drivers/clocksource/sh_cmt.c

   1 /*
   2  * SuperH Timer Support - CMT
   3  *
   4  *  Copyright (C) 2008 Magnus Damm
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 2 of the License
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  */
  15
  16 #include <linux/clk.h>
  17 #include <linux/clockchips.h>
  18 #include <linux/clocksource.h>
  19 #include <linux/delay.h>
  20 #include <linux/err.h>
  21 #include <linux/init.h>
  22 #include <linux/interrupt.h>
  23 #include <linux/io.h>
  24 #include <linux/ioport.h>
  25 #include <linux/irq.h>
  26 #include <linux/module.h>
  27 #include <linux/of.h>
  28 #include <linux/platform_device.h>
  29 #include <linux/pm_domain.h>
  30 #include <linux/pm_runtime.h>
  31 #include <linux/sh_timer.h>
  32 #include <linux/slab.h>
  33 #include <linux/spinlock.h>
  34
  35 struct sh_cmt_device;
  36
  37 /*
  38  * The CMT comes in 5 different identified flavours, depending not only on the
  39  * SoC but also on the particular instance. The following table lists the main
  40  * characteristics of those flavours.
  41  *
  42  *                      16B     32B     32B-F   48B     48B-2
  43  * -----------------------------------------------------------------------------
  44  * Channels             2       1/4     1       6       2/8
  45  * Control Width        16      16      16      16      32
  46  * Counter Width        16      32      32      32/48   32/48
  47  * Shared Start/Stop    Y       Y       Y       Y       N
  48  *
  49  * The 48-bit gen2 version has a per-channel start/stop register located in the
  50  * channel registers block. All other versions have a shared start/stop register
  51  * located in the global space.
  52  *
  53  * Channels are indexed from 0 to N-1 in the documentation. The channel index
  54  * infers the start/stop bit position in the control register and the channel
  55  * registers block address. Some CMT instances have a subset of channels
  56  * available, in which case the index in the documentation doesn't match the
  57  * "real" index as implemented in hardware. This is for instance the case with
  58  * CMT0 on r8a7740, which is a 32-bit variant with a single channel numbered 0
  59  * in the documentation but using start/stop bit 5 and having its registers
  60  * block at 0x60.
  61  *
  62  * Similarly CMT0 on r8a73a4, r8a7790 and r8a7791, while implementing 32-bit
  63  * channels only, is a 48-bit gen2 CMT with the 48-bit channels unavailable.
  64  */
  65
  66 enum sh_cmt_model {
  67         SH_CMT_16BIT,
  68         SH_CMT_32BIT,
  69         SH_CMT_32BIT_FAST,
  70         SH_CMT_48BIT,
  71         SH_CMT_48BIT_GEN2,
  72 };
  73
  74 struct sh_cmt_info {
  75         enum sh_cmt_model model;
  76
  77         unsigned long width; /* 16 or 32 bit version of hardware block */
  78         unsigned long overflow_bit;
  79         unsigned long clear_bits;
  80
  81         /* callbacks for CMSTR and CMCSR access */
  82         unsigned long (*read_control)(void __iomem *base, unsigned long offs);
  83         void (*write_control)(void __iomem *base, unsigned long offs,
  84                               unsigned long value);
  85
  86         /* callbacks for CMCNT and CMCOR access */
  87         unsigned long (*read_count)(void __iomem *base, unsigned long offs);
  88         void (*write_count)(void __iomem *base, unsigned long offs,
  89                             unsigned long value);
  90 };
  91
  92 struct sh_cmt_channel {
  93         struct sh_cmt_device *cmt;
  94
  95         unsigned int index;     /* Index in the documentation */
  96         unsigned int hwidx;     /* Real hardware index */
  97
  98         void __iomem *iostart;
  99         void __iomem *ioctrl;
 100
 101         unsigned int timer_bit;
 102         unsigned long flags;
 103         unsigned long match_value;
 104         unsigned long next_match_value;
 105         unsigned long max_match_value;
 106         raw_spinlock_t lock;
 107         struct clock_event_device ced;
 108         struct clocksource cs;
 109         unsigned long total_cycles;
 110         bool cs_enabled;
 111 };
 112
 113 struct sh_cmt_device {
 114         struct platform_device *pdev;
 115
 116         const struct sh_cmt_info *info;
 117
 118         void __iomem *mapbase;
 119         struct clk *clk;
 120         unsigned long rate;
 121
 122         raw_spinlock_t lock; /* Protect the shared start/stop register */
 123
 124         struct sh_cmt_channel *channels;
 125         unsigned int num_channels;
 126         unsigned int hw_channels;
 127
 128         bool has_clockevent;
 129         bool has_clocksource;
 130 };
 131
 132 #define SH_CMT16_CMCSR_CMF              (1 << 7)
