1 /* 2 * PowerNV cpuidle code 3 * 4 * Copyright 2015 IBM Corp. 5 * 6 * This program is free software; you can redistribute it and/or 7 * modify it under the terms of the GNU General Public License 8 * as published by the Free Software Foundation; either version 9 * 2 of the License, or (at your option) any later version. 10 */ 11 12 #include <linux/types.h> 13 #include <linux/mm.h> 14 #include <linux/slab.h> 15 #include <linux/of.h> 16 #include <linux/device.h> 17 #include <linux/cpu.h> 18 19 #include <asm/firmware.h> 20 #include <asm/machdep.h> 21 #include <asm/opal.h> 22 #include <asm/cputhreads.h> 23 #include <asm/cpuidle.h> 24 #include <asm/code-patching.h> 25 #include <asm/smp.h> 26 27 #include "powernv.h" 28 #include "subcore.h" 29 30 /* Power ISA 3.0 allows for stop states 0x0 - 0xF */ 31 #define MAX_STOP_STATE 0xF 32 33 static u32 supported_cpuidle_states; 34 35 static int pnv_save_sprs_for_deep_states(void) 36 { 37 int cpu; 38 int rc; 39 40 /* 41 * hid0, hid1, hid4, hid5, hmeer and lpcr values are symmetric across 42 * all cpus at boot. Get these reg values of current cpu and use the 43 * same across all cpus. 44 */ 45 uint64_t lpcr_val = mfspr(SPRN_LPCR) & ~(u64)LPCR_PECE1; 46 uint64_t hid0_val = mfspr(SPRN_HID0); 47 uint64_t hid1_val = mfspr(SPRN_HID1); 48 uint64_t hid4_val = mfspr(SPRN_HID4); 49 uint64_t hid5_val = mfspr(SPRN_HID5); 50 uint64_t hmeer_val = mfspr(SPRN_HMEER); 51 52 for_each_possible_cpu(cpu) { 53 uint64_t pir = get_hard_smp_processor_id(cpu); 54 uint64_t hsprg0_val = (uint64_t)&paca[cpu]; 55 56 if (!cpu_has_feature(CPU_FTR_ARCH_300)) { 57 /* 58 * HSPRG0 is used to store the cpu's pointer to paca. 59 * Hence last 3 bits are guaranteed to be 0. Program 60 * slw to restore HSPRG0 with 63rd bit set, so that 61 * when a thread wakes up at 0x100 we can use this bit 62 * to distinguish between fastsleep and deep winkle. 63 * This is not necessary with stop/psscr since PLS 64 * field of psscr indicates which state we are waking 65 * up from. 66 */ 67 hsprg0_val |= 1; 68 } 69 rc = opal_slw_set_reg(pir, SPRN_HSPRG0, hsprg0_val); 70 if (rc != 0) 71 return rc; 72 73 rc = opal_slw_set_reg(pir, SPRN_LPCR, lpcr_val); 74 if (rc != 0) 75 return rc; 76 77 /* HIDs are per core registers */ 78 if (cpu_thread_in_core(cpu) == 0) { 79 80 rc = opal_slw_set_reg(pir, SPRN_HMEER, hmeer_val); 81 if (rc != 0) 82 return rc; 83 84 rc = opal_slw_set_reg(pir, SPRN_HID0, hid0_val); 85 if (rc != 0) 86 return rc; 87 88 rc = opal_slw_set_reg(pir, SPRN_HID1, hid1_val); 89 if (rc != 0) 90 return rc; 91 92 rc = opal_slw_set_reg(pir, SPRN_HID4, hid4_val); 93 if (rc != 0) 94 return rc; 95 96 rc = opal_slw_set_reg(pir, SPRN_HID5, hid5_val); 97 if (rc != 0) 98 return rc; 99 } 100 } 101 102 return 0; 103 } 104 105 static void pnv_alloc_idle_core_states(void) 106 { 107 int i, j; 108 int nr_cores = cpu_nr_cores(); 109 u32 *core_idle_state; 110 111 /* 112 * core_idle_state - First 8 bits track the idle state of each thread 113 * of the core. The 8th bit is the lock bit. Initially all thread bits 114 * are set. They are cleared when the thread enters deep idle state 115 * like sleep and winkle. Initially the lock bit is cleared. 