From 16030f713ee83a680dbd0f0114acc00b7c34b4b6 Mon Sep 17 00:00:00 2001 From: Gustavo Henrique Nihei Date: Wed, 2 Mar 2022 11:11:19 -0300 Subject: [PATCH] xtensa/esp32s3: Add support for Free-running Timer Signed-off-by: Gustavo Henrique Nihei --- arch/xtensa/src/esp32s3/Kconfig | 7 + arch/xtensa/src/esp32s3/Make.defs | 4 + arch/xtensa/src/esp32s3/esp32s3_freerun.c | 365 ++++++++++++++++++++++ arch/xtensa/src/esp32s3/esp32s3_freerun.h | 145 +++++++++ 4 files changed, 521 insertions(+) create mode 100644 arch/xtensa/src/esp32s3/esp32s3_freerun.c create mode 100644 arch/xtensa/src/esp32s3/esp32s3_freerun.h diff --git a/arch/xtensa/src/esp32s3/Kconfig b/arch/xtensa/src/esp32s3/Kconfig index 33edeac5ca..3bcabf0d37 100644 --- a/arch/xtensa/src/esp32s3/Kconfig +++ b/arch/xtensa/src/esp32s3/Kconfig @@ -481,6 +481,13 @@ config ESP32S3_ONESHOT Enable a wrapper around the low level timer/counter functions to support one-shot timer. +config ESP32S3_FREERUN + bool "Free-running wrapper" + default n + ---help--- + Enable a wrapper around the low level timer/counter functions to + support a free-running timer. + endmenu # Timer/Counter Configuration config ESP32S3_TICKLESS diff --git a/arch/xtensa/src/esp32s3/Make.defs b/arch/xtensa/src/esp32s3/Make.defs index 5c33b353f6..202ac2e953 100644 --- a/arch/xtensa/src/esp32s3/Make.defs +++ b/arch/xtensa/src/esp32s3/Make.defs @@ -96,3 +96,7 @@ ifeq ($(CONFIG_ONESHOT),y) CHIP_CSRCS += esp32s3_oneshot_lowerhalf.c endif endif + +ifeq ($(CONFIG_ESP32S3_FREERUN),y) +CHIP_CSRCS += esp32s3_freerun.c +endif diff --git a/arch/xtensa/src/esp32s3/esp32s3_freerun.c b/arch/xtensa/src/esp32s3/esp32s3_freerun.c new file mode 100644 index 0000000000..73d6776a78 --- /dev/null +++ b/arch/xtensa/src/esp32s3/esp32s3_freerun.c @@ -0,0 +1,365 @@ +/**************************************************************************** + * arch/xtensa/src/esp32s3/esp32s3_freerun.c + * + * Licensed to the Apache Software Foundation (ASF) under one or more + * contributor license agreements. See the NOTICE file distributed with + * this work for additional information regarding copyright ownership. The + * ASF licenses this file to you 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. + * + ****************************************************************************/ + +/**************************************************************************** + * Included Files + ****************************************************************************/ + +#include + +#include +#include +#include +#include +#include +#include +#include + +#include +#include + +#include "esp32s3_freerun.h" +#include "esp32s3_clockconfig.h" +#include "esp32s3_gpio.h" + +#ifdef CONFIG_ESP32S3_FREERUN + +/**************************************************************************** + * Pre-processor Definitions + ****************************************************************************/ + +#define MAX_TIMERS 2 + +/* Definition for maximum resolution value in microseconds. + * Calculated according to the following algorithm: + * (PREmax * USEC_PER_SEC) / CLKmin + * where: + * PREmax == 65536, maximum supported divider in HW + * CLKmin == 80 MHz, lowest clock frequency (from APB) + */ + +#define MAX_US_RESOLUTION 819 + +#define TIMER_WIDTH 54 /* ESP32-S3 timer has 54-bit counter */ + +/**************************************************************************** + * Private Functions + ****************************************************************************/ + +/**************************************************************************** + * Name: freerun_handler + * + * Description: + * Timer interrupt callback. When the freerun timer counter overflows, + * this interrupt will occur. We will just increment an overflow counter. + * + * Input Parameters: + * irq - CPU interrupt index. + * context - Context data from the ISR. + * arg - Opaque pointer to the internal driver state structure. + * + * Returned Value: + * OK + * + ****************************************************************************/ + +#ifndef CONFIG_CLOCK_TIMEKEEPING +static int freerun_handler(int irq, void *context, void *arg) +{ + struct esp32s3_freerun_s *freerun = (struct esp32s3_freerun_s *) arg; + + DEBUGASSERT(freerun != NULL); + + freerun->overflow++; + + ESP32S3_TIM_SETALRM(freerun->tch, true); /* Re-enables the alarm */ + ESP32S3_TIM_ACKINT(freerun->tch); /* Clear the Interrupt */ + + return OK; +} +#endif /* CONFIG_CLOCK_TIMEKEEPING */ + +/**************************************************************************** + * Public Functions + ****************************************************************************/ + +/**************************************************************************** + * Name: esp32s3_freerun_initialize + * + * Description: + * Initialize the freerun timer wrapper. + * + * Input Parameters: + * freerun - Caller allocated instance of the freerun state structure. + * chan - Timer counter channel to be used. + * resolution - The required resolution of the timer in units of + * microseconds. NOTE that the range is restricted to the + * range of uint16_t (excluding zero). + * + * Returned Value: + * Zero (OK) is returned on success; a negated errno value is returned + * on failure. + * + ****************************************************************************/ + +int esp32s3_freerun_initialize(struct esp32s3_freerun_s *freerun, int chan, + uint16_t resolution) +{ + uint16_t pre; + int ret = OK; + + tmrinfo("chan=%d resolution=%d usecs\n", chan, resolution); + + DEBUGASSERT(freerun != NULL); + DEBUGASSERT(chan >= 0); + DEBUGASSERT(chan < MAX_TIMERS); + DEBUGASSERT(resolution > 0); + + /* We can't have a resolution bigger than this. + * The ESP32-S3 prescaler doesn't support. + * max resolution = (max prescaler * USEC_PER_SEC) / esp_clk_apb_freq() + */ + + DEBUGASSERT(resolution <= MAX_US_RESOLUTION); + + freerun->tch = esp32s3_tim_init(chan); + if (freerun->tch == NULL) + { + tmrerr("ERROR: Failed to allocate TIM %d\n", chan); + ret = -EBUSY; + } + else + { + /* Initialize the remaining fields in the state structure. */ + + freerun->chan = chan; + freerun->resolution = resolution; + freerun->max_timeout = (UINT64_C(1) << (TIMER_WIDTH - 1)); + + /* Ensure timer is disabled. + * Change the prescaler divider with the timer enabled can lead to + * unpredictable results. + */ + + ESP32S3_TIM_STOP(freerun->tch); + + /* Configure clock source */ + + ESP32S3_TIM_CLK_SRC(freerun->tch, ESP32S3_TIM_APB_CLK); + + /* Calculate the suitable prescaler for a period for the requested + * resolution. + */ + + pre = esp_clk_apb_freq() * resolution / USEC_PER_SEC; + + tmrinfo("pre=%" PRIu16 " clk=%d\n", pre, esp_clk_apb_freq()); + + /* Configure TIMER prescaler */ + + ESP32S3_TIM_SETPRE(freerun->tch, pre); + + /* Configure TIMER mode */ + + ESP32S3_TIM_SETMODE(freerun->tch, ESP32S3_TIM_MODE_UP); + + /* Clear TIMER counter value */ + + ESP32S3_TIM_CLEAR(freerun->tch); + + /* Set the maximum timeout */ + + ESP32S3_TIM_SETALRVL(freerun->tch, freerun->max_timeout); + +#ifndef CONFIG_CLOCK_TIMEKEEPING + + /* Set the interrupt */ + + freerun->overflow = 0; + + /* Enable autoreload */ + + ESP32S3_TIM_SETARLD(freerun->tch, true); + + /* Enable TIMER alarm */ + + ESP32S3_TIM_SETALRM(freerun->tch, true); + + /* Clear Interrupt Bits Status */ + + ESP32S3_TIM_ACKINT(freerun->tch); + + /* Register the handler */ + + { + irqstate_t flags = enter_critical_section(); + ret = ESP32S3_TIM_SETISR(freerun->tch, freerun_handler, freerun); + leave_critical_section(flags); + } + + if (ret == OK) + { + ESP32S3_TIM_ENABLEINT(freerun->tch); + } + +#endif + /* Finally, start the TIMER */ + + ESP32S3_TIM_START(freerun->tch); + } + + return ret; +} + +/**************************************************************************** + * Name: esp32s3_freerun_counter + * + * Description: + * Read the counter register of the free-running timer. + * + * Input Parameters: + * freerun - Caller allocated instance of