esp-idf/components/esp32/dport_access.c

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// Copyright 2010-2017 Espressif Systems (Shanghai) PTE LTD
//
// 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.
/*
* DPORT access is used for do protection when dual core access DPORT internal register and APB register via DPORT simultaneously
* This function will be initialize after FreeRTOS startup.
* When cpu0 want to access DPORT register, it should notify cpu1 enter in high-priority interrupt for be mute. When cpu1 already in high-priority interrupt,
* cpu0 can access DPORT register. Currently, cpu1 will wait for cpu0 finish access and exit high-priority interrupt.
*/
#include <stdint.h>
#include <string.h>
#include "esp_attr.h"
#include "esp_err.h"
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#include "esp_intr_alloc.h"
#include "soc/cpu.h"
#include "soc/dport_reg.h"
#include "soc/spi_periph.h"
#include "hal/cpu_hal.h"
#include "freertos/FreeRTOS.h"
#include "freertos/task.h"
#include "freertos/semphr.h"
#include "freertos/queue.h"
#include "sdkconfig.h"
#ifndef CONFIG_FREERTOS_UNICORE
static portMUX_TYPE g_dport_mux = portMUX_INITIALIZER_UNLOCKED;
#define DPORT_CORE_STATE_IDLE 0
#define DPORT_CORE_STATE_RUNNING 1
static uint32_t volatile dport_core_state[portNUM_PROCESSORS]; //cpu is already run
/* these global variables are accessed from interrupt vector, hence not declared as static */
uint32_t volatile dport_access_start[portNUM_PROCESSORS]; //dport register could be accessed
uint32_t volatile dport_access_end[portNUM_PROCESSORS]; //dport register is accessed over
static uint32_t volatile dport_access_ref[portNUM_PROCESSORS]; //dport access reference
#ifdef DPORT_ACCESS_BENCHMARK
#define DPORT_ACCESS_BENCHMARK_STORE_NUM
static uint32_t ccount_start[portNUM_PROCESSORS];
static uint32_t ccount_end[portNUM_PROCESSORS];
static uint32_t ccount_margin[portNUM_PROCESSORS][DPORT_ACCESS_BENCHMARK_STORE_NUM];
static uint32_t ccount_margin_cnt;
#endif
static BaseType_t oldInterruptLevel[2];
#endif // CONFIG_FREERTOS_UNICORE
/* stall other cpu that this cpu is pending to access dport register start */
void IRAM_ATTR esp_dport_access_stall_other_cpu_start(void)
{
#ifndef CONFIG_FREERTOS_UNICORE
if (dport_core_state[0] == DPORT_CORE_STATE_IDLE
|| dport_core_state[1] == DPORT_CORE_STATE_IDLE) {
return;
}
BaseType_t intLvl = portENTER_CRITICAL_NESTED();
int cpu_id = xPortGetCoreID();
#ifdef DPORT_ACCESS_BENCHMARK
ccount_start[cpu_id] = cpu_hal_get_cycle_count();
#endif
if (dport_access_ref[cpu_id] == 0) {
portENTER_CRITICAL_ISR(&g_dport_mux);
oldInterruptLevel[cpu_id]=intLvl;
dport_access_start[cpu_id] = 0;
dport_access_end[cpu_id] = 0;
if (cpu_id == 0) {
_DPORT_REG_WRITE(DPORT_CPU_INTR_FROM_CPU_3_REG, DPORT_CPU_INTR_FROM_CPU_3); //interrupt on cpu1
} else {
_DPORT_REG_WRITE(DPORT_CPU_INTR_FROM_CPU_2_REG, DPORT_CPU_INTR_FROM_CPU_2); //interrupt on cpu0
}
while (!dport_access_start[cpu_id]) {};
