| /* |
| * Copyright (c) 2008 Travis Geiselbrecht |
| * |
| * Permission is hereby granted, free of charge, to any person obtaining |
| * a copy of this software and associated documentation files |
| * (the "Software"), to deal in the Software without restriction, |
| * including without limitation the rights to use, copy, modify, merge, |
| * publish, distribute, sublicense, and/or sell copies of the Software, |
| * and to permit persons to whom the Software is furnished to do so, |
| * subject to the following conditions: |
| * |
| * The above copyright notice and this permission notice shall be |
| * included in all copies or substantial portions of the Software. |
| * |
| * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, |
| * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF |
| * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. |
| * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY |
| * CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, |
| * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE |
| * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. |
| */ |
| #include <err.h> |
| #include <debug.h> |
| #include <sys/types.h> |
| |
| #include <kernel/thread.h> |
| #include <platform/timer.h> |
| #include <platform/interrupts.h> |
| #include <platform/debug.h> |
| #include <platform/at91sam7.h> |
| |
| #define FIXED_1KHZ_TIMER 0 |
| |
| static platform_timer_callback timer_func; |
| |
| static volatile time_t ticks = 0; |
| |
| #if FIXED_1KHZ_TIMER |
| static volatile int timer_interval; |
| static volatile int timer_downcount; |
| #else |
| static int timer_ms_per_tick; |
| #endif |
| |
| time_t current_time(void) |
| { |
| return ticks; |
| } |
| |
| bigtime_t current_time_hires(void) |
| { |
| return ticks * 1000ULL; |
| } |
| |
| static enum handler_return pit_irq_handler(void *arg) |
| { |
| AT91PIT *pit = AT91PIT_ADDR; |
| unsigned n = PIT_PICNT(pit->PIVR); |
| |
| #if FIXED_1KHZ_TIMER |
| ticks += n; |
| timer_downcount -= n; |
| |
| if(timer_downcount <= 0) { |
| timer_downcount = timer_interval; |
| return timer_func(0, ticks); |
| } else { |
| return INT_NO_RESCHEDULE; |
| } |
| #else |
| ticks += (n * timer_ms_per_tick); |
| return timer_func(0, ticks); |
| #endif |
| } |
| |
| status_t platform_set_periodic_timer(platform_timer_callback callback, |
| void *arg, time_t interval) |
| { |
| unsigned n; |
| |
| AT91PIT *pit = AT91PIT_ADDR; |
| |
| n = AT91_MCK_MHZ / 16 / 1000; |
| dprintf(INFO, "timer: MCK=%dKHz, n=%d\n", AT91_MCK_MHZ / 1000, n); |
| |
| enter_critical_section(); |
| |
| timer_func = callback; |
| |
| #if FIXED_1KHZ_TIMER |
| timer_interval = interval; |
| timer_downcount = interval; |
| #else |
| timer_ms_per_tick = interval; |
| n *= interval; |
| #endif |
| |
| pit->MR = PIT_PITEN | PIT_PITIEN | (n & 0xfffff); |
| |
| register_int_handler(PID_SYSIRQ, pit_irq_handler, 0); |
| unmask_interrupt(PID_SYSIRQ); |
| |
| exit_critical_section(); |
| |
| return NO_ERROR; |
| } |
| |