esp_common: Add API for IPC to run small pieces of code on the other CPU, in the context of the level 4 interrupt

.gitlab/ci/target-test.yml

@@ -97,7 +97,7 @@ example_test_001B_V3:
 
 example_test_001C:
   extends: .example_test_esp32_template
-  parallel: 3
+  parallel: 4
   tags:
     - ESP32
     - Example_GENERIC

components/esp_hw_support/CMakeLists.txt

@@ -1,6 +1,5 @@
 idf_build_get_property(target IDF_TARGET)
 
-set(priv_requires efuse)
 set(requires soc)
 set(priv_requires efuse bootloader_support spi_flash)
 if(${target} STREQUAL "esp32")
@@ -17,7 +16,7 @@ if(NOT BOOTLOADER_BUILD)
                      "mac_addr.c"
                      "sleep_modes.c"
                      "regi2c_ctrl.c")
-    list(APPEND priv_requires esp_ipc)
+    list(APPEND requires esp_ipc)
 else()
     # Requires "_esp_error_check_failed()" function
     list(APPEND priv_requires "esp_system")

components/esp_hw_support/include/soc/esp32/dport_access.h

@@ -3,30 +3,28 @@
  *
  * SPDX-License-Identifier: Apache-2.0
  */
+
+#pragma once
+
 #include <stdint.h>
-
 #include <sdkconfig.h>
-
-#ifndef _ESP_DPORT_ACCESS_H_
-#define _ESP_DPORT_ACCESS_H_
-
 #include "xtensa/xtruntime.h"
 
 #ifdef __cplusplus
 extern "C" {
 #endif
 
-void esp_dport_access_stall_other_cpu_start(void);
+void esp_dport_access_stall_other_cpu_start(void) __attribute__ ((deprecated));
-void esp_dport_access_stall_other_cpu_end(void);
+void esp_dport_access_stall_other_cpu_end(void) __attribute__ ((deprecated));
-void esp_dport_access_int_init(void);
+void esp_dport_access_int_init(void) __attribute__ ((deprecated));
-void esp_dport_access_int_pause(void);
+void esp_dport_access_int_pause(void) __attribute__ ((deprecated));
-void esp_dport_access_int_resume(void);
+void esp_dport_access_int_resume(void) __attribute__ ((deprecated));
 void esp_dport_access_read_buffer(uint32_t *buff_out, uint32_t address, uint32_t num_words);
 uint32_t esp_dport_access_reg_read(uint32_t reg);
 uint32_t esp_dport_access_sequence_reg_read(uint32_t reg);
 //This routine does not stop the dport routines in any way that is recoverable. Please
 //only call in case of panic().
-void esp_dport_access_int_abort(void);
+void esp_dport_access_int_abort(void) __attribute__ ((deprecated));
 
 #if defined(BOOTLOADER_BUILD) || !defined(CONFIG_ESP32_DPORT_WORKAROUND) || !defined(ESP_PLATFORM)
 #define DPORT_STALL_OTHER_CPU_START()
@@ -34,8 +32,9 @@ void esp_dport_access_int_abort(void);
 #define DPORT_INTERRUPT_DISABLE()
 #define DPORT_INTERRUPT_RESTORE()
 #else
-#define DPORT_STALL_OTHER_CPU_START()   esp_dport_access_stall_other_cpu_start()
+#include "esp_ipc_isr.h"
-#define DPORT_STALL_OTHER_CPU_END()     esp_dport_access_stall_other_cpu_end()
+#define DPORT_STALL_OTHER_CPU_START()   esp_ipc_isr_stall_other_cpu()
+#define DPORT_STALL_OTHER_CPU_END()     esp_ipc_isr_release_other_cpu()
 #define DPORT_INTERRUPT_DISABLE()       unsigned int intLvl = XTOS_SET_INTLEVEL(CONFIG_ESP32_DPORT_DIS_INTERRUPT_LVL)
 #define DPORT_INTERRUPT_RESTORE()       XTOS_RESTORE_JUST_INTLEVEL(intLvl)
 #endif
@@ -43,5 +42,3 @@ void esp_dport_access_int_abort(void);
 #ifdef __cplusplus
 }
 #endif
-
-#endif /* _ESP_DPORT_ACCESS_H_ */

components/esp_hw_support/port/esp32/dport_access.c

@@ -4,202 +4,11 @@
  * SPDX-License-Identifier: Apache-2.0
  */
 
-/*
- * 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 <sdkconfig.h>
-#include "esp_attr.h"
-#include "esp_err.h"
-#include "esp_intr_alloc.h"
-
-#include "soc/cpu.h"
 #include "soc/dport_reg.h"
-#include "soc/spi_periph.h"
+#include "xtensa/core-macros.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.

components/esp_hw_support/sleep_modes.c

@@ -24,6 +24,7 @@
 #include "esp_log.h"
 #include "esp_newlib.h"
 #include "esp_timer.h"
+#include "esp_ipc_isr.h"
 #include "freertos/FreeRTOS.h"
 #include "freertos/task.h"
 #include "soc/soc_caps.h"
@@ -701,7 +702,7 @@ esp_err_t esp_light_sleep_start(void)
     uint64_t frc_time_at_start = esp_system_get_time();
     uint32_t sleep_time_overhead_in = (ccount_at_sleep_start - s_config.ccount_ticks_record) / (esp_clk_cpu_freq() / 1000000ULL);
 
-    DPORT_STALL_OTHER_CPU_START();
+    esp_ipc_isr_stall_other_cpu();
 
     // Decide which power domains can be powered down
     uint32_t pd_flags = get_power_down_flags();
@@ -825,7 +826,7 @@ esp_err_t esp_light_sleep_start(void)
     esp_set_time_from_rtc();
 
     esp_timer_private_unlock();
-    DPORT_STALL_OTHER_CPU_END();
+    esp_ipc_isr_release_other_cpu();
     if (!wdt_was_enabled) {
         wdt_hal_write_protect_disable(&rtc_wdt_ctx);
         wdt_hal_disable(&rtc_wdt_ctx);

components/esp_ipc/CMakeLists.txt

@@ -1,2 +1,10 @@
-idf_component_register(SRCS "ipc.c"
+set(srcs "src/esp_ipc.c")
+
+if(CONFIG_ESP_IPC_ISR_ENABLE)
+    list(APPEND srcs "src/esp_ipc_isr/esp_ipc_isr.c"
+                    "src/esp_ipc_isr/esp_ipc_isr_handler.S"
+                    "src/esp_ipc_isr/esp_ipc_isr_routines.S")
+endif()
+
+idf_component_register(SRCS "${srcs}"
                     INCLUDE_DIRS "include")

components/esp_ipc/Kconfig

@@ -0,0 +1,39 @@
+menu "IPC (Inter-Processor Call)"
+
+    config ESP_IPC_TASK_STACK_SIZE
+        int "Inter-Processor Call (IPC) task stack size"
+        range 512 65536 if !APPTRACE_ENABLE
+        range 2048 65536 if APPTRACE_ENABLE
+        default 2048 if APPTRACE_ENABLE
+        default 1024
+        help
+            Configure the IPC tasks stack size. One IPC task runs on each core
+            (in dual core mode), and allows for cross-core function calls.
+
+            See IPC documentation for more details.
+
+            The default stack size should be enough for most common use cases.
+            It can be shrunk if you are sure that you do not use any custom
+            IPC functionality.
+
+    config ESP_IPC_USES_CALLERS_PRIORITY
+        bool "IPC runs at caller's priority"
+        default y
+        depends on !FREERTOS_UNICORE
+        help
+            If this option is not enabled then the IPC task will keep behavior
+            same as prior to that of ESP-IDF v4.0, and hence IPC task will run
+            at (configMAX_PRIORITIES - 1) priority.
+
+    config ESP_IPC_ISR_ENABLE
+        bool
+        default y if !FREERTOS_UNICORE
+        help
+            This feature servers a similar purpose to the IPC except that the callback function is run
+            in the context of a level 4 interrupt (i.e., high priority/level interrupt). The IPC ISR
+            feature is intended for low latency execution of simple functions written in assembly on
+            another CPU. Due to being run in higher level interrupt context, the assembly functions
+            should be written in a particular way (see esp_test_ipc_isr_asm() and the "High-Level Interrupts"
+            chapter in hlinterrupts.rst for more details).
+
+endmenu # "IPC (Inter-Processor Call)

components/esp_ipc/component.mk

@@ -1,3 +1,9 @@
 #
 # Component Makefile
 #
+
+COMPONENT_SRCDIRS := src
+ifdef CONFIG_ESP_IPC_ISR_ENABLE
+    COMPONENT_SRCDIRS += src/esp_ipc_isr
+endif
+COMPONENT_ADD_INCLUDEDIRS := include

components/esp_ipc/include/esp_ipc.h

@@ -20,6 +20,9 @@
 #ifdef __cplusplus
 extern "C" {
 #endif
+
+#ifndef CONFIG_FREERTOS_UNICORE
+
 /** @cond */
 typedef void (*esp_ipc_func_t)(void* arg);
 /** @endcond */
@@ -85,6 +88,7 @@ esp_err_t esp_ipc_call(uint32_t cpu_id, esp_ipc_func_t func, void* arg);
  */
 esp_err_t esp_ipc_call_blocking(uint32_t cpu_id, esp_ipc_func_t func, void* arg);
 