REG_READ(SPI_DATE_REG(3)); //just read a APB register sure that the APB-bus is idle
}
dport_access_ref[cpu_id]++;
if (dport_access_ref[cpu_id] > 1) {
/* Interrupts are already disabled by the parent, we're nested here. */
portEXIT_CRITICAL_NESTED(intLvl);
}
#endif /* CONFIG_FREERTOS_UNICORE */
}
/* stall other cpu that this cpu is pending to access dport register end */
void IRAM_ATTR esp_dport_access_stall_other_cpu_end(void)
{
#ifndef CONFIG_FREERTOS_UNICORE
int cpu_id = xPortGetCoreID();
if (dport_core_state[0] == DPORT_CORE_STATE_IDLE
|| dport_core_state[1] == DPORT_CORE_STATE_IDLE) {
return;
}
if (dport_access_ref[cpu_id] == 0) {
assert(0);
}
dport_access_ref[cpu_id]--;
if (dport_access_ref[cpu_id] == 0) {
dport_access_end[cpu_id] = 1;
portEXIT_CRITICAL_ISR(&g_dport_mux);
portEXIT_CRITICAL_NESTED(oldInterruptLevel[cpu_id]);
}
#ifdef DPORT_ACCESS_BENCHMARK
ccount_end[cpu_id] = cpu_hal_get_cycle_count();
ccount_margin[cpu_id][ccount_margin_cnt] = ccount_end[cpu_id] - ccount_start[cpu_id];
ccount_margin_cnt = (ccount_margin_cnt + 1)&(DPORT_ACCESS_BENCHMARK_STORE_NUM - 1);
#endif
#endif /* CONFIG_FREERTOS_UNICORE */
}
#ifndef CONFIG_FREERTOS_UNICORE
static void dport_access_init_core(void *arg)
{
int core_id = 0;
uint32_t intr_source = ETS_FROM_CPU_INTR2_SOURCE;
core_id = xPortGetCoreID();
if (core_id == 1) {
intr_source = ETS_FROM_CPU_INTR3_SOURCE;
}
ESP_INTR_DISABLE(ETS_DPORT_INUM);
intr_matrix_set(core_id, intr_source, ETS_DPORT_INUM);
ESP_INTR_ENABLE(ETS_DPORT_INUM);
dport_access_ref[core_id] = 0;
dport_access_start[core_id] = 0;
dport_access_end[core_id] = 0;
dport_core_state[core_id] = DPORT_CORE_STATE_RUNNING;
/* If this fails then the minimum stack size for this config is too close to running out */
assert(uxTaskGetStackHighWaterMark(NULL) > 128);
vTaskDelete(NULL);
}
#endif
/* Defer initialisation until after scheduler is running */
void esp_dport_access_int_init(void)
{
#ifndef CONFIG_FREERTOS_UNICORE
portBASE_TYPE res = xTaskCreatePinnedToCore(&dport_access_init_core, "dport", configMINIMAL_STACK_SIZE, NULL, 5, NULL, xPortGetCoreID());
assert(res == pdTRUE);
(void)res;
#endif
}
void IRAM_ATTR esp_dport_access_int_pause(void)
{
#ifndef CONFIG_FREERTOS_UNICORE
portENTER_CRITICAL_ISR(&g_dport_mux);
dport_core_state[0] = DPORT_CORE_STATE_IDLE;
dport_core_state[1] = DPORT_CORE_STATE_IDLE;
portEXIT_CRITICAL_ISR(&g_dport_mux);
#endif
}
//Used in panic code: the enter_critical stuff may be messed up so we just stop everything without checking the mux.
void IRAM_ATTR esp_dport_access_int_abort(void)
{
#ifndef CONFIG_FREERTOS_UNICORE
dport_core_state[0] = DPORT_CORE_STATE_IDLE;
dport_core_state[1] = DPORT_CORE_STATE_IDLE;
#endif
}
void IRAM_ATTR esp_dport_access_int_resume(void)
{
#ifndef CONFIG_FREERTOS_UNICORE
portENTER_CRITICAL_ISR(&g_dport_mux);
dport_core_state[0] = DPORT_CORE_STATE_RUNNING;
dport_core_state[1] = DPORT_CORE_STATE_RUNNING;
portEXIT_CRITICAL_ISR(&g_dport_mux);
#endif
}
/**
* @brief Read a sequence of DPORT registers to the buffer, SMP-safe version.
