[PATCH 2/2] arm: imx: support arm power off in cpuidle for i.mx6sx
Anson Huang
b20788 at freescale.com
Mon Dec 8 21:28:39 PST 2014
This patch introduces an independent cpuidle driver for
i.MX6SX, and supports arm power off in idle, totally
3 levels of cpuidle are supported as below:
1. ARM WFI;
2. SOC in WAIT mode;
3. SOC in WAIT mode + ARM power off.
ARM power off can save at least 5mW power.
Signed-off-by: Anson Huang <b20788 at freescale.com>
---
arch/arm/mach-imx/Makefile | 3 +-
arch/arm/mach-imx/common.h | 4 ++
arch/arm/mach-imx/cpuidle-imx6sx.c | 107 ++++++++++++++++++++++++++++++++++++
arch/arm/mach-imx/cpuidle.h | 5 ++
arch/arm/mach-imx/gpc.c | 25 ++++++++-
arch/arm/mach-imx/mach-imx6sx.c | 2 +-
arch/arm/mach-imx/pm-imx6.c | 2 +-
7 files changed, 142 insertions(+), 6 deletions(-)
create mode 100644 arch/arm/mach-imx/cpuidle-imx6sx.c
diff --git a/arch/arm/mach-imx/Makefile b/arch/arm/mach-imx/Makefile
index f5ac685..8d1b101 100644
--- a/arch/arm/mach-imx/Makefile
+++ b/arch/arm/mach-imx/Makefile
@@ -32,8 +32,7 @@ ifeq ($(CONFIG_CPU_IDLE),y)
obj-$(CONFIG_SOC_IMX5) += cpuidle-imx5.o
obj-$(CONFIG_SOC_IMX6Q) += cpuidle-imx6q.o
obj-$(CONFIG_SOC_IMX6SL) += cpuidle-imx6sl.o
-# i.MX6SX reuses i.MX6Q cpuidle driver
-obj-$(CONFIG_SOC_IMX6SX) += cpuidle-imx6q.o
+obj-$(CONFIG_SOC_IMX6SX) += cpuidle-imx6sx.o
endif
ifdef CONFIG_SND_IMX_SOC
diff --git a/arch/arm/mach-imx/common.h b/arch/arm/mach-imx/common.h
index 59ce8f3..b0da5e9 100644
--- a/arch/arm/mach-imx/common.h
+++ b/arch/arm/mach-imx/common.h
@@ -70,6 +70,10 @@ void imx_set_soc_revision(unsigned int rev);
unsigned int imx_get_soc_revision(void);
void imx_init_revision_from_anatop(void);
struct device *imx_soc_device_init(void);
+void imx6q_enable_rbc(bool enable);
+void imx_gpc_set_arm_power_in_lpm(bool power_off);
+void imx_gpc_set_arm_power_up_timing(u32 sw2iso, u32 sw);
+void imx_gpc_set_arm_power_down_timing(u32 sw2iso, u32 sw);
enum mxc_cpu_pwr_mode {
WAIT_CLOCKED, /* wfi only */
diff --git a/arch/arm/mach-imx/cpuidle-imx6sx.c b/arch/arm/mach-imx/cpuidle-imx6sx.c
new file mode 100644
index 0000000..58106cc
--- /dev/null
+++ b/arch/arm/mach-imx/cpuidle-imx6sx.c
@@ -0,0 +1,107 @@
+/*
+ * Copyright (C) 2014 Freescale Semiconductor, Inc.