+#endif // not CONFIG_FREERTOS_UNICORE
 
 #ifdef __cplusplus
 }

components/esp_ipc/include/esp_ipc_isr.h

@@ -0,0 +1,117 @@
+/*
+ * SPDX-FileCopyrightText: 2015-2021 Espressif Systems (Shanghai) CO LTD
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#pragma once
+
+#include "sdkconfig.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#ifdef CONFIG_ESP_IPC_ISR_ENABLE
+
+/** @cond */
+typedef void (*esp_ipc_isr_func_t)(void* arg);
+/** @endcond */
+
+/**
+ * @brief Initialize inter-processor call module which based on #4 high-interrupt.
+ *
+ * This function is called on CPU start and should not be called from the application.
+ *
+ * This function starts two tasks, one on each CPU. These tasks register
+ * #4 High-interrupt and after that, the tasks are deleted.
+ * The next API functions work with this functionality:
+ * esp_ipc_isr_asm_call
+ * esp_ipc_isr_asm_call_blocking
+ * They allow to run an asm function on other CPU.
+ */
+void esp_ipc_isr_init(void);
+
+/**
+ * @brief Execute an asm function on the other CPU (uses the #4 high-priority interrupt)
+ *
+ * @note In single-core mode, it is not available.
+ * This function calls the #4 high-priority interrupt on the other CPU.
+ * The given function is called in the context of the interrupt by CALLX0 command and
+ * operates with registers a2, a3, a4.
+ *
+ * @param[in]   func    Pointer to a function of type void func(void* arg) to be executed
+ * @param[in]   arg     Arbitrary argument of type void* to be passed into the function
+ */
+void esp_ipc_isr_asm_call(esp_ipc_isr_func_t func, void* arg);
+
+/**
+ * @brief Execute an asm function on the other CPU and blocks until it completes (uses the #4 high-priority interrupt)
+ *
+ * @note In single-core mode, it is not available.
+ * This function calls the #4 high-priority interrupt on the other CPU.
+ * The given function is called in the context of the interrupt by CALLX0 command.
+ *
+ * @param[in]   func    Pointer to a function of type void func(void* arg) to be executed
+ * @param[in]   arg     Arbitrary argument of type void* to be passed into the function
+ */
+void esp_ipc_isr_asm_call_blocking(esp_ipc_isr_func_t func, void* arg);
+
+/**
+ * @brief Stall the other CPU and the current CPU disables interrupts with level 3 and lower.
+ *
+ * @note In single-core mode, it is not available.
+ * This function calls the #4 high-priority interrupt on the other CPU.
+ * The esp_ipc_isr_finish_cmd() function is called on the other CPU in the context of the #4 high-priority interrupt.
+ * The esp_ipc_isr_finish_cmd is called by CALLX0 command.
+ * It is waiting for the end command. The command will be sent by esp_ipc_isr_release_other_cpu().
+ * This function is used for DPORT workaround.
+ *
+ * This function blocks other CPU until the release call esp_ipc_isr_release_other_cpu().
+ *
+ * This fucntion is used for the DPORT workaround: stall other cpu that this cpu is pending to access dport register start.
+ */
+void esp_ipc_isr_stall_other_cpu(void);
+
+/**
+ * @brief Release the other CPU
+ *
+ * @note In single-core mode, it is not available.
+ * This function will send the end command to release the stall other CPU.
+ * This function is used for DPORT workaround: stall other cpu that this cpu is pending to access dport register end.
+ *
+ */
+void esp_ipc_isr_release_other_cpu(void);
+
+/**
+ * @brief Pause stall the other CPU
+ */
+void esp_ipc_isr_stall_pause(void);
+
+/**
+ * @brief Abort stall the other CPU
+ *
+ * This routine does not stop the stall routines in any way that is recoverable.
+ * Please only call in case of panic().
+ * Used in panic code: the enter_critical stuff may be messed up so we just stop everything without checking the mux.
+ */
+void esp_ipc_isr_stall_abort(void);
+
+/**
+ * @brief Resume stall the other CPU
+ */
+void esp_ipc_isr_stall_resume(void);
+
+#else // not CONFIG_ESP_IPC_ISR_ENABLE
+
+#define esp_ipc_isr_stall_other_cpu()
+#define esp_ipc_isr_release_other_cpu()
+#define esp_ipc_isr_stall_pause()
+#define esp_ipc_isr_stall_abort()
+#define esp_ipc_isr_stall_resume()
+
+#endif // CONFIG_ESP_IPC_ISR_ENABLE
+
+#ifdef __cplusplus
+}
+#endif

components/esp_ipc/src/esp_ipc.c

@@ -18,12 +18,15 @@
 #include <assert.h>
 #include "esp_err.h"
 #include "esp_ipc.h"
+#include "esp_ipc_isr.h"
 #include "esp_attr.h"
 
 #include "freertos/FreeRTOS.h"
 #include "freertos/task.h"
 #include "freertos/semphr.h"
 
+#ifndef CONFIG_FREERTOS_UNICORE
+
 static TaskHandle_t s_ipc_task_handle[portNUM_PROCESSORS];
 static SemaphoreHandle_t s_ipc_mutex[portNUM_PROCESSORS];    // This mutex is used as a global lock for esp_ipc_* APIs
 static SemaphoreHandle_t s_ipc_sem[portNUM_PROCESSORS];      // Two semaphores used to wake each of ipc tasks
@@ -86,6 +89,9 @@ static void esp_ipc_init(void) __attribute__((constructor));
 
 static void esp_ipc_init(void)
 {
+#ifdef CONFIG_ESP_IPC_ISR_ENABLE
+	esp_ipc_isr_init();
+#endif
     char task_name[15];
     for (int i = 0; i < portNUM_PROCESSORS; ++i) {
         snprintf(task_name, sizeof(task_name), "ipc%d", i);
@@ -144,3 +150,5 @@ esp_err_t esp_ipc_call_blocking(uint32_t cpu_id, esp_ipc_func_t func, void* arg)
 {
     return esp_ipc_call_and_wait(cpu_id, func, arg, IPC_WAIT_FOR_END);
 }
+
+#endif // not CONFIG_FREERTOS_UNICORE

