Re: [PATCH v5 3/7] dmaengine: Add dmaengine_async_is_tx_complete

"Walker, Benjamin" <benjamin.walker@xxxxxxxxx> · Wed, 19 Oct 2022 10:08:52 -0700

On 10/19/2022 9:31 AM, Vinod Koul wrote:
On 29-08-22, 13:35, Ben Walker wrote:
This is the replacement for dma_async_is_tx_complete with two changes:
1) The name prefix is 'dmaengine' as per convention
2) It no longer reports the 'last' or 'used' cookie

Thanks for this cleanup. This is good :)

But, why should we retain async is API here. I think lets cleanup
properly and rename it dmaengine_is_tx_complete()

we _really_ need to drop async and have everything dmaengine_*

Ack. Misunderstood earlier feedback to change dma -> dmaengine. I agree 
the async needs to go. Fixed in next version.



Drivers should convert to using dmaengine_async_is_tx_complete.

Signed-off-by: Ben Walker <benjamin.walker@xxxxxxxxx>
---
  Documentation/driver-api/dmaengine/client.rst | 19 ++++---------------
  .../driver-api/dmaengine/provider.rst         |  6 +++---
  drivers/dma/dmaengine.c                       |  2 +-
  drivers/dma/dmatest.c                         |  3 +--
  include/linux/dmaengine.h                     | 16 ++++++++++++++++
  5 files changed, 25 insertions(+), 21 deletions(-)

diff --git a/Documentation/driver-api/dmaengine/client.rst b/Documentation/driver-api/dmaengine/client.rst
index 85ecec2c40005..9ae489a4ca97f 100644
--- a/Documentation/driver-api/dmaengine/client.rst
+++ b/Documentation/driver-api/dmaengine/client.rst
@@ -259,8 +259,8 @@ The details of these operations are:
  
        dma_cookie_t dmaengine_submit(struct dma_async_tx_descriptor *desc)
  
-   This returns a cookie can be used to check the progress of DMA engine
-   activity via other DMA engine calls not covered in this document.
+   This returns a cookie that can be used to check the progress of a transaction
+   via dmaengine_async_is_tx_complete().
  
     dmaengine_submit() will not start the DMA operation, it merely adds
     it to the pending queue. For this, see step 5, dma_async_issue_pending.
@@ -339,23 +339,12 @@ Further APIs
  
     .. code-block:: c
  
-      enum dma_status dma_async_is_tx_complete(struct dma_chan *chan,
-		dma_cookie_t cookie, dma_cookie_t *last, dma_cookie_t *used)
-
-   This can be used to check the status of the channel. Please see
-   the documentation in include/linux/dmaengine.h for a more complete
-   description of this API.
+      enum dma_status dmaengine_async_is_tx_complete(struct dma_chan *chan,
+		dma_cookie_t cookie)
  
     This can be used with the cookie returned from dmaengine_submit()
     to check for completion of a specific DMA transaction.
  
-   .. note::
-
-      Not all DMA engine drivers can return reliable information for
-      a running DMA channel. It is recommended that DMA engine users
-      pause or stop (via dmaengine_terminate_all()) the channel before
-      using this API.
-
  5. Synchronize termination API
  
     .. code-block:: c
diff --git a/Documentation/driver-api/dmaengine/provider.rst b/Documentation/driver-api/dmaengine/provider.rst
index ceac2a300e328..1d0da2777921d 100644
--- a/Documentation/driver-api/dmaengine/provider.rst
+++ b/Documentation/driver-api/dmaengine/provider.rst
@@ -539,10 +539,10 @@ where to put them)
  
  dma_cookie_t
  
-- it's a DMA transaction ID that will increment over time.
+- it's a DMA transaction ID.
  
-- Not really relevant any more since the introduction of ``virt-dma``
-  that abstracts it away.
+- The value can be chosen by the provider, or use the helper APIs
+  such as dma_cookie_assign() and dma_cookie_complete().
  
  DMA_CTRL_ACK
  
diff --git a/drivers/dma/dmaengine.c b/drivers/dma/dmaengine.c
index c741b6431958c..2816b8f492dab 100644
--- a/drivers/dma/dmaengine.c
+++ b/drivers/dma/dmaengine.c
@@ -523,7 +523,7 @@ enum dma_status dma_sync_wait(struct dma_chan *chan, dma_cookie_t cookie)
  
  	dma_async_issue_pending(chan);
  	do {
-		status = dma_async_is_tx_complete(chan, cookie, NULL, NULL);
+		status = dmaengine_async_is_tx_complete(chan, cookie);
  		if (time_after_eq(jiffies, dma_sync_wait_timeout)) {
  			dev_err(chan->device->dev, "%s: timeout!\n", __func__);
  			return DMA_ERROR;
diff --git a/drivers/dma/dmatest.c b/drivers/dma/dmatest.c
index 9fe2ae7943169..dde7b9b626336 100644
--- a/drivers/dma/dmatest.c
+++ b/drivers/dma/dmatest.c
@@ -831,8 +831,7 @@ static int dmatest_func(void *data)
  					done->done,
  					msecs_to_jiffies(params->timeout));
  
-			status = dma_async_is_tx_complete(chan, cookie, NULL,
-							  NULL);
+			status = dmaengine_async_is_tx_complete(chan, cookie);
  		}
  
  		if (!done->done) {
diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h
index 5ae881729b620..0ee21887b3924 100644
--- a/include/linux/dmaengine.h
+++ b/include/linux/dmaengine.h
@@ -1426,6 +1426,8 @@ 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
   *
+ * Note: This is deprecated. Use dmaengine_async_is_tx_complete instead.
+ *
   * If @last and @used are passed in, upon return they reflect the most
   * recently submitted (used) cookie and the most recently completed
   * cookie.
@@ -1444,6 +1446,20 @@ static inline enum dma_status dma_async_is_tx_complete(struct dma_chan *chan,
  	return status;
  }
  
+/**
+ * dmaengine_async_is_tx_complete - poll for transaction completion
+ * @chan: DMA channel
+ * @cookie: transaction identifier to check status of
+ *
+ */
+static inline enum dma_status dmaengine_async_is_tx_complete(struct dma_chan *chan,
+	dma_cookie_t cookie)
+{
+	struct dma_tx_state state;
+
+	return chan->device->device_tx_status(chan, cookie, &state);
+}
+
  #ifdef CONFIG_DMA_ENGINE
  struct dma_chan *dma_find_channel(enum dma_transaction_type tx_type);
  enum dma_status dma_sync_wait(struct dma_chan *chan, dma_cookie_t cookie);
--
2.37.1








