Paul Burton | 3179d37 | 2014-04-14 11:00:56 +0100 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (C) 2014 Imagination Technologies |
| 3 | * Author: Paul Burton <paul.burton@imgtec.com> |
| 4 | * |
| 5 | * This program is free software; you can redistribute it and/or modify it |
| 6 | * under the terms of the GNU General Public License as published by the |
| 7 | * Free Software Foundation; either version 2 of the License, or (at your |
| 8 | * option) any later version. |
| 9 | */ |
| 10 | |
Paul Burton | ba75050 | 2016-09-14 11:00:27 +0100 | [diff] [blame] | 11 | #include <linux/cpuhotplug.h> |
Paul Burton | 3179d37 | 2014-04-14 11:00:56 +0100 | [diff] [blame] | 12 | #include <linux/init.h> |
| 13 | #include <linux/percpu.h> |
| 14 | #include <linux/slab.h> |
| 15 | |
| 16 | #include <asm/asm-offsets.h> |
| 17 | #include <asm/cacheflush.h> |
| 18 | #include <asm/cacheops.h> |
| 19 | #include <asm/idle.h> |
| 20 | #include <asm/mips-cm.h> |
| 21 | #include <asm/mips-cpc.h> |
| 22 | #include <asm/mipsmtregs.h> |
| 23 | #include <asm/pm.h> |
| 24 | #include <asm/pm-cps.h> |
| 25 | #include <asm/smp-cps.h> |
| 26 | #include <asm/uasm.h> |
| 27 | |
| 28 | /* |
| 29 | * cps_nc_entry_fn - type of a generated non-coherent state entry function |
| 30 | * @online: the count of online coupled VPEs |
| 31 | * @nc_ready_count: pointer to a non-coherent mapping of the core ready_count |
| 32 | * |
| 33 | * The code entering & exiting non-coherent states is generated at runtime |
| 34 | * using uasm, in order to ensure that the compiler cannot insert a stray |
| 35 | * memory access at an unfortunate time and to allow the generation of optimal |
| 36 | * core-specific code particularly for cache routines. If coupled_coherence |
| 37 | * is non-zero and this is the entry function for the CPS_PM_NC_WAIT state, |
| 38 | * returns the number of VPEs that were in the wait state at the point this |
| 39 | * VPE left it. Returns garbage if coupled_coherence is zero or this is not |
| 40 | * the entry function for CPS_PM_NC_WAIT. |
| 41 | */ |
| 42 | typedef unsigned (*cps_nc_entry_fn)(unsigned online, u32 *nc_ready_count); |
| 43 | |
| 44 | /* |
| 45 | * The entry point of the generated non-coherent idle state entry/exit |
| 46 | * functions. Actually per-core rather than per-CPU. |
| 47 | */ |
| 48 | static DEFINE_PER_CPU_READ_MOSTLY(cps_nc_entry_fn[CPS_PM_STATE_COUNT], |
| 49 | nc_asm_enter); |
| 50 | |
| 51 | /* Bitmap indicating which states are supported by the system */ |
| 52 | DECLARE_BITMAP(state_support, CPS_PM_STATE_COUNT); |
| 53 | |
| 54 | /* |
| 55 | * Indicates the number of coupled VPEs ready to operate in a non-coherent |
| 56 | * state. Actually per-core rather than per-CPU. |
| 57 | */ |
| 58 | static DEFINE_PER_CPU_ALIGNED(u32*, ready_count); |
| 59 | static DEFINE_PER_CPU_ALIGNED(void*, ready_count_alloc); |
| 60 | |
| 61 | /* Indicates online CPUs coupled with the current CPU */ |
| 62 | static DEFINE_PER_CPU_ALIGNED(cpumask_t, online_coupled); |
| 63 | |
| 64 | /* |
| 65 | * Used to synchronize entry to deep idle states. Actually per-core rather |
| 66 | * than per-CPU. |
| 67 | */ |
| 68 | static DEFINE_PER_CPU_ALIGNED(atomic_t, pm_barrier); |
| 69 | |
| 70 | /* Saved CPU state across the CPS_PM_POWER_GATED state */ |
| 71 | DEFINE_PER_CPU_ALIGNED(struct mips_static_suspend_state, cps_cpu_state); |
| 72 | |
| 73 | /* A somewhat arbitrary number of labels & relocs for uasm */ |
Paul Burton | ba75050 | 2016-09-14 11:00:27 +0100 | [diff] [blame] | 74 | static struct uasm_label labels[32]; |
| 75 | static struct uasm_reloc relocs[32]; |
Paul Burton | 3179d37 | 2014-04-14 11:00:56 +0100 | [diff] [blame] | 76 | |
Paul Burton | 3179d37 | 2014-04-14 11:00:56 +0100 | [diff] [blame] | 77 | enum mips_reg { |
| 78 | zero, at, v0, v1, a0, a1, a2, a3, |
| 79 | t0, t1, t2, t3, t4, t5, t6, t7, |
| 80 | s0, s1, s2, s3, s4, s5, s6, s7, |
| 81 | t8, t9, k0, k1, gp, sp, fp, ra, |
| 82 | }; |
| 83 | |
| 84 | bool cps_pm_support_state(enum cps_pm_state state) |
| 85 | { |