components/esp_ipc/src/esp_ipc_isr/esp_ipc_isr.c

@@ -0,0 +1,215 @@
+/*
+ * SPDX-FileCopyrightText: 2017-2021 Espressif Systems (Shanghai) CO LTD
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <stddef.h>
+#include <stdlib.h>
+#include <string.h>
+#include <assert.h>
+#include "esp_err.h"
+#include "esp_attr.h"
+#include "soc/cpu.h"
+#include "soc/soc.h"
+#include "soc/dport_access.h"
+#ifdef CONFIG_IDF_TARGET_ESP32
+#include "soc/dport_reg.h"
+#else
+#include "soc/periph_defs.h"
+#include "soc/system_reg.h"
+#endif
+#include "freertos/FreeRTOS.h"
+#include "freertos/task.h"
+#include "freertos/portmacro.h"
+#include "esp_intr_alloc.h"
+#include "esp_ipc_isr.h"
+#include "xtensa/core-macros.h"
+#include "sdkconfig.h"
+
+static portMUX_TYPE s_ipc_isr_mux = portMUX_INITIALIZER_UNLOCKED;
+uint32_t volatile esp_ipc_isr_start_fl;        // the flag shows that it is about to run esp_ipc_func()
+uint32_t volatile esp_ipc_isr_end_fl = 1;      // the flag shows that esp_ipc_func() is done
+esp_ipc_isr_func_t volatile esp_ipc_func;      // the function which will be run in the ipc_isr context
+void * volatile esp_ipc_func_arg;              // the argument of esp_ipc_func()
+
+typedef enum {
+    STALL_STATE_IDLE      = 0,
+    STALL_STATE_RUNNING   = 1,
+} stall_state_t;
+
+static stall_state_t volatile s_stall_state = STALL_STATE_IDLE;
+static int32_t volatile s_count_of_nested_calls[portNUM_PROCESSORS] = { 0 };
+static BaseType_t s_stored_interrupt_level;
+static uint32_t volatile esp_ipc_isr_finish_cmd;
+
+
+/**
+ * @brief Type of calling
+ */
+typedef enum {
+    IPC_ISR_WAIT_FOR_START = 0,   /*!< The caller is waiting for the start */
+    IPC_ISR_WAIT_FOR_END   = 1,   /*!< The caller is waiting for the end */
+} esp_ipc_isr_wait_t;
+
+#define IPC_ISR_ENTER_CRITICAL() portENTER_CRITICAL_SAFE(&s_ipc_isr_mux)
+#define IPC_ISR_EXIT_CRITICAL()  portEXIT_CRITICAL_SAFE(&s_ipc_isr_mux)
+
+static void esp_ipc_isr_call_and_wait(esp_ipc_isr_func_t func, void* arg, esp_ipc_isr_wait_t wait_for);
+
+
+/* Initializing IPC_ISR */
+
+static void esp_ipc_isr_init_cpu(void* arg)
+{
+    (void) arg;
+    const uint32_t cpuid = xPortGetCoreID();
+    uint32_t intr_source = ETS_FROM_CPU_INTR2_SOURCE + cpuid; // ETS_FROM_CPU_INTR2_SOURCE and ETS_FROM_CPU_INTR3_SOURCE
+    ESP_INTR_DISABLE(ETS_IPC_ISR_INUM);
+    intr_matrix_set(cpuid, intr_source, ETS_IPC_ISR_INUM);
+    ESP_INTR_ENABLE(ETS_IPC_ISR_INUM);
+
+    /* If this fails then the minimum stack size for this config is too close to running out */
+    assert(uxTaskGetStackHighWaterMark(NULL) > 128);
+
+    if (cpuid != 0) {
+        s_stall_state = STALL_STATE_RUNNING;
+    }
+    vTaskDelete(NULL);
+}
+
+void esp_ipc_isr_init(void)
+{
+    for (unsigned i = 0; i < portNUM_PROCESSORS; ++i) {
+        portBASE_TYPE res = xTaskCreatePinnedToCore(esp_ipc_isr_init_cpu, "ipc_isr_init", configMINIMAL_STACK_SIZE, NULL, 5, NULL, i);
+        assert(res == pdTRUE);
+        (void)res;
+    }
+}
+
+/* End initializing IPC_ISR */
+
+
+/* Public API functions */
+
+void IRAM_ATTR esp_ipc_isr_asm_call(esp_ipc_isr_func_t func, void* arg)
+{
+    IPC_ISR_ENTER_CRITICAL();
+    esp_ipc_isr_call_and_wait(func, arg, IPC_ISR_WAIT_FOR_START);
+    IPC_ISR_EXIT_CRITICAL();
+}
+
+void IRAM_ATTR esp_ipc_isr_asm_call_blocking(esp_ipc_isr_func_t func, void* arg)
+{
+    IPC_ISR_ENTER_CRITICAL();
+    esp_ipc_isr_call_and_wait(func, arg, IPC_ISR_WAIT_FOR_END);
+    IPC_ISR_EXIT_CRITICAL();
+}
+
+// This asm function is from esp_ipc_isr_routines.S.
+// It is waiting for the finish_cmd command in a loop.
+void esp_ipc_isr_waiting_for_finish_cmd(void* finish_cmd);
+
+/*
+ * esp_ipc_isr_stall_other_cpu is used for:
+ *  - stall other CPU,
+ *  - 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 wants 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.
+ */
+void IRAM_ATTR esp_ipc_isr_stall_other_cpu(void)
+{
+    if (s_stall_state == STALL_STATE_RUNNING) {
+        BaseType_t intLvl = portENTER_CRITICAL_NESTED();
+        const uint32_t cpu_id = xPortGetCoreID();
+        if (s_count_of_nested_calls[cpu_id]++ == 0) {
+            IPC_ISR_ENTER_CRITICAL();
+            s_stored_interrupt_level = intLvl;
+            esp_ipc_isr_finish_cmd = 0;
+            esp_ipc_isr_call_and_wait(&esp_ipc_isr_waiting_for_finish_cmd, (void*)&esp_ipc_isr_finish_cmd, IPC_ISR_WAIT_FOR_START);
+            return;
+        }
+
+        /* Interrupts are already disabled by the parent, we're nested here. */
+        portEXIT_CRITICAL_NESTED(intLvl);
+    }
+}
+
+void IRAM_ATTR esp_ipc_isr_release_other_cpu(void)
+{
+    if (s_stall_state == STALL_STATE_RUNNING) {
+        const uint32_t cpu_id = xPortGetCoreID();
+        if (--s_count_of_nested_calls[cpu_id] == 0) {
+            esp_ipc_isr_finish_cmd = 1;
+            IPC_ISR_EXIT_CRITICAL();
+            portEXIT_CRITICAL_NESTED(s_stored_interrupt_level);
+        } else if (s_count_of_nested_calls[cpu_id] < 0) {
+            assert(0);
+        }
+    }
+}
+
+void IRAM_ATTR esp_ipc_isr_stall_pause(void)
+{
+    IPC_ISR_ENTER_CRITICAL();
+    s_stall_state = STALL_STATE_IDLE;
+    IPC_ISR_EXIT_CRITICAL();
+}
+
+void IRAM_ATTR esp_ipc_isr_stall_abort(void)
+{
+    s_stall_state = STALL_STATE_IDLE;
+}
+
+void IRAM_ATTR esp_ipc_isr_stall_resume(void)
+{
+    IPC_ISR_ENTER_CRITICAL();
+    s_stall_state = STALL_STATE_RUNNING;
+    IPC_ISR_EXIT_CRITICAL();
+}
+
+void esp_dport_access_stall_other_cpu_start(void) __attribute__((alias("esp_ipc_isr_stall_other_cpu")));
+void esp_dport_access_stall_other_cpu_end(void) __attribute__((alias("esp_ipc_isr_release_other_cpu")));
+void esp_dport_access_int_pause(void) __attribute__((alias("esp_ipc_isr_stall_pause")));
+void esp_dport_access_int_abort(void) __attribute__((alias("esp_ipc_isr_stall_abort")));
+void esp_dport_access_int_resume(void) __attribute__((alias("esp_ipc_isr_stall_resume")));
+
+/* End public API functions */
+
+
+/* Private functions*/
+
+static void IRAM_ATTR esp_ipc_isr_call_and_wait(esp_ipc_isr_func_t func, void* arg, esp_ipc_isr_wait_t wait_for)
+{
+    const uint32_t cpu_id = xPortGetCoreID();
+
+    // waiting for the end of the previous call
+    while (!esp_ipc_isr_end_fl) {};
+
+    esp_ipc_func = func;
+    esp_ipc_func_arg = arg;
+
+    esp_ipc_isr_start_fl = 0;
+    esp_ipc_isr_end_fl = 0;
+
+    if (cpu_id == 0) {
+        // it runs an interrupt on cpu1
+        DPORT_REG_WRITE(SYSTEM_CPU_INTR_FROM_CPU_3_REG, SYSTEM_CPU_INTR_FROM_CPU_3);
+    } else {
+        // it runs an interrupt on cpu0
+        DPORT_REG_WRITE(SYSTEM_CPU_INTR_FROM_CPU_2_REG, SYSTEM_CPU_INTR_FROM_CPU_2);
+    }
+
+    // IPC_ISR handler will be called and `...isr_start` and `...isr_end` will be updated there
+
+    if (wait_for == IPC_ISR_WAIT_FOR_START) {
+        while (!esp_ipc_isr_start_fl) {};
+    } else {
+        // IPC_ISR_WAIT_FOR_END
+        while (!esp_ipc_isr_end_fl) {};
+    }
+}
+
+/* End private functions*/

components/esp_ipc/src/esp_ipc_isr/esp_ipc_isr_handler.S

@@ -0,0 +1,100 @@
+/*
+ * SPDX-FileCopyrightText: 2017-2021 Espressif Systems (Shanghai) CO LTD
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <xtensa/coreasm.h>
+#include <xtensa/corebits.h>
+#include <xtensa/config/system.h>
+#include "freertos/xtensa_context.h"
+#include "esp_private/panic_reason.h"
+#include "sdkconfig.h"
+#include "soc/soc.h"
+#include "soc/dport_reg.h"
+
+/* High-priority interrupt - IPC_ISR handler */
+
+#define L4_INTR_STACK_SIZE  16
+#define L4_INTR_A0_OFFSET   0
+#define L4_INTR_A2_OFFSET   4
+#define L4_INTR_A3_OFFSET   8
+#define L4_INTR_A4_OFFSET   12
+    .data
+_l4_intr_stack:
+    .space      L4_INTR_STACK_SIZE
+    .section .iram1,"ax"
+    .global     esp_ipc_isr_handler
+    .type       esp_ipc_isr_handler,@function
+    .align      4
+esp_ipc_isr_handler:
+    /* Allocate exception frame and save minimal context. */
+    /* Because the interrupt cause code has protection that only
+       allows one cpu to enter in the IPC_ISR section of the L4
+       interrupt at one time, there's no need to have two
+       _l4_intr_stack for each cpu */
+
+    /* Save A0, A2, A3, A4 so we can use those registers further*/
+    movi    a0, _l4_intr_stack
+    s32i    a2, a0, L4_INTR_A2_OFFSET
+    s32i    a3, a0, L4_INTR_A3_OFFSET
+    s32i    a4, a0, L4_INTR_A4_OFFSET
+    rsr     a2, EXCSAVE_4
+    s32i    a2, a0, L4_INTR_A0_OFFSET
+
+    /* disable nested iterrupts */
+    /* PS.EXCM is changed from 1 to 0 . It allows using usually exception handler instead of the Double exception handler. */
+    /* PS_UM = 1 */
+    movi    a0, PS_INTLEVEL(5) | PS_UM
+    wsr     a0, PS
+    rsync
+    /* restore PS will be done by rfi the end */
+
+    /*
+    * Reset isr interrupt flags
+    */
+    /* This int is edge-triggered and needs clearing. */
+    movi    a3, (1 << ETS_IPC_ISR_INUM)
+    wsr     a3, INTCLEAR
+
+    /* get CORE_ID */
+    getcoreid   a3
+    beqz    a3, 1f
+
+    /* current cpu is 1 */
+    movi    a3, SYSTEM_CPU_INTR_FROM_CPU_3_REG
+    movi    a4, 0
+    s32i    a4, a3, 0   /* clear intr */
+    j       2f
+1:
+    /* current cpu is 0 */
+    movi    a3, SYSTEM_CPU_INTR_FROM_CPU_2_REG
+    movi    a4, 0
+    s32i    a4, a3, 0   /* clear intr */
+2:
+
+    /* set the start flag */
+    movi    a0, esp_ipc_isr_start_fl
+    s32i    a0, a0, 0
+
+    /* Call the esp_ipc_function(void* arg) */
+    movi    a0, esp_ipc_func
+    l32i    a0, a0, 0
+    movi    a2, esp_ipc_func_arg
+    l32i    a2, a2, 0
+    callx0  a0
+
+    /* Done. Restore registers and return. */
+    movi    a0, _l4_intr_stack
+    l32i    a2, a0, L4_INTR_A2_OFFSET
+    l32i    a3, a0, L4_INTR_A3_OFFSET
+    l32i    a4, a0, L4_INTR_A4_OFFSET
+
+    /* set the end flag */
+    movi    a0, esp_ipc_isr_end_fl
+    s32i    a0, a0, 0
+
+    /* restore a0 */
+    rsr     a0, EXCSAVE_4
+    /* restores PS from EPS[4] and jumps to the address in EPC[4] */
+    rfi     4

components/esp_ipc/src/esp_ipc_isr/esp_ipc_isr_routines.S

@@ -0,0 +1,28 @@
+/*
+ * SPDX-FileCopyrightText: 2017-2021 Espressif Systems (Shanghai) CO LTD
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <xtensa/coreasm.h>
+#include <xtensa/corebits.h>
+#include <xtensa/config/system.h>
+#include <xtensa/hal.h>
+
+/* esp_ipc_isr_waiting_for_finish_cmd(void* finish_cmd)
+ *
+ * It should be called by the CALLX0 command from the handler of High-priority interrupt (4 lvl).
+ * Only these registers [a2, a3, a4] can be used here.
+ */
+    .section    .iram1, "ax"
+    .align      4
+    .global     esp_ipc_isr_waiting_for_finish_cmd
+    .type       esp_ipc_isr_waiting_for_finish_cmd, @function
+// Args:
+// a2 - finish_cmd (pointer on esp_ipc_isr_finish_cmd)
+esp_ipc_isr_waiting_for_finish_cmd:
+    /* waiting for the finish command */
+.check_finish_cmd:
+    l32i    a3, a2, 0
+    beqz    a3, .check_finish_cmd
+    ret

