[CPUFREQ] EXYNOS: Make EXYNOS common cpufreq driver

To support various EXYNOS series SoCs commonly,
added exynos common structure.
exynos-cpufreq.c => EXYNOS series common cpufreq driver
exynos4210-cpufreq.c => EXYNOS4210 support cpufreq driver
Signed-off-by: Jaecheol Lee <jc.lee@samsung.com>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>
Signed-off-by: Dave Jones <davej@redhat.com>

arch/arm/mach-exynos/include/mach/cpufreq.h

+/* linux/arch/arm/mach-exynos/include/mach/cpufreq.h
+ *
+ * Copyright (c) 2010 Samsung Electronics Co., Ltd.
+ *		http://www.samsung.com
+ *
+ * EXYNOS - CPUFreq support
+ *
+ * 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.
+*/
+
+enum cpufreq_level_index {
+	L0, L1, L2, L3, L4,
+	L5, L6, L7, L8, L9,
+	L10, L11, L12, L13, L14,
+	L15, L16, L17, L18, L19,
+	L20,
+};
+
+struct exynos_dvfs_info {
+	unsigned long	mpll_freq_khz;
+	unsigned int	pll_safe_idx;
+	unsigned int	pm_lock_idx;
+	unsigned int	max_support_idx;
+	unsigned int	min_support_idx;
+	struct clk	*cpu_clk;
+	unsigned int	*volt_table;
+	struct cpufreq_frequency_table	*freq_table;
+	void (*set_freq)(unsigned int, unsigned int);
+	bool (*need_apll_change)(unsigned int, unsigned int);
+};
+
+extern int exynos4210_cpufreq_init(struct exynos_dvfs_info *);

drivers/cpufreq/Kconfig.arm

@@ -21,12 +21,19 @@ config ARM_S5PV210_CPUFREQ
 
 	  If in doubt, say N.
 
+config ARM_EXYNOS_CPUFREQ
+	bool "SAMSUNG EXYNOS SoCs"
+	depends on ARCH_EXYNOS
+	select ARM_EXYNOS4210_CPUFREQ if CPU_EXYNOS4210
+	default y
+	help
+	  This adds the CPUFreq driver common part for Samsung
+	  EXYNOS SoCs.
+
+	  If in doubt, say N.
+
 config ARM_EXYNOS4210_CPUFREQ
 	bool "Samsung EXYNOS4210"
-	depends on CPU_EXYNOS4210
-	default y
 	help
 	  This adds the CPUFreq driver for Samsung EXYNOS4210
 	  SoC (S5PV310 or S5PC210).
-
-	  If in doubt, say N.

drivers/cpufreq/Makefile

@@ -42,6 +42,7 @@ obj-$(CONFIG_X86_CPUFREQ_NFORCE2)	+= cpufreq-nforce2.o
 obj-$(CONFIG_UX500_SOC_DB8500)		+= db8500-cpufreq.o
 obj-$(CONFIG_ARM_S3C64XX_CPUFREQ)	+= s3c64xx-cpufreq.o
 obj-$(CONFIG_ARM_S5PV210_CPUFREQ)	+= s5pv210-cpufreq.o
+obj-$(CONFIG_ARM_EXYNOS_CPUFREQ)	+= exynos-cpufreq.o
 obj-$(CONFIG_ARM_EXYNOS4210_CPUFREQ)	+= exynos4210-cpufreq.o
 obj-$(CONFIG_ARCH_OMAP2PLUS)            += omap-cpufreq.o
 

