[PATCH v9 13/15] arm64: support cpuidle-haltpoll

[Ankur Arora <ankur.a.arora@oracle.com>]

Add architectural support for the cpuidle-haltpoll driver by defining
arch_haltpoll_*(). Also define ARCH_CPUIDLE_HALTPOLL to allow
cpuidle-haltpoll to be selected.

Tested-by: Haris Okanovic <harisokn@amazon.com>
Tested-by: Misono Tomohiro <misono.tomohiro@fujitsu.com>
Signed-off-by: Ankur Arora <ankur.a.arora@oracle.com>
---
 arch/arm64/Kconfig                        |  6 ++++++
 arch/arm64/include/asm/cpuidle_haltpoll.h | 20 ++++++++++++++++++++
 2 files changed, 26 insertions(+)
 create mode 100644 arch/arm64/include/asm/cpuidle_haltpoll.h

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 43762c68e357..bd00647f6013 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -2428,6 +2428,12 @@ config ARCH_HIBERNATION_HEADER
 config ARCH_SUSPEND_POSSIBLE
 	def_bool y
 
+config ARCH_CPUIDLE_HALTPOLL
+	bool "Enable selection of the cpuidle-haltpoll driver"
+	help
+	  cpuidle-haltpoll allows for adaptive polling based on
+	  current load before entering the idle state.
+
 endmenu # "Power management options"
 
 menu "CPU Power Management"
diff --git a/arch/arm64/include/asm/cpuidle_haltpoll.h b/arch/arm64/include/asm/cpuidle_haltpoll.h
new file mode 100644
index 000000000000..aa01ae9ad5dd
--- /dev/null
+++ b/arch/arm64/include/asm/cpuidle_haltpoll.h
@@ -0,0 +1,20 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#ifndef _ARCH_HALTPOLL_H
+#define _ARCH_HALTPOLL_H
+
+static inline void arch_haltpoll_enable(unsigned int cpu) { }
+static inline void arch_haltpoll_disable(unsigned int cpu) { }
+
+static inline bool arch_haltpoll_want(bool force)
+{
+	/*
+	 * Enabling haltpoll requires KVM support for arch_haltpoll_enable(),
+	 * arch_haltpoll_disable().
+	 *
+	 * Given that that's missing right now, only allow force loading for
+	 * haltpoll.
+	 */
+	return force;
+}
+#endif
-- 
2.43.5