*
* This implementation uses a method of the pre-reading of the APB register
* before reading the register of the DPORT, without stall other CPU.
* There is disable/enable interrupt.
*
* @param[out] buff_out Contains the read data.
* @param[in] address Initial address for reading registers.
* @param[in] num_words The number of words.
*/
void IRAM_ATTR esp_dport_access_read_buffer(uint32_t *buff_out, uint32_t address, uint32_t num_words)
{
DPORT_INTERRUPT_DISABLE();
for (uint32_t i = 0; i < num_words; ++i) {
buff_out[i] = DPORT_SEQUENCE_REG_READ(address + i * 4);
}
DPORT_INTERRUPT_RESTORE();
}
/**
* @brief Read value from register, SMP-safe version.
*
* This method uses the pre-reading of the APB register before reading the register of the DPORT.
* This implementation is useful for reading DORT registers for single reading without stall other CPU.
* There is disable/enable interrupt.
*
* @param reg Register address
* @return Value
*/
uint32_t IRAM_ATTR esp_dport_access_reg_read(uint32_t reg)
{
#if defined(BOOTLOADER_BUILD) || !defined(CONFIG_ESP32_DPORT_WORKAROUND) || !defined(ESP_PLATFORM)
return _DPORT_REG_READ(reg);
#else
uint32_t apb;
unsigned int intLvl;
__asm__ __volatile__ (\
"rsil %[LVL], "XTSTR(CONFIG_ESP32_DPORT_DIS_INTERRUPT_LVL)"\n"\
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"movi %[APB], "XTSTR(0x3ff40078)"\n"\
"l32i %[APB], %[APB], 0\n"\
"l32i %[REG], %[REG], 0\n"\
"wsr %[LVL], "XTSTR(PS)"\n"\
"rsync\n"\
: [APB]"=a"(apb), [REG]"+a"(reg), [LVL]"=a"(intLvl)\
: \
: "memory" \
);
return reg;
#endif
}
/**
* @brief Read value from register, NOT SMP-safe version.
*
* This method uses the pre-reading of the APB register before reading the register of the DPORT.
* There is not disable/enable interrupt.
* The difference from DPORT_REG_READ() is that the user himself must disable interrupts while DPORT reading.
* This implementation is useful for reading DORT registers in loop without stall other CPU. Note the usage example.
* The recommended way to read registers sequentially without stall other CPU
* is to use the method esp_dport_read_buffer(buff_out, address, num_words). It allows you to read registers in the buffer.
*
* \code{c}
* // This example shows how to use it.
* { // Use curly brackets to limit the visibility of variables in macros DPORT_INTERRUPT_DISABLE/RESTORE.
* DPORT_INTERRUPT_DISABLE(); // Disable interrupt only on current CPU.
* for (i = 0; i < max; ++i) {
* array[i] = esp_dport_access_sequence_reg_read(Address + i * 4); // reading DPORT registers
* }
* DPORT_INTERRUPT_RESTORE(); // restore the previous interrupt level
* }
* \endcode
*
* @param reg Register address
* @return Value
*/
uint32_t IRAM_ATTR esp_dport_access_sequence_reg_read(uint32_t reg)
{
#if defined(BOOTLOADER_BUILD) || !defined(CONFIG_ESP32_DPORT_WORKAROUND) || !defined(ESP_PLATFORM)
return _DPORT_REG_READ(reg);
#else
uint32_t apb;
__asm__ __volatile__ (\
"movi %[APB], "XTSTR(0x3ff40078)"\n"\
"l32i %[APB], %[APB], 0\n"\
"l32i %[REG], %[REG], 0\n"\
: [APB]"=a"(apb), [REG]"+a"(reg)\
: \
: "memory" \
);
return reg;
#endif
}