zephyr/drivers/timer/stm32_lptim_timer.c

629 lines
18 KiB
C

/*
* Copyright (c) 2018 Foundries.io Ltd
* Copyright (c) 2019 STMicroelectronics
*
* SPDX-License-Identifier: Apache-2.0
*/
#include <zephyr/init.h>
#include <soc.h>
#include <stm32_ll_lptim.h>
#include <stm32_ll_bus.h>
#include <stm32_ll_rcc.h>
#include <stm32_ll_pwr.h>
#include <stm32_ll_system.h>
#include <zephyr/drivers/clock_control.h>
#include <zephyr/drivers/clock_control/stm32_clock_control.h>
#include <zephyr/drivers/timer/system_timer.h>
#include <zephyr/sys_clock.h>
#include <zephyr/irq.h>
#include <zephyr/drivers/counter.h>
#include <zephyr/pm/policy.h>
#include <zephyr/spinlock.h>
#define DT_DRV_COMPAT st_stm32_lptim
#if DT_NUM_INST_STATUS_OKAY(DT_DRV_COMPAT) > 1
#error Only one LPTIM instance should be enabled
#endif
#define LPTIM (LPTIM_TypeDef *) DT_INST_REG_ADDR(0)
#if DT_INST_NUM_CLOCKS(0) == 1
#warning Kconfig for LPTIM source clock (LSI/LSE) is deprecated, use device tree.
static const struct stm32_pclken lptim_clk[] = {
STM32_CLOCK_INFO(0, DT_DRV_INST(0)),
/* Use Kconfig to configure source clocks fields */
/* Fortunately, values are consistent across enabled series */
#ifdef CONFIG_STM32_LPTIM_CLOCK_LSI
{.bus = STM32_SRC_LSI, .enr = LPTIM1_SEL(1)}
#else
{.bus = STM32_SRC_LSE, .enr = LPTIM1_SEL(3)}
#endif
};
#else
static const struct stm32_pclken lptim_clk[] = STM32_DT_INST_CLOCKS(0);
#endif
static const struct device *const clk_ctrl = DEVICE_DT_GET(STM32_CLOCK_CONTROL_NODE);
/*
* Assumptions and limitations:
*
* - system clock based on an LPTIM instance, clocked by LSI or LSE
* - prescaler is set to a 2^value from 1 (division of the LPTIM source clock by 1)
* to 128 (division of the LPTIM source clock by 128)
* - using LPTIM AutoReload capability to trig the IRQ (timeout irq)
* - when timeout irq occurs the counter is already reset
* - the maximum timeout duration is reached with the lptim_time_base value
* - with prescaler of 1, the max timeout (LPTIM_TIMEBASE) is 2 seconds:
* 0xFFFF / (LSE freq (32768Hz) / 1)
* - with prescaler of 128, the max timeout (LPTIM_TIMEBASE) is 256 seconds:
* 0xFFFF / (LSE freq (32768Hz) / 128)
*/
static int32_t lptim_time_base;
static uint32_t lptim_clock_freq = CONFIG_STM32_LPTIM_CLOCK;
/* The prescaler given by the DTS and to apply to the lptim_clock_freq */
static uint32_t lptim_clock_presc = DT_PROP(DT_DRV_INST(0), st_prescaler);
/* Minimum nb of clock cycles to have to set autoreload register correctly */
#define LPTIM_GUARD_VALUE 2
/* A 32bit value cannot exceed 0xFFFFFFFF/LPTIM_TIMEBASE counting cycles.
* This is for example about of 65000 x 2000ms when clocked by LSI
*/
static uint32_t accumulated_lptim_cnt;
/* Next autoreload value to set */
static uint32_t autoreload_next;
/* Indicate if the autoreload register is ready for a write */
static bool autoreload_ready = true;
static struct k_spinlock lock;
#ifdef CONFIG_STM32_LPTIM_STDBY_TIMER
#define CURRENT_CPU \
(COND_CODE_1(CONFIG_SMP, (arch_curr_cpu()->id), (_current_cpu->id)))
#define cycle_t uint32_t
/* This local variable indicates that the timeout was set right before
* entering standby state.