 133 #define SH_CMT16_CMCSR_CMIE             (1 << 6)
 134 #define SH_CMT16_CMCSR_CKS8             (0 << 0)
 135 #define SH_CMT16_CMCSR_CKS32            (1 << 0)
 136 #define SH_CMT16_CMCSR_CKS128           (2 << 0)
 137 #define SH_CMT16_CMCSR_CKS512           (3 << 0)
 138 #define SH_CMT16_CMCSR_CKS_MASK         (3 << 0)
 139
 140 #define SH_CMT32_CMCSR_CMF              (1 << 15)
 141 #define SH_CMT32_CMCSR_OVF              (1 << 14)
 142 #define SH_CMT32_CMCSR_WRFLG            (1 << 13)
 143 #define SH_CMT32_CMCSR_STTF             (1 << 12)
 144 #define SH_CMT32_CMCSR_STPF             (1 << 11)
 145 #define SH_CMT32_CMCSR_SSIE             (1 << 10)
 146 #define SH_CMT32_CMCSR_CMS              (1 << 9)
 147 #define SH_CMT32_CMCSR_CMM              (1 << 8)
 148 #define SH_CMT32_CMCSR_CMTOUT_IE        (1 << 7)
 149 #define SH_CMT32_CMCSR_CMR_NONE         (0 << 4)
 150 #define SH_CMT32_CMCSR_CMR_DMA          (1 << 4)
 151 #define SH_CMT32_CMCSR_CMR_IRQ          (2 << 4)
 152 #define SH_CMT32_CMCSR_CMR_MASK         (3 << 4)
 153 #define SH_CMT32_CMCSR_DBGIVD           (1 << 3)
 154 #define SH_CMT32_CMCSR_CKS_RCLK8        (4 << 0)
 155 #define SH_CMT32_CMCSR_CKS_RCLK32       (5 << 0)
 156 #define SH_CMT32_CMCSR_CKS_RCLK128      (6 << 0)
 157 #define SH_CMT32_CMCSR_CKS_RCLK1        (7 << 0)
 158 #define SH_CMT32_CMCSR_CKS_MASK         (7 << 0)
 159
 160 static unsigned long sh_cmt_read16(void __iomem *base, unsigned long offs)
 161 {
 162         return ioread16(base + (offs << 1));
 163 }
 164
 165 static unsigned long sh_cmt_read32(void __iomem *base, unsigned long offs)
 166 {
 167         return ioread32(base + (offs << 2));
 168 }
 169
 170 static void sh_cmt_write16(void __iomem *base, unsigned long offs,
 171                            unsigned long value)
 172 {
 173         iowrite16(value, base + (offs << 1));
 174 }
 175
 176 static void sh_cmt_write32(void __iomem *base, unsigned long offs,
 177                            unsigned long value)
 178 {
 179         iowrite32(value, base + (offs << 2));
 180 }
 181
 182 static const struct sh_cmt_info sh_cmt_info[] = {
 183         [SH_CMT_16BIT] = {
 184                 .model = SH_CMT_16BIT,
 185                 .width = 16,
 186                 .overflow_bit = SH_CMT16_CMCSR_CMF,
 187                 .clear_bits = ~SH_CMT16_CMCSR_CMF,
 188                 .read_control = sh_cmt_read16,
 189                 .write_control = sh_cmt_write16,
 190                 .read_count = sh_cmt_read16,
 191                 .write_count = sh_cmt_write16,
 192         },
 193         [SH_CMT_32BIT] = {
 194                 .model = SH_CMT_32BIT,
 195                 .width = 32,
 196                 .overflow_bit = SH_CMT32_CMCSR_CMF,
 197                 .clear_bits = ~(SH_CMT32_CMCSR_CMF | SH_CMT32_CMCSR_OVF),
 198                 .read_control = sh_cmt_read16,
 199                 .write_control = sh_cmt_write16,
 200                 .read_count = sh_cmt_read32,
 201                 .write_count = sh_cmt_write32,
 202         },
 203         [SH_CMT_32BIT_FAST] = {
 204                 .model = SH_CMT_32BIT_FAST,
 205                 .width = 32,
 206                 .overflow_bit = SH_CMT32_CMCSR_CMF,
 207                 .clear_bits = ~(SH_CMT32_CMCSR_CMF | SH_CMT32_CMCSR_OVF),
 208                 .read_control = sh_cmt_read16,
 209                 .write_control = sh_cmt_write16,
 210                 .read_count = sh_cmt_read32,
 211                 .write_count = sh_cmt_write32,
 212         },
 213         [SH_CMT_48BIT] = {
 214                 .model = SH_CMT_48BIT,
 215                 .width = 32,
 216                 .overflow_bit = SH_CMT32_CMCSR_CMF,
 217                 .clear_bits = ~(SH_CMT32_CMCSR_CMF | SH_CMT32_CMCSR_OVF),
 218                 .read_control = sh_cmt_read32,
 219                 .write_control = sh_cmt_write32,
 220                 .read_count = sh_cmt_read32,
 221                 .write_count = sh_cmt_write32,
 222         },
 223         [SH_CMT_48BIT_GEN2] = {
 224                 .model = SH_CMT_48BIT_GEN2,
 225                 .width = 32,
 226                 .overflow_bit = SH_CMT32_CMCSR_CMF,
 227                 .clear_bits = ~(SH_CMT32_CMCSR_CMF | SH_CMT32_CMCSR_OVF),
 228                 .read_control = sh_cmt_read32,
 229                 .write_control = sh_cmt_write32,
 230                 .read_count = sh_cmt_read32,
 231                 .write_count = sh_cmt_write32,
 232         },
 233 };
 234
 235 #define CMCSR 0 /* channel register */
 236 #define CMCNT 1 /* channel register */
 237 #define CMCOR 2 /* channel register */
 238
 239 static inline unsigned long sh_cmt_read_cmstr(struct sh_cmt_channel *ch)
 240 {
 241         if (ch->iostart)
 242                 return ch->cmt->info->read_control(ch->iostart, 0);
