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1// SPDX-License-Identifier: GPL-2.0-only2/* us3_cpufreq.c: UltraSPARC-III cpu frequency support3 *4 * Copyright (C) 2003 David S. Miller (davem@redhat.com)5 *6 * Many thanks to Dominik Brodowski for fixing up the cpufreq7 * infrastructure in order to make this driver easier to implement.8 */9 10#include <linux/kernel.h>11#include <linux/module.h>12#include <linux/sched.h>13#include <linux/smp.h>14#include <linux/cpufreq.h>15#include <linux/threads.h>16#include <linux/slab.h>17#include <linux/init.h>18 19#include <asm/head.h>20#include <asm/timer.h>21 22struct us3_freq_percpu_info {23 struct cpufreq_frequency_table table[4];24};25 26/* Indexed by cpu number. */27static struct us3_freq_percpu_info *us3_freq_table;28 29/* UltraSPARC-III has three dividers: 1, 2, and 32. These are controlled30 * in the Safari config register.31 */32#define SAFARI_CFG_DIV_1 0x0000000000000000UL33#define SAFARI_CFG_DIV_2 0x0000000040000000UL34#define SAFARI_CFG_DIV_32 0x0000000080000000UL35#define SAFARI_CFG_DIV_MASK 0x00000000C0000000UL36 37static void read_safari_cfg(void *arg)38{39 unsigned long ret, *val = arg;40 41 __asm__ __volatile__("ldxa [%%g0] %1, %0"42 : "=&r" (ret)43 : "i" (ASI_SAFARI_CONFIG));44 *val = ret;45}46 47static void update_safari_cfg(void *arg)48{49 unsigned long reg, *new_bits = arg;50 51 read_safari_cfg(®);52 reg &= ~SAFARI_CFG_DIV_MASK;53 reg |= *new_bits;54 55 __asm__ __volatile__("stxa %0, [%%g0] %1\n\t"56 "membar #Sync"57 : /* no outputs */58 : "r" (reg), "i" (ASI_SAFARI_CONFIG)59 : "memory");60}61 62static unsigned long get_current_freq(unsigned int cpu, unsigned long safari_cfg)63{64 unsigned long clock_tick = sparc64_get_clock_tick(cpu) / 1000;65 unsigned long ret;66 67 switch (safari_cfg & SAFARI_CFG_DIV_MASK) {68 case SAFARI_CFG_DIV_1:69 ret = clock_tick / 1;70 break;71 case SAFARI_CFG_DIV_2:72 ret = clock_tick / 2;73 break;74 case SAFARI_CFG_DIV_32:75 ret = clock_tick / 32;76 break;77 default:78 BUG();79 }80 81 return ret;82}83 84static unsigned int us3_freq_get(unsigned int cpu)85{86 unsigned long reg;87 88 if (smp_call_function_single(cpu, read_safari_cfg, ®, 1))89 return 0;90 return get_current_freq(cpu, reg);91}92 93static int us3_freq_target(struct cpufreq_policy *policy, unsigned int index)94{95 unsigned int cpu = policy->cpu;96 unsigned long new_bits, new_freq;97 98 new_freq = sparc64_get_clock_tick(cpu) / 1000;99 switch (index) {100 case 0:101 new_bits = SAFARI_CFG_DIV_1;102 new_freq /= 1;103 break;104 case 1:105 new_bits = SAFARI_CFG_DIV_2;106 new_freq /= 2;107 break;108 case 2:109 new_bits = SAFARI_CFG_DIV_32;110 new_freq /= 32;111 break;112 113 default:114 BUG();115 }116 117 return smp_call_function_single(cpu, update_safari_cfg, &new_bits, 1);118}119 120static int us3_freq_cpu_init(struct cpufreq_policy *policy)121{122 unsigned int cpu = policy->cpu;123 unsigned long clock_tick = sparc64_get_clock_tick(cpu) / 1000;124 struct cpufreq_frequency_table *table =125 &us3_freq_table[cpu].table[0];126 127 table[0].driver_data = 0;128 table[0].frequency = clock_tick / 1;129 table[1].driver_data = 1;130 table[1].frequency = clock_tick / 2;131 table[2].driver_data = 2;132 table[2].frequency = clock_tick / 32;133 table[3].driver_data = 0;134 table[3].frequency = CPUFREQ_TABLE_END;135 136 policy->cpuinfo.transition_latency = 0;137 policy->cur = clock_tick;138 policy->freq_table = table;139 140 return 0;141}142 143static void us3_freq_cpu_exit(struct cpufreq_policy *policy)144{145 us3_freq_target(policy, 0);146}147 148static struct cpufreq_driver cpufreq_us3_driver = {149 .name = "UltraSPARC-III",150 .init = us3_freq_cpu_init,151 .verify = cpufreq_generic_frequency_table_verify,152 .target_index = us3_freq_target,153 .get = us3_freq_get,154 .exit = us3_freq_cpu_exit,155};156 157static int __init us3_freq_init(void)158{159 unsigned long manuf, impl, ver;160 int ret;161 162 if (tlb_type != cheetah && tlb_type != cheetah_plus)163 return -ENODEV;164 165 __asm__("rdpr %%ver, %0" : "=r" (ver));166 manuf = ((ver >> 48) & 0xffff);167 impl = ((ver >> 32) & 0xffff);168 169 if (manuf == CHEETAH_MANUF &&170 (impl == CHEETAH_IMPL ||171 impl == CHEETAH_PLUS_IMPL ||172 impl == JAGUAR_IMPL ||173 impl == PANTHER_IMPL)) {174 us3_freq_table = kzalloc(NR_CPUS * sizeof(*us3_freq_table),175 GFP_KERNEL);176 if (!us3_freq_table)177 return -ENOMEM;178 179 ret = cpufreq_register_driver(&cpufreq_us3_driver);180 if (ret)181 kfree(us3_freq_table);182 183 return ret;184 }185 186 return -ENODEV;187}188 189static void __exit us3_freq_exit(void)190{191 cpufreq_unregister_driver(&cpufreq_us3_driver);192 kfree(us3_freq_table);193}194 195MODULE_AUTHOR("David S. Miller <davem@redhat.com>");196MODULE_DESCRIPTION("cpufreq driver for UltraSPARC-III");197MODULE_LICENSE("GPL");198 199module_init(us3_freq_init);200module_exit(us3_freq_exit);201