Travis Geiselbrecht | 1d0df69 | 2008-09-01 02:26:09 -0700 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (c) 2008 Travis Geiselbrecht |
| 3 | * |
| 4 | * Permission is hereby granted, free of charge, to any person obtaining |
| 5 | * a copy of this software and associated documentation files |
| 6 | * (the "Software"), to deal in the Software without restriction, |
| 7 | * including without limitation the rights to use, copy, modify, merge, |
| 8 | * publish, distribute, sublicense, and/or sell copies of the Software, |
| 9 | * and to permit persons to whom the Software is furnished to do so, |
| 10 | * subject to the following conditions: |
| 11 | * |
| 12 | * The above copyright notice and this permission notice shall be |
| 13 | * included in all copies or substantial portions of the Software. |
| 14 | * |
| 15 | * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, |
| 16 | * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF |
| 17 | * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. |
| 18 | * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY |
| 19 | * CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, |
| 20 | * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE |
| 21 | * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. |
| 22 | */ |
| 23 | #include <err.h> |
Travis Geiselbrecht | eb94605 | 2008-09-07 22:32:49 -0700 | [diff] [blame] | 24 | #include <debug.h> |
Travis Geiselbrecht | 1d0df69 | 2008-09-01 02:26:09 -0700 | [diff] [blame] | 25 | #include <sys/types.h> |
| 26 | |
| 27 | #include <kernel/thread.h> |
| 28 | #include <platform/timer.h> |
| 29 | #include <platform/interrupts.h> |
| 30 | #include <platform/debug.h> |
| 31 | #include <platform/at91sam7.h> |
| 32 | |
| 33 | #define FIXED_1KHZ_TIMER 0 |
| 34 | |
| 35 | static platform_timer_callback timer_func; |
| 36 | |
| 37 | static volatile time_t ticks = 0; |
| 38 | |
| 39 | #if FIXED_1KHZ_TIMER |
| 40 | static volatile int timer_interval; |
| 41 | static volatile int timer_downcount; |
| 42 | #else |
| 43 | static int timer_ms_per_tick; |
| 44 | #endif |
| 45 | |
| 46 | time_t current_time(void) |
| 47 | { |
| 48 | return ticks; |
| 49 | } |
| 50 | |
| 51 | static enum handler_return pit_irq_handler(void *arg) |
| 52 | { |
| 53 | AT91PIT *pit = AT91PIT_ADDR; |
| 54 | unsigned n = PIT_PICNT(pit->PIVR); |
| 55 | |
| 56 | #if FIXED_1KHZ_TIMER |
| 57 | ticks += n; |
| 58 | timer_downcount -= n; |
| 59 | |
| 60 | if(timer_downcount <= 0) { |
| 61 | timer_downcount = timer_interval; |
| 62 | return timer_func(0, ticks); |
| 63 | } else { |
| 64 | return INT_NO_RESCHEDULE; |
| 65 | } |
| 66 | #else |
| 67 | ticks += (n * timer_ms_per_tick); |
| 68 | return timer_func(0, ticks); |
| 69 | #endif |
| 70 | } |
| 71 | |
| 72 | status_t platform_set_periodic_timer(platform_timer_callback callback, |
| 73 | void *arg, time_t interval) |
| 74 | { |
| 75 | unsigned n; |
| 76 | |
| 77 | AT91PIT *pit = AT91PIT_ADDR; |
| 78 | |
| 79 | n = AT91_MCK_MHZ / 16 / 1000; |
Travis Geiselbrecht | eb94605 | 2008-09-07 22:32:49 -0700 | [diff] [blame] | 80 | dprintf(INFO, "timer: MCK=%dKHz, n=%d\n", AT91_MCK_MHZ / 1000, n); |
Travis Geiselbrecht | 1d0df69 | 2008-09-01 02:26:09 -0700 | [diff] [blame] | 81 | |
| 82 | enter_critical_section(); |
| 83 | |
| 84 | timer_func = callback; |
| 85 | |
| 86 | #if FIXED_1KHZ_TIMER |
| 87 | timer_interval = interval; |
| 88 | timer_downcount = interval; |
| 89 | #else |
| 90 | timer_ms_per_tick = interval; |
| 91 | n *= interval; |
| 92 | #endif |
| 93 | |
| 94 | pit->MR = PIT_PITEN | PIT_PITIEN | (n & 0xfffff); |
| 95 | |
| 96 | register_int_handler(PID_SYSIRQ, pit_irq_handler, 0); |
Travis Geiselbrecht | f1cdea3 | 2008-09-13 14:13:54 -0700 | [diff] [blame] | 97 | unmask_interrupt(PID_SYSIRQ); |
Travis Geiselbrecht | 1d0df69 | 2008-09-01 02:26:09 -0700 | [diff] [blame] | 98 | |
| 99 | exit_critical_section(); |
| 100 | |
| 101 | return NO_ERROR; |
| 102 | } |
| 103 | |