components/esp_ipc/test/CMakeLists.txt

@@ -1,4 +1,4 @@
-if(IDF_TARGET STREQUAL "esp32")
+if(IDF_TARGET STREQUAL "esp32" OR IDF_TARGET STREQUAL "esp32s3")
     idf_component_register(SRC_DIRS "."
                     PRIV_INCLUDE_DIRS "."
                     PRIV_REQUIRES cmock test_utils esp_ipc)

components/esp_ipc/test/component.mk

@@ -1 +1,2 @@
+COMPONENT_SRCDIRS := .
 COMPONENT_ADD_LDFLAGS = -Wl,--whole-archive -l$(COMPONENT_NAME) -Wl,--no-whole-archive

components/esp_ipc/test/test_ipc_isr.S

@@ -0,0 +1,61 @@
+/*
+ * SPDX-FileCopyrightText: 2015-2021 Espressif Systems (Shanghai) CO LTD
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <xtensa/coreasm.h>
+#include <xtensa/corebits.h>
+#include <xtensa/config/system.h>
+#include <xtensa/hal.h>
+
+/* esp_test_ipc_isr_asm(void *arg)
+ *
+ * It should be called by the CALLX0 command from the handler of High-priority interrupt (4 lvl).
+ * Only these registers [a2, a3, a4] can be used here.
+ */
+    .section    .iram1, "ax"
+    .align      4
+    .global     esp_test_ipc_isr_asm
+    .type       esp_test_ipc_isr_asm, @function
+// Args:
+// a2 - void* arg
+esp_test_ipc_isr_asm:
+    movi    a3, 0xa5a5
+    s32i    a3, a2, 0
+    ret
+
+
+/* esp_test_ipc_isr_get_other_core_id(void *arg)
+ *
+ * this function puts the core_id of the other CPU in the arg.
+ * use only a2, a3 and a4 regs here.
+*/
+    .section    .iram1, "ax"
+    .align      4
+    .global     esp_test_ipc_isr_get_other_core_id
+    .type       esp_test_ipc_isr_get_other_core_id, @function
+    // Args:
+    // a2 - void* arg
+    esp_test_ipc_isr_get_other_core_id:
+    rsr.prid a3
+    extui   a3, a3, 13, 1
+    s32i    a3, a2, 0
+    ret
+
+
+/* esp_test_ipc_isr_get_cycle_count_other_cpu(void *arg)
+ *
+ * this function puts CCOUNT of the other CPU in the arg.
+ * use only a2, a3 and a4 regs here.
+*/
+    .section    .iram1, "ax"
+    .align      4
+    .global     esp_test_ipc_isr_get_cycle_count_other_cpu
+    .type       esp_test_ipc_isr_get_cycle_count_other_cpu, @function
+    // Args:
+    // a2 - void* arg
+    esp_test_ipc_isr_get_cycle_count_other_cpu:
+    rsr.ccount a3
+    s32i    a3, a2, 0
+    ret

components/esp_ipc/test/test_ipc_isr.c

@@ -0,0 +1,85 @@
+#include <stdio.h>
+#include "sdkconfig.h"
+#include "freertos/FreeRTOS.h"
+#include "freertos/task.h"
+#include "freertos/semphr.h"
+#include "unity.h"
+#include "test_utils.h"
+#include "esp_rom_sys.h"
+#include "esp_ipc_isr.h"
+
+#ifdef CONFIG_ESP_IPC_ISR_ENABLE
+
+void esp_test_ipc_isr_asm(void* arg);
+
+TEST_CASE("Test ipc_isr blocking IPC function calls a ASM function", "[ipc]")
+{
+    int val = 0x5a5a;
+    esp_ipc_isr_asm_call_blocking(esp_test_ipc_isr_asm, &val);
+    TEST_ASSERT_EQUAL_HEX(val, 0xa5a5);
+}
+
+void esp_test_ipc_isr_get_other_core_id(void* arg);
+
+
+TEST_CASE("Test ipc_isr blocking IPC function calls get_other_core_id", "[ipc]")
+{
+    int val = 0x5a5a;
+    esp_ipc_isr_asm_call_blocking(esp_test_ipc_isr_get_other_core_id, &val);
+    TEST_ASSERT_EQUAL_HEX(val, 1);
+}
+
+TEST_CASE("Test ipc_isr exception in asm func leads to StoreProhibited not to Unhandled debug exception", "[ipc][reset=StoreProhibited,SW_CPU_RESET]")
+{
+    esp_ipc_isr_asm_call_blocking(esp_test_ipc_isr_asm, NULL);
+}
+
+void esp_test_ipc_isr_get_cycle_count_other_cpu(void* arg);
+
+TEST_CASE("Test ipc_isr blocking IPC function calls get_cycle_count_other_cpu", "[ipc]")
+{
+    int val = 0x5a5a;
+    esp_ipc_isr_asm_call_blocking(esp_test_ipc_isr_get_cycle_count_other_cpu, &val);
+    esp_rom_printf("CCOUNT CPU0 = %d\n", cpu_ll_get_cycle_count());
+    esp_rom_printf("CCOUNT CPU1 = %d\n", val);
+}
+
+static bool volatile s_stop;
+
+static void task_asm(void *arg)
+{
+    xSemaphoreHandle *sema = (xSemaphoreHandle *) arg;
+    int val;
+    int counter = 0;
+    printf("task_asm\n");
+    while (s_stop == false) {
+        val = 0x5a5a;
+        esp_ipc_isr_asm_call_blocking(esp_test_ipc_isr_asm, &val);
+        TEST_ASSERT_EQUAL_HEX(val, 0xa5a5);
+        ++counter;
+    }
+    printf("task_asm counter = %d\n", counter);
+    TEST_ASSERT_GREATER_THAN(1000000, counter);
+    xSemaphoreGive(*sema);
+    vTaskDelete(NULL);
+}
+
+TEST_CASE("Test ipc_isr two tasks use IPC function calls", "[ipc]")
+{
+    xSemaphoreHandle exit_sema[2];
+    exit_sema[0] = xSemaphoreCreateBinary();
+    exit_sema[1] = xSemaphoreCreateBinary();
+    s_stop = false;
+    printf("Test start\n");
+    xTaskCreatePinnedToCore(task_asm, "task_asm", 2048, &exit_sema[0], UNITY_FREERTOS_PRIORITY - 1, NULL, 0);
+    xTaskCreatePinnedToCore(task_asm, "task_asm", 2048, &exit_sema[1], UNITY_FREERTOS_PRIORITY - 1, NULL, 1);
+    vTaskDelay(5000 / portTICK_PERIOD_MS);
+    s_stop = true;
+    xSemaphoreTake(exit_sema[0], portMAX_DELAY);
+    xSemaphoreTake(exit_sema[1], portMAX_DELAY);
+    printf("Test end\n");
+
+    vSemaphoreDelete(exit_sema[0]);
+    vSemaphoreDelete(exit_sema[1]);
+}
+#endif /* CONFIG_ESP_IPC_ISR_ENABLE */

components/esp_system/CMakeLists.txt

@@ -38,7 +38,7 @@ else()
                                     # should be removable once using component init functions
                                     # link-time registration is used.
                                     esp_pm app_update nvs_flash pthread app_trace esp_gdbstub
-                                    espcoredump esp_phy efuse
+                                    espcoredump esp_phy efuse esp_ipc
                         LDFRAGMENTS "linker.lf" "app.lf")
     add_subdirectory(port)
 

components/esp_system/Kconfig

@@ -389,31 +389,6 @@ menu "ESP System Settings"
             If this option is enabled, the Task Wtachdog Timer will wach the CPU1
             Idle Task.
 
-    config ESP_IPC_TASK_STACK_SIZE
-        int "Inter-Processor Call (IPC) task stack size"
-        range 512 65536 if !APPTRACE_ENABLE
-        range 2048 65536 if APPTRACE_ENABLE
-        default 2048 if APPTRACE_ENABLE
-        default 1024
-        help
-            Configure the IPC tasks stack size. One IPC task runs on each core
-            (in dual core mode), and allows for cross-core function calls.
-
-            See IPC documentation for more details.
-
-            The default stack size should be enough for most common use cases.
-            It can be shrunk if you are sure that you do not use any custom
-            IPC functionality.
-
-    config ESP_IPC_USES_CALLERS_PRIORITY
-        bool "IPC runs at caller's priority"
-        default y
-        depends on !FREERTOS_UNICORE
-        help
-            If this option is not enabled then the IPC task will keep behavior
-            same as prior to that of ESP-IDF v4.0, and hence IPC task will run
-            at (configMAX_PRIORITIES - 1) priority.
-
     config ESP_PANIC_HANDLER_IRAM
         bool "Place panic handler code in IRAM"
         default n

components/esp_system/port/panic_handler.c

@@ -14,7 +14,7 @@
 #include <stdlib.h>
 
 #include "esp_spi_flash.h"
-
+#include "esp_ipc_isr.h"
 #include "esp_private/system_internal.h"
 
 #include "soc/soc_memory_layout.h"
@@ -165,9 +165,7 @@ static void panic_handler(void *frame, bool pseudo_excause)
     SOC_HAL_STALL_OTHER_CORES();
 #endif
 
-#if CONFIG_IDF_TARGET_ESP32
+    esp_ipc_isr_stall_abort();
-    esp_dport_access_int_abort();
-#endif
 
     if (esp_cpu_in_ocd_debug_mode()) {
 #if __XTENSA__
@@ -205,9 +203,7 @@ static void IRAM_ATTR panic_enable_cache(void) {
     int core_id = cpu_hal_get_core_id();
 
     if (!spi_flash_cache_enabled()) {
-#ifdef CONFIG_IDF_TARGET_ESP32
+        esp_ipc_isr_stall_abort();
-        esp_dport_access_int_abort();
-#endif
         spi_flash_enable_cache(core_id);
     }
 }

components/esp_system/port/soc/esp32/CMakeLists.txt

@@ -1,4 +1,4 @@
-set(srcs "dport_panic_highint_hdl.S"
+set(srcs "highint_hdl.S"
          "clk.c"
          "reset_reason.c"
          "system_internal.c"
@@ -15,7 +15,7 @@ add_prefix(srcs "${CMAKE_CURRENT_LIST_DIR}/" ${srcs})
 
 target_sources(${COMPONENT_LIB} PRIVATE ${srcs})
 
