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Diff: targets/TARGET_NUVOTON/TARGET_M451/lp_ticker.c
- Revision:
- 153:9398a535854b
- Parent:
- 152:9a67f0b066fc
--- a/targets/TARGET_NUVOTON/TARGET_M451/lp_ticker.c Thu Dec 15 11:48:27 2016 +0000 +++ /dev/null Thu Jan 01 00:00:00 1970 +0000 @@ -1,226 +0,0 @@ -/* mbed Microcontroller Library - * Copyright (c) 2015-2016 Nuvoton - * - * 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 "lp_ticker_api.h" - -#if DEVICE_LOWPOWERTIMER - -#include "sleep_api.h" -#include "nu_modutil.h" -#include "nu_miscutil.h" -#include "critical.h" - -// lp_ticker tick = us = timestamp -#define US_PER_TICK (1) -#define US_PER_SEC (1000 * 1000) - -#define US_PER_TMR2_INT (US_PER_SEC * 10) -#define TMR2_CLK_PER_SEC (__LXT) -#define TMR2_CLK_PER_TMR2_INT ((uint32_t) ((uint64_t) US_PER_TMR2_INT * TMR2_CLK_PER_SEC / US_PER_SEC)) -#define TMR3_CLK_PER_SEC (__LXT) - -static void tmr2_vec(void); -static void tmr3_vec(void); -static void lp_ticker_arm_cd(void); - -static int lp_ticker_inited = 0; -static volatile uint32_t counter_major = 0; -static volatile uint32_t cd_major_minor_clks = 0; -static volatile uint32_t cd_minor_clks = 0; -static volatile uint32_t wakeup_tick = (uint32_t) -1; - -// NOTE: To wake the system from power down mode, timer clock source must be ether LXT or LIRC. -// NOTE: TIMER_2 for normal counting and TIMER_3 for scheduled wakeup -static const struct nu_modinit_s timer2_modinit = {TIMER_2, TMR2_MODULE, CLK_CLKSEL1_TMR2SEL_LXT, 0, TMR2_RST, TMR2_IRQn, (void *) tmr2_vec}; -static const struct nu_modinit_s timer3_modinit = {TIMER_3, TMR3_MODULE, CLK_CLKSEL1_TMR3SEL_LXT, 0, TMR3_RST, TMR3_IRQn, (void *) tmr3_vec}; - -#define TMR_CMP_MIN 2 -#define TMR_CMP_MAX 0xFFFFFFu - -void lp_ticker_init(void) -{ - if (lp_ticker_inited) { - return; - } - lp_ticker_inited = 1; - - counter_major = 0; - cd_major_minor_clks = 0; - cd_minor_clks = 0; - wakeup_tick = (uint32_t) -1; - - // Reset module - SYS_ResetModule(timer2_modinit.rsetidx); - SYS_ResetModule(timer3_modinit.rsetidx); - - // Select IP clock source - CLK_SetModuleClock(timer2_modinit.clkidx, timer2_modinit.clksrc, timer2_modinit.clkdiv); - CLK_SetModuleClock(timer3_modinit.clkidx, timer3_modinit.clksrc, timer3_modinit.clkdiv); - // Enable IP clock - CLK_EnableModuleClock(timer2_modinit.clkidx); - CLK_EnableModuleClock(timer3_modinit.clkidx); - - // Configure clock - uint32_t clk_timer2 = TIMER_GetModuleClock((TIMER_T *) NU_MODBASE(timer2_modinit.modname)); - uint32_t prescale_timer2 = clk_timer2 / TMR2_CLK_PER_SEC - 1; - MBED_ASSERT((prescale_timer2 != (uint32_t) -1) && prescale_timer2 <= 127); - MBED_ASSERT((clk_timer2 % TMR2_CLK_PER_SEC) == 0); - uint32_t cmp_timer2 = TMR2_CLK_PER_TMR2_INT; - MBED_ASSERT(cmp_timer2 >= TMR_CMP_MIN && cmp_timer2 <= TMR_CMP_MAX); - // Continuous mode - // NOTE: TIMER_CTL_CNTDATEN_Msk exists in NUC472, but not in M451. In M451, TIMER_CNT is updated continuously by default. - ((TIMER_T *) NU_MODBASE(timer2_modinit.modname))->CTL = TIMER_PERIODIC_MODE | prescale_timer2/* | TIMER_CTL_CNTDATEN_Msk*/; - ((TIMER_T *) NU_MODBASE(timer2_modinit.modname))->CMP = cmp_timer2; - - // Set vector - NVIC_SetVector(timer2_modinit.irq_n, (uint32_t) timer2_modinit.var); - NVIC_SetVector(timer3_modinit.irq_n, (uint32_t) timer3_modinit.var); - - NVIC_EnableIRQ(timer2_modinit.irq_n); - NVIC_EnableIRQ(timer3_modinit.irq_n); - - TIMER_EnableInt((TIMER_T *) NU_MODBASE(timer2_modinit.modname)); - TIMER_EnableWakeup((TIMER_T *) NU_MODBASE(timer2_modinit.modname)); - - // Schedule wakeup to match semantics of lp_ticker_get_compare_match() - lp_ticker_set_interrupt(wakeup_tick); - - // Start timer - TIMER_Start((TIMER_T *) NU_MODBASE(timer2_modinit.modname)); -} - -timestamp_t lp_ticker_read() -{ - if (! lp_ticker_inited) { - lp_ticker_init(); - } - - TIMER_T * timer2_base = (TIMER_T *) NU_MODBASE(timer2_modinit.modname); - - do { - uint64_t major_minor_clks; - uint32_t minor_clks; - - // NOTE: As TIMER_CNT = TIMER_CMP and counter_major has increased by one, TIMER_CNT doesn't change to 0 for one tick time. - // NOTE: As TIMER_CNT = TIMER_CMP or TIMER_CNT = 0, counter_major (ISR) may not sync with TIMER_CNT. So skip and fetch stable one at the cost of 1 clock delay on this read. - do { - core_util_critical_section_enter(); - - // NOTE: Order of reading minor_us/carry here is significant. - minor_clks = TIMER_GetCounter(timer2_base); - uint32_t carry = (timer2_base->INTSTS & TIMER_INTSTS_TIF_Msk) ? 