+ *
+ * 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/cpuidle.h>
+#include <linux/cpu_pm.h>
+#include <linux/module.h>
+#include <asm/cpuidle.h>
+#include <asm/proc-fns.h>
+#include <asm/suspend.h>
+
+#include "common.h"
+#include "cpuidle.h"
+
+static int imx6sx_idle_finish(unsigned long val)
+{
+ cpu_do_idle();
+
+ return 0;
+}
+
+static int imx6sx_enter_wait(struct cpuidle_device *dev,
+ struct cpuidle_driver *drv, int index)
+{
+ imx6q_set_lpm(WAIT_UNCLOCKED);
+
+ switch (index) {
+ case 1:
+ cpu_do_idle();
+ break;
+ case 2:
+ imx6q_enable_rbc(true);
+ imx_gpc_set_arm_power_in_lpm(true);
+ imx_set_cpu_jump(0, v7_cpu_resume);
+ /* Need to notify there is a cpu pm operation. */
+ cpu_pm_enter();
+ cpu_cluster_pm_enter();
+
+ cpu_suspend(0, imx6sx_idle_finish);
+
+ cpu_cluster_pm_exit();
+ cpu_pm_exit();
+ imx_gpc_set_arm_power_in_lpm(false);
+ imx6q_enable_rbc(false);
+ break;
+ default:
+ break;
+ }
+
+ imx6q_set_lpm(WAIT_CLOCKED);
+
+ return index;
+}
+
+static struct cpuidle_driver imx6sx_cpuidle_driver = {
+ .name = "imx6sx_cpuidle",
+ .owner = THIS_MODULE,
+ .states = {
+ /* WFI */
+ ARM_CPUIDLE_WFI_STATE,
+ /* WAIT */
+ {
+ .exit_latency = 50,
+ .target_residency = 75,
+ .flags = CPUIDLE_FLAG_TIME_VALID |
+ CPUIDLE_FLAG_TIMER_STOP,
+ .enter = imx6sx_enter_wait,
+ .name = "WAIT",
+ .desc = "Clock off",
+ },
+ /* WAIT + ARM power off */
+ {
+ /*
+ * ARM gating 31us * 5 + RBC clear 65us
+ * and some margin for SW execution, here set it
+ * to 300us.
+ */
+ .exit_latency = 300,
+ .target_residency = 500,
+ .flags = CPUIDLE_FLAG_TIME_VALID,
+ .enter = imx6sx_enter_wait,
+ .name = "LOW-POWER-IDLE",
+ .desc = "ARM power off",
+ },
+ },
+ .state_count = 3,
+ .safe_state_index = 0,
+};
+
+int __init imx6sx_cpuidle_init(void)
+{
+ imx6q_enable_rbc(false);
+ /*
+ * set ARM power up/down timing to the fastest,
+ * sw2iso and sw can be set to one 32K cycle = 31us
+ * except for power up sw2iso which need to be
+ * larger than LDO ramp up time.
+ */
+ imx_gpc_set_arm_power_up_timing(2, 1);
+ imx_gpc_set_arm_power_down_timing(1, 1);
+
+ return cpuidle_register(&imx6sx_cpuidle_driver, NULL);
+}
diff --git a/arch/arm/mach-imx/cpuidle.h b/arch/arm/mach-imx/cpuidle.h
index 24e3367..f914012 100644
--- a/arch/arm/mach-imx/cpuidle.h
+++ b/arch/arm/mach-imx/cpuidle.h
@@ -14,6 +14,7 @@
extern int imx5_cpuidle_init(void);
extern int imx6q_cpuidle_init(void);
extern int imx6sl_cpuidle_init(void);
+extern int imx6sx_cpuidle_init(void);
#else
static inline int imx5_cpuidle_init(void)
{
@@ -27,4 +28,8 @@ static inline int imx6sl_cpuidle_init(void)
{
return 0;
}