-#ld_include_panic_highint_hdl is added as an undefined symbol because otherwise the
+#ld_include_highint_hdl is added as an undefined symbol because otherwise the
 #linker will ignore panic_highint_hdl.S as it has no other files depending on any
 #symbols in it.
-set_property(TARGET ${COMPONENT_LIB} APPEND PROPERTY INTERFACE_LINK_LIBRARIES "-u ld_include_panic_highint_hdl")
+set_property(TARGET ${COMPONENT_LIB} APPEND PROPERTY INTERFACE_LINK_LIBRARIES "-u ld_include_highint_hdl")

components/esp_system/port/soc/esp32/highint_hdl.S

@@ -27,7 +27,7 @@
 /*
 
 Interrupt , a high-priority interrupt, is used for several things:
-- Dport access mediation
+- IPC_ISR handler
 - Cache error panic handler
 - Interrupt watchdog panic handler
 
@@ -64,11 +64,11 @@ _l4_intr_livelock_pro:
 xt_highint4:
 
 #ifndef CONFIG_FREERTOS_UNICORE
-    /* See if we're here for the dport access interrupt */
+    /* See if we're here for the IPC_ISR interrupt */
     rsr     a0, INTERRUPT
-    extui   a0, a0, ETS_DPORT_INUM, 1
+    extui   a0, a0, ETS_IPC_ISR_INUM, 1
-    bnez    a0, .handle_dport_access_int
+    bnez    a0, esp_ipc_isr_handler
-#endif // CONFIG_FREERTOS_UNICORE
+#endif // not CONFIG_FREERTOS_UNICORE
 
 #if CONFIG_ESP32_ECO3_CACHE_LOCK_FIX && CONFIG_ESP_INT_WDT
     /* See if we're here for the tg1 watchdog interrupt */
@@ -382,7 +382,7 @@ xt_highint4:
     /* Feed watchdog */
 8:  wdt_feed    TIMERG1
 
-9:  wsr     a0, PS                          /* restore iterrupt level */
+9:  wsr     a0, PS                          /* restore interrupt level */
 
     movi    a0, 0
     beqz    a5, 1f
@@ -415,75 +415,9 @@ xt_highint4:
 
 #endif
 
-
-#ifndef CONFIG_FREERTOS_UNICORE
-
-    .align      4
-.handle_dport_access_int:
-    /* This section is for dport access register protection */
-    /* Allocate exception frame and save minimal context. */
-    /* Because the interrupt cause code has protection that only
-       allows one cpu to enter in the dport section of the L4
-       interrupt at one time, there's no need to have two
-       _l4_intr_stack for each cpu */
-
-    /* This int is edge-triggered and needs clearing. */
-    movi    a0, (1<<ETS_DPORT_INUM)
-    wsr     a0, INTCLEAR
-
-    /* Save A2, A3, A4 so we can use those registers */
-    movi    a0, _l4_intr_stack
-    s32i    a2, a0, L4_INTR_A2_OFFSET
-    s32i    a3, a0, L4_INTR_A3_OFFSET
-    s32i    a4, a0, L4_INTR_A4_OFFSET
-
-    /* handle dport interrupt */
-    /* get CORE_ID */
-    getcoreid   a0
-    beqz    a0, 2f
-
-    /* current cpu is 1 */
-    movi    a0, DPORT_CPU_INTR_FROM_CPU_3_REG
-    movi    a2, 0
-    s32i    a2, a0, 0   /* clear intr */
-    movi    a0, 0       /* other cpu id */
-    j       3f
-2:
-    /* current cpu is 0 */
-    movi    a0, DPORT_CPU_INTR_FROM_CPU_2_REG
-    movi    a2, 0
-    s32i    a2, a0, 0   /* clear intr */
-    movi    a0, 1       /* other cpu id */
-3:
-    rsil    a4, CONFIG_ESP32_DPORT_DIS_INTERRUPT_LVL /* disable nested iterrupt */
-    /* set and wait flag */
-    movi    a2, dport_access_start
-    addx4   a2, a0, a2
-    movi    a3, 1
-    s32i    a3, a2, 0
-    memw
-    movi    a2, dport_access_end
-    addx4   a2, a0, a2
-.check_dport_access_end:
-    l32i    a3, a2, 0
-    beqz    a3, .check_dport_access_end
-
-    wsr     a4, PS                                   /* restore iterrupt level */
-    /* Done. Restore registers and return. */
-    movi    a0, _l4_intr_stack
-    l32i    a2, a0, L4_INTR_A2_OFFSET
-    l32i    a3, a0, L4_INTR_A3_OFFSET
-    l32i    a4, a0, L4_INTR_A4_OFFSET
-    rsync                                   /* ensure register restored */
-
-    rsr     a0, EXCSAVE_4                   /* restore a0 */
-    rfi     4
-
-#endif // CONFIG_FREERTOS_UNICORE
-
 /* The linker has no reason to link in this file; all symbols it exports are already defined
    (weakly!) in the default int handler. Define a symbol here so we can use it to have the
    linker inspect this anyway. */
 
-    .global ld_include_panic_highint_hdl
+    .global ld_include_highint_hdl
-ld_include_panic_highint_hdl:
+ld_include_highint_hdl:

components/esp_system/port/soc/esp32/system_internal.c

@@ -18,6 +18,7 @@
 #include "esp_attr.h"
 #include "esp_efuse.h"
 #include "esp_log.h"
+#include "esp_ipc_isr.h"
 #include "sdkconfig.h"
 #include "esp_rom_uart.h"
 #include "soc/dport_reg.h"
@@ -67,7 +68,7 @@ void IRAM_ATTR esp_restart_noos(void)
     esp_cpu_stall(other_core_id);
 
     // Other core is now stalled, can access DPORT registers directly
-    esp_dport_access_int_abort();
+    esp_ipc_isr_stall_abort();
 
     //Todo: Refactor to use Interrupt or Task Watchdog API, and a system level WDT context
     // Disable TG0/TG1 watchdogs

components/esp_system/port/soc/esp32s2/CMakeLists.txt

@@ -1,4 +1,4 @@
-set(srcs "dport_panic_highint_hdl.S"
+set(srcs "highint_hdl.S"
          "clk.c"
          "reset_reason.c"
          "system_internal.c"
@@ -18,7 +18,7 @@ if(CONFIG_ESP_CONSOLE_USB_CDC)
     target_sources(${COMPONENT_LIB} PRIVATE "${CMAKE_CURRENT_LIST_DIR}/usb_console.c")
 endif()
 
-#ld_include_panic_highint_hdl is added as an undefined symbol because otherwise the
+#ld_include_highint_hdl is added as an undefined symbol because otherwise the
-#linker will ignore panic_highint_hdl.S as it has no other files depending on any
+#linker will ignore highint_hdl.S as it has no other files depending on any
 #symbols in it.
-set_property(TARGET ${COMPONENT_LIB} APPEND PROPERTY INTERFACE_LINK_LIBRARIES "-u ld_include_panic_highint_hdl")
+set_property(TARGET ${COMPONENT_LIB} APPEND PROPERTY INTERFACE_LINK_LIBRARIES "-u ld_include_highint_hdl")

components/esp_system/port/soc/esp32s2/highint_hdl.S

@@ -106,5 +106,5 @@ xt_highint4:
    (weakly!) in the default int handler. Define a symbol here so we can use it to have the
    linker inspect this anyway. */
 
-    .global ld_include_panic_highint_hdl
+    .global ld_include_highint_hdl
-ld_include_panic_highint_hdl:
+ld_include_highint_hdl:

components/esp_system/port/soc/esp32s3/CMakeLists.txt

@@ -1,4 +1,4 @@
-set(srcs "dport_panic_highint_hdl.S"
+set(srcs "highint_hdl.S"
          "clk.c"
          "reset_reason.c"
          "system_internal.c"
@@ -18,7 +18,7 @@ if(CONFIG_ESP_CONSOLE_USB_CDC)
     target_sources(${COMPONENT_LIB} PRIVATE "${CMAKE_CURRENT_LIST_DIR}/usb_console.c")
 endif()
 
-#ld_include_panic_highint_hdl is added as an undefined symbol because otherwise the
+#ld_include_highint_hdl is added as an undefined symbol because otherwise the
 #linker will ignore panic_highint_hdl.S as it has no other files depending on any
 #symbols in it.
-set_property(TARGET ${COMPONENT_LIB} APPEND PROPERTY INTERFACE_LINK_LIBRARIES "-u ld_include_panic_highint_hdl")
+set_property(TARGET ${COMPONENT_LIB} APPEND PROPERTY INTERFACE_LINK_LIBRARIES "-u ld_include_highint_hdl")

components/esp_system/port/soc/esp32s3/highint_hdl.S

@@ -26,6 +26,7 @@
 /*
 
 Interrupt , a high-priority interrupt, is used for several things:
+- IPC_ISR handler
 - Cache error panic handler
 - Interrupt watchdog panic handler
 
@@ -44,6 +45,13 @@ _l4_intr_stack:
     .align      4
 xt_highint4:
 
+#ifndef CONFIG_FREERTOS_UNICORE
+    /* See if we're here for the IPC_ISR interrupt */
+    rsr     a0, INTERRUPT
+    extui   a0, a0, ETS_IPC_ISR_INUM, 1
+    bnez    a0, esp_ipc_isr_handler
+#endif // not CONFIG_FREERTOS_UNICORE
+
     /* Allocate exception frame and save minimal context. */
     mov     a0, sp
     addi    sp, sp, -XT_STK_FRMSZ
@@ -126,5 +134,5 @@ xt_highint4:
    (weakly!) in the default int handler. Define a symbol here so we can use it to have the
    linker inspect this anyway. */
 
-    .global ld_include_panic_highint_hdl
+    .global ld_include_highint_hdl
-ld_include_panic_highint_hdl:
+ld_include_highint_hdl:

components/freertos/port/port_common.c

@@ -77,12 +77,6 @@ void esp_startup_start_app_common(void)
 
 	esp_crosscore_int_init();
 
