在 2012-12-21 PM6:53，"anish kumar" <[email protected]>写道： > > On Fri, 2012-12-21 at 17:34 +0800, Woody Wu wrote: > > > > 在 2012-12-21 AM2:05，"anish singh" <[email protected]>写 > > 道： > > > > > > > > > On Dec 20, 2012 6:30 AM, "Woody Wu" <[email protected]> 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. > > > > Sorry not fully understand . My device is an interrupt line is back to > > inactive.Ethernet controller. It needs to response TX and RX > > interrupts triggered by the device itself. In this case , my driver is > > a chip driver or interrupt controller driver in your terms? > Your device is neither of these. > > > > If my driver needs to do the mask and unmask job, what's the kernel > > API I should call? > You don't need to worry about mask and unmask job AFAIK. > > > > And , I don't understand why there exists differences between level > > and edge triggered interrupts in terms of kernel handling. > Level type interrupts are active as long as the hardware line has the > active level. This may require to mask the interrupt and unmask it after > the associated handler has acknowledged the device, so the interrupt > line is back to inactive.
This is a little confusing. You just said I don't need to worry mask and unmask things. But now you say I need to for the level triggered interrupts... And, what's the mask and unmask APIs that I can call? > Edge interrupt occurs on the falling and/or rising edge of a hardware > signal.The occurrence is latched into the irq controller hardware > and must be acked in order to be re-enabled. > Read the code /kerel/irq/chip.c(handle_edge_irq & handle_level_irq) Thanks for pointing me there. > > > > I know my questions might be basic , so would please tell me what's > If it was not basic then this question wouldn't be in kernelnewbies > right :)? > > the kernel code for ARM architecture doing these complex jobs as you > > explained? > You don't need to worry about it but if you want to know further then I > suggest tracing the call flow from asm interrupt handler(I believe > do_irq but not sure) in arm to handle_edge_irq call flow by adding some > logs or just browsing the code. Okay I will be reading the code. If you have time please also be kind to help answer my previous questions in this message. Thanks a lot! > > > > Thanks in advance ! > > > > > > > > > > > > > 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. > > > > > > > > > > > > > > > Thanks in advance. > > > > > > > > -- > > > > woody > > > > I can't go back to yesterday - because I was a different person > > then. > > > > > > > > _______________________________________________ > > > > Kernelnewbies mailing list > > > > [email protected] > > > > http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies > > > > > >
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