| 86 | return test_bit(state, state_support); |
| 87 | } |
| 88 | |
| 89 | static void coupled_barrier(atomic_t *a, unsigned online) |
| 90 | { |
| 91 | /* |
| 92 | * This function is effectively the same as |
| 93 | * cpuidle_coupled_parallel_barrier, which can't be used here since |
| 94 | * there's no cpuidle device. |
| 95 | */ |
| 96 | |
| 97 | if (!coupled_coherence) |
| 98 | return; |
| 99 | |
Paul Burton | 7c5491b | 2014-06-11 11:00:57 +0100 | [diff] [blame] | 100 | smp_mb__before_atomic(); |
Paul Burton | 3179d37 | 2014-04-14 11:00:56 +0100 | [diff] [blame] | 101 | atomic_inc(a); |
| 102 | |
| 103 | while (atomic_read(a) < online) |
| 104 | cpu_relax(); |
| 105 | |
| 106 | if (atomic_inc_return(a) == online * 2) { |
| 107 | atomic_set(a, 0); |
| 108 | return; |
| 109 | } |
| 110 | |
| 111 | while (atomic_read(a) > online) |
| 112 | cpu_relax(); |
| 113 | } |
| 114 | |
| 115 | int cps_pm_enter_state(enum cps_pm_state state) |
| 116 | { |
| 117 | unsigned cpu = smp_processor_id(); |
| 118 | unsigned core = current_cpu_data.core; |
| 119 | unsigned online, left; |
| 120 | cpumask_t *coupled_mask = this_cpu_ptr(&online_coupled); |
| 121 | u32 *core_ready_count, *nc_core_ready_count; |
| 122 | void *nc_addr; |
| 123 | cps_nc_entry_fn entry; |
| 124 | struct core_boot_config *core_cfg; |
| 125 | struct vpe_boot_config *vpe_cfg; |
| 126 | |
| 127 | /* Check that there is an entry function for this state */ |
| 128 | entry = per_cpu(nc_asm_enter, core)[state]; |
| 129 | if (!entry) |
| 130 | return -EINVAL; |
| 131 | |
| 132 | /* Calculate which coupled CPUs (VPEs) are online */ |
Matt Redfearn | 929d4f5 | 2016-09-07 10:45:17 +0100 | [diff] [blame] | 133 | #if defined(CONFIG_MIPS_MT) || defined(CONFIG_CPU_MIPSR6) |
Paul Burton | 3179d37 | 2014-04-14 11:00:56 +0100 | [diff] [blame] | 134 | if (cpu_online(cpu)) { |
| 135 | cpumask_and(coupled_mask, cpu_online_mask, |
| 136 | &cpu_sibling_map[cpu]); |
| 137 | online = cpumask_weight(coupled_mask); |
| 138 | cpumask_clear_cpu(cpu, coupled_mask); |
| 139 | } else |
| 140 | #endif |
| 141 | { |
| 142 | cpumask_clear(coupled_mask); |
| 143 | online = 1; |
| 144 | } |
| 145 | |
| 146 | /* Setup the VPE to run mips_cps_pm_restore when started again */ |
Masahiro Yamada | 97f2645 | 2016-08-03 13:45:50 -0700 | [diff] [blame] | 147 | if (IS_ENABLED(CONFIG_CPU_PM) && state == CPS_PM_POWER_GATED) { |
Paul Burton | 064231e | 2014-07-09 12:48:18 +0100 | [diff] [blame] | 148 | /* Power gating relies upon CPS SMP */ |
| 149 | if (!mips_cps_smp_in_use()) |
| 150 | return -EINVAL; |
| 151 | |
Paul Burton | 3179d37 | 2014-04-14 11:00:56 +0100 | [diff] [blame] | 152 | core_cfg = &mips_cps_core_bootcfg[core]; |
Paul Burton | c90e49f | 2014-07-09 12:48:21 +0100 | [diff] [blame] | 153 | vpe_cfg = &core_cfg->vpe_config[cpu_vpe_id(¤t_cpu_data)]; |
Paul Burton | 3179d37 | 2014-04-14 11:00:56 +0100 | [diff] [blame] | 154 | vpe_cfg->pc = (unsigned long)mips_cps_pm_restore; |
| 155 | vpe_cfg->gp = (unsigned long)current_thread_info(); |
| 156 | vpe_cfg->sp = 0; |
| 157 | } |
| 158 | |
| 159 | /* Indicate that this CPU might not be coherent */ |
| 160 | cpumask_clear_cpu(cpu, &cpu_coherent_mask); |
Paul Burton | 7c5491b | 2014-06-11 11:00:57 +0100 | [diff] [blame] | 161 | smp_mb__after_atomic(); |
Paul Burton | 3179d37 | 2014-04-14 11:00:56 +0100 | [diff] [blame] | 162 | |
| 163 | /* Create a non-coherent mapping of the core ready_count */ |
| 164 | core_ready_count = per_cpu(ready_count, core); |
| 165 | nc_addr = kmap_noncoherent(virt_to_page(core_ready_count), |
| 166 | (unsigned long)core_ready_count); |
| 167 | nc_addr += ((unsigned long)core_ready_count & ~PAGE_MASK); |
| 168 | nc_core_ready_count = nc_addr; |
| 169 | |
| 170 | /* Ensure ready_count is zero-initialised before the assembly runs */ |
| 171 | ACCESS_ONCE(*nc_core_ready_count) = 0; |
| 172 | coupled_barrier(&per_cpu(pm_barrier, core), online); |
| 173 | |
| 174 | /* Run the generated entry code */ |
| 175 | left = entry(online, nc_core_ready_count); |
| 176 | |