 243         else
 244                 return ch->cmt->info->read_control(ch->cmt->mapbase, 0);
 245 }
 246
 247 static inline void sh_cmt_write_cmstr(struct sh_cmt_channel *ch,
 248                                       unsigned long value)
 249 {
 250         if (ch->iostart)
 251                 ch->cmt->info->write_control(ch->iostart, 0, value);
 252         else
 253                 ch->cmt->info->write_control(ch->cmt->mapbase, 0, value);
 254 }
 255
 256 static inline unsigned long sh_cmt_read_cmcsr(struct sh_cmt_channel *ch)
 257 {
 258         return ch->cmt->info->read_control(ch->ioctrl, CMCSR);
 259 }
 260
 261 static inline void sh_cmt_write_cmcsr(struct sh_cmt_channel *ch,
 262                                       unsigned long value)
 263 {
 264         ch->cmt->info->write_control(ch->ioctrl, CMCSR, value);
 265 }
 266
 267 static inline unsigned long sh_cmt_read_cmcnt(struct sh_cmt_channel *ch)
 268 {
 269         return ch->cmt->info->read_count(ch->ioctrl, CMCNT);
 270 }
 271
 272 static inline void sh_cmt_write_cmcnt(struct sh_cmt_channel *ch,
 273                                       unsigned long value)
 274 {
 275         ch->cmt->info->write_count(ch->ioctrl, CMCNT, value);
 276 }
 277
 278 static inline void sh_cmt_write_cmcor(struct sh_cmt_channel *ch,
 279                                       unsigned long value)
 280 {
 281         ch->cmt->info->write_count(ch->ioctrl, CMCOR, value);
 282 }
 283
 284 static unsigned long sh_cmt_get_counter(struct sh_cmt_channel *ch,
 285                                         int *has_wrapped)
 286 {
 287         unsigned long v1, v2, v3;
 288         int o1, o2;
 289
 290         o1 = sh_cmt_read_cmcsr(ch) & ch->cmt->info->overflow_bit;
 291
 292         /* Make sure the timer value is stable. Stolen from acpi_pm.c */
 293         do {
 294                 o2 = o1;
 295                 v1 = sh_cmt_read_cmcnt(ch);
 296                 v2 = sh_cmt_read_cmcnt(ch);
 297                 v3 = sh_cmt_read_cmcnt(ch);
 298                 o1 = sh_cmt_read_cmcsr(ch) & ch->cmt->info->overflow_bit;
 299         } while (unlikely((o1 != o2) || (v1 > v2 && v1 < v3)
 300                           || (v2 > v3 && v2 < v1) || (v3 > v1 && v3 < v2)));
 301
 302         *has_wrapped = o1;
 303         return v2;
 304 }
 305
 306 static void sh_cmt_start_stop_ch(struct sh_cmt_channel *ch, int start)
 307 {
 308         unsigned long flags, value;
 309
 310         /* start stop register shared by multiple timer channels */
 311         raw_spin_lock_irqsave(&ch->cmt->lock, flags);
 312         value = sh_cmt_read_cmstr(ch);
 313
 314         if (start)
 315                 value |= 1 << ch->timer_bit;
 316         else
 317                 value &= ~(1 << ch->timer_bit);
 318
 319         sh_cmt_write_cmstr(ch, value);
 320         raw_spin_unlock_irqrestore(&ch->cmt->lock, flags);
 321 }
 322
 323 static int sh_cmt_enable(struct sh_cmt_channel *ch)
 324 {
 325         int k, ret;
 326
 327         pm_runtime_get_sync(&ch->cmt->pdev->dev);
 328         dev_pm_syscore_device(&ch->cmt->pdev->dev, true);
 329
 330         /* enable clock */
 331         ret = clk_enable(ch->cmt->clk);
 332         if (ret) {
 333                 dev_err(&ch->cmt->pdev->dev, "ch%u: cannot enable clock\n",
 334                         ch->index);
 335                 goto err0;
 336         }
 337
 338         /* make sure channel is disabled */
 339         sh_cmt_start_stop_ch(ch, 0);
 340
 341         /* configure channel, periodic mode and maximum timeout */
 342         if (ch->cmt->info->width == 16) {
 343                 sh_cmt_write_cmcsr(ch, SH_CMT16_CMCSR_CMIE |
 344                                    SH_CMT16_CMCSR_CKS512);
 345         } else {
 346                 sh_cmt_write_cmcsr(ch, SH_CMT32_CMCSR_CMM |
 347                                    SH_CMT32_CMCSR_CMTOUT_IE |
 348                                    SH_CMT32_CMCSR_CMR_IRQ |
 349                                    SH_CMT32_CMCSR_CKS_RCLK8);
 350         }
 351
 352         sh_cmt_write_cmcor(ch, 0xffffffff);
 353         sh_cmt_write_cmcnt(ch, 0);
 354
 355         /*
 356          * According to the sh73a0 user's manual, as CMCNT can be operated
 357          * only by the RCLK (Pseudo 32 KHz), there's one restriction on
 358          * modifying CMCNT register; two RCLK cycles are necessary before
 359          * this register is either read or any modification of the value
 360          * it holds is reflected in the LSI's actual operation.
 361          *
 362          * While at it, we're supposed to clear out the CMCNT as of this
 363          * moment, so make sure it's processed properly here.  This will
 364          * take RCLKx2 at maximum.
