/* * S3C2416/2450 CPUfreq Support * * Copyright 2011 Heiko Stuebner <heiko@sntech.de> * * based on s3c64xx_cpufreq.c * * Copyright 2009 Wolfson Microelectronics plc * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 as * published by the Free Software Foundation. */ #include <linux/kernel.h> #include <linux/types.h> #include <linux/init.h> #include <linux/cpufreq.h> #include <linux/clk.h> #include <linux/err.h> #include <linux/regulator/consumer.h> #include <linux/reboot.h> #include <linux/module.h> static DEFINE_MUTEX(cpufreq_lock); struct s3c2416_data { struct clk *armdiv; struct clk *armclk; struct clk *hclk; unsigned long regulator_latency; #ifdef CONFIG_ARM_S3C2416_CPUFREQ_VCORESCALE struct regulator *vddarm; #endif struct cpufreq_frequency_table *freq_table; bool is_dvs; bool disable_dvs; }; static struct s3c2416_data s3c2416_cpufreq; struct s3c2416_dvfs { unsigned int vddarm_min; unsigned int vddarm_max; }; /* pseudo-frequency for dvs mode */ #define FREQ_DVS 132333 /* frequency to sleep and reboot in * it's essential to leave dvs, as some boards do not reconfigure the * regulator on reboot */ #define FREQ_SLEEP 133333 /* Sources for the ARMCLK */ #define SOURCE_HCLK 0 #define SOURCE_ARMDIV 1 #ifdef CONFIG_ARM_S3C2416_CPUFREQ_VCORESCALE /* S3C2416 only supports changing the voltage in the dvs-mode. * Voltages down to 1.0V seem to work, so we take what the regulator * can get us. */ static struct s3c2416_dvfs s3c2416_dvfs_table[] = { [SOURCE_HCLK] = { 950000, 1250000 }, [SOURCE_ARMDIV] = { 1250000, 1350000 }, }; #endif static struct cpufreq_frequency_table s3c2416_freq_table[] = { { 0, SOURCE_HCLK, FREQ_DVS }, { 0, SOURCE_ARMDIV, 133333 }, { 0, SOURCE_ARMDIV, 266666 }, { 0, SOURCE_ARMDIV, 400000 }, { 0, 0, CPUFREQ_TABLE_END }, }; static struct cpufreq_frequency_table s3c2450_freq_table[] = { { 0, SOURCE_HCLK, FREQ_DVS }, { 0, SOURCE_ARMDIV, 133500 }, { 0, SOURCE_ARMDIV, 267000 }, { 0, SOURCE_ARMDIV, 534000 }, { 0, 0, CPUFREQ_TABLE_END }, }; static unsigned int s3c2416_cpufreq_get_speed(unsigned int cpu) { struct s3c2416_data *s3c_freq = &s3c2416_cpufreq; if (cpu != 0) return 0; /* return our pseudo-frequency when in dvs mode */ if (s3c_freq->is_dvs) return FREQ_DVS; return clk_get_rate(s3c_freq->armclk) / 1000; } static int s3c2416_cpufreq_set_armdiv(struct s3c2416_data *s3c_freq, unsigned int freq) { int ret; if (clk_get_rate(s3c_freq->armdiv) / 1000 != freq) { ret = clk_set_rate(s3c_freq->armdiv, freq * 1000); if (ret < 0) { pr_err("cpufreq: Failed to set armdiv rate %dkHz: %d\n", freq, ret); return ret; } } return 0; } static int s3c2416_cpufreq_enter_dvs(struct s3c2416_data *s3c_freq, int idx) { #ifdef CONFIG_ARM_S3C2416_CPUFREQ_VCORESCALE struct s3c2416_dvfs *dvfs; #endif int ret; if (s3c_freq->is_dvs) { pr_debug("cpufreq: already in dvs mode, nothing to do\n"); return 0; } pr_debug("cpufreq: switching armclk to hclk (%lukHz)\n", clk_get_rate(s3c_freq->hclk) / 1000); ret = clk_set_parent(s3c_freq->armclk, s3c_freq->hclk); if (ret < 0) { pr_err("cpufreq: Failed to switch armclk to hclk: %d\n", ret); return ret; } #ifdef CONFIG_ARM_S3C2416_CPUFREQ_VCORESCALE /* changing the core voltage is only allowed when in dvs mode */ if (s3c_freq->vddarm) { dvfs = &s3c2416_dvfs_table[idx]; pr_debug("cpufreq: setting regulator to %d-%d\n", dvfs->vddarm_min, dvfs->vddarm_max); ret = regulator_set_voltage(s3c_freq->vddarm, dvfs->vddarm_min, dvfs->vddarm_max); /* when lowering the voltage failed, there is nothing to do */ if (ret != 0) pr_err("cpufreq: Failed to set VDDARM: %d\n", ret); } #endif s3c_freq->is_dvs = 1; return 0; } static int s3c2416_cpufreq_leave_dvs(struct s3c2416_data *s3c_freq, int idx) { #ifdef CONFIG_ARM_S3C2416_CPUFREQ_VCORESCALE struct s3c2416_dvfs *dvfs; #endif int ret; if (!s3c_freq->is_dvs) { pr_debug("cpufreq: not in dvs mode, so can't leave\n"); return 0; } #ifdef CONFIG_ARM_S3C2416_CPUFREQ_VCORESCALE if (s3c_freq->vddarm) { dvfs = &s3c2416_dvfs_table[idx]; pr_debug("cpufreq: setting regulator to %d-%d\n", dvfs->vddarm_min, dvfs->vddarm_max); ret = regulator_set_voltage(s3c_freq->vddarm, dvfs->vddarm_min, dvfs->vddarm_max); if (ret != 0) { pr_err("cpufreq: Failed to set VDDARM: %d\n", ret); return ret; } } #endif /* force armdiv to hclk frequency for transition from dvs*/ if (clk_get_rate(s3c_freq->armdiv) > clk_get_rate(s3c_freq->hclk)) { pr_debug("cpufreq: force armdiv to hclk frequency (%lukHz)\n", clk_get_rate(s3c_freq->hclk) / 1000); ret = s3c2416_cpufreq_set_armdiv(s3c_freq, clk_get_rate(s3c_freq->hclk) / 1000); if (ret < 0) { pr_err("cpufreq: Failed to set the armdiv to %lukHz: %d\n", clk_get_rate(s3c_freq->hclk) / 1000, ret); return ret; } } pr_debug("cpufreq: switching armclk parent to armdiv (%lukHz)\n", clk_get_rate(s3c_freq->armdiv) / 1000); ret = clk_set_parent(s3c_freq->armclk, s3c_freq->armdiv); if (ret < 0) { pr_err("cpufreq: Failed to switch armclk clock parent to armdiv: %d\n", ret); return ret; } s3c_freq->is_dvs = 0; return 0; } static int s3c2416_cpufreq_set_target(struct cpufreq_policy *policy, unsigned int index) { struct s3c2416_data *s3c_freq = &s3c2416_cpufreq; unsigned int new_freq; int idx, ret, to_dvs = 0; mutex_lock(&cpufreq_lock); idx = s3c_freq->freq_table[index].driver_data; if (idx == SOURCE_HCLK) to_dvs = 1; /* switching to dvs when it's not allowed */ if (to_dvs && s3c_freq->disable_dvs) { pr_debug("cpufreq: entering dvs mode not allowed\n"); ret = -EINVAL; goto out; } /* When leavin dvs mode, always switch the armdiv to the hclk rate * The S3C2416 has stability issues when switching directly to * higher frequencies. */ new_freq = (s3c_freq->is_dvs && !to_dvs) ? clk_get_rate(s3c_freq->hclk) / 1000 : s3c_freq->freq_table[index].frequency; if (to_dvs) { pr_debug("cpufreq: enter dvs\n"); ret = s3c2416_cpufreq_enter_dvs(s3c_freq, idx); } else if (s3c_freq->is_dvs) { pr_debug("cpufreq: leave dvs\n"); ret = s3c2416_cpufreq_leave_dvs(s3c_freq, idx); } else { pr_debug("cpufreq: change armdiv to %dkHz\n", new_freq); ret = s3c2416_cpufreq_set_armdiv(s3c_freq, new_freq); } out: mutex_unlock(&cpufreq_lock); return ret; } #ifdef CONFIG_ARM_S3C2416_CPUFREQ_VCORESCALE static void s3c2416_cpufreq_cfg_regulator(struct s3c2416_data *s3c_freq) { int count, v, i, found; struct cpufreq_frequency_table *pos; struct s3c2416_dvfs *dvfs; count = regulator_count_voltages(s3c_freq->vddarm); if (count < 0) { pr_err("cpufreq: Unable to check supported voltages\n"); return; } if (!count) goto out; cpufreq_for_each_valid_entry(pos, s3c_freq->freq_table) { dvfs = &s3c2416_dvfs_table[pos->driver_data]; found = 0; /* Check only the min-voltage, more is always ok on S3C2416 */ for (i = 0; i < count; i++) { v = regulator_list_voltage(s3c_freq->vddarm, i); if (v >= dvfs->vddarm_min) found = 1; } if (!found) { pr_debug("cpufreq: %dkHz unsupported by regulator\n", pos->frequency); pos->frequency = CPUFREQ_ENTRY_INVALID; } } out: /* Guessed */ s3c_freq->regulator_latency = 1 * 1000 * 1000; } #endif static int s3c2416_cpufreq_reboot_notifier_evt(struct notifier_block *this, unsigned long event, void *ptr) { struct s3c2416_data *s3c_freq = &s3c2416_cpufreq; int ret; mutex_lock(&cpufreq_lock); /* disable further changes */ s3c_freq->disable_dvs = 1; mutex_unlock(&cpufreq_lock); /* some boards don't reconfigure the regulator on reboot, which * could lead to undervolting the cpu when the clock is reset. * Therefore we always leave the DVS mode on reboot. */ if (s3c_freq->is_dvs) { pr_debug("cpufreq: leave dvs on reboot\n"); ret = cpufreq_driver_target(cpufreq_cpu_get(0), FREQ_SLEEP, 0); if (ret < 0) return NOTIFY_BAD; } return NOTIFY_DONE; } static struct notifier_block s3c2416_cpufreq_reboot_notifier = { .notifier_call = s3c2416_cpufreq_reboot_notifier_evt, }; static int s3c2416_cpufreq_driver_init(struct cpufreq_policy *policy) { struct s3c2416_data *s3c_freq = &s3c2416_cpufreq; struct cpufreq_frequency_table *pos; struct clk *msysclk; unsigned long rate; int ret; if (policy->cpu != 0) return -EINVAL; msysclk = clk_get(NULL, "msysclk"); if (IS_ERR(msysclk)) { ret = PTR_ERR(msysclk); pr_err("cpufreq: Unable to obtain msysclk: %d\n", ret); return ret; } /* * S3C2416 and S3C2450 share the same processor-ID and also provide no * other means to distinguish them other than through the rate of * msysclk. On S3C2416 msysclk runs at 800MHz and on S3C2450 at 533MHz. */ rate = clk_get_rate(msysclk); if (rate == 800 * 1000 * 1000) { pr_info("cpufreq: msysclk running at %lukHz, using S3C2416 frequency table\n", rate / 1000); s3c_freq->freq_table = s3c2416_freq_table; policy->cpuinfo.max_freq = 400000; } else if (rate / 1000 == 534000) { pr_info("cpufreq: msysclk running at %lukHz, using S3C2450 frequency table\n", rate / 1000); s3c_freq->freq_table = s3c2450_freq_table; policy->cpuinfo.max_freq = 534000; } /* not needed anymore */ clk_put(msysclk); if (s3c_freq->freq_table == NULL) { pr_err("cpufreq: No frequency information for this CPU, msysclk at %lukHz\n", rate / 1000); return -ENODEV; } s3c_freq->is_dvs = 0; s3c_freq->armdiv = clk_get(NULL, "armdiv"); if (IS_ERR(s3c_freq->armdiv)) { ret = PTR_ERR(s3c_freq->armdiv); pr_err("cpufreq: Unable to obtain ARMDIV: %d\n", ret); return ret; } s3c_freq->hclk = clk_get(NULL, "hclk"); if (IS_ERR(s3c_freq->hclk)) { ret = PTR_ERR(s3c_freq->hclk); pr_err("cpufreq: Unable to obtain HCLK: %d\n", ret); goto err_hclk; } /* chech hclk rate, we only support the common 133MHz for now * hclk could also run at 66MHz, but this not often used */ rate = clk_get_rate(s3c_freq->hclk); if (rate < 133 * 1000 * 1000) { pr_err("cpufreq: HCLK not at 133MHz\n"); clk_put(s3c_freq->hclk); ret = -EINVAL; goto err_armclk; } s3c_freq->armclk = clk_get(NULL, "armclk"); if (IS_ERR(s3c_freq->armclk)) { ret = PTR_ERR(s3c_freq->armclk); pr_err("cpufreq: Unable to obtain ARMCLK: %d\n", ret); goto err_armclk; } #ifdef CONFIG_ARM_S3C2416_CPUFREQ_VCORESCALE s3c_freq->vddarm = regulator_get(NULL, "vddarm"); if (IS_ERR(s3c_freq->vddarm)) { ret = PTR_ERR(s3c_freq->vddarm); pr_err("cpufreq: Failed to obtain VDDARM: %d\n", ret); goto err_vddarm; } s3c2416_cpufreq_cfg_regulator(s3c_freq); #else s3c_freq->regulator_latency = 0; #endif cpufreq_for_each_entry(pos, s3c_freq->freq_table) { /* special handling for dvs mode */ if (pos->driver_data == 0) { if (!s3c_freq->hclk) { pr_debug("cpufreq: %dkHz unsupported as it would need unavailable dvs mode\n", pos->frequency); pos->frequency = CPUFREQ_ENTRY_INVALID; } else { continue; } } /* Check for frequencies we can generate */ rate = clk_round_rate(s3c_freq->armdiv, pos->frequency * 1000); rate /= 1000; if (rate != pos->frequency) { pr_debug("cpufreq: %dkHz unsupported by clock (clk_round_rate return %lu)\n", pos->frequency, rate); pos->frequency = CPUFREQ_ENTRY_INVALID; } } /* Datasheet says PLL stabalisation time must be at least 300us, * so but add some fudge. (reference in LOCKCON0 register description) */ ret = cpufreq_generic_init(policy, s3c_freq->freq_table, (500 * 1000) + s3c_freq->regulator_latency); if (ret) goto err_freq_table; register_reboot_notifier(&s3c2416_cpufreq_reboot_notifier); return 0; err_freq_table: #ifdef CONFIG_ARM_S3C2416_CPUFREQ_VCORESCALE regulator_put(s3c_freq->vddarm); err_vddarm: #endif clk_put(s3c_freq->armclk); err_armclk: clk_put(s3c_freq->hclk); err_hclk: clk_put(s3c_freq->armdiv); return ret; } static struct cpufreq_driver s3c2416_cpufreq_driver = { .flags = CPUFREQ_NEED_INITIAL_FREQ_CHECK, .verify = cpufreq_generic_frequency_table_verify, .target_index = s3c2416_cpufreq_set_target, .get = s3c2416_cpufreq_get_speed, .init = s3c2416_cpufreq_driver_init, .name = "s3c2416", .attr = cpufreq_generic_attr, }; static int __init s3c2416_cpufreq_init(void) { return cpufreq_register_driver(&s3c2416_cpufreq_driver); } module_init(s3c2416_cpufreq_init);