On Fri, 2012-12-21 at 23:34 +0800, Woody Wu wrote: > On Thu, Dec 20, 2012 at 10:05:05AM -0800, anish singh wrote: > > On Dec 20, 2012 6:30 AM, "Woody Wu" <narkewoody@xxxxxxxxx> wrote: > > > > > > Hi, List > > > > > > Where is the Kernel code that handles external interrupts? I want to > > > have a look at it but haven't found out where it is. > > > > > > Actually, I have some basic questions about interrupt handling in Linux. > > > 1. After Kernel's ISR received an interrupt, I believe it will invoke a > > > handler defined in a device driver if any. But it should be the > > > device driver's responsibility or kernel ISR's responsibility to > > > clear (or acknowledge) the interrupt? > > If the interrupt in question is currently being handled then in > > the case of edge triggered interrupt we just mask the interrupt,set it > > pending and bail out.Once the interrupt handler completes then we check for > > pending interrupt and handle it.In level triggered we don't do that. > > Kerenel ISR -this is mixture of core kernel interrupt handling code + your > > device driver interrupt handler(if this is chip driver which is supposed to > > get one interrupt and is reponsible for calling other interrupt handlers > > based on the chip register status then you do explicit masking unmasking > > yourself). > > If you device driver is a interrupt controller driver then you register > > your driver with kernel interrupt handling code and need to write some > > callbacks such as .mask,.unmask and so on.This callbacks are called at > > appropiate places whenever the interrupt is raised.This interrupt is then > > passed to drivers who has requested for this interrupt by calling > > request_irq. > > > > > > 2. My device, an AX88796B network controller, asserting the interrupt > > > line in a level-triggered manner. Now I met problem with the device > > that > > > might caused by the CPU interrupt mode is not set as level-triggered by > > > edge trigger. My CPU is Samsung S3C2410, an ARM920T powered one. Does > > > anyone know usually where and how should I do this kind of setting? > > Just pass the parameter "level triggered" in request_irq in your device > > driver. > > Hi Sign, > > I searched the interrupt.h for the all the defined flags that I can pass > to the request_irq, but there is no a flag looks like "level triggered". > Would you tell me what you mean the parameter "level triggered"? irq_set_irq_type(info->irq, IRQ_TYPE_LEVEL_LOW) include/linux/irq.h IRQ_TYPE_LEVEL_HIGH - high level triggered IRQ_TYPE_LEVEL_LOW - low level triggered > > Thanks. > > > > > > > > > > Thanks in advance. > > > > > > -- > > > woody > > > I can't go back to yesterday - because I was a different person then. > > > > > > _______________________________________________ > > > Kernelnewbies mailing list > > > Kernelnewbies@xxxxxxxxxxxxxxxxx > > > http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies > _______________________________________________ Kernelnewbies mailing list Kernelnewbies@xxxxxxxxxxxxxxxxx http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