| 177 | /* Remove the non-coherent mapping of ready_count */ |
| 178 | kunmap_noncoherent(); |
| 179 | |
| 180 | /* Indicate that this CPU is definitely coherent */ |
| 181 | cpumask_set_cpu(cpu, &cpu_coherent_mask); |
| 182 | |
| 183 | /* |
| 184 | * If this VPE is the first to leave the non-coherent wait state then |
| 185 | * it needs to wake up any coupled VPEs still running their wait |
| 186 | * instruction so that they return to cpuidle, which can then complete |
| 187 | * coordination between the coupled VPEs & provide the governor with |
| 188 | * a chance to reflect on the length of time the VPEs were in the |
| 189 | * idle state. |
| 190 | */ |
| 191 | if (coupled_coherence && (state == CPS_PM_NC_WAIT) && (left == online)) |
| 192 | arch_send_call_function_ipi_mask(coupled_mask); |
| 193 | |
| 194 | return 0; |
| 195 | } |
| 196 | |
Paul Burton | ba75050 | 2016-09-14 11:00:27 +0100 | [diff] [blame] | 197 | static void cps_gen_cache_routine(u32 **pp, struct uasm_label **pl, |
| 198 | struct uasm_reloc **pr, |
| 199 | const struct cache_desc *cache, |
| 200 | unsigned op, int lbl) |
Paul Burton | 3179d37 | 2014-04-14 11:00:56 +0100 | [diff] [blame] | 201 | { |
| 202 | unsigned cache_size = cache->ways << cache->waybit; |
| 203 | unsigned i; |
| 204 | const unsigned unroll_lines = 32; |
| 205 | |
| 206 | /* If the cache isn't present this function has it easy */ |
| 207 | if (cache->flags & MIPS_CACHE_NOT_PRESENT) |
| 208 | return; |
| 209 | |
| 210 | /* Load base address */ |
| 211 | UASM_i_LA(pp, t0, (long)CKSEG0); |
| 212 | |
| 213 | /* Calculate end address */ |
| 214 | if (cache_size < 0x8000) |
| 215 | uasm_i_addiu(pp, t1, t0, cache_size); |
| 216 | else |
| 217 | UASM_i_LA(pp, t1, (long)(CKSEG0 + cache_size)); |
| 218 | |
| 219 | /* Start of cache op loop */ |
| 220 | uasm_build_label(pl, *pp, lbl); |
| 221 | |
| 222 | /* Generate the cache ops */ |
Markos Chandras | 0f2a148 | 2016-02-03 03:15:23 +0000 | [diff] [blame] | 223 | for (i = 0; i < unroll_lines; i++) { |
| 224 | if (cpu_has_mips_r6) { |
| 225 | uasm_i_cache(pp, op, 0, t0); |
| 226 | uasm_i_addiu(pp, t0, t0, cache->linesz); |
| 227 | } else { |
| 228 | uasm_i_cache(pp, op, i * cache->linesz, t0); |
| 229 | } |
| 230 | } |
Paul Burton | 3179d37 | 2014-04-14 11:00:56 +0100 | [diff] [blame] | 231 | |
Markos Chandras | 0f2a148 | 2016-02-03 03:15:23 +0000 | [diff] [blame] | 232 | if (!cpu_has_mips_r6) |
| 233 | /* Update the base address */ |
| 234 | uasm_i_addiu(pp, t0, t0, unroll_lines * cache->linesz); |
Paul Burton | 3179d37 | 2014-04-14 11:00:56 +0100 | [diff] [blame] | 235 | |
| 236 | /* Loop if we haven't reached the end address yet */ |
| 237 | uasm_il_bne(pp, pr, t0, t1, lbl); |
| 238 | uasm_i_nop(pp); |
| 239 | } |
| 240 | |
Paul Burton | ba75050 | 2016-09-14 11:00:27 +0100 | [diff] [blame] | 241 | static int cps_gen_flush_fsb(u32 **pp, struct uasm_label **pl, |
| 242 | struct uasm_reloc **pr, |
| 243 | const struct cpuinfo_mips *cpu_info, |
| 244 | int lbl) |
Paul Burton | 3179d37 | 2014-04-14 11:00:56 +0100 | [diff] [blame] | 245 | { |
| 246 | unsigned i, fsb_size = 8; |
| 247 | unsigned num_loads = (fsb_size * 3) / 2; |
| 248 | unsigned line_stride = 2; |
| 249 | unsigned line_size = cpu_info->dcache.linesz; |
| 250 | unsigned perf_counter, perf_event; |
| 251 | unsigned revision = cpu_info->processor_id & PRID_REV_MASK; |
| 252 | |
| 253 | /* |
| 254 | * Determine whether this CPU requires an FSB flush, and if so which |
| 255 | * performance counter/event reflect stalls due to a full FSB. |
| 256 | */ |
| 257 | switch (__get_cpu_type(cpu_info->cputype)) { |
| 258 | case CPU_INTERAPTIV: |
| 259 | perf_counter = 1; |
| 260 | perf_event = 51; |
| 261 | break; |
| 262 | |
| 263 | case CPU_PROAPTIV: |
| 264 | /* Newer proAptiv cores don't require this workaround */ |
| 265 | if (revision >= PRID_REV_ENCODE_332(1, 1, 0)) |
| 266 | return 0; |
| 267 | |
| 268 | /* On older ones it's unavailable */ |
| 269 | return -1; |
| 270 | |
Paul Burton | 3179d37 | 2014-04-14 11:00:56 +0100 | [diff] [blame] | 271 | default: |
