drivers/cpufreq/s3c24xx-cpufreq.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright (c) 2006-2008 Simtec Electronics
   4  *      http://armlinux.simtec.co.uk/
   5  *      Ben Dooks <ben@simtec.co.uk>
   6  *
   7  * S3C24XX CPU Frequency scaling
   8 */
   9
  10 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  11
  12 #include <linux/init.h>
  13 #include <linux/module.h>
  14 #include <linux/interrupt.h>
  15 #include <linux/ioport.h>
  16 #include <linux/cpufreq.h>
  17 #include <linux/cpu.h>
  18 #include <linux/clk.h>
  19 #include <linux/err.h>
  20 #include <linux/io.h>
  21 #include <linux/device.h>
  22 #include <linux/sysfs.h>
  23 #include <linux/slab.h>
  24 #include <linux/soc/samsung/s3c-cpufreq-core.h>
  25 #include <linux/soc/samsung/s3c-pm.h>
  26
  27 #include <asm/mach/arch.h>
  28 #include <asm/mach/map.h>
  29
  30 /* note, cpufreq support deals in kHz, no Hz */
  31 static struct cpufreq_driver s3c24xx_driver;
  32 static struct s3c_cpufreq_config cpu_cur;
  33 static struct s3c_iotimings s3c24xx_iotiming;
  34 static struct cpufreq_frequency_table *pll_reg;
  35 static unsigned int last_target = ~0;
  36 static unsigned int ftab_size;
  37 static struct cpufreq_frequency_table *ftab;
  38
  39 static struct clk *_clk_mpll;
  40 static struct clk *_clk_xtal;
  41 static struct clk *clk_fclk;
  42 static struct clk *clk_hclk;
  43 static struct clk *clk_pclk;
  44 static struct clk *clk_arm;
  45
  46 #ifdef CONFIG_ARM_S3C24XX_CPUFREQ_DEBUGFS
  47 struct s3c_cpufreq_config *s3c_cpufreq_getconfig(void)
  48 {
  49         return &cpu_cur;
  50 }
  51
  52 struct s3c_iotimings *s3c_cpufreq_getiotimings(void)
  53 {
  54         return &s3c24xx_iotiming;
  55 }
  56 #endif /* CONFIG_ARM_S3C24XX_CPUFREQ_DEBUGFS */
  57
  58 static void s3c_cpufreq_getcur(struct s3c_cpufreq_config *cfg)
  59 {
  60         unsigned long fclk, pclk, hclk, armclk;
  61
  62         cfg->freq.fclk = fclk = clk_get_rate(clk_fclk);
  63         cfg->freq.hclk = hclk = clk_get_rate(clk_hclk);
  64         cfg->freq.pclk = pclk = clk_get_rate(clk_pclk);
  65         cfg->freq.armclk = armclk = clk_get_rate(clk_arm);
  66
  67         cfg->pll.driver_data = s3c24xx_read_mpllcon();
  68         cfg->pll.frequency = fclk;
  69
  70         cfg->freq.hclk_tns = 1000000000 / (cfg->freq.hclk / 10);
  71
  72         cfg->divs.h_divisor = fclk / hclk;
  73         cfg->divs.p_divisor = fclk / pclk;
  74 }
  75
  76 static inline void s3c_cpufreq_calc(struct s3c_cpufreq_config *cfg)
  77 {
  78         unsigned long pll = cfg->pll.frequency;
  79
  80         cfg->freq.fclk = pll;
  81         cfg->freq.hclk = pll / cfg->divs.h_divisor;
  82         cfg->freq.pclk = pll / cfg->divs.p_divisor;
  83
  84         /* convert hclk into 10ths of nanoseconds for io calcs */
  85         cfg->freq.hclk_tns = 1000000000 / (cfg->freq.hclk / 10);
  86 }
  87
  88 static inline int closer(unsigned int target, unsigned int n, unsigned int c)
  89 {
  90         int diff_cur = abs(target - c);
  91         int diff_new = abs(target - n);
  92
  93         return (diff_new < diff_cur);
  94 }
  95
  96 static void s3c_cpufreq_show(const char *pfx,
  97                                  struct s3c_cpufreq_config *cfg)
  98 {
  99         s3c_freq_dbg("%s: Fvco=%u, F=%lu, A=%lu, H=%lu (%u), P=%lu (%u)\n",
 100                      pfx, cfg->pll.frequency, cfg->freq.fclk, cfg->freq.armclk,
 101                      cfg->freq.hclk, cfg->divs.h_divisor,
 102                      cfg->freq.pclk, cfg->divs.p_divisor);
 103 }
 104
 105 /* functions to wrapper the driver info calls to do the cpu specific work */
 106
