drivers/clocksource/timer-fttmr010.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Faraday Technology FTTMR010 timer driver
   4  * Copyright (C) 2017 Linus Walleij <linus.walleij@linaro.org>
   5  *
   6  * Based on a rewrite of arch/arm/mach-gemini/timer.c:
   7  * Copyright (C) 2001-2006 Storlink, Corp.
   8  * Copyright (C) 2008-2009 Paulius Zaleckas <paulius.zaleckas@teltonika.lt>
   9  */
  10 #include <linux/interrupt.h>
  11 #include <linux/io.h>
  12 #include <linux/of.h>
  13 #include <linux/of_address.h>
  14 #include <linux/of_irq.h>
  15 #include <linux/clockchips.h>
  16 #include <linux/clocksource.h>
  17 #include <linux/sched_clock.h>
  18 #include <linux/clk.h>
  19 #include <linux/slab.h>
  20 #include <linux/bitops.h>
  21 #include <linux/delay.h>
  22
  23 /*
  24  * Register definitions common for all the timer variants.
  25  */
  26 #define TIMER1_COUNT            (0x00)
  27 #define TIMER1_LOAD             (0x04)
  28 #define TIMER1_MATCH1           (0x08)
  29 #define TIMER1_MATCH2           (0x0c)
  30 #define TIMER2_COUNT            (0x10)
  31 #define TIMER2_LOAD             (0x14)
  32 #define TIMER2_MATCH1           (0x18)
  33 #define TIMER2_MATCH2           (0x1c)
  34 #define TIMER3_COUNT            (0x20)
  35 #define TIMER3_LOAD             (0x24)
  36 #define TIMER3_MATCH1           (0x28)
  37 #define TIMER3_MATCH2           (0x2c)
  38 #define TIMER_CR                (0x30)
  39
  40 /*
  41  * Control register set to clear for ast2600 only.
  42  */
  43 #define AST2600_TIMER_CR_CLR    (0x3c)
  44
  45 /*
  46  * Control register (TMC30) bit fields for fttmr010/gemini/moxart timers.
  47  */
  48 #define TIMER_1_CR_ENABLE       BIT(0)
  49 #define TIMER_1_CR_CLOCK        BIT(1)
  50 #define TIMER_1_CR_INT          BIT(2)
  51 #define TIMER_2_CR_ENABLE       BIT(3)
  52 #define TIMER_2_CR_CLOCK        BIT(4)
  53 #define TIMER_2_CR_INT          BIT(5)
  54 #define TIMER_3_CR_ENABLE       BIT(6)
  55 #define TIMER_3_CR_CLOCK        BIT(7)
  56 #define TIMER_3_CR_INT          BIT(8)
  57 #define TIMER_1_CR_UPDOWN       BIT(9)
  58 #define TIMER_2_CR_UPDOWN       BIT(10)
  59 #define TIMER_3_CR_UPDOWN       BIT(11)
  60
  61 /*
  62  * Control register (TMC30) bit fields for aspeed ast2400/ast2500 timers.
  63  * The aspeed timers move bits around in the control register and lacks
  64  * bits for setting the timer to count upwards.
  65  */
  66 #define TIMER_1_CR_ASPEED_ENABLE        BIT(0)
  67 #define TIMER_1_CR_ASPEED_CLOCK         BIT(1)
  68 #define TIMER_1_CR_ASPEED_INT           BIT(2)
  69 #define TIMER_2_CR_ASPEED_ENABLE        BIT(4)
  70 #define TIMER_2_CR_ASPEED_CLOCK         BIT(5)
  71 #define TIMER_2_CR_ASPEED_INT           BIT(6)
  72 #define TIMER_3_CR_ASPEED_ENABLE        BIT(8)
  73 #define TIMER_3_CR_ASPEED_CLOCK         BIT(9)
  74 #define TIMER_3_CR_ASPEED_INT           BIT(10)
  75
  76 /*
  77  * Interrupt status/mask register definitions for fttmr010/gemini/moxart
  78  * timers.
