1 /* us2e_cpufreq.c: UltraSPARC-IIe 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/delay.h> 17 #include <linux/init.h> 18 19 #include <asm/asi.h> 20 #include <asm/timer.h> 21 22 static struct cpufreq_driver *cpufreq_us2e_driver; 23 24 struct us2e_freq_percpu_info { 25 struct cpufreq_frequency_table table[6]; 26 }; 27 28 /* Indexed by cpu number. */ 29 static struct us2e_freq_percpu_info *us2e_freq_table; 30 31 #define HBIRD_MEM_CNTL0_ADDR 0x1fe0000f010UL 32 #define HBIRD_ESTAR_MODE_ADDR 0x1fe0000f080UL 33 34 /* UltraSPARC-IIe has five dividers: 1, 2, 4, 6, and 8. These are controlled 35 * in the ESTAR mode control register. 36 */ 37 #define ESTAR_MODE_DIV_1 0x0000000000000000UL 38 #define ESTAR_MODE_DIV_2 0x0000000000000001UL 39 #define ESTAR_MODE_DIV_4 0x0000000000000003UL 40 #define ESTAR_MODE_DIV_6 0x0000000000000002UL 41 #define ESTAR_MODE_DIV_8 0x0000000000000004UL 42 #define ESTAR_MODE_DIV_MASK 0x0000000000000007UL 43 44 #define MCTRL0_SREFRESH_ENAB 0x0000000000010000UL 45 #define MCTRL0_REFR_COUNT_MASK 0x0000000000007f00UL 46 #define MCTRL0_REFR_COUNT_SHIFT 8 47 #define MCTRL0_REFR_INTERVAL 7800 48 #define MCTRL0_REFR_CLKS_P_CNT 64 49 50 static unsigned long read_hbreg(unsigned long addr) 51 { 52 unsigned long ret; 53 54 __asm__ __volatile__("ldxa [%1] %2, %0" 55 : "=&r" (ret) 56 : "r" (addr), "i" (ASI_PHYS_BYPASS_EC_E)); 57 return ret; 58 } 59 60 static void write_hbreg(unsigned long addr, unsigned long val) 61 { 62 __asm__ __volatile__("stxa %0, [%1] %2\n\t" 63 "membar #Sync" 64 : /* no outputs */ 65 : "r" (val), "r" (addr), "i" (ASI_PHYS_BYPASS_EC_E) 66 : "memory"); 67 if (addr == HBIRD_ESTAR_MODE_ADDR) { 68 /* Need to wait 16 clock cycles for the PLL to lock. */ 69 udelay(1); 70 } 71 } 72 73 static void self_refresh_ctl(int enable) 74 { 75 unsigned long mctrl = read_hbreg(HBIRD_MEM_CNTL0_ADDR); 76 77 if (enable) 78 mctrl |= MCTRL0_SREFRESH_ENAB; 79 else 80 mctrl &= ~MCTRL0_SREFRESH_ENAB; 81 write_hbreg(HBIRD_MEM_CNTL0_ADDR, mctrl); 82 (void) read_hbreg(HBIRD_MEM_CNTL0_ADDR); 83 } 84 85 static void frob_mem_refresh(int cpu_slowing_down, 86 unsigned long clock_tick, 87 unsigned long old_divisor, unsigned long divisor) 88 { 89 unsigned long old_refr_count, refr_count, mctrl; 90 91 refr_count = (clock_tick * MCTRL0_REFR_INTERVAL); 92 refr_count /= (MCTRL0_REFR_CLKS_P_CNT * divisor * 1000000000UL); 93 94 mctrl = read_hbreg(HBIRD_MEM_CNTL0_ADDR); 95 old_refr_count = (mctrl & MCTRL0_REFR_COUNT_MASK) 96 >> MCTRL0_REFR_COUNT_SHIFT; 97 98 mctrl &= ~MCTRL0_REFR_COUNT_MASK; 99 mctrl |= refr_count << MCTRL0_REFR_COUNT_SHIFT; 100 write_hbreg(HBIRD_MEM_CNTL0_ADDR, mctrl); 101 mctrl = read_hbreg(HBIRD_MEM_CNTL0_ADDR); 102 103 if (cpu_slowing_down && !(mctrl & MCTRL0_SREFRESH_ENAB)) { 104 unsigned long usecs; 105 106 /* We have to wait for both refresh counts (old 107 * and new) to go to zero. 108 */ 109 usecs = (MCTRL0_REFR_CLKS_P_CNT * 110 (refr_count + old_refr_count) * 111 1000000UL * 112 old_divisor) / clock_tick; 113 udelay(usecs + 1UL); 114 } 115 } 116 117 static void us2e_transition(unsigned long estar, unsigned long new_bits, 118 unsigned long clock_tick, 119 unsigned long old_divisor, unsigned long divisor) 120 { 121 