bus: mhi: Add inbound buffers allocation flag

Currently, the MHI controller driver defines which channels should
have their inbound buffers allocated and queued. But ideally, this is
something that should be decided by the MHI device driver instead,
which actually deals with that buffers.

Add a flag parameter to mhi_prepare_for_transfer allowing to specify
if buffers have to be allocated and queued by the MHI stack.

Keep auto_queue flag for now, but should be removed at some point.

Signed-off-by: Loic Poulain <loic.poulain@linaro.org>

5 files changed, 22 insertions, 7 deletions

diff --git a/drivers/bus/mhi/core/internal.h b/drivers/bus/mhi/core/internal.h
index 5b9ea66b92dc..672052fe3b44 100644
--- a/drivers/bus/mhi/core/internal.h
+++ b/drivers/bus/mhi/core/internal.h
@@ -682,7 +682,7 @@ void mhi_rddm_prepare(struct mhi_controller *mhi_cntrl,
 		      struct image_info *img_info);
 void mhi_fw_load_handler(struct mhi_controller *mhi_cntrl);
 int mhi_prepare_channel(struct mhi_controller *mhi_cntrl,
-			struct mhi_chan *mhi_chan);
+			struct mhi_chan *mhi_chan, enum mhi_chan_flags 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
index 22acde118bc3..c8b6dcce897c 100644
--- a/drivers/bus/mhi/core/main.c
+++ b/drivers/bus/mhi/core/main.c
@@ -1423,7 +1423,8 @@ exit_unprepare_channel:
 }
 
 int mhi_prepare_channel(struct mhi_controller *mhi_cntrl,
-			struct mhi_chan *mhi_chan)
+			struct mhi_chan *mhi_chan,
+			enum mhi_chan_flags flags)
 {
 	int ret = 0;
 	struct device *dev = &mhi_chan->mhi_dev->dev;
@@ -1448,6 +1449,9 @@ 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,
@@ -1603,7 +1607,8 @@ void mhi_reset_chan(struct mhi_controller *mhi_cntrl, struct mhi_chan *mhi_chan)
 }
 
 /* Move channel to start state */
-int mhi_prepare_for_transfer(struct mhi_device *mhi_dev)
+int mhi_prepare_for_transfer(struct mhi_device *mhi_dev,
+			     enum mhi_chan_flags flags)
 {
 	int ret, dir;
 	struct mhi_controller *mhi_cntrl = mhi_dev->mhi_cntrl;
@@ -1614,7 +1619,7 @@ 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;
 	}
diff --git a/drivers/net/mhi/net.c b/drivers/net/mhi/net.c
index f59960876083..a838ad2e5353 100644
--- a/drivers/net/mhi/net.c
+++ b/drivers/net/mhi/net.c
@@ -325,7 +325,7 @@ static int mhi_net_probe(struct mhi_device *mhi_dev,
 	u64_stats_init(&mhi_netdev->stats.tx_syncp);
 
 	/* Start MHI channels */
-	err = mhi_prepare_for_transfer(mhi_dev);
+	err = mhi_prepare_for_transfer(mhi_dev, 0);
 	if (err)
 		goto out_err;
 
diff --git a/include/linux/mhi.h b/include/linux/mhi.h
index 944aa3aa3035..86cea5256e3c 100644
--- a/include/linux/mhi.h
+++ b/include/linux/mhi.h
@@ -60,6 +60,14 @@ enum mhi_flags {
 };
 
 /**
+ * enum mhi_chan_flags - MHI channel flags
+ * @MHI_CH_INBOUND_ALLOC_BUFS: Automatically allocate and queue inbound buffers
+ */
+enum mhi_chan_flags {
+	MHI_CH_INBOUND_ALLOC_BUFS = BIT(0),
+};
+
+/**
  * enum mhi_device_type - Device types
  * @MHI_DEVICE_XFER: Handles data transfer
  * @MHI_DEVICE_CONTROLLER: Control device
@@ -719,8 +727,10 @@ void mhi_device_put(struct mhi_device *mhi_dev);
  *                            host and device execution environments match and
  *                            channels are in a DISABLED state.
  * @mhi_dev: Device associated with the channels
+ * @flags: MHI channel flags
  */
-int mhi_prepare_for_transfer(struct mhi_device *mhi_dev);
+int mhi_prepare_for_transfer(struct mhi_device *mhi_dev,
+			     enum mhi_chan_flags flags);
 
 /**
  * mhi_unprepare_from_transfer - Reset UL and DL channels for data transfer.
diff --git a/net/qrtr/mhi.c b/net/qrtr/mhi.c
index 2bf2b1943e61..47afded9f588 100644
--- a/net/qrtr/mhi.c
+++ b/net/qrtr/mhi.c
@@ -77,7 +77,7 @@ 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(mhi_dev, MHI_CH_INBOUND_ALLOC_BUFS);
 	if (rc)
 		return rc;