Re: [PATCH] tty: serial: sc16is7xx: implemented our own oneshot-like handling

["Sean Nyekjær" <sean.nyekjaer@prevas.dk>]

On 2016-03-11 11:36, Sean Nyekjær wrote:
>
>
> On 2016-03-11 11:34, Sean Nyekjaer wrote:
Could this work as a description?

The problem here is still the use of IRQF_ONESHOT.  The semantics
of IRQF_ONESHOT are only defined w.r.t. the irq core's threaded
interrupt handling.

This implements it's own oneshot-like handling
at the device-level: in the registered irq handler, capture triggered
interrupt state, squelch/mask, and enqueue the kthread_work.  In the
tail-end of the kthread_work, re-enable interrupts at the device level.

>> Signed-off-by: Sean Nyekjaer <sean.nyekjaer@prevas.dk>
>> ---
>> This patch depends on patch "sc16is7xx: drop bogus use of IRQF_ONESHOT"
>>
>>   drivers/tty/serial/sc16is7xx.c | 9 ++++++++-
>>   1 file changed, 8 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/tty/serial/sc16is7xx.c 
>> b/drivers/tty/serial/sc16is7xx.c
>> index 73d46e2..96d1f3e 100644
>> --- a/drivers/tty/serial/sc16is7xx.c
>> +++ b/drivers/tty/serial/sc16is7xx.c
>> @@ -706,13 +706,20 @@ static void sc16is7xx_ist(struct kthread_work *ws)
>>       struct sc16is7xx_port *s = to_sc16is7xx_port(ws, irq_work);
>>       int i;
>>   -    for (i = 0; i < s->devtype->nr_uart; ++i)
>> +    for (i = 0; i < s->devtype->nr_uart; ++i) {
>>           sc16is7xx_port_irq(s, i);
>> +        enable_irq(s->p[i].port.irq);
>> +    }
>> +
> Ops one-line break to much :-(
> Waiting for other comments before fixing :-)
>
> /Sean
>>   }
>>     static irqreturn_t sc16is7xx_irq(int irq, void *dev_id)
>>   {
>>       struct sc16is7xx_port *s = (struct sc16is7xx_port *)dev_id;
>> +    int i;
>> +
>> +    for (i = 0; i < s->devtype->nr_uart; ++i)
>> +        disable_irq_nosync(s->p[i].port.irq);
>>         queue_kthread_work(&s->kworker, &s->irq_work);
>
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