Merge branch 'fix/xtensa_nmi' into 'master'

fix(esp_hw_support): make the NMI interrupts available for the main application

Closes IDF-1891 and IDFGH-12631

See merge request espressif/esp-idf!32767

components/esp_hw_support/port/esp32/esp_cpu_intr.c

@@ -167,7 +167,7 @@ const static intr_desc_t intr_desc_table [SOC_CPU_INTR_NUM] = {
     [11] = { 3, ESP_CPU_INTR_TYPE_NA,    { ESP_CPU_INTR_DESC_FLAG_SPECIAL, ESP_CPU_INTR_DESC_FLAG_SPECIAL  } },
     [12] = { 1, ESP_CPU_INTR_TYPE_LEVEL, { 0,                              0                               } },
     [13] = { 1, ESP_CPU_INTR_TYPE_LEVEL, { 0,                              0                               } },
-    [14] = { 7, ESP_CPU_INTR_TYPE_LEVEL, { ESP_CPU_INTR_DESC_FLAG_RESVD,   ESP_CPU_INTR_DESC_FLAG_RESVD    } }, // NMI
+    [14] = { 7, ESP_CPU_INTR_TYPE_LEVEL, { 0,                              0                               } }, // NMI
 #if CONFIG_FREERTOS_CORETIMER_1
     [15] = { 3, ESP_CPU_INTR_TYPE_NA,    { ESP_CPU_INTR_DESC_FLAG_RESVD,   ESP_CPU_INTR_DESC_FLAG_RESVD    } },
 #else

components/esp_hw_support/port/esp32s2/esp_cpu_intr.c

@@ -44,7 +44,7 @@ const static intr_desc_t intr_desc_table [SOC_CPU_INTR_NUM] = {
     [12] = { 1, ESP_CPU_INTR_TYPE_LEVEL, 0                              },
     [13] = { 1, ESP_CPU_INTR_TYPE_LEVEL, 0                              },
     /* Interrupt 14 reserved for NMI (Non-Maskable Interrupts) */
-    [14] = { 7, ESP_CPU_INTR_TYPE_LEVEL, ESP_CPU_INTR_DESC_FLAG_RESVD   },
+    [14] = { 7, ESP_CPU_INTR_TYPE_LEVEL, 0                              },
 #if CONFIG_FREERTOS_CORETIMER_1
     [15] = { 3, ESP_CPU_INTR_TYPE_NA,    ESP_CPU_INTR_DESC_FLAG_RESVD   },
 #else

components/esp_hw_support/port/esp32s3/esp_cpu_intr.c

@@ -42,7 +42,7 @@ const static intr_desc_t intr_desc_table [SOC_CPU_INTR_NUM] = {
     [12] = { 1, ESP_CPU_INTR_TYPE_LEVEL, { 0,                              0                               } },
     [13] = { 1, ESP_CPU_INTR_TYPE_LEVEL, { 0,                              0                               } },
     /* Interrupt 14 reserved for NMI (Non-Maskable Interrupts) */
-    [14] = { 7, ESP_CPU_INTR_TYPE_LEVEL, { ESP_CPU_INTR_DESC_FLAG_RESVD,   ESP_CPU_INTR_DESC_FLAG_RESVD    } }, // NMI
+    [14] = { 7, ESP_CPU_INTR_TYPE_LEVEL, { 0,                              0                               } }, // NMI
     [15] = { 3, ESP_CPU_INTR_TYPE_NA,    { ESP_CPU_INTR_DESC_FLAG_SPECIAL, ESP_CPU_INTR_DESC_FLAG_SPECIAL  } },
     [16] = { 5, ESP_CPU_INTR_TYPE_NA,    { ESP_CPU_INTR_DESC_FLAG_SPECIAL, ESP_CPU_INTR_DESC_FLAG_SPECIAL  } },
     [17] = { 1, ESP_CPU_INTR_TYPE_LEVEL, { 0,                              0                               } },

docs/en/api-guides/hlinterrupts.rst

@@ -119,3 +119,5 @@ This will ensure the linker to always includes the file defining ``ld_include_my
 - In theory, medium priority interrupts could also be handled in this way. ESP-IDF does not support this yet.
 