 107 static void s3c_cpufreq_setio(struct s3c_cpufreq_config *cfg)
 108 {
 109         if (cfg->info->set_iotiming)
 110                 (cfg->info->set_iotiming)(cfg, &s3c24xx_iotiming);
 111 }
 112
 113 static int s3c_cpufreq_calcio(struct s3c_cpufreq_config *cfg)
 114 {
 115         if (cfg->info->calc_iotiming)
 116                 return (cfg->info->calc_iotiming)(cfg, &s3c24xx_iotiming);
 117
 118         return 0;
 119 }
 120
 121 static void s3c_cpufreq_setrefresh(struct s3c_cpufreq_config *cfg)
 122 {
 123         (cfg->info->set_refresh)(cfg);
 124 }
 125
 126 static void s3c_cpufreq_setdivs(struct s3c_cpufreq_config *cfg)
 127 {
 128         (cfg->info->set_divs)(cfg);
 129 }
 130
 131 static int s3c_cpufreq_calcdivs(struct s3c_cpufreq_config *cfg)
 132 {
 133         return (cfg->info->calc_divs)(cfg);
 134 }
 135
 136 static void s3c_cpufreq_setfvco(struct s3c_cpufreq_config *cfg)
 137 {
 138         cfg->mpll = _clk_mpll;
 139         (cfg->info->set_fvco)(cfg);
 140 }
 141
 142 static inline void s3c_cpufreq_updateclk(struct clk *clk,
 143                                          unsigned int freq)
 144 {
 145         clk_set_rate(clk, freq);
 146 }
 147
 148 static int s3c_cpufreq_settarget(struct cpufreq_policy *policy,
 149                                  unsigned int target_freq,
 150                                  struct cpufreq_frequency_table *pll)
 151 {
 152         struct s3c_cpufreq_freqs freqs;
 153         struct s3c_cpufreq_config cpu_new;
 154         unsigned long flags;
 155
 156         cpu_new = cpu_cur;  /* copy new from current */
 157
 158         s3c_cpufreq_show("cur", &cpu_cur);
 159
 160         /* TODO - check for DMA currently outstanding */
 161
 162         cpu_new.pll = pll ? *pll : cpu_cur.pll;
 163
 164         if (pll)
 165                 freqs.pll_changing = 1;
 166
 167         /* update our frequencies */
 168
 169         cpu_new.freq.armclk = target_freq;
 170         cpu_new.freq.fclk = cpu_new.pll.frequency;
 171
 172         if (s3c_cpufreq_calcdivs(&cpu_new) < 0) {
 173                 pr_err("no divisors for %d\n", target_freq);
 174                 goto err_notpossible;
 175         }
 176
 177         s3c_freq_dbg("%s: got divs\n", __func__);
 178
 179         s3c_cpufreq_calc(&cpu_new);
 180
 181         s3c_freq_dbg("%s: calculated frequencies for new\n", __func__);
 182
 183         if (cpu_new.freq.hclk != cpu_cur.freq.hclk) {
 184                 if (s3c_cpufreq_calcio(&cpu_new) < 0) {
 185                         pr_err("%s: no IO timings\n", __func__);
 186                         goto err_notpossible;
 187                 }
 188         }
 189
 190         s3c_cpufreq_show("new", &cpu_new);
 191
 192         /* setup our cpufreq parameters */
 193
 194         freqs.old = cpu_cur.freq;
 195         freqs.new = cpu_new.freq;
 196
 197         freqs.freqs.old = cpu_cur.freq.armclk / 1000;
 198         freqs.freqs.new = cpu_new.freq.armclk / 1000;
 199
 200         /* update f/h/p clock settings before we issue the change
 201          * notification, so that drivers do not need to do anything
 202          * special if they want to recalculate on CPUFREQ_PRECHANGE. */
 203
 204         s3c_cpufreq_updateclk(_clk_mpll, cpu_new.pll.frequency);
 205         s3c_cpufreq_updateclk(clk_fclk, cpu_new.freq.fclk);
 206         s3c_cpufreq_updateclk(clk_hclk, cpu_new.freq.hclk);
 207         s3c_cpufreq_updateclk(clk_pclk, cpu_new.freq.pclk);
 208
 209         /* start the frequency change */
 210         cpufreq_freq_transition_begin(policy, &freqs.freqs);
 211
 212         /* If hclk is staying the same, then we do not need to
