drivers: timer: Export sys_clock_cycle_get_64() implementations

Export sys_clock_cycle_get_64() implementations to enable k_cycle_get_64()
calls from llext libraries.

Signed-off-by: Jyri Sarha <[email protected]>

Author: Jyri Sarha

drivers/timer/CMakeLists.txt

@@ -2,6 +2,7 @@
 
 zephyr_library()
 zephyr_library_sources(sys_clock_init.c)
+zephyr_library_sources_ifdef(CONFIG_LLEXT export.c)
 zephyr_library_sources_ifdef(CONFIG_ALTERA_AVALON_TIMER altera_avalon_timer_hal.c)
 zephyr_library_sources_ifdef(CONFIG_AMBIQ_STIMER_TIMER ambiq_stimer.c)
 zephyr_library_sources_ifdef(CONFIG_APIC_TIMER apic_timer.c)

drivers/timer/export.c

@@ -0,0 +1,13 @@
+/*
+ * Copyright (c) 2024 Intel Corporation
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <zephyr/drivers/timer/system_timer.h>
+#include <zephyr/llext/symbol.h>
+#include <limits.h>
+
+#ifdef CONFIG_TIMER_HAS_64BIT_CYCLE_COUNTER
+EXPORT_SYMBOL(sys_clock_cycle_get_64);
+#endif