1/* us3_cpufreq.c: UltraSPARC-III cpu frequency support 2 * 3 * Copyright (C) 2003 David S. Miller (davem@redhat.com) 4 * 5 * Many thanks to Dominik Brodowski for fixing up the cpufreq 6 * infrastructure in order to make this driver easier to implement. 7 */ 8 9#include <linux/kernel.h> 10#include <linux/module.h> 11#include <linux/sched.h> 12#include <linux/smp.h> 13#include <linux/cpufreq.h> 14#include <linux/threads.h> 15#include <linux/slab.h> 16#include <linux/init.h> 17 18#include <asm/head.h> 19#include <asm/timer.h> 20 21static struct cpufreq_driver *cpufreq_us3_driver; 22 23struct us3_freq_percpu_info { 24 struct cpufreq_frequency_table table[4]; 25}; 26 27/* Indexed by cpu number. */ 28static struct us3_freq_percpu_info *us3_freq_table; 29 30/* UltraSPARC-III has three dividers: 1, 2, and 32. These are controlled 31 * in the Safari config register. 32 */ 33#define SAFARI_CFG_DIV_1 0x0000000000000000UL 34#define SAFARI_CFG_DIV_2 0x0000000040000000UL 35#define SAFARI_CFG_DIV_32 0x0000000080000000UL 36#define SAFARI_CFG_DIV_MASK 0x00000000C0000000UL 37 38static unsigned long read_safari_cfg(void) 39{ 40 unsigned long ret; 41 42 __asm__ __volatile__("ldxa [%%g0] %1, %0" 43 : "=&r" (ret) 44 : "i" (ASI_SAFARI_CONFIG)); 45 return ret; 46} 47 48static void write_safari_cfg(unsigned long val) 49{ 50 __asm__ __volatile__("stxa %0, [%%g0] %1\n\t" 51 "membar #Sync" 52 : /* no outputs */ 53 : "r" (val), "i" (ASI_SAFARI_CONFIG) 54 : "memory"); 55} 56 57static unsigned long get_current_freq(unsigned int cpu, unsigned long safari_cfg) 58{ 59 unsigned long clock_tick = sparc64_get_clock_tick(cpu) / 1000; 60 unsigned long ret; 61 62 switch (safari_cfg & SAFARI_CFG_DIV_MASK) { 63 case SAFARI_CFG_DIV_1: 64 ret = clock_tick / 1; 65 break; 66 case SAFARI_CFG_DIV_2: 67 ret = clock_tick / 2; 68 break; 69 case SAFARI_CFG_DIV_32: 70 ret = clock_tick / 32; 71 break; 72 default: 73 BUG(); 74 }; 75 76 return ret; 77} 78 79static unsigned int us3_freq_get(unsigned int cpu) 80{ 81 cpumask_t cpus_allowed; 82 unsigned long reg; 83 unsigned int ret; 84 85 if (!cpu_online(cpu)) 86 return 0; 87 88 cpus_allowed = current->cpus_allowed; 89 set_cpus_allowed_ptr(current, cpumask_of(cpu)); 90 91 reg = read_safari_cfg(); 92 ret = get_current_freq(cpu, reg); 93 94 set_cpus_allowed_ptr(current, &cpus_allowed); 95 96 return ret; 97} 98 99static void us3_set_cpu_divider_index(unsigned int cpu, unsigned int index) 100{ 101 unsigned long new_bits, new_freq, reg; 102 cpumask_t cpus_allowed; 103 struct cpufreq_freqs freqs; 104 105 if (!cpu_online(cpu)) 106 return; 107 108 cpus_allowed = current->cpus_allowed; 109 set_cpus_allowed_ptr(current, cpumask_of(cpu)); 110 111 new_freq = sparc64_get_clock_tick(cpu) / 1000; 112 switch (index) { 113 case 0: 114 new_bits = SAFARI_CFG_DIV_1; 115 new_freq /= 1; 116 break; 117 case 1: 118 new_bits = SAFARI_CFG_DIV_2; 119 new_freq /= 2; 120 break; 121 case 2: 122 new_bits = SAFARI_CFG_DIV_32; 123 new_freq /= 32; 124 break; 125 126 default: 127 BUG(); 128 }; 129 130 reg = read_safari_cfg(); 131 132 freqs.old = get_current_freq(cpu, reg); 133 freqs.new = new_freq; 134 freqs.cpu = cpu; 135 cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE); 136 137 reg &= ~SAFARI_CFG_DIV_MASK; 138 reg |= new_bits; 139 write_safari_cfg(reg); 140 141 cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE); 