[PATCH 2/2] arm: ux500: Add cpufreq support for u8500
Martin Persson
martin.persson at stericsson.com
Wed Dec 8 09:13:42 EST 2010
Signed-off-by: Martin Persson <martin.persson at stericsson.com>
Acked-by: Linus Walleij <linus.walleij at stericsson.com>
---
arch/arm/Kconfig | 1 +
arch/arm/mach-ux500/Makefile | 1 +
arch/arm/mach-ux500/cpu-db8500.c | 1 +
arch/arm/mach-ux500/cpufreq.c | 211 ++++++++++++++++++++++++++++++++++++++
4 files changed, 214 insertions(+), 0 deletions(-)
create mode 100644 arch/arm/mach-ux500/cpufreq.c
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index ca96a44..f5084e1 100644
--- a/arch/arm/Kconfig
+++ b/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
diff --git a/arch/arm/mach-ux500/Makefile b/arch/arm/mach-ux500/Makefile
index 9720e42..ac35668 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 b78970c..906aca4 100644
--- a/arch/arm/mach-ux500/cpu-db8500.c
+++ b/arch/arm/mach-ux500/cpu-db8500.c
@@ -165,6 +165,7 @@ void __init u8500_init_devices(void)
db8500_add_rtc();
+ 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 0000000..5c5b747
--- /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 at stericsson.com>
+ * Author: Martin Persson <martin.persson at stericsson.com>
+ * Author: Jonas Aaberg <jonas.aberg at 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);
--
1.7.2.2
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