 365          */
 366         for (k = 0; k < 100; k++) {
 367                 if (!sh_cmt_read_cmcnt(ch))
 368                         break;
 369                 udelay(1);
 370         }
 371
 372         if (sh_cmt_read_cmcnt(ch)) {
 373                 dev_err(&ch->cmt->pdev->dev, "ch%u: cannot clear CMCNT\n",
 374                         ch->index);
 375                 ret = -ETIMEDOUT;
 376                 goto err1;
 377         }
 378
 379         /* enable channel */
 380         sh_cmt_start_stop_ch(ch, 1);
 381         return 0;
 382  err1:
 383         /* stop clock */
 384         clk_disable(ch->cmt->clk);
 385
 386  err0:
 387         return ret;
 388 }
 389
 390 static void sh_cmt_disable(struct sh_cmt_channel *ch)
 391 {
 392         /* disable channel */
 393         sh_cmt_start_stop_ch(ch, 0);
 394
 395         /* disable interrupts in CMT block */
 396         sh_cmt_write_cmcsr(ch, 0);
 397
 398         /* stop clock */
 399         clk_disable(ch->cmt->clk);
 400
 401         dev_pm_syscore_device(&ch->cmt->pdev->dev, false);
 402         pm_runtime_put(&ch->cmt->pdev->dev);
 403 }
 404
 405 /* private flags */
 406 #define FLAG_CLOCKEVENT (1 << 0)
 407 #define FLAG_CLOCKSOURCE (1 << 1)
 408 #define FLAG_REPROGRAM (1 << 2)
 409 #define FLAG_SKIPEVENT (1 << 3)
 410 #define FLAG_IRQCONTEXT (1 << 4)
 411
 412 static void sh_cmt_clock_event_program_verify(struct sh_cmt_channel *ch,
 413                                               int absolute)
 414 {
 415         unsigned long new_match;
 416         unsigned long value = ch->next_match_value;
 417         unsigned long delay = 0;
 418         unsigned long now = 0;
 419         int has_wrapped;
 420
 421         now = sh_cmt_get_counter(ch, &has_wrapped);
 422         ch->flags |= FLAG_REPROGRAM; /* force reprogram */
 423
 424         if (has_wrapped) {
 425                 /* we're competing with the interrupt handler.
 426                  *  -> let the interrupt handler reprogram the timer.
 427                  *  -> interrupt number two handles the event.
 428                  */
 429                 ch->flags |= FLAG_SKIPEVENT;
 430                 return;
 431         }
 432
 433         if (absolute)
 434                 now = 0;
 435
 436         do {
 437                 /* reprogram the timer hardware,
 438                  * but don't save the new match value yet.
 439                  */
 440                 new_match = now + value + delay;
 441                 if (new_match > ch->max_match_value)
 442                         new_match = ch->max_match_value;
 443
 444                 sh_cmt_write_cmcor(ch, new_match);
 445
 446                 now = sh_cmt_get_counter(ch, &has_wrapped);
 447                 if (has_wrapped && (new_match > ch->match_value)) {
 448                         /* we are changing to a greater match value,
 449                          * so this wrap must be caused by the counter
 450                          * matching the old value.
 451                          * -> first interrupt reprograms the timer.
 452                          * -> interrupt number two handles the event.
 453                          */
 454                         ch->flags |= FLAG_SKIPEVENT;
 455                         break;
 456                 }
 457
 458                 if (has_wrapped) {
 459                         /* we are changing to a smaller match value,
 460                          * so the wrap must be caused by the counter
 461                          * matching the new value.
 462                          * -> save programmed match value.
 463                          * -> let isr handle the event.
 464                          */
 465                         ch->match_value = new_match;
 466                         break;
 467                 }
 468
 469                 /* be safe: verify hardware settings */
 470                 if (now < new_match) {
 471                         /* timer value is below match value, all good.
 472                          * this makes sure we won't miss any match events.
 473                          * -> save programmed match value.
 474                          * -> let isr handle the event.
 475                          */
 476                         ch->match_value = new_match;
 477                         break;
 478                 }
 479
 480                 /* the counter has reached a value greater
 481                  * than our new match value. and since the
 482                  * has_wrapped flag isn't set we must have
 483                  * programmed a too close event.
 484                  * -> increase delay and retry.
 485                  */
 486                 if (delay)
 487                         delay <<= 1;
 488                 else
 489                         delay = 1;
 490
 491                 if (!delay)
 492                         dev_warn(&ch->cmt->pdev->dev, "ch%u: too long delay\n",
 493                                  ch->index);
 494
 495         } while (delay);
 496 }
 497
 498 static void __sh_cmt_set_next(struct sh_cmt_channel *ch, unsigned long delta)
 499 {
 500         if (delta > ch->max_match_value)
 501                 dev_warn(&ch->cmt->pdev->dev, "ch%u: delta out of range\n",
 502                          ch->index);
 503
 504         ch->next_match_value = delta;
 505         sh_cmt_clock_event_program_verify(ch, 0);
 506 }
 507
 508 static void sh_cmt_set_next(struct sh_cmt_channel *ch, unsigned long delta)
 509 {
 510         unsigned long flags;
 511
 512         raw_spin_lock_irqsave(&ch->lock, flags);
 513         __sh_cmt_set_next(ch, delta);
 514         raw_spin_unlock_irqrestore(&ch->lock, flags);
 515 }
 516
 517 static irqreturn_t sh_cmt_interrupt(int irq, void *dev_id)
 518 {
 519         struct sh_cmt_channel *ch = dev_id;
 520
 521         /* clear flags */
 522         sh_cmt_write_cmcsr(ch, sh_cmt_read_cmcsr(ch) &
 523                            ch->cmt->info->clear_bits);
 524
 525         /* update clock source counter to begin with if enabled
 526          * the wrap flag should be cleared by the timer specific
 527          * isr before we end up here.
