[foxboard] Using etrax lx100 hardware timer (timer1) possible?

[dietmar.dreyer]

Hi all,

I'm working on a project where I need to periodically poll several
input pins with at least 5 kHz frequency as I need to be able to
detect the correct sequence of binary input signals.
I tried to use the timer1 interrupt from a kernel module, after
compiling a 2.4 kernel without the
fasttimer api, but I am not able to get it right.
After configuring and starting the timer, the interrupt handler is
called once and after that the system
seems to hang (all LEDs flashing simultaneously).
I am neither sure if I am configuring the timer appropriately, nor do
I know precisely whether it is actually possible to use timer1 from a
kernel module without breaking internal kernel operation.

This is the code I am using, it's pretty much the code copied from the
fasttimer/ircontrol code,
so it may be fundamentally wrong in a kernel module:

static irqreturn_t irqTimer0_interrupt(int irq, void *dev_id, struct
pt_regs *regs)
{
     r_timer_ctrl_shadow =  *R_TIMER_CTRL;

     /* acknowledge the timer1 irq */        *R_TIMER_CTRL =
r_timer_ctrl_shadow =  r_timer_ctrl_shadow |      
IO_STATE(R_TIMER_CTRL, i1, clr);

     *R_IRQ_MASK0_CLR = IO_STATE(R_IRQ_MASK0_CLR, timer1, clr);

      *R_TIMER_CTRL = r_timer_ctrl_shadow =
         (r_timer_ctrl_shadow & ~IO_MASK(R_TIMER_CTRL, tm1)) |
         IO_STATE(R_TIMER_CTRL, tm1, stop_ld);

     return IRQ_HANDLED;
}


void init_timer()
{
 unsigned long div = 2;

 // Clear timer1 irq
 *R_IRQ_MASK0_CLR = IO_STATE(R_IRQ_MASK0_CLR, timer1, clr);

 // Set timer values
 r_timer_ctrl_shadow = *R_TIMER_CTRL;


 *R_TIMER_CTRL = r_timer_ctrl_shadow =
       (r_timer_ctrl_shadow &
        ~IO_MASK(R_TIMER_CTRL, timerdiv1) &
        ~IO_MASK(R_TIMER_CTRL, tm1) &
        ~IO_MASK(R_TIMER_CTRL, clksel1)) |
       IO_FIELD(R_TIMER_CTRL, timerdiv1, FREQ_DIVIDER) |
       IO_STATE(R_TIMER_CTRL, tm1, stop_ld) |
       IO_FIELD(R_TIMER_CTRL, clksel1, 10);

   *R_TIMER_CTRL = r_timer_ctrl_shadow =
       (r_timer_ctrl_shadow & ~IO_MASK(R_TIMER_CTRL, tm1)) |
       IO_STATE(R_TIMER_CTRL, tm1, run);

   /* enable timer1 irq */

   *R_IRQ_MASK0_SET = IO_STATE(R_IRQ_MASK0_SET, timer1, set);
}




Any help on this topic will be appreciated. Thanks a lot!

Dietmar