Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
| 2 | * arch/sh/kernel/cpufreq.c |
| 3 | * |
| 4 | * cpufreq driver for the SuperH processors. |
| 5 | * |
| 6 | * Copyright (C) 2002, 2003, 2004, 2005 Paul Mundt |
| 7 | * Copyright (C) 2002 M. R. Brown |
| 8 | * |
| 9 | * This program is free software; you can redistribute it and/or modify it |
| 10 | * under the terms of the GNU General Public License as published by the |
| 11 | * Free Software Foundation; either version 2 of the License, or (at your |
| 12 | * option) any later version. |
| 13 | */ |
| 14 | #include <linux/types.h> |
| 15 | #include <linux/cpufreq.h> |
| 16 | #include <linux/kernel.h> |
| 17 | #include <linux/module.h> |
| 18 | #include <linux/slab.h> |
| 19 | #include <linux/init.h> |
| 20 | #include <linux/delay.h> |
| 21 | #include <linux/cpumask.h> |
| 22 | #include <linux/smp.h> |
| 23 | |
| 24 | #include <asm/processor.h> |
| 25 | #include <asm/watchdog.h> |
| 26 | #include <asm/freq.h> |
| 27 | #include <asm/io.h> |
| 28 | |
| 29 | /* |
| 30 | * For SuperH, each policy change requires that we change the IFC, BFC, and |
| 31 | * PFC at the same time. Here we define sane values that won't trash the |
| 32 | * system. |
| 33 | * |
| 34 | * Note the max set is computed at runtime, we use the divisors that we booted |
| 35 | * with to setup our maximum operating frequencies. |
| 36 | */ |
| 37 | struct clock_set { |
| 38 | unsigned int ifc; |
| 39 | unsigned int bfc; |
| 40 | unsigned int pfc; |
| 41 | } clock_sets[] = { |
| 42 | #if defined(CONFIG_CPU_SH3) || defined(CONFIG_CPU_SH2) |
| 43 | { 0, 0, 0 }, /* not implemented yet */ |
| 44 | #elif defined(CONFIG_CPU_SH4) |
| 45 | { 4, 8, 8 }, /* min - IFC: 1/4, BFC: 1/8, PFC: 1/8 */ |
| 46 | { 1, 2, 2 }, /* max - IFC: 1, BFC: 1/2, PFC: 1/2 */ |
| 47 | #endif |
| 48 | }; |
| 49 | |
| 50 | #define MIN_CLOCK_SET 0 |
| 51 | #define MAX_CLOCK_SET (ARRAY_SIZE(clock_sets) - 1) |
| 52 | |
| 53 | /* |
| 54 | * For the time being, we only support two frequencies, which in turn are |
| 55 | * aimed at the POWERSAVE and PERFORMANCE policies, which in turn are derived |
| 56 | * directly from the respective min/max clock sets. Technically we could |
| 57 | * support a wider range of frequencies, but these vary far too much for each |
| 58 | * CPU subtype (and we'd have to construct a frequency table for each subtype). |
| 59 | * |
| 60 | * Maybe something to implement in the future.. |
| 61 | */ |
| 62 | #define SH_FREQ_MAX 0 |
| 63 | #define SH_FREQ_MIN 1 |
| 64 | |
| 65 | static struct cpufreq_frequency_table sh_freqs[] = { |
| 66 | { SH_FREQ_MAX, 0 }, |
| 67 | { SH_FREQ_MIN, 0 }, |
| 68 | { 0, CPUFREQ_TABLE_END }, |
| 69 | }; |
| 70 | |
| 71 | static void sh_cpufreq_update_clocks(unsigned int set) |
| 72 | { |
| 73 | current_cpu_data.cpu_clock = current_cpu_data.master_clock / clock_sets[set].ifc; |
| 74 | current_cpu_data.bus_clock = current_cpu_data.master_clock / clock_sets[set].bfc; |
| 75 | current_cpu_data.module_clock = current_cpu_data.master_clock / clock_sets[set].pfc; |
| 76 | current_cpu_data.loops_per_jiffy = loops_per_jiffy; |
| 77 | } |
| 78 | |
| 79 | /* XXX: This needs to be split out per CPU and CPU subtype. */ |
| 80 | /* |
| 81 | * Here we notify other drivers of the proposed change and the final change. |
| 82 | */ |
| 83 | static int sh_cpufreq_setstate(unsigned int cpu, unsigned int set) |
| 84 | { |
| 85 | unsigned short frqcr = ctrl_inw(FRQCR); |
| 86 | cpumask_t cpus_allowed; |
| 87 | struct cpufreq_freqs freqs; |
| 88 | |
| 89 | if (!cpu_online(cpu)) |
| 90 | return -ENODEV; |
| 91 | |
| 92 | cpus_allowed = current->cpus_allowed; |
| 93 | set_cpus_allowed(current, cpumask_of_cpu(cpu)); |
| 94 | |
| 95 | BUG_ON(smp_processor_id() != cpu); |
| 96 | |
| 97 | freqs.cpu = cpu; |
| 98 | freqs.old = current_cpu_data.cpu_clock / 1000; |
| 99 | freqs.new = (current_cpu_data.master_clock / clock_sets[set].ifc) / 1000; |
| 100 | |
| 101 | cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE); |