1 : 0; - // When TIMER_CNT approaches TIMER_CMP and will wrap soon, we may get carry but TIMER_CNT not wrapped. Hanlde carefully carry == 1 && TIMER_CNT is near TIMER_CMP. - if (carry && minor_clks > (TMR2_CLK_PER_TMR2_INT / 2)) { - major_minor_clks = (counter_major + 1) * TMR2_CLK_PER_TMR2_INT; - } - else { - major_minor_clks = (counter_major + carry) * TMR2_CLK_PER_TMR2_INT + minor_clks; - } - - core_util_critical_section_exit(); - } - while (minor_clks == 0 || minor_clks == TMR2_CLK_PER_TMR2_INT); - - // Add power-down compensation - return ((uint64_t) major_minor_clks * US_PER_SEC / TMR3_CLK_PER_SEC / US_PER_TICK); - } - while (0); -} - -void lp_ticker_set_interrupt(timestamp_t timestamp) -{ - uint32_t now = lp_ticker_read(); - wakeup_tick = timestamp; - - TIMER_Stop((TIMER_T *) NU_MODBASE(timer3_modinit.modname)); - - /** - * FIXME: Scheduled alarm may go off incorrectly due to wrap around. - * Conditions in which delta is negative: - * 1. Wrap around - * 2. Newly scheduled alarm is behind now - */ - //int delta = (timestamp > now) ? (timestamp - now) : (uint32_t) ((uint64_t) timestamp + 0xFFFFFFFFu - now); - int delta = (int) (timestamp - now); - if (delta > 0) { - cd_major_minor_clks = (uint64_t) delta * US_PER_TICK * TMR3_CLK_PER_SEC / US_PER_SEC; - lp_ticker_arm_cd(); - } - else { - cd_major_minor_clks = cd_minor_clks = 0; - /** - * This event was in the past. Set the interrupt as pending, but don't process it here. - * This prevents a recurive loop under heavy load which can lead to a stack overflow. - */ - NVIC_SetPendingIRQ(timer3_modinit.irq_n); - } -} - -void lp_ticker_disable_interrupt(void) -{ - TIMER_DisableInt((TIMER_T *) NU_MODBASE(timer3_modinit.modname)); -} - -void lp_ticker_clear_interrupt(void) -{ - TIMER_ClearIntFlag((TIMER_T *) NU_MODBASE(timer3_modinit.modname)); -} - -static void tmr2_vec(void) -{ - TIMER_ClearIntFlag((TIMER_T *) NU_MODBASE(timer2_modinit.modname)); - TIMER_ClearWakeupFlag((TIMER_T *) NU_MODBASE(timer2_modinit.modname)); - counter_major ++; -} - -static void tmr3_vec(void) -{ - TIMER_ClearIntFlag((TIMER_T *) NU_MODBASE(timer3_modinit.modname)); - TIMER_ClearWakeupFlag((TIMER_T *) NU_MODBASE(timer3_modinit.modname)); - cd_major_minor_clks = (cd_major_minor_clks > cd_minor_clks) ? (cd_major_minor_clks - cd_minor_clks) : 0; - if (cd_major_minor_clks == 0) { - // NOTE: lp_ticker_set_interrupt() may get called in lp_ticker_irq_handler(); - lp_ticker_irq_handler(); - } - else { - lp_ticker_arm_cd(); - } -} - -static void lp_ticker_arm_cd(void) -{ - TIMER_T * timer3_base = (TIMER_T *) NU_MODBASE(timer3_modinit.modname); - - // Reset 8-bit PSC counter, 24-bit up counter value and CNTEN bit - timer3_base->CTL |= TIMER_CTL_RSTCNT_Msk; - // One-shot mode, Clock = 1 KHz - uint32_t clk_timer3 = TIMER_GetModuleClock((TIMER_T *) NU_MODBASE(timer3_modinit.modname)); - uint32_t prescale_timer3 = clk_timer3 / TMR3_CLK_PER_SEC - 1; - MBED_ASSERT((prescale_timer3 != (uint32_t) -1) && prescale_timer3 <= 127); - MBED_ASSERT((clk_timer3 % TMR3_CLK_PER_SEC) == 0); - // NOTE: TIMER_CTL_CNTDATEN_Msk exists in NUC472, but not in M451. In M451, TIMER_CNT is updated continuously by default. - timer3_base->CTL &= ~(TIMER_CTL_OPMODE_Msk | TIMER_CTL_PSC_Msk/* | TIMER_CTL_CNTDATEN_Msk*/); - timer3_base->CTL |= TIMER_ONESHOT_MODE | prescale_timer3/* | TIMER_CTL_CNTDATEN_Msk*/; - - cd_minor_clks = cd_major_minor_clks; - cd_minor_clks = NU_CLAMP(cd_minor_clks, TMR_CMP_MIN, TMR_CMP_MAX); - timer3_base->CMP = cd_minor_clks; - - TIMER_EnableInt(timer3_base); - TIMER_EnableWakeup((TIMER_T *) NU_MODBASE(timer3_modinit.modname)); - TIMER_Start(timer3_base); -} -#endif