  79  * The registers don't exist and they are not needed on aspeed timers
  80  * because:
  81  *   - aspeed timer overflow interrupt is controlled by bits in Control
  82  *     Register (TMC30).
  83  *   - aspeed timers always generate interrupt when either one of the
  84  *     Match registers equals to Status register.
  85  */
  86 #define TIMER_INTR_STATE        (0x34)
  87 #define TIMER_INTR_MASK         (0x38)
  88 #define TIMER_1_INT_MATCH1      BIT(0)
  89 #define TIMER_1_INT_MATCH2      BIT(1)
  90 #define TIMER_1_INT_OVERFLOW    BIT(2)
  91 #define TIMER_2_INT_MATCH1      BIT(3)
  92 #define TIMER_2_INT_MATCH2      BIT(4)
  93 #define TIMER_2_INT_OVERFLOW    BIT(5)
  94 #define TIMER_3_INT_MATCH1      BIT(6)
  95 #define TIMER_3_INT_MATCH2      BIT(7)
  96 #define TIMER_3_INT_OVERFLOW    BIT(8)
  97 #define TIMER_INT_ALL_MASK      0x1ff
  98
  99 struct fttmr010 {
 100         void __iomem *base;
 101         unsigned int tick_rate;
 102         bool is_aspeed;
 103         u32 t1_enable_val;
 104         struct clock_event_device clkevt;
 105         int (*timer_shutdown)(struct clock_event_device *evt);
 106 #ifdef CONFIG_ARM
 107         struct delay_timer delay_timer;
 108 #endif
 109 };
 110
 111 /*
 112  * A local singleton used by sched_clock and delay timer reads, which are
 113  * fast and stateless
 114  */
 115 static struct fttmr010 *local_fttmr;
 116
 117 static inline struct fttmr010 *to_fttmr010(struct clock_event_device *evt)
 118 {
 119         return container_of(evt, struct fttmr010, clkevt);
 120 }
 121
 122 static unsigned long fttmr010_read_current_timer_up(void)
 123 {
 124         return readl(local_fttmr->base + TIMER2_COUNT);
 125 }
 126
 127 static unsigned long fttmr010_read_current_timer_down(void)
 128 {
 129         return ~readl(local_fttmr->base + TIMER2_COUNT);
 130 }
 131
 132 static u64 notrace fttmr010_read_sched_clock_up(void)
 133 {
 134         return fttmr010_read_current_timer_up();
 135 }
 136
 137 static u64 notrace fttmr010_read_sched_clock_down(void)
 138 {
 139         return fttmr010_read_current_timer_down();
 140 }
 141
 142 static int fttmr010_timer_set_next_event(unsigned long cycles,
 143                                        struct clock_event_device *evt)
 144 {
 145         struct fttmr010 *fttmr010 = to_fttmr010(evt);
 146         u32 cr;
 147
 148         /* Stop */
 149         fttmr010->timer_shutdown(evt);
 150
 151         if (fttmr010->is_aspeed) {
 152                 /*
 153                  * ASPEED Timer Controller will load TIMER1_LOAD register
 154                  * into TIMER1_COUNT register when the timer is re-enabled.
