171 lines
4.1 KiB
C
171 lines
4.1 KiB
C
/*
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* Copyright (C) STMicroelectronics 2009
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* Copyright (C) ST-Ericsson SA 2010
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*
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* License Terms: GNU General Public License v2
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* Author: Sundar Iyer <sundar.iyer@stericsson.com>
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* Author: Martin Persson <martin.persson@stericsson.com>
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* Author: Jonas Aaberg <jonas.aberg@stericsson.com>
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*
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*/
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#include <linux/kernel.h>
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#include <linux/cpufreq.h>
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#include <linux/delay.h>
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#include <linux/slab.h>
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#include <linux/mfd/dbx500-prcmu.h>
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#include <mach/id.h>
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static struct cpufreq_frequency_table freq_table[] = {
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[0] = {
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.index = 0,
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.frequency = 200000,
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},
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[1] = {
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.index = 1,
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.frequency = 400000,
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},
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[2] = {
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.index = 2,
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.frequency = 800000,
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},
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[3] = {
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/* Used for MAX_OPP, if available */
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.index = 3,
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.frequency = CPUFREQ_TABLE_END,
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},
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[4] = {
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.index = 4,
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.frequency = CPUFREQ_TABLE_END,
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},
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};
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static enum arm_opp idx2opp[] = {
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ARM_EXTCLK,
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ARM_50_OPP,
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ARM_100_OPP,
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ARM_MAX_OPP
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};
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static struct freq_attr *db8500_cpufreq_attr[] = {
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&cpufreq_freq_attr_scaling_available_freqs,
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NULL,
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};
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static int db8500_cpufreq_verify_speed(struct cpufreq_policy *policy)
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{
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return cpufreq_frequency_table_verify(policy, freq_table);
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}
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static int db8500_cpufreq_target(struct cpufreq_policy *policy,
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unsigned int target_freq,
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unsigned int relation)
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{
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struct cpufreq_freqs freqs;
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unsigned int idx;
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/* scale the target frequency to one of the extremes supported */
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if (target_freq < policy->cpuinfo.min_freq)
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target_freq = policy->cpuinfo.min_freq;
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if (target_freq > policy->cpuinfo.max_freq)
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target_freq = policy->cpuinfo.max_freq;
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/* Lookup the next frequency */
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if (cpufreq_frequency_table_target
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(policy, freq_table, target_freq, relation, &idx)) {
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return -EINVAL;
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}
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freqs.old = policy->cur;
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freqs.new = freq_table[idx].frequency;
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if (freqs.old == freqs.new)
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return 0;
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/* pre-change notification */
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for_each_cpu(freqs.cpu, policy->cpus)
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cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
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/* request the PRCM unit for opp change */
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if (prcmu_set_arm_opp(idx2opp[idx])) {
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pr_err("db8500-cpufreq: Failed to set OPP level\n");
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return -EINVAL;
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}
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/* post change notification */
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for_each_cpu(freqs.cpu, policy->cpus)
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cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
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return 0;
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}
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static unsigned int db8500_cpufreq_getspeed(unsigned int cpu)
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{
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int i;
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/* request the prcm to get the current ARM opp */
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for (i = 0; prcmu_get_arm_opp() != idx2opp[i]; i++)
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;
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return freq_table[i].frequency;
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}
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static int __cpuinit db8500_cpufreq_init(struct cpufreq_policy *policy)
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{
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int i, res;
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BUILD_BUG_ON(ARRAY_SIZE(idx2opp) + 1 != ARRAY_SIZE(freq_table));
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if (prcmu_has_arm_maxopp())
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freq_table[3].frequency = 1000000;
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pr_info("db8500-cpufreq : Available frequencies:\n");
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for (i = 0; freq_table[i].frequency != CPUFREQ_TABLE_END; i++)
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pr_info(" %d Mhz\n", freq_table[i].frequency/1000);
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/* get policy fields based on the table */
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res = cpufreq_frequency_table_cpuinfo(policy, freq_table);
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if (!res)
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cpufreq_frequency_table_get_attr(freq_table, policy->cpu);
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else {
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pr_err("db8500-cpufreq : Failed to read policy table\n");
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return res;
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}
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policy->min = policy->cpuinfo.min_freq;
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policy->max = policy->cpuinfo.max_freq;
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policy->cur = db8500_cpufreq_getspeed(policy->cpu);
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policy->governor = CPUFREQ_DEFAULT_GOVERNOR;
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/*
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* FIXME : Need to take time measurement across the target()
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* function with no/some/all drivers in the notification
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* list.
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*/
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policy->cpuinfo.transition_latency = 20 * 1000; /* in ns */
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/* policy sharing between dual CPUs */
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cpumask_copy(policy->cpus, cpu_present_mask);
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policy->shared_type = CPUFREQ_SHARED_TYPE_ALL;
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return 0;
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}
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static struct cpufreq_driver db8500_cpufreq_driver = {
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.flags = CPUFREQ_STICKY,
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.verify = db8500_cpufreq_verify_speed,
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.target = db8500_cpufreq_target,
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.get = db8500_cpufreq_getspeed,
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.init = db8500_cpufreq_init,
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.name = "DB8500",
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.attr = db8500_cpufreq_attr,
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};
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static int __init db8500_cpufreq_register(void)
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{
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if (!cpu_is_u8500_family())
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return -ENODEV;
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pr_info("cpufreq for DB8500 started\n");
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return cpufreq_register_driver(&db8500_cpufreq_driver);
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}
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device_initcall(db8500_cpufreq_register);
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