-#ifndef CONFIG_FREERTOS_UNICORE
-#if CONFIG_IDF_TARGET_ESP32
-	esp_dport_access_int_init();
-#endif
-#endif
-
 #ifdef CONFIG_ESP_SYSTEM_GDBSTUB_RUNTIME
     esp_gdbstub_init();
 #endif // CONFIG_ESP_SYSTEM_GDBSTUB_RUNTIME

components/freertos/port/xtensa/port.c

@@ -518,9 +518,6 @@ void esp_startup_start_app_other_cores(void)
 #endif
 
 	esp_crosscore_int_init();
-#if CONFIG_IDF_TARGET_ESP32
-	esp_dport_access_int_init();
-#endif
 
 	ESP_EARLY_LOGI(TAG, "Starting scheduler on APP CPU.");
 	xPortStartScheduler();

components/soc/esp32/include/soc/dport_reg.h

@@ -1156,6 +1156,8 @@
 #define DPORT_CPU_INTR_FROM_CPU_1_V  0x1
 #define DPORT_CPU_INTR_FROM_CPU_1_S  0
 
+#define SYSTEM_CPU_INTR_FROM_CPU_2_REG          DPORT_CPU_INTR_FROM_CPU_2_REG
+#define SYSTEM_CPU_INTR_FROM_CPU_2              DPORT_CPU_INTR_FROM_CPU_2
 #define DPORT_CPU_INTR_FROM_CPU_2_REG          (DR_REG_DPORT_BASE + 0x0E4)
 /* DPORT_CPU_INTR_FROM_CPU_2 : R/W ;bitpos:[0] ;default: 1'b0 ; */
 /*description: */
@@ -1164,6 +1166,8 @@
 #define DPORT_CPU_INTR_FROM_CPU_2_V  0x1
 #define DPORT_CPU_INTR_FROM_CPU_2_S  0
 
+#define SYSTEM_CPU_INTR_FROM_CPU_3_REG          DPORT_CPU_INTR_FROM_CPU_3_REG
+#define SYSTEM_CPU_INTR_FROM_CPU_3              DPORT_CPU_INTR_FROM_CPU_3
 #define DPORT_CPU_INTR_FROM_CPU_3_REG          (DR_REG_DPORT_BASE + 0x0E8)
 /* DPORT_CPU_INTR_FROM_CPU_3 : R/W ;bitpos:[0] ;default: 1'b0 ; */
 /*description: */

components/soc/esp32/include/soc/soc.h

@@ -307,8 +307,8 @@
 #define ETS_GPIO_NMI_SOURCE                     23/**< interrupt of GPIO, NMI*/
 #define ETS_FROM_CPU_INTR0_SOURCE               24/**< interrupt0 generated from a CPU, level*/ /* Used for FreeRTOS */
 #define ETS_FROM_CPU_INTR1_SOURCE               25/**< interrupt1 generated from a CPU, level*/ /* Used for FreeRTOS */
-#define ETS_FROM_CPU_INTR2_SOURCE               26/**< interrupt2 generated from a CPU, level*/ /* Used for DPORT Access */
+#define ETS_FROM_CPU_INTR2_SOURCE               26/**< interrupt2 generated from a CPU, level*/ /* Used for IPC_ISR */
-#define ETS_FROM_CPU_INTR3_SOURCE               27/**< interrupt3 generated from a CPU, level*/ /* Used for DPORT Access */
+#define ETS_FROM_CPU_INTR3_SOURCE               27/**< interrupt3 generated from a CPU, level*/ /* Used for IPC_ISR */
 #define ETS_SPI0_INTR_SOURCE                    28/**< interrupt of SPI0, level, SPI0 is for Cache Access, do not use this*/
 #define ETS_SPI1_INTR_SOURCE                    29/**< interrupt of SPI1, level, SPI1 is for flash read/write, do not use this*/
 #define ETS_SPI2_INTR_SOURCE                    30/**< interrupt of SPI2, level*/
@@ -382,7 +382,7 @@
  *      25                      4               extern level            CACHEERR
  *      26                      5               extern level
  *      27                      3               extern level            Reserved                Reserved
- *      28                      4               extern edge             DPORT ACCESS            DPORT ACCESS
+ *      28                      4               extern edge             IPC_ISR                 IPC_ISR
  *      29                      3               software                Reserved                Reserved
  *      30                      4               extern edge             Reserved                Reserved
  *      31                      5               extern level
@@ -399,7 +399,7 @@
 #define ETS_MEMACCESS_ERR_INUM                  25
 /* backwards compatibility only, use ETS_MEMACCESS_ERR_INUM instead*/
 #define ETS_CACHEERR_INUM                       ETS_MEMACCESS_ERR_INUM
-#define ETS_DPORT_INUM                          28
+#define ETS_IPC_ISR_INUM                        28
 
 //CPU0 Interrupt number used in ROM, should be cancelled in SDK
 #define ETS_SLC_INUM                            1

components/soc/esp32c3/include/soc/periph_defs.h

@@ -102,8 +102,8 @@ typedef enum {
     ETS_SHA_INTR_SOURCE,                        /**< interrupt of SHA accelerator, level*/
     ETS_FROM_CPU_INTR0_SOURCE,                  /**< interrupt0 generated from a CPU, level*/ /* Used for FreeRTOS */
     ETS_FROM_CPU_INTR1_SOURCE,                  /**< interrupt1 generated from a CPU, level*/ /* Used for FreeRTOS */
-    ETS_FROM_CPU_INTR2_SOURCE,                  /**< interrupt2 generated from a CPU, level*/ /* Used for DPORT Access */
+    ETS_FROM_CPU_INTR2_SOURCE,                  /**< interrupt2 generated from a CPU, level*/
-    ETS_FROM_CPU_INTR3_SOURCE,                  /**< interrupt3 generated from a CPU, level*/ /* Used for DPORT Access */
+    ETS_FROM_CPU_INTR3_SOURCE,                  /**< interrupt3 generated from a CPU, level*/
     ETS_ASSIST_DEBUG_INTR_SOURCE,               /**< interrupt of Assist debug module, LEVEL*/
     ETS_DMA_APBPERI_PMS_INTR_SOURCE,
     ETS_CORE0_IRAM0_PMS_INTR_SOURCE,

components/soc/esp32c3/include/soc/soc.h

@@ -317,7 +317,6 @@
 #define ETS_T1_WDT_INUM                         24
 #define ETS_CACHEERR_INUM                       25
 #define ETS_MEMPROT_ERR_INUM                    26
-#define ETS_DPORT_INUM                          28
 
 //CPU0 Max valid interrupt number
 #define ETS_MAX_INUM                            31

components/soc/esp32h2/include/soc/periph_defs.h

@@ -102,8 +102,8 @@ typedef enum {
     ETS_SHA_INTR_SOURCE,                        /**< interrupt of SHA accelerator, level*/
     ETS_FROM_CPU_INTR0_SOURCE,                  /**< interrupt0 generated from a CPU, level*/ /* Used for FreeRTOS */
     ETS_FROM_CPU_INTR1_SOURCE,                  /**< interrupt1 generated from a CPU, level*/ /* Used for FreeRTOS */
-    ETS_FROM_CPU_INTR2_SOURCE,                  /**< interrupt2 generated from a CPU, level*/ /* Used for DPORT Access */
+    ETS_FROM_CPU_INTR2_SOURCE,                  /**< interrupt2 generated from a CPU, level*/
-    ETS_FROM_CPU_INTR3_SOURCE,                  /**< interrupt3 generated from a CPU, level*/ /* Used for DPORT Access */
+    ETS_FROM_CPU_INTR3_SOURCE,                  /**< interrupt3 generated from a CPU, level*/
     ETS_ASSIST_DEBUG_INTR_SOURCE,               /**< interrupt of Assist debug module, LEVEL*/
     ETS_DMA_APBPERI_PMS_INTR_SOURCE,
     ETS_CORE0_IRAM0_PMS_INTR_SOURCE,

components/soc/esp32h2/include/soc/soc.h

@@ -347,7 +347,6 @@
 #define ETS_T1_WDT_INUM                         24
 #define ETS_CACHEERR_INUM                       25
 #define ETS_MEMPROT_ERR_INUM                    26
-#define ETS_DPORT_INUM                          28
 
 //CPU0 Max valid interrupt number
 #define ETS_MAX_INUM                            31

components/soc/esp32s2/include/soc/periph_defs.h

@@ -86,8 +86,8 @@ typedef enum {
     ETS_DEDICATED_GPIO_INTR_SOURCE,             /**< interrupt of dedicated GPIO, level*/
     ETS_FROM_CPU_INTR0_SOURCE,                  /**< interrupt0 generated from a CPU, level*/ /* Used for FreeRTOS */
     ETS_FROM_CPU_INTR1_SOURCE,                  /**< interrupt1 generated from a CPU, level*/ /* Used for FreeRTOS */
-    ETS_FROM_CPU_INTR2_SOURCE,                  /**< interrupt2 generated from a CPU, level*/ /* Used for DPORT Access */
+    ETS_FROM_CPU_INTR2_SOURCE,                  /**< interrupt2 generated from a CPU, level*/
-    ETS_FROM_CPU_INTR3_SOURCE,                  /**< interrupt3 generated from a CPU, level*/ /* Used for DPORT Access */
+    ETS_FROM_CPU_INTR3_SOURCE,                  /**< interrupt3 generated from a CPU, level*/
 