 155                  */
 156                 writel(cycles, fttmr010->base + TIMER1_LOAD);
 157         } else {
 158                 /* Setup the match register forward in time */
 159                 cr = readl(fttmr010->base + TIMER1_COUNT);
 160                 writel(cr + cycles, fttmr010->base + TIMER1_MATCH1);
 161         }
 162
 163         /* Start */
 164         cr = readl(fttmr010->base + TIMER_CR);
 165         cr |= fttmr010->t1_enable_val;
 166         writel(cr, fttmr010->base + TIMER_CR);
 167
 168         return 0;
 169 }
 170
 171 static int ast2600_timer_shutdown(struct clock_event_device *evt)
 172 {
 173         struct fttmr010 *fttmr010 = to_fttmr010(evt);
 174
 175         /* Stop */
 176         writel(fttmr010->t1_enable_val, fttmr010->base + AST2600_TIMER_CR_CLR);
 177
 178         return 0;
 179 }
 180
 181 static int fttmr010_timer_shutdown(struct clock_event_device *evt)
 182 {
 183         struct fttmr010 *fttmr010 = to_fttmr010(evt);
 184         u32 cr;
 185
 186         /* Stop */
 187         cr = readl(fttmr010->base + TIMER_CR);
 188         cr &= ~fttmr010->t1_enable_val;
 189         writel(cr, fttmr010->base + TIMER_CR);
 190
 191         return 0;
 192 }
 193
 194 static int fttmr010_timer_set_oneshot(struct clock_event_device *evt)
 195 {
 196         struct fttmr010 *fttmr010 = to_fttmr010(evt);
 197         u32 cr;
 198
 199         /* Stop */
 200         fttmr010->timer_shutdown(evt);
 201
 202         /* Setup counter start from 0 or ~0 */
 203         writel(0, fttmr010->base + TIMER1_COUNT);
 204         if (fttmr010->is_aspeed) {
 205                 writel(~0, fttmr010->base + TIMER1_LOAD);
 206         } else {
 207                 writel(0, fttmr010->base + TIMER1_LOAD);
 208
 209                 /* Enable interrupt */
 210                 cr = readl(fttmr010->base + TIMER_INTR_MASK);
 211                 cr &= ~(TIMER_1_INT_OVERFLOW | TIMER_1_INT_MATCH2);
 212                 cr |= TIMER_1_INT_MATCH1;
 213                 writel(cr, fttmr010->base + TIMER_INTR_MASK);
 214         }
 215
 216         return 0;
 217 }
 218
 219 static int fttmr010_timer_set_periodic(struct clock_event_device *evt)
 220 {
 221         struct fttmr010 *fttmr010 = to_fttmr010(evt);
 222         u32 period = DIV_ROUND_CLOSEST(fttmr010->tick_rate, HZ);
 223         u32 cr;
 224
 225         /* Stop */
 226         fttmr010->timer_shutdown(evt);
 227
 228         /* Setup timer to fire at 1/HZ intervals. */
 229         if (fttmr010->is_aspeed) {
 230                 writel(period, fttmr010->base + TIMER1_LOAD);
 231         } else {
 232                 cr = 0xffffffff - (period - 1);
 233                 writel(cr, fttmr010->base + TIMER1_COUNT);
 234                 writel(cr, fttmr010->base + TIMER1_LOAD);
 235
 236                 /* Enable interrupt on overflow */
 237                 cr = readl(fttmr010->base + TIMER_INTR_MASK);
 238                 cr &= ~(TIMER_1_INT_MATCH1 | TIMER_1_INT_MATCH2);
 239                 cr |= TIMER_1_INT_OVERFLOW;
 240                 writel(cr, fttmr010->base + TIMER_INTR_MASK);
 241         }
 242
 243         /* Start the timer */
 244         cr = readl(fttmr010->base + TIMER_CR);
 245         cr |= fttmr010->t1_enable_val;
 246         writel(cr, fttmr010->base + TIMER_CR);
 247
 248         return 0;
 249 }
 250
 251 /*
 252  * IRQ handler for the timer
 253  */
 254 static irqreturn_t fttmr010_timer_interrupt(int irq, void *dev_id)
 255 {
 256         struct clock_event_device *evt = dev_id;
 257
 258         evt->event_handler(evt);
 259         return IRQ_HANDLED;
 260 }
 261
 262 static irqreturn_t ast2600_timer_interrupt(int irq, void *dev_id)
 263 {
 264         struct clock_event_device *evt = dev_id;
 265         struct fttmr010 *fttmr010 = to_fttmr010(evt);
 266
 267         writel(0x1, fttmr010->base + TIMER_INTR_STATE);
 268
 269         evt->event_handler(evt);
 270         return IRQ_HANDLED;
 271 }
 272
 273 static int __init fttmr010_common_init(struct device_node *np,
 274                                        bool is_aspeed, bool is_ast2600)
 275 {
 276         struct fttmr010 *fttmr010;
 277         int irq;
 278         struct clk *clk;
 279         int ret;
 280         u32 val;
 281
 282         /*
 283          * These implementations require a clock reference.
