From af2a580f7e09359f882014e47a91e620a325537b Mon Sep 17 00:00:00 2001 From: Peter Maydell Date: Mon, 11 Nov 2019 13:44:16 +0000 Subject: [PATCH] ptimer: Remove old ptimer_init_with_bh() API Now all the users of ptimers have converted to the transaction-based API, we can remove ptimer_init_with_bh() and all the code paths that are used only by bottom-half based ptimers, and tidy up the documentation comments to consider the transaction-based API the only possibility. The code changes result from: * s->bh no longer exists * s->callback is now always non-NULL Signed-off-by: Peter Maydell Reviewed-by: Richard Henderson Message-id: 20191025142411.17085-1-peter.maydell@linaro.org --- hw/core/ptimer.c | 91 ++++++++------------------------------------- include/hw/ptimer.h | 45 +++++++++++----------- 2 files changed, 36 insertions(+), 100 deletions(-) diff --git a/hw/core/ptimer.c b/hw/core/ptimer.c index 7239b8227c..b5a54e2536 100644 --- a/hw/core/ptimer.c +++ b/hw/core/ptimer.c @@ -29,7 +29,6 @@ struct ptimer_state int64_t last_event; int64_t next_event; uint8_t policy_mask; - QEMUBH *bh; QEMUTimer *timer; ptimer_cb callback; void *callback_opaque; @@ -46,12 +45,7 @@ struct ptimer_state /* Use a bottom-half routine to avoid reentrancy issues. */ static void ptimer_trigger(ptimer_state *s) { - if (s->bh) { - replay_bh_schedule_event(s->bh); - } - if (s->callback) { - s->callback(s->callback_opaque); - } + s->callback(s->callback_opaque); } static void ptimer_reload(ptimer_state *s, int delta_adjust) @@ -296,15 +290,10 @@ uint64_t ptimer_get_count(ptimer_state *s) void ptimer_set_count(ptimer_state *s, uint64_t count) { - assert(s->in_transaction || !s->callback); + assert(s->in_transaction); s->delta = count; if (s->enabled) { - if (!s->callback) { - s->next_event = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL); - ptimer_reload(s, 0); - } else { - s->need_reload = true; - } + s->need_reload = true; } } @@ -312,7 +301,7 @@ void ptimer_run(ptimer_state *s, int oneshot) { bool was_disabled = !s->enabled; - assert(s->in_transaction || !s->callback); + assert(s->in_transaction); if (was_disabled && s->period == 0) { if (!qtest_enabled()) { @@ -322,12 +311,7 @@ void ptimer_run(ptimer_state *s, int oneshot) } s->enabled = oneshot ? 2 : 1; if (was_disabled) { - if (!s->callback) { - s->next_event = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL); - ptimer_reload(s, 0); - } else { - s->need_reload = true; - } + s->need_reload = true; } } @@ -335,7 +319,7 @@ void ptimer_run(ptimer_state *s, int oneshot) is immediately restarted. */ void ptimer_stop(ptimer_state *s) { - assert(s->in_transaction || !s->callback); + assert(s->in_transaction); if (!s->enabled) return; @@ -343,42 +327,30 @@ void ptimer_stop(ptimer_state *s) s->delta = ptimer_get_count(s); timer_del(s->timer); s->enabled = 0; - if (s->callback) { - s->need_reload = false; - } + s->need_reload = false; } /* Set counter increment interval in nanoseconds. */ void ptimer_set_period(ptimer_state *s, int64_t period) { - assert(s->in_transaction || !s->callback); + assert(s->in_transaction); s->delta = ptimer_get_count(s); s->period = period; s->period_frac = 0; if (s->enabled) { - if (!s->callback) { - s->next_event = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL); - ptimer_reload(s, 0); - } else { - s->need_reload = true; - } + s->need_reload = true; } } /* Set counter frequency in Hz. */ void ptimer_set_freq(ptimer_state *s, uint32_t freq) { - assert(s->in_transaction || !s->callback); + assert(s->in_transaction); s->delta = ptimer_get_count(s); s->period = 1000000000ll / freq; s->period_frac = (1000000000ll << 32) / freq; if (s->enabled) { - if (!s->callback) { - s->next_event = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL); - ptimer_reload(s, 0); - } else { - s->need_reload = true; - } + s->need_reload = true; } } @@ -386,17 +358,12 @@ void ptimer_set_freq(ptimer_state *s, uint32_t freq) count = limit. */ void ptimer_set_limit(ptimer_state *s, uint64_t limit, int reload) { - assert(s->in_transaction || !s->callback); + assert(s->in_transaction); s->limit = limit; if (reload) s->delta = limit; if (s->enabled && reload) { - if (!s->callback) { - s->next_event = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL); - ptimer_reload(s, 0); - } else { - s->need_reload = true; - } + s->need_reload = true; } } @@ -407,7 +374,7 @@ uint64_t ptimer_get_limit(ptimer_state *s) void ptimer_transaction_begin(ptimer_state *s) { - assert(!s->in_transaction || !s->callback); + assert(!s->in_transaction); s->in_transaction = true; s->need_reload = false; } @@ -448,37 +415,12 @@ const VMStateDescription vmstate_ptimer = { } }; -ptimer_state *ptimer_init_with_bh(QEMUBH *bh, uint8_t policy_mask) -{ - ptimer_state *s; - - s = (ptimer_state *)g_malloc0(sizeof(ptimer_state)); - s->bh = bh; - s->timer = timer_new_ns(QEMU_CLOCK_VIRTUAL, ptimer_tick, s); - s->policy_mask = policy_mask; - - /* - * These two policies are incompatible -- trigger-on-decrement implies - * a timer trigger when the count becomes 0, but no-immediate-trigger - * implies a trigger when the count stops being 0. - */ - assert(!((policy_mask & PTIMER_POLICY_TRIGGER_ONLY_ON_DECREMENT) && - (policy_mask & PTIMER_POLICY_NO_IMMEDIATE_TRIGGER))); - return s; -} - ptimer_state *ptimer_init(ptimer_cb callback, void *callback_opaque, uint8_t policy_mask) { ptimer_state *s; - /* - * The callback function is mandatory; so we use it to distinguish - * old-style QEMUBH ptimers from new transaction API ptimers. - * (ptimer_init_with_bh() allows a NULL bh pointer and at least - * one device (digic-timer) passes NULL, so it's not the case - * that either s->bh != NULL or s->callback != NULL.) - */ + /* The callback function is mandatory. */ assert(callback); s = g_new0(ptimer_state, 1); @@ -499,9 +441,6 @@ ptimer_state *ptimer_init(ptimer_cb callback, void *callback_opaque, void ptimer_free(ptimer_state *s) { - if (s->bh) { - qemu_bh_delete(s->bh); - } timer_free(s->timer); g_free(s); } diff --git a/include/hw/ptimer.h b/include/hw/ptimer.h index 4c321f65dc..412763fffb 100644 --- a/include/hw/ptimer.h +++ b/include/hw/ptimer.h @@ -10,15 +10,24 @@ #include "qemu/timer.h" -/* The ptimer API implements a simple periodic countdown timer. +/* + * The ptimer API implements a simple periodic countdown timer. * The countdown timer has a value (which can be read and written via * ptimer_get_count() and ptimer_set_count()). When it is enabled * using ptimer_run(), the value will count downwards at the frequency * which has been configured using ptimer_set_period() or ptimer_set_freq(). - * When it reaches zero it will trigger a QEMU bottom half handler, and + * When it reaches zero it will trigger a callback function, and * can be set to either reload itself from a specified limit value * and keep counting down, or to stop (as a one-shot timer). * + * A transaction-based API is used for modifying ptimer state: all calls + * to functions which modify ptimer state must be between matched calls to + * ptimer_transaction_begin() and ptimer_transaction_commit(). + * When ptimer_transaction_commit() is called it will evaluate the state + * of the timer after all the changes in the transaction, and call the + * callback if necessary. (See the ptimer_init() documentation for the full + * list of state-modifying functions and detailed semantics of the callback.) + * * Forgetting to set the period/frequency (or setting it to zero) is a * bug in the QEMU device and will cause warning messages to be printed * to stderr when the guest attempts to enable the timer. @@ -72,7 +81,7 @@ * ptimer_set_count() or ptimer_set_limit() will