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Subject[PATCH] cpuidle: add riscv cpuidle driver
Date
This patch adds a cpuidle driver for systems based RISCV architecture.
This patch supports state WFI. Other states will be supported in the
future.

Signed-off-by: liush <liush@allwinnertech.com>
---
arch/riscv/Kconfig | 7 +++++
arch/riscv/include/asm/cpuidle.h | 7 +++++
arch/riscv/kernel/Makefile | 1 +
arch/riscv/kernel/cpuidle.c | 8 ++++++
drivers/cpuidle/Kconfig | 5 ++++
drivers/cpuidle/Kconfig.riscv | 11 ++++++++
drivers/cpuidle/Makefile | 4 +++
drivers/cpuidle/cpuidle-riscv.c | 55 ++++++++++++++++++++++++++++++++++++++++
8 files changed, 98 insertions(+)
create mode 100644 arch/riscv/include/asm/cpuidle.h
create mode 100644 arch/riscv/kernel/cpuidle.c
create mode 100644 drivers/cpuidle/Kconfig.riscv
create mode 100644 drivers/cpuidle/cpuidle-riscv.c

diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index df18372..c7ddb9d 100644
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -86,6 +86,7 @@ config RISCV
select SPARSE_IRQ
select SYSCTL_EXCEPTION_TRACE
select THREAD_INFO_IN_TASK
+ select CPU_IDLE

config ARCH_MMAP_RND_BITS_MIN
default 18 if 64BIT
@@ -407,6 +408,12 @@ config BUILTIN_DTB
depends on RISCV_M_MODE
depends on OF

+menu "CPU Power Management"
+
+source "drivers/cpuidle/Kconfig"
+
+endmenu
+
menu "Power management options"

source "kernel/power/Kconfig"
diff --git a/arch/riscv/include/asm/cpuidle.h b/arch/riscv/include/asm/cpuidle.h
new file mode 100644
index 00000000..2599d2f
--- /dev/null
+++ b/arch/riscv/include/asm/cpuidle.h
@@ -0,0 +1,7 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __RISCV_CPUIDLE_H
+#define __RISCV_CPUIDLE_H
+
+extern void cpu_do_idle(void);
+
+#endif
diff --git a/arch/riscv/kernel/Makefile b/arch/riscv/kernel/Makefile
index dc93710..396ba9c 100644
--- a/arch/riscv/kernel/Makefile
+++ b/arch/riscv/kernel/Makefile
@@ -29,6 +29,7 @@ obj-y += riscv_ksyms.o
obj-y += stacktrace.o
obj-y += cacheinfo.o
obj-y += patch.o
+obj-y += cpuidle.o
obj-$(CONFIG_MMU) += vdso.o vdso/

obj-$(CONFIG_RISCV_M_MODE) += traps_misaligned.o
diff --git a/arch/riscv/kernel/cpuidle.c b/arch/riscv/kernel/cpuidle.c
new file mode 100644
index 00000000..a3289e7
--- /dev/null
+++ b/arch/riscv/kernel/cpuidle.c
@@ -0,0 +1,8 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <asm/cpuidle.h>
+
+void cpu_do_idle(void)
+{
+ __asm__ __volatile__ ("wfi");
+
+}
diff --git a/drivers/cpuidle/Kconfig b/drivers/cpuidle/Kconfig
index c0aeedd..f6be0fd 100644
--- a/drivers/cpuidle/Kconfig
+++ b/drivers/cpuidle/Kconfig
@@ -62,6 +62,11 @@ depends on PPC
source "drivers/cpuidle/Kconfig.powerpc"
endmenu

+menu "RISCV CPU Idle Drivers"
+depends on RISCV
+source "drivers/cpuidle/Kconfig.riscv"
+endmenu
+
config HALTPOLL_CPUIDLE
tristate "Halt poll cpuidle driver"
depends on X86 && KVM_GUEST
diff --git a/drivers/cpuidle/Kconfig.riscv b/drivers/cpuidle/Kconfig.riscv
new file mode 100644
index 00000000..e86d36b
--- /dev/null
+++ b/drivers/cpuidle/Kconfig.riscv
@@ -0,0 +1,11 @@
+# SPDX-License-Identifier: GPL-2.0-only
+#
+# RISCV CPU Idle drivers
+#
+config RISCV_CPUIDLE
+ bool "Generic RISCV CPU idle Driver"
+ select DT_IDLE_STATES
+ select CPU_IDLE_MULTIPLE_DRIVERS
+ help
+ Select this option to enable generic cpuidle driver for RISCV.
+ Now only support C0 State.
diff --git a/drivers/cpuidle/Makefile b/drivers/cpuidle/Makefile
index 26bbc5e..4c83c4e 100644
--- a/drivers/cpuidle/Makefile
+++ b/drivers/cpuidle/Makefile
@@ -34,3 +34,7 @@ obj-$(CONFIG_MIPS_CPS_CPUIDLE) += cpuidle-cps.o
# POWERPC drivers
obj-$(CONFIG_PSERIES_CPUIDLE) += cpuidle-pseries.o
obj-$(CONFIG_POWERNV_CPUIDLE) += cpuidle-powernv.o
+
+###############################################################################
+# RISCV drivers
+obj-$(CONFIG_RISCV_CPUIDLE) += cpuidle-riscv.o
diff --git a/drivers/cpuidle/cpuidle-riscv.c b/drivers/cpuidle/cpuidle-riscv.c
new file mode 100644
index 00000000..5dddcfa
--- /dev/null
+++ b/drivers/cpuidle/cpuidle-riscv.c
@@ -0,0 +1,55 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * RISC-V CPU idle driver.
+ *
+ * Copyright (C) 2020-2022 Allwinner Ltd
+ *
+ * Based on code - driver/cpuidle/cpuidle-at91.c
+ *
+ */
+#include <linux/cpuidle.h>
+#include <linux/cpumask.h>
+#include <linux/cpu_pm.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/slab.h>
+#include <linux/platform_device.h>
+#include <asm/cpuidle.h>
+
+#define MAX_IDLE_STATES 1
+
+/* TODO: Implement deeper idle states */
+static int riscv_low_level_suspend_enter(int state)
+{
+ return 0;
+}
+
+/* Actual code that puts the SoC in different idle states */
+static int riscv_enter_idle(struct cpuidle_device *dev,
+ struct cpuidle_driver *drv,
+ int index)
+{
+ return CPU_PM_CPU_IDLE_ENTER_PARAM(riscv_low_level_suspend_enter,
+ index, 0);
+}
+
+static struct cpuidle_driver riscv_idle_driver = {
+ .name = "riscv_idle",
+ .owner = THIS_MODULE,
+ .states[0] = {
+ .enter = riscv_enter_idle,
+ .exit_latency = 1,
+ .target_residency = 1,
+ .name = "WFI",
+ .desc = "RISCV WFI",
+ },
+ .state_count = MAX_IDLE_STATES,
+};
+
+static int __init riscv_cpuidle_init(void)
+{
+ return cpuidle_register(&riscv_idle_driver, NULL);
+}
+
+device_initcall(riscv_cpuidle_init);
--
2.7.4
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