diff options
Diffstat (limited to '')
| -rw-r--r-- | c/src/lib/libbsp/m68k/gen68360/clock/ckinit.c | 78 |
1 files changed, 37 insertions, 41 deletions
diff --git a/c/src/lib/libbsp/m68k/gen68360/clock/ckinit.c b/c/src/lib/libbsp/m68k/gen68360/clock/ckinit.c index a2a50d5715..b7d2b296ae 100644 --- a/c/src/lib/libbsp/m68k/gen68360/clock/ckinit.c +++ b/c/src/lib/libbsp/m68k/gen68360/clock/ckinit.c @@ -101,54 +101,50 @@ Clock_isr (rtems_vector_number vector) void Clock_exit (void) { - if (BSP_Configuration.ticks_per_timeslice ) { - /* - * Turn off periodic interval timer - */ - m360.pitr &= ~0xFF; - } + /* + * Turn off periodic interval timer + */ + m360.pitr &= ~0xFF; } static void Install_clock (rtems_isr_entry clock_isr) { + int divisor; + extern int m360_clock_rate; /* This should be somewhere in a config file */ + unsigned long nsec_per_chip_tick = 1000000000 / m360_clock_rate; + unsigned long nsec_per_pit_tick = 512 * nsec_per_chip_tick; + Clock_driver_ticks = 0; - if ( BSP_Configuration.ticks_per_timeslice ) { - /* - * Choose periodic interval timer register value - * The rate at which the periodic interval timer - * can generate interrupts is almost certainly not - * the same as desired by the BSP configuration. - * Handle the difference by choosing the largest PIT - * interval which is less than or equal to the RTEMS - * interval and skipping some hardware interrupts. - * To reduce the jitter in the calls to RTEMS the - * hardware interrupt interval is never less than - * the maximum non-prescaled value from the PIT. - * - * For a 25 MHz external clock the basic clock rate is - * 40 nsec * 128 * 4 = 20.48 usec/tick - */ - int divisor; - extern int m360_clock_rate; /* This should be somewhere in a config file */ - unsigned long nsec_per_chip_tick = 1000000000 / m360_clock_rate; - unsigned long nsec_per_pit_tick = 512 * nsec_per_chip_tick; - - rtems_nsec_per_tick = BSP_Configuration.microseconds_per_tick * 1000; - divisor = rtems_nsec_per_tick / nsec_per_pit_tick; - if (divisor >= 256) { - divisor = 255; - } - else if (divisor == 0) { - divisor = 1; - } - pit_nsec_per_tick = nsec_per_pit_tick * divisor; - m360.pitr &= ~0x1FF; - m360.picr = (CLOCK_IRQ_LEVEL << 8) | CLOCK_VECTOR; - set_vector (clock_isr, CLOCK_VECTOR, 1); - m360.pitr |= divisor; - atexit (Clock_exit); + /* + * Choose periodic interval timer register value + * The rate at which the periodic interval timer + * can generate interrupts is almost certainly not + * the same as desired by the BSP configuration. + * Handle the difference by choosing the largest PIT + * interval which is less than or equal to the RTEMS + * interval and skipping some hardware interrupts. + * To reduce the jitter in the calls to RTEMS the + * hardware interrupt interval is never less than + * the maximum non-prescaled value from the PIT. + * + * For a 25 MHz external clock the basic clock rate is + * 40 nsec * 128 * 4 = 20.48 usec/tick + */ + + rtems_nsec_per_tick = BSP_Configuration.microseconds_per_tick * 1000; + divisor = rtems_nsec_per_tick / nsec_per_pit_tick; + if (divisor >= 256) { + divisor = 255; + } else if (divisor == 0) { + divisor = 1; } + pit_nsec_per_tick = nsec_per_pit_tick * divisor; + m360.pitr &= ~0x1FF; + m360.picr = (CLOCK_IRQ_LEVEL << 8) | CLOCK_VECTOR; + set_vector (clock_isr, CLOCK_VECTOR, 1); + m360.pitr |= divisor; + atexit (Clock_exit); } rtems_device_driver |