1 /*
2 * The contents of this file are private to DMA engine drivers, and is not
3 * part of the API to be used by DMA engine users.
4 */
5 #ifndef DMAENGINE_H
6 #define DMAENGINE_H
7
8 #include <linux/bug.h>
9 #include <linux/dmaengine.h>
10
11 /**
12 * dma_cookie_init - initialize the cookies for a DMA channel
13 * @chan: dma channel to initialize
14 */
dma_cookie_init(struct dma_chan * chan)15 static inline void dma_cookie_init(struct dma_chan *chan)
16 {
17 chan->cookie = DMA_MIN_COOKIE;
18 chan->completed_cookie = DMA_MIN_COOKIE;
19 }
20
21 /**
22 * dma_cookie_assign - assign a DMA engine cookie to the descriptor
23 * @tx: descriptor needing cookie
24 *
25 * Assign a unique non-zero per-channel cookie to the descriptor.
26 * Note: caller is expected to hold a lock to prevent concurrency.
27 */
dma_cookie_assign(struct dma_async_tx_descriptor * tx)28 static inline dma_cookie_t dma_cookie_assign(struct dma_async_tx_descriptor *tx)
29 {
30 struct dma_chan *chan = tx->chan;
31 dma_cookie_t cookie;
32
33 cookie = chan->cookie + 1;
34 if (cookie < DMA_MIN_COOKIE)
35 cookie = DMA_MIN_COOKIE;
36 tx->cookie = chan->cookie = cookie;
37
38 return cookie;
39 }
40
41 /**
42 * dma_cookie_complete - complete a descriptor
43 * @tx: descriptor to complete
44 *
45 * Mark this descriptor complete by updating the channels completed
46 * cookie marker. Zero the descriptors cookie to prevent accidental
47 * repeated completions.
48 *
49 * Note: caller is expected to hold a lock to prevent concurrency.
50 */
dma_cookie_complete(struct dma_async_tx_descriptor * tx)51 static inline void dma_cookie_complete(struct dma_async_tx_descriptor *tx)
52 {
53 BUG_ON(tx->cookie < DMA_MIN_COOKIE);
54 tx->chan->completed_cookie = tx->cookie;
55 tx->cookie = 0;
56 }
57
58 /**
59 * dma_cookie_status - report cookie status
60 * @chan: dma channel
61 * @cookie: cookie we are interested in
62 * @state: dma_tx_state structure to return last/used cookies
63 *
64 * Report the status of the cookie, filling in the state structure if
65 * non-NULL. No locking is required.
66 */
dma_cookie_status(struct dma_chan * chan,dma_cookie_t cookie,struct dma_tx_state * state)67 static inline enum dma_status dma_cookie_status(struct dma_chan *chan,
68 dma_cookie_t cookie, struct dma_tx_state *state)
69 {
70 dma_cookie_t used, complete;
71
72 used = chan->cookie;
73 complete = chan->completed_cookie;
74 barrier();
75 if (state) {
76 state->last = complete;
77 state->used = used;
78 state->residue = 0;
79 }
80 return dma_async_is_complete(cookie, complete, used);
81 }
82
dma_set_residue(struct dma_tx_state * state,u32 residue)83 static inline void dma_set_residue(struct dma_tx_state *state, u32 residue)
84 {
85 if (state)
86 state->residue = residue;
87 }
88
89 #endif
90