116 * The lock bit has 2 purposes 117 * a. While the first thread is restoring core state, it prevents 118 * other threads in the core from switching to process context. 119 * b. While the last thread in the core is saving the core state, it 120 * prevents a different thread from waking up. 121 */ 122 for (i = 0; i < nr_cores; i++) { 123 int first_cpu = i * threads_per_core; 124 int node = cpu_to_node(first_cpu); 125 126 core_idle_state = kmalloc_node(sizeof(u32), GFP_KERNEL, node); 127 *core_idle_state = PNV_CORE_IDLE_THREAD_BITS; 128 129 for (j = 0; j < threads_per_core; j++) { 130 int cpu = first_cpu + j; 131 132 paca[cpu].core_idle_state_ptr = core_idle_state; 133 paca[cpu].thread_idle_state = PNV_THREAD_RUNNING; 134 paca[cpu].thread_mask = 1 << j; 135 } 136 } 137 138 update_subcore_sibling_mask(); 139 140 if (supported_cpuidle_states & OPAL_PM_LOSE_FULL_CONTEXT) 141 pnv_save_sprs_for_deep_states(); 142 } 143 144 u32 pnv_get_supported_cpuidle_states(void) 145 { 146 return supported_cpuidle_states; 147 } 148 EXPORT_SYMBOL_GPL(pnv_get_supported_cpuidle_states); 149 150 151 static void pnv_fastsleep_workaround_apply(void *info) 152 153 { 154 int rc; 155 int *err = info; 156 157 rc = opal_config_cpu_idle_state(OPAL_CONFIG_IDLE_FASTSLEEP, 158 OPAL_CONFIG_IDLE_APPLY); 159 if (rc) 160 *err = 1; 161 } 162 163 /* 164 * Used to store fastsleep workaround state 165 * 0 - Workaround applied/undone at fastsleep entry/exit path (Default) 166 * 1 - Workaround applied once, never undone. 167 */ 168 static u8 fastsleep_workaround_applyonce; 169 170 static ssize_t show_fastsleep_workaround_applyonce(struct device *dev, 171 struct device_attribute *attr, char *buf) 172 { 173 return sprintf(buf, "%u\n", fastsleep_workaround_applyonce); 174 } 175 176 static ssize_t store_fastsleep_workaround_applyonce(struct device *dev, 177 struct device_attribute *attr, const char *buf, 178 size_t count) 179 { 180 cpumask_t primary_thread_mask; 181 int err; 182 u8 val; 183 184 if (kstrtou8(buf, 0, &val) || val != 1) 185 return -EINVAL; 186 187 if (fastsleep_workaround_applyonce == 1) 188 return count; 189 190 /* 191 * fastsleep_workaround_applyonce = 1 implies 192 * fastsleep workaround needs to be left in 'applied' state on all 193 * the cores. Do this by- 194 * 1. Patching out the call to 'undo' workaround in fastsleep exit path 195 * 2. Sending ipi to all the cores which have at least one online thread 196 * 3. Patching out the call to 'apply' workaround in fastsleep entry 197 * path 198 * There is no need to send ipi to cores which have all threads 199 * offlined, as last thread of the core entering fastsleep or deeper 200 * state would have applied workaround. 