test(sdm): add iram safe test case

and with malloc comes from PSRAM by default (esp32p4)

components/esp_driver_sdm/test_apps/sigma_delta/main/CMakeLists.txt

@@ -4,8 +4,12 @@ if(CONFIG_SOC_LIGHT_SLEEP_SUPPORTED AND CONFIG_PM_ENABLE)
     list(APPEND srcs "test_sdm_sleep.cpp")
 endif()
 
+if(CONFIG_SDM_CTRL_FUNC_IN_IRAM)
+    list(APPEND srcs "test_sdm_iram.cpp")
+endif()
+
 # In order for the cases defined by `TEST_CASE` to be linked into the final elf,
 # the component can be registered as WHOLE_ARCHIVE
 idf_component_register(SRCS ${srcs}
-                       PRIV_REQUIRES unity esp_driver_sdm
+                       PRIV_REQUIRES unity esp_driver_sdm esp_psram
                        WHOLE_ARCHIVE)

components/esp_driver_sdm/test_apps/sigma_delta/main/test_sdm_iram.cpp

@@ -0,0 +1,56 @@
+/*
+ * SPDX-FileCopyrightText: 2026 Espressif Systems (Shanghai) CO LTD
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <stdio.h>
+#include "esp_err.h"
+#include "freertos/FreeRTOS.h"
+#include "freertos/task.h"
+#include "unity.h"
+#include "unity_test_utils.h"
+#include "esp_attr.h"
+#include "driver/sdm.h"
+
+typedef struct {
+    sdm_channel_handle_t chan;
+    esp_err_t ret;
+} sdm_iram_test_ctx_t;
+
+static void IRAM_ATTR test_set_pulse_density_iram(void *args)
+{
+    sdm_iram_test_ctx_t *ctx = (sdm_iram_test_ctx_t *)args;
+    // can't use TEST_ESP_OK here
+    ctx->ret = sdm_channel_set_pulse_density(ctx->chan, 127);
+}
+
+TEST_CASE("sdm_works_with_cache_disabled", "[sdm]")
+{
+    sdm_config_t config = {
+        .gpio_num = GPIO_NUM_0,
+        .clk_src = SDM_CLK_SRC_DEFAULT,
+        .sample_rate_hz = 1000000,
+        .flags = {
+            .invert_out = false,
+            .allow_pd = false,
+        },
+    };
+    sdm_channel_handle_t chan;
+    TEST_ESP_OK(sdm_new_channel(&config, &chan));
+    TEST_ESP_OK(sdm_channel_set_pulse_density(chan, 0));
+    TEST_ESP_OK(sdm_channel_enable(chan));
+    vTaskDelay(pdMS_TO_TICKS(500));
+
+    printf("change pulse density in IRAM\r\n");
+    sdm_iram_test_ctx_t ctx = {
+        .chan = chan,
+        .ret = ESP_FAIL,
+    };
+    unity_utils_run_cache_disable_stub(test_set_pulse_density_iram, &ctx);
+    TEST_ESP_OK(ctx.ret);
+    vTaskDelay(pdMS_TO_TICKS(500));
+
+    TEST_ESP_OK(sdm_channel_disable(chan));
+    TEST_ESP_OK(sdm_del_channel(chan));
+}

components/esp_driver_sdm/test_apps/sigma_delta/sdkconfig.defaults.esp32p4

@@ -0,0 +1,3 @@
+CONFIG_SPIRAM=y
+CONFIG_SPIRAM_MODE_HEX=y
+CONFIG_SPIRAM_MALLOC_ALWAYSINTERNAL=0