1 files changed, 78 insertions, 0 deletions

diff --git a/drivers/bus/mhi/ep/main.c b/drivers/bus/mhi/ep/main.c
index 20d579733486..968025e4d3ac 100644
--- a/drivers/bus/mhi/ep/main.c
+++ b/drivers/bus/mhi/ep/main.c
@@ -22,6 +22,8 @@
 
 static DEFINE_IDA(mhi_ep_cntrl_ida);
 
+static int mhi_ep_destroy_device(struct device *dev, void *data);
+
 static int mhi_ep_send_event(struct mhi_ep_cntrl *mhi_cntrl, u32 ring_idx,
 			     struct mhi_ring_element *el, bool bei)
 {
@@ -400,6 +402,68 @@ static irqreturn_t mhi_ep_irq(int irq, void *data)
 	return IRQ_HANDLED;
 }
 
+static void mhi_ep_abort_transfer(struct mhi_ep_cntrl *mhi_cntrl)
+{
+	struct mhi_ep_ring *ch_ring, *ev_ring;
+	struct mhi_result result = {};
+	struct mhi_ep_chan *mhi_chan;
+	int i;
+
+	/* Stop all the channels */
+	for (i = 0; i < mhi_cntrl->max_chan; i++) {
+		mhi_chan = &mhi_cntrl->mhi_chan[i];
+		if (!mhi_chan->ring.started)
+			continue;
+
+		mutex_lock(&mhi_chan->lock);
+		/* Send channel disconnect status to client drivers */
+		if (mhi_chan->xfer_cb) {
+			result.transaction_status = -ENOTCONN;
+			result.bytes_xferd = 0;
+			mhi_chan->xfer_cb(mhi_chan->mhi_dev, &result);
+		}
+
+		mhi_chan->state = MHI_CH_STATE_DISABLED;
+		mutex_unlock(&mhi_chan->lock);
+	}
+
+	flush_workqueue(mhi_cntrl->wq);
+
+	/* Destroy devices associated with all channels */
+	device_for_each_child(&mhi_cntrl->mhi_dev->dev, NULL, mhi_ep_destroy_device);
+
+	/* Stop and reset the transfer rings */
+	for (i = 0; i < mhi_cntrl->max_chan; i++) {
+		mhi_chan = &mhi_cntrl->mhi_chan[i];
+		if (!mhi_chan->ring.started)
+			continue;
+
+		ch_ring = &mhi_cntrl->mhi_chan[i].ring;
+		mutex_lock(&mhi_chan->lock);
+		mhi_ep_ring_reset(mhi_cntrl, ch_ring);
+		mutex_unlock(&mhi_chan->lock);
+	}
+
+	/* Stop and reset the event rings */
+	for (i = 0; i < mhi_cntrl->event_rings; i++) {
+		ev_ring = &mhi_cntrl->mhi_event[i].ring;
+		if (!ev_ring->started)
+			continue;
+
+		mutex_lock(&mhi_cntrl->event_lock);
+		mhi_ep_ring_reset(mhi_cntrl, ev_ring);
+		mutex_unlock(&mhi_cntrl->event_lock);
+	}
+
+	/* Stop and reset the command ring */
+	mhi_ep_ring_reset(mhi_cntrl, &mhi_cntrl->mhi_cmd->ring);
+
+	mhi_ep_free_host_cfg(mhi_cntrl);
+	mhi_ep_mmio_mask_interrupts(mhi_cntrl);
+
+	mhi_cntrl->enabled = false;
+}
+
 int mhi_ep_power_up(struct mhi_ep_cntrl *mhi_cntrl)
 {
 	struct device *dev = &mhi_cntrl->mhi_dev->dev;
@@ -454,6 +518,16 @@ err_free_event:
 }
 EXPORT_SYMBOL_GPL(mhi_ep_power_up);
 
+void mhi_ep_power_down(struct mhi_ep_cntrl *mhi_cntrl)
+{
+	if (mhi_cntrl->enabled)
+		mhi_ep_abort_transfer(mhi_cntrl);
+
+	kfree(mhi_cntrl->mhi_event);
+	disable_irq(mhi_cntrl->irq);
+}
+EXPORT_SYMBOL_GPL(mhi_ep_power_down);
+
 static void mhi_ep_release_device(struct device *dev)
 {
 	struct mhi_ep_device *mhi_dev = to_mhi_ep_device(dev);
@@ -733,6 +807,10 @@ err_free_ch:
 }
 EXPORT_SYMBOL_GPL(mhi_ep_register_controller);
 
+/*
+ * It is expected that the controller drivers will power down the MHI EP stack
+ * using "mhi_ep_power_down()" before calling this function to unregister themselves.
+ */
 void mhi_ep_unregister_controller(struct mhi_ep_cntrl *mhi_cntrl)
 {
 	struct mhi_ep_device *mhi_dev = mhi_cntrl->mhi_dev;