 - To check Xtensa instruction set architecture (ISA), please refer to `Xtensa ISA Summary <https://www.cadence.com/content/dam/cadence-www/global/en_US/documents/tools/ip/tensilica-ip/isa-summary.pdf>`_.
+
+See :example:`system/nmi_isr` for an example of how to implement a custom NMI handler on Xtensa-based targets.

examples/system/.build-test-rules.yml

@@ -139,6 +139,11 @@ examples/system/light_sleep:
   disable:
     - if: SOC_LIGHT_SLEEP_SUPPORTED != 1
 
+examples/system/nmi_isr:
+  enable:
+    - if: IDF_TARGET_ARCH_XTENSA == 1
+      reason: test NMI for Xtensa targets only
+
 examples/system/ota/advanced_https_ota:
   disable:
     - if: IDF_TARGET in ["esp32h2", "esp32c61"]

examples/system/nmi_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 3.16)
+
+include($ENV{IDF_PATH}/tools/cmake/project.cmake)
+project(nmi_isr)

examples/system/nmi_isr/README.md

@@ -0,0 +1,40 @@
+| Supported Targets | ESP32 | ESP32-S2 | ESP32-S3 |
+| ----------------- | ----- | -------- | -------- |
+
+# NMI ISR Example
+
+This example demonstrates how to allocate and use non-maskable interrupt (NMI) on Xtensa-based targets. The `asm_funcs.S` file contains the ISR that will be run on the core that installed the NMI. The callback should be fairly simple and must be entirely written in assembly.
+
+Defining an NMI handler can be done by defining a routine named `xt_nmi`. That routine will be called via `call0` instruction, as such, before returning from the ISR, the return address register, `a0`, must be restored thanks to the instruction:
+
+```
+rsr a0, EXCSAVE + XCHAL_NMILEVEL
+```
+
+## How to use example
+
+### Hardware Required
+
+Example can run on any Xtensa-based ESP32 development board. Since the example uses GPIO19 as a bi-directional pin, make sure not to connect it to anything.
+
+### Configure the project
+
+No particular configuration is required to run this example, the default one is suitable.
+
+### 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
+
+```
+example: Start
+example: Success
+```

examples/system/nmi_isr/main/CMakeLists.txt

@@ -0,0 +1,4 @@
+idf_component_register(SRCS "nmi_isr_main.c"
+                            "asm_funcs.S"
+                    INCLUDE_DIRS "."
+                    WHOLE_ARCHIVE)

examples/system/nmi_isr/main/asm_funcs.S

@@ -0,0 +1,47 @@
+/*
+ * SPDX-FileCopyrightText: 2024 Espressif Systems (Shanghai) CO LTD
+ *
+ * SPDX-License-Identifier: Unlicense OR CC0-1.0
+ */
+
+#include <xtensa/coreasm.h>
+#include "soc/gpio_reg.h"
+#include "example_gpio.h"
+
+    .global nmi_triggered
+
+    .section    .bss
+nmi_triggered:
+    .space 4
+
+
+/**
+ * @brief This current ISR was called via `call0` instruction, so `a0` (return address)
+ * was altered. Fortunately, `a0` was saved in EXCSAVE registers, restore it before
+ * returning
+ */
+    .section    .iram1, "ax"
+    .align      4
+    .global     xt_nmi
+    .type       xt_nmi, @function
+xt_nmi:
+    addi    sp, sp, -16
+    s32i    a3, sp, 0
+
+    /* Set the interrupt flag to 1 */
+    movi    a0, nmi_triggered
+    movi    a3, 1
+    s32i    a3, a0, 0
+
+    /* Set the GPIO level back to low to prevent triggering an interrupt again */
+    movi    a0, GPIO_OUT_W1TC_REG
+    movi    a3, 1 << EXAMPLE_GPIO_IN
+    s32i    a3, a0, 0
+
+    /* Restore a3 and a0 before leaving*/
+    l32i    a3, sp, 0
+    addi    sp, sp, 16
+    rsr     a0, EXCSAVE + XCHAL_NMILEVEL
+
+    /* Return from NMI, we need to specify the level */
+    rfi     XCHAL_NMILEVEL

examples/system/nmi_isr/main/example_gpio.h

@@ -0,0 +1,9 @@
+
+/*
+ * SPDX-FileCopyrightText: 2024 Espressif Systems (Shanghai) CO LTD
+ *
+ * SPDX-License-Identifier: Unlicense OR CC0-1.0
+ */
+#pragma once
+
+#define EXAMPLE_GPIO_IN     19