201 */ 202 err = patch_instruction( 203 (unsigned int *)pnv_fastsleep_workaround_at_exit, 204 PPC_INST_NOP); 205 if (err) { 206 pr_err("fastsleep_workaround_applyonce change failed while patching pnv_fastsleep_workaround_at_exit"); 207 goto fail; 208 } 209 210 get_online_cpus(); 211 primary_thread_mask = cpu_online_cores_map(); 212 on_each_cpu_mask(&primary_thread_mask, 213 pnv_fastsleep_workaround_apply, 214 &err, 1); 215 put_online_cpus(); 216 if (err) { 217 pr_err("fastsleep_workaround_applyonce change failed while running pnv_fastsleep_workaround_apply"); 218 goto fail; 219 } 220 221 err = patch_instruction( 222 (unsigned int *)pnv_fastsleep_workaround_at_entry, 223 PPC_INST_NOP); 224 if (err) { 225 pr_err("fastsleep_workaround_applyonce change failed while patching pnv_fastsleep_workaround_at_entry"); 226 goto fail; 227 } 228 229 fastsleep_workaround_applyonce = 1; 230 231 return count; 232 fail: 233 return -EIO; 234 } 235 236 static DEVICE_ATTR(fastsleep_workaround_applyonce, 0600, 237 show_fastsleep_workaround_applyonce, 238 store_fastsleep_workaround_applyonce); 239 240 /* 241 * The default stop state that will be used by ppc_md.power_save 242 * function on platforms that support stop instruction. 243 */ 244 u64 pnv_default_stop_val; 245 u64 pnv_default_stop_mask; 246 247 /* 248 * Used for ppc_md.power_save which needs a function with no parameters 249 */ 250 static void power9_idle(void) 251 { 252 power9_idle_stop(pnv_default_stop_val, pnv_default_stop_mask); 253 } 254 255 /* 256 * First deep stop state. Used to figure out when to save/restore 257 * hypervisor context. 258 */ 259 u64 pnv_first_deep_stop_state = MAX_STOP_STATE; 260 261 /* 262 * psscr value and mask of the deepest stop idle state. 263 * Used when a cpu is offlined. 264 */ 265 u64 pnv_deepest_stop_psscr_val; 266 u64 pnv_deepest_stop_psscr_mask; 267 268 /* 269 * Power ISA 3.0 idle initialization. 270 * 271 * POWER ISA 3.0 defines a new SPR Processor stop Status and Control 272 * Register (PSSCR) to control idle behavior. 273 * 274 * PSSCR layout: 275 * ---------------------------------------------------------- 276 * | PLS | /// | SD | ESL | EC | PSLL | /// | TR | MTL | RL | 277 * ---------------------------------------------------------- 278 * 0 4 41 42 43 44 48 54 56 60 279 * 280 * PSSCR key fields: 281 * Bits 0:3 - Power-Saving Level Status (PLS). This field indicates the 282 * lowest power-saving state the thread entered since stop instruction was 283 * last executed. 284 * 285 * Bit 41 - Status Disable(SD) 286 * 0 - Shows PLS entries 287 * 1 - PLS entries are all 0 288 * 289 * Bit 42 - Enable State Loss 290 * 0 - No state is lost irrespective of other fields 291 * 1 - Allows state loss 292 * 293 * Bit 43 - Exit Criterion 294 * 0 - Exit from power-save mode on any interrupt 295 * 1 - Exit from power-save mode controlled by LPCR's PECE bits 296 * 297 * Bits 44:47 - Power-Saving Level Limit 298 * This limits the power-saving level that can be entered into. 299 * 300 * Bits 60:63 - Requested Level 301 * Used to specify which power-saving level must be entered on executing 302 * stop instruction 303 */ 304 305 int validate_psscr_val_mask(u64 *psscr_val, u64 *psscr_mask, u32 flags) 306 { 307 int err = 0; 308 309 /* 310 * psscr_mask == 0xf indicates an older firmware. 311 * Set remaining fields of psscr to the default values. 312 * See NOTE above definition of PSSCR_HV_DEFAULT_VAL 313 */ 314 if (*psscr_mask == 0xf) { 315 *psscr_val = *psscr_val | PSSCR_HV_DEFAULT_VAL; 316 *psscr_mask = PSSCR_HV_DEFAULT_MASK; 317 return err; 318 } 319 320 /* 321 * New firmware is expected to set the psscr_val bits correctly. 