diff options
Diffstat (limited to 'drivers/cpufreq')
| -rw-r--r-- | drivers/cpufreq/db8500-cpufreq.c | 210 |
1 files changed, 210 insertions, 0 deletions
diff --git a/drivers/cpufreq/db8500-cpufreq.c b/drivers/cpufreq/db8500-cpufreq.c new file mode 100644 index 0000000..d196939 --- /dev/null +++ b/drivers/cpufreq/db8500-cpufreq.c @@ -0,0 +1,210 @@ +/* + * 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 <linux/mfd/db8500-prcmu.h> + +#include <mach/hardware.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); |