Matt Redfearn | b97d0b9 | 2016-09-07 10:45:11 +0100 | [diff] [blame] | 272 | /* Assume that the CPU does not need this workaround */ |
| 273 | return 0; |
Paul Burton | 3179d37 | 2014-04-14 11:00:56 +0100 | [diff] [blame] | 274 | } |
| 275 | |
| 276 | /* |
| 277 | * Ensure that the fill/store buffer (FSB) is not holding the results |
| 278 | * of a prefetch, since if it is then the CPC sequencer may become |
| 279 | * stuck in the D3 (ClrBus) state whilst entering a low power state. |
| 280 | */ |
| 281 | |
| 282 | /* Preserve perf counter setup */ |
| 283 | uasm_i_mfc0(pp, t2, 25, (perf_counter * 2) + 0); /* PerfCtlN */ |
| 284 | uasm_i_mfc0(pp, t3, 25, (perf_counter * 2) + 1); /* PerfCntN */ |
| 285 | |
| 286 | /* Setup perf counter to count FSB full pipeline stalls */ |
| 287 | uasm_i_addiu(pp, t0, zero, (perf_event << 5) | 0xf); |
| 288 | uasm_i_mtc0(pp, t0, 25, (perf_counter * 2) + 0); /* PerfCtlN */ |
| 289 | uasm_i_ehb(pp); |
| 290 | uasm_i_mtc0(pp, zero, 25, (perf_counter * 2) + 1); /* PerfCntN */ |
| 291 | uasm_i_ehb(pp); |
| 292 | |
| 293 | /* Base address for loads */ |
| 294 | UASM_i_LA(pp, t0, (long)CKSEG0); |
| 295 | |
| 296 | /* Start of clear loop */ |
| 297 | uasm_build_label(pl, *pp, lbl); |
| 298 | |
| 299 | /* Perform some loads to fill the FSB */ |
| 300 | for (i = 0; i < num_loads; i++) |
| 301 | uasm_i_lw(pp, zero, i * line_size * line_stride, t0); |
| 302 | |
| 303 | /* |
| 304 | * Invalidate the new D-cache entries so that the cache will need |
| 305 | * refilling (via the FSB) if the loop is executed again. |
| 306 | */ |
| 307 | for (i = 0; i < num_loads; i++) { |
| 308 | uasm_i_cache(pp, Hit_Invalidate_D, |
| 309 | i * line_size * line_stride, t0); |
| 310 | uasm_i_cache(pp, Hit_Writeback_Inv_SD, |
| 311 | i * line_size * line_stride, t0); |
| 312 | } |
| 313 | |
Matt Redfearn | f6b43d9354 | 2016-09-07 10:45:12 +0100 | [diff] [blame] | 314 | /* Barrier ensuring previous cache invalidates are complete */ |
Matt Redfearn | 90b084b | 2016-09-07 10:45:15 +0100 | [diff] [blame] | 315 | uasm_i_sync(pp, STYPE_SYNC); |
Paul Burton | 3179d37 | 2014-04-14 11:00:56 +0100 | [diff] [blame] | 316 | uasm_i_ehb(pp); |
| 317 | |
| 318 | /* Check whether the pipeline stalled due to the FSB being full */ |
| 319 | uasm_i_mfc0(pp, t1, 25, (perf_counter * 2) + 1); /* PerfCntN */ |
| 320 | |
| 321 | /* Loop if it didn't */ |
| 322 | uasm_il_beqz(pp, pr, t1, lbl); |
| 323 | uasm_i_nop(pp); |
| 324 | |
| 325 | /* Restore perf counter 1. The count may well now be wrong... */ |
| 326 | uasm_i_mtc0(pp, t2, 25, (perf_counter * 2) + 0); /* PerfCtlN */ |
| 327 | uasm_i_ehb(pp); |
| 328 | uasm_i_mtc0(pp, t3, 25, (perf_counter * 2) + 1); /* PerfCntN */ |
| 329 | uasm_i_ehb(pp); |
| 330 | |
| 331 | return 0; |
| 332 | } |
| 333 | |
Paul Burton | ba75050 | 2016-09-14 11:00:27 +0100 | [diff] [blame] | 334 | static void cps_gen_set_top_bit(u32 **pp, struct uasm_label **pl, |
| 335 | struct uasm_reloc **pr, |
| 336 | unsigned r_addr, int lbl) |
Paul Burton | 3179d37 | 2014-04-14 11:00:56 +0100 | [diff] [blame] | 337 | { |
| 338 | uasm_i_lui(pp, t0, uasm_rel_hi(0x80000000)); |
| 339 | uasm_build_label(pl, *pp, lbl); |
| 340 | uasm_i_ll(pp, t1, 0, r_addr); |
| 341 | uasm_i_or(pp, t1, t1, t0); |
| 342 | uasm_i_sc(pp, t1, 0, r_addr); |
| 343 | uasm_il_beqz(pp, pr, t1, lbl); |
| 344 | uasm_i_nop(pp); |
| 345 | } |
| 346 | |
Paul Burton | ba75050 | 2016-09-14 11:00:27 +0100 | [diff] [blame] | 347 | static void *cps_gen_entry_code(unsigned cpu, enum cps_pm_state state) |
Paul Burton | 3179d37 | 2014-04-14 11:00:56 +0100 | [diff] [blame] | 348 | { |
| 349 | struct uasm_label *l = labels; |
| 350 | struct uasm_reloc *r = relocs; |
| 351 | u32 *buf, *p; |
| 352 | const unsigned r_online = a0; |
| 353 | const unsigned r_nc_count = a1; |
| 354 | const unsigned r_pcohctl = t7; |
| 355 | const unsigned max_instrs = 256; |
| 356 | unsigned cpc_cmd; |
| 357 | int err; |
| 358 | enum { |
| 359 | lbl_incready = 1, |
| 360 | lbl_poll_cont, |