*
* It is used for chips that has to use a separate standby timer in such
* case because the LPTIM is not clocked in some low power mode state.
*/
static bool timeout_stdby;
/* Cycle counter before entering the standby state. */
static cycle_t lptim_cnt_pre_stdby;
/* Standby timer value before entering the standby state. */
static uint32_t stdby_timer_pre_stdby;
/* Standby timer used for timer while entering the standby state */
static const struct device *stdby_timer = DEVICE_DT_GET(DT_CHOSEN(st_lptim_stdby_timer));
#endif /* CONFIG_STM32_LPTIM_STDBY_TIMER */
static inline bool arrm_state_get(void)
{
return (LL_LPTIM_IsActiveFlag_ARRM(LPTIM) && LL_LPTIM_IsEnabledIT_ARRM(LPTIM));
}
static void lptim_irq_handler(const struct device *unused)
{
ARG_UNUSED(unused);
uint32_t autoreload = LL_LPTIM_GetAutoReload(LPTIM);
if ((LL_LPTIM_IsActiveFlag_ARROK(LPTIM) != 0)
&& LL_LPTIM_IsEnabledIT_ARROK(LPTIM) != 0) {
LL_LPTIM_ClearFlag_ARROK(LPTIM);
if ((autoreload_next > 0) && (autoreload_next != autoreload)) {
/* the new autoreload value change, we set it */
autoreload_ready = false;
LL_LPTIM_SetAutoReload(LPTIM, autoreload_next);
} else {
autoreload_ready = true;
}
}
if (arrm_state_get()) {
k_spinlock_key_t key = k_spin_lock(&lock);
/* do not change ARR yet, sys_clock_announce will do */
LL_LPTIM_ClearFLAG_ARRM(LPTIM);
/* increase the total nb of autoreload count
* used in the sys_clock_cycle_get_32() function.
*/
autoreload++;
accumulated_lptim_cnt += autoreload;
k_spin_unlock(&lock, key);
/* announce the elapsed time in ms (count register is 16bit) */
uint32_t dticks = (autoreload
* CONFIG_SYS_CLOCK_TICKS_PER_SEC)
/ lptim_clock_freq;
sys_clock_announce(IS_ENABLED(CONFIG_TICKLESS_KERNEL)
? dticks : (dticks > 0));
}
}
static void lptim_set_autoreload(uint32_t arr)
{
/* Update autoreload register */
autoreload_next = arr;
if (!autoreload_ready) {
return;
}
/* The ARR register ready, we could set it directly */
if ((arr > 0) && (arr != LL_LPTIM_GetAutoReload(LPTIM))) {
/* The new autoreload value change, we set it */
autoreload_ready = false;
LL_LPTIM_ClearFlag_ARROK(LPTIM);
LL_LPTIM_SetAutoReload(LPTIM, arr);
}
}
static inline uint32_t z_clock_lptim_getcounter(void)
{
uint32_t lp_time;
uint32_t lp_time_prev_read;
/* It should be noted that to read reliably the content
* of the LPTIM_CNT register, two successive read accesses
* must be performed and compared
*/
lp_time = LL_LPTIM_GetCounter(LPTIM);
do {
lp_time_prev_read = lp_time;
lp_time = LL_LPTIM_GetCounter(LPTIM);
} while (lp_time != lp_time_prev_read);
return lp_time;
}
void sys_clock_set_timeout(int32_t ticks, bool idle)
{
/* new LPTIM AutoReload value to set (aligned on Kernel ticks) */
uint32_t next_arr = 0;
int err;
ARG_UNUSED(idle);
#ifdef CONFIG_STM32_LPTIM_STDBY_TIMER
const struct pm_state_info *next;
next = pm_policy_next_state(CURRENT_CPU, ticks);
/* Check if STANBY or STOP3 is requested */
timeout_stdby = false;
if ((next != NULL) && idle) {
#ifdef CONFIG_PM_S2RAM
if (next->state == PM_STATE_SUSPEND_TO_RAM) {
timeout_stdby = true;
}
#endif
#ifdef CONFIG_STM32_STOP3_LP_MODE
if ((next->state == PM_STATE_SUSPEND_TO_IDLE) && (next->substate_id == 4)) {
timeout_stdby = true;
}
#endif
}
if (timeout_stdby) {
uint64_t timeout_us =
((uint64_t)ticks * USEC_PER_SEC) / CONFIG_SYS_CLOCK_TICKS_PER_SEC;
struct counter_alarm_cfg cfg = {
.callback = NULL,
.ticks = counter_us_to_ticks(stdby_timer, timeout_us),
.user_data = NULL,
.flags = 0,
};
/* Set the alarm using timer that runs the standby.
