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* Copyright (C) 2017 Intel Corporation
*
* SPDX-License-Identifier: Apache-2.0
*/
/* Include esp-idf headers first to avoid redefining BIT() macro */
#include <soc/rtc_cntl_reg.h>
#include <soc/timer_group_reg.h>
#include <soc.h>
#include <string.h>
#include <watchdog.h>
#include <device.h>
enum wdt_mode {
WDT_MODE_RESET = 0,
WDT_MODE_INTERRUPT_RESET
};
struct wdt_esp32_data {
u32_t timeout;
enum wdt_mode mode;
wdt_callback_t callback;
struct device *dev;
};
static struct wdt_esp32_data shared_data;
/* ESP32 ignores writes to any register if WDTWPROTECT doesn't contain the
* magic value of TIMG_WDT_WKEY_VALUE. The datasheet recommends unsealing,
* making modifications, and sealing for every watchdog modification.
*/
static inline void wdt_esp32_seal(void)
{
volatile u32_t *reg = (u32_t *)TIMG_WDTWPROTECT_REG(1);
*reg = 0U;
}
static inline void wdt_esp32_unseal(void)
{
volatile u32_t *reg = (u32_t *)TIMG_WDTWPROTECT_REG(1);
*reg = TIMG_WDT_WKEY_VALUE;
}
static void wdt_esp32_enable(void)
{
volatile u32_t *reg = (u32_t *)TIMG_WDTCONFIG0_REG(1);
wdt_esp32_unseal();
*reg |= BIT(TIMG_WDT_EN_S);
wdt_esp32_seal();
}
static int wdt_esp32_disable(struct device *dev)
{
volatile u32_t *reg = (u32_t *)TIMG_WDTCONFIG0_REG(1);
ARG_UNUSED(dev);
wdt_esp32_unseal();
*reg &= ~BIT(TIMG_WDT_EN_S);
wdt_esp32_seal();
return 0;
}
static void adjust_timeout(u32_t timeout)
{
volatile u32_t *reg;
u32_t ticks = timeout;
reg = (u32_t *)TIMG_WDTCONFIG1_REG(1);
/* MWDT ticks every 12.5ns. Set the prescaler to 40000, so the
* counter for each watchdog stage is decremented every 0.5ms.
*/
*reg = 40000U;
reg = (u32_t *)TIMG_WDTCONFIG2_REG(1);
*reg = ticks;
reg = (u32_t *)TIMG_WDTCONFIG3_REG(1);
*reg = ticks;
}
static void wdt_esp32_isr(void *param);
static int wdt_esp32_reload(struct device *dev, int channel_id)
{
volatile u32_t *reg = (u32_t *)TIMG_WDTFEED_REG(1);
ARG_UNUSED(dev);
wdt_esp32_unseal();
*reg = 0xABAD1DEA; /* Writing any value to WDTFEED will reload it. */
wdt_esp32_seal();
return 0;
}
static void set_interrupt_enabled(bool setting)
{
volatile u32_t *intr_enable_reg = (u32_t *)TIMG_INT_ENA_TIMERS_REG(1);
volatile u32_t *intr_clear_timers = (u32_t *)TIMG_INT_CLR_TIMERS_REG(1);
*intr_clear_timers |= TIMG_WDT_INT_CLR;
if (setting) {
*intr_enable_reg |= TIMG_WDT_INT_ENA;
IRQ_CONNECT(CONFIG_WDT_ESP32_IRQ, 4, wdt_esp32_isr,
&shared_data, 0);
irq_enable(CONFIG_WDT_ESP32_IRQ);
} else {
*intr_enable_reg &= ~TIMG_WDT_INT_ENA;
irq_disable(CONFIG_WDT_ESP32_IRQ);
}
}
static int wdt_esp32_set_config(struct device *dev, u8_t options)
{