| 361 | lbl_secondary_hang, |
| 362 | lbl_disable_coherence, |
| 363 | lbl_flush_fsb, |
| 364 | lbl_invicache, |
| 365 | lbl_flushdcache, |
| 366 | lbl_hang, |
| 367 | lbl_set_cont, |
| 368 | lbl_secondary_cont, |
| 369 | lbl_decready, |
| 370 | }; |
| 371 | |
| 372 | /* Allocate a buffer to hold the generated code */ |
| 373 | p = buf = kcalloc(max_instrs, sizeof(u32), GFP_KERNEL); |
| 374 | if (!buf) |
| 375 | return NULL; |
| 376 | |
| 377 | /* Clear labels & relocs ready for (re)use */ |
| 378 | memset(labels, 0, sizeof(labels)); |
| 379 | memset(relocs, 0, sizeof(relocs)); |
| 380 | |
Masahiro Yamada | 97f2645 | 2016-08-03 13:45:50 -0700 | [diff] [blame] | 381 | if (IS_ENABLED(CONFIG_CPU_PM) && state == CPS_PM_POWER_GATED) { |
Paul Burton | 064231e | 2014-07-09 12:48:18 +0100 | [diff] [blame] | 382 | /* Power gating relies upon CPS SMP */ |
| 383 | if (!mips_cps_smp_in_use()) |
| 384 | goto out_err; |
| 385 | |
Paul Burton | 3179d37 | 2014-04-14 11:00:56 +0100 | [diff] [blame] | 386 | /* |
| 387 | * Save CPU state. Note the non-standard calling convention |
| 388 | * with the return address placed in v0 to avoid clobbering |
| 389 | * the ra register before it is saved. |
| 390 | */ |
| 391 | UASM_i_LA(&p, t0, (long)mips_cps_pm_save); |
| 392 | uasm_i_jalr(&p, v0, t0); |
| 393 | uasm_i_nop(&p); |
| 394 | } |
| 395 | |
| 396 | /* |
| 397 | * Load addresses of required CM & CPC registers. This is done early |
| 398 | * because they're needed in both the enable & disable coherence steps |
| 399 | * but in the coupled case the enable step will only run on one VPE. |
| 400 | */ |
| 401 | UASM_i_LA(&p, r_pcohctl, (long)addr_gcr_cl_coherence()); |
| 402 | |
| 403 | if (coupled_coherence) { |
| 404 | /* Increment ready_count */ |
Matt Redfearn | 85e540b | 2016-09-07 10:45:14 +0100 | [diff] [blame] | 405 | uasm_i_sync(&p, STYPE_SYNC_MB); |
Paul Burton | 3179d37 | 2014-04-14 11:00:56 +0100 | [diff] [blame] | 406 | uasm_build_label(&l, p, lbl_incready); |
| 407 | uasm_i_ll(&p, t1, 0, r_nc_count); |
| 408 | uasm_i_addiu(&p, t2, t1, 1); |
| 409 | uasm_i_sc(&p, t2, 0, r_nc_count); |
| 410 | uasm_il_beqz(&p, &r, t2, lbl_incready); |
| 411 | uasm_i_addiu(&p, t1, t1, 1); |
| 412 | |
Matt Redfearn | f6b43d9354 | 2016-09-07 10:45:12 +0100 | [diff] [blame] | 413 | /* Barrier ensuring all CPUs see the updated r_nc_count value */ |
Matt Redfearn | 85e540b | 2016-09-07 10:45:14 +0100 | [diff] [blame] | 414 | uasm_i_sync(&p, STYPE_SYNC_MB); |
Paul Burton | 3179d37 | 2014-04-14 11:00:56 +0100 | [diff] [blame] | 415 | |
| 416 | /* |
| 417 | * If this is the last VPE to become ready for non-coherence |
| 418 | * then it should branch below. |
| 419 | */ |
| 420 | uasm_il_beq(&p, &r, t1, r_online, lbl_disable_coherence); |
| 421 | uasm_i_nop(&p); |
| 422 | |
| 423 | if (state < CPS_PM_POWER_GATED) { |
| 424 | /* |
| 425 | * Otherwise this is not the last VPE to become ready |
| 426 | * for non-coherence. It needs to wait until coherence |
| 427 | * has been disabled before proceeding, which it will do |
| 428 | * by polling for the top bit of ready_count being set. |
| 429 | */ |
| 430 | uasm_i_addiu(&p, t1, zero, -1); |
| 431 | uasm_build_label(&l, p, lbl_poll_cont); |
| 432 | uasm_i_lw(&p, t0, 0, r_nc_count); |
| 433 | uasm_il_bltz(&p, &r, t0, lbl_secondary_cont); |
| 434 | uasm_i_ehb(&p); |
Matt Redfearn | 929d4f5 | 2016-09-07 10:45:17 +0100 | [diff] [blame] | 435 | if (cpu_has_mipsmt) |
| 436 | uasm_i_yield(&p, zero, t1); |
Paul Burton | 3179d37 | 2014-04-14 11:00:56 +0100 | [diff] [blame] | 437 | uasm_il_b(&p, &r, lbl_poll_cont); |
| 438 | uasm_i_nop(&p); |
| 439 | } else { |
| 440 | /* |
| 441 | * The core will lose power & this VPE will not continue |
| 442 | * so it can simply halt here. |
| 443 | */ |
Matt Redfearn | 929d4f5 | 2016-09-07 10:45:17 +0100 | [diff] [blame] | 444 | if (cpu_has_mipsmt) { |
| 445 | /* Halt the VPE via C0 tchalt register */ |
| 446 | uasm_i_addiu(&p, t0, zero, TCHALT_H); |
| 447 | uasm_i_mtc0(&p, t0, 2, 4); |
| 448 | } else if (cpu_has_vp) { |
