Commit 9468ab84 authored by Orson Zhai's avatar Orson Zhai Committed by Jassi Brar
Browse files

mailbox: sprd: Introduce refcnt when clients requests/free channels 



Unisoc mailbox has no way to be enabled/disabled for any single channel.
They can only be set to startup or shutdown as a whole device at same time.

Add a variable to count references to avoid mailbox FIFO being reset
unexpectedly when clients are requesting or freeing channels.

Also add a lock to dismiss possible conflicts from register r/w in
different startup or shutdown threads. And fix the crash problem when early
interrupts come from channel which has not been requested by client yet.

Fixes: ca27fc26 ("mailbox: sprd: Add Spreadtrum mailbox driver")
Signed-off-by: default avatarOrson Zhai <orson.zhai@unisoc.com>
Reviewed-by: default avatarBaolin Wang <baolin.wang7@gmail.com>
Signed-off-by: default avatarJassi Brar <jaswinder.singh@linaro.org>
parent a8f96891

drivers/mailbox/sprd-mailbox.c

+29 −14
Original line number Diff line number Diff line
@@ -60,6 +60,8 @@ struct sprd_mbox_priv { 
	struct clk		*clk;

	u32			outbox_fifo_depth;



	struct mutex		lock;

	u32			refcnt;

	struct mbox_chan	chan[SPRD_MBOX_CHAN_MAX];

};
@@ -115,7 +117,11 @@ static irqreturn_t sprd_mbox_outbox_isr(int irq, void *data) 
		id = readl(priv->outbox_base + SPRD_MBOX_ID);



		chan = &priv->chan[id];

		if (chan->cl)

			mbox_chan_received_data(chan, (void *)msg);

		else

			dev_warn_ratelimited(priv->dev,

				    "message's been dropped at ch[%d]\n", id);



		/* Trigger to update outbox FIFO pointer */

		writel(0x1, priv->outbox_base + SPRD_MBOX_TRIGGER);
@@ -215,6 +221,8 @@ static int sprd_mbox_startup(struct mbox_chan *chan) 
	struct sprd_mbox_priv *priv = to_sprd_mbox_priv(chan->mbox);

	u32 val;



	mutex_lock(&priv->lock);

	if (priv->refcnt++ == 0) {

		/* Select outbox FIFO mode and reset the outbox FIFO status */

		writel(0x0, priv->outbox_base + SPRD_MBOX_FIFO_RST);
@@ -227,6 +235,8 @@ static int sprd_mbox_startup(struct mbox_chan *chan) 
		val = readl(priv->outbox_base + SPRD_MBOX_IRQ_MSK);

		val &= ~SPRD_OUTBOX_FIFO_NOT_EMPTY_IRQ;

		writel(val, priv->outbox_base + SPRD_MBOX_IRQ_MSK);

	}

	mutex_unlock(&priv->lock);



	return 0;

}
@@ -235,10 +245,14 @@ static void sprd_mbox_shutdown(struct mbox_chan *chan) 
{

	struct sprd_mbox_priv *priv = to_sprd_mbox_priv(chan->mbox);



	mutex_lock(&priv->lock);

	if (--priv->refcnt == 0) {

		/* Disable inbox & outbox interrupt */

		writel(SPRD_INBOX_FIFO_IRQ_MASK, priv->inbox_base + SPRD_MBOX_IRQ_MSK);

		writel(SPRD_OUTBOX_FIFO_IRQ_MASK, priv->outbox_base + SPRD_MBOX_IRQ_MSK);

	}

	mutex_unlock(&priv->lock);

}



static const struct mbox_chan_ops sprd_mbox_ops = {

	.send_data	= sprd_mbox_send_data,
@@ -266,6 +280,7 @@ static int sprd_mbox_probe(struct platform_device *pdev) 
		return -ENOMEM;



	priv->dev = dev;

	mutex_init(&priv->lock);



	/*

	 * The Spreadtrum mailbox uses an inbox to send messages to the target