tests: interrupt: add testcase for functions in the sw_isr_table

Validate the following functions in the sw_isr_table:
- z_get_sw_isr_table_idx
- z_get_sw_isr_device_from_irq
- z_get_sw_isr_irq_from_device

Signed-off-by: Yong Cong Sin <ycsin@meta.com>

tests/kernel/interrupt/CMakeLists.txt

@@ -22,3 +22,7 @@ target_sources_ifdef(CONFIG_SHARED_INTERRUPTS app PRIVATE src/static_shared_irq.
 if (CONFIG_SHARED_INTERRUPTS)
 target_sources_ifdef(CONFIG_DYNAMIC_INTERRUPTS app PRIVATE src/dynamic_shared_irq.c)
 endif()
+
+if (CONFIG_MULTI_LEVEL_INTERRUPTS)
+target_sources_ifdef(CONFIG_DYNAMIC_INTERRUPTS app PRIVATE src/sw_isr_table.c)
+endif()

tests/kernel/interrupt/src/sw_isr_table.c

@@ -0,0 +1,54 @@
+/*
+ * Copyright (c) 2023 Meta
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <zephyr/ztest.h>
+
+extern const struct _irq_parent_entry _lvl2_irq_list[];
+
+/**
+ * @brief Test sw_isr_table function
+ *
+ * @details Validates that:
+ * - z_get_sw_isr_device_from_irq() returns the parent interrupt controller for an IRQN
+ * - z_get_sw_isr_irq_from_device() returns the IRQN of a parent interrupt controller
+ * - z_get_sw_isr_table_idx() returns the corresponding SW ISR table index for an IRQN
+ */
+ZTEST(interrupt_feature, test_sw_isr_irq_parent_table)
+{
+	const struct device *parent_dev;
+	unsigned int parent_irq;
+	unsigned int parent_isr_offset;
+	const struct device *test_dev;
+	unsigned int test_irq;
+	unsigned int test_isr_offset;
+
+	for (size_t i = 0; i < CONFIG_NUM_2ND_LEVEL_AGGREGATORS; i++) {
+		parent_dev = _lvl2_irq_list[i].dev;
+		parent_irq = _lvl2_irq_list[i].irq;
+		parent_isr_offset = _lvl2_irq_list[i].offset;
+
+		for (unsigned int local_irq = 0;
+		     local_irq < BIT_MASK(CONFIG_2ND_LEVEL_INTERRUPT_BITS); local_irq++) {
+			test_irq = irq_to_level_2(local_irq) | parent_irq;
+			test_dev = z_get_sw_isr_device_from_irq(test_irq);
+			zassert_equal_ptr(parent_dev, test_dev, "expected dev: %p, got: %p",
+					  parent_dev, test_dev);
+		}
+
+		test_irq = z_get_sw_isr_irq_from_device(parent_dev);
+		zassert_equal(parent_irq, test_irq, "expected offset: %d, got: %d", parent_irq,
+			      test_irq);
+
+		for (unsigned int local_irq = 0;
+		     local_irq < BIT_MASK(CONFIG_2ND_LEVEL_INTERRUPT_BITS); local_irq++) {
+			test_irq = irq_to_level_2(local_irq) | parent_irq;
+			test_isr_offset = z_get_sw_isr_table_idx(test_irq);
+			zassert_equal(parent_isr_offset + local_irq, test_isr_offset,
+				      "expected offset: %d, got: %d", parent_isr_offset + local_irq,
+				      test_isr_offset);
+		}
+	}
+}