,
enum dma_transfer_direction dir,
@@ -1756,14 +1750,6 @@ static inline int dmaengine_desc_free(struct dma_async_tx_descriptor *desc)

/* --- DMA device --- */

-int dma_async_device_register(struct dma_device *device);
-int dmaenginem_async_device_register(struct dma_device *device);
-void dma_async_device_unregister(struct dma_device *device);
-int dma_async_device_channel_register(struct dma_device *device,
- struct dma_chan *chan,
- const char *name);
-void dma_async_device_channel_unregister(struct dma_device *device,
- struct dma_chan *chan);
void dma_run_dependencies(struct dma_async_tx_descriptor *tx);
#define dma_request_channel(mask, x, y) \
__dma_request_channel(&(mask), x, y, NULL)
@@ -1785,23 +1771,6 @@ static inline struct dma_chan
return dma_request_channel(mask, fn, fn_param);
}

-static inline char *
-dmaengine_get_direction_text(enum dma_transfer_direction dir)
-{
- switch (dir) {
- case DMA_DEV_TO_MEM:
- return "DEV_TO_MEM";
- case DMA_MEM_TO_DEV:
- return "MEM_TO_DEV";
- case DMA_MEM_TO_MEM:
- return "MEM_TO_MEM";
- case DMA_DEV_TO_DEV:
- return "DEV_TO_DEV";
- default:
- return "invalid";
- }
-}
-
static inline struct device *dmaengine_chan_dev(struct dma_chan *chan)
{
return &chan->chan_dev->device;
--
2.43.0