 284          * FIXME: we currently only support clocking using PCLK
 285          * and using EXTCLK is not supported in the driver.
 286          */
 287         clk = of_clk_get_by_name(np, "PCLK");
 288         if (IS_ERR(clk)) {
 289                 pr_err("could not get PCLK\n");
 290                 return PTR_ERR(clk);
 291         }
 292         ret = clk_prepare_enable(clk);
 293         if (ret) {
 294                 pr_err("failed to enable PCLK\n");
 295                 return ret;
 296         }
 297
 298         fttmr010 = kzalloc(sizeof(*fttmr010), GFP_KERNEL);
 299         if (!fttmr010) {
 300                 ret = -ENOMEM;
 301                 goto out_disable_clock;
 302         }
 303         fttmr010->tick_rate = clk_get_rate(clk);
 304
 305         fttmr010->base = of_iomap(np, 0);
 306         if (!fttmr010->base) {
 307                 pr_err("Can't remap registers\n");
 308                 ret = -ENXIO;
 309                 goto out_free;
 310         }
 311         /* IRQ for timer 1 */
 312         irq = irq_of_parse_and_map(np, 0);
 313         if (irq <= 0) {
 314                 pr_err("Can't parse IRQ\n");
 315                 ret = -EINVAL;
 316                 goto out_unmap;
 317         }
 318
 319         /*
 320          * The Aspeed timers move bits around in the control register.
 321          */
 322         if (is_aspeed) {
 323                 fttmr010->t1_enable_val = TIMER_1_CR_ASPEED_ENABLE |
 324                         TIMER_1_CR_ASPEED_INT;
 325                 fttmr010->is_aspeed = true;
 326         } else {
 327                 fttmr010->t1_enable_val = TIMER_1_CR_ENABLE | TIMER_1_CR_INT;
 328
 329                 /*
 330                  * Reset the interrupt mask and status
 331                  */
 332                 writel(TIMER_INT_ALL_MASK, fttmr010->base + TIMER_INTR_MASK);
 333                 writel(0, fttmr010->base + TIMER_INTR_STATE);
 334         }
 335
 336         /*
 337          * Enable timer 1 count up, timer 2 count up, except on Aspeed,
 338          * where everything just counts down.
 339          */
 340         if (is_aspeed)
 341                 val = TIMER_2_CR_ASPEED_ENABLE;
 342         else {
 343                 val = TIMER_2_CR_ENABLE | TIMER_1_CR_UPDOWN |
 344                         TIMER_2_CR_UPDOWN;
 345         }
 346         writel(val, fttmr010->base + TIMER_CR);
 347
 348         /*
 349          * Setup free-running clocksource timer (interrupts
 350          * disabled.)
 351          */
 352         local_fttmr = fttmr010;
 353         writel(0, fttmr010->base + TIMER2_COUNT);
 354         writel(0, fttmr010->base + TIMER2_MATCH1);
 355         writel(0, fttmr010->base + TIMER2_MATCH2);
 356
 357         if (fttmr010->is_aspeed) {
 358                 writel(~0, fttmr010->base + TIMER2_LOAD);
 359                 clocksource_mmio_init(fttmr010->base + TIMER2_COUNT,
 360                                       "FTTMR010-TIMER2",
 361                                       fttmr010->tick_rate,
 362                                       300, 32, clocksource_mmio_readl_down);
 363                 sched_clock_register(fttmr010_read_sched_clock_down, 32,
 364                                      fttmr010->tick_rate);
 365         } else {
 366                 writel(0, fttmr010->base + TIMER2_LOAD);
 367                 clocksource_mmio_init(fttmr010->base + TIMER2_COUNT,
 368                                       "FTTMR010-TIMER2",
 369                                       fttmr010->tick_rate,
 370                                       300, 32, clocksource_mmio_readl_up);
 371                 sched_clock_register(fttmr010_read_sched_clock_up, 32,
 372                                      fttmr010->tick_rate);
 373         }
 374
 375         /*
 376          * Setup clockevent timer (interrupt-driven) on timer 1.
