[v4,6/8] bus: mhi: core: Check channel execution environment before issuing reset

Commit Message

Bhaumik Bhatt Dec. 4, 2020, 1:23 a.m. UTC

A client can attempt to unprepare certain channels for transfer even
after the execution environment they are supposed to run in has changed.
In the event that happens, the device need not be notified of the reset
and the host can proceed with clean up for the channel context and
memory allocated for it on the host as the device will no longer be able
to respond to such a request.

Signed-off-by: Bhaumik Bhatt <[e-mail]>
Reviewed-by: Hemant Kumar <[e-mail]>
---
 drivers/bus/mhi/core/main.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)

Patch

diff --git a/drivers/bus/mhi/core/main.c b/drivers/bus/mhi/core/main.c
index 064f313..f4026af 100644
--- a/drivers/bus/mhi/core/main.c
+++ b/drivers/bus/mhi/core/main.c
@@ -1320,11 +1320,24 @@  static void __mhi_unprepare_channel(struct mhi_controller *mhi_cntrl,
 	/* no more processing events for this channel */
 	mutex_lock(&mhi_chan->mutex);
 
+	if (!(BIT(mhi_cntrl->ee) & mhi_chan->ee_mask)) {
+		dev_err(dev,
+			"Current EE: %s Required EE Mask: 0x%x for chan: %s\n",
+			TO_MHI_EXEC_STR(mhi_cntrl->ee), mhi_chan->ee_mask,
+			mhi_chan->name);
+		goto exit_unprepare_channel;
+	}
+
 	ret = mhi_update_channel_state(mhi_cntrl, mhi_chan,
 				       MHI_CH_STATE_TYPE_RESET);
 	if (ret)
 		dev_err(dev, "Failed to reset channel, still resetting\n");
 
+exit_unprepare_channel:
+	write_lock_irq(&mhi_chan->lock);
+	mhi_chan->ch_state = MHI_CH_STATE_DISABLED;
+	write_unlock_irq(&mhi_chan->lock);
+
 	if (!mhi_chan->offload_ch) {
 		mhi_reset_chan(mhi_cntrl, mhi_chan);
 		mhi_deinit_chan_ctxt(mhi_cntrl, mhi_chan);