ARM: imx: add i.MX7ULP cpuidle support

This patch adds cpuidle support for i.MX7ULP, 3 cpuidle
states supported as below:

1. WFI, just ARM wfi;
2. WAIT mode, mapped to SoC's partial stop mode #3;
3. STOP mode, mapped to SoC's partial stop mode #1.

In WAIT mode, system clock and bus clock will be enabled;
In STOP mode, system clock and bus clock will be disabled.

Signed-off-by: Anson Huang <Anson.Huang@nxp.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

arch/arm/mach-imx/Makefile

@@ -29,6 +29,7 @@ obj-$(CONFIG_SOC_IMX6SL) += cpuidle-imx6sl.o
 obj-$(CONFIG_SOC_IMX6SLL) += cpuidle-imx6sx.o
 obj-$(CONFIG_SOC_IMX6SX) += cpuidle-imx6sx.o
 obj-$(CONFIG_SOC_IMX6UL) += cpuidle-imx6sx.o
+obj-$(CONFIG_SOC_IMX7ULP) += cpuidle-imx7ulp.o
 endif
 
 ifdef CONFIG_SND_SOC_IMX_PCM_FIQ

arch/arm/mach-imx/common.h

@@ -72,6 +72,15 @@ enum mxc_cpu_pwr_mode {
 	STOP_POWER_OFF,		/* STOP + SRPG */
 };
 
+enum ulp_cpu_pwr_mode {
+	ULP_PM_HSRUN,    /* High speed run mode */
+	ULP_PM_RUN,      /* Run mode */
+	ULP_PM_WAIT,     /* Wait mode */
+	ULP_PM_STOP,     /* Stop mode */
+	ULP_PM_VLPS,     /* Very low power stop mode */
+	ULP_PM_VLLS,     /* very low leakage stop mode */
+};
+
 void imx_enable_cpu(int cpu, bool enable);
 void imx_set_cpu_jump(int cpu, void *jump_addr);
 u32 imx_get_cpu_arg(int cpu);
@@ -98,6 +107,7 @@ int imx6_set_lpm(enum mxc_cpu_pwr_mode mode);
 void imx6_set_int_mem_clk_lpm(bool enable);
 void imx6sl_set_wait_clk(bool enter);
 int imx_mmdc_get_ddr_type(void);
+int imx7ulp_set_lpm(enum ulp_cpu_pwr_mode mode);
 
 void imx_cpu_die(unsigned int cpu);
 int imx_cpu_kill(unsigned int cpu);

arch/arm/mach-imx/cpuidle-imx7ulp.c

@@ -0,0 +1,60 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2016 Freescale Semiconductor, Inc.
+ * Copyright 2017-2018 NXP
+ *   Anson Huang <Anson.Huang@nxp.com>
+ */
+
+#include <linux/cpuidle.h>
+#include <linux/module.h>
+#include <asm/cpuidle.h>
+
+#include "common.h"
+#include "cpuidle.h"
+
+static int imx7ulp_enter_wait(struct cpuidle_device *dev,
+			    struct cpuidle_driver *drv, int index)
+{
+	if (index == 1)
+		imx7ulp_set_lpm(ULP_PM_WAIT);
+	else
+		imx7ulp_set_lpm(ULP_PM_STOP);
+
+	cpu_do_idle();
+
+	imx7ulp_set_lpm(ULP_PM_RUN);
+
+	return index;
+}
+
+static struct cpuidle_driver imx7ulp_cpuidle_driver = {
+	.name = "imx7ulp_cpuidle",
+	.owner = THIS_MODULE,
+	.states = {
+		/* WFI */
+		ARM_CPUIDLE_WFI_STATE,
+		/* WAIT */
+		{
+			.exit_latency = 50,
+			.target_residency = 75,
+			.enter = imx7ulp_enter_wait,
+			.name = "WAIT",
+			.desc = "PSTOP2",
+		},
+		/* STOP */
+		{
+			.exit_latency = 100,
+			.target_residency = 150,
+			.enter = imx7ulp_enter_wait,
+			.name = "STOP",
+			.desc = "PSTOP1",
+		},
+	},
+	.state_count = 3,
+	.safe_state_index = 0,
+};
+
+int __init imx7ulp_cpuidle_init(void)
+{
+	return cpuidle_register(&imx7ulp_cpuidle_driver, NULL);
+}

