dmaengine: ack to flags: make use of the unused bits in the 'ack' field
'ack' is currently a simple integer that flags whether or not a client is done
touching fields in the given descriptor. It is effectively just a single bit
of information. Converting this to a flags parameter allows the other bits to
be put to use to control completion actions, like dma-unmap, and capture
results, like xor-zero-sum == 0.
Changes are one of:
1/ convert all open-coded ->ack manipulations to use async_tx_ack
and async_tx_test_ack.
2/ set the ack bit at prep time where possible
3/ make drivers store the flags at prep time
4/ add flags to the device_prep_dma_interrupt prototype
Acked-by: Maciej Sosnowski <maciej.sosnowski@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h
index cd34df7..b4d84ed 100644
--- a/include/linux/dmaengine.h
+++ b/include/linux/dmaengine.h
@@ -95,12 +95,17 @@
#define DMA_TX_TYPE_END (DMA_INTERRUPT + 1)
/**
- * enum dma_prep_flags - DMA flags to augment operation preparation
+ * enum dma_ctrl_flags - DMA flags to augment operation preparation,
+ * control completion, and communicate status.
* @DMA_PREP_INTERRUPT - trigger an interrupt (callback) upon completion of
* this transaction
+ * @DMA_CTRL_ACK - the descriptor cannot be reused until the client
+ * acknowledges receipt, i.e. has has a chance to establish any
+ * dependency chains
*/
-enum dma_prep_flags {
+enum dma_ctrl_flags {
DMA_PREP_INTERRUPT = (1 << 0),
+ DMA_CTRL_ACK = (1 << 1),
};
/**
@@ -211,8 +216,8 @@
* ---dma generic offload fields---
* @cookie: tracking cookie for this transaction, set to -EBUSY if
* this tx is sitting on a dependency list
- * @ack: the descriptor can not be reused until the client acknowledges
- * receipt, i.e. has has a chance to establish any dependency chains
+ * @flags: flags to augment operation preparation, control completion, and
+ * communicate status
* @phys: physical address of the descriptor
* @tx_list: driver common field for operations that require multiple
* descriptors
@@ -227,7 +232,7 @@
*/
struct dma_async_tx_descriptor {
dma_cookie_t cookie;
- int ack;
+ enum dma_ctrl_flags flags; /* not a 'long' to pack with cookie */
dma_addr_t phys;
struct list_head tx_list;
struct dma_chan *chan;
@@ -290,7 +295,7 @@
struct dma_chan *chan, dma_addr_t dest, int value, size_t len,
unsigned long flags);
struct dma_async_tx_descriptor *(*device_prep_dma_interrupt)(
- struct dma_chan *chan);
+ struct dma_chan *chan, unsigned long flags);
enum dma_status (*device_is_tx_complete)(struct dma_chan *chan,
dma_cookie_t cookie, dma_cookie_t *last,
@@ -316,7 +321,13 @@
static inline void
async_tx_ack(struct dma_async_tx_descriptor *tx)
{
- tx->ack = 1;
+ tx->flags |= DMA_CTRL_ACK;
+}
+
+static inline int
+async_tx_test_ack(struct dma_async_tx_descriptor *tx)
+{
+ return tx->flags & DMA_CTRL_ACK;
}
#define first_dma_cap(mask) __first_dma_cap(&(mask))