drivers/cpufreq/exynos-cpufreq.c

+/*
+ * Copyright (c) 2010-2011 Samsung Electronics Co., Ltd.
+ *		http://www.samsung.com
+ *
+ * EXYNOS - CPU frequency scaling support for EXYNOS series
+ *
+ * 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/types.h>
+#include <linux/kernel.h>
+#include <linux/err.h>
+#include <linux/clk.h>
+#include <linux/io.h>
+#include <linux/slab.h>
+#include <linux/regulator/consumer.h>
+#include <linux/cpufreq.h>
+#include <linux/suspend.h>
+#include <linux/reboot.h>
+
+#include <mach/map.h>
+#include <mach/regs-clock.h>
+#include <mach/regs-mem.h>
+#include <mach/cpufreq.h>
+
+#include <plat/clock.h>
+#include <plat/pm.h>
+
+static struct exynos_dvfs_info *exynos_info;
+
+static struct regulator *arm_regulator;
+static struct cpufreq_freqs freqs;
+
+static unsigned int locking_frequency;
+static bool frequency_locked;
+static DEFINE_MUTEX(cpufreq_lock);
+
+int exynos_verify_speed(struct cpufreq_policy *policy)
+{
+	return cpufreq_frequency_table_verify(policy,
+					      exynos_info->freq_table);
+}
+
+unsigned int exynos_getspeed(unsigned int cpu)
+{
+	return clk_get_rate(exynos_info->cpu_clk) / 1000;
+}
+
+static int exynos_target(struct cpufreq_policy *policy,
+			  unsigned int target_freq,
+			  unsigned int relation)
+{
+	unsigned int index, old_index;
+	unsigned int arm_volt, safe_arm_volt = 0;
+	int ret = 0;
+	struct cpufreq_frequency_table *freq_table = exynos_info->freq_table;
+	unsigned int *volt_table = exynos_info->volt_table;
+	unsigned int mpll_freq_khz = exynos_info->mpll_freq_khz;
+
+	mutex_lock(&cpufreq_lock);
+
+	freqs.old = policy->cur;
+
+	if (frequency_locked && target_freq != locking_frequency) {
+		ret = -EAGAIN;
+		goto out;
+	}
+
+	if (cpufreq_frequency_table_target(policy, freq_table,
+					   freqs.old, relation, &old_index)) {
+		ret = -EINVAL;
+		goto out;
+	}
+
+	if (cpufreq_frequency_table_target(policy, freq_table,
+					   target_freq, relation, &index)) {
+		ret = -EINVAL;
+		goto out;
+	}
+
+	freqs.new = freq_table[index].frequency;
+	freqs.cpu = policy->cpu;
+
+	/*
+	 * ARM clock source will be changed APLL to MPLL temporary
+	 * To support this level, need to control regulator for
+	 * required voltage level
+	 */
+	if (exynos_info->need_apll_change != NULL) {
+		if (exynos_info->need_apll_change(old_index, index) &&
+		   (freq_table[index].frequency < mpll_freq_khz) &&
+		   (freq_table[old_index].frequency < mpll_freq_khz))
+			safe_arm_volt = volt_table[exynos_info->pll_safe_idx];
+	}
+	arm_volt = volt_table[index];
+
+	cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
+
+	/* When the new frequency is higher than current frequency */
+	if ((freqs.new > freqs.old) && !safe_arm_volt) {
+		/* Firstly, voltage up to increase frequency */
+		regulator_set_voltage(arm_regulator, arm_volt,
+				arm_volt);
+	}
+
+	if (safe_arm_volt)
+		regulator_set_voltage(arm_regulator, safe_arm_volt,
+				      safe_arm_volt);
+	if (freqs.new != freqs.old)
+		exynos_info->set_freq(old_index, index);
+
+	cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
+
+	/* When the new frequency is lower than current frequency */
+	if ((freqs.new < freqs.old) ||
+	   ((freqs.new > freqs.old) && safe_arm_volt)) {
+		/* down the voltage after frequency change */
+		regulator_set_voltage(arm_regulator, arm_volt,
+				arm_volt);
+	}
+
+out:
+	mutex_unlock(&cpufreq_lock);
+
+	return ret;
+}
+
+#ifdef CONFIG_PM
+static int exynos_cpufreq_suspend(struct cpufreq_policy *policy)
+{
+	return 0;
+}
+
+static int exynos_cpufreq_resume(struct cpufreq_policy *policy)
+{
+	return 0;
+}
+#endif
+
+/**
+ * exynos_cpufreq_pm_notifier - block CPUFREQ's activities in suspend-resume
+ *			context
+ * @notifier
+ * @pm_event
+ * @v
+ *
+ * While frequency_locked == true, target() ignores every frequency but
+ * locking_frequency. The locking_frequency value is the initial frequency,