 213          * re-write the IO or the refresh timings whilst we are changing
 214          * speed. */
 215
 216         local_irq_save(flags);
 217
 218         /* is our memory clock slowing down? */
 219         if (cpu_new.freq.hclk < cpu_cur.freq.hclk) {
 220                 s3c_cpufreq_setrefresh(&cpu_new);
 221                 s3c_cpufreq_setio(&cpu_new);
 222         }
 223
 224         if (cpu_new.freq.fclk == cpu_cur.freq.fclk) {
 225                 /* not changing PLL, just set the divisors */
 226
 227                 s3c_cpufreq_setdivs(&cpu_new);
 228         } else {
 229                 if (cpu_new.freq.fclk < cpu_cur.freq.fclk) {
 230                         /* slow the cpu down, then set divisors */
 231
 232                         s3c_cpufreq_setfvco(&cpu_new);
 233                         s3c_cpufreq_setdivs(&cpu_new);
 234                 } else {
 235                         /* set the divisors, then speed up */
 236
 237                         s3c_cpufreq_setdivs(&cpu_new);
 238                         s3c_cpufreq_setfvco(&cpu_new);
 239                 }
 240         }
 241
 242         /* did our memory clock speed up */
 243         if (cpu_new.freq.hclk > cpu_cur.freq.hclk) {
 244                 s3c_cpufreq_setrefresh(&cpu_new);
 245                 s3c_cpufreq_setio(&cpu_new);
 246         }
 247
 248         /* update our current settings */
 249         cpu_cur = cpu_new;
 250
 251         local_irq_restore(flags);
 252
 253         /* notify everyone we've done this */
 254         cpufreq_freq_transition_end(policy, &freqs.freqs, 0);
 255
 256         s3c_freq_dbg("%s: finished\n", __func__);
 257         return 0;
 258
 259  err_notpossible:
 260         pr_err("no compatible settings for %d\n", target_freq);
 261         return -EINVAL;
 262 }
 263
 264 /* s3c_cpufreq_target
 265  *
 266  * called by the cpufreq core to adjust the frequency that the CPU
 267  * is currently running at.
 268  */
 269
 270 static int s3c_cpufreq_target(struct cpufreq_policy *policy,
 271                               unsigned int target_freq,
 272                               unsigned int relation)
 273 {
 274         struct cpufreq_frequency_table *pll;
 275         unsigned int index;
 276
 277         /* avoid repeated calls which cause a needless amout of duplicated
 278          * logging output (and CPU time as the calculation process is
 279          * done) */
 280         if (target_freq == last_target)
 281                 return 0;
 282
 283         last_target = target_freq;
 284
 285         s3c_freq_dbg("%s: policy %p, target %u, relation %u\n",
 286                      __func__, policy, target_freq, relation);
 287
 288         if (ftab) {
 289                 index = cpufreq_frequency_table_target(policy, target_freq,
 290                                                        relation);
 291
 292                 s3c_freq_dbg("%s: adjust %d to entry %d (%u)\n", __func__,
 293                              target_freq, index, ftab[index].frequency);
 294                 target_freq = ftab[index].frequency;
 295         }
 296
 297         target_freq *= 1000;  /* convert target to Hz */
 298
 299         /* find the settings for our new frequency */
 300
 301         if (!pll_reg || cpu_cur.lock_pll) {
 302                 /* either we've not got any PLL values, or we've locked
 303                  * to the current one. */
 304                 pll = NULL;
 305         } else {
 306                 struct cpufreq_policy tmp_policy;
 307
 308                 /* we keep the cpu pll table in Hz, to ensure we get an
 309                  * accurate value for the PLL output. */
 310
