ux500: Add cpufreq support for u8500

Signed-off-by: Martin Persson <martin.persson@stericsson.com>
Signed-off-by: Linus Walleij <linus.walleij@stericsson.com>

arch/arm/Kconfig

@@ -797,6 +797,7 @@ config ARCH_U8500
 	select GENERIC_CLOCKEVENTS
 	select COMMON_CLKDEV
 	select ARCH_REQUIRE_GPIOLIB
+	select ARCH_HAS_CPUFREQ
 	help
 	  Support for ST-Ericsson's Ux500 architecture
 

arch/arm/mach-ux500/Makefile

@@ -13,3 +13,4 @@ obj-$(CONFIG_LOCAL_TIMERS)	+= localtimer.o
 obj-$(CONFIG_REGULATOR_AB8500)	+= board-mop500-regulators.o
 obj-$(CONFIG_U5500_MODEM_IRQ)	+= modem_irq.o
 obj-$(CONFIG_U5500_MBOX)	+= mbox.o
+obj-$(CONFIG_CPU_FREQ)		+= cpufreq.o

arch/arm/mach-ux500/cpu-db8500.c

@@ -179,6 +179,7 @@ void __init u8500_init_devices(void)
 	db8500_add_rtc();
 	db8500_add_gpios();
 
+	platform_device_register_simple("cpufreq-u8500", -1, NULL, 0);
 	platform_add_devices(platform_devs, ARRAY_SIZE(platform_devs));
 
 	return ;