| 449 | /* Halt the VP via the CPC VP_STOP register */ |
| 450 | unsigned int vpe_id; |
| 451 | |
| 452 | vpe_id = cpu_vpe_id(&cpu_data[cpu]); |
| 453 | uasm_i_addiu(&p, t0, zero, 1 << vpe_id); |
| 454 | UASM_i_LA(&p, t1, (long)addr_cpc_cl_vp_stop()); |
| 455 | uasm_i_sw(&p, t0, 0, t1); |
| 456 | } else { |
| 457 | BUG(); |
| 458 | } |
Paul Burton | 3179d37 | 2014-04-14 11:00:56 +0100 | [diff] [blame] | 459 | uasm_build_label(&l, p, lbl_secondary_hang); |
| 460 | uasm_il_b(&p, &r, lbl_secondary_hang); |
| 461 | uasm_i_nop(&p); |
| 462 | } |
| 463 | } |
| 464 | |
| 465 | /* |
| 466 | * This is the point of no return - this VPE will now proceed to |
| 467 | * disable coherence. At this point we *must* be sure that no other |
| 468 | * VPE within the core will interfere with the L1 dcache. |
| 469 | */ |
| 470 | uasm_build_label(&l, p, lbl_disable_coherence); |
| 471 | |
| 472 | /* Invalidate the L1 icache */ |
| 473 | cps_gen_cache_routine(&p, &l, &r, &cpu_data[cpu].icache, |
| 474 | Index_Invalidate_I, lbl_invicache); |
| 475 | |
| 476 | /* Writeback & invalidate the L1 dcache */ |
| 477 | cps_gen_cache_routine(&p, &l, &r, &cpu_data[cpu].dcache, |
| 478 | Index_Writeback_Inv_D, lbl_flushdcache); |
| 479 | |
Matt Redfearn | f6b43d9354 | 2016-09-07 10:45:12 +0100 | [diff] [blame] | 480 | /* Barrier ensuring previous cache invalidates are complete */ |
Matt Redfearn | 90b084b | 2016-09-07 10:45:15 +0100 | [diff] [blame] | 481 | uasm_i_sync(&p, STYPE_SYNC); |
Paul Burton | 3179d37 | 2014-04-14 11:00:56 +0100 | [diff] [blame] | 482 | uasm_i_ehb(&p); |
| 483 | |
Matt Redfearn | 7745199 | 2016-09-07 10:45:18 +0100 | [diff] [blame] | 484 | if (mips_cm_revision() < CM_REV_CM3) { |
| 485 | /* |
| 486 | * Disable all but self interventions. The load from COHCTL is |
| 487 | * defined by the interAptiv & proAptiv SUMs as ensuring that the |
| 488 | * operation resulting from the preceding store is complete. |
| 489 | */ |
| 490 | uasm_i_addiu(&p, t0, zero, 1 << cpu_data[cpu].core); |
| 491 | uasm_i_sw(&p, t0, 0, r_pcohctl); |
| 492 | uasm_i_lw(&p, t0, 0, r_pcohctl); |
Paul Burton | 3179d37 | 2014-04-14 11:00:56 +0100 | [diff] [blame] | 493 | |
Matt Redfearn | 7745199 | 2016-09-07 10:45:18 +0100 | [diff] [blame] | 494 | /* Barrier to ensure write to coherence control is complete */ |
| 495 | uasm_i_sync(&p, STYPE_SYNC); |
| 496 | uasm_i_ehb(&p); |
| 497 | } |
Paul Burton | 3179d37 | 2014-04-14 11:00:56 +0100 | [diff] [blame] | 498 | |
| 499 | /* Disable coherence */ |
| 500 | uasm_i_sw(&p, zero, 0, r_pcohctl); |
| 501 | uasm_i_lw(&p, t0, 0, r_pcohctl); |
| 502 | |
| 503 | if (state >= CPS_PM_CLOCK_GATED) { |
| 504 | err = cps_gen_flush_fsb(&p, &l, &r, &cpu_data[cpu], |
| 505 | lbl_flush_fsb); |
| 506 | if (err) |
| 507 | goto out_err; |
| 508 | |
| 509 | /* Determine the CPC command to issue */ |
| 510 | switch (state) { |
| 511 | case CPS_PM_CLOCK_GATED: |
| 512 | cpc_cmd = CPC_Cx_CMD_CLOCKOFF; |
| 513 | break; |
| 514 | case CPS_PM_POWER_GATED: |
| 515 | cpc_cmd = CPC_Cx_CMD_PWRDOWN; |
| 516 | break; |
| 517 | default: |
| 518 | BUG(); |
| 519 | goto out_err; |
| 520 | } |
| 521 | |
| 522 | /* Issue the CPC command */ |
| 523 | UASM_i_LA(&p, t0, (long)addr_cpc_cl_cmd()); |
| 524 | uasm_i_addiu(&p, t1, zero, cpc_cmd); |
| 525 | uasm_i_sw(&p, t1, 0, t0); |
| 526 | |
| 527 | if (state == CPS_PM_POWER_GATED) { |
| 528 | /* If anything goes wrong just hang */ |
| 529 | uasm_build_label(&l, p, lbl_hang); |
| 530 | uasm_il_b(&p, &r, lbl_hang); |
| 531 | uasm_i_nop(&p); |
| 532 | |
| 533 | /* |
| 534 | * There's no point generating more code, the core is |
| 535 | * powered down & if powered back up will run from the |
| 536 | * reset vector not from here. |
| 537 | */ |
| 538 | goto gen_done; |
| 539 | } |
| 540 | |
Matt Redfearn | f6b43d9354 | 2016-09-07 10:45:12 +0100 | [diff] [blame] | 541 | /* Barrier to ensure write to CPC command is complete */ |
Matt Redfearn | 90b084b | 2016-09-07 10:45:15 +0100 | [diff] [blame] | 542 | uasm_i_sync(&p, STYPE_SYNC); |
