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From:   Qiang Yu <quic_qianyu@quicinc.com>
To:     mani@kernel.org, loic.poulain@linaro.org
Cc:     mhi@lists.linux.dev, linux-arm-msm@vger.kernel.org,
        linux-kernel@vger.kernel.org, quic_cang@quicinc.com,
        mrana@quicinc.com, Qiang Yu <quic_qianyu@quicinc.com>
Subject: [PATCH] bus: mhi: host: Disable preemption while processing data events
Date:   Thu,  3 Nov 2022 15:55:11 +0800
Message-Id: <1667462111-55496-1-git-send-email-quic_qianyu@quicinc.com>
Precedence: bulk

If data processing of an event is scheduled out because core
is busy handling multiple irqs, this can starves the processing
of MHI M0 state change event on another core. Fix this issue by
disabling irq on the core processing data events.

Signed-off-by: Qiang Yu <quic_qianyu@quicinc.com>
---
 drivers/bus/mhi/host/main.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/bus/mhi/host/main.c b/drivers/bus/mhi/host/main.c
index f3aef77a..b58698d 100644
--- a/drivers/bus/mhi/host/main.c
+++ b/drivers/bus/mhi/host/main.c
@@ -1027,13 +1027,14 @@ int mhi_process_data_event_ring(struct mhi_controller *mhi_cntrl,
 
 void mhi_ev_task(unsigned long data)
 {
+	unsigned long flags;
 	struct mhi_event *mhi_event = (struct mhi_event *)data;
 	struct mhi_controller *mhi_cntrl = mhi_event->mhi_cntrl;
 
 	/* process all pending events */
-	spin_lock_bh(&mhi_event->lock);
+	spin_lock_irqsave(&mhi_event->lock, flags);
 	mhi_event->process_event(mhi_cntrl, mhi_event, U32_MAX);
-	spin_unlock_bh(&mhi_event->lock);
+	spin_unlock_irqrestore(&mhi_event->lock, flags);
 }
 
 void mhi_ctrl_ev_task(unsigned long data)
-- 
2.7.4