linux-kernel - [PATCH v2 1/1] bus: mhi: Disable IRQs instead of freeing them during power down

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Date:   Tue, 21 Jun 2022 16:38:09 +0800
From:   Qiang Yu <quic_qianyu@...cinc.com>
To:     <mani@...nel.org>, <quic_hemantk@...cinc.com>,
        <loic.poulain@...aro.org>, <quic_jhugo@...cinc.com>
CC:     <mhi@...ts.linux.dev>, <linux-arm-msm@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>, <quic_cang@...cinc.com>,
        Qiang Yu <quic_qianyu@...cinc.com>
Subject: [PATCH v2 1/1] bus: mhi: Disable IRQs instead of freeing them during power down

MHI device may go down several times while running. So we just do
disable/enable IRQs during the mhi_{power_down/power_up} time and
request/free them when the MHI driver gets installed and removed.

Signed-off-by: Qiang Yu <quic_qianyu@...cinc.com>
---
v1->v2: Rewrite commit text. Remove a random change. Use
        inline enables.

 drivers/bus/mhi/host/init.c | 14 ++++++++++++++
 drivers/bus/mhi/host/pm.c   | 22 ++++++++++++++++------
 2 files changed, 30 insertions(+), 6 deletions(-)

diff --git a/drivers/bus/mhi/host/init.c b/drivers/bus/mhi/host/init.c
index cbb86b2..daf315a 100644
--- a/drivers/bus/mhi/host/init.c
+++ b/drivers/bus/mhi/host/init.c
@@ -179,6 +179,11 @@ int mhi_init_irq_setup(struct mhi_controller *mhi_cntrl)
 				   "bhi", mhi_cntrl);
 	if (ret)
 		return ret;
+	/*
+	 * IRQ marked IRQF_SHARED isn't recommended to use IRQ_NOAUTOEN,
+	 * so disable it explicitly.
+	 */
+	disable_irq(mhi_cntrl->irq[0]);
 
 	for (i = 0; i < mhi_cntrl->total_ev_rings; i++, mhi_event++) {
 		if (mhi_event->offload_ev)
@@ -200,6 +205,8 @@ int mhi_init_irq_setup(struct mhi_controller *mhi_cntrl)
 				mhi_cntrl->irq[mhi_event->irq], i);
 			goto error_request;
 		}
+
+		disable_irq(mhi_cntrl->irq[mhi_event->irq]);
 	}
 
 	return 0;
@@ -1003,8 +1010,14 @@ int mhi_register_controller(struct mhi_controller *mhi_cntrl,
 
 	mhi_create_debugfs(mhi_cntrl);
 
+	ret = mhi_init_irq_setup(mhi_cntrl);
+	if (ret)
+		goto error_setup_irq;
+
 	return 0;
 
+error_setup_irq:
+	mhi_destroy_debugfs(mhi_cntrl);
 err_release_dev:
 	put_device(&mhi_dev->dev);
 err_ida_free:
@@ -1027,6 +1040,7 @@ void mhi_unregister_controller(struct mhi_controller *mhi_cntrl)
 	struct mhi_chan *mhi_chan = mhi_cntrl->mhi_chan;
 	unsigned int i;
 
+	mhi_deinit_free_irq(mhi_cntrl);
 	mhi_destroy_debugfs(mhi_cntrl);
 
 	destroy_workqueue(mhi_cntrl->hiprio_wq);
diff --git a/drivers/bus/mhi/host/pm.c b/drivers/bus/mhi/host/pm.c
index dc2e8ff..eec2d1d 100644
--- a/drivers/bus/mhi/host/pm.c
+++ b/drivers/bus/mhi/host/pm.c
@@ -500,7 +500,7 @@ static void mhi_pm_disable_transition(struct mhi_controller *mhi_cntrl)
 	for (i = 0; i < mhi_cntrl->total_ev_rings; i++, mhi_event++) {
 		if (mhi_event->offload_ev)
 			continue;
-		free_irq(mhi_cntrl->irq[mhi_event->irq], mhi_event);
+		disable_irq(mhi_cntrl->irq[mhi_event->irq]);
 		tasklet_kill(&mhi_event->task);
 	}
 
@@ -1060,12 +1060,13 @@ static void mhi_deassert_dev_wake(struct mhi_controller *mhi_cntrl,
 
 int mhi_async_power_up(struct mhi_controller *mhi_cntrl)
 {
+	struct mhi_event *mhi_event = mhi_cntrl->mhi_event;
 	enum mhi_state state;
 	enum mhi_ee_type current_ee;
 	enum dev_st_transition next_state;
 	struct device *dev = &mhi_cntrl->mhi_dev->dev;
 	u32 interval_us = 25000; /* poll register field every 25 milliseconds */
-	int ret;
+	int ret, i;
 
 	dev_info(dev, "Requested to power ON\n");
 
@@ -1117,9 +1118,18 @@ int mhi_async_power_up(struct mhi_controller *mhi_cntrl)
 		mhi_write_reg(mhi_cntrl, mhi_cntrl->bhi, BHI_INTVEC, 0);
 	}
 
-	ret = mhi_init_irq_setup(mhi_cntrl);
-	if (ret)
-		goto error_exit;
+	/*
+	 * IRQs have been reuqested during probe,
+	 * so we just need to enable them.
+	 */
+	enable_irq(mhi_cntrl->irq[0]);
+
+	for (i = 0; i < mhi_cntrl->total_ev_rings; i++, mhi_event++) {
+		if (mhi_event->offload_ev)
+			continue;
+
+		enable_irq(mhi_cntrl->irq[mhi_event->irq]);
+	}
 
 	/* Transition to next state */
 	next_state = MHI_IN_PBL(current_ee) ?
@@ -1182,7 +1192,7 @@ void mhi_power_down(struct mhi_controller *mhi_cntrl, bool graceful)
 	/* Wait for shutdown to complete */
 	flush_work(&mhi_cntrl->st_worker);
 
-	free_irq(mhi_cntrl->irq[0], mhi_cntrl);
+	disable_irq(mhi_cntrl->irq[0]);
 }
 EXPORT_SYMBOL_GPL(mhi_power_down);
 
-- 
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