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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: ca27fc26cd ("mailbox: sprd: Add Spreadtrum mailbox driver")
Signed-off-by: Orson Zhai <orson.zhai@unisoc.com>
Reviewed-by: Baolin Wang <baolin.wang7@gmail.com>
Signed-off-by: Jassi Brar <jaswinder.singh@linaro.org>
This commit is contained in:
Orson Zhai 2021-03-19 14:15:35 +08:00 committed by Jassi Brar
parent a8f9689107
commit 9468ab8403
1 changed files with 29 additions and 14 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

43
drivers/mailbox/sprd-mailbox.c
View File

@ -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];
mbox_chan_received_data(chan, (void *)msg);
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);
@ -215,18 +221,22 @@ static int sprd_mbox_startup(struct mbox_chan *chan)
struct sprd_mbox_priv *priv = to_sprd_mbox_priv(chan->mbox);
u32 val;
/* Select outbox FIFO mode and reset the outbox FIFO status */
writel(0x0, priv->outbox_base + SPRD_MBOX_FIFO_RST);
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);
/* Enable inbox FIFO overflow and delivery interrupt */
val = readl(priv->inbox_base + SPRD_MBOX_IRQ_MSK);
val &= ~(SPRD_INBOX_FIFO_OVERFLOW_IRQ | SPRD_INBOX_FIFO_DELIVER_IRQ);
writel(val, priv->inbox_base + SPRD_MBOX_IRQ_MSK);
/* Enable inbox FIFO overflow and delivery interrupt */
val = readl(priv->inbox_base + SPRD_MBOX_IRQ_MSK);
val &= ~(SPRD_INBOX_FIFO_OVERFLOW_IRQ | SPRD_INBOX_FIFO_DELIVER_IRQ);
writel(val, priv->inbox_base + SPRD_MBOX_IRQ_MSK);
/* Enable outbox FIFO not empty interrupt */
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);
/* Enable outbox FIFO not empty interrupt */
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;
}
@ -235,9 +245,13 @@ static void sprd_mbox_shutdown(struct mbox_chan *chan)
{
struct sprd_mbox_priv *priv = to_sprd_mbox_priv(chan->mbox);
/* 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_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 = {
@ -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