 311                 tmp_policy.min = policy->min * 1000;
 312                 tmp_policy.max = policy->max * 1000;
 313                 tmp_policy.cpu = policy->cpu;
 314                 tmp_policy.freq_table = pll_reg;
 315
 316                 /* cpufreq_frequency_table_target returns the index
 317                  * of the table entry, not the value of
 318                  * the table entry's index field. */
 319
 320                 index = cpufreq_frequency_table_target(&tmp_policy, target_freq,
 321                                                        relation);
 322                 pll = pll_reg + index;
 323
 324                 s3c_freq_dbg("%s: target %u => %u\n",
 325                              __func__, target_freq, pll->frequency);
 326
 327                 target_freq = pll->frequency;
 328         }
 329
 330         return s3c_cpufreq_settarget(policy, target_freq, pll);
 331 }
 332
 333 struct clk *s3c_cpufreq_clk_get(struct device *dev, const char *name)
 334 {
 335         struct clk *clk;
 336
 337         clk = clk_get(dev, name);
 338         if (IS_ERR(clk))
 339                 pr_err("failed to get clock '%s'\n", name);
 340
 341         return clk;
 342 }
 343
 344 static int s3c_cpufreq_init(struct cpufreq_policy *policy)
 345 {
 346         policy->clk = clk_arm;
 347         policy->cpuinfo.transition_latency = cpu_cur.info->latency;
 348         policy->freq_table = ftab;
 349
 350         return 0;
 351 }
 352
 353 static int __init s3c_cpufreq_initclks(void)
 354 {
 355         _clk_mpll = s3c_cpufreq_clk_get(NULL, "mpll");
 356         _clk_xtal = s3c_cpufreq_clk_get(NULL, "xtal");
 357         clk_fclk = s3c_cpufreq_clk_get(NULL, "fclk");
 358         clk_hclk = s3c_cpufreq_clk_get(NULL, "hclk");
 359         clk_pclk = s3c_cpufreq_clk_get(NULL, "pclk");
 360         clk_arm = s3c_cpufreq_clk_get(NULL, "armclk");
 361
 362         if (IS_ERR(clk_fclk) || IS_ERR(clk_hclk) || IS_ERR(clk_pclk) ||
 363             IS_ERR(_clk_mpll) || IS_ERR(clk_arm) || IS_ERR(_clk_xtal)) {
 364                 pr_err("%s: could not get clock(s)\n", __func__);
 365                 return -ENOENT;
 366         }
 367
 368         pr_info("%s: clocks f=%lu,h=%lu,p=%lu,a=%lu\n",
 369                 __func__,
 370                 clk_get_rate(clk_fclk) / 1000,
 371                 clk_get_rate(clk_hclk) / 1000,
 372                 clk_get_rate(clk_pclk) / 1000,
 373                 clk_get_rate(clk_arm) / 1000);
 374
 375         return 0;
 376 }
 377
 378 #ifdef CONFIG_PM
 379 static struct cpufreq_frequency_table suspend_pll;
 380 static unsigned int suspend_freq;
 381
 382 static int s3c_cpufreq_suspend(struct cpufreq_policy *policy)
 383 {
 384         suspend_pll.frequency = clk_get_rate(_clk_mpll);
 385         suspend_pll.driver_data = s3c24xx_read_mpllcon();
 386         suspend_freq = clk_get_rate(clk_arm);
 387
 388         return 0;
 389 }
 390
 391 static int s3c_cpufreq_resume(struct cpufreq_policy *policy)
 392 {
 393         int ret;
 394
 395         s3c_freq_dbg("%s: resuming with policy %p\n", __func__, policy);
 396
 397         last_target = ~0;       /* invalidate last_target setting */
 398
 399         /* whilst we will be called later on, we try and re-set the
 400          * cpu frequencies as soon as possible so that we do not end
 401          * up resuming devices and then immediately having to re-set
 402          * a number of settings once these devices have restarted.
 403          *
 404          * as a note, it is expected devices are not used until they
 405          * have been un-suspended and at that time they should have
 406          * used the updated clock settings.