| 102 | #if defined(CONFIG_CPU_SH3) |
| 103 | frqcr |= (newstate & 0x4000) << 14; |
| 104 | frqcr |= (newstate & 0x000c) << 2; |
| 105 | #elif defined(CONFIG_CPU_SH4) |
| 106 | /* |
| 107 | * FRQCR.PLL2EN is 1, we need to allow the PLL to stabilize by |
| 108 | * initializing the WDT. |
| 109 | */ |
| 110 | if (frqcr & (1 << 9)) { |
| 111 | __u8 csr; |
| 112 | |
| 113 | /* |
| 114 | * Set the overflow period to the highest available, |
| 115 | * in this case a 1/4096 division ratio yields a 5.25ms |
| 116 | * overflow period. See asm-sh/watchdog.h for more |
| 117 | * information and a range of other divisors. |
| 118 | */ |
| 119 | csr = sh_wdt_read_csr(); |
| 120 | csr |= WTCSR_CKS_4096; |
| 121 | sh_wdt_write_csr(csr); |
| 122 | |
| 123 | sh_wdt_write_cnt(0); |
| 124 | } |
| 125 | frqcr &= 0x0e00; /* Clear ifc, bfc, pfc */ |
| 126 | frqcr |= get_ifc_value(clock_sets[set].ifc) << 6; |
| 127 | frqcr |= get_bfc_value(clock_sets[set].bfc) << 3; |
| 128 | frqcr |= get_pfc_value(clock_sets[set].pfc); |
| 129 | #endif |
| 130 | ctrl_outw(frqcr, FRQCR); |
| 131 | sh_cpufreq_update_clocks(set); |
| 132 | |
| 133 | set_cpus_allowed(current, cpus_allowed); |
| 134 | cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE); |
| 135 | |
| 136 | return 0; |
| 137 | } |
| 138 | |
| 139 | static int sh_cpufreq_cpu_init(struct cpufreq_policy *policy) |
| 140 | { |
| 141 | unsigned int min_freq, max_freq; |
| 142 | unsigned int ifc, bfc, pfc; |
| 143 | |
| 144 | if (!cpu_online(policy->cpu)) |
| 145 | return -ENODEV; |
| 146 | |
| 147 | /* Update our maximum clock set */ |
| 148 | get_current_frequency_divisors(&ifc, &bfc, &pfc); |
| 149 | clock_sets[MAX_CLOCK_SET].ifc = ifc; |
| 150 | clock_sets[MAX_CLOCK_SET].bfc = bfc; |
| 151 | clock_sets[MAX_CLOCK_SET].pfc = pfc; |
| 152 | |
| 153 | /* Convert from Hz to kHz */ |
| 154 | max_freq = current_cpu_data.cpu_clock / 1000; |
| 155 | min_freq = (current_cpu_data.master_clock / clock_sets[MIN_CLOCK_SET].ifc) / 1000; |
| 156 | |
| 157 | sh_freqs[SH_FREQ_MAX].frequency = max_freq; |
| 158 | sh_freqs[SH_FREQ_MIN].frequency = min_freq; |
| 159 | |
| 160 | /* cpuinfo and default policy values */ |
| 161 | policy->governor = CPUFREQ_DEFAULT_GOVERNOR; |
| 162 | policy->cpuinfo.transition_latency = CPUFREQ_ETERNAL; |
| 163 | policy->cur = max_freq; |
| 164 | |
| 165 | return cpufreq_frequency_table_cpuinfo(policy, &sh_freqs[0]); |
| 166 | } |
| 167 | |
| 168 | static int sh_cpufreq_verify(struct cpufreq_policy *policy) |
| 169 | { |
| 170 | return cpufreq_frequency_table_verify(policy, &sh_freqs[0]); |
| 171 | } |
| 172 | |
| 173 | static int sh_cpufreq_target(struct cpufreq_policy *policy, |
| 174 | unsigned int target_freq, |
| 175 | unsigned int relation) |
| 176 | { |
| 177 | unsigned int set, idx = 0; |
| 178 | |
| 179 | if (cpufreq_frequency_table_target(policy, &sh_freqs[0], target_freq, relation, &idx)) |
| 180 | return -EINVAL; |
| 181 | |
| 182 | set = (idx == SH_FREQ_MIN) ? MIN_CLOCK_SET : MAX_CLOCK_SET; |
| 183 | |
| 184 | sh_cpufreq_setstate(policy->cpu, set); |
| 185 | |
| 186 | return 0; |
| 187 | } |
| 188 | |
| 189 | static struct cpufreq_driver sh_cpufreq_driver = { |
| 190 | .owner = THIS_MODULE, |
| 191 | .name = "SH cpufreq", |
| 192 | .init = sh_cpufreq_cpu_init, |
| 193 | .verify = sh_cpufreq_verify, |
| 194 | .target = sh_cpufreq_target, |
| 195 | }; |
| 196 | |
| 197 | static int __init sh_cpufreq_init(void) |
| 198 | { |
| 199 | if (!current_cpu_data.cpu_clock) |
| 200 | return -EINVAL; |
| 201 | if (cpufreq_register_driver(&sh_cpufreq_driver)) |
| 202 | return -EINVAL; |
| 203 | |
| 204 | return 0; |
| 205 | } |
| 206 | |
| 207 | static void __exit sh_cpufreq_exit(void) |
| 208 | { |
| 209 | cpufreq_unregister_driver(&sh_cpufreq_driver); |
| 210 | } |
| 211 | |
| 212 | module_init(sh_cpufreq_init); |
| 213 | module_exit(sh_cpufreq_exit); |
| 214 | |
| 215 | MODULE_AUTHOR("Paul Mundt <lethal@linux-sh.org>"); |
| 216 | MODULE_DESCRIPTION("cpufreq driver for SuperH"); |
| 217 | MODULE_LICENSE("GPL"); |
| 218 | |