* Needed rump-up/setting time, lower accurency etc. should be
* included in the exit-latency in the power state definition.
*/
counter_cancel_channel_alarm(stdby_timer, 0);
counter_set_channel_alarm(stdby_timer, 0, &cfg);
/* Store current values to calculate a difference in
* measurements after exiting the standby state.
*/
counter_get_value(stdby_timer, &stdby_timer_pre_stdby);
lptim_cnt_pre_stdby = z_clock_lptim_getcounter();
/* Stop clocks for LPTIM, since RTC is used instead */
clock_control_off(clk_ctrl, (clock_control_subsys_t) &lptim_clk[0]);
return;
}
#endif /* CONFIG_STM32_LPTIM_STDBY_TIMER */
if (!IS_ENABLED(CONFIG_TICKLESS_KERNEL)) {
return;
}
/*
* When CONFIG_SYSTEM_CLOCK_SLOPPY_IDLE = y, ticks equals to -1
* is treated as a lptim off ; never waking up ; lptim not clocked anymore
*/
if (ticks == K_TICKS_FOREVER) {
clock_control_off(clk_ctrl, (clock_control_subsys_t) &lptim_clk[0]);
return;
}
/*
* When CONFIG_SYSTEM_CLOCK_SLOPPY_IDLE = n, ticks equals to INT_MAX
* is treated as a maximum possible value LPTIM_MAX_TIMEBASE (16bit counter)
*/
/* if LPTIM clock was previously stopped, it must now be restored */
err = clock_control_on(clk_ctrl, (clock_control_subsys_t) &lptim_clk[0]);
if (err < 0) {
return;
}
/* passing ticks==1 means "announce the next tick",
* ticks value of zero (or even negative) is legal and
* treated identically: it simply indicates the kernel would like the
* next tick announcement as soon as possible.
*/
ticks = CLAMP(ticks - 1, 1, lptim_time_base);
k_spinlock_key_t key = k_spin_lock(&lock);
/* read current counter value (cannot exceed 16bit) */
uint32_t lp_time = z_clock_lptim_getcounter();
uint32_t autoreload = LL_LPTIM_GetAutoReload(LPTIM);
if (LL_LPTIM_IsActiveFlag_ARRM(LPTIM)
|| ((autoreload - lp_time) < LPTIM_GUARD_VALUE)) {
/* interrupt happens or happens soon.
* It's impossible to set autoreload value.
*/
k_spin_unlock(&lock, key);
return;
}
/* calculate the next arr value (cannot exceed 16bit)
* adjust the next ARR match value to align on Ticks
* from the current counter value to first next Tick
*/
next_arr = (((lp_time * CONFIG_SYS_CLOCK_TICKS_PER_SEC)
/ lptim_clock_freq) + 1) * lptim_clock_freq
/ (CONFIG_SYS_CLOCK_TICKS_PER_SEC);
next_arr = next_arr + ((uint32_t)(ticks) * lptim_clock_freq)
/ CONFIG_SYS_CLOCK_TICKS_PER_SEC;
/* if the lptim_clock_freq < one ticks/sec, then next_arr must be > 0 */
/* maximise to TIMEBASE */
if (next_arr > lptim_time_base) {
next_arr = lptim_time_base;
}
/* The new autoreload value must be LPTIM_GUARD_VALUE clock cycles
* after current lptim to make sure we don't miss
* an autoreload interrupt
*/
else if (next_arr < (lp_time + LPTIM_GUARD_VALUE)) {
next_arr = lp_time + LPTIM_GUARD_VALUE;
}
/* with slow lptim_clock_freq, LPTIM_GUARD_VALUE of 1 is enough */
next_arr = next_arr - 1;
