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Diffstat (limited to 'include/linux/dmaengine.h')
-rw-r--r--include/linux/dmaengine.h40
1 files changed, 40 insertions, 0 deletions
diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h
index 8ad9a4e839f6..1b866e9a6ed1 100644
--- a/include/linux/dmaengine.h
+++ b/include/linux/dmaengine.h
@@ -184,6 +184,8 @@ struct dma_interleaved_template {
* operation it continues the calculation with new sources
* @DMA_PREP_FENCE - tell the driver that subsequent operations depend
* on the result of this operation
+ * @DMA_CTRL_REUSE: client can reuse the descriptor and submit again till
+ * cleared or freed
*/
enum dma_ctrl_flags {
DMA_PREP_INTERRUPT = (1 << 0),
@@ -192,6 +194,7 @@ enum dma_ctrl_flags {
DMA_PREP_PQ_DISABLE_Q = (1 << 3),
DMA_PREP_CONTINUE = (1 << 4),
DMA_PREP_FENCE = (1 << 5),
+ DMA_CTRL_REUSE = (1 << 6),
};
/**
@@ -401,6 +404,8 @@ enum dma_residue_granularity {
* @cmd_pause: true, if pause and thereby resume is supported
* @cmd_terminate: true, if terminate cmd is supported
* @residue_granularity: granularity of the reported transfer residue
+ * @descriptor_reuse: if a descriptor can be reused by client and
+ * resubmitted multiple times
*/
struct dma_slave_caps {
u32 src_addr_widths;
@@ -409,6 +414,7 @@ struct dma_slave_caps {
bool cmd_pause;
bool cmd_terminate;
enum dma_residue_granularity residue_granularity;
+ bool descriptor_reuse;
};
static inline const char *dma_chan_name(struct dma_chan *chan)
@@ -468,6 +474,7 @@ struct dma_async_tx_descriptor {
dma_addr_t phys;
struct dma_chan *chan;
dma_cookie_t (*tx_submit)(struct dma_async_tx_descriptor *tx);
+ int (*desc_free)(struct dma_async_tx_descriptor *tx);
dma_async_tx_callback callback;
void *callback_param;
struct dmaengine_unmap_data *unmap;
@@ -1175,6 +1182,39 @@ static inline int dma_get_slave_caps(struct dma_chan *chan,
}
#endif
+static inline int dmaengine_desc_set_reuse(struct dma_async_tx_descriptor *tx)
+{
+ struct dma_slave_caps caps;
+
+ dma_get_slave_caps(tx->chan, &caps);
+
+ if (caps.descriptor_reuse) {
+ tx->flags |= DMA_CTRL_REUSE;
+ return 0;
+ } else {
+ return -EPERM;
+ }
+}
+
+static inline void dmaengine_desc_clear_reuse(struct dma_async_tx_descriptor *tx)
+{
+ tx->flags &= ~DMA_CTRL_REUSE;
+}
+
+static inline bool dmaengine_desc_test_reuse(struct dma_async_tx_descriptor *tx)
+{
+ return (tx->flags & DMA_CTRL_REUSE) == DMA_CTRL_REUSE;
+}
+
+static inline int dmaengine_desc_free(struct dma_async_tx_descriptor *desc)
+{
+ /* this is supported for reusable desc, so check that */
+ if (dmaengine_desc_test_reuse(desc))
+ return desc->desc_free(desc);
+ else
+ return -EPERM;
+}
+
/* --- DMA device --- */
int dma_async_device_register(struct dma_device *device);