/******************************************************************************
*
* enable_ccnt_522.c
*
* This Linux kernel module, when loaded,
* enables the ARM Cortex-A53 cycle counter
* on every core of the CPU.
*
* Modified November 29, 2021 by Marion Sudvarg
*
******************************************************************************/

#include <linux/init.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/types.h>
#include <asm/perfmon.h>

static bool cycles_64_bit = 1;
static bool count_every_64 = 0;

static void enable_ccnt(void *info) {
        pmccntr_enable_once(cycles_64_bit, count_every_64);
}

static int enable_ccnt_init(void) {

        on_each_cpu(enable_ccnt,NULL,0);

        printk (KERN_INFO "Cycle Counter Enabled\n");

        return 0;
}

static void enable_ccnt_exit(void) {
}

module_init(enable_ccnt_init);
module_exit(enable_ccnt_exit);

MODULE_LICENSE("GPL v2");
MODULE_AUTHOR("Marion Sudvarg");
MODULE_DESCRIPTION("Enable ARM Cortex-A53 Cycle Counter");