1 /* 2 * General purpose implementation of a simple periodic countdown timer. 3 * 4 * Copyright (c) 2007 CodeSourcery. 5 * 6 * This code is licensed under the GNU LGPL. 7 */ 8 #ifndef PTIMER_H 9 #define PTIMER_H 10 11 #include "qemu-common.h" 12 #include "qemu/timer.h" 13 #include "migration/vmstate.h" 14 15 /* The default ptimer policy retains backward compatibility with the legacy 16 * timers. Custom policies are adjusting the default one. Consider providing 17 * a correct policy for your timer. 18 * 19 * The rough edges of the default policy: 20 * - Starting to run with a period = 0 emits error message and stops the 21 * timer without a trigger. 22 * 23 * - Setting period to 0 of the running timer emits error message and 24 * stops the timer without a trigger. 25 * 26 * - Starting to run with counter = 0 or setting it to "0" while timer 27 * is running causes a trigger and reloads counter with a limit value. 28 * If limit = 0, ptimer emits error message and stops the timer. 29 * 30 * - Counter value of the running timer is one less than the actual value. 31 * 32 * - Changing period/frequency of the running timer loses time elapsed 33 * since the last period, effectively restarting the timer with a 34 * counter = counter value at the moment of change (.i.e. one less). 35 */ 36 #define PTIMER_POLICY_DEFAULT 0 37 38 /* Periodic timer counter stays with "0" for a one period before wrapping 39 * around. */ 40 #define PTIMER_POLICY_WRAP_AFTER_ONE_PERIOD (1 << 0) 41 42 /* Running periodic timer that has counter = limit = 0 would continuously 43 * re-trigger every period. */ 44 #define PTIMER_POLICY_CONTINUOUS_TRIGGER (1 << 1) 45 46 /* ptimer.c */ 47 typedef struct ptimer_state ptimer_state; 48 typedef void (*ptimer_cb)(void *opaque); 49 50 ptimer_state *ptimer_init(QEMUBH *bh, uint8_t policy_mask); 51 void ptimer_set_period(ptimer_state *s, int64_t period); 52 void ptimer_set_freq(ptimer_state *s, uint32_t freq); 53 uint64_t ptimer_get_limit(ptimer_state *s); 54 void ptimer_set_limit(ptimer_state *s, uint64_t limit, int reload); 55 uint64_t ptimer_get_count(ptimer_state *s); 56 void ptimer_set_count(ptimer_state *s, uint64_t count); 57 void ptimer_run(ptimer_state *s, int oneshot); 58 void ptimer_stop(ptimer_state *s); 59 60 extern const VMStateDescription vmstate_ptimer; 61 62 #define VMSTATE_PTIMER(_field, _state) \ 63 VMSTATE_STRUCT_POINTER_V(_field, _state, 1, vmstate_ptimer, ptimer_state) 64 65 #define VMSTATE_PTIMER_ARRAY(_f, _s, _n) \ 66 VMSTATE_ARRAY_OF_POINTER_TO_STRUCT(_f, _s, _n, 0, \ 67 vmstate_ptimer, ptimer_state) 68 69 #endif 70