/* Update autoreload register */
lptim_set_autoreload(next_arr);
k_spin_unlock(&lock, key);
}
static uint32_t sys_clock_lp_time_get(void)
{
uint32_t lp_time;
do {
/* In case of counter roll-over, add the autoreload value,
* because the irq has not yet been handled
*/
if (arrm_state_get()) {
lp_time = LL_LPTIM_GetAutoReload(LPTIM) + 1;
lp_time += z_clock_lptim_getcounter();
break;
}
lp_time = z_clock_lptim_getcounter();
/* Check if the flag ARRM wasn't be set during the process */
} while (arrm_state_get());
return lp_time;
}
uint32_t sys_clock_elapsed(void)
{
if (!IS_ENABLED(CONFIG_TICKLESS_KERNEL)) {
return 0;
}
k_spinlock_key_t key = k_spin_lock(&lock);
uint32_t lp_time = sys_clock_lp_time_get();
k_spin_unlock(&lock, key);
/* gives the value of LPTIM counter (ms)
* since the previous 'announce'
*/
uint64_t ret = ((uint64_t)lp_time * CONFIG_SYS_CLOCK_TICKS_PER_SEC) / lptim_clock_freq;
return (uint32_t)(ret);
}
uint32_t sys_clock_cycle_get_32(void)
{
/* just gives the accumulated count in a number of hw cycles */
k_spinlock_key_t key = k_spin_lock(&lock);
uint32_t lp_time = sys_clock_lp_time_get();
lp_time += accumulated_lptim_cnt;
/* convert lptim count in a nb of hw cycles with precision */
uint64_t ret = ((uint64_t)lp_time * sys_clock_hw_cycles_per_sec()) / lptim_clock_freq;
k_spin_unlock(&lock, key);
/* convert in hw cycles (keeping 32bit value) */
return (uint32_t)(ret);
}
/* Wait for the IER register of the stm32U5 ready, after any bit write operation */
void stm32_lptim_wait_ready(void)
{
#ifdef CONFIG_SOC_SERIES_STM32U5X
while (LL_LPTIM_IsActiveFlag_DIEROK(LPTIM) == 0) {
}
LL_LPTIM_ClearFlag_DIEROK(LPTIM);
#else
/* Empty : not relevant */
#endif
}
static int sys_clock_driver_init(void)
{
uint32_t count_per_tick;
int err;
if (!device_is_ready(clk_ctrl)) {
return -ENODEV;
}
/* Enable LPTIM bus clock */
err = clock_control_on(clk_ctrl, (clock_control_subsys_t) &lptim_clk[0]);
if (err < 0) {
return -EIO;
}
#if defined(LL_SRDAMR_GRP1_PERIPH_LPTIM1AMEN)
LL_SRDAMR_GRP1_EnableAutonomousClock(LL_SRDAMR_GRP1_PERIPH_LPTIM1AMEN);
#endif
/* Enable LPTIM clock source */
err = clock_control_configure(clk_ctrl,
(clock_control_subsys_t) &lptim_clk[1],
NULL);
if (err < 0) {
return -EIO;
}
/* Get LPTIM clock freq */
err = clock_control_get_rate(clk_ctrl, (clock_control_subsys_t) &lptim_clk[1],
&lptim_clock_freq);
if (err < 0) {
return -EIO;
}
#if defined(CONFIG_SOC_SERIES_STM32L0X)
/* Driver only supports freqs up to 32768Hz. On L0, LSI freq is 37KHz,
* which will overflow the LPTIM counter.
* Previous LPTIM configuration using device tree was doing forcing this
* with a Kconfig default. Impact is that time is 1.13 faster than reality.
* Following lines reproduce this behavior in order not to change behavior.
* This issue will be fixed by implementation LPTIM prescaler support.
