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-rw-r--r--drivers/dma/dmaengine.h89
1 files changed, 89 insertions, 0 deletions
diff --git a/drivers/dma/dmaengine.h b/drivers/dma/dmaengine.h
new file mode 100644
index 000000000000..17f983a4e9ba
--- /dev/null
+++ b/drivers/dma/dmaengine.h
@@ -0,0 +1,89 @@
+/*
+ * The contents of this file are private to DMA engine drivers, and is not
+ * part of the API to be used by DMA engine users.
+ */
+#ifndef DMAENGINE_H
+#define DMAENGINE_H
+
+#include <linux/bug.h>
+#include <linux/dmaengine.h>
+
+/**
+ * dma_cookie_init - initialize the cookies for a DMA channel
+ * @chan: dma channel to initialize
+ */
+static inline void dma_cookie_init(struct dma_chan *chan)
+{
+ chan->cookie = DMA_MIN_COOKIE;
+ chan->completed_cookie = DMA_MIN_COOKIE;
+}
+
+/**
+ * dma_cookie_assign - assign a DMA engine cookie to the descriptor
+ * @tx: descriptor needing cookie
+ *
+ * Assign a unique non-zero per-channel cookie to the descriptor.
+ * Note: caller is expected to hold a lock to prevent concurrency.
+ */
+static inline dma_cookie_t dma_cookie_assign(struct dma_async_tx_descriptor *tx)
+{
+ struct dma_chan *chan = tx->chan;
+ dma_cookie_t cookie;
+
+ cookie = chan->cookie + 1;
+ if (cookie < DMA_MIN_COOKIE)
+ cookie = DMA_MIN_COOKIE;
+ tx->cookie = chan->cookie = cookie;
+
+ return cookie;
+}
+
+/**
+ * dma_cookie_complete - complete a descriptor
+ * @tx: descriptor to complete
+ *
+ * Mark this descriptor complete by updating the channels completed
+ * cookie marker. Zero the descriptors cookie to prevent accidental
+ * repeated completions.
+ *
+ * Note: caller is expected to hold a lock to prevent concurrency.
+ */
+static inline void dma_cookie_complete(struct dma_async_tx_descriptor *tx)
+{
+ BUG_ON(tx->cookie < DMA_MIN_COOKIE);
+ tx->chan->completed_cookie = tx->cookie;
+ tx->cookie = 0;
+}
+
+/**
+ * dma_cookie_status - report cookie status
+ * @chan: dma channel
+ * @cookie: cookie we are interested in
+ * @state: dma_tx_state structure to return last/used cookies
+ *
+ * Report the status of the cookie, filling in the state structure if
+ * non-NULL. No locking is required.
+ */
+static inline enum dma_status dma_cookie_status(struct dma_chan *chan,
+ dma_cookie_t cookie, struct dma_tx_state *state)
+{
+ dma_cookie_t used, complete;
+
+ used = chan->cookie;
+ complete = chan->completed_cookie;
+ barrier();
+ if (state) {
+ state->last = complete;
+ state->used = used;
+ state->residue = 0;
+ }
+ return dma_async_is_complete(cookie, complete, used);
+}
+
+static inline void dma_set_residue(struct dma_tx_state *state, u32 residue)
+{
+ if (state)
+ state->residue = residue;
+}
+
+#endif