drivers/dma/dmaengine.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 /*
   3  * The contents of this file are private to DMA engine drivers, and is not
   4  * part of the API to be used by DMA engine users.
   5  */
   6 #ifndef DMAENGINE_H
   7 #define DMAENGINE_H
   8
   9 #include <linux/bug.h>
  10 #include <linux/dmaengine.h>
  11
  12 /**
  13  * dma_cookie_init - initialize the cookies for a DMA channel
  14  * @chan: dma channel to initialize
  15  */
  16 static inline void dma_cookie_init(struct dma_chan *chan)
  17 {
  18         chan->cookie = DMA_MIN_COOKIE;
  19         chan->completed_cookie = DMA_MIN_COOKIE;
  20 }
  21
  22 /**
  23  * dma_cookie_assign - assign a DMA engine cookie to the descriptor
  24  * @tx: descriptor needing cookie
  25  *
  26  * Assign a unique non-zero per-channel cookie to the descriptor.
  27  * Note: caller is expected to hold a lock to prevent concurrency.
  28  */
  29 static inline dma_cookie_t dma_cookie_assign(struct dma_async_tx_descriptor *tx)
  30 {
  31         struct dma_chan *chan = tx->chan;
  32         dma_cookie_t cookie;
  33
  34         cookie = chan->cookie + 1;
  35         if (cookie < DMA_MIN_COOKIE)
  36                 cookie = DMA_MIN_COOKIE;
  37         tx->cookie = chan->cookie = cookie;
  38
  39         return cookie;
  40 }
  41
  42 /**
  43  * dma_cookie_complete - complete a descriptor
  44  * @tx: descriptor to complete
  45  *
  46  * Mark this descriptor complete by updating the channels completed
  47  * cookie marker.  Zero the descriptors cookie to prevent accidental
  48  * repeated completions.
  49  *
  50  * Note: caller is expected to hold a lock to prevent concurrency.
  51  */
  52 static inline void dma_cookie_complete(struct dma_async_tx_descriptor *tx)
  53 {
  54         BUG_ON(tx->cookie < DMA_MIN_COOKIE);
  55         tx->chan->completed_cookie = tx->cookie;
  56         tx->cookie = 0;
  57 }
  58
  59 /**
  60  * dma_cookie_status - report cookie status
  61  * @chan: dma channel
  62  * @cookie: cookie we are interested in
  63  * @state: dma_tx_state structure to return last/used cookies
  64  *
  65  * Report the status of the cookie, filling in the state structure if
  66  * non-NULL.  No locking is required.
  67  */
  68 static inline enum dma_status dma_cookie_status(struct dma_chan *chan,
  69         dma_cookie_t cookie, struct dma_tx_state *state)
  70 {
  71         dma_cookie_t used, complete;
  72
  73         used = chan->cookie;
  74         complete = chan->completed_cookie;
  75         barrier();
  76         if (state) {
  77                 state->last = complete;
  78                 state->used = used;
  79                 state->residue = 0;
  80         }
  81         return dma_async_is_complete(cookie, complete, used);
  82 }
  83
  84 static inline void dma_set_residue(struct dma_tx_state *state, u32 residue)
  85 {
  86         if (state)
  87                 state->residue = residue;
  88 }
  89
  90 struct dmaengine_desc_callback {
  91         dma_async_tx_callback callback;
  92         dma_async_tx_callback_result callback_result;
  93         void *callback_param;
  94 };
  95
  96 /**
  97  * dmaengine_desc_get_callback - get the passed in callback function
  98  * @tx: tx descriptor
  99  * @cb: temp struct to hold the callback info
 100  *
 101  * Fill the passed in cb struct with what's available in the passed in
 102  * tx descriptor struct
 103  * No locking is required.
 104  */
 105 static inline void
 106 dmaengine_desc_get_callback(struct dma_async_tx_descriptor *tx,
 107                             struct dmaengine_desc_callback *cb)
 108 {
 109         cb->callback = tx->callback;
 110         cb->callback_result = tx->callback_result;
 111         cb->callback_param = tx->callback_param;
 112 }
 113
 114 /**
 115  * dmaengine_desc_callback_invoke - call the callback function in cb struct
 116  * @cb: temp struct that is holding the callback info
 117  * @result: transaction result
 118  *
 119  * Call the callback function provided in the cb struct with the parameter
 120  * in the cb struct.
 121  * Locking is dependent on the driver.
 122  */
 123 static inline void
 124 dmaengine_desc_callback_invoke(struct dmaengine_desc_callback *cb,
 125                                const struct dmaengine_result *result)
 126 {
 127         struct dmaengine_result dummy_result = {
 128                 .result = DMA_TRANS_NOERROR,
 129                 .residue = 0
 130         };
 131
 132         if (cb->callback_result) {
 133                 if (!result)
 134                         result = &dummy_result;
 135                 cb->callback_result(cb->callback_param, result);
 136         } else if (cb->callback) {
 137                 cb->callback(cb->callback_param);
 138         }
 139 }
 140
 141 /**
 142  * dmaengine_desc_get_callback_invoke - get the callback in tx descriptor and
 143  *                                      then immediately call the callback.
 144  * @tx: dma async tx descriptor
 145  * @result: transaction result
 146  *
 147  * Call dmaengine_desc_get_callback() and dmaengine_desc_callback_invoke()
 148  * in a single function since no work is necessary in between for the driver.
 149  * Locking is dependent on the driver.
 150  */
 151 static inline void
 152 dmaengine_desc_get_callback_invoke(struct dma_async_tx_descriptor *tx,
 153                                    const struct dmaengine_result *result)
 154 {
 155         struct dmaengine_desc_callback cb;
 156
 157         dmaengine_desc_get_callback(tx, &cb);
 158         dmaengine_desc_callback_invoke(&cb, result);
 159 }
 160
 161 /**
 162  * dmaengine_desc_callback_valid - verify the callback is valid in cb
 163  * @cb: callback info struct
 164  *
 165  * Return a bool that verifies whether callback in cb is valid or not.
 166  * No locking is required.
 167  */
 168 static inline bool
 169 dmaengine_desc_callback_valid(struct dmaengine_desc_callback *cb)
 170 {
 171         return (cb->callback) ? true : false;
 172 }
 173
 174 #endif