the freerun state structure. + * This structure must have been previously initialized via a + * call to esp32s3_freerun_initialize(). + * ts - The location in which to return the time from the + * free-running timer. + * + * Returned Value: + * Zero (OK) is returned on success; a negated errno value is returned + * on failure. + * + ****************************************************************************/ + +#ifndef CONFIG_CLOCK_TIMEKEEPING + +int esp32s3_freerun_counter(struct esp32s3_freerun_s *freerun, + struct timespec *ts) +{ + uint64_t usec; + uint64_t counter; + uint64_t verify; + uint32_t overflow; + uint32_t sec; + int pending; + irqstate_t flags; + + DEBUGASSERT(freerun != NULL); + DEBUGASSERT(ts != NULL); + DEBUGASSERT(freerun->tch != NULL); + + /* Temporarily disable the overflow counter. */ + + flags = enter_critical_section(); + + overflow = freerun->overflow; + ESP32S3_TIM_GETCTR(freerun->tch, &counter); + pending = ESP32S3_TIM_CHECKINT(freerun->tch); + ESP32S3_TIM_GETCTR(freerun->tch, &verify); + + /* If an interrupt was pending before we re-enabled interrupts, then the + * overflow needs to be incremented. + */ + + if (pending) + { + ESP32S3_TIM_ACKINT(freerun->tch); + + /* Increment the overflow count and use the value of the guaranteed to + * be AFTER the overflow occurred. + */ + + overflow++; + counter = verify; + + /* Update freerun overflow counter. */ + + freerun->overflow = overflow; + } + + leave_critical_section(flags); + + tmrinfo("counter=%" PRIu64 " (%" PRIu64 ") overflow=%" PRIu32 + ", pending=%i\n", + counter, verify, overflow, pending); + + usec = (uint64_t)(((overflow * freerun->max_timeout) + counter) + * freerun->resolution); + + /* And return the value of the timer */ + + sec = (uint32_t)(usec / USEC_PER_SEC); + ts->tv_sec = sec; + ts->tv_nsec = (usec - (sec * USEC_PER_SEC)) * NSEC_PER_USEC; + + tmrinfo(" usec=%" PRIu64 " ts=(%lu, %lu)\n", + usec, (unsigned long)ts->tv_sec, (unsigned long)ts->tv_nsec); + + return OK; +} + +#endif /* CONFIG_CLOCK_TIMEKEEPING */ + +/**************************************************************************** + * Name: esp32s3_freerun_uninitialize + * + * Description: + * Stop the free-running timer and release all resources that it uses. + * + * Input Parameters: + * freerun - Caller allocated instance of the freerun state structure. + * This structure must have been previously initialized via a + * call to esp32s3_freerun_initialize(). + * + * Returned Value: + * Zero (OK) is returned on success; a negated errno value is returned + * on failure. + * + ****************************************************************************/ + +int esp32s3_freerun_uninitialize(struct esp32s3_freerun_s *freerun) +{ + int ret; + + DEBUGASSERT(freerun != NULL); + DEBUGASSERT(freerun->tch != NULL); + + tmrinfo("chan=%d\n", freerun->chan); + + /* Stop timer */ + + ESP32S3_TIM_STOP(freerun->tch); + + /* Disable timer interrupt */ + + ESP32S3_TIM_DISABLEINT(freerun->tch); + + /* Detach handler */ + + ret = ESP32S3_TIM_SETISR(freerun->tch, NULL, NULL); + + /* Free the timer */ + + esp32s3_tim_deinit(freerun->tch); + freerun->tch = NULL; + + return ret; +} + +#endif /* CONFIG_ESP32S3_FREERUN */ diff --git a/arch/xtensa/src/esp32s3/esp32s3_freerun.h b/arch/xtensa/src/esp32s3/esp32s3_freerun.h new file mode 100644 index 0000000000..b2016d5b6c --- /dev/null +++ b/arch/xtensa/src/esp32s3/esp32s3_freerun.h @@ -0,0 +1,145 @@ +/**************************************************************************** + * arch/xtensa/src/esp32s3/esp32s3_freerun.h + * + * Licensed to the Apache Software Foundation (ASF) under one or more + * contributor license agreements. See the NOTICE file distributed with + * this work for additional information regarding copyright ownership. The + * ASF licenses this file to you 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. + * + ****************************************************************************/ + +#ifndef __ARCH_XTENSA_SRC_ESP32S3_ESP32S3_FREERUN_H +#define __ARCH_XTENSA_SRC_ESP32S3_ESP32S3_FREERUN_H + +/**************************************************************************** + * Included Files + ****************************************************************************/ + +#include + +#include +#include + +#include "esp32s3_tim.h" + +#ifdef CONFIG_ESP32S3_FREERUN + +/**************************************************************************** + * Public Types + ****************************************************************************/ + +/* The freerun client must allocate an instance of this structure and called + * esp32s3_freerun_initialize() before using the freerun facilities. The + * client should not access the contents of this structure directly since + * the contents are subject to change. + */ + +struct esp32s3_freerun_s +{ + uint8_t chan; /* The timer/counter in use */ + uint32_t overflow; /* Timer counter overflow */ + uint16_t resolution; /* Timer resolution */ + uint64_t max_timeout; /* Maximum timeout to overflow */ + struct esp32s3_tim_dev_s *tch; /* Handle returned by esp32s3_tim_init() */ +}; + +/**************************************************************************** + * Public Data + ****************************************************************************/ + +#undef EXTERN +#if defined(__cplusplus) +#define EXTERN extern "C" +extern "C" +{ +#else +#define EXTERN extern +#endif + +/**************************************************************************** + * Public Function Prototypes + ****************************************************************************/ + +/**************************************************************************** + * Name: esp32s3_freerun_initialize + * + * Description: + * Initialize the freerun timer wrapper. + * + * Input Parameters: + * freerun - Caller allocated instance of the freerun + * state structure + * chan - Timer counter channel to be used. + * resolution - The required resolution of the timer in units of + * microseconds. NOTE that the range is restricted to + * the range of uint16_t (excluding zero). + * + * Returned Value: + * Zero (OK) is returned on success; a negated errno value is returned + * on failure. + * + ****************************************************************************/ + +int esp32s3_freerun_initialize(struct esp32s3_freerun_s *freerun, int chan, + uint16_t resolution); + +/**************************************************************************** + * Name: esp32s3_freerun_counter + * + * Description: + * Read the counter register of the free-running timer. + * + * Input Parameters: + * freerun - Caller allocated instance of the freerun state + * structure. This structure must have been previously + * initialized via a call to + * esp32s3_freerun_initialize(); + * ts - The location in which to return the time from the + * free-running timer. + * + * Returned Value: + * Zero (OK) is returned on success; a negated errno value is returned + * on failure. + * + ****************************************************************************/ + +int esp32s3_freerun_counter(struct esp32s3_freerun_s *freerun, + struct timespec *ts); + +/**************************************************************************** + * Name: esp32s3_freerun_uninitialize + * + * Description: + * Stop the free-running timer and release all resources that it uses. + * + * Input Parameters: + * freerun - Caller allocated instance of the freerun state + * structure. This structure must have been previously + * initialized via a call to + * esp32s3_freerun_initialize(); + * + * Returned Value: + * Zero (OK) is returned on success; a negated errno value is returned + * on failure. + * + ****************************************************************************/ + +int esp32s3_freerun_uninitialize(struct esp32s3_freerun_s *freerun); + +#undef EXTERN +#ifdef __cplusplus +} +#endif + +#endif /* CONFIG_ESP32S3_FREERUN */ +#endif /* __ARCH_XTENSA_SRC_ESP32S3_ESP32S3_FREERUN_H */