Paul Burton | 3179d37 | 2014-04-14 11:00:56 +0100 | [diff] [blame] | 543 | uasm_i_ehb(&p); |
| 544 | } |
| 545 | |
| 546 | if (state == CPS_PM_NC_WAIT) { |
| 547 | /* |
| 548 | * At this point it is safe for all VPEs to proceed with |
| 549 | * execution. This VPE will set the top bit of ready_count |
| 550 | * to indicate to the other VPEs that they may continue. |
| 551 | */ |
| 552 | if (coupled_coherence) |
| 553 | cps_gen_set_top_bit(&p, &l, &r, r_nc_count, |
| 554 | lbl_set_cont); |
| 555 | |
| 556 | /* |
| 557 | * VPEs which did not disable coherence will continue |
| 558 | * executing, after coherence has been disabled, from this |
| 559 | * point. |
| 560 | */ |
| 561 | uasm_build_label(&l, p, lbl_secondary_cont); |
| 562 | |
| 563 | /* Now perform our wait */ |
| 564 | uasm_i_wait(&p, 0); |
| 565 | } |
| 566 | |
| 567 | /* |
| 568 | * Re-enable coherence. Note that for CPS_PM_NC_WAIT all coupled VPEs |
| 569 | * will run this. The first will actually re-enable coherence & the |
| 570 | * rest will just be performing a rather unusual nop. |
| 571 | */ |
Matt Redfearn | 7745199 | 2016-09-07 10:45:18 +0100 | [diff] [blame] | 572 | uasm_i_addiu(&p, t0, zero, mips_cm_revision() < CM_REV_CM3 |
| 573 | ? CM_GCR_Cx_COHERENCE_COHDOMAINEN_MSK |
| 574 | : CM3_GCR_Cx_COHERENCE_COHEN_MSK); |
| 575 | |
Paul Burton | 3179d37 | 2014-04-14 11:00:56 +0100 | [diff] [blame] | 576 | uasm_i_sw(&p, t0, 0, r_pcohctl); |
| 577 | uasm_i_lw(&p, t0, 0, r_pcohctl); |
| 578 | |
Matt Redfearn | f6b43d9354 | 2016-09-07 10:45:12 +0100 | [diff] [blame] | 579 | /* Barrier to ensure write to coherence control is complete */ |
Matt Redfearn | 90b084b | 2016-09-07 10:45:15 +0100 | [diff] [blame] | 580 | uasm_i_sync(&p, STYPE_SYNC); |
Paul Burton | 3179d37 | 2014-04-14 11:00:56 +0100 | [diff] [blame] | 581 | uasm_i_ehb(&p); |
| 582 | |
| 583 | if (coupled_coherence && (state == CPS_PM_NC_WAIT)) { |
| 584 | /* Decrement ready_count */ |
| 585 | uasm_build_label(&l, p, lbl_decready); |
Matt Redfearn | 85e540b | 2016-09-07 10:45:14 +0100 | [diff] [blame] | 586 | uasm_i_sync(&p, STYPE_SYNC_MB); |
Paul Burton | 3179d37 | 2014-04-14 11:00:56 +0100 | [diff] [blame] | 587 | uasm_i_ll(&p, t1, 0, r_nc_count); |
| 588 | uasm_i_addiu(&p, t2, t1, -1); |
| 589 | uasm_i_sc(&p, t2, 0, r_nc_count); |
| 590 | uasm_il_beqz(&p, &r, t2, lbl_decready); |
| 591 | uasm_i_andi(&p, v0, t1, (1 << fls(smp_num_siblings)) - 1); |
| 592 | |
Matt Redfearn | f6b43d9354 | 2016-09-07 10:45:12 +0100 | [diff] [blame] | 593 | /* Barrier ensuring all CPUs see the updated r_nc_count value */ |
Matt Redfearn | 85e540b | 2016-09-07 10:45:14 +0100 | [diff] [blame] | 594 | uasm_i_sync(&p, STYPE_SYNC_MB); |
Paul Burton | 3179d37 | 2014-04-14 11:00:56 +0100 | [diff] [blame] | 595 | } |
| 596 | |
| 597 | if (coupled_coherence && (state == CPS_PM_CLOCK_GATED)) { |
| 598 | /* |
| 599 | * At this point it is safe for all VPEs to proceed with |
| 600 | * execution. This VPE will set the top bit of ready_count |
| 601 | * to indicate to the other VPEs that they may continue. |
| 602 | */ |
| 603 | cps_gen_set_top_bit(&p, &l, &r, r_nc_count, lbl_set_cont); |
| 604 | |
| 605 | /* |
| 606 | * This core will be reliant upon another core sending a |
| 607 | * power-up command to the CPC in order to resume operation. |
| 608 | * Thus an arbitrary VPE can't trigger the core leaving the |
| 609 | * idle state and the one that disables coherence might as well |
| 610 | * be the one to re-enable it. The rest will continue from here |
| 611 | * after that has been done. |
| 612 | */ |
| 613 | uasm_build_label(&l, p, lbl_secondary_cont); |
| 614 | |
Matt Redfearn | f6b43d9354 | 2016-09-07 10:45:12 +0100 | [diff] [blame] | 615 | /* Barrier ensuring all CPUs see the updated r_nc_count value */ |
Matt Redfearn | 85e540b | 2016-09-07 10:45:14 +0100 | [diff] [blame] | 616 | uasm_i_sync(&p, STYPE_SYNC_MB); |
Paul Burton | 3179d37 | 2014-04-14 11:00:56 +0100 | [diff] [blame] | 617 | } |
| 618 | |
| 619 | /* The core is coherent, time to return to C code */ |
| 620 | uasm_i_jr(&p, ra); |
