freertos: add Kconfig FREERTOS_NO_AFFINITY constant

Use in place of tskNO_AFFINITY in Kconfig files

components/freertos/Kconfig

@@ -10,6 +10,12 @@ config FREERTOS_UNICORE
         This is needed when e.g. another process needs complete control
         over the second core.
 
+# This invisible config value sets the value of tskNO_AFFINITY in task.h.
+# Intended to be used as a constant from other Kconfig files.
+# Value is (32-bit) INT_MAX.
+config FREERTOS_NO_AFFINITY
+	hex
+	default 0x7FFFFFFF
 
 choice FREERTOS_CORETIMER
     prompt "Xtensa timer to use as the FreeRTOS tick source"

components/freertos/include/freertos/task.h

@@ -93,6 +93,9 @@ extern "C" {
 #define tskKERNEL_VERSION_MINOR 2
 #define tskKERNEL_VERSION_BUILD 0
 
+/**
+ * @brief Argument of xTaskCreatePinnedToCore indicating that task has no affinity
+ */
 #define tskNO_AFFINITY INT_MAX
 
 /**

components/freertos/port.c

@@ -123,6 +123,8 @@ extern void _xt_coproc_init(void);
     #define SYSTICK_INTR_ID (ETS_INTERNAL_TIMER1_INTR_SOURCE+ETS_INTERNAL_INTR_SOURCE_OFF)
 #endif
 
+_Static_assert(tskNO_AFFINITY == CONFIG_FREERTOS_NO_AFFINITY, "incorrect tskNO_AFFINITY value");
+
 /*-----------------------------------------------------------*/
 
 unsigned port_xSchedulerRunning[portNUM_PROCESSORS] = {0}; // Duplicate of inaccessible xSchedulerRunning; needed at startup to avoid counting nesting