 528          */
 529         if (ch->flags & FLAG_CLOCKSOURCE)
 530                 ch->total_cycles += ch->match_value + 1;
 531
 532         if (!(ch->flags & FLAG_REPROGRAM))
 533                 ch->next_match_value = ch->max_match_value;
 534
 535         ch->flags |= FLAG_IRQCONTEXT;
 536
 537         if (ch->flags & FLAG_CLOCKEVENT) {
 538                 if (!(ch->flags & FLAG_SKIPEVENT)) {
 539                         if (clockevent_state_oneshot(&ch->ced)) {
 540                                 ch->next_match_value = ch->max_match_value;
 541                                 ch->flags |= FLAG_REPROGRAM;
 542                         }
 543
 544                         ch->ced.event_handler(&ch->ced);
 545                 }
 546         }
 547
 548         ch->flags &= ~FLAG_SKIPEVENT;
 549
 550         if (ch->flags & FLAG_REPROGRAM) {
 551                 ch->flags &= ~FLAG_REPROGRAM;
 552                 sh_cmt_clock_event_program_verify(ch, 1);
 553
 554                 if (ch->flags & FLAG_CLOCKEVENT)
 555                         if ((clockevent_state_shutdown(&ch->ced))
 556                             || (ch->match_value == ch->next_match_value))
 557                                 ch->flags &= ~FLAG_REPROGRAM;
 558         }
 559
 560         ch->flags &= ~FLAG_IRQCONTEXT;
 561
 562         return IRQ_HANDLED;
 563 }
 564
 565 static int sh_cmt_start(struct sh_cmt_channel *ch, unsigned long flag)
 566 {
 567         int ret = 0;
 568         unsigned long flags;
 569
 570         raw_spin_lock_irqsave(&ch->lock, flags);
 571
 572         if (!(ch->flags & (FLAG_CLOCKEVENT | FLAG_CLOCKSOURCE)))
 573                 ret = sh_cmt_enable(ch);
 574
 575         if (ret)
 576                 goto out;
 577         ch->flags |= flag;
 578
 579         /* setup timeout if no clockevent */
 580         if ((flag == FLAG_CLOCKSOURCE) && (!(ch->flags & FLAG_CLOCKEVENT)))
 581                 __sh_cmt_set_next(ch, ch->max_match_value);
 582  out:
 583         raw_spin_unlock_irqrestore(&ch->lock, flags);
 584
 585         return ret;
 586 }
 587
 588 static void sh_cmt_stop(struct sh_cmt_channel *ch, unsigned long flag)
 589 {
 590         unsigned long flags;
 591         unsigned long f;
 592
 593         raw_spin_lock_irqsave(&ch->lock, flags);
 594
 595         f = ch->flags & (FLAG_CLOCKEVENT | FLAG_CLOCKSOURCE);
 596         ch->flags &= ~flag;
 597
 598         if (f && !(ch->flags & (FLAG_CLOCKEVENT | FLAG_CLOCKSOURCE)))
 599                 sh_cmt_disable(ch);
 600
 601         /* adjust the timeout to maximum if only clocksource left */
 602         if ((flag == FLAG_CLOCKEVENT) && (ch->flags & FLAG_CLOCKSOURCE))
 603                 __sh_cmt_set_next(ch, ch->max_match_value);
 604
 605         raw_spin_unlock_irqrestore(&ch->lock, flags);
 606 }
 607
 608 static struct sh_cmt_channel *cs_to_sh_cmt(struct clocksource *cs)
 609 {
 610         return container_of(cs, struct sh_cmt_channel, cs);
 611 }
 612
 613 static u64 sh_cmt_clocksource_read(struct clocksource *cs)
 614 {
 615         struct sh_cmt_channel *ch = cs_to_sh_cmt(cs);
 616         unsigned long flags, raw;
 617         unsigned long value;
 618         int has_wrapped;
 619
 620         raw_spin_lock_irqsave(&ch->lock, flags);
 621         value = ch->total_cycles;
 622         raw = sh_cmt_get_counter(ch, &has_wrapped);
 623
 624         if (unlikely(has_wrapped))
 625                 raw += ch->match_value + 1;
 626         raw_spin_unlock_irqrestore(&ch->lock, flags);
 627
 628         return value + raw;
 629 }
 630
 631 static int sh_cmt_clocksource_enable(struct clocksource *cs)
 632 {
 633         int ret;
 634         struct sh_cmt_channel *ch = cs_to_sh_cmt(cs);
 635
 636         WARN_ON(ch->cs_enabled);
 637
 638         ch->total_cycles = 0;
 639
 640         ret = sh_cmt_start(ch, FLAG_CLOCKSOURCE);
 641         if (!ret)
 642                 ch->cs_enabled = true;
 643
 644         return ret;
 645 }
 646
 647 static void sh_cmt_clocksource_disable(struct clocksource *cs)
 648 {
 649         struct sh_cmt_channel *ch = cs_to_sh_cmt(cs);
 650
 651         WARN_ON(!ch->cs_enabled);
 652
 653         sh_cmt_stop(ch, FLAG_CLOCKSOURCE);
 654         ch->cs_enabled = false;
 655 }
 656
 657 static void sh_cmt_clocksource_suspend(struct clocksource *cs)
 658 {
 659         struct sh_cmt_channel *ch = cs_to_sh_cmt(cs);
 660
 661         if (!ch->cs_enabled)
 662                 return;
 663
 664         sh_cmt_stop(ch, FLAG_CLOCKSOURCE);
 665         pm_genpd_syscore_poweroff(&ch->cmt->pdev->dev);
 666 }
 667
 668 static void sh_cmt_clocksource_resume(struct clocksource *cs)
 669 {
 670         struct sh_cmt_channel *ch = cs_to_sh_cmt(cs);
 671
 672         if (!ch->cs_enabled)
 673                 return;
 674
 675         pm_genpd_syscore_poweron(&ch->cmt->pdev->dev);
 676         sh_cmt_start(ch, FLAG_CLOCKSOURCE);
 677 }
 678
 679 static int sh_cmt_register_clocksource(struct sh_cmt_channel *ch,
 680                                        const char *name)
 681 {
 682         struct clocksource *cs = &ch->cs;
 683
 684         cs->name = name;
 685         cs->rating = 125;
 686         cs->read = sh_cmt_clocksource_read;
 687         cs->enable = sh_cmt_clocksource_enable;
 688         cs->disable = sh_cmt_clocksource_disable;
 689         cs->suspend = sh_cmt_clocksource_suspend;
 690         cs->resume = sh_cmt_clocksource_resume;
 691         cs->mask = CLOCKSOURCE_MASK(sizeof(unsigned long) * 8);
 692         cs->flags = CLOCK_SOURCE_IS_CONTINUOUS;
 693
 694         dev_info(&ch->cmt->pdev->dev, "ch%u: used as clock source\n",
 695                  ch->index);
 696
 697         clocksource_register_hz(cs, ch->cmt->rate);
 698         return 0;
 699 }
 700
 701 static struct sh_cmt_channel *ced_to_sh_cmt(struct clock_event_device *ced)
 702 {
 703         return container_of(ced, struct sh_cmt_channel, ced);
