[PATCH v4 01/15] dmaengine: Remove dma_async_is_complete from client API

From: Ben Walker
Date: Wed Jun 22 2022 - 15:38:23 EST


This is never actually used by any existing DMA clients. It is only
used, via dma_cookie_status, by providers.

Signed-off-by: Ben Walker <benjamin.walker@xxxxxxxxx>
---
Documentation/driver-api/dmaengine/client.rst | 5 ++--
drivers/dma/amba-pl08x.c | 1 -
drivers/dma/at_hdmac.c | 3 +-
drivers/dma/dmaengine.h | 10 ++++++-
include/linux/dmaengine.h | 28 ++-----------------
5 files changed, 15 insertions(+), 32 deletions(-)

diff --git a/Documentation/driver-api/dmaengine/client.rst b/Documentation/driver-api/dmaengine/client.rst
index bfd057b21a000..85ecec2c40005 100644
--- a/Documentation/driver-api/dmaengine/client.rst
+++ b/Documentation/driver-api/dmaengine/client.rst
@@ -346,9 +346,8 @@ Further APIs
the documentation in include/linux/dmaengine.h for a more complete
description of this API.

- This can be used in conjunction with dma_async_is_complete() and
- the cookie returned from dmaengine_submit() to check for
- completion of a specific DMA transaction.
+ This can be used with the cookie returned from dmaengine_submit()
+ to check for completion of a specific DMA transaction.

.. note::

diff --git a/drivers/dma/amba-pl08x.c b/drivers/dma/amba-pl08x.c
index a4a794e62ac26..bd361aee07db8 100644
--- a/drivers/dma/amba-pl08x.c
+++ b/drivers/dma/amba-pl08x.c
@@ -1536,7 +1536,6 @@ static void pl08x_free_chan_resources(struct dma_chan *chan)
}

/*
- * Code accessing dma_async_is_complete() in a tight loop may give problems.
* If slaves are relying on interrupts to signal completion this function
* must not be called with interrupts disabled.
*/
diff --git a/drivers/dma/at_hdmac.c b/drivers/dma/at_hdmac.c
index 5a50423b7378e..5ec9a36074771 100644
--- a/drivers/dma/at_hdmac.c
+++ b/drivers/dma/at_hdmac.c
@@ -1491,8 +1491,7 @@ static int atc_terminate_all(struct dma_chan *chan)
* @txstate: if not %NULL updated with transaction state
*
* If @txstate is passed in, upon return it reflect the driver
- * internal state and can be used with dma_async_is_complete() to check
- * the status of multiple cookies without re-checking hardware state.
+ * internal state.
*/
static enum dma_status
atc_tx_status(struct dma_chan *chan,
diff --git a/drivers/dma/dmaengine.h b/drivers/dma/dmaengine.h
index 53f16d3f00294..a2ce377e9ed0f 100644
--- a/drivers/dma/dmaengine.h
+++ b/drivers/dma/dmaengine.h
@@ -79,7 +79,15 @@ static inline enum dma_status dma_cookie_status(struct dma_chan *chan,
state->residue = 0;
state->in_flight_bytes = 0;
}
- return dma_async_is_complete(cookie, complete, used);
+
+ if (complete <= used) {
+ if ((cookie <= complete) || (cookie > used))
+ return DMA_COMPLETE;
+ } else {
+ if ((cookie <= complete) && (cookie > used))
+ return DMA_COMPLETE;
+ }
+ return DMA_IN_PROGRESS;
}

static inline void dma_set_residue(struct dma_tx_state *state, u32 residue)
diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h
index b46b88e6aa0d1..ea6ec2666eb15 100644
--- a/include/linux/dmaengine.h
+++ b/include/linux/dmaengine.h
@@ -1446,9 +1446,9 @@ static inline void dma_async_issue_pending(struct dma_chan *chan)
* @last: returns last completed cookie, can be NULL
* @used: returns last issued cookie, can be NULL
*
- * If @last and @used are passed in, upon return they reflect the driver
- * internal state and can be used with dma_async_is_complete() to check
- * the status of multiple cookies without re-checking hardware state.
+ * If @last and @used are passed in, upon return they reflect the most
+ * recently submitted (used) cookie and the most recently completed
+ * cookie.
*/
static inline enum dma_status dma_async_is_tx_complete(struct dma_chan *chan,
dma_cookie_t cookie, dma_cookie_t *last, dma_cookie_t *used)
@@ -1464,28 +1464,6 @@ static inline enum dma_status dma_async_is_tx_complete(struct dma_chan *chan,
return status;
}

-/**
- * dma_async_is_complete - test a cookie against chan state
- * @cookie: transaction identifier to test status of
- * @last_complete: last know completed transaction
- * @last_used: last cookie value handed out
- *
- * dma_async_is_complete() is used in dma_async_is_tx_complete()
- * the test logic is separated for lightweight testing of multiple cookies
- */
-static inline enum dma_status dma_async_is_complete(dma_cookie_t cookie,
- dma_cookie_t last_complete, dma_cookie_t last_used)
-{
- if (last_complete <= last_used) {
- if ((cookie <= last_complete) || (cookie > last_used))
- return DMA_COMPLETE;
- } else {
- if ((cookie <= last_complete) && (cookie > last_used))
- return DMA_COMPLETE;
- }
- return DMA_IN_PROGRESS;
-}
-
static inline void
dma_set_tx_state(struct dma_tx_state *st, dma_cookie_t last, dma_cookie_t used, u32 residue)
{
--
2.35.1