not trigger the timer * (though it will cause a reload). Only a counter decrement to "0" * will cause a trigger. Not compatible with NO_IMMEDIATE_TRIGGER; - * ptimer_init_with_bh() will assert() that you don't set both. + * ptimer_init() will assert() that you don't set both. */ #define PTIMER_POLICY_TRIGGER_ONLY_ON_DECREMENT (1 << 5) @@ -80,17 +89,6 @@ typedef struct ptimer_state ptimer_state; typedef void (*ptimer_cb)(void *opaque); -/** - * ptimer_init_with_bh - Allocate and return a new ptimer - * @bh: QEMU bottom half which is run on timer expiry - * @policy: PTIMER_POLICY_* bits specifying behaviour - * - * The ptimer returned must be freed using ptimer_free(). - * The ptimer takes ownership of @bh and will delete it - * when the ptimer is eventually freed. - */ -ptimer_state *ptimer_init_with_bh(QEMUBH *bh, uint8_t policy_mask); - /** * ptimer_init - Allocate and return a new ptimer * @callback: function to call on ptimer expiry @@ -127,8 +125,7 @@ ptimer_state *ptimer_init(ptimer_cb callback, * ptimer_free - Free a ptimer * @s: timer to free * - * Free a ptimer created using ptimer_init_with_bh() (including - * deleting the bottom half which it is using). + * Free a ptimer created using ptimer_init(). */ void ptimer_free(ptimer_state *s); @@ -164,7 +161,7 @@ void ptimer_transaction_commit(ptimer_state *s); * may be more appropriate. * * This function will assert if it is called outside a - * ptimer_transaction_begin/commit block, unless this is a bottom-half ptimer. + * ptimer_transaction_begin/commit block. */ void ptimer_set_period(ptimer_state *s, int64_t period); @@ -180,7 +177,7 @@ void ptimer_set_period(ptimer_state *s, int64_t period); * precise to fractions of a nanosecond, avoiding rounding errors. * * This function will assert if it is called outside a - * ptimer_transaction_begin/commit block, unless this is a bottom-half ptimer. + * ptimer_transaction_begin/commit block. */ void ptimer_set_freq(ptimer_state *s, uint32_t freq); @@ -210,7 +207,7 @@ uint64_t ptimer_get_limit(ptimer_state *s); * reload the counter when their reload register is written to. * * This function will assert if it is called outside a - * ptimer_transaction_begin/commit block, unless this is a bottom-half ptimer. + * ptimer_transaction_begin/commit block. */ void ptimer_set_limit(ptimer_state *s, uint64_t limit, int reload); @@ -234,7 +231,7 @@ uint64_t ptimer_get_count(ptimer_state *s); * point in the future. * * This function will assert if it is called outside a - * ptimer_transaction_begin/commit block, unless this is a bottom-half ptimer. + * ptimer_transaction_begin/commit block. */ void ptimer_set_count(ptimer_state *s, uint64_t count); @@ -243,15 +240,15 @@ void ptimer_set_count(ptimer_state *s, uint64_t count); * @s: ptimer * @oneshot: non-zero if this timer should only count down once * - * Start a ptimer counting down; when it reaches zero the bottom half - * passed to ptimer_init_with_bh() will be invoked. + * Start a ptimer counting down; when it reaches zero the callback function + * passed to ptimer_init() will be invoked. * If the @oneshot argument is zero, * the counter value will then be reloaded from the limit and it will * start counting down again. If @oneshot is non-zero, then the counter * will disable itself when it reaches zero. * * This function will assert if it is called outside a - * ptimer_transaction_begin/commit block, unless this is a bottom-half ptimer. + * ptimer_transaction_begin/commit block. */ void ptimer_run(ptimer_state *s, int oneshot); @@ -266,7 +263,7 @@ void ptimer_run(ptimer_state *s, int oneshot); * restarted. * * This function will assert if it is called outside a - * ptimer_transaction_begin/commit block, unless this is a bottom-half ptimer. + * ptimer_transaction_begin/commit block. */ void ptimer_stop(ptimer_state *s);