From 75d8463399bd6628b63c91a0ee6092f3da504071 Mon Sep 17 00:00:00 2001
From: Anup Patel <anup.patel@wdc.com>
Date: Thu, 10 Feb 2022 11:19:40 +0530
Subject: [PATCH] RISC-V: Enable CPU_IDLE drivers

We force select CPU_PM and provide asm/cpuidle.h so that we can
use CPU IDLE drivers for Linux RISC-V kernel.

Starfive: Add deconfig for starfive jh7110

Signed-off-by: Anup Patel <anup.patel@wdc.com>
Signed-off-by: Anup Patel <apatel@vetanamicro.com>
Reviewed-by: Guo Ren <guoren@kernel.org>
Reviewed-by: Atish Patra <atishp@rivosinc.com>
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
Signed-off-by: mason.huo <mason.huo@starfivetech.com>
---
 arch/riscv/Kconfig                           |  7 +++++++
 arch/riscv/configs/starfive_jh7110_defconfig |  1 +
 arch/riscv/include/asm/cpuidle.h             | 24 ++++++++++++++++++++++++
 arch/riscv/kernel/process.c                  |  3 ++-
 4 files changed, 34 insertions(+), 1 deletion(-)
 create mode 100644 arch/riscv/include/asm/cpuidle.h

diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index 9ba99c5..6549dca 100644
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -45,6 +45,7 @@ config RISCV
 	select CLONE_BACKWARDS
 	select CLINT_TIMER if !MMU
 	select COMMON_CLK
+	select CPU_PM if CPU_IDLE
 	select EDAC_SUPPORT
 	select GENERIC_ARCH_TOPOLOGY if SMP
 	select GENERIC_ATOMIC64 if !64BIT
@@ -568,3 +569,9 @@ menu "Power management options"
 source "kernel/power/Kconfig"
 
 endmenu
+
+menu "CPU Power Management"
+
+source "drivers/cpuidle/Kconfig"
+
+endmenu
diff --git a/arch/riscv/configs/starfive_jh7110_defconfig b/arch/riscv/configs/starfive_jh7110_defconfig
index 0e2895c1..88a1cac 100644
--- a/arch/riscv/configs/starfive_jh7110_defconfig
+++ b/arch/riscv/configs/starfive_jh7110_defconfig
@@ -21,6 +21,7 @@ CONFIG_SOC_STARFIVE_JH7110=y
 CONFIG_SMP=y
 CONFIG_HZ_100=y
 CONFIG_PM=y
+CONFIG_CPU_IDLE=y
 # CONFIG_SECCOMP is not set
 CONFIG_MODULES=y
 CONFIG_MODULE_UNLOAD=y
diff --git a/arch/riscv/include/asm/cpuidle.h b/arch/riscv/include/asm/cpuidle.h
new file mode 100644
index 0000000..71fdc60
--- /dev/null
+++ b/arch/riscv/include/asm/cpuidle.h
@@ -0,0 +1,24 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2021 Allwinner Ltd
+ * Copyright (C) 2021 Western Digital Corporation or its affiliates.
+ */
+
+#ifndef _ASM_RISCV_CPUIDLE_H
+#define _ASM_RISCV_CPUIDLE_H
+
+#include <asm/barrier.h>
+#include <asm/processor.h>
+
+static inline void cpu_do_idle(void)
+{
+	/*
+	 * Add mb() here to ensure that all
+	 * IO/MEM accesses are completed prior
+	 * to entering WFI.
+	 */
+	mb();
+	wait_for_interrupt();
+}
+
+#endif
diff --git a/arch/riscv/kernel/process.c b/arch/riscv/kernel/process.c
index 03ac3aa..504b496 100644
--- a/arch/riscv/kernel/process.c
+++ b/arch/riscv/kernel/process.c
@@ -23,6 +23,7 @@
 #include <asm/string.h>
 #include <asm/switch_to.h>
 #include <asm/thread_info.h>
+#include <asm/cpuidle.h>
 
 register unsigned long gp_in_global __asm__("gp");
 
@@ -37,7 +38,7 @@ extern asmlinkage void ret_from_kernel_thread(void);
 
 void arch_cpu_idle(void)
 {
-	wait_for_interrupt();
+	cpu_do_idle();
 	raw_local_irq_enable();
 }
 
-- 
2.7.4