+ * which is set by the bootloader. In order to eliminate possible
+ * inconsistency in clock values, we save and restore frequencies during
+ * suspend and resume and block CPUFREQ activities. Note that the standard
+ * suspend/resume cannot be used as they are too deep (syscore_ops) for
+ * regulator actions.
+ */
+static int exynos_cpufreq_pm_notifier(struct notifier_block *notifier,
+				       unsigned long pm_event, void *v)
+{
+	struct cpufreq_policy *policy = cpufreq_cpu_get(0); /* boot CPU */
+	static unsigned int saved_frequency;
+	unsigned int temp;
+
+	mutex_lock(&cpufreq_lock);
+	switch (pm_event) {
+	case PM_SUSPEND_PREPARE:
+		if (frequency_locked)
+			goto out;
+
+		frequency_locked = true;
+
+		if (locking_frequency) {
+			saved_frequency = exynos_getspeed(0);
+
+			mutex_unlock(&cpufreq_lock);
+			exynos_target(policy, locking_frequency,
+				      CPUFREQ_RELATION_H);
+			mutex_lock(&cpufreq_lock);
+		}
+		break;
+
+	case PM_POST_SUSPEND:
+		if (saved_frequency) {
+			/*
+			 * While frequency_locked, only locking_frequency
+			 * is valid for target(). In order to use
+			 * saved_frequency while keeping frequency_locked,
+			 * we temporarly overwrite locking_frequency.
+			 */
+			temp = locking_frequency;
+			locking_frequency = saved_frequency;
+
+			mutex_unlock(&cpufreq_lock);
+			exynos_target(policy, locking_frequency,
+				      CPUFREQ_RELATION_H);
+			mutex_lock(&cpufreq_lock);
+
+			locking_frequency = temp;
+		}
+		frequency_locked = false;
+		break;
+	}
+out:
+	mutex_unlock(&cpufreq_lock);
+
+	return NOTIFY_OK;
+}
+
+static struct notifier_block exynos_cpufreq_nb = {
+	.notifier_call = exynos_cpufreq_pm_notifier,
+};
+
+static int exynos_cpufreq_cpu_init(struct cpufreq_policy *policy)
+{
+	policy->cur = policy->min = policy->max = exynos_getspeed(policy->cpu);
+
+	cpufreq_frequency_table_get_attr(exynos_info->freq_table, policy->cpu);
+
+	/* set the transition latency value */
+	policy->cpuinfo.transition_latency = 100000;
+
+	/*
+	 * EXYNOS4 multi-core processors has 2 cores
+	 * that the frequency cannot be set independently.
+	 * Each cpu is bound to the same speed.
+	 * So the affected cpu is all of the cpus.
+	 */
+	if (num_online_cpus() == 1) {
+		cpumask_copy(policy->related_cpus, cpu_possible_mask);
+		cpumask_copy(policy->cpus, cpu_online_mask);
+	} else {
+		cpumask_setall(policy->cpus);
+	}
+
+	return cpufreq_frequency_table_cpuinfo(policy, exynos_info->freq_table);
+}
+
+static struct cpufreq_driver exynos_driver = {
+	.flags		= CPUFREQ_STICKY,
+	.verify		= exynos_verify_speed,
+	.target		= exynos_target,
+	.get		= exynos_getspeed,
+	.init		= exynos_cpufreq_cpu_init,
+	.name		= "exynos_cpufreq",
+#ifdef CONFIG_PM
+	.suspend	= exynos_cpufreq_suspend,
+	.resume		= exynos_cpufreq_resume,
+#endif
+};
+
+static int __init exynos_cpufreq_init(void)
+{
+	int ret = -EINVAL;
+
+	exynos_info = kzalloc(sizeof(struct exynos_dvfs_info), GFP_KERNEL);
+	if (!exynos_info)
+		return -ENOMEM;
+
+	if (soc_is_exynos4210())
+		ret = exynos4210_cpufreq_init(exynos_info);
+	else
+		pr_err("%s: CPU type not found\n", __func__);
+
+	if (ret)
+		goto err_vdd_arm;
+
+	if (exynos_info->set_freq == NULL) {
+		pr_err("%s: No set_freq function (ERR)\n", __func__);
+		goto err_vdd_arm;
+	}
+
+	arm_regulator = regulator_get(NULL, "vdd_arm");
+	if (IS_ERR(arm_regulator)) {
+		pr_err("%s: failed to get resource vdd_arm\n", __func__);
+		goto err_vdd_arm;
+	}
+
+	register_pm_notifier(&exynos_cpufreq_nb);
+
+	if (cpufreq_register_driver(&exynos_driver)) {
+		pr_err("%s: failed to register cpufreq driver\n", __func__);
+		goto err_cpufreq;
+	}
+
+	return 0;
+err_cpufreq:
+	unregister_pm_notifier(&exynos_cpufreq_nb);
+
+	if (!IS_ERR(arm_regulator))
+		regulator_put(arm_regulator);
+err_vdd_arm:
+	kfree(exynos_info);
+	pr_debug("%s: failed initialization\n", __func__);
+	return -EINVAL;
+}
+late_initcall(exynos_cpufreq_init);