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 21 static struct cpufreq_driver *cpufreq_us3_driver; 22 23 struct us3_freq_percpu_info { 24 struct cpufreq_frequency_table table[4]; 25 }; 26 27 /* Indexed by cpu number. */ 28 static 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 38 static 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 48 static 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 57 static 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 79 static unsigned int us3_freq_get(unsigned int cpu) 80 { 81 cpumask_t cpus_allowed; 82 unsigned long reg; 83 unsigned int ret; 84 85 cpumask_copy(&cpus_allowed, tsk_cpus_allowed(current)); 86 set_cpus_allowed_ptr(current, cpumask_of(cpu)); 87 88 reg = read_safari_cfg(); 89 ret = get_current_freq(cpu, reg); 90 91 set_cpus_allowed_ptr(current, &cpus_allowed); 92 93 return ret; 94 } 95 96 static int us3_freq_target(struct cpufreq_policy *policy, unsigned int index) 97 { 98 unsigned int cpu = policy->cpu; 99 unsigned long new_bits, new_freq, reg; 100 cpumask_t cpus_allowed; 101 102 cpumask_copy(&cpus_allowed, tsk_cpus_allowed(current)); 103 set_cpus_allowed_ptr(current, cpumask_of(cpu)); 104 105 new_freq = sparc64_get_clock_tick(cpu) / 1000; 106 switch (index) { 107 case 0: 108 new_bits = SAFARI_CFG_DIV_1; 109 new_freq /= 1; 110 break; 111 case 1: 112 new_bits = SAFARI_CFG_DIV_2; 113 new_freq /= 2; 114 break; 115 case 2: 116 new_bits = SAFARI_CFG_DIV_32; 117 new_freq /= 32; 118 break; 119 120 default: 121 BUG(); 122 } 123 124 reg = read_safari_cfg(); 125 126 reg &= ~SAFARI_CFG_DIV_MASK; 127 reg |= new_bits; 128 write_safari_cfg(reg); 129 130 set_cpus_allowed_ptr(current, &cpus_allowed); 131 132 return 0; 133 } 134 135 static int __init us3_freq_cpu_init(struct cpufreq_policy *policy) 136 { 137 unsigned int cpu = policy->cpu; 138 unsigned long clock_tick = sparc64_get_clock_tick(cpu) / 1000; 139 struct cpufreq_frequency_table *table = 140 &us3_freq_table[cpu].table[0]; 141 142 table[0].driver_data = 0; 143 table[0].frequency = clock_tick / 1; 144 table[1].driver_data = 1; 145 table[1].frequency = clock_tick / 2; 146 table[2].driver_data = 2; 147 table[2].frequency = clock_tick / 32; 148 table[3].driver_data = 0; 149 table[3].frequency = CPUFREQ_TABLE_END; 150 151 policy->cpuinfo.transition_latency = 0; 152 policy->cur = clock_tick; 153 154 return cpufreq_table_validate_and_show(policy, table); 155 } 156 157 static int us3_freq_cpu_exit(struct cpufreq_policy *policy) 158 { 159 if (cpufreq_us3_driver) { 160 cpufreq_frequency_table_put_attr(policy->cpu); 161 us3_freq_target(policy, 0); 162 } 163 164 return 0; 165 } 166 167 static int __init us3_freq_init(void) 168 { 169 unsigned long manuf, impl, ver; 170 int ret; 171 172 if (tlb_type != cheetah && tlb_type != cheetah_plus) 173 return -ENODEV; 174 175 __asm__("rdpr %%ver, %0" : "=r" (ver)); 176 manuf = ((ver >> 48) & 0xffff); 177 impl = ((ver >> 32) & 0xffff); 178 179 if (manuf == CHEETAH_MANUF && 180 (impl == CHEETAH_IMPL || 181 impl == CHEETAH_PLUS_IMPL || 182 impl == JAGUAR_IMPL || 183 impl == PANTHER_IMPL)) { 184 struct cpufreq_driver *driver; 185 186 ret = -ENOMEM; 187 driver = kzalloc(sizeof(*driver), GFP_KERNEL); 188 if (!driver) 189 goto err_out; 190 191 us3_freq_table = kzalloc((NR_CPUS * sizeof(*us3_freq_table)), 192 GFP_KERNEL); 193 if (!us3_freq_table) 194 goto err_out; 195 196 driver->init = us3_freq_cpu_init; 197 driver->verify = cpufreq_generic_frequency_table_verify; 198 driver->target_index = us3_freq_target; 199 driver->get = us3_freq_get; 200 driver->exit = us3_freq_cpu_exit; 201 strcpy(driver->name, "UltraSPARC-III"); 202 203 cpufreq_us3_driver = driver; 204 ret = cpufreq_register_driver(driver); 205 if (ret) 206 goto err_out; 207 208 return 0; 209 210 err_out: 211 if (driver) { 212 kfree(driver); 213 cpufreq_us3_driver = NULL; 214 } 215 kfree(us3_freq_table); 216 us3_freq_table = NULL; 217 return ret; 218 } 219 220 return -ENODEV; 221 } 222 223 static void __exit us3_freq_exit(void) 224 { 225 if (cpufreq_us3_driver) { 226 cpufreq_unregister_driver(cpufreq_us3_driver); 227 kfree(cpufreq_us3_driver); 228 cpufreq_us3_driver = NULL; 229 kfree(us3_freq_table); 230 us3_freq_table = NULL; 231 } 232 } 233 234 MODULE_AUTHOR("David S. Miller <davem@redhat.com>"); 235 MODULE_DESCRIPTION("cpufreq driver for UltraSPARC-III"); 236 MODULE_LICENSE("GPL"); 237 238 module_init(us3_freq_init); 239 module_exit(us3_freq_exit); 240