Re: [PATCH 4/4] sc16is7xx: Use threaded IRQ

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On 2020-05-08 16:37, Daniel Mack wrote:
Use a threaded IRQ handler to get rid of the irq_work kthread.
This also allows for the driver to use interrupts generated by
a threaded controller.

Signed-off-by: Daniel Mack <daniel@xxxxxxxxxx>
---
 drivers/tty/serial/sc16is7xx.c | 18 +++++-------------
 1 file changed, 5 insertions(+), 13 deletions(-)

diff --git a/drivers/tty/serial/sc16is7xx.c b/drivers/tty/serial/sc16is7xx.c
index 0997a5cac02a..e3c5b9501764 100644
--- a/drivers/tty/serial/sc16is7xx.c
+++ b/drivers/tty/serial/sc16is7xx.c
@@ -328,7 +328,6 @@ struct sc16is7xx_port {
 	unsigned char			buf[SC16IS7XX_FIFO_SIZE];
 	struct kthread_worker		kworker;
 	struct task_struct		*kworker_task;
-	struct kthread_work		irq_work;
 	struct mutex			efr_lock;
 	struct sc16is7xx_one		p[0];
 };
@@ -711,9 +710,9 @@ static bool sc16is7xx_port_irq(struct
sc16is7xx_port *s, int portno)
 	return true;
 }

-static void sc16is7xx_ist(struct kthread_work *ws)
+static irqreturn_t sc16is7xx_irq(int irq, void *dev_id)
 {
-	struct sc16is7xx_port *s = to_sc16is7xx_port(ws, irq_work);
+	struct sc16is7xx_port *s = (struct sc16is7xx_port *)dev_id;

 	mutex_lock(&s->efr_lock);

@@ -728,13 +727,6 @@ static void sc16is7xx_ist(struct kthread_work *ws)
 	}

 	mutex_unlock(&s->efr_lock);
-}
-
-static irqreturn_t sc16is7xx_irq(int irq, void *dev_id)
-{
-	struct sc16is7xx_port *s = (struct sc16is7xx_port *)dev_id;
-
-	kthread_queue_work(&s->kworker, &s->irq_work);

 	return IRQ_HANDLED;
 }
@@ -1230,7 +1222,6 @@ static int sc16is7xx_probe(struct device *dev,
 	mutex_init(&s->efr_lock);

 	kthread_init_worker(&s->kworker);
-	kthread_init_work(&s->irq_work, sc16is7xx_ist);
 	s->kworker_task = kthread_run(kthread_worker_fn, &s->kworker,
 				      "sc16is7xx");
 	if (IS_ERR(s->kworker_task)) {
@@ -1317,8 +1308,9 @@ static int sc16is7xx_probe(struct device *dev,
 	}

 	/* Setup interrupt */
-	ret = devm_request_irq(dev, irq, sc16is7xx_irq,
-			       IRQF_TRIGGER_FALLING, dev_name(dev), s);
+	ret = devm_request_threaded_irq(dev, irq, NULL, sc16is7xx_irq,
+					IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
+					dev_name(dev), s);
 	if (!ret)
 		return 0;

Since UART0 is first handled completely in the for loop before UART1 is
handled, a new interrupt may arise on UART0 while UART1 is being handled. The result is a missed interrupt since the IRQ line might not *FALL* again.

Therefor I suggest to change IRQF_TRIGGER_FALLING to IRQF_TRIGGER_LOW. This
way the thread will be retriggered after IRQ_HANDLED is returned.

Maarten




[Index of Archives]     [Kernel Newbies]     [Security]     [Netfilter]     [Bugtraq]     [Linux PPP]     [Linux FS]     [Yosemite News]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux RAID]     [Samba]     [Video 4 Linux]     [Linmodem]     [Device Mapper]     [Linux Kernel for ARM]

  Powered by Linux