Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/drivers/irqchip/irq-ath79-misc.c b/drivers/irqchip/irq-ath79-misc.c
index aa72907..3d641bb 100644
--- a/drivers/irqchip/irq-ath79-misc.c
+++ b/drivers/irqchip/irq-ath79-misc.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  *  Atheros AR71xx/AR724x/AR913x MISC interrupt controller
  *
@@ -7,10 +8,6 @@
  *  Copyright (C) 2008 Imre Kaloz <kaloz@openwrt.org>
  *
  *  Parts of this file are based on Atheros' 2.6.15/2.6.31 BSP
- *
- *  This program is free software; you can redistribute it and/or modify it
- *  under the terms of the GNU General Public License version 2 as published
- *  by the Free Software Foundation.
  */
 
 #include <linux/irqchip.h>
@@ -22,6 +19,15 @@
 #define AR71XX_RESET_REG_MISC_INT_ENABLE	4
 
 #define ATH79_MISC_IRQ_COUNT			32
+#define ATH79_MISC_PERF_IRQ			5
+
+static int ath79_perfcount_irq;
+
+int get_c0_perfcount_int(void)
+{
+	return ath79_perfcount_irq;
+}
+EXPORT_SYMBOL_GPL(get_c0_perfcount_int);
 
 static void ath79_misc_irq_handler(struct irq_desc *desc)
 {
@@ -113,6 +119,8 @@
 {
 	void __iomem *base = domain->host_data;
 
+	ath79_perfcount_irq = irq_create_mapping(domain, ATH79_MISC_PERF_IRQ);
+
 	/* Disable and clear all interrupts */
 	__raw_writel(0, base + AR71XX_RESET_REG_MISC_INT_ENABLE);
 	__raw_writel(0, base + AR71XX_RESET_REG_MISC_INT_STATUS);