Re: [Gumstix-users] help : nssp interrupt crashing the gumstix

[Dave H. <dhy...@gm...>]

Hi ashutosh,

>   I am trying to build kernel module to handle the interrupt generated
> by nssp in the gumstix
> The process followed is as follows
> firstly created a kernel module registered it as the charter device(
> which can be seen by lsmod)
> registered a interrupt(number 9 i.e. the NSSP_IRQ value) handler which
> is viewable by 'cat /proc/interrupts'
> currently there in no hardware connected to nssp pins but using it in
> the loopback mode
> and trying to get interrupt by
> -->interrupt test register
> -->timeout register
> -->receive/transmit  fifo service request
> but in all cases the system hang and is required to be restarted by
> switching off and then on the power supply
> also, i am using preloaded kernel

It would be useful to see the entire c file (and any associated header
files) as well as the console output. I'll throw out some comments
based on what you did include:

1 - Your prototype for the interrupt routine is slightly wrong. I'm
suprised you didn't get a warning on the call to request_irq. The
correct prototype is:

irqreturn_t nssp_interrupt( int irq, void *_dev, struct pt_regs *r)

and you NEED to return something (like IRQ_HANDLED). Since your
routine is declared void, you'll get some random return value.

2 - I don't see where sem is initialized. Calling down on an
unintialized semaphore wouldn't be good.

3 - Your "delay" in the nssp_init routine using:
      for(i=3D0;i<1000;i++);
will almost certainly be optimized away. You'd be better off you use
ndelay or mdelay functions.

4 - Because I can't what regs is initialized to, I'm not sure if it's
memory or pointing to the registers. If it's memory, then I don't see
where you're enabling the interrupts. If it points to the hardware,
then you're enabling the interrupts before you register an interrupt
handler.

5 - When you built your module, are you sure that the kernel that's
runnng on the gumstix matches the kernel in your buildroot? I always
like to download my built root_fs_arm so that I can be sure everything
matches.

--
Dave Hylands
Vancouver, BC, Canada
http://www.DaveHylands.com/