 407          */
 408
 409         ret = s3c_cpufreq_settarget(NULL, suspend_freq, &suspend_pll);
 410         if (ret) {
 411                 pr_err("%s: failed to reset pll/freq\n", __func__);
 412                 return ret;
 413         }
 414
 415         return 0;
 416 }
 417 #else
 418 #define s3c_cpufreq_resume NULL
 419 #define s3c_cpufreq_suspend NULL
 420 #endif
 421
 422 static struct cpufreq_driver s3c24xx_driver = {
 423         .flags          = CPUFREQ_NEED_INITIAL_FREQ_CHECK,
 424         .target         = s3c_cpufreq_target,
 425         .get            = cpufreq_generic_get,
 426         .init           = s3c_cpufreq_init,
 427         .suspend        = s3c_cpufreq_suspend,
 428         .resume         = s3c_cpufreq_resume,
 429         .name           = "s3c24xx",
 430 };
 431
 432
 433 int s3c_cpufreq_register(struct s3c_cpufreq_info *info)
 434 {
 435         if (!info || !info->name) {
 436                 pr_err("%s: failed to pass valid information\n", __func__);
 437                 return -EINVAL;
 438         }
 439
 440         pr_info("S3C24XX CPU Frequency driver, %s cpu support\n",
 441                 info->name);
 442
 443         /* check our driver info has valid data */
 444
 445         BUG_ON(info->set_refresh == NULL);
 446         BUG_ON(info->set_divs == NULL);
 447         BUG_ON(info->calc_divs == NULL);
 448
 449         /* info->set_fvco is optional, depending on whether there
 450          * is a need to set the clock code. */
 451
 452         cpu_cur.info = info;
 453
 454         /* Note, driver registering should probably update locktime */
 455
 456         return 0;
 457 }
 458
 459 int __init s3c_cpufreq_setboard(struct s3c_cpufreq_board *board)
 460 {
 461         struct s3c_cpufreq_board *ours;
 462
 463         if (!board) {
 464                 pr_info("%s: no board data\n", __func__);
 465                 return -EINVAL;
 466         }
 467
 468         /* Copy the board information so that each board can make this
 469          * initdata. */
 470
 471         ours = kzalloc(sizeof(*ours), GFP_KERNEL);
 472         if (!ours)
 473                 return -ENOMEM;
 474
 475         *ours = *board;
 476         cpu_cur.board = ours;
 477
 478         return 0;
 479 }
 480
 481 static int __init s3c_cpufreq_auto_io(void)
 482 {
 483         int ret;
 484
 485         if (!cpu_cur.info->get_iotiming) {
 486                 pr_err("%s: get_iotiming undefined\n", __func__);
 487                 return -ENOENT;
 488         }
 489
 490         pr_info("%s: working out IO settings\n", __func__);
 491
 492         ret = (cpu_cur.info->get_iotiming)(&cpu_cur, &s3c24xx_iotiming);
 493         if (ret)
 494                 pr_err("%s: failed to get timings\n", __func__);
 495
 496         return ret;
 497 }
 498
 499 /* if one or is zero, then return the other, otherwise return the min */
 500 #define do_min(_a, _b) ((_a) == 0 ? (_b) : (_b) == 0 ? (_a) : min(_a, _b))
 501
 502 /**
 503  * s3c_cpufreq_freq_min - find the minimum settings for the given freq.
 504  * @dst: The destination structure
 505  * @a: One argument.
 506  * @b: The other argument.
 507  *
 508  * Create a minimum of each frequency entry in the 'struct s3c_freq',
 509  * unless the entry is zero when it is ignored and the non-zero argument
 510  * used.