322 * Validate that the following invariants are correctly maintained by 323 * the new firmware. 324 * - ESL bit value matches the EC bit value. 325 * - ESL bit is set for all the deep stop states. 326 */ 327 if (GET_PSSCR_ESL(*psscr_val) != GET_PSSCR_EC(*psscr_val)) { 328 err = ERR_EC_ESL_MISMATCH; 329 } else if ((flags & OPAL_PM_LOSE_FULL_CONTEXT) && 330 GET_PSSCR_ESL(*psscr_val) == 0) { 331 err = ERR_DEEP_STATE_ESL_MISMATCH; 332 } 333 334 return err; 335 } 336 337 /* 338 * pnv_arch300_idle_init: Initializes the default idle state, first 339 * deep idle state and deepest idle state on 340 * ISA 3.0 CPUs. 341 * 342 * @np: /ibm,opal/power-mgt device node 343 * @flags: cpu-idle-state-flags array 344 * @dt_idle_states: Number of idle state entries 345 * Returns 0 on success 346 */ 347 static int __init pnv_power9_idle_init(struct device_node *np, u32 *flags, 348 int dt_idle_states) 349 { 350 u64 *psscr_val = NULL; 351 u64 *psscr_mask = NULL; 352 u32 *residency_ns = NULL; 353 u64 max_residency_ns = 0; 354 int rc = 0, i; 355 bool default_stop_found = false, deepest_stop_found = false; 356 357 psscr_val = kcalloc(dt_idle_states, sizeof(*psscr_val), GFP_KERNEL); 358 psscr_mask = kcalloc(dt_idle_states, sizeof(*psscr_mask), GFP_KERNEL); 359 residency_ns = kcalloc(dt_idle_states, sizeof(*residency_ns), 360 GFP_KERNEL); 361 362 if (!psscr_val || !psscr_mask || !residency_ns) { 363 rc = -1; 364 goto out; 365 } 366 367 if (of_property_read_u64_array(np, 368 "ibm,cpu-idle-state-psscr", 369 psscr_val, dt_idle_states)) { 370 pr_warn("cpuidle-powernv: missing ibm,cpu-idle-state-psscr in DT\n"); 371 rc = -1; 372 goto out; 373 } 374 375 if (of_property_read_u64_array(np, 376 "ibm,cpu-idle-state-psscr-mask", 377 psscr_mask, dt_idle_states)) { 378 pr_warn("cpuidle-powernv: missing ibm,cpu-idle-state-psscr-mask in DT\n"); 379 rc = -1; 380 goto out; 381 } 382 383 if (of_property_read_u32_array(np, 384 "ibm,cpu-idle-state-residency-ns", 385 residency_ns, dt_idle_states)) { 386 pr_warn("cpuidle-powernv: missing ibm,cpu-idle-state-residency-ns in DT\n"); 387 rc = -1; 388 goto out; 389 } 390 391 /* 392 * Set pnv_first_deep_stop_state, pnv_deepest_stop_psscr_{val,mask}, 393 * and the pnv_default_stop_{val,mask}. 394 * 395 * pnv_first_deep_stop_state should be set to the first stop 396 * level to cause hypervisor state loss. 397 * 398 * pnv_deepest_stop_{val,mask} should be set to values corresponding to 399 * the deepest stop state. 400 * 401 * pnv_default_stop_{val,mask} should be set to values corresponding to 402 * the shallowest (OPAL_PM_STOP_INST_FAST) loss-less stop state. 403 */ 404 pnv_first_deep_stop_state = MAX_STOP_STATE; 405 for (i = 0; i < dt_idle_states; i++) { 406 int err; 407 u64 psscr_rl = psscr_val[i] & PSSCR_RL_MASK; 408 409 if ((flags[i] & OPAL_PM_LOSE_FULL_CONTEXT) && 410 (pnv_first_deep_stop_state > psscr_rl)) 411 pnv_first_deep_stop_state = psscr_rl; 412 413 err = validate_psscr_val_mask(&psscr_val[i], &psscr_mask[i], 414 flags[i]); 415 if (err) { 416 report_invalid_psscr_val(psscr_val[i], err); 417 continue; 418 } 419 420 if (max_residency_ns < residency_ns[i]) { 421 max_residency_ns = residency_ns[i]; 