 704 }
 705
 706 static void sh_cmt_clock_event_start(struct sh_cmt_channel *ch, int periodic)
 707 {
 708         sh_cmt_start(ch, FLAG_CLOCKEVENT);
 709
 710         if (periodic)
 711                 sh_cmt_set_next(ch, ((ch->cmt->rate + HZ/2) / HZ) - 1);
 712         else
 713                 sh_cmt_set_next(ch, ch->max_match_value);
 714 }
 715
 716 static int sh_cmt_clock_event_shutdown(struct clock_event_device *ced)
 717 {
 718         struct sh_cmt_channel *ch = ced_to_sh_cmt(ced);
 719
 720         sh_cmt_stop(ch, FLAG_CLOCKEVENT);
 721         return 0;
 722 }
 723
 724 static int sh_cmt_clock_event_set_state(struct clock_event_device *ced,
 725                                         int periodic)
 726 {
 727         struct sh_cmt_channel *ch = ced_to_sh_cmt(ced);
 728
 729         /* deal with old setting first */
 730         if (clockevent_state_oneshot(ced) || clockevent_state_periodic(ced))
 731                 sh_cmt_stop(ch, FLAG_CLOCKEVENT);
 732
 733         dev_info(&ch->cmt->pdev->dev, "ch%u: used for %s clock events\n",
 734                  ch->index, periodic ? "periodic" : "oneshot");
 735         sh_cmt_clock_event_start(ch, periodic);
 736         return 0;
 737 }
 738
 739 static int sh_cmt_clock_event_set_oneshot(struct clock_event_device *ced)
 740 {
 741         return sh_cmt_clock_event_set_state(ced, 0);
 742 }
 743
 744 static int sh_cmt_clock_event_set_periodic(struct clock_event_device *ced)
 745 {
 746         return sh_cmt_clock_event_set_state(ced, 1);
 747 }
 748
 749 static int sh_cmt_clock_event_next(unsigned long delta,
 750                                    struct clock_event_device *ced)
 751 {
 752         struct sh_cmt_channel *ch = ced_to_sh_cmt(ced);
 753
 754         BUG_ON(!clockevent_state_oneshot(ced));
 755         if (likely(ch->flags & FLAG_IRQCONTEXT))
 756                 ch->next_match_value = delta - 1;
 757         else
 758                 sh_cmt_set_next(ch, delta - 1);
 759
 760         return 0;
 761 }
 762
 763 static void sh_cmt_clock_event_suspend(struct clock_event_device *ced)
 764 {
 765         struct sh_cmt_channel *ch = ced_to_sh_cmt(ced);
 766
 767         pm_genpd_syscore_poweroff(&ch->cmt->pdev->dev);
 768         clk_unprepare(ch->cmt->clk);
 769 }
 770
 771 static void sh_cmt_clock_event_resume(struct clock_event_device *ced)
 772 {
 773         struct sh_cmt_channel *ch = ced_to_sh_cmt(ced);
 774
 775         clk_prepare(ch->cmt->clk);
 776         pm_genpd_syscore_poweron(&ch->cmt->pdev->dev);
 777 }
 778
 779 static int sh_cmt_register_clockevent(struct sh_cmt_channel *ch,
 780                                       const char *name)
 781 {
 782         struct clock_event_device *ced = &ch->ced;
 783         int irq;
 784         int ret;
 785
 786         irq = platform_get_irq(ch->cmt->pdev, ch->index);
 787         if (irq < 0) {
 788                 dev_err(&ch->cmt->pdev->dev, "ch%u: failed to get irq\n",
 789                         ch->index);
 790                 return irq;
 791         }
 792
 793         ret = request_irq(irq, sh_cmt_interrupt,
 794                           IRQF_TIMER | IRQF_IRQPOLL | IRQF_NOBALANCING,
 795                           dev_name(&ch->cmt->pdev->dev), ch);
 796         if (ret) {
 797                 dev_err(&ch->cmt->pdev->dev, "ch%u: failed to request irq %d\n",
 798                         ch->index, irq);
 799                 return ret;
 800         }
 801
 802         ced->name = name;
 803         ced->features = CLOCK_EVT_FEAT_PERIODIC;
 804         ced->features |= CLOCK_EVT_FEAT_ONESHOT;
 805         ced->rating = 125;
 806         ced->cpumask = cpu_possible_mask;
 807         ced->set_next_event = sh_cmt_clock_event_next;
 808         ced->set_state_shutdown = sh_cmt_clock_event_shutdown;
 809         ced->set_state_periodic = sh_cmt_clock_event_set_periodic;
 810         ced->set_state_oneshot = sh_cmt_clock_event_set_oneshot;
 811         ced->suspend = sh_cmt_clock_event_suspend;
 812         ced->resume = sh_cmt_clock_event_resume;
 813
 814         /* TODO: calculate good shift from rate and counter bit width */
 815         ced->shift = 32;
 816         ced->mult = div_sc(ch->cmt->rate, NSEC_PER_SEC, ced->shift);
 817         ced->max_delta_ns = clockevent_delta2ns(ch->max_match_value, ced);
 818         ced->min_delta_ns = clockevent_delta2ns(0x1f, ced);
 819
 820         dev_info(&ch->cmt->pdev->dev, "ch%u: used for clock events\n",
 821                  ch->index);
 822         clockevents_register_device(ced);
 823
 824         return 0;
 825 }
 826
 827 static int sh_cmt_register(struct sh_cmt_channel *ch, const char *name,
 828                            bool clockevent, bool clocksource)
 829 {
 830         int ret;
 831
 832         if (clockevent) {
 833                 ch->cmt->has_clockevent = true;
 834                 ret = sh_cmt_register_clockevent(ch, name);
 835                 if (ret < 0)
 836                         return ret;
 837         }
 838
 839         if (clocksource) {
 840                 ch->cmt->has_clocksource = true;
 841                 sh_cmt_register_clocksource(ch, name);
 842         }
 843
 844         return 0;
 845 }
 846
 847 static int sh_cmt_setup_channel(struct sh_cmt_channel *ch, unsigned int index,
 848                                 unsigned int hwidx, bool clockevent,
 849                                 bool clocksource, struct sh_cmt_device *cmt)
 850 {
 851         int ret;
 852
 853         /* Skip unused channels. */
 854         if (!clockevent && !clocksource)
 855                 return 0;
 856
 857         ch->cmt = cmt;
 858         ch->index = index;
 859         ch->hwidx = hwidx;
 860
 861         /*
 862          * Compute the address of the channel control register block. For the
 863          * timers with a per-channel start/stop register, compute its address
 864          * as well.
 865          */
 866         switch (cmt->info->model) {
 867         case SH_CMT_16BIT:
 868                 ch->ioctrl = cmt->mapbase + 2 + ch->hwidx * 6;
 869                 break;
 870         case SH_CMT_32BIT:
 871         case SH_CMT_48BIT:
 872                 ch->ioctrl = cmt->mapbase + 0x10 + ch->hwidx * 0x10;
 873                 break;
 874         case SH_CMT_32BIT_FAST:
 875                 /*
 876                  * The 32-bit "fast" timer has a single channel at hwidx 5 but
 877                  * is located at offset 0x40 instead of 0x60 for some reason.
 878                  */
 879                 ch->ioctrl = cmt->mapbase + 0x40;
 880                 break;
 881         case SH_CMT_48BIT_GEN2:
 882                 ch->iostart = cmt->mapbase + ch->hwidx * 0x100;
 883                 ch->ioctrl = ch->iostart + 0x10;
 884                 break;
 885         }
 886
 887         if (cmt->info->width == (sizeof(ch->max_match_value) * 8))
 888                 ch->max_match_value = ~0;
 889         else
 890                 ch->max_match_value = (1 << cmt->info->width) - 1;
 891
 892         ch->match_value = ch->max_match_value;
 893         raw_spin_lock_init(&ch->lock);
 894
 895         ch->timer_bit = cmt->info->model == SH_CMT_48BIT_GEN2 ? 0 : ch->hwidx;
 896
 897         ret = sh_cmt_register(ch, dev_name(&cmt->pdev->dev),
 898                               clockevent, clocksource);
 899         if (ret) {
 900                 dev_err(&cmt->pdev->dev, "ch%u: registration failed\n",
 901                         ch->index);
 902                 return ret;
 903         }
 904         ch->cs_enabled = false;
 905
 906         return 0;
 907 }
 908
 909 static int sh_cmt_map_memory(struct sh_cmt_device *cmt)
 910 {
 911         struct resource *mem;
 912
 913         mem = platform_get_resource(cmt->pdev, IORESOURCE_MEM, 0);
 914         if (!mem) {
 915                 dev_err(&cmt->pdev->dev, "failed to get I/O memory\n");
 916                 return -ENXIO;
 917         }
 918
 919         cmt->mapbase = ioremap_nocache(mem->start, resource_size(mem));
 920         if (cmt->mapbase == NULL) {
 921                 dev_err(&cmt->pdev->dev, "failed to remap I/O memory\n");
 922                 return -ENXIO;
 923         }
 924
 925         return 0;
 926 }
 927
 928 static const struct platform_device_id sh_cmt_id_table[] = {
 929         { "sh-cmt-16", (kernel_ulong_t)&sh_cmt_info[SH_CMT_16BIT] },
 930         { "sh-cmt-32", (kernel_ulong_t)&sh_cmt_info[SH_CMT_32BIT] },
 931         { }
 932 };
 933 MODULE_DEVICE_TABLE(platform, sh_cmt_id_table);
 934
 935 static const struct of_device_id sh_cmt_of_table[] __maybe_unused = {
 936         { .compatible = "renesas,cmt-32", .data = &sh_cmt_info[SH_CMT_32BIT] },
 937         { .compatible = "renesas,cmt-32-fast", .data = &sh_cmt_info[SH_CMT_32BIT_FAST] },
 938         { .compatible = "renesas,cmt-48", .data = &sh_cmt_info[SH_CMT_48BIT] },
 939         { .compatible = "renesas,cmt-48-gen2", .data = &sh_cmt_info[SH_CMT_48BIT_GEN2] },
 940         { }
 941 };
 942 MODULE_DEVICE_TABLE(of, sh_cmt_of_table);
 943
 944 static int sh_cmt_parse_dt(struct sh_cmt_device *cmt)
 945 {
 946         struct device_node *np = cmt->pdev->dev.of_node;
 947
 948         return of_property_read_u32(np, "renesas,channels-mask",
 949                                     &cmt->hw_channels);
 950 }
 951
 952 static int sh_cmt_setup(struct sh_cmt_device *cmt, struct platform_device *pdev)
 953 {
 954         unsigned int mask;
 955         unsigned int i;
 956         int ret;
 957
 958         cmt->pdev = pdev;
 959         raw_spin_lock_init(&cmt->lock);
 960
 961         if (IS_ENABLED(CONFIG_OF) && pdev->dev.of_node) {
 962                 const struct of_device_id *id;
 963
 964                 id = of_match_node(sh_cmt_of_table, pdev->dev.of_node);
 965                 cmt->info = id->data;
 966
 967                 ret = sh_cmt_parse_dt(cmt);
 968                 if (ret < 0)
 969                         return ret;
 970         } else if (pdev->dev.platform_data) {
 971                 struct sh_timer_config *cfg = pdev->dev.platform_data;
 972                 const struct platform_device_id *id = pdev->id_entry;
 973
 974                 cmt->info = (const struct sh_cmt_info *)id->driver_data;
 975                 cmt->hw_channels = cfg->channels_mask;
 976         } else {
 977                 dev_err(&cmt->pdev->dev, "missing platform data\n");
 978                 return -ENXIO;
 979         }
 980
