diff options
Diffstat (limited to 'drivers/cpufreq/db8500-cpufreq.c')
| -rw-r--r-- | drivers/cpufreq/db8500-cpufreq.c | 169 |
1 files changed, 169 insertions, 0 deletions
diff --git a/drivers/cpufreq/db8500-cpufreq.c b/drivers/cpufreq/db8500-cpufreq.c new file mode 100644 index 000000000000..d90456a809f9 --- /dev/null +++ b/drivers/cpufreq/db8500-cpufreq.c @@ -0,0 +1,169 @@ +/* + * Copyright (C) STMicroelectronics 2009 + * Copyright (C) ST-Ericsson SA 2010 + * + * License Terms: GNU General Public License v2 + * Author: Sundar Iyer <[email protected]> + * Author: Martin Persson <[email protected]> + * Author: Jonas Aaberg <[email protected]> + * + */ +#include <linux/kernel.h> +#include <linux/cpufreq.h> +#include <linux/delay.h> +#include <linux/slab.h> +#include <linux/mfd/db8500-prcmu.h> +#include <mach/id.h> + +static struct cpufreq_frequency_table freq_table[] = { + [0] = { + .index = 0, + .frequency = 300000, + }, + [1] = { + .index = 1, + .frequency = 600000, + }, + [2] = { + /* Used for MAX_OPP, if available */ + .index = 2, + .frequency = CPUFREQ_TABLE_END, + }, + [3] = { + .index = 3, + .frequency = CPUFREQ_TABLE_END, + }, +}; + +static enum arm_opp idx2opp[] = { + ARM_50_OPP, + ARM_100_OPP, + ARM_MAX_OPP +}; + +static struct freq_attr *db8500_cpufreq_attr[] = { + &cpufreq_freq_attr_scaling_available_freqs, + NULL, +}; + +static int db8500_cpufreq_verify_speed(struct cpufreq_policy *policy) +{ + return cpufreq_frequency_table_verify(policy, freq_table); +} + +static int db8500_cpufreq_target(struct cpufreq_policy *policy, + unsigned int target_freq, + unsigned int relation) +{ + struct cpufreq_freqs freqs; + unsigned int idx; + + /* scale the target frequency to one of the extremes supported */ + 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; + + /* Lookup the next frequency */ + if (cpufreq_frequency_table_target + (policy, freq_table, target_freq, relation, &idx)) { + return -EINVAL; + } + + freqs.old = policy->cur; + freqs.new = freq_table[idx].frequency; + freqs.cpu = policy->cpu; + + if (freqs.old == freqs.new) + return 0; + + /* pre-change notification */ + cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE); + + /* request the PRCM unit for opp change */ + if (prcmu_set_arm_opp(idx2opp[idx])) { + pr_err("db8500-cpufreq: Failed to set OPP level\n"); + return -EINVAL; + } + + /* post change notification */ + cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE); + + return 0; +} + +static unsigned int db8500_cpufreq_getspeed(unsigned int cpu) +{ + int i; + /* request the prcm to get the current ARM opp */ + for (i = 0; prcmu_get_arm_opp() != idx2opp[i]; i++) + ; + return freq_table[i].frequency; +} + +static int __cpuinit db8500_cpufreq_init(struct cpufreq_policy *policy) +{ + int res; + int i; + + BUILD_BUG_ON(ARRAY_SIZE(idx2opp) + 1 != ARRAY_SIZE(freq_table)); + + if (cpu_is_u8500v2() && !prcmu_is_u8400()) { + freq_table[0].frequency = 400000; + freq_table[1].frequency = 800000; + if (prcmu_has_arm_maxopp()) + freq_table[2].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 { + pr_err("db8500-cpufreq : Failed to read policy table\n"); + return res; + } + + policy->min = policy->cpuinfo.min_freq; + policy->max = policy->cpuinfo.max_freq; + policy->cur = db8500_cpufreq_getspeed(policy->cpu); + + for (i = 0; freq_table[i].frequency != policy->cur; i++) + ; + + 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 = 20 * 1000; /* in ns */ + + /* policy sharing between dual CPUs */ + cpumask_copy(policy->cpus, &cpu_present_map); + + policy->shared_type = CPUFREQ_SHARED_TYPE_ALL; + + return 0; +} + +static struct cpufreq_driver db8500_cpufreq_driver = { + .flags = CPUFREQ_STICKY, + .verify = db8500_cpufreq_verify_speed, + .target = db8500_cpufreq_target, + .get = db8500_cpufreq_getspeed, + .init = db8500_cpufreq_init, + .name = "DB8500", + .attr = db8500_cpufreq_attr, +}; + +static int __init db8500_cpufreq_register(void) +{ + if (!cpu_is_u8500v20_or_later()) + return -ENODEV; + + pr_info("cpufreq for DB8500 started\n"); + return cpufreq_register_driver(&db8500_cpufreq_driver); +} +device_initcall(db8500_cpufreq_register); |