     ETS_SPI1_INTR_SOURCE = 32,                  /**< interrupt of SPI1, level, SPI1 is for flash read/write, do not use this*/
     ETS_SPI2_INTR_SOURCE,                       /**< interrupt of SPI2, level*/

components/soc/esp32s2/include/soc/soc.h

@@ -299,23 +299,23 @@
 
 //interrupt cpu using table, Please see the core-isa.h
 /*************************************************************************************************************
- *      Intr num                Level           Type                    PRO CPU usage           APP CPU uasge
+ *      Intr num                Level           Type                    PRO CPU usage
- *      0                       1               extern level            WMAC                    Reserved
+ *      0                       1               extern level            WMAC
- *      1                       1               extern level            BT/BLE Host HCI DMA     BT/BLE Host HCI DMA
+ *      1                       1               extern level            BT/BLE Host HCI DMA
  *      2                       1               extern level
  *      3                       1               extern level
  *      4                       1               extern level            WBB
- *      5                       1               extern level            BT/BLE Controller       BT/BLE Controller
+ *      5                       1               extern level            BT/BLE Controller
- *      6                       1               timer                   FreeRTOS Tick(L1)       FreeRTOS Tick(L1)
+ *      6                       1               timer                   FreeRTOS Tick(L1)
- *      7                       1               software                BT/BLE VHCI             BT/BLE VHCI
+ *      7                       1               software                BT/BLE VHCI
- *      8                       1               extern level            BT/BLE BB(RX/TX)        BT/BLE BB(RX/TX)
+ *      8                       1               extern level            BT/BLE BB(RX/TX)
  *      9                       1               extern level
  *      10                      1               extern edge
  *      11                      3               profiling
  *      12                      1               extern level
  *      13                      1               extern level
- *      14                      7               nmi                     Reserved                Reserved
+ *      14                      7               nmi                     Reserved
- *      15                      3               timer                   FreeRTOS Tick(L3)       FreeRTOS Tick(L3)
+ *      15                      3               timer                   FreeRTOS Tick(L3)
  *      16                      5               timer
  *      17                      1               extern level
  *      18                      1               extern level
@@ -327,10 +327,10 @@
  *      24                      4               extern level            TG1_WDT
  *      25                      4               extern level            CACHEERR
  *      26                      5               extern level
- *      27                      3               extern level            Reserved                Reserved
+ *      27                      3               extern level            Reserved
- *      28                      4               extern edge             DPORT ACCESS            DPORT ACCESS
+ *      28                      4               extern edge             Reserved
- *      29                      3               software                Reserved                Reserved
+ *      29                      3               software                Reserved
- *      30                      4               extern edge             Reserved                Reserved
+ *      30                      4               extern edge             Reserved
  *      31                      5               extern level
  *************************************************************************************************************
  */
@@ -343,7 +343,6 @@
 #define ETS_FRC1_INUM                           22
 #define ETS_T1_WDT_INUM                         24
 #define ETS_MEMACCESS_ERR_INUM                  25
-#define ETS_DPORT_INUM                          28
 
 //CPU0 Interrupt number used in ROM, should be cancelled in SDK
 #define ETS_SLC_INUM                            1

components/soc/esp32s3/include/soc/periph_defs.h

@@ -139,8 +139,8 @@ typedef enum {
     ETS_SHA_INTR_SOURCE,                        /**< interrupt of SHA accelerator, level*/
     ETS_FROM_CPU_INTR0_SOURCE,                  /**< interrupt0 generated from a CPU, level*/ /* Used for FreeRTOS */
     ETS_FROM_CPU_INTR1_SOURCE,                  /**< interrupt1 generated from a CPU, level*/ /* Used for FreeRTOS */
-    ETS_FROM_CPU_INTR2_SOURCE,                  /**< interrupt2 generated from a CPU, level*/ /* Used for DPORT Access */
+    ETS_FROM_CPU_INTR2_SOURCE,                  /**< interrupt2 generated from a CPU, level*/ /* Used for IPC_ISR */
-    ETS_FROM_CPU_INTR3_SOURCE,                  /**< interrupt3 generated from a CPU, level*/ /* Used for DPORT Access */
+    ETS_FROM_CPU_INTR3_SOURCE,                  /**< interrupt3 generated from a CPU, level*/ /* Used for IPC_ISR */
     ETS_ASSIST_DEBUG_INTR_SOURCE,               /**< interrupt of Assist debug module, LEVEL*/
     ETS_DMA_APBPERI_PMS_INTR_SOURCE,
     ETS_CORE0_IRAM0_PMS_INTR_SOURCE,

components/soc/esp32s3/include/soc/soc.h

@@ -331,7 +331,7 @@
  *      25                      4               extern level            CACHEERR
  *      26                      5               extern level
  *      27                      3               extern level            Reserved                Reserved
- *      28                      4               extern edge             DPORT ACCESS            DPORT ACCESS
+ *      28                      4               extern edge             IPC_ISR                 IPC_ISR
  *      29                      3               software                Reserved                Reserved
  *      30                      4               extern edge             Reserved                Reserved
  *      31                      5               extern level
@@ -346,7 +346,7 @@
 #define ETS_FRC1_INUM                           22
 #define ETS_T1_WDT_INUM                         24
 #define ETS_CACHEERR_INUM                       25
-#define ETS_DPORT_INUM                          28
+#define ETS_IPC_ISR_INUM                        28
 
 //CPU0 Interrupt number used in ROM, should be cancelled in SDK
 #define ETS_SLC_INUM                            1

docs/en/api-guides/hlinterrupts.rst

@@ -31,7 +31,7 @@ Using these symbols is done by creating an assembly file (suffix .S) and definin
         rsr     a0, EXCSAVE_5
         rfi     5
 
-For a real-life example, see the :component_file:`esp_system/port/soc/{IDF_TARGET_PATH_NAME}/dport_panic_highint_hdl.S` file; the panic handler interrupt is implemented there.
+For a real-life example, see the :component_file:`esp_system/port/soc/{IDF_TARGET_PATH_NAME}/highint_hdl.S` file; the panic handler interrupt is implemented there.
 
 
 Notes

docs/en/api-reference/system/ipc.rst

@@ -35,9 +35,53 @@ mutex hence simultaneous IPC calls are not possible.
 Care should taken to avoid deadlock when writing functions to be executed by
 IPC, especially when attempting to take a mutex within the function.
 
+.. _hi_priority_ipc:
+
+Hi-priority IPC
+---------------
+
+In some cases, we need to quickly get the state of the other CPU (for example, in the core dump, in the GDB stub, in some unit tests, in the dport workaround, etc.), and usually it can be implemented as a fairly simple function and can be written in assembler. 
+For these purposes, the IPC API has special functions :cpp:func:`esp_ipc_isr_asm_call` and :cpp:func:`esp_ipc_isr_asm_call_blocking`. 
+The `esp_ipc_isr_asm...(asm_func, arg)` functions trigger the High-priority interrupt (4 level) on the other CPU. The given assembler function (asm_func) will run on the other CPU in the context of the interrupt. This assembler function will be called by the CALLX0 command therefore it must be written in assembler.
+
+:cpp:func:`esp_ipc_isr_asm_call` - triggers the Hi-priority interrupt on a particular core to execute a given function. The CPU which called this function will be blocked until the other CPU begins execution of the given function.
+
+:cpp:func:`esp_ipc_isr_asm_call_blocking` is similar but will block the calling CPU until the other CPU has completed the execution of the given function.
+
+:cpp:func:`esp_ipc_isr_stall_other_cpu` stalls the other CPU and the calling CPU disables interrupts with level 3 and lower. To finish stalling the other CPU call :cpp:func:`esp_ipc_isr_release_other_cpu`. The stalled CPU disables interrupts with level 5 and lower.
+
+Functions executed by Hi-priority IPC must be functions of type `void func(void *arg)`. Examples of a assembler function see in :idf_file:`components/esp_ipc/src/esp_ipc_isr/esp_ipc_isr_routines.S`, :idf_file:`components/esp_ipc/test/test_ipc_isr.S` and below. In the asm function, you can use only a few registers as they were saved in the interrupt handler before calling this function, their use is safe. The registers:`a2` as `void *arg`, a3 and a4 are free for use.
+
+Some feature:
+
+- The asm function should be placed in the IRAM memory and aligned on a memory address multiple of 4.
+- As the asm function is run in the context of the High-priority interrupt, a C function can no be called because the windows spill is disabled.
+- Use only a2, a3 and a4 registers in the asm function (to workaround it see esp_complex_asm_func).
+- A CPU, that called these APIs `esp_ipc_isr_asm...(asm_func, arg)`, disables interrupts with level 3 and lower.
+- A CPU, where the asm function is executed, disables interrupts with level 5 and lower.
+- You do not need to take care about handling of the Hi-priority interrupt.
+
+
+.. code-block:: asm
+
+    /* esp_test_ipc_isr_get_cycle_count_other_cpu(void *arg) */
+    // this function puts CCOUNT of the other CPU in the arg.
+    // use only a2, a3 and a4 regs here.
+    .section    .iram1, "ax"
+    .align      4
+    .global     esp_test_ipc_isr_get_cycle_count_other_cpu
+    .type       esp_test_ipc_isr_get_cycle_count_other_cpu, @function
+    // Args:
+    // a2 - void* arg
+    esp_test_ipc_isr_get_cycle_count_other_cpu:
+    rsr.ccount a3
+    s32i    a3, a2, 0
+    ret
+
+
+This number of registers available for use is sufficient for most simple cases. But if you need to run a more complex asm function, you can pass as an argument a pointer to a structure that can accept additional registers to a buffer to make them free to use. Remember to restore them before returning See the :example:`system/ipc/ipc_isr`.
+
 API Reference
 -------------
 
