022ac03b45
Sometimes, bootloaders starts up with a frequency which is not in the OPP table. At cpu_init, policy->cur contains the frequency we pick at boot. It is possible that system might have fixed it's boot frequency later on as part of power initialization. After this condition, the first call to omap_target results in the following: omap_getspeed(actual device frequency) != policy->cur(frequency that cpufreq thinks that the system is at), and it is possible that freqs.old == freqs.new (because the governor requested a scale down). We exit without triggering the notifiers in the current code, which does'nt let code which depends on cpufreq_notify_transition to have accurate information as to what the system frequency is. Instead, we do a normal transition if policy->cur is wrong, then, freqs.old will be the actual cpu frequency, freqs.new will be the actual new cpu frequency and all required notifiers have the accurate information. Acked-by: Nishanth Menon <nm@ti.com> Signed-off-by: Colin Cross <ccross@google.com> Signed-off-by: Kevin Hilman <khilman@ti.com>
248 lines
6.1 KiB
C
248 lines
6.1 KiB
C
/*
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* CPU frequency scaling for OMAP
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*
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* Copyright (C) 2005 Nokia Corporation
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* Written by Tony Lindgren <tony@atomide.com>
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*
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* Based on cpu-sa1110.c, Copyright (C) 2001 Russell King
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*
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* Copyright (C) 2007-2011 Texas Instruments, Inc.
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* - OMAP3/4 support by Rajendra Nayak, Santosh Shilimkar
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#include <linux/types.h>
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#include <linux/kernel.h>
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#include <linux/sched.h>
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#include <linux/cpufreq.h>
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#include <linux/delay.h>
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#include <linux/init.h>
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#include <linux/err.h>
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#include <linux/clk.h>
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#include <linux/io.h>
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#include <linux/opp.h>
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#include <linux/cpu.h>
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#include <asm/system.h>
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#include <asm/smp_plat.h>
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#include <asm/cpu.h>
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#include <plat/clock.h>
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#include <plat/omap-pm.h>
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#include <plat/common.h>
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#include <mach/hardware.h>
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#define VERY_HI_RATE 900000000
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#ifdef CONFIG_SMP
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struct lpj_info {
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unsigned long ref;
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unsigned int freq;
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};
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static DEFINE_PER_CPU(struct lpj_info, lpj_ref);
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static struct lpj_info global_lpj_ref;
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#endif
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static struct cpufreq_frequency_table *freq_table;
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static struct clk *mpu_clk;
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static int omap_verify_speed(struct cpufreq_policy *policy)
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{
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if (freq_table)
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return cpufreq_frequency_table_verify(policy, freq_table);
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if (policy->cpu)
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return -EINVAL;
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cpufreq_verify_within_limits(policy, policy->cpuinfo.min_freq,
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policy->cpuinfo.max_freq);
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policy->min = clk_round_rate(mpu_clk, policy->min * 1000) / 1000;
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policy->max = clk_round_rate(mpu_clk, policy->max * 1000) / 1000;
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cpufreq_verify_within_limits(policy, policy->cpuinfo.min_freq,
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policy->cpuinfo.max_freq);
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return 0;
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}
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static unsigned int omap_getspeed(unsigned int cpu)
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{
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unsigned long rate;
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if (cpu >= NR_CPUS)
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return 0;
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rate = clk_get_rate(mpu_clk) / 1000;
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return rate;
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}
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static int omap_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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int i, ret = 0;
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struct cpufreq_freqs freqs;
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/* Ensure desired rate is within allowed range. Some govenors
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* (ondemand) will just pass target_freq=0 to get the minimum. */
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if (target_freq < policy->min)
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target_freq = policy->min;
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if (target_freq > policy->max)
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target_freq = policy->max;
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freqs.old = omap_getspeed(policy->cpu);
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freqs.new = clk_round_rate(mpu_clk, target_freq * 1000) / 1000;
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freqs.cpu = policy->cpu;
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if (freqs.old == freqs.new && policy->cur == freqs.new)
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return ret;
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/* notifiers */
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for_each_cpu(i, policy->cpus) {
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freqs.cpu = i;
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cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
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}
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#ifdef CONFIG_CPU_FREQ_DEBUG
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pr_info("cpufreq-omap: transition: %u --> %u\n", freqs.old, freqs.new);
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#endif
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ret = clk_set_rate(mpu_clk, freqs.new * 1000);
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freqs.new = omap_getspeed(policy->cpu);
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#ifdef CONFIG_SMP
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/*
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* Note that loops_per_jiffy is not updated on SMP systems in
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* cpufreq driver. So, update the per-CPU loops_per_jiffy value
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* on frequency transition. We need to update all dependent CPUs.
