From 0092a1e3f7636ff4e202a41b0320690699247e22 Mon Sep 17 00:00:00 2001
From: Loic Poulain <loic.poulain@linaro.org>
Date: Mon, 2 Aug 2021 10:42:46 +0530
Subject: [PATCH] bus: mhi: Add inbound buffers allocation flag
Git-commit: 0092a1e3f7636ff4e202a41b0320690699247e22
Patch-mainline: v5.15-rc1
References: bsc#1206451

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.

Link: https://lore.kernel.org/r/1624566520-20406-1-git-send-email-loic.poulain@linaro.org
Tested-by: Bhaumik Bhatt <bbhatt@codeaurora.org>
Reviewed-by: Bhaumik Bhatt <bbhatt@codeaurora.org>
Reviewed-by: Hemant Kumar <hemantk@codeaurora.org>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@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/20210802051255.5771-2-manivannan.sadhasivam@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/bus/mhi/core/internal.h  |    2 +-
 drivers/bus/mhi/core/main.c      |    9 ++++++---
 drivers/net/mhi/net.c            |    2 +-
 drivers/net/wwan/mhi_wwan_ctrl.c |    2 +-
 include/linux/mhi.h              |    7 ++++++-
 net/qrtr/mhi.c                   |    2 +-
 6 files changed, 16 insertions(+), 8 deletions(-)

--- a/drivers/bus/mhi/core/internal.h
+++ b/drivers/bus/mhi/core/internal.h
@@ -682,7 +682,7 @@ void mhi_rddm_prepare(struct mhi_control
 		      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, 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,
--- a/drivers/bus/mhi/core/main.c
+++ b/drivers/bus/mhi/core/main.c
@@ -1430,7 +1430,7 @@ exit_unprepare_channel:
 }
 
 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_contr
 	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,
@@ -1610,7 +1613,7 @@ void mhi_reset_chan(struct mhi_controlle
 }
 
 /* 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, unsigned int flags)
 {
 	int ret, dir;
 	struct mhi_controller *mhi_cntrl = mhi_dev->mhi_cntrl;
@@ -1621,7 +1624,7 @@ int mhi_prepare_for_transfer(struct mhi_
 		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;
 	}
--- a/drivers/net/mhi/net.c
+++ b/drivers/net/mhi/net.c
@@ -336,7 +336,7 @@ static int mhi_net_newlink(void *ctxt, s
 	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;
 
--- a/drivers/net/wwan/mhi_wwan_ctrl.c
+++ b/drivers/net/wwan/mhi_wwan_ctrl.c
@@ -110,7 +110,7 @@ static int mhi_wwan_ctrl_start(struct ww
 	int ret;
 
 	/* Start mhi device's channel(s) */
-	ret = mhi_prepare_for_transfer(mhiwwan->mhi_dev);
+	ret = mhi_prepare_for_transfer(mhiwwan->mhi_dev, 0);
 	if (ret)
 		return ret;
 
--- a/include/linux/mhi.h
+++ b/include/linux/mhi.h
@@ -721,8 +721,13 @@ void mhi_device_put(struct mhi_device *m
  *                            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,
+			     unsigned int flags);
+
+/* Automatically allocate and queue inbound buffers */
+#define MHI_CH_INBOUND_ALLOC_BUFS BIT(0)
 
 /**
  * mhi_unprepare_from_transfer - Reset UL and DL channels for data transfer.
--- a/net/qrtr/mhi.c
+++ b/net/qrtr/mhi.c
@@ -79,7 +79,7 @@ static int qcom_mhi_qrtr_probe(struct mh
 	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;