 .. include-build-file:: inc/esp_ipc.inc
-
-

examples/system/ipc/ipc_isr/CMakeLists.txt

@@ -0,0 +1,6 @@
+# The following lines of boilerplate have to be in your project's CMakeLists
+# in this exact order for cmake to work correctly
+cmake_minimum_required(VERSION 3.5)
+
+include($ENV{IDF_PATH}/tools/cmake/project.cmake)
+project(ipc_isr)

examples/system/ipc/ipc_isr/Makefile

@@ -0,0 +1,8 @@
+#
+# This is a project Makefile. It is assumed the directory this Makefile resides in is a
+# project subdirectory.
+#
+
+PROJECT_NAME := ipc_isr
+
+include $(IDF_PATH)/make/project.mk

examples/system/ipc/ipc_isr/README.md

@@ -0,0 +1,56 @@
+| Supported Targets | ESP32 | ESP32-S3 |
+| ----------------- | ----- | -------- |
+
+# Hi-priority IPC example
+
+This example demonstrates how to use Hi-priority IPC, it is based on Hi-priority interrupt (level 4). This feature can be useful in case when need quickly to get the state of the other CPU (consult the [Hi-priority IPC](https://docs.espressif.com/projects/esp-idf/en/latest/esp32/api-reference/system/ipc.html#hi-priority-ipc)).
+In the `asm_funcs.S` file are functions that will be run on the other core. The function should be fairly simple that can be written in assembler.
+
+The first asm function `get_ps_other_cpu()` demonstrates a simple way of usage, it returns the PS register of other core.
+
+The second asm function `extended_ipc_isr_asm()` demonstrates way when need to do some complex operations on other core, for this, save registers to the buffer (regs[]) making them available for use. Then using passed arguments (in[]) do some work and write the result to out[]. At the end recover saved registers.
+
+## How to use example
+
+### Hardware Required
+
+Example should be able to run on any commonly available ESP32 development board. The chip should have two cores.
+
+### Configure the project
+
+- `CONFIG_FREERTOS_UNICORE` - disabled,
+- `CONFIG_ESP_IPC_ISR_ENABLE` - enabled.
+
+```
+idf.py menuconfig
+```
+
+### Build and Flash
+
+```
+idf.py build flash monitor
+```
+
+(To exit the serial monitor, type ``Ctrl-]``.)
+
+See the [Getting Started Guide](https://docs.espressif.com/projects/esp-idf/en/latest/get-started/index.html) for full steps to configure and use ESP-IDF to build projects.
+
+
+## Example output
+
+```
+I (304) example: Start
+I (304) example: call get_ps_other_cpu
+I (314) example: PS_INTLEVEL = 0x5
+I (314) example: PS_EXCM = 0x0
+I (324) example: PS_UM = 0x1
+I (324) example: call extended_ipc_isr_asm
+I (324) example: in[0] = 0x1
+I (334) example: in[1] = 0x2
+I (334) example: in[2] = 0x3
+I (334) example: out[0] = (in[0] | in[1] | in[2]) = 0x3
+I (344) example: out[1] = (in[0] & in[1] & in[2]) = 0x6
+I (354) example: out[2] = in[2] = 0x3
+I (354) example: out[3] = PS of other cpu = 0x25
+I (364) example: End
+```

examples/system/ipc/ipc_isr/example_test.py

@@ -0,0 +1,28 @@
+from __future__ import unicode_literals
+
+import ttfw_idf
+
+
+@ttfw_idf.idf_example_test(env_tag='Example_GENERIC', target=['esp32'])
+def test_examples_ipc_isr(env, _):  # type: (ttfw_idf.TinyFW.Env, None) -> None
+
+    dut = env.get_dut('ipc_isr', 'examples/system/ipc/ipc_isr')
+    dut.start_app()
+
+    dut.expect_all('example: Start',
+                   'example: PS_INTLEVEL = 0x5',
+                   'example: PS_EXCM = 0x0',
+                   'example: PS_UM = 0x1',
+                   'example: in[0] = 0x1',
+                   'example: in[1] = 0x2',
+                   'example: in[2] = 0x3',
+                   'example: out[0] = (in[0] | in[1] | in[2]) = 0x3',
+                   'example: out[1] = (in[0] & in[1] & in[2]) = 0x6',
+                   'example: out[2] = in[2] = 0x3',
+                   'example: out[3] = PS of other cpu = 0x25',
+                   'example: End',
+                   timeout=10)
+
+
+if __name__ == '__main__':
+    test_examples_ipc_isr()

examples/system/ipc/ipc_isr/main/CMakeLists.txt

@@ -0,0 +1,3 @@
+idf_component_register(SRCS "main.c"
+                            "asm_funcs.S"
+                    INCLUDE_DIRS ".")

examples/system/ipc/ipc_isr/main/asm_funcs.S

@@ -0,0 +1,89 @@
+/*
+ * SPDX-FileCopyrightText: 2015-2021 Espressif Systems (Shanghai) CO LTD
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <xtensa/coreasm.h>
+#include <xtensa/corebits.h>
+#include <xtensa/config/system.h>
+#include <xtensa/hal.h>
+
+/* get_ps_other_cpu(void *arg)
+ *
+ * It should be called by the CALLX0 command from the handler of High-priority interrupt (4 lvl).
+ * Only these registers [a2, a3, a4] can be used here.
+ * Returns PS.
+ */
+    .section    .iram1, "ax"
+    .align      4
+    .global     get_ps_other_cpu
+    .type       get_ps_other_cpu, @function
+// Args:
+// a2 - void* arg
+get_ps_other_cpu:
+    rsr     a3, PS
+    s32i    a3, a2, 0
+    ret
+
+
+/* extended_ipc_isr_asm(void *arg)
+ *
+ * It should be called by the CALLX0 command from the handler of High-priority interrupt (4 lvl).
+ * Only these registers [a2, a3, a4] can be used here.
+ * This function receives a structure (arg) where can be saved some regs
+ * to get them available here, at the end of the function we recover the saved regs.
+ */
+    .section    .iram1, "ax"
+    .align      4
+    .global     extended_ipc_isr_asm
+    .type       extended_ipc_isr_asm, @function
+    // Args:
+    // a2 - arg_data_t* arg
+extended_ipc_isr_asm:
+
+    /* save all registers (a5-a15 -> regs[11]) */
+    s32i    a5,  a2, 0
+    s32i    a6,  a2, 4
+    s32i    a7,  a2, 8
+    s32i    a8,  a2, 12
+    s32i    a9,  a2, 16
+    s32i    a10, a2, 20
+    s32i    a11, a2, 24
+    s32i    a12, a2, 28
+    s32i    a13, a2, 32
+    s32i    a14, a2, 36
+    s32i    a15, a2, 40
+
+    /* do some work with a2 - a15 */
+    l32i    a5, a2, 44 /* a5 <- in[0] */
+    l32i    a6, a2, 48 /* a6 <- in[1] */
+    l32i    a7, a2, 52 /* a7 <- in[2] */
+
+    or      a8, a5, a6
+    or      a8, a8, a7
+
+    add     a9, a5, a6
+    add     a9, a9, a7
+
+    mov     a10, a7
+
+    rsr     a11, PS
+    s32i    a8,  a2, 56  /* a8 -> out[0] */
+    s32i    a9,  a2, 60  /* a9 -> out[1] */
+    s32i    a10, a2, 64 /* a10 -> out[2] */
+    s32i    a11, a2, 68 /* a11 -> out[3] */
+
+    /* restore all saved registers (regs[11] -> a5-a15) */
+    l32i    a5,  a2, 0
+    l32i    a6,  a2, 4
+    l32i    a7,  a2, 8
+    l32i    a8,  a2, 12
+    l32i    a9,  a2, 16
+    l32i    a10, a2, 20
+    l32i    a11, a2, 24
+    l32i    a12, a2, 28
+    l32i    a13, a2, 32
+    l32i    a14, a2, 36
+    l32i    a15, a2, 40
+    ret

examples/system/ipc/ipc_isr/main/component.mk

@@ -0,0 +1,4 @@
+#
+# "main" pseudo-component makefile.
+#
+# (Uses default behaviour of compiling all source files in directory, adding 'include' to include path.)

examples/system/ipc/ipc_isr/main/main.c

@@ -0,0 +1,61 @@
+/* ipc_isr example
+
+   This example code is in the Public Domain (or CC0 licensed, at your option.)
+
+   Unless required by applicable law or agreed to in writing, this
+   software is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
+   CONDITIONS OF ANY KIND, either express or implied.
+*/
+
+#include <stdio.h>
+#include <string.h>
+#include "esp_timer.h"
+#include "esp_log.h"
+#include "esp_ipc_isr.h"
+#include "sdkconfig.h"
+#if __XTENSA__
+#include "xtensa/config/core.h"
+#else
+#error "Doesn't support other architectures"
+#endif
+
+static const char* TAG = "example";
+
+typedef struct {
+    uint32_t regs[11];
+    uint32_t in[3];
+    uint32_t out[4];
+} arg_data_t;
+
+void get_ps_other_cpu(void* arg);
+void extended_ipc_isr_asm(void* arg);
+
+void app_main(void)
+{
+    ESP_LOGI(TAG, "Start");
+    uint32_t ps_other_cpu = 0;
+    ESP_LOGI(TAG, "call get_ps_other_cpu");
+    esp_ipc_isr_asm_call_blocking(get_ps_other_cpu, &ps_other_cpu);
+    ESP_LOGI(TAG, "PS_INTLEVEL = 0x%x", ps_other_cpu & XCHAL_PS_INTLEVEL_MASK);
+    ESP_LOGI(TAG, "PS_EXCM = 0x%x", (ps_other_cpu & XCHAL_PS_EXCM_MASK) >> XCHAL_PS_EXCM_SHIFT);
+    ESP_LOGI(TAG, "PS_UM = 0x%x", (ps_other_cpu & XCHAL_PS_UM_MASK) >> XCHAL_PS_UM_SHIFT);
+
+    ESP_LOGI(TAG, "call extended_ipc_isr_asm");
+    arg_data_t arg = { 0 };
+    arg.in[0] = 0x01;
+    arg.in[1] = 0x02;
+    arg.in[2] = 0x03;
+    ESP_LOGI(TAG, "in[0] = 0x%x", arg.in[0]);
+    ESP_LOGI(TAG, "in[1] = 0x%x", arg.in[1]);
+    ESP_LOGI(TAG, "in[2] = 0x%x", arg.in[2]);
+    esp_ipc_isr_asm_call_blocking(extended_ipc_isr_asm, (void*)&arg);
+    ESP_LOGI(TAG, "out[0] = (in[0] | in[1] | in[2]) = 0x%x", arg.out[0]);
+    assert(0x03 == arg.out[0]);
+    ESP_LOGI(TAG, "out[1] = (in[0] & in[1] & in[2]) = 0x%x", arg.out[1]);
+    assert(0x06 == arg.out[1]);
+    ESP_LOGI(TAG, "out[2] = in[2] = 0x%x", arg.out[2]);
+    assert(0x03 == arg.out[2]);
+    ESP_LOGI(TAG, "out[3] = PS of other cpu = 0x%x", arg.out[3]);
+    assert(ps_other_cpu == arg.out[3]);
+    ESP_LOGI(TAG, "End");
+}