drivers/timer/xtensa_sys_timer: Add hook for old-style interrupt handling

We still have one platform using (for now) the pre-asm2 integration
where the timer interrupt was handled via custom assembly.  It calls a
function named "_timer_int_handler" always, not the one we register
with IRQ_CONNECT.

Signed-off-by: Andy Ross <[email protected]>

Author: Andy Ross

drivers/timer/xtensa_sys_timer.c

@@ -57,6 +57,17 @@ static void ccompare_isr(void *arg)
 	z_clock_announce(dticks);
 }
 
+/* The legacy Xtensa platform code handles the timer interrupt via a
+ * special path and must find it via this name.  Remove once ASM2 is
+ * pervasive.
+ */
+#ifndef CONFIG_XTENSA_ASM2
+void _timer_int_handler(void *arg)
+{
+	return ccompare_isr(arg);
+}
+#endif
+
 int z_clock_driver_init(struct device *device)
 {
 	IRQ_CONNECT(TIMER_IRQ, 0, ccompare_isr, 0, 0);