1 files changed, 51 insertions, 3 deletions

diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h
index cb286b1acdb6..0bc727534108 100644
--- a/include/linux/dmaengine.h
+++ b/include/linux/dmaengine.h
@@ -38,7 +38,10 @@ typedef s32 dma_cookie_t;
 #define DMA_MIN_COOKIE  1
 #define DMA_MAX_COOKIE  INT_MAX
 
-#define dma_submit_error(cookie) ((cookie) < 0 ? 1 : 0)
+static inline int dma_submit_error(dma_cookie_t cookie)
+{
+        return cookie < 0 ? cookie : 0;
+}
 
 /**
  * enum dma_status - DMA transaction status
@@ -370,6 +373,25 @@ struct dma_slave_config {
         unsigned int slave_id;
 };
 
+/* struct dma_slave_caps - expose capabilities of a slave channel only
+ *
+ * @src_addr_widths: bit mask of src addr widths the channel supports
+ * @dstn_addr_widths: bit mask of dstn addr widths the channel supports
+ * @directions: bit mask of slave direction the channel supported
+ *      since the enum dma_transfer_direction is not defined as bits for each
+ *      type of direction, the dma controller should fill (1 << <TYPE>) and same
+ *      should be checked by controller as well
+ * @cmd_pause: true, if pause and thereby resume is supported
+ * @cmd_terminate: true, if terminate cmd is supported
+ */
+struct dma_slave_caps {
+        u32 src_addr_widths;
+        u32 dstn_addr_widths;
+        u32 directions;
+        bool cmd_pause;
+        bool cmd_terminate;
+};
+
 static inline const char *dma_chan_name(struct dma_chan *chan)
 {
         return dev_name(&chan->dev->device);
@@ -532,6 +554,7 @@ struct dma_tx_state {
  *      struct with auxiliary transfer status information, otherwise the call
  *      will just return a simple status code
  * @device_issue_pending: push pending transactions to hardware
+ * @device_slave_caps: return the slave channel capabilities
  */
 struct dma_device {
 
@@ -597,6 +620,7 @@ struct dma_device {
                                             dma_cookie_t cookie,
                                             struct dma_tx_state *txstate);
         void (*device_issue_pending)(struct dma_chan *chan);
+        int (*device_slave_caps)(struct dma_chan *chan, struct dma_slave_caps *caps);
 };
 
 static inline int dmaengine_device_control(struct dma_chan *chan,
@@ -670,6 +694,21 @@ static inline struct dma_async_tx_descriptor *dmaengine_prep_interleaved_dma(
         return chan->device->device_prep_interleaved_dma(chan, xt, flags);
 }
 
+static inline int dma_get_slave_caps(struct dma_chan *chan, struct dma_slave_caps *caps)
+{
+        if (!chan || !caps)
+                return -EINVAL;
+
+        /* check if the channel supports slave transactions */
+        if (!test_bit(DMA_SLAVE, chan->device->cap_mask.bits))
+                return -ENXIO;
+
+        if (chan->device->device_slave_caps)
+                return chan->device->device_slave_caps(chan, caps);
+
+        return -ENXIO;
+}
+
 static inline int dmaengine_terminate_all(struct dma_chan *chan)
 {
         return dmaengine_device_control(chan, DMA_TERMINATE_ALL, 0);
@@ -958,8 +997,9 @@ dma_set_tx_state(struct dma_tx_state *st, dma_cookie_t last, dma_cookie_t used,
         }
 }
 
-enum dma_status dma_sync_wait(struct dma_chan *chan, dma_cookie_t cookie);
 #ifdef CONFIG_DMA_ENGINE
+struct dma_chan *dma_find_channel(enum dma_transaction_type tx_type);
+enum dma_status dma_sync_wait(struct dma_chan *chan, dma_cookie_t cookie);
 enum dma_status dma_wait_for_async_tx(struct dma_async_tx_descriptor *tx);
 void dma_issue_pending_all(void);
 struct dma_chan *__dma_request_channel(const dma_cap_mask_t *mask,
@@ -967,6 +1007,14 @@ struct dma_chan *__dma_request_channel(const dma_cap_mask_t *mask,
 struct dma_chan *dma_request_slave_channel(struct device *dev, const char *name);
 void dma_release_channel(struct dma_chan *chan);
 #else
+static inline struct dma_chan *dma_find_channel(enum dma_transaction_type tx_type)
+{
+        return NULL;
+}
+static inline enum dma_status dma_sync_wait(struct dma_chan *chan, dma_cookie_t cookie)
+{
+        return DMA_SUCCESS;
+}
 static inline enum dma_status dma_wait_for_async_tx(struct dma_async_tx_descriptor *tx)
 {
         return DMA_SUCCESS;
@@ -994,7 +1042,7 @@ static inline void dma_release_channel(struct dma_chan *chan)
 int dma_async_device_register(struct dma_device *device);
 void dma_async_device_unregister(struct dma_device *device);
 void dma_run_dependencies(struct dma_async_tx_descriptor *tx);
-struct dma_chan *dma_find_channel(enum dma_transaction_type tx_type);
+struct dma_chan *dma_get_slave_channel(struct dma_chan *chan);
 struct dma_chan *net_dma_find_channel(void);
 #define dma_request_channel(mask, x, y) __dma_request_channel(&(mask), x, y)
 #define dma_request_slave_channel_compat(mask, x, y, dev, name) \