unsigned long flags; 122 123 local_irq_save(flags); 124 125 estar &= ~ESTAR_MODE_DIV_MASK; 126 127 /* This is based upon the state transition diagram in the IIe manual. */ 128 if (old_divisor == 2 && divisor == 1) { 129 self_refresh_ctl(0); 130 write_hbreg(HBIRD_ESTAR_MODE_ADDR, estar | new_bits); 131 frob_mem_refresh(0, clock_tick, old_divisor, divisor); 132 } else if (old_divisor == 1 && divisor == 2) { 133 frob_mem_refresh(1, clock_tick, old_divisor, divisor); 134 write_hbreg(HBIRD_ESTAR_MODE_ADDR, estar | new_bits); 135 self_refresh_ctl(1); 136 } else if (old_divisor == 1 && divisor > 2) { 137 us2e_transition(estar, ESTAR_MODE_DIV_2, clock_tick, 138 1, 2); 139 us2e_transition(estar, new_bits, clock_tick, 140 2, divisor); 141 } else if (old_divisor > 2 && divisor == 1) { 142 us2e_transition(estar, ESTAR_MODE_DIV_2, clock_tick, 143 old_divisor, 2); 144 us2e_transition(estar, new_bits, clock_tick, 145 2, divisor); 146 } else if (old_divisor < divisor) { 147 frob_mem_refresh(0, clock_tick, old_divisor, divisor); 148 write_hbreg(HBIRD_ESTAR_MODE_ADDR, estar | new_bits); 149 } else if (old_divisor > divisor) { 150 write_hbreg(HBIRD_ESTAR_MODE_ADDR, estar | new_bits); 151 frob_mem_refresh(1, clock_tick, old_divisor, divisor); 152 } else { 153 BUG(); 154 } 155 156 local_irq_restore(flags); 157 } 158 159 static unsigned long index_to_estar_mode(unsigned int index) 160 { 161 switch (index) { 162 case 0: 163 return ESTAR_MODE_DIV_1; 164 165 case 1: 166 return ESTAR_MODE_DIV_2; 167 168 case 2: 169 return ESTAR_MODE_DIV_4; 170 171 case 3: 172 return ESTAR_MODE_DIV_6; 173 174 case 4: 175 return ESTAR_MODE_DIV_8; 176 177 default: 178 BUG(); 179 } 180 } 181 182 static unsigned long index_to_divisor(unsigned int index) 183 { 184 switch (index) { 185 case 0: 186 return 1; 187 188 case 1: 189 return 2; 190 191 case 2: 192 return 4; 193 194 case 3: 195 return 6; 196 197 case 4: 198 return 8; 199 200 default: 201 BUG(); 202 } 203 } 204 205 static unsigned long estar_to_divisor(unsigned long estar) 206 { 207 unsigned long ret; 208 209 switch (estar & ESTAR_MODE_DIV_MASK) { 210 case ESTAR_MODE_DIV_1: 211 ret = 1; 212 break; 213 case ESTAR_MODE_DIV_2: 214 ret = 2; 215 break; 216 case ESTAR_MODE_DIV_4: 217 ret = 4; 218 break; 219 case ESTAR_MODE_DIV_6: 220 ret = 6; 221 break; 222 case ESTAR_MODE_DIV_8: 223 ret = 8; 224 break; 225 default: 226 BUG(); 227 } 228 229 return ret; 230 } 231 232 static unsigned int us2e_freq_get(unsigned int cpu) 233 { 234 cpumask_t cpus_allowed; 235 unsigned long clock_tick, estar; 236 237 cpumask_copy(&cpus_allowed, ¤t->cpus_allowed); 238 set_cpus_allowed_ptr(current, cpumask_of(cpu)); 239 240 clock_tick = sparc64_get_clock_tick(cpu) / 1000; 241 estar = read_hbreg(HBIRD_ESTAR_MODE_ADDR); 242 243 set_cpus_allowed_ptr(current, &cpus_allowed); 244 245 return clock_tick / estar_to_divisor(estar); 246 } 247 248 static int us2e_freq_target(struct cpufreq_policy *policy, unsigned int index) 249 { 250 unsigned int cpu = policy->cpu; 251 unsigned long new_bits, new_freq; 252 unsigned long clock_tick, divisor, old_divisor, estar; 253 cpumask_t cpus_allowed; 254 255 cpumask_copy(&cpus_allowed, ¤t->cpus_allowed); 256 