142 143 set_cpus_allowed_ptr(current, &cpus_allowed); 144} 145 146static int us3_freq_target(struct cpufreq_policy *policy, 147 unsigned int target_freq, 148 unsigned int relation) 149{ 150 unsigned int new_index = 0; 151 152 if (cpufreq_frequency_table_target(policy, 153 &us3_freq_table[policy->cpu].table[0], 154 target_freq, 155 relation, 156 &new_index)) 157 return -EINVAL; 158 159 us3_set_cpu_divider_index(policy->cpu, new_index); 160 161 return 0; 162} 163 164static int us3_freq_verify(struct cpufreq_policy *policy) 165{ 166 return cpufreq_frequency_table_verify(policy, 167 &us3_freq_table[policy->cpu].table[0]); 168} 169 170static int __init us3_freq_cpu_init(struct cpufreq_policy *policy) 171{ 172 unsigned int cpu = policy->cpu; 173 unsigned long clock_tick = sparc64_get_clock_tick(cpu) / 1000; 174 struct cpufreq_frequency_table *table = 175 &us3_freq_table[cpu].table[0]; 176 177 table[0].index = 0; 178 table[0].frequency = clock_tick / 1; 179 table[1].index = 1; 180 table[1].frequency = clock_tick / 2; 181 table[2].index = 2; 182 table[2].frequency = clock_tick / 32; 183 table[3].index = 0; 184 table[3].frequency = CPUFREQ_TABLE_END; 185 186 policy->cpuinfo.transition_latency = 0; 187 policy->cur = clock_tick; 188 189 return cpufreq_frequency_table_cpuinfo(policy, table); 190} 191 192static int us3_freq_cpu_exit(struct cpufreq_policy *policy) 193{ 194 if (cpufreq_us3_driver) 195 us3_set_cpu_divider_index(policy->cpu, 0); 196 197 return 0; 198} 199 200static int __init us3_freq_init(void) 201{ 202 unsigned long manuf, impl, ver; 203 int ret; 204 205 if (tlb_type != cheetah && tlb_type != cheetah_plus) 206 return -ENODEV; 207 208 __asm__("rdpr %%ver, %0" : "=r" (ver)); 209 manuf = ((ver >> 48) & 0xffff); 210 impl = ((ver >> 32) & 0xffff); 211 212 if (manuf == CHEETAH_MANUF && 213 (impl == CHEETAH_IMPL || 214 impl == CHEETAH_PLUS_IMPL || 215 impl == JAGUAR_IMPL || 216 impl == PANTHER_IMPL)) { 217 struct cpufreq_driver *driver; 218 219 ret = -ENOMEM; 220 driver = kzalloc(sizeof(struct cpufreq_driver), GFP_KERNEL); 221 if (!driver) 222 goto err_out; 223 224 us3_freq_table = kzalloc( 225 (NR_CPUS * sizeof(struct us3_freq_percpu_info)), 226 GFP_KERNEL); 227 if (!us3_freq_table) 228 goto err_out; 229 230 driver->init = us3_freq_cpu_init; 231 driver->verify = us3_freq_verify; 232 driver->target = us3_freq_target; 233 driver->get = us3_freq_get; 234 driver->exit = us3_freq_cpu_exit; 235 driver->owner = THIS_MODULE, 236 strcpy(driver->name, "UltraSPARC-III"); 237 238 cpufreq_us3_driver = driver; 239 ret = cpufreq_register_driver(driver); 240 if (ret) 241 goto err_out; 242 243 return 0; 244 245err_out: 246 if (driver) { 247 kfree(driver); 248 cpufreq_us3_driver = NULL; 249 } 250 kfree(us3_freq_table); 251 us3_freq_table = NULL; 252 return ret; 253 } 254 255 return -ENODEV; 256} 257 258static void __exit us3_freq_exit(void) 259{ 260 if (cpufreq_us3_driver) { 261 cpufreq_unregister_driver(cpufreq_us3_driver); 262 kfree(cpufreq_us3_driver); 263 cpufreq_us3_driver = NULL; 264 kfree(us3_freq_table); 265 us3_freq_table = NULL; 266 } 267} 268 269MODULE_AUTHOR("David S. Miller <davem@redhat.com>"); 270MODULE_DESCRIPTION("cpufreq driver for UltraSPARC-III"); 271MODULE_LICENSE("GPL"); 272 273module_init(us3_freq_init); 274module_exit(us3_freq_exit); 275