 511  */
 512 static void s3c_cpufreq_freq_min(struct s3c_freq *dst,
 513                                  struct s3c_freq *a, struct s3c_freq *b)
 514 {
 515         dst->fclk = do_min(a->fclk, b->fclk);
 516         dst->hclk = do_min(a->hclk, b->hclk);
 517         dst->pclk = do_min(a->pclk, b->pclk);
 518         dst->armclk = do_min(a->armclk, b->armclk);
 519 }
 520
 521 static inline u32 calc_locktime(u32 freq, u32 time_us)
 522 {
 523         u32 result;
 524
 525         result = freq * time_us;
 526         result = DIV_ROUND_UP(result, 1000 * 1000);
 527
 528         return result;
 529 }
 530
 531 static void s3c_cpufreq_update_loctkime(void)
 532 {
 533         unsigned int bits = cpu_cur.info->locktime_bits;
 534         u32 rate = (u32)clk_get_rate(_clk_xtal);
 535         u32 val;
 536
 537         if (bits == 0) {
 538                 WARN_ON(1);
 539                 return;
 540         }
 541
 542         val = calc_locktime(rate, cpu_cur.info->locktime_u) << bits;
 543         val |= calc_locktime(rate, cpu_cur.info->locktime_m);
 544
 545         pr_info("%s: new locktime is 0x%08x\n", __func__, val);
 546         s3c24xx_write_locktime(val);
 547 }
 548
 549 static int s3c_cpufreq_build_freq(void)
 550 {
 551         int size, ret;
 552
 553         kfree(ftab);
 554
 555         size = cpu_cur.info->calc_freqtable(&cpu_cur, NULL, 0);
 556         size++;
 557
 558         ftab = kcalloc(size, sizeof(*ftab), GFP_KERNEL);
 559         if (!ftab)
 560                 return -ENOMEM;
 561
 562         ftab_size = size;
 563
 564         ret = cpu_cur.info->calc_freqtable(&cpu_cur, ftab, size);
 565         s3c_cpufreq_addfreq(ftab, ret, size, CPUFREQ_TABLE_END);
 566
 567         return 0;
 568 }
 569
 570 static int __init s3c_cpufreq_initcall(void)
 571 {
 572         int ret = 0;
 573
 574         if (cpu_cur.info && cpu_cur.board) {
 575                 ret = s3c_cpufreq_initclks();
 576                 if (ret)
 577                         goto out;
 578
 579                 /* get current settings */
 580                 s3c_cpufreq_getcur(&cpu_cur);
 581                 s3c_cpufreq_show("cur", &cpu_cur);
 582
 583                 if (cpu_cur.board->auto_io) {
 584                         ret = s3c_cpufreq_auto_io();
 585                         if (ret) {
 586                                 pr_err("%s: failed to get io timing\n",
 587                                        __func__);
 588                                 goto out;
 589                         }
 590                 }
 591
 592                 if (cpu_cur.board->need_io && !cpu_cur.info->set_iotiming) {
 593                         pr_err("%s: no IO support registered\n", __func__);
 594                         ret = -EINVAL;
 595                         goto out;
 596                 }
 597
 598                 if (!cpu_cur.info->need_pll)
 599                         cpu_cur.lock_pll = 1;
 600
 601                 s3c_cpufreq_update_loctkime();
 602
 603                 s3c_cpufreq_freq_min(&cpu_cur.max, &cpu_cur.board->max,
 604                                      &cpu_cur.info->max);
 605
 606                 if (cpu_cur.info->calc_freqtable)
 607                         s3c_cpufreq_build_freq();
 608
 609                 ret = cpufreq_register_driver(&s3c24xx_driver);
 610         }
 611
 612  out:
 613         return ret;
 614 }
 615
 616 late_initcall(s3c_cpufreq_initcall);
 617
 618 /**
 619  * s3c_plltab_register - register CPU PLL table.
 620  * @plls: The list of PLL entries.
 621  * @plls_no: The size of the PLL entries @plls.
 622  *
 623  * Register the given set of PLLs with the system.
 624  */
 625 int s3c_plltab_register(struct cpufreq_frequency_table *plls,
 626                                unsigned int plls_no)
 627 {
 628         struct cpufreq_frequency_table *vals;
 629         unsigned int size;
 630
 631         size = sizeof(*vals) * (plls_no + 1);
 632
 633         vals = kzalloc(size, GFP_KERNEL);
 634         if (vals) {
 635                 memcpy(vals, plls, size);
 636                 pll_reg = vals;
 637
 638                 /* write a terminating entry, we don't store it in the
 639                  * table that is stored in the kernel */
 640                 vals += plls_no;
 641                 vals->frequency = CPUFREQ_TABLE_END;
 642
 643                 pr_info("%d PLL entries\n", plls_no);
 644         } else
 645                 pr_err("no memory for PLL tables\n");
 646
 647         return vals ? 0 : -ENOMEM;
 648 }