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: netdev@vger.kernel.org
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: David S. Miller <davem@davemloft.net>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Co-developed-by: Loic Poulain <loic.poulain@linaro.org>
Acked-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Loic Poulain <loic.poulain@linaro.org>
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Link: https://lore.kernel.org/r/20211216081227.237749-9-manivannan.sadhasivam@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 16 insertions, 5 deletions

diff --git a/include/linux/mhi.h b/include/linux/mhi.h
index a5cc4cdf9cc8..a5441ad33c74 100644
--- a/include/linux/mhi.h
+++ b/include/linux/mhi.h
@@ -730,16 +730,27 @@ 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
  *                               device clean-up the context so no incoming