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*/
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for_each_cpu(i, policy->cpus) {
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struct lpj_info *lpj = &per_cpu(lpj_ref, i);
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if (!lpj->freq) {
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lpj->ref = per_cpu(cpu_data, i).loops_per_jiffy;
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lpj->freq = freqs.old;
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}
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per_cpu(cpu_data, i).loops_per_jiffy =
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cpufreq_scale(lpj->ref, lpj->freq, freqs.new);
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}
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/* And don't forget to adjust the global one */
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if (!global_lpj_ref.freq) {
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global_lpj_ref.ref = loops_per_jiffy;
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global_lpj_ref.freq = freqs.old;
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}
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loops_per_jiffy = cpufreq_scale(global_lpj_ref.ref, global_lpj_ref.freq,
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freqs.new);
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#endif
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/* notifiers */
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for_each_cpu(i, policy->cpus) {
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freqs.cpu = i;
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cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
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}
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return ret;
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}
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static int __cpuinit omap_cpu_init(struct cpufreq_policy *policy)
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{
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int result = 0;
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struct device *mpu_dev;
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if (cpu_is_omap24xx())
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mpu_clk = clk_get(NULL, "virt_prcm_set");
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else if (cpu_is_omap34xx())
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mpu_clk = clk_get(NULL, "dpll1_ck");
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else if (cpu_is_omap44xx())
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mpu_clk = clk_get(NULL, "dpll_mpu_ck");
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if (IS_ERR(mpu_clk))
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return PTR_ERR(mpu_clk);
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if (policy->cpu >= NR_CPUS)
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return -EINVAL;
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policy->cur = policy->min = policy->max = omap_getspeed(policy->cpu);
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mpu_dev = omap2_get_mpuss_device();
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if (!mpu_dev) {
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pr_warning("%s: unable to get the mpu device\n", __func__);
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return -EINVAL;
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}
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opp_init_cpufreq_table(mpu_dev, &freq_table);
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if (freq_table) {
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result = cpufreq_frequency_table_cpuinfo(policy, freq_table);
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if (!result)
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cpufreq_frequency_table_get_attr(freq_table,
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policy->cpu);
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} else {
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policy->cpuinfo.min_freq = clk_round_rate(mpu_clk, 0) / 1000;
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policy->cpuinfo.max_freq = clk_round_rate(mpu_clk,
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VERY_HI_RATE) / 1000;
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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 = omap_getspeed(policy->cpu);
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/*
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* On OMAP SMP configuartion, both processors share the voltage
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* and clock. So both CPUs needs to be scaled together and hence
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* needs software co-ordination. Use cpufreq affected_cpus
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* interface to handle this scenario. Additional is_smp() check
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* is to keep SMP_ON_UP build working.
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*/
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if (is_smp()) {
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policy->shared_type = CPUFREQ_SHARED_TYPE_ANY;
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cpumask_setall(policy->cpus);
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}
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/* FIXME: what's the actual transition time? */
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policy->cpuinfo.transition_latency = 300 * 1000;
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return 0;
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}
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static int omap_cpu_exit(struct cpufreq_policy *policy)
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{
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clk_exit_cpufreq_table(&freq_table);
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clk_put(mpu_clk);
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return 0;
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}
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static struct freq_attr *omap_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 struct cpufreq_driver omap_driver = {
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.flags = CPUFREQ_STICKY,
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.verify = omap_verify_speed,
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.target = omap_target,
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.get = omap_getspeed,
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.init = omap_cpu_init,
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.exit = omap_cpu_exit,
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.name = "omap",
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.attr = omap_cpufreq_attr,
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};
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static int __init omap_cpufreq_init(void)
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{
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return cpufreq_register_driver(&omap_driver);
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}
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static void __exit omap_cpufreq_exit(void)
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{
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cpufreq_unregister_driver(&omap_driver);
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}
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MODULE_DESCRIPTION("cpufreq driver for OMAP SoCs");
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MODULE_LICENSE("GPL");
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module_init(omap_cpufreq_init);
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module_exit(omap_cpufreq_exit);
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