[patch 26/38] loongarch: Select ARCH_HAS_RANDOM_ENTROPY

The only remaining non-architecture usage of get_cycles() is to provide
random_get_entropy().

Switch loongarch over to the new scheme of selecting ARCH_HAS_RANDOM_ENTROPY
and providing random_get_entropy() in asm/random.h.

Add 'asm/timex.h' includes to the relevant files, so the global include can
be removed once all architectures are converted over.

Signed-off-by: Thomas Gleixner <[email protected]>
Cc: Huacai Chen <[email protected]>
Cc: [email protected]
---
 arch/loongarch/Kconfig              |    1 +
 arch/loongarch/include/asm/random.h |   15 +++++++++++++++
 arch/loongarch/kernel/syscall.c     |    1 +
 arch/loongarch/lib/delay.c          |    2 +-
 4 files changed, 18 insertions(+), 1 deletion(-)

--- a/arch/loongarch/Kconfig
+++ b/arch/loongarch/Kconfig
@@ -26,6 +26,7 @@ config LOONGARCH
 	select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
 	select ARCH_HAS_PREEMPT_LAZY
 	select ARCH_HAS_PTE_SPECIAL
+	select ARCH_HAS_RANDOM_ENTROPY
 	select ARCH_HAS_SET_MEMORY
 	select ARCH_HAS_SET_DIRECT_MAP
 	select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST
--- /dev/null
+++ b/arch/loongarch/include/asm/random.h
@@ -0,0 +1,15 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2020-2022 Loongson Technology Corporation Limited
+ */
+#ifndef _ASM_RANDOM_H
+#define _ASM_RANDOM_H
+
+#include <asm/timex.h>
+
+static inline unsigned long random_get_entropy(void)
+{
+	return get_cycles();
+}
+
+#endif /*  _ASM_RANDOM_H */
--- a/arch/loongarch/kernel/syscall.c
+++ b/arch/loongarch/kernel/syscall.c
@@ -19,6 +19,7 @@
 #include <asm/loongarch.h>
 #include <asm/signal.h>
 #include <asm/switch_to.h>
+#include <asm/timex.h>
 #include <asm-generic/syscalls.h>
 
 #undef __SYSCALL
--- a/arch/loongarch/lib/delay.c
+++ b/arch/loongarch/lib/delay.c
@@ -5,9 +5,9 @@
 #include <linux/delay.h>
 #include <linux/export.h>
 #include <linux/smp.h>
-#include <linux/timex.h>
 
 #include <asm/processor.h>
+#include <asm/timex.h>
 
 void __delay(unsigned long cycles)
 {