arch/arm/mach-ux500/cpufreq.c

+/*
+ * CPU frequency scaling for u8500
+ * Inspired by linux/arch/arm/mach-davinci/cpufreq.c
+ *
+ * Copyright (C) STMicroelectronics 2009
+ * Copyright (C) ST-Ericsson SA 2010
+ *
+ * License Terms: GNU General Public License v2
+ *
+ * Author: Sundar Iyer <sundar.iyer@stericsson.com>
+ * Author: Martin Persson <martin.persson@stericsson.com>
+ * Author: Jonas Aaberg <jonas.aberg@stericsson.com>
+ *
+ */
+
+#include <linux/platform_device.h>
+#include <linux/kernel.h>
+#include <linux/cpufreq.h>
+#include <linux/delay.h>
+
+#include <mach/hardware.h>
+#include <mach/prcmu.h>
+#include <mach/prcmu-defs.h>
+
+#define DRIVER_NAME "cpufreq-u8500"
+#define CPUFREQ_NAME "u8500"
+
+static struct device *dev;
+
+static struct cpufreq_frequency_table freq_table[] = {
+	[0] = {
+		.index = 0,
+		.frequency = 200000,
+	},
+	[1] = {
+		.index = 1,
+		.frequency = 300000,
+	},
+	[2] = {
+		.index = 2,
+		.frequency = 600000,
+	},
+	[3] = {
+		/* Used for CPU_OPP_MAX, if available */
+		.index = 3,
+		.frequency = CPUFREQ_TABLE_END,
+	},
+	[4] = {
+		.index = 4,
+		.frequency = CPUFREQ_TABLE_END,
+	},
+};
+
+static enum prcmu_cpu_opp index2opp[] = {
+	CPU_OPP_EXT_CLK,
+	CPU_OPP_50,
+	CPU_OPP_100,
+	CPU_OPP_MAX
+};
+
+static int u8500_cpufreq_verify_speed(struct cpufreq_policy *policy)
+{
+	return cpufreq_frequency_table_verify(policy, freq_table);
+}
+
+static int u8500_cpufreq_target(struct cpufreq_policy *policy,
+				unsigned int target_freq,
+				unsigned int relation)
+{
+	struct cpufreq_freqs freqs;
+	unsigned int index;
+	int ret = 0;
+
+	/*
+	 * Ensure desired rate is within allowed range.  Some govenors
+	 * (ondemand) will just pass target_freq=0 to get the minimum.
+	 */
+	if (target_freq < policy->cpuinfo.min_freq)
+		target_freq = policy->cpuinfo.min_freq;
+	if (target_freq > policy->cpuinfo.max_freq)
+		target_freq = policy->cpuinfo.max_freq;
+
+	ret = cpufreq_frequency_table_target(policy, freq_table,
+					     target_freq, relation, &index);
+	if (ret < 0) {
+		dev_err(dev, "Could not look up next frequency\n");
+		return ret;
+	}
+
+	freqs.old = policy->cur;
+	freqs.new = freq_table[index].frequency;
+	freqs.cpu = policy->cpu;
+
+	if (freqs.old == freqs.new) {
+		dev_dbg(dev, "Current and target frequencies are equal\n");
+		return 0;
+	}
+
+	dev_dbg(dev, "transition: %u --> %u\n", freqs.old, freqs.new);
+	cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
+
+	ret = prcmu_set_cpu_opp(index2opp[index]);
+	if (ret < 0) {
+		dev_err(dev, "Failed to set OPP level\n");
+		return ret;
+	}
+
+	cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
+
+	return ret;
+}
+
+static unsigned int u8500_cpufreq_getspeed(unsigned int cpu)
+{
+	int i;
+
+	for (i = 0; prcmu_get_cpu_opp() != index2opp[i]; i++)
+		;
+	return freq_table[i].frequency;
+}
+
+static int __cpuinit u8500_cpu_init(struct cpufreq_policy *policy)
+{
+	int res;
+
+	BUILD_BUG_ON(ARRAY_SIZE(index2opp) + 1 != ARRAY_SIZE(freq_table));
+
+	if (cpu_is_u8500v2()) {
+		freq_table[1].frequency = 400000;
+		freq_table[2].frequency = 800000;
+		if (prcmu_has_arm_maxopp())
+			freq_table[3].frequency = 1000000;
+	}
+
+	/* get policy fields based on the table */
+	res = cpufreq_frequency_table_cpuinfo(policy, freq_table);
+	if (!res)
+		cpufreq_frequency_table_get_attr(freq_table, policy->cpu);
+	else {
+		dev_err(dev, "u8500-cpufreq : Failed to read policy table\n");
+		return res;
+	}
+
+	policy->min = policy->cpuinfo.min_freq;
+	policy->max = policy->cpuinfo.max_freq;
+	policy->cur = u8500_cpufreq_getspeed(policy->cpu);
+	policy->governor = CPUFREQ_DEFAULT_GOVERNOR;
+
+	/*
+	 * FIXME : Need to take time measurement across the target()
+	 *	   function with no/some/all drivers in the notification
+	 *	   list.
+	 */
+	policy->cpuinfo.transition_latency = 200 * 1000; /* in ns */
+
+	/* policy sharing between dual CPUs */
+	cpumask_copy(policy->cpus, &cpu_present_map);
+
+	policy->shared_type = CPUFREQ_SHARED_TYPE_ALL;
+
+	return res;
+}
+
+static struct freq_attr *u8500_cpufreq_attr[] = {
+	&cpufreq_freq_attr_scaling_available_freqs,
+	NULL,
+};
+static int u8500_cpu_exit(struct cpufreq_policy *policy)
+{
+	cpufreq_frequency_table_put_attr(policy->cpu);
+	return 0;
+}
+
+static struct cpufreq_driver u8500_driver = {
+	.owner = THIS_MODULE,
+	.flags = CPUFREQ_STICKY,
+	.verify = u8500_cpufreq_verify_speed,
+	.target = u8500_cpufreq_target,
+	.get = u8500_cpufreq_getspeed,
+	.init = u8500_cpu_init,
+	.exit = u8500_cpu_exit,
+	.name = CPUFREQ_NAME,
+	.attr = u8500_cpufreq_attr,
+};
+
+static int __init u8500_cpufreq_probe(struct platform_device *pdev)
+{
+	dev = &pdev->dev;
+	return cpufreq_register_driver(&u8500_driver);
+}
+
+static int __exit u8500_cpufreq_remove(struct platform_device *pdev)
+{
+	return cpufreq_unregister_driver(&u8500_driver);
+}
+
+static struct platform_driver u8500_cpufreq_driver = {
+	.driver = {
+		.name	 = DRIVER_NAME,
+		.owner	 = THIS_MODULE,
+	},
+	.remove = __exit_p(u8500_cpufreq_remove),
+};
+
+static int __init u8500_cpufreq_init(void)
+{
+	return platform_driver_probe(&u8500_cpufreq_driver,
+				     &u8500_cpufreq_probe);
+}
+
+device_initcall(u8500_cpufreq_init);