[RESEND 03/10] dmaengine: Remove the last, used parameters in dma_async_is_tx_complete

[Ben Walker <benjamin.walker@intel.com>]

These are only used by a single driver (pxa_camera) which knows exactly
which DMA engine it is dealing with and therefore knows the behavior
of the cookie values. It can grab the value it needs directly from
the dma_chan instead. No other DMA client assumes anything about
the behavior of the cookie values, so the cookie becomes an opaque
handle after this patch.

Signed-off-by: Ben Walker <benjamin.walker@intel.com>
---
 Documentation/driver-api/dmaengine/client.rst  | 17 +++--------------
 .../driver-api/dmaengine/provider.rst          |  6 +++---
 drivers/crypto/stm32/stm32-hash.c              |  3 +--
 drivers/dma/dmaengine.c                        |  2 +-
 drivers/dma/dmatest.c                          |  3 +--
 drivers/media/platform/omap/omap_vout_vrfb.c   |  2 +-
 drivers/media/platform/pxa_camera.c            | 13 +++++++++++--
 drivers/rapidio/devices/rio_mport_cdev.c       |  3 +--
 include/linux/dmaengine.h                      | 18 +++---------------
 9 files changed, 25 insertions(+), 42 deletions(-)

diff --git a/Documentation/driver-api/dmaengine/client.rst b/Documentation/driver-api/dmaengine/client.rst
index 85ecec2c40005..6e43c9c428e68 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 dma_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.
@@ -340,22 +340,11 @@ 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.
+		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 0072c9c7efd34..e9e9de18d6b02 100644
--- a/Documentation/driver-api/dmaengine/provider.rst
+++ b/Documentation/driver-api/dmaengine/provider.rst
@@ -543,10 +543,10 @@ 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/crypto/stm32/stm32-hash.c b/drivers/crypto/stm32/stm32-hash.c
index d33006d43f761..9c3b6526e39f8 100644
--- a/drivers/crypto/stm32/stm32-hash.c
+++ b/drivers/crypto/stm32/stm32-hash.c
@@ -453,8 +453,7 @@ static int stm32_hash_xmit_dma(struct stm32_hash_dev *hdev,
 					 msecs_to_jiffies(100)))
 		err = -ETIMEDOUT;
 
-	if (dma_async_is_tx_complete(hdev->dma_lch, cookie,
-				     NULL, NULL) != DMA_COMPLETE)
+	if (dma_async_is_tx_complete(hdev->dma_lch, cookie) != DMA_COMPLETE)
 		err = -ETIMEDOUT;
 
 	if (err) {
diff --git a/drivers/dma/dmaengine.c b/drivers/dma/dmaengine.c
index 2cfa8458b51be..590f238a0671a 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 = dma_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 f696246f57fdb..0574090a80c8c 100644
--- a/drivers/dma/dmatest.c
+++ b/drivers/dma/dmatest.c
@@ -832,8 +832,7 @@ static int dmatest_func(void *data)
 					done->done,
 					msecs_to_jiffies(params->timeout));
 
-			status = dma_async_is_tx_complete(chan, cookie, NULL,
-							  NULL);
+			status = dma_async_is_tx_complete(chan, cookie);
 		}
 
 		if (!done->done) {
diff --git a/drivers/media/platform/omap/omap_vout_vrfb.c b/drivers/media/platform/omap/omap_vout_vrfb.c
index 0cfa0169875f0..d762939ffa5de 100644
--- a/drivers/media/platform/omap/omap_vout_vrfb.c
+++ b/drivers/media/platform/omap/omap_vout_vrfb.c
@@ -289,7 +289,7 @@ int omap_vout_prepare_vrfb(struct omap_vout_device *vout,
 					 vout->vrfb_dma_tx.tx_status == 1,
 					 VRFB_TX_TIMEOUT);
 
-	status = dma_async_is_tx_complete(chan, cookie, NULL, NULL);
+	status = dma_async_is_tx_complete(chan, cookie);
 
 	if (vout->vrfb_dma_tx.tx_status == 0) {
 		pr_err("%s: Timeout while waiting for DMA\n", __func__);
diff --git a/drivers/media/platform/pxa_camera.c b/drivers/media/platform/pxa_camera.c
index 3ba00b0f93200..6d5c36ea6622a 100644
--- a/drivers/media/platform/pxa_camera.c
+++ b/drivers/media/platform/pxa_camera.c
@@ -1049,8 +1049,17 @@ static void pxa_camera_dma_irq(struct pxa_camera_dev *pcdev,
 	last_buf = list_entry(pcdev->capture.prev,
 			      struct pxa_buffer, queue);
 	last_status = dma_async_is_tx_complete(pcdev->dma_chans[chan],
-					       last_buf->cookie[chan],
-					       NULL, &last_issued);
+					       last_buf->cookie[chan]);
+	/*
+	 * Peek into the channel and read the last cookie that was issued.
+	 * This is a layering violation - the dmaengine API does not officially
+	 * provide this information. Since this camera driver is tightly coupled
+	 * with a specific DMA device we know exactly how this cookie value will
+	 * behave. Otherwise, this wouldn't be safe.
+	 */
+	last_issued = pcdev->dma_chans[chan]->cookie;
+	barrier();
+
 	if (camera_status & overrun &&
 	    last_status != DMA_COMPLETE) {
 		dev_dbg(pcdev_to_dev(pcdev), "FIFO overrun! CISR: %x\n",
diff --git a/drivers/rapidio/devices/rio_mport_cdev.c b/drivers/rapidio/devices/rio_mport_cdev.c
index 7df466e222820..790e0c7a3306c 100644
--- a/drivers/rapidio/devices/rio_mport_cdev.c
+++ b/drivers/rapidio/devices/rio_mport_cdev.c
@@ -597,8 +597,7 @@ static void dma_xfer_callback(void *param)
 	struct mport_dma_req *req = (struct mport_dma_req *)param;
 	struct mport_cdev_priv *priv = req->priv;
 
-	req->status = dma_async_is_tx_complete(priv->dmach, req->cookie,
-					       NULL, NULL);
+	req->status = dma_async_is_tx_complete(priv->dmach, req->cookie);
 	complete(&req->req_comp);
 	kref_put(&req->refcount, dma_req_free);
 }
diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h
index 8c4934bc038ec..5f884fffe74cc 100644
--- a/include/linux/dmaengine.h
+++ b/include/linux/dmaengine.h
@@ -1436,25 +1436,13 @@ static inline void dma_async_issue_pending(struct dma_chan *chan)
  * dma_async_is_tx_complete - poll for transaction completion
  * @chan: DMA channel
  * @cookie: transaction identifier to check status of
- * @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 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)
+	dma_cookie_t cookie)
 {
 	struct dma_tx_state state;
-	enum dma_status status;
-
-	status = chan->device->device_tx_status(chan, cookie, &state);
-	if (last)
-		*last = state.last;
-	if (used)
-		*used = state.used;
-	return status;
+
+	return chan->device->device_tx_status(chan, cookie, &state);
 }
 
 #ifdef CONFIG_DMA_ENGINE
-- 
2.33.1