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cpu/sam0_common: implement RTC tamper detection

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This commit is contained in:
Benjamin Valentin 2020-07-02 00:12:48 +02:00
parent acf14f8a2b
commit 0499d016ad
2 changed files with 138 additions and 0 deletions
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26
cpu/sam0_common/include/periph_cpu_common.h
View File

@ -1069,6 +1069,32 @@ void dma_wait(dma_t dma);
void dma_cancel(dma_t dma);
/** @} */
/**
* @name sam0 RTC Tamper Detection
* @{
*/
/**
* @brief Power on the RTC (if the RTC/RTT is not otherwise used)
*/
void rtc_tamper_init(void);
/**
* @brief Enable Tamper Detection IRQs
*
* @param pin The GPIO pin to be used for tamper detection
* @param flank The Flank to trigger the even
*
* @return 0 on success, -1 if pin is not RTC pin
*/
int rtc_tamper_register(gpio_t pin, gpio_flank_t flank);
/**
* @brief Enable Tamper Detection IRQs
*/
void rtc_tamper_enable(void);
/** @} */
#ifdef __cplusplus
}
#endif

112
cpu/sam0_common/periph/rtc_rtt.c
View File

@ -25,6 +25,7 @@
*/
#include <stdint.h>
#include "mutex.h"
#include "periph/rtc.h"
#include "periph/rtt.h"
#include "periph_conf.h"
@ -101,6 +102,16 @@ static void _poweron(void)
#endif
}
__attribute__((unused))
static bool _power_is_on(void)
{
#ifdef MCLK
return MCLK->APBAMASK.reg & MCLK_APBAMASK_RTC;
#else
return PM->APBAMASK.reg & PM_APBAMASK_RTC;
#endif
}
static void _poweroff(void)
{
#ifdef MCLK
@ -268,6 +279,93 @@ void rtt_init(void)
NVIC_EnableIRQ(RTC_IRQn);
}
#if RTC_NUM_OF_TAMPERS
static rtc_state_t tamper_cb;
/* check if pin is a RTC tamper pin */
static int _rtc_pin(gpio_t pin)
{
for (unsigned i = 0; i < ARRAY_SIZE(rtc_tamper_pins); ++i) {
if (rtc_tamper_pins[i] == pin) {
return i;
}
}
return -1;
}
void rtc_tamper_init(void)
{
if (IS_ACTIVE(MODULE_PERIPH_RTC) ||
IS_ACTIVE(MODULE_PERIPH_RTT) ||
_power_is_on()) {
return;
}
_rtt_clock_setup();
_poweron();
/* disable all interrupt sources */
RTC->MODE0.INTENCLR.reg = RTC_MODE0_INTENCLR_MASK;
NVIC_EnableIRQ(RTC_IRQn);
}
int rtc_tamper_register(gpio_t pin, gpio_flank_t flank)
{
int in = _rtc_pin(pin);
if (in < 0) {
return -1;
}
/* TAMPCTRL is enable-protected */
_rtc_set_enabled(0);
RTC->MODE0.TAMPCTRL.reg |= RTC_TAMPCTRL_IN0ACT_WAKE << (2 * in);
if (flank == GPIO_RISING) {
RTC->MODE0.TAMPCTRL.reg |= RTC_TAMPCTRL_TAMLVL0 << in;
} else if (flank == GPIO_FALLING) {
RTC->MODE0.TAMPCTRL.reg &= ~(RTC_TAMPCTRL_TAMLVL0 << in);
}
/* enable the RTC again */
_rtc_set_enabled(1);
return 0;
}
static void _unlock(void *m)
{
mutex_unlock(m);
}
void rtc_tamper_enable(void)
{
mutex_t m = MUTEX_INIT;
/* clear tamper id */
RTC->MODE0.TAMPID.reg = 0xF;
/* work around errata 2.17.4:
* ignore the first tamper event on the rising edge */
if (RTC->MODE0.TAMPCTRL.reg & RTC_TAMPCTRL_TAMLVL_Msk) {
mutex_lock(&m);
tamper_cb.cb = _unlock;
tamper_cb.arg = &m;
}
/* enable tamper detect as wake-up source */
RTC->MODE0.INTENSET.bit.TAMPER = 1;
/* wait for first tamper event */
mutex_lock(&m);
}
#endif /* RTC_NUM_OF_TAMPERS */
void rtt_set_overflow_cb(rtt_cb_t cb, void *arg)
{
/* clear overflow cb to avoid race while assigning */
@ -503,9 +601,23 @@ static void _isr_rtt(void)
}
}
static void _isr_tamper(void)
{
#ifdef RTC_MODE0_INTFLAG_TAMPER
if (RTC->MODE0.INTFLAG.bit.TAMPER) {
RTC->MODE0.INTFLAG.reg = RTC_MODE0_INTFLAG_TAMPER;
if (tamper_cb.cb) {
tamper_cb.cb(tamper_cb.arg);
}
}
#endif
}
void isr_rtc(void)
{
_isr_rtc();
_isr_rtt();
_isr_tamper();
cortexm_isr_end();
}