bus: mhi: core: Add an API for auto queueing buffers for DL channel

Add a new API "mhi_prepare_for_transfer_autoqueue" for using with client drivers like QRTR to request MHI core to autoqueue buffers for the DL channel along with starting both UL and DL channels. So far, the "auto_queue" flag specified by the controller drivers in channel definition served this purpose but this will be removed at some point in future. Cc: [email protected] Cc: Jakub Kicinski <[email protected]> Cc: David S. Miller <[email protected]> Cc: Greg Kroah-Hartman <[email protected]> Co-developed-by: Loic Poulain <[email protected]> Acked-by: Jakub Kicinski <[email protected]> Signed-off-by: Loic Poulain <[email protected]> Signed-off-by: Manivannan Sadhasivam <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Greg Kroah-Hartman <[email protected]>
chewitt · Dec 17, 2021 · 227fee5 · 227fee5
1 parent d651ce8
commit 227fee5
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Showing 4 changed files with 39 additions and 11 deletions.
diff --git a/drivers/bus/mhi/core/internal.h b/drivers/bus/mhi/core/internal.h
@@ -682,8 +682,12 @@ void mhi_deinit_free_irq(struct mhi_controller *mhi_cntrl);
 void mhi_rddm_prepare(struct mhi_controller *mhi_cntrl,
 		      struct image_info *img_info);
 void mhi_fw_load_handler(struct mhi_controller *mhi_cntrl);
+
+/* Automatically allocate and queue inbound buffers */
+#define MHI_CH_INBOUND_ALLOC_BUFS BIT(0)
 int mhi_prepare_channel(struct mhi_controller *mhi_cntrl,
-			struct mhi_chan *mhi_chan);
+			struct mhi_chan *mhi_chan, unsigned int flags);
+
 int mhi_init_chan_ctxt(struct mhi_controller *mhi_cntrl,
 		       struct mhi_chan *mhi_chan);
 void mhi_deinit_chan_ctxt(struct mhi_controller *mhi_cntrl,

diff --git a/drivers/bus/mhi/core/main.c b/drivers/bus/mhi/core/main.c
@@ -1430,7 +1430,7 @@ static void mhi_unprepare_channel(struct mhi_controller *mhi_cntrl,
 }
 
 int mhi_prepare_channel(struct mhi_controller *mhi_cntrl,
-			struct mhi_chan *mhi_chan)
+			struct mhi_chan *mhi_chan, unsigned int flags)
 {
 	int ret = 0;
 	struct device *dev = &mhi_chan->mhi_dev->dev;
@@ -1455,6 +1455,9 @@ int mhi_prepare_channel(struct mhi_controller *mhi_cntrl,
 	if (ret)
 		goto error_pm_state;
 
+	if (mhi_chan->dir == DMA_FROM_DEVICE)
+		mhi_chan->pre_alloc = !!(flags & MHI_CH_INBOUND_ALLOC_BUFS);
+
 	/* Pre-allocate buffer for xfer ring */
 	if (mhi_chan->pre_alloc) {
 		int nr_el = get_nr_avail_ring_elements(mhi_cntrl,
@@ -1610,8 +1613,7 @@ void mhi_reset_chan(struct mhi_controller *mhi_cntrl, struct mhi_chan *mhi_chan)
 	read_unlock_bh(&mhi_cntrl->pm_lock);
 }
 
-/* Move channel to start state */
-int mhi_prepare_for_transfer(struct mhi_device *mhi_dev)
+static int __mhi_prepare_for_transfer(struct mhi_device *mhi_dev, unsigned int flags)
 {
 	int ret, dir;
 	struct mhi_controller *mhi_cntrl = mhi_dev->mhi_cntrl;
@@ -1622,7 +1624,7 @@ int mhi_prepare_for_transfer(struct mhi_device *mhi_dev)
 		if (!mhi_chan)
 			continue;
 
-		ret = mhi_prepare_channel(mhi_cntrl, mhi_chan);
+		ret = mhi_prepare_channel(mhi_cntrl, mhi_chan, flags);
 		if (ret)
 			goto error_open_chan;
 	}
@@ -1640,8 +1642,19 @@ int mhi_prepare_for_transfer(struct mhi_device *mhi_dev)
 
 	return ret;
 }
+
+int mhi_prepare_for_transfer(struct mhi_device *mhi_dev)
+{
+	return __mhi_prepare_for_transfer(mhi_dev, 0);
+}
 EXPORT_SYMBOL_GPL(mhi_prepare_for_transfer);
 
+int mhi_prepare_for_transfer_autoqueue(struct mhi_device *mhi_dev)
+{
+	return __mhi_prepare_for_transfer(mhi_dev, MHI_CH_INBOUND_ALLOC_BUFS);
+}
+EXPORT_SYMBOL_GPL(mhi_prepare_for_transfer_autoqueue);
+
 void mhi_unprepare_from_transfer(struct mhi_device *mhi_dev)
 {
 	struct mhi_controller *mhi_cntrl = mhi_dev->mhi_cntrl;

diff --git a/include/linux/mhi.h b/include/linux/mhi.h
@@ -730,15 +730,26 @@ void mhi_device_put(struct mhi_device *mhi_dev);
 
 /**
  * mhi_prepare_for_transfer - Setup UL and DL channels for data transfer.
- *                            Allocate and initialize the channel context and
- *                            also issue the START channel command to both
- *                            channels. Channels can be started only if both
- *                            host and device execution environments match and
- *                            channels are in a DISABLED state.
  * @mhi_dev: Device associated with the channels
+ *
+ * Allocate and initialize the channel context and also issue the START channel
+ * command to both channels. Channels can be started only if both host and
+ * device execution environments match and channels are in a DISABLED state.
  */
 int mhi_prepare_for_transfer(struct mhi_device *mhi_dev);
 
+/**
+ * mhi_prepare_for_transfer_autoqueue - Setup UL and DL channels with auto queue
+ *                                      buffers for DL traffic
+ * @mhi_dev: Device associated with the channels
+ *
+ * Allocate and initialize the channel context and also issue the START channel
+ * command to both channels. Channels can be started only if both host and
+ * device execution environments match and channels are in a DISABLED state.
+ * The MHI core will automatically allocate and queue buffers for the DL traffic.
+ */
+int mhi_prepare_for_transfer_autoqueue(struct mhi_device *mhi_dev);
+
 /**
  * mhi_unprepare_from_transfer - Reset UL and DL channels for data transfer.
  *                               Issue the RESET channel command and let the

diff --git a/net/qrtr/mhi.c b/net/qrtr/mhi.c
@@ -79,7 +79,7 @@ static int qcom_mhi_qrtr_probe(struct mhi_device *mhi_dev,
 	int rc;
 
 	/* start channels */
-	rc = mhi_prepare_for_transfer(mhi_dev);
+	rc = mhi_prepare_for_transfer_autoqueue(mhi_dev);
 	if (rc)
 		return rc;