*/
if (lptim_clk[1].bus == STM32_SRC_LSI) {
lptim_clock_freq = KHZ(32);
}
#endif
/* Set LPTIM time base based on clock source freq */
if (lptim_clock_freq == KHZ(32)) {
lptim_time_base = 0xF9FF;
} else if (lptim_clock_freq == 32768) {
lptim_time_base = 0xFFFF;
} else {
return -EIO;
}
#if !defined(CONFIG_STM32_LPTIM_TICK_FREQ_RATIO_OVERRIDE)
/*
* Check coherency between CONFIG_SYS_CLOCK_TICKS_PER_SEC
* and the lptim_clock_freq which is the CONFIG_STM32_LPTIM_CLOCK reduced
* by the lptim_clock_presc
*/
if (lptim_clock_presc <= 8) {
__ASSERT(CONFIG_STM32_LPTIM_CLOCK / 8 >= CONFIG_SYS_CLOCK_TICKS_PER_SEC,
"It is recommended to set SYS_CLOCK_TICKS_PER_SEC to CONFIG_STM32_LPTIM_CLOCK/8");
} else {
__ASSERT(CONFIG_STM32_LPTIM_CLOCK / lptim_clock_presc >=
CONFIG_SYS_CLOCK_TICKS_PER_SEC,
"Set SYS_CLOCK_TICKS_PER_SEC to CONFIG_STM32_LPTIM_CLOCK/lptim_clock_presc");
}
#endif /* !CONFIG_STM32_LPTIM_TICK_FREQ_RATIO_OVERRIDE */
/* Actual lptim clock freq when the clock source is reduced by the prescaler */
lptim_clock_freq = lptim_clock_freq / lptim_clock_presc;
/* Clear the event flag and possible pending interrupt */
IRQ_CONNECT(DT_INST_IRQN(0),
DT_INST_IRQ(0, priority),
lptim_irq_handler, 0, 0);
irq_enable(DT_INST_IRQN(0));
#ifdef CONFIG_SOC_SERIES_STM32WLX
/* Enable the LPTIM wakeup EXTI line */
LL_EXTI_EnableIT_0_31(LL_EXTI_LINE_29);
#endif
/* configure the LPTIM counter */
LL_LPTIM_SetClockSource(LPTIM, LL_LPTIM_CLK_SOURCE_INTERNAL);
/* the LPTIM clock freq is affected by the prescaler */
LL_LPTIM_SetPrescaler(LPTIM, (__CLZ(__RBIT(lptim_clock_presc)) << LPTIM_CFGR_PRESC_Pos));
#if defined(CONFIG_SOC_SERIES_STM32U5X) || \
defined(CONFIG_SOC_SERIES_STM32H5X) || \
defined(CONFIG_SOC_SERIES_STM32WBAX)
LL_LPTIM_OC_SetPolarity(LPTIM, LL_LPTIM_CHANNEL_CH1,
LL_LPTIM_OUTPUT_POLARITY_REGULAR);
#else
LL_LPTIM_SetPolarity(LPTIM, LL_LPTIM_OUTPUT_POLARITY_REGULAR);
#endif
LL_LPTIM_SetUpdateMode(LPTIM, LL_LPTIM_UPDATE_MODE_IMMEDIATE);
LL_LPTIM_SetCounterMode(LPTIM, LL_LPTIM_COUNTER_MODE_INTERNAL);
LL_LPTIM_DisableTimeout(LPTIM);
/* counting start is initiated by software */
LL_LPTIM_TrigSw(LPTIM);
#if defined(CONFIG_SOC_SERIES_STM32U5X) || \
defined(CONFIG_SOC_SERIES_STM32H5X) || \
defined(CONFIG_SOC_SERIES_STM32WBAX)
/* Enable the LPTIM before proceeding with configuration */
LL_LPTIM_Enable(LPTIM);
LL_LPTIM_DisableIT_CC1(LPTIM);
stm32_lptim_wait_ready();
LL_LPTIM_ClearFLAG_CC1(LPTIM);
#else
/* LPTIM interrupt set-up before enabling */
/* no Compare match Interrupt */
LL_LPTIM_DisableIT_CMPM(LPTIM);
LL_LPTIM_ClearFLAG_CMPM(LPTIM);
#endif
/* Autoreload match Interrupt */
LL_LPTIM_EnableIT_ARRM(LPTIM);
stm32_lptim_wait_ready();
LL_LPTIM_ClearFLAG_ARRM(LPTIM);
/* ARROK bit validates the write operation to ARR register */
LL_LPTIM_EnableIT_ARROK(LPTIM);
stm32_lptim_wait_ready();