| 621 | uasm_i_nop(&p); |
| 622 | |
| 623 | gen_done: |
| 624 | /* Ensure the code didn't exceed the resources allocated for it */ |
| 625 | BUG_ON((p - buf) > max_instrs); |
| 626 | BUG_ON((l - labels) > ARRAY_SIZE(labels)); |
| 627 | BUG_ON((r - relocs) > ARRAY_SIZE(relocs)); |
| 628 | |
| 629 | /* Patch branch offsets */ |
| 630 | uasm_resolve_relocs(relocs, labels); |
| 631 | |
| 632 | /* Flush the icache */ |
| 633 | local_flush_icache_range((unsigned long)buf, (unsigned long)p); |
| 634 | |
| 635 | return buf; |
| 636 | out_err: |
| 637 | kfree(buf); |
| 638 | return NULL; |
| 639 | } |
| 640 | |
Paul Burton | ba75050 | 2016-09-14 11:00:27 +0100 | [diff] [blame] | 641 | static int cps_pm_online_cpu(unsigned int cpu) |
Paul Burton | 3179d37 | 2014-04-14 11:00:56 +0100 | [diff] [blame] | 642 | { |
| 643 | enum cps_pm_state state; |
| 644 | unsigned core = cpu_data[cpu].core; |
| 645 | unsigned dlinesz = cpu_data[cpu].dcache.linesz; |
| 646 | void *entry_fn, *core_rc; |
| 647 | |
| 648 | for (state = CPS_PM_NC_WAIT; state < CPS_PM_STATE_COUNT; state++) { |
| 649 | if (per_cpu(nc_asm_enter, core)[state]) |
| 650 | continue; |
| 651 | if (!test_bit(state, state_support)) |
| 652 | continue; |
| 653 | |
| 654 | entry_fn = cps_gen_entry_code(cpu, state); |
| 655 | if (!entry_fn) { |
| 656 | pr_err("Failed to generate core %u state %u entry\n", |
| 657 | core, state); |
| 658 | clear_bit(state, state_support); |
| 659 | } |
| 660 | |
| 661 | per_cpu(nc_asm_enter, core)[state] = entry_fn; |
| 662 | } |
| 663 | |
| 664 | if (!per_cpu(ready_count, core)) { |
| 665 | core_rc = kmalloc(dlinesz * 2, GFP_KERNEL); |
| 666 | if (!core_rc) { |
| 667 | pr_err("Failed allocate core %u ready_count\n", core); |
| 668 | return -ENOMEM; |
| 669 | } |
| 670 | per_cpu(ready_count_alloc, core) = core_rc; |
| 671 | |
| 672 | /* Ensure ready_count is aligned to a cacheline boundary */ |
| 673 | core_rc += dlinesz - 1; |
| 674 | core_rc = (void *)((unsigned long)core_rc & ~(dlinesz - 1)); |
| 675 | per_cpu(ready_count, core) = core_rc; |
| 676 | } |
| 677 | |
| 678 | return 0; |
| 679 | } |
| 680 | |
| 681 | static int __init cps_pm_init(void) |
| 682 | { |
Paul Burton | 3179d37 | 2014-04-14 11:00:56 +0100 | [diff] [blame] | 683 | /* A CM is required for all non-coherent states */ |
| 684 | if (!mips_cm_present()) { |
| 685 | pr_warn("pm-cps: no CM, non-coherent states unavailable\n"); |
Paul Burton | ba75050 | 2016-09-14 11:00:27 +0100 | [diff] [blame] | 686 | return 0; |
Paul Burton | 3179d37 | 2014-04-14 11:00:56 +0100 | [diff] [blame] | 687 | } |
| 688 | |
| 689 | /* |
| 690 | * If interrupts were enabled whilst running a wait instruction on a |
| 691 | * non-coherent core then the VPE may end up processing interrupts |
| 692 | * whilst non-coherent. That would be bad. |
| 693 | */ |
| 694 | if (cpu_wait == r4k_wait_irqoff) |
| 695 | set_bit(CPS_PM_NC_WAIT, state_support); |
| 696 | else |
| 697 | pr_warn("pm-cps: non-coherent wait unavailable\n"); |
| 698 | |
| 699 | /* Detect whether a CPC is present */ |
| 700 | if (mips_cpc_present()) { |
| 701 | /* Detect whether clock gating is implemented */ |
| 702 | if (read_cpc_cl_stat_conf() & CPC_Cx_STAT_CONF_CLKGAT_IMPL_MSK) |
| 703 | set_bit(CPS_PM_CLOCK_GATED, state_support); |
| 704 | else |
| 705 | pr_warn("pm-cps: CPC does not support clock gating\n"); |
| 706 | |
| 707 | /* Power gating is available with CPS SMP & any CPC */ |
| 708 | if (mips_cps_smp_in_use()) |
| 709 | set_bit(CPS_PM_POWER_GATED, state_support); |
| 710 | else |
| 711 | pr_warn("pm-cps: CPS SMP not in use, power gating unavailable\n"); |
| 712 | } else { |
| 713 | pr_warn("pm-cps: no CPC, clock & power gating unavailable\n"); |
| 714 | } |
| 715 | |
Paul Burton | ba75050 | 2016-09-14 11:00:27 +0100 | [diff] [blame] | 716 | return cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "AP_PM_CPS_CPU_ONLINE", |
| 717 | cps_pm_online_cpu, NULL); |
Paul Burton | 3179d37 | 2014-04-14 11:00:56 +0100 | [diff] [blame] | 718 | } |
| 719 | arch_initcall(cps_pm_init); |