diff options
Diffstat (limited to 'bsps/m68k/uC5282/clock/clock.c')
| -rw-r--r-- | bsps/m68k/uC5282/clock/clock.c | 161 |
1 files changed, 161 insertions, 0 deletions
diff --git a/bsps/m68k/uC5282/clock/clock.c b/bsps/m68k/uC5282/clock/clock.c new file mode 100644 index 0000000000..8fffdc0457 --- /dev/null +++ b/bsps/m68k/uC5282/clock/clock.c @@ -0,0 +1,161 @@ +/* + * Use the last periodic interval timer (PIT3) as the system clock. + * + * Author: W. Eric Norum <norume@aps.anl.gov> + * + * COPYRIGHT (c) 2005. + * On-Line Applications Research Corporation (OAR). + * + * The license and distribution terms for this file may be + * found in the file LICENSE in this distribution or at + * http://www.rtems.org/license/LICENSE. + */ + +#include <rtems.h> +#include <rtems/timecounter.h> +#include <bsp.h> +#include <mcf5282/mcf5282.h> + +/* + * CPU load counters + * Place in static RAM so updates don't hit the SDRAM + */ +#define IDLE_COUNTER __SRAMBASE.idle_counter +#define FILTERED_IDLE __SRAMBASE.filtered_idle +#define MAX_IDLE_COUNT __SRAMBASE.max_idle_count +#define PITC_PER_TICK __SRAMBASE.pitc_per_tick +#define NSEC_PER_PITC __SRAMBASE.nsec_per_pitc +#define FILTER_SHIFT 6 + +/* + * Use INTC0 base + */ +#define CLOCK_VECTOR (64+58) + +static rtems_timecounter_simple uC5282_tc; + +static uint32_t uC5282_tc_get(rtems_timecounter_simple *tc) +{ + return MCF5282_PIT3_PCNTR; +} + +static bool uC5282_tc_is_pending(rtems_timecounter_simple *tc) +{ + return (MCF5282_PIT3_PCSR & MCF5282_PIT_PCSR_PIF) != 0; +} + +static uint32_t uC5282_tc_get_timecount(struct timecounter *tc) +{ + return rtems_timecounter_simple_downcounter_get( + tc, + uC5282_tc_get, + uC5282_tc_is_pending + ); +} + +static void uC5282_tc_at_tick(rtems_timecounter_simple *tc) +{ + unsigned idle = IDLE_COUNTER; + IDLE_COUNTER = 0; + if (idle > MAX_IDLE_COUNT) + MAX_IDLE_COUNT = idle; + FILTERED_IDLE = idle + FILTERED_IDLE - (FILTERED_IDLE>>FILTER_SHIFT); + MCF5282_PIT3_PCSR |= MCF5282_PIT_PCSR_PIF; +} + +static void uC5282_tc_tick(void) +{ + rtems_timecounter_simple_downcounter_tick( + &uC5282_tc, + uC5282_tc_get, + uC5282_tc_at_tick + ); +} + +/* + * Attach clock interrupt handler + */ +#define Clock_driver_support_install_isr( _new ) \ + set_vector(_new, CLOCK_VECTOR, 1) + +/* + * Turn off the clock + */ +#define Clock_driver_support_shutdown_hardware() \ + do { \ + MCF5282_PIT3_PCSR &= ~MCF5282_PIT_PCSR_EN; \ + } while(0) + +/* + * Set up the clock hardware + * + * f_pit = f_clk / 2^(preScaleCode+1) / N = 1/(us_per_tick/us_per_s) + * + * N = f_clk / 2^(preScaleCode+1) * us_per_tick / us_per_s + * + * ns_per_pit_clk = ns_per_s / (f_clk / 2^(preScaleCode+1)) + * = ns_per_s * 2^(preScaleCode+1) / f_clk; + */ +#define Clock_driver_support_initialize_hardware() \ + do { \ + unsigned long long N; \ + int level; \ + int preScaleCode = 0; \ + N = bsp_get_CPU_clock_speed(); \ + N *= rtems_configuration_get_microseconds_per_tick(); \ + N /= 2*1000000; /* min_prescale * us_per_s */ \ + while ( N > 0x10000 ) { \ + preScaleCode++; \ + N >>= 1; \ + } \ + PITC_PER_TICK = N; \ + N = 2000000000ULL << preScaleCode; \ + N /= bsp_get_CPU_clock_speed(); \ + NSEC_PER_PITC = N; \ + IDLE_COUNTER = 0; \ + FILTERED_IDLE = 0; \ + MAX_IDLE_COUNT = 0; \ + bsp_allocate_interrupt(PIT3_IRQ_LEVEL, PIT3_IRQ_PRIORITY); \ + MCF5282_INTC0_ICR58 = MCF5282_INTC_ICR_IL(PIT3_IRQ_LEVEL) | \ + MCF5282_INTC_ICR_IP(PIT3_IRQ_PRIORITY); \ + rtems_interrupt_disable( level ); \ + MCF5282_INTC0_IMRH &= ~MCF5282_INTC_IMRH_INT58; \ + MCF5282_PIT3_PCSR &= ~MCF5282_PIT_PCSR_EN; \ + rtems_interrupt_enable( level ); \ + MCF5282_PIT3_PCSR = MCF5282_PIT_PCSR_PRE(preScaleCode) | \ + MCF5282_PIT_PCSR_OVW | \ + MCF5282_PIT_PCSR_PIE | \ + MCF5282_PIT_PCSR_RLD; \ + MCF5282_PIT3_PMR = PITC_PER_TICK - 1; \ + MCF5282_PIT3_PCSR = MCF5282_PIT_PCSR_PRE(preScaleCode) | \ + MCF5282_PIT_PCSR_PIE | \ + MCF5282_PIT_PCSR_RLD | \ + MCF5282_PIT_PCSR_EN; \ + rtems_timecounter_simple_install( \ + &uC5282_tc, \ + bsp_get_CPU_clock_speed() >> (preScaleCode + 1), \ + PITC_PER_TICK, \ + uC5282_tc_get_timecount \ + ); \ + } while (0) + +/* + * Provide our own version of the idle task + */ +void * bsp_idle_thread(uint32_t ignored) +{ + /* Atomic increment */ + for(;;) + __asm__ volatile ("addq.l #1,%0"::"m"(IDLE_COUNTER)); +} + +int bsp_cpu_load_percentage(void) +{ + return MAX_IDLE_COUNT ? + (100 - ((100 * (FILTERED_IDLE >> FILTER_SHIFT)) / MAX_IDLE_COUNT)) : + 0; +} + +#define Clock_driver_timecounter_tick() uC5282_tc_tick() + +#include "../../../shared/dev/clock/clockimpl.h" |