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Commit 9219c292 authored by Sujeev Dias's avatar Sujeev Dias
Browse files

mhi: core: add support for bi-direction or directionless channels 



MHI channels are not always unidirectional. Some offload
channels are either bi-directional or has no direction
associate with it, add support for such channels.

CRs-Fixed: 2229699
Change-Id: I6cb3b879eb3d90e9bbf8704805a16f1b43306e0d
Signed-off-by: default avatarSujeev Dias <sdias@codeaurora.org>
parent 3ddce5d8

Documentation/devicetree/bindings/bus/mhi.txt

+2 −0
Original line number Diff line number Diff line
@@ -22,8 +22,10 @@ Main node properties: 
	2nd element: Transfer ring length in elements

	3rd element: Event ring associated with this channel

	4th element: Channel direction as defined by enum dma_data_direction

		0 = Bidirectional data transfer

		1 = UL data transfer

		2 = DL data transfer

		3 = No direction, not a regular data transfer channel

	5th element: Channel doorbell mode configuration as defined by

	enum MHI_BRSTMODE

		2 = burst mode disabled

drivers/bus/mhi/core/mhi_init.c

+18 −1
Original line number Diff line number Diff line
@@ -616,7 +616,19 @@ int mhi_device_configure(struct mhi_device *mhi_dev, 
	struct mhi_chan_ctxt *ch_ctxt;

	int er_index, chan;



	mhi_chan = (dir == DMA_TO_DEVICE) ? mhi_dev->ul_chan : mhi_dev->dl_chan;

	switch (dir) {

	case DMA_TO_DEVICE:

		mhi_chan = mhi_dev->ul_chan;

		break;

	case DMA_BIDIRECTIONAL:

	case DMA_FROM_DEVICE:

	case DMA_NONE:

		mhi_chan = mhi_dev->dl_chan;

		break;

	default:

		return -EINVAL;

	}



	er_index = mhi_chan->er_index;

	chan = mhi_chan->chan;
@@ -830,6 +842,11 @@ static int of_parse_ch_cfg(struct mhi_controller *mhi_cntrl, 
		     mhi_chan->xfer_type != MHI_XFER_BUFFER))

			goto error_chan_cfg;



		/* bi-dir and dirctionless channels must be a offload chan */

		if ((mhi_chan->dir == DMA_BIDIRECTIONAL ||

		     mhi_chan->dir == DMA_NONE) && !mhi_chan->offload_ch)

			goto error_chan_cfg;



		/* if mhi host allocate the buffers then client cannot queue */

		if (mhi_chan->pre_alloc)

			mhi_chan->queue_xfer = mhi_queue_nop;

drivers/bus/mhi/core/mhi_main.c

+8 −2
Original line number Diff line number Diff line
@@ -525,12 +525,18 @@ void mhi_create_devices(struct mhi_controller *mhi_cntrl) 
		if (!mhi_dev)

			return;



		if (mhi_chan->dir == DMA_TO_DEVICE) {

		switch (mhi_chan->dir) {

		case DMA_TO_DEVICE:

			mhi_dev->ul_chan = mhi_chan;

			mhi_dev->ul_chan_id = mhi_chan->chan;

			mhi_dev->ul_xfer = mhi_chan->queue_xfer;

			mhi_dev->ul_event_id = mhi_chan->er_index;

		} else {

			break;

		case DMA_NONE:

		case DMA_BIDIRECTIONAL:

			mhi_dev->ul_chan_id = mhi_chan->chan;

		case DMA_FROM_DEVICE:

			/* we use dl_chan for offload channels */

			mhi_dev->dl_chan = mhi_chan;

			mhi_dev->dl_chan_id = mhi_chan->chan;

			mhi_dev->dl_xfer = mhi_chan->queue_xfer;