ux500: Add cpufreq support for u8500

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

3 files changed, 213 insertions, 0 deletions

diff --git a/arch/arm/mach-ux500/Makefile b/arch/arm/mach-ux500/Makefile
index 93b0cf162017..841118335607 100644
--- a/arch/arm/mach-ux500/Makefile
+++ b/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
diff --git a/arch/arm/mach-ux500/cpu-db8500.c b/arch/arm/mach-ux500/cpu-db8500.c
index 658384c86933..c0f34a404c53 100644
--- a/arch/arm/mach-ux500/cpu-db8500.c
+++ b/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 ;
diff --git a/arch/arm/mach-ux500/cpufreq.c b/arch/arm/mach-ux500/cpufreq.c
new file mode 100644
index 000000000000..5c5b747f134d
--- /dev/null
+++ b/arch/arm/mach-ux500/cpufreq.c
@@ -0,0 +1,211 @@
+/*
+ * 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);