arch/arm/mach-imx/cpuidle.h

@@ -15,6 +15,7 @@ extern int imx5_cpuidle_init(void);
 extern int imx6q_cpuidle_init(void);
 extern int imx6sl_cpuidle_init(void);
 extern int imx6sx_cpuidle_init(void);
+extern int imx7ulp_cpuidle_init(void);
 #else
 static inline int imx5_cpuidle_init(void)
 {
@@ -32,4 +33,8 @@ static inline int imx6sx_cpuidle_init(void)
 {
 	return 0;
 }
+static inline int imx7ulp_cpuidle_init(void)
+{
+	return 0;
+}
 #endif

arch/arm/mach-imx/mach-imx7ulp.c

@@ -10,6 +10,7 @@
 #include <asm/mach/arch.h>
 
 #include "common.h"
+#include "cpuidle.h"
 #include "hardware.h"
 
 static void __init imx7ulp_init_machine(void)
@@ -25,7 +26,13 @@ static const char *const imx7ulp_dt_compat[] __initconst = {
 	NULL,
 };
 
+static void __init imx7ulp_init_late(void)
+{
+	imx7ulp_cpuidle_init();
+}
+
 DT_MACHINE_START(IMX7ulp, "Freescale i.MX7ULP (Device Tree)")
 	.init_machine	= imx7ulp_init_machine,
 	.dt_compat	= imx7ulp_dt_compat,
+	.init_late	= imx7ulp_init_late,
 MACHINE_END

arch/arm/mach-imx/pm-imx7ulp.c

@@ -9,21 +9,60 @@
 #include <linux/of.h>
 #include <linux/of_address.h>
 
+#include "common.h"
+
 #define SMC_PMCTRL		0x10
 #define BP_PMCTRL_PSTOPO        16
 #define PSTOPO_PSTOP3		0x3
+#define PSTOPO_PSTOP2		0x2
+#define PSTOPO_PSTOP1		0x1
+#define BP_PMCTRL_RUNM		8
+#define RUNM_RUN		0
+#define BP_PMCTRL_STOPM		0
+#define STOPM_STOP		0
+
+#define BM_PMCTRL_PSTOPO	(3 << BP_PMCTRL_PSTOPO)
+#define BM_PMCTRL_RUNM		(3 << BP_PMCTRL_RUNM)
+#define BM_PMCTRL_STOPM		(7 << BP_PMCTRL_STOPM)
+
+static void __iomem *smc1_base;
+
+int imx7ulp_set_lpm(enum ulp_cpu_pwr_mode mode)
+{
+	u32 val = readl_relaxed(smc1_base + SMC_PMCTRL);
+
+	/* clear all */
+	val &= ~(BM_PMCTRL_RUNM | BM_PMCTRL_STOPM | BM_PMCTRL_PSTOPO);
+
+	switch (mode) {
+	case ULP_PM_RUN:
+		/* system/bus clock enabled */
+		val |= PSTOPO_PSTOP3 << BP_PMCTRL_PSTOPO;
+		break;
+	case ULP_PM_WAIT:
+		/* system clock disabled, bus clock enabled */
+		val |= PSTOPO_PSTOP2 << BP_PMCTRL_PSTOPO;
+		break;
+	case ULP_PM_STOP:
+		/* system/bus clock disabled */
+		val |= PSTOPO_PSTOP1 << BP_PMCTRL_PSTOPO;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	writel_relaxed(val, smc1_base + SMC_PMCTRL);
+
+	return 0;
+}
 
 void __init imx7ulp_pm_init(void)
 {
 	struct device_node *np;
-	void __iomem *smc1_base;
 
 	np = of_find_compatible_node(NULL, NULL, "fsl,imx7ulp-smc1");
 	smc1_base = of_iomap(np, 0);
 	WARN_ON(!smc1_base);
 
-	/* Partial Stop mode 3 with system/bus clock enabled */
-	writel_relaxed(PSTOPO_PSTOP3 << BP_PMCTRL_PSTOPO,
-		       smc1_base + SMC_PMCTRL);
-	iounmap(smc1_base);
+	imx7ulp_set_lpm(ULP_PM_RUN);
 }