 981         /* Get hold of clock. */
 982         cmt->clk = clk_get(&cmt->pdev->dev, "fck");
 983         if (IS_ERR(cmt->clk)) {
 984                 dev_err(&cmt->pdev->dev, "cannot get clock\n");
 985                 return PTR_ERR(cmt->clk);
 986         }
 987
 988         ret = clk_prepare(cmt->clk);
 989         if (ret < 0)
 990                 goto err_clk_put;
 991
 992         /* Determine clock rate. */
 993         ret = clk_enable(cmt->clk);
 994         if (ret < 0)
 995                 goto err_clk_unprepare;
 996
 997         if (cmt->info->width == 16)
 998                 cmt->rate = clk_get_rate(cmt->clk) / 512;
 999         else
1000                 cmt->rate = clk_get_rate(cmt->clk) / 8;
1001
1002         clk_disable(cmt->clk);
1003
1004         /* Map the memory resource(s). */
1005         ret = sh_cmt_map_memory(cmt);
1006         if (ret < 0)
1007                 goto err_clk_unprepare;
1008
1009         /* Allocate and setup the channels. */
1010         cmt->num_channels = hweight8(cmt->hw_channels);
1011         cmt->channels = kzalloc(cmt->num_channels * sizeof(*cmt->channels),
1012                                 GFP_KERNEL);
1013         if (cmt->channels == NULL) {
1014                 ret = -ENOMEM;
1015                 goto err_unmap;
1016         }
1017
1018         /*
1019          * Use the first channel as a clock event device and the second channel
1020          * as a clock source. If only one channel is available use it for both.
1021          */
1022         for (i = 0, mask = cmt->hw_channels; i < cmt->num_channels; ++i) {
1023                 unsigned int hwidx = ffs(mask) - 1;
1024                 bool clocksource = i == 1 || cmt->num_channels == 1;
1025                 bool clockevent = i == 0;
1026
1027                 ret = sh_cmt_setup_channel(&cmt->channels[i], i, hwidx,
1028                                            clockevent, clocksource, cmt);
1029                 if (ret < 0)
1030                         goto err_unmap;
1031
1032                 mask &= ~(1 << hwidx);
1033         }
1034
1035         platform_set_drvdata(pdev, cmt);
1036
1037         return 0;
1038
1039 err_unmap:
1040         kfree(cmt->channels);
1041         iounmap(cmt->mapbase);
1042 err_clk_unprepare:
1043         clk_unprepare(cmt->clk);
1044 err_clk_put:
1045         clk_put(cmt->clk);
1046         return ret;
1047 }
1048
1049 static int sh_cmt_probe(struct platform_device *pdev)
1050 {
1051         struct sh_cmt_device *cmt = platform_get_drvdata(pdev);
1052         int ret;
1053
1054         if (!is_early_platform_device(pdev)) {
1055                 pm_runtime_set_active(&pdev->dev);
1056                 pm_runtime_enable(&pdev->dev);
1057         }
1058
1059         if (cmt) {
1060                 dev_info(&pdev->dev, "kept as earlytimer\n");
1061                 goto out;
1062         }
1063
1064         cmt = kzalloc(sizeof(*cmt), GFP_KERNEL);
1065         if (cmt == NULL)
1066                 return -ENOMEM;
1067
1068         ret = sh_cmt_setup(cmt, pdev);
1069         if (ret) {
1070                 kfree(cmt);
1071                 pm_runtime_idle(&pdev->dev);
1072                 return ret;
1073         }
1074         if (is_early_platform_device(pdev))
1075                 return 0;
1076
1077  out:
1078         if (cmt->has_clockevent || cmt->has_clocksource)
1079                 pm_runtime_irq_safe(&pdev->dev);
1080         else
1081                 pm_runtime_idle(&pdev->dev);
1082
1083         return 0;
1084 }
1085
1086 static int sh_cmt_remove(struct platform_device *pdev)
1087 {
1088         return -EBUSY; /* cannot unregister clockevent and clocksource */
1089 }
1090
1091 static struct platform_driver sh_cmt_device_driver = {
1092         .probe          = sh_cmt_probe,
1093         .remove         = sh_cmt_remove,
1094         .driver         = {
1095                 .name   = "sh_cmt",
1096                 .of_match_table = of_match_ptr(sh_cmt_of_table),
1097         },
1098         .id_table       = sh_cmt_id_table,
1099 };
1100
1101 static int __init sh_cmt_init(void)
1102 {
1103         return platform_driver_register(&sh_cmt_device_driver);
1104 }
1105
1106 static void __exit sh_cmt_exit(void)
1107 {
1108         platform_driver_unregister(&sh_cmt_device_driver);
1109 }
1110
1111 early_platform_init("earlytimer", &sh_cmt_device_driver);
1112 subsys_initcall(sh_cmt_init);
1113 module_exit(sh_cmt_exit);
1114
1115 MODULE_AUTHOR("Magnus Damm");
1116 MODULE_DESCRIPTION("SuperH CMT Timer Driver");
1117 MODULE_LICENSE("GPL v2");