422 pnv_deepest_stop_psscr_val = psscr_val[i]; 423 pnv_deepest_stop_psscr_mask = psscr_mask[i]; 424 deepest_stop_found = true; 425 } 426 427 if (!default_stop_found && 428 (flags[i] & OPAL_PM_STOP_INST_FAST)) { 429 pnv_default_stop_val = psscr_val[i]; 430 pnv_default_stop_mask = psscr_mask[i]; 431 default_stop_found = true; 432 } 433 } 434 435 if (!default_stop_found) { 436 pnv_default_stop_val = PSSCR_HV_DEFAULT_VAL; 437 pnv_default_stop_mask = PSSCR_HV_DEFAULT_MASK; 438 pr_warn("Setting default stop psscr val=0x%016llx,mask=0x%016llx\n", 439 pnv_default_stop_val, pnv_default_stop_mask); 440 } 441 442 if (!deepest_stop_found) { 443 pnv_deepest_stop_psscr_val = PSSCR_HV_DEFAULT_VAL; 444 pnv_deepest_stop_psscr_mask = PSSCR_HV_DEFAULT_MASK; 445 pr_warn("Setting default stop psscr val=0x%016llx,mask=0x%016llx\n", 446 pnv_deepest_stop_psscr_val, 447 pnv_deepest_stop_psscr_mask); 448 } 449 450 out: 451 kfree(psscr_val); 452 kfree(psscr_mask); 453 kfree(residency_ns); 454 return rc; 455 } 456 457 /* 458 * Probe device tree for supported idle states 459 */ 460 static void __init pnv_probe_idle_states(void) 461 { 462 struct device_node *np; 463 int dt_idle_states; 464 u32 *flags = NULL; 465 int i; 466 467 np = of_find_node_by_path("/ibm,opal/power-mgt"); 468 if (!np) { 469 pr_warn("opal: PowerMgmt Node not found\n"); 470 goto out; 471 } 472 dt_idle_states = of_property_count_u32_elems(np, 473 "ibm,cpu-idle-state-flags"); 474 if (dt_idle_states < 0) { 475 pr_warn("cpuidle-powernv: no idle states found in the DT\n"); 476 goto out; 477 } 478 479 flags = kcalloc(dt_idle_states, sizeof(*flags), GFP_KERNEL); 480 481 if (of_property_read_u32_array(np, 482 "ibm,cpu-idle-state-flags", flags, dt_idle_states)) { 483 pr_warn("cpuidle-powernv: missing ibm,cpu-idle-state-flags in DT\n"); 484 goto out; 485 } 486 487 if (cpu_has_feature(CPU_FTR_ARCH_300)) { 488 if (pnv_power9_idle_init(np, flags, dt_idle_states)) 489 goto out; 490 } 491 492 for (i = 0; i < dt_idle_states; i++) 493 supported_cpuidle_states |= flags[i]; 494 495 out: 496 kfree(flags); 497 } 498 static int __init pnv_init_idle_states(void) 499 { 500 501 supported_cpuidle_states = 0; 502 503 if (cpuidle_disable != IDLE_NO_OVERRIDE) 504 goto out; 505 506 pnv_probe_idle_states(); 507 508 if (!(supported_cpuidle_states & OPAL_PM_SLEEP_ENABLED_ER1)) { 509 patch_instruction( 510 (unsigned int *)pnv_fastsleep_workaround_at_entry, 511 PPC_INST_NOP); 512 patch_instruction( 513 (unsigned int *)pnv_fastsleep_workaround_at_exit, 514 PPC_INST_NOP); 515 } else { 516 /* 517 * OPAL_PM_SLEEP_ENABLED_ER1 is set. It indicates that 518 * workaround is needed to use fastsleep. Provide sysfs 519 * control to choose how this workaround has to be applied. 520 */ 521 device_create_file(cpu_subsys.dev_root, 522 &dev_attr_fastsleep_workaround_applyonce); 523 } 524 525 pnv_alloc_idle_core_states(); 526 527 if (supported_cpuidle_states & OPAL_PM_NAP_ENABLED) 528 ppc_md.power_save = power7_idle; 529 else if (supported_cpuidle_states & OPAL_PM_STOP_INST_FAST) 530 ppc_md.power_save = power9_idle; 531 532 out: 533 return 0; 534 } 535 machine_subsys_initcall(powernv, pnv_init_idle_states); 536