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Commit 3ddce5d8 authored by Sujeev Dias's avatar Sujeev Dias
Browse files

mhi: core: prepare all the descriptors before ringing hardware doorbell 



While mhi host queues new buffers to transfer ring during
start, process completion transfer thread will queue a
buffer to same channel after receiving a completion
event. To avoid this scenario, prepare all descriptors
before ringing the hardware doorbell so there will not be
any completion packets to process.

CRs-Fixed: 2236500
Change-Id: I91f065932ef46dc3520fd1a8ad634e2b65badff1
Signed-off-by: default avatarSujeev Dias <sdias@codeaurora.org>
parent 8c5ca64d

drivers/bus/mhi/core/mhi_main.c

+21 −8
Original line number Diff line number Diff line
@@ -1101,13 +1101,8 @@ static int __mhi_prepare_channel(struct mhi_controller *mhi_cntrl, 
	mhi_chan->ch_state = MHI_CH_STATE_ENABLED;

	write_unlock_irq(&mhi_chan->lock);



	read_lock_bh(&mhi_cntrl->pm_lock);

	mhi_cntrl->wake_put(mhi_cntrl, false);

	read_unlock_bh(&mhi_cntrl->pm_lock);



	/* pre allocate buffer for xfer ring */

	if (mhi_chan->pre_alloc) {

		struct mhi_device *mhi_dev = mhi_chan->mhi_dev;

		int nr_el = get_nr_avail_ring_elements(mhi_cntrl,

						       &mhi_chan->tre_ring);
@@ -1120,17 +1115,30 @@ static int __mhi_prepare_channel(struct mhi_controller *mhi_cntrl, 
				goto error_pre_alloc;

			}



			ret = mhi_queue_buf(mhi_dev, mhi_chan, buf, MHI_MAX_MTU,

					    MHI_EOT);

			/* prepare transfer descriptors */

			ret = mhi_chan->gen_tre(mhi_cntrl, mhi_chan, buf, buf,

						MHI_MAX_MTU, MHI_EOT);

			if (ret) {

				MHI_ERR("Chan:%d error queue buffer\n",

				MHI_ERR("Chan:%d error prepare buffer\n",

					mhi_chan->chan);

				kfree(buf);

				goto error_pre_alloc;

			}

		}



		read_lock_bh(&mhi_cntrl->pm_lock);

		if (MHI_DB_ACCESS_VALID(mhi_cntrl->pm_state)) {

			read_lock_irq(&mhi_chan->lock);

			mhi_ring_chan_db(mhi_cntrl, mhi_chan);

			read_unlock_irq(&mhi_chan->lock);

		}

		read_unlock_bh(&mhi_cntrl->pm_lock);

	}



	read_lock_bh(&mhi_cntrl->pm_lock);

	mhi_cntrl->wake_put(mhi_cntrl, false);

	read_unlock_bh(&mhi_cntrl->pm_lock);



	mutex_unlock(&mhi_chan->mutex);



	MHI_LOG("Chan:%d successfully moved to start state\n", mhi_chan->chan);
@@ -1152,6 +1160,11 @@ static int __mhi_prepare_channel(struct mhi_controller *mhi_cntrl, 
	return ret;



error_pre_alloc:



	read_lock_bh(&mhi_cntrl->pm_lock);

	mhi_cntrl->wake_put(mhi_cntrl, false);

	read_unlock_bh(&mhi_cntrl->pm_lock);



	mutex_unlock(&mhi_chan->mutex);

	__mhi_unprepare_channel(mhi_cntrl, mhi_chan);