set_cpus_allowed_ptr(current, cpumask_of(cpu)); 257 258 new_freq = clock_tick = sparc64_get_clock_tick(cpu) / 1000; 259 new_bits = index_to_estar_mode(index); 260 divisor = index_to_divisor(index); 261 new_freq /= divisor; 262 263 estar = read_hbreg(HBIRD_ESTAR_MODE_ADDR); 264 265 old_divisor = estar_to_divisor(estar); 266 267 if (old_divisor != divisor) 268 us2e_transition(estar, new_bits, clock_tick * 1000, 269 old_divisor, divisor); 270 271 set_cpus_allowed_ptr(current, &cpus_allowed); 272 273 return 0; 274 } 275 276 static int __init us2e_freq_cpu_init(struct cpufreq_policy *policy) 277 { 278 unsigned int cpu = policy->cpu; 279 unsigned long clock_tick = sparc64_get_clock_tick(cpu) / 1000; 280 struct cpufreq_frequency_table *table = 281 &us2e_freq_table[cpu].table[0]; 282 283 table[0].driver_data = 0; 284 table[0].frequency = clock_tick / 1; 285 table[1].driver_data = 1; 286 table[1].frequency = clock_tick / 2; 287 table[2].driver_data = 2; 288 table[2].frequency = clock_tick / 4; 289 table[2].driver_data = 3; 290 table[2].frequency = clock_tick / 6; 291 table[2].driver_data = 4; 292 table[2].frequency = clock_tick / 8; 293 table[2].driver_data = 5; 294 table[3].frequency = CPUFREQ_TABLE_END; 295 296 policy->cpuinfo.transition_latency = 0; 297 policy->cur = clock_tick; 298 299 return cpufreq_table_validate_and_show(policy, table); 300 } 301 302 static int us2e_freq_cpu_exit(struct cpufreq_policy *policy) 303 { 304 if (cpufreq_us2e_driver) 305 us2e_freq_target(policy, 0); 306 307 return 0; 308 } 309 310 static int __init us2e_freq_init(void) 311 { 312 unsigned long manuf, impl, ver; 313 int ret; 314 315 if (tlb_type != spitfire) 316 return -ENODEV; 317 318 __asm__("rdpr %%ver, %0" : "=r" (ver)); 319 manuf = ((ver >> 48) & 0xffff); 320 impl = ((ver >> 32) & 0xffff); 321 322 if (manuf == 0x17 && impl == 0x13) { 323 struct cpufreq_driver *driver; 324 325 ret = -ENOMEM; 326 driver = kzalloc(sizeof(*driver), GFP_KERNEL); 327 if (!driver) 328 goto err_out; 329 330 us2e_freq_table = kzalloc((NR_CPUS * sizeof(*us2e_freq_table)), 331 GFP_KERNEL); 332 if (!us2e_freq_table) 333 goto err_out; 334 335 driver->init = us2e_freq_cpu_init; 336 driver->verify = cpufreq_generic_frequency_table_verify; 337 driver->target_index = us2e_freq_target; 338 driver->get = us2e_freq_get; 339 driver->exit = us2e_freq_cpu_exit; 340 strcpy(driver->name, "UltraSPARC-IIe"); 341 342 cpufreq_us2e_driver = driver; 343 ret = cpufreq_register_driver(driver); 344 if (ret) 345 goto err_out; 346 347 return 0; 348 349 err_out: 350 if (driver) { 351 kfree(driver); 352 cpufreq_us2e_driver = NULL; 353 } 354 kfree(us2e_freq_table); 355 us2e_freq_table = NULL; 356 return ret; 357 } 358 359 return -ENODEV; 360 } 361 362 static void __exit us2e_freq_exit(void) 363 { 364 if (cpufreq_us2e_driver) { 365 cpufreq_unregister_driver(cpufreq_us2e_driver); 366 kfree(cpufreq_us2e_driver); 367 cpufreq_us2e_driver = NULL; 368 kfree(us2e_freq_table); 369 us2e_freq_table = NULL; 370 } 371 } 372 373 MODULE_AUTHOR("David S. Miller <davem@redhat.com>"); 374 MODULE_DESCRIPTION("cpufreq driver for UltraSPARC-IIe"); 375 MODULE_LICENSE("GPL"); 376 377 module_init(us2e_freq_init); 378 module_exit(us2e_freq_exit); 379