Commit 570829fb authored Nov 24, 2021 by Veerabhadrarao Badiganti

msm: mhi_dev: Don't process any other interrupts during M0 processing

M0 (mhi resume) processing and doorbell interrupt processing are done
in different contexts. And there can be a chance that DB processing
can proceed even before the resume is completely done.

Say while processing M0, MHI has issued M0-ack but not updated channel
state to running state for *all* channels yet. The host can start ringing
DB the moment it sees M0-ack and it's the channel is in running state.

To avoid this race condition, ensure MHI doesn't process any CHDB
interrupt until it's completely done with the resume.

Change-Id: Ie8f7fec034be6b17c71e3b7437ab8e6effb63365
Signed-off-by: Veerabhadrarao Badiganti <quic_vbadigan@quicinc.com>

parent 97db20de

drivers/platform/msm/mhi_dev/mhi_sm.c

+11 −0

Original line number	Diff line number	Diff line
		@@ -1338,6 +1338,17 @@ int mhi_dev_notify_sm_event(enum mhi_dev_event event)
		INIT_WORK(&state_change_event->work, mhi_sm_dev_event_manager);
		atomic_inc(&mhi_sm_ctx->pending_device_events);
		queue_work(mhi_sm_ctx->mhi_sm_wq, &state_change_event->work);

		/*
		* Wait until M0 processing is completely done.
		* This ensures CHDB won't get processed while resume is in
		* progress thus avoids race between M0 and CHDB processing.
		*/
		if (event == MHI_DEV_EVENT_M0_STATE) {
		MHI_SM_DBG("Got M0, wait until resume is done\n");
		flush_workqueue(mhi_sm_ctx->mhi_sm_wq);
		}

		res = 0;

		exit: