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@gmail.com> 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@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies