From ef0a9984aa0c3c8f440bbf488f2c14ccddd241ea Mon Sep 17 00:00:00 2001 From: Dmitry Osipenko Date: Mon, 24 Oct 2016 16:26:51 +0100 Subject: [PATCH] hw/ptimer: Add "continuous trigger" policy Currently, periodic timer that has load = delta = 0 performs trigger on timer reload and stops, printing a "period zero" error message. Introduce new policy that makes periodic timer to continuously trigger with a period interval in case of load = 0. Signed-off-by: Dmitry Osipenko Message-id: 632b23dd11055d9bd5e338d66b38fac0bd51462e.1475421224.git.digetx@gmail.com Reviewed-by: Peter Maydell Signed-off-by: Peter Maydell --- hw/core/ptimer.c | 30 +++++++++++++++++++++++++++--- include/hw/ptimer.h | 4 ++++ 2 files changed, 31 insertions(+), 3 deletions(-) diff --git a/hw/core/ptimer.c b/hw/core/ptimer.c index 1f4122da4e..1aa019447f 100644 --- a/hw/core/ptimer.c +++ b/hw/core/ptimer.c @@ -47,7 +47,8 @@ static void ptimer_reload(ptimer_state *s, int delta_adjust) ptimer_trigger(s); delta = s->delta = s->limit; } - if (delta == 0 || s->period == 0) { + + if (s->period == 0) { if (!qtest_enabled()) { fprintf(stderr, "Timer with period zero, disabling\n"); } @@ -60,6 +61,21 @@ static void ptimer_reload(ptimer_state *s, int delta_adjust) delta += delta_adjust; } + if (delta == 0 && (s->policy_mask & PTIMER_POLICY_CONTINUOUS_TRIGGER)) { + if (s->enabled == 1 && s->limit == 0) { + delta = 1; + } + } + + if (delta == 0) { + if (!qtest_enabled()) { + fprintf(stderr, "Timer with delta zero, disabling\n"); + } + timer_del(s->timer); + s->enabled = 0; + return; + } + /* * Artificially limit timeout rate to something * achievable under QEMU. Otherwise, QEMU spends all @@ -90,7 +106,15 @@ static void ptimer_tick(void *opaque) if (s->enabled == 2) { s->enabled = 0; } else { - ptimer_reload(s, DELTA_ADJUST); + int delta_adjust = DELTA_ADJUST; + + if (s->limit == 0) { + /* If a "continuous trigger" policy is not used and limit == 0, + we should error out. */ + delta_adjust = 0; + } + + ptimer_reload(s, delta_adjust); } } @@ -98,7 +122,7 @@ uint64_t ptimer_get_count(ptimer_state *s) { uint64_t counter; - if (s->enabled) { + if (s->enabled && s->delta != 0) { int64_t now = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL); int64_t next = s->next_event; int64_t last = s->last_event; diff --git a/include/hw/ptimer.h b/include/hw/ptimer.h index 03441cbc22..b2fb4f9864 100644 --- a/include/hw/ptimer.h +++ b/include/hw/ptimer.h @@ -39,6 +39,10 @@ * around. */ #define PTIMER_POLICY_WRAP_AFTER_ONE_PERIOD (1 << 0) +/* Running periodic timer that has counter = limit = 0 would continuously + * re-trigger every period. */ +#define PTIMER_POLICY_CONTINUOUS_TRIGGER (1 << 1) + /* ptimer.c */ typedef struct ptimer_state ptimer_state; typedef void (*ptimer_cb)(void *opaque); -- 2.11.0