struct wdt_esp32_data *data = dev->driver_data;
volatile u32_t *reg = (u32_t *)TIMG_WDTCONFIG0_REG(1);
u32_t v;
if (!data) {
return -EINVAL;
}
v = *reg;
/* Stages 3 and 4 are not used: disable them. */
v |= TIMG_WDT_STG_SEL_OFF<<TIMG_WDT_STG2_S;
v |= TIMG_WDT_STG_SEL_OFF<<TIMG_WDT_STG3_S;
/* Wait for 3.2us before booting again. */
v |= 7<<TIMG_WDT_SYS_RESET_LENGTH_S;
v |= 7<<TIMG_WDT_CPU_RESET_LENGTH_S;
if (data->mode == WDT_MODE_RESET) {
/* Warm reset on timeout */
v |= TIMG_WDT_STG_SEL_RESET_SYSTEM<<TIMG_WDT_STG0_S;
v |= TIMG_WDT_STG_SEL_OFF<<TIMG_WDT_STG1_S;
/* Disable interrupts for this mode. */
v &= ~(TIMG_WDT_LEVEL_INT_EN | TIMG_WDT_EDGE_INT_EN);
} else if (data->mode == WDT_MODE_INTERRUPT_RESET) {
/* Interrupt first, and warm reset if not reloaded */
v |= TIMG_WDT_STG_SEL_INT<<TIMG_WDT_STG0_S;
v |= TIMG_WDT_STG_SEL_RESET_SYSTEM<<TIMG_WDT_STG1_S;
/* Use level-triggered interrupts. */
v |= TIMG_WDT_LEVEL_INT_EN;
v &= ~TIMG_WDT_EDGE_INT_EN;
} else {
return -EINVAL;
}
wdt_esp32_unseal();
*reg = v;
adjust_timeout(data->timeout);
set_interrupt_enabled(data->mode == WDT_MODE_INTERRUPT_RESET);
wdt_esp32_seal();
wdt_esp32_reload(dev, 0);
return 0;
}
static int wdt_esp32_install_timeout(struct device *dev,
const struct wdt_timeout_cfg *cfg)
{
struct wdt_esp32_data *data = dev->driver_data;
ARG_UNUSED(dev);
if (cfg->flags != WDT_FLAG_RESET_SOC) {
return -ENOTSUP;
}
if (cfg->window.min != 0U || cfg->window.max == 0U) {
return -EINVAL;
}
data->dev = dev;
data->timeout = cfg->window.max;
data->mode = (cfg->callback == NULL) ?
WDT_MODE_RESET : WDT_MODE_INTERRUPT_RESET;
data->callback = cfg->callback;
return 0;
}
static int wdt_esp32_init(struct device *dev)
{
#ifdef CONFIG_WDT_DISABLE_AT_BOOT
wdt_esp32_disable(dev);
#endif
/* This is a level 4 interrupt, which is handled by _Level4Vector,
* located in xtensa_vectors.S.
*/
irq_disable(CONFIG_WDT_ESP32_IRQ);
esp32_rom_intr_matrix_set(0, ETS_TG1_WDT_LEVEL_INTR_SOURCE,
CONFIG_WDT_ESP32_IRQ);
wdt_esp32_enable();
return 0;
}
static const struct wdt_driver_api wdt_api = {
.setup = wdt_esp32_set_config,
.disable = wdt_esp32_disable,
.install_timeout = wdt_esp32_install_timeout,
.feed = wdt_esp32_reload
};
DEVICE_AND_API_INIT(wdt_esp32, CONFIG_WDT_0_NAME, wdt_esp32_init,
&shared_data, NULL,
PRE_KERNEL_1, CONFIG_KERNEL_INIT_PRIORITY_DEVICE,
&wdt_api);
static void wdt_esp32_isr(void *param)
{
struct wdt_esp32_data *data = param;
volatile u32_t *reg = (u32_t *)TIMG_INT_CLR_TIMERS_REG(1);
if (shared_data.callback) {
shared_data.callback(data->dev, 0);
}
*reg |= TIMG_WDT_INT_CLR;
}
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