kconfig: configure NUM_IRQS from Devicetree information

doc/build/kconfig/preprocessor-functions.rst

@@ -47,6 +47,7 @@ while the ``*_hex`` version returns a hexadecimal value starting with ``0x``.
    $(dt_compat_on_bus,<compatible string>,<bus>)
    $(dt_gpio_hogs_enabled)
    $(dt_has_compat,<compatible string>)
+   $(dt_highest_controller_irq_number,<node path>,<cell>)
    $(dt_node_array_prop_has_val,<node path>,<prop>,<value>)
    $(dt_node_array_prop_hex,<node path>,<prop>,<index>[,<unit>])
    $(dt_node_array_prop_int,<node path>,<prop>,<index>[,<unit>])

doc/releases/migration-guide-4.4.rst

@@ -941,6 +941,17 @@ STM32
   the ``cs-gpios`` or new ``st,soft-nss`` property operate in "Soft NSS" mode, while all other
   instances operate in "Hard NSS" mode.
 
+* :kconfig:option:`CONFIG_NUM_IRQS` is computed automatically based on active (``status = "okay";``)
+  devices by using the new ``dt_highest_controller_irq_number`` Kconfig preprocessor function.
+  Applications which register custom ISRs (using :c:macro:`IRQ_CONNECT()`) may encounter build
+  failures such as the following due to :kconfig:option:`CONFIG_NUM_IRQS` having a lower value:
+
+  .. code-block::
+
+    gen_isr_tables.py: error: IRQ 114 (offset=0) exceeds the maximum of 106
+
+  Explicitly set :kconfig:option:`CONFIG_NUM_IRQS` to an appropriate value to solve these issues.
+
 Timer
 =====
 

doc/releases/release-notes-4.4.rst

@@ -1415,6 +1415,11 @@ DeviceTree
 * :c:macro:`DT_CHILD_BY_UNIT_ADDR_INT`
 * :c:macro:`DT_INST_CHILD_BY_UNIT_ADDR_INT`
 
+Kconfig
+*******
+
+* Added new preprocessor function ``dt_highest_controller_irq_number`` (:github:`104819`)
+
 Kernel
 ******
 

scripts/kconfig/kconfigfunctions.py

@@ -1076,6 +1076,47 @@
 
     return "n"
 
+def dt_highest_controller_irq_number(kconfig, _, path, irq_cell_name):
+    """
+    Given the path to an interrupt controller node and the name of an
+    `interrupts` cell containing the "IRQ number" (an integer), returns
+    the highest "IRQ number" value among all enabled nodes that generate
+    an interrupt on the specified controller.
+
+    If the interrupt controller node does not exist, the provided cell name
+    is invalid, or the cell type is invalid, 0 will be returned.
+    """
+    if doc_mode or edt is None:
+        return "0"
+
+    try:
+        irqc = edt.get_node(path)
+    except edtlib.EDTError:
+        return "0"
+
+    irqns = set()
+    for node in irqc.required_by:
+        # Only examine active nodes
+        if node.status != "okay":
+            continue
+
+        for irq in node.interrupts:
+            # Only examine cells pointing to target interrupt controller
+            if irq.controller != irqc:
+                continue
+
+            if (irqn := irq.data.get(irq_cell_name)) is None:
+                continue
+
+            if not isinstance(irqn, int):
+                continue
+
+            irqns.add(irqn)
+
+    if len(irqns) == 0:
+        return "0"
+
+    return str(max(irqns))
 
 def normalize_upper(kconf, _, string):
     """
@@ -1258,6 +1299,7 @@
         "dt_gpio_hogs_enabled": (dt_gpio_hogs_enabled, 0, 0),
         "dt_chosen_partition_addr_int": (dt_chosen_partition_addr, 1, 3),
         "dt_chosen_partition_addr_hex": (dt_chosen_partition_addr, 1, 3),
+        "dt_highest_controller_irq_number": (dt_highest_controller_irq_number, 2, 2),
         "normalize_upper": (normalize_upper, 1, 1),
         "shields_list_contains": (shields_list_contains, 1, 1),
         "substring": (substring, 2, 3),

soc/st/stm32/Kconfig.defconfig

@@ -20,6 +20,15 @@ config CLOCK_CONTROL
 config CORTEX_M_SYSTICK
 	default n if STM32_LPTIM_TIMER
 
+# Compute IRQ table size automatically using DT for Cortex-M.
+# dt_highest_controller_irq_number() returns zero-based IRQn,
+# increment it to obtain the table size (= max IRQn + 1)
+DT_NVIC_PATH := /soc/interrupt-controller@e000e100
+DT_NVIC_MAX_IRQN := $(dt_highest_controller_irq_number,$(DT_NVIC_PATH),irq)
+
+configdefault NUM_IRQS
+	default $(inc,$(DT_NVIC_MAX_IRQN)) if $(dt_path_enabled,$(DT_NVIC_PATH))
+
 # Reduce kernel stack sizes to fit MCUs with 8 KiB RAM or less
 config MAIN_STACK_SIZE
 	default 320 if SRAM_SIZE <= 2

soc/st/stm32/stm32c0x/Kconfig.defconfig

@@ -5,8 +5,6 @@
 
 if SOC_SERIES_STM32C0X
 
-rsource "Kconfig.defconfig.stm32c0*"
-
 if PM
 
 config COUNTER

soc/st/stm32/stm32c5x/Kconfig.defconfig

@@ -5,8 +5,6 @@
 
 if SOC_SERIES_STM32C5X
 
-rsource "Kconfig.defconfig.stm32c5*"
-
 config ROM_START_OFFSET
 	default 0x400 if BOOTLOADER_MCUBOOT
 

soc/st/stm32/stm32f0x/Kconfig.defconfig

@@ -7,8 +7,6 @@
 
 if SOC_SERIES_STM32F0X
 
-rsource "Kconfig.defconfig.stm32f0*"
-
 config SRAM_VECTOR_TABLE
 	default y