examples/system/nmi_isr/main/nmi_isr_main.c

@@ -0,0 +1,63 @@
+/*
+ * SPDX-FileCopyrightText: 2024 Espressif Systems (Shanghai) CO LTD
+ *
+ * SPDX-License-Identifier: Unlicense OR CC0-1.0
+ */
+
+#include <stdio.h>
+#include <string.h>
+#include <inttypes.h>
+#include "freertos/FreeRTOSConfig.h"
+#include "freertos/FreeRTOS.h"
+#include "sdkconfig.h"
+#include "driver/gpio.h"
+#include "hal/gpio_ll.h"
+#include "soc/interrupts.h"
+#include "example_gpio.h"
+
+extern volatile int nmi_triggered;
+
+extern void xt_nmi(void*);
+
+void app_main(void)
+{
+    intr_handle_t handle;
+    esp_err_t err;
+
+    printf("example: Start\n");
+
+    /* Make sure we have a pull-down on the input GPIO to prevent noise (when disconnected) */
+    gpio_pulldown_en(EXAMPLE_GPIO_IN);
+    gpio_set_direction(EXAMPLE_GPIO_IN, GPIO_MODE_INPUT_OUTPUT);
+
+    /* Register the interrupt handler as an NMI. When registering high level interrupts,
+     * the interrupt allocator expects the handler passed as an argument to be NULL. */
+    err = esp_intr_alloc(ETS_GPIO_INTR_SOURCE, ESP_INTR_FLAG_IRAM | ESP_INTR_FLAG_NMI, NULL, NULL, &handle);
+    if (err != ESP_OK) {
+        printf("Failure: could not install NMI ISR, %d(0x%x)\n", err, err);
+        return;
+    }
+    gpio_set_intr_type(EXAMPLE_GPIO_IN, GPIO_INTR_HIGH_LEVEL);
+    gpio_intr_enable(EXAMPLE_GPIO_IN);
+
+    vTaskDelay(200 / portTICK_PERIOD_MS);
+
+    /* Disable interrupts on the CPU side and make sure the NMI is still triggered */
+    const uint32_t mask = esp_cpu_intr_get_enabled_mask();
+    esp_cpu_intr_disable(0xFFFFFFFF);
+    nmi_triggered = 0;
+
+    /* Setting EXAMPLE_GPIO_IN to 1 will trigger the NMI interrupt. */
+    gpio_set_level(EXAMPLE_GPIO_IN, 1);
+
+    /* Wait for the interrupt to occur */
+    while (nmi_triggered == 0) {
+        /* We cannot use vTaskDelay since the interrupts are disabled */
+    }
+
+    esp_cpu_intr_enable(mask);
+
+    gpio_intr_disable(EXAMPLE_GPIO_IN);
+    esp_intr_free(handle);
+    printf("example: Success\n");
+}

examples/system/nmi_isr/pytest_nmi_isr.py

@@ -0,0 +1,13 @@
+# SPDX-FileCopyrightText: 2024 Espressif Systems (Shanghai) CO LTD
+# SPDX-License-Identifier: CC0-1.0
+import pytest
+from pytest_embedded import Dut
+
+
+@pytest.mark.esp32
+@pytest.mark.esp32s2
+@pytest.mark.esp32s3
+@pytest.mark.generic
+def test_nmi_isr(dut: Dut) -> None:
+    dut.expect_exact('example: Start')
+    dut.expect_exact('example: Success')

tools/test_apps/system/esp_intr_dump/expected_output/esp32.txt

@@ -14,7 +14,7 @@ CPU 0 interrupt status:
  11     3    Level  CPU-internal
  12     1    Level  Free
  13     1    Level  Free
- 14     7    Level  Reserved
+ 14     7    Level  Free
  15     3    Level  CPU-internal
  16     5    Level  CPU-internal
  17     1    Level  Free
@@ -48,7 +48,7 @@ CPU 1 interrupt status:
  11     3    Level  CPU-internal
  12     1    Level  Free
  13     1    Level  Free
- 14     7    Level  Reserved
+ 14     7    Level  Free
  15     3    Level  CPU-internal
  16     5    Level  CPU-internal
  17     1    Level  Free

tools/test_apps/system/esp_intr_dump/expected_output/esp32s2.txt

@@ -14,7 +14,7 @@ CPU 0 interrupt status:
  11     3    Level  CPU-internal
  12     1    Level  Free
  13     1    Level  Free
- 14     7    Level  Reserved
+ 14     7    Level  Free
  15     3    Level  CPU-internal
  16     5    Level  CPU-internal
  17     1    Level  Free

tools/test_apps/system/esp_intr_dump/expected_output/esp32s3.txt

@@ -14,7 +14,7 @@ CPU 0 interrupt status:
  11     3    Level  CPU-internal
  12     1    Level  Free
  13     1    Level  Free
- 14     7    Level  Reserved
+ 14     7    Level  Free
  15     3    Level  CPU-internal
  16     5    Level  CPU-internal
  17     1    Level  Free
@@ -48,7 +48,7 @@ CPU 1 interrupt status:
  11     3    Level  CPU-internal
  12     1    Level  Free
  13     1    Level  Free
- 14     7    Level  Reserved
+ 14     7    Level  Free
  15     3    Level  CPU-internal
  16     5    Level  CPU-internal
  17     1    Level  Free