[PATCH 4/6] mailbox: arm_mhu: migrate to threaded irq handler

[Sudeep Holla <sudeep.holla@arm.com>]

In preparation to introduce support for doorbells which require the
interrupt handlers to be threaded, this patch moves the existing
interrupt handler to threaded handler.

Also it moves out the registering and freeing of the handlers from
the mailbox startup and shutdown methods. This also is required to
support doorbells.

Cc: Jassi Brar <jaswinder.singh@linaro.org>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
---
 drivers/mailbox/arm_mhu.c | 46 +++++++++++++++++++--------------------
 1 file changed, 22 insertions(+), 24 deletions(-)

diff --git a/drivers/mailbox/arm_mhu.c b/drivers/mailbox/arm_mhu.c
index 747cab1090ff..98838d5ae108 100644
--- a/drivers/mailbox/arm_mhu.c
+++ b/drivers/mailbox/arm_mhu.c
@@ -84,33 +84,16 @@ static int mhu_startup(struct mbox_chan *chan)
 {
 	struct mhu_link *mlink = chan->con_priv;
 	u32 val;
-	int ret;
 
 	val = readl_relaxed(mlink->tx_reg + INTR_STAT_OFS);
 	writel_relaxed(val, mlink->tx_reg + INTR_CLR_OFS);
 
-	ret = request_irq(mlink->irq, mhu_rx_interrupt,
-			  IRQF_SHARED, "mhu_link", chan);
-	if (ret) {
-		dev_err(chan->mbox->dev,
-			"Unable to acquire IRQ %d\n", mlink->irq);
-		return ret;
-	}
-
 	return 0;
 }
 
-static void mhu_shutdown(struct mbox_chan *chan)
-{
-	struct mhu_link *mlink = chan->con_priv;
-
-	free_irq(mlink->irq, chan);
-}
-
 static const struct mbox_chan_ops mhu_ops = {
 	.send_data = mhu_send_data,
 	.startup = mhu_startup,
-	.shutdown = mhu_shutdown,
 	.last_tx_done = mhu_last_tx_done,
 };
 
@@ -132,13 +115,6 @@ static int mhu_probe(struct amba_device *adev, const struct amba_id *id)
 		return PTR_ERR(mhu->base);
 	}
 
-	for (i = 0; i < MHU_CHANS; i++) {
-		mhu->chan[i].con_priv = &mhu->mlink[i];
-		mhu->mlink[i].irq = adev->irq[i];
-		mhu->mlink[i].rx_reg = mhu->base + mhu_reg[i];
-		mhu->mlink[i].tx_reg = mhu->mlink[i].rx_reg + TX_REG_OFFSET;
-	}
-
 	mhu->mbox.dev = dev;
 	mhu->mbox.chans = &mhu->chan[0];
 	mhu->mbox.num_chans = MHU_CHANS;
@@ -155,6 +131,28 @@ static int mhu_probe(struct amba_device *adev, const struct amba_id *id)
 		return err;
 	}
 
+	for (i = 0; i < MHU_CHANS; i++) {
+		int irq = mhu->mlink[i].irq = adev->irq[i];
+
+		if (irq <= 0) {
+			dev_dbg(dev, "No IRQ found for Channel %d\n", i);
+			continue;
+		}
+
+		mhu->chan[i].con_priv = &mhu->mlink[i];
+		mhu->mlink[i].rx_reg = mhu->base + mhu_reg[i];
+		mhu->mlink[i].tx_reg = mhu->mlink[i].rx_reg + TX_REG_OFFSET;
+
+		err = devm_request_threaded_irq(dev, irq, NULL,
+						mhu_rx_interrupt, IRQF_ONESHOT,
+						"mhu_link", &mhu->chan[i]);
+		if (err) {
+			dev_err(dev, "Can't claim IRQ %d\n", irq);
+			mbox_controller_unregister(&mhu->mbox);
+			return err;
+		}
+	}
+
 	dev_info(dev, "ARM MHU Mailbox registered\n");
 	return 0;
 }
-- 
2.17.1