+static inline int imx6sx_cpuidle_init(void)
+{
+ return 0;
+}
#endif
diff --git a/arch/arm/mach-imx/gpc.c b/arch/arm/mach-imx/gpc.c
index 82ea74e..5fa43d2 100644
--- a/arch/arm/mach-imx/gpc.c
+++ b/arch/arm/mach-imx/gpc.c
@@ -20,6 +20,10 @@
#define GPC_IMR1 0x008
#define GPC_PGC_CPU_PDN 0x2a0
+#define GPC_PGC_CPU_PUPSCR 0x2a4
+#define GPC_PGC_CPU_PDNSCR 0x2a8
+#define GPC_PGC_SW2ISO_SHIFT 0x8
+#define GPC_PGC_SW_SHIFT 0x0
#define IMR_NUM 4
@@ -27,6 +31,23 @@ static void __iomem *gpc_base;
static u32 gpc_wake_irqs[IMR_NUM];
static u32 gpc_saved_imrs[IMR_NUM];
+void imx_gpc_set_arm_power_up_timing(u32 sw2iso, u32 sw)
+{
+ writel_relaxed((sw2iso << GPC_PGC_SW2ISO_SHIFT) |
+ (sw << GPC_PGC_SW_SHIFT), gpc_base + GPC_PGC_CPU_PUPSCR);
+}
+
+void imx_gpc_set_arm_power_down_timing(u32 sw2iso, u32 sw)
+{
+ writel_relaxed((sw2iso << GPC_PGC_SW2ISO_SHIFT) |
+ (sw << GPC_PGC_SW_SHIFT), gpc_base + GPC_PGC_CPU_PDNSCR);
+}
+
+void imx_gpc_set_arm_power_in_lpm(bool power_off)
+{
+ writel_relaxed(power_off, gpc_base + GPC_PGC_CPU_PDN);
+}
+
void imx_gpc_pre_suspend(bool arm_power_off)
{
void __iomem *reg_imr1 = gpc_base + GPC_IMR1;
@@ -34,7 +55,7 @@ void imx_gpc_pre_suspend(bool arm_power_off)
/* Tell GPC to power off ARM core when suspend */
if (arm_power_off)
- writel_relaxed(0x1, gpc_base + GPC_PGC_CPU_PDN);
+ imx_gpc_set_arm_power_in_lpm(arm_power_off);
for (i = 0; i < IMR_NUM; i++) {
gpc_saved_imrs[i] = readl_relaxed(reg_imr1 + i * 4);
@@ -48,7 +69,7 @@ void imx_gpc_post_resume(void)
int i;
/* Keep ARM core powered on for other low-power modes */
- writel_relaxed(0x0, gpc_base + GPC_PGC_CPU_PDN);
+ imx_gpc_set_arm_power_in_lpm(false);
for (i = 0; i < IMR_NUM; i++)
writel_relaxed(gpc_saved_imrs[i], reg_imr1 + i * 4);
diff --git a/arch/arm/mach-imx/mach-imx6sx.c b/arch/arm/mach-imx/mach-imx6sx.c
index 7a96c65..66988eb 100644
--- a/arch/arm/mach-imx/mach-imx6sx.c
+++ b/arch/arm/mach-imx/mach-imx6sx.c
@@ -90,7 +90,7 @@ static void __init imx6sx_init_irq(void)
static void __init imx6sx_init_late(void)
{
- imx6q_cpuidle_init();
+ imx6sx_cpuidle_init();
if (IS_ENABLED(CONFIG_ARM_IMX6Q_CPUFREQ))
platform_device_register_simple("imx6q-cpufreq", -1, NULL, 0);
diff --git a/arch/arm/mach-imx/pm-imx6.c b/arch/arm/mach-imx/pm-imx6.c
index 671e2a9..cab80e2 100644
--- a/arch/arm/mach-imx/pm-imx6.c
+++ b/arch/arm/mach-imx/pm-imx6.c
@@ -205,7 +205,7 @@ void imx6q_set_int_mem_clk_lpm(bool enable)
writel_relaxed(val, ccm_base + CGPR);
}
-static void imx6q_enable_rbc(bool enable)
+void imx6q_enable_rbc(bool enable)
{
u32 val;
--
1.7.9.5
More information about the linux-arm-kernel
mailing list