 377          */
 378         writel(0, fttmr010->base + TIMER1_COUNT);
 379         writel(0, fttmr010->base + TIMER1_LOAD);
 380         writel(0, fttmr010->base + TIMER1_MATCH1);
 381         writel(0, fttmr010->base + TIMER1_MATCH2);
 382
 383         if (is_ast2600) {
 384                 fttmr010->timer_shutdown = ast2600_timer_shutdown;
 385                 ret = request_irq(irq, ast2600_timer_interrupt,
 386                                   IRQF_TIMER, "FTTMR010-TIMER1",
 387                                   &fttmr010->clkevt);
 388         } else {
 389                 fttmr010->timer_shutdown = fttmr010_timer_shutdown;
 390                 ret = request_irq(irq, fttmr010_timer_interrupt,
 391                                   IRQF_TIMER, "FTTMR010-TIMER1",
 392                                   &fttmr010->clkevt);
 393         }
 394         if (ret) {
 395                 pr_err("FTTMR010-TIMER1 no IRQ\n");
 396                 goto out_unmap;
 397         }
 398
 399         fttmr010->clkevt.name = "FTTMR010-TIMER1";
 400         /* Reasonably fast and accurate clock event */
 401         fttmr010->clkevt.rating = 300;
 402         fttmr010->clkevt.features = CLOCK_EVT_FEAT_PERIODIC |
 403                 CLOCK_EVT_FEAT_ONESHOT;
 404         fttmr010->clkevt.set_next_event = fttmr010_timer_set_next_event;
 405         fttmr010->clkevt.set_state_shutdown = fttmr010->timer_shutdown;
 406         fttmr010->clkevt.set_state_periodic = fttmr010_timer_set_periodic;
 407         fttmr010->clkevt.set_state_oneshot = fttmr010_timer_set_oneshot;
 408         fttmr010->clkevt.tick_resume = fttmr010->timer_shutdown;
 409         fttmr010->clkevt.cpumask = cpumask_of(0);
 410         fttmr010->clkevt.irq = irq;
 411         clockevents_config_and_register(&fttmr010->clkevt,
 412                                         fttmr010->tick_rate,
 413                                         1, 0xffffffff);
 414
 415 #ifdef CONFIG_ARM
 416         /* Also use this timer for delays */
 417         if (fttmr010->is_aspeed)
 418                 fttmr010->delay_timer.read_current_timer =
 419                         fttmr010_read_current_timer_down;
 420         else
 421                 fttmr010->delay_timer.read_current_timer =
 422                         fttmr010_read_current_timer_up;
 423         fttmr010->delay_timer.freq = fttmr010->tick_rate;
 424         register_current_timer_delay(&fttmr010->delay_timer);
 425 #endif
 426
 427         return 0;
 428
 429 out_unmap:
 430         iounmap(fttmr010->base);
 431 out_free:
 432         kfree(fttmr010);
 433 out_disable_clock:
 434         clk_disable_unprepare(clk);
 435
 436         return ret;
 437 }
 438
 439 static __init int ast2600_timer_init(struct device_node *np)
 440 {
 441         return fttmr010_common_init(np, true, true);
 442 }
 443
 444 static __init int aspeed_timer_init(struct device_node *np)
 445 {
 446         return fttmr010_common_init(np, true, false);
 447 }
 448
 449 static __init int fttmr010_timer_init(struct device_node *np)
 450 {
 451         return fttmr010_common_init(np, false, false);
 452 }
 453
 454 TIMER_OF_DECLARE(fttmr010, "faraday,fttmr010", fttmr010_timer_init);
 455 TIMER_OF_DECLARE(gemini, "cortina,gemini-timer", fttmr010_timer_init);
 456 TIMER_OF_DECLARE(moxart, "moxa,moxart-timer", fttmr010_timer_init);
 457 TIMER_OF_DECLARE(ast2400, "aspeed,ast2400-timer", aspeed_timer_init);
 458 TIMER_OF_DECLARE(ast2500, "aspeed,ast2500-timer", aspeed_timer_init);
 459 TIMER_OF_DECLARE(ast2600, "aspeed,ast2600-timer", ast2600_timer_init);