LL_LPTIM_ClearFlag_ARROK(LPTIM);
#if !defined(CONFIG_SOC_SERIES_STM32U5X) && \
!defined(CONFIG_SOC_SERIES_STM32H5X) && \
!defined(CONFIG_SOC_SERIES_STM32WBAX)
/* Enable the LPTIM counter */
LL_LPTIM_Enable(LPTIM);
#endif
/* Set the Autoreload value once the timer is enabled */
if (IS_ENABLED(CONFIG_TICKLESS_KERNEL)) {
/* LPTIM is triggered on a LPTIM_TIMEBASE period */
lptim_set_autoreload(lptim_time_base);
} else {
/* nb of LPTIM counter unit per kernel tick (depends on lptim clock prescaler) */
count_per_tick = (lptim_clock_freq / CONFIG_SYS_CLOCK_TICKS_PER_SEC);
/* LPTIM is triggered on a Tick period */
lptim_set_autoreload(count_per_tick - 1);
}
/* Start the LPTIM counter in continuous mode */
LL_LPTIM_StartCounter(LPTIM, LL_LPTIM_OPERATING_MODE_CONTINUOUS);
#ifdef CONFIG_DEBUG
/* stop LPTIM during DEBUG */
#if defined(LL_DBGMCU_APB1_GRP1_LPTIM1_STOP)
LL_DBGMCU_APB1_GRP1_FreezePeriph(LL_DBGMCU_APB1_GRP1_LPTIM1_STOP);
#elif defined(LL_DBGMCU_APB3_GRP1_LPTIM1_STOP)
LL_DBGMCU_APB3_GRP1_FreezePeriph(LL_DBGMCU_APB3_GRP1_LPTIM1_STOP);
#endif
#endif
return 0;
}
void stm32_clock_control_standby_exit(void)
{
#ifdef CONFIG_STM32_LPTIM_STDBY_TIMER
if (clock_control_get_status(clk_ctrl,
(clock_control_subsys_t) &lptim_clk[0])
!= CLOCK_CONTROL_STATUS_ON) {
sys_clock_driver_init();
}
#endif /* CONFIG_STM32_LPTIM_STDBY_TIMER */
}
void sys_clock_idle_exit(void)
{
#ifdef CONFIG_STM32_LPTIM_STDBY_TIMER
if (timeout_stdby) {
cycle_t missed_lptim_cnt;
uint32_t stdby_timer_diff, stdby_timer_post, dticks;
uint64_t stdby_timer_us;
/* Get current value for standby timer and reset LPTIM counter value
* to start anew.
*/
LL_LPTIM_ResetCounter(LPTIM);
counter_get_value(stdby_timer, &stdby_timer_post);
/* Calculate how much time has passed since last measurement for standby timer */
/* Check IDLE timer overflow */
if (stdby_timer_pre_stdby > stdby_timer_post) {
stdby_timer_diff =
(counter_get_top_value(stdby_timer) - stdby_timer_pre_stdby) +
stdby_timer_post + 1;
} else {
stdby_timer_diff = stdby_timer_post - stdby_timer_pre_stdby;
}
stdby_timer_us = counter_ticks_to_us(stdby_timer, stdby_timer_diff);
/* Convert standby time in LPTIM cnt */
missed_lptim_cnt = (sys_clock_hw_cycles_per_sec() * stdby_timer_us) /
USEC_PER_SEC;
/* Add the LPTIM cnt pre standby */
missed_lptim_cnt += lptim_cnt_pre_stdby;
/* Update the cycle counter to include the cycles missed in standby */
accumulated_lptim_cnt += missed_lptim_cnt;
/* Announce the passed ticks to the kernel */
dticks = (missed_lptim_cnt * CONFIG_SYS_CLOCK_TICKS_PER_SEC)
/ lptim_clock_freq;
sys_clock_announce(dticks);
/* We've already performed all needed operations */
timeout_stdby = false;
}
#endif /* CONFIG_STM32_LPTIM_STDBY_TIMER */
}
SYS_INIT(sys_clock_driver_init, PRE_KERNEL_2,
CONFIG_SYSTEM_CLOCK_INIT_PRIORITY);