| /* system clock support for nanokernel-only systems */ |
| |
| /* |
| * Copyright (c) 1997-2015 Wind River Systems, Inc. |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| |
| #include <nano_private.h> |
| #include <toolchain.h> |
| #include <sections.h> |
| #include <wait_q.h> |
| #include <drivers/system_timer.h> |
| |
| #ifdef CONFIG_SYS_CLOCK_EXISTS |
| int sys_clock_us_per_tick = 1000000 / sys_clock_ticks_per_sec; |
| int sys_clock_hw_cycles_per_tick = |
| CONFIG_SYS_CLOCK_HW_CYCLES_PER_SEC / sys_clock_ticks_per_sec; |
| #if defined(CONFIG_TIMER_READS_ITS_FREQUENCY_AT_RUNTIME) |
| int sys_clock_hw_cycles_per_sec = CONFIG_SYS_CLOCK_HW_CYCLES_PER_SEC; |
| #endif |
| #else |
| /* don't initialize to avoid division-by-zero error */ |
| int sys_clock_us_per_tick; |
| int sys_clock_hw_cycles_per_tick; |
| #if defined(CONFIG_TIMER_READS_ITS_FREQUENCY_AT_RUNTIME) |
| int sys_clock_hw_cycles_per_sec; |
| #endif |
| #endif |
| |
| #ifdef CONFIG_NANOKERNEL |
| |
| /* updated by timer driver for tickless, stays at 1 for non-tickless */ |
| int32_t _sys_idle_elapsed_ticks = 1; |
| #endif /* CONFIG_NANOKERNEL */ |
| |
| int64_t _sys_clock_tick_count; |
| |
| /** |
| * |
| * @brief Return the lower part of the current system tick count |
| * |
| * @return the current system tick count |
| * |
| */ |
| uint32_t sys_tick_get_32(void) |
| { |
| return (uint32_t)_sys_clock_tick_count; |
| } |
| |
| /** |
| * |
| * @brief Return the current system tick count |
| * |
| * @return the current system tick count |
| * |
| */ |
| int64_t sys_tick_get(void) |
| { |
| int64_t tmp_sys_clock_tick_count; |
| /* |
| * Lock the interrupts when reading _sys_clock_tick_count 64-bit |
| * variable. Some architectures (x86) do not handle 64-bit atomically, |
| * so we have to lock the timer interrupt that causes change of |
| * _sys_clock_tick_count |
| */ |
| unsigned int imask = irq_lock(); |
| |
| tmp_sys_clock_tick_count = _sys_clock_tick_count; |
| irq_unlock(imask); |
| return tmp_sys_clock_tick_count; |
| } |
| |
| /** |
| * |
| * @brief Return number of ticks since a reference time |
| * |
| * This function is meant to be used in contained fragments of code. The first |
| * call to it in a particular code fragment fills in a reference time variable |
| * which then gets passed and updated every time the function is called. From |
| * the second call on, the delta between the value passed to it and the current |
| * tick count is the return value. Since the first call is meant to only fill in |
| * the reference time, its return value should be discarded. |
| * |
| * Since a code fragment that wants to use sys_tick_delta() passes in its |
| * own reference time variable, multiple code fragments can make use of this |
| * function concurrently. |
| * |
| * e.g. |
| * uint64_t reftime; |
| * (void) sys_tick_delta(&reftime); /# prime it #/ |
| * [do stuff] |
| * x = sys_tick_delta(&reftime); /# how long since priming #/ |
| * [do more stuff] |
| * y = sys_tick_delta(&reftime); /# how long since [do stuff] #/ |
| * |
| * @return tick count since reference time; undefined for first invocation |
| * |
| * NOTE: We use inline function for both 64-bit and 32-bit functions. |
| * Compiler optimizes out 64-bit result handling in 32-bit version. |
| */ |
| static ALWAYS_INLINE int64_t _nano_tick_delta(int64_t *reftime) |
| { |
| int64_t delta; |
| int64_t saved; |
| |
| /* |
| * Lock the interrupts when reading _sys_clock_tick_count 64-bit |
| * variable. Some architectures (x86) do not handle 64-bit atomically, |
| * so we have to lock the timer interrupt that causes change of |
| * _sys_clock_tick_count |
| */ |
| unsigned int imask = irq_lock(); |
| |
| saved = _sys_clock_tick_count; |
| irq_unlock(imask); |
| delta = saved - (*reftime); |
| *reftime = saved; |
| |
| return delta; |
| } |
| |
| /** |
| * |
| * @brief Return number of ticks since a reference time |
| * |
| * @return tick count since reference time; undefined for first invocation |
| */ |
| int64_t sys_tick_delta(int64_t *reftime) |
| { |
| return _nano_tick_delta(reftime); |
| } |
| |
| |
| uint32_t sys_tick_delta_32(int64_t *reftime) |
| { |
| return (uint32_t)_nano_tick_delta(reftime); |
| } |
| |
| /* handle the expired timeouts in the nano timeout queue */ |
| |
| #if defined(CONFIG_NANO_TIMEOUTS) || defined(CONFIG_NANO_TIMERS) |
| #include <wait_q.h> |
| |
| static inline void handle_expired_nano_timeouts(int32_t ticks) |
| { |
| struct _nano_timeout *head = |
| (struct _nano_timeout *)sys_dlist_peek_head(&_nanokernel.timeout_q); |
| |
| _nanokernel.task_timeout = TICKS_UNLIMITED; |
| if (head) { |
| head->delta_ticks_from_prev -= ticks; |
| _nano_timeout_handle_timeouts(); |
| } |
| } |
| #else |
| #define handle_expired_nano_timeouts(ticks) do { } while ((0)) |
| #endif |
| |
| /** |
| * |
| * @brief Announce a tick to the nanokernel |
| * |
| * This function is only to be called by the system clock timer driver when a |
| * tick is to be announced to the nanokernel. It takes care of dequeuing the |
| * timers that have expired and wake up the fibers pending on them. |
| * |
| * @return N/A |
| */ |
| void _nano_sys_clock_tick_announce(int32_t ticks) |
| { |
| unsigned int key; |
| |
| key = irq_lock(); |
| _sys_clock_tick_count += ticks; |
| handle_expired_nano_timeouts(ticks); |
| irq_unlock(key); |
| } |
| |
| /* |
| * Get closest nano timeouts/timers deadline expiry, (uint32_t)TICKS_UNLIMITED |
| * if none. |
| */ |
| uint32_t _nano_get_earliest_deadline(void) |
| { |
| return _nano_get_earliest_timeouts_deadline(); |
| } |