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 for the timers
  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 #define TIMER_INTR_STATE        (0x34)
  40 #define TIMER_INTR_MASK         (0x38)
  41
  42 #define TIMER_1_CR_ENABLE       BIT(0)
  43 #define TIMER_1_CR_CLOCK        BIT(1)
  44 #define TIMER_1_CR_INT          BIT(2)
  45 #define TIMER_2_CR_ENABLE       BIT(3)
  46 #define TIMER_2_CR_CLOCK        BIT(4)
  47 #define TIMER_2_CR_INT          BIT(5)
  48 #define TIMER_3_CR_ENABLE       BIT(6)
  49 #define TIMER_3_CR_CLOCK        BIT(7)
  50 #define TIMER_3_CR_INT          BIT(8)
  51 #define TIMER_1_CR_UPDOWN       BIT(9)
  52 #define TIMER_2_CR_UPDOWN       BIT(10)
  53 #define TIMER_3_CR_UPDOWN       BIT(11)
  54
  55 /*
  56  * The Aspeed AST2400 moves bits around in the control register
  57  * and lacks bits for setting the timer to count upwards.
  58  */
  59 #define TIMER_1_CR_ASPEED_ENABLE        BIT(0)
  60 #define TIMER_1_CR_ASPEED_CLOCK         BIT(1)
  61 #define TIMER_1_CR_ASPEED_INT           BIT(2)
  62 #define TIMER_2_CR_ASPEED_ENABLE        BIT(4)
  63 #define TIMER_2_CR_ASPEED_CLOCK         BIT(5)
  64 #define TIMER_2_CR_ASPEED_INT           BIT(6)
  65 #define TIMER_3_CR_ASPEED_ENABLE        BIT(8)
  66 #define TIMER_3_CR_ASPEED_CLOCK         BIT(9)
  67 #define TIMER_3_CR_ASPEED_INT           BIT(10)
  68
  69 #define TIMER_1_INT_MATCH1      BIT(0)
  70 #define TIMER_1_INT_MATCH2      BIT(1)
  71 #define TIMER_1_INT_OVERFLOW    BIT(2)
  72 #define TIMER_2_INT_MATCH1      BIT(3)
  73 #define TIMER_2_INT_MATCH2      BIT(4)
  74 #define TIMER_2_INT_OVERFLOW    BIT(5)
  75 #define TIMER_3_INT_MATCH1      BIT(6)
  76 #define TIMER_3_INT_MATCH2      BIT(7)
  77 #define TIMER_3_INT_OVERFLOW    BIT(8)
  78 #define TIMER_INT_ALL_MASK      0x1ff
  79
  80 struct fttmr010 {
  81         void __iomem *base;
  82         unsigned int tick_rate;
  83         bool count_down;
  84         u32 t1_enable_val;
  85         struct clock_event_device clkevt;
  86 #ifdef CONFIG_ARM
  87         struct delay_timer delay_timer;
  88 #endif
  89 };
  90
  91 /*
  92  * A local singleton used by sched_clock and delay timer reads, which are
  93  * fast and stateless
  94  */
  95 static struct fttmr010 *local_fttmr;
  96
  97 static inline struct fttmr010 *to_fttmr010(struct clock_event_device *evt)
  98 {
  99         return container_of(evt, struct fttmr010, clkevt);
 100 }
 101
 102 static unsigned long fttmr010_read_current_timer_up(void)
 103 {
 104         return readl(local_fttmr->base + TIMER2_COUNT);
 105 }
 106
 107 static unsigned long fttmr010_read_current_timer_down(void)
 108 {
 109         return ~readl(local_fttmr->base + TIMER2_COUNT);
 110 }
 111
 112 static u64 notrace fttmr010_read_sched_clock_up(void)
 113 {
 114         return fttmr010_read_current_timer_up();
 115 }
 116
 117 static u64 notrace fttmr010_read_sched_clock_down(void)
 118 {
 119         return fttmr010_read_current_timer_down();
 120 }
 121
 122 static int fttmr010_timer_set_next_event(unsigned long cycles,
 123                                        struct clock_event_device *evt)
 124 {
 125         struct fttmr010 *fttmr010 = to_fttmr010(evt);
 126         u32 cr;
 127
 128         /* Stop */
 129         cr = readl(fttmr010->base + TIMER_CR);
 130         cr &= ~fttmr010->t1_enable_val;
 131         writel(cr, fttmr010->base + TIMER_CR);
 132
 133         /* Setup the match register forward/backward in time */
 134         cr = readl(fttmr010->base + TIMER1_COUNT);
 135         if (fttmr010->count_down)
 136                 cr -= cycles;
 137         else
 138                 cr += cycles;
 139         writel(cr, fttmr010->base + TIMER1_MATCH1);
 140
 141         /* Start */
 142         cr = readl(fttmr010->base + TIMER_CR);
 143         cr |= fttmr010->t1_enable_val;
 144         writel(cr, fttmr010->base + TIMER_CR);
 145
 146         return 0;
 147 }
 148
 149 static int fttmr010_timer_shutdown(struct clock_event_device *evt)
 150 {
 151         struct fttmr010 *fttmr010 = to_fttmr010(evt);
 152         u32 cr;
 153
 154         /* Stop */
 155         cr = readl(fttmr010->base + TIMER_CR);
 156         cr &= ~fttmr010->t1_enable_val;
 157         writel(cr, fttmr010->base + TIMER_CR);
 158
 159         return 0;
 160 }
 161
 162 static int fttmr010_timer_set_oneshot(struct clock_event_device *evt)
 163 {
 164         struct fttmr010 *fttmr010 = to_fttmr010(evt);
 165         u32 cr;
 166
 167         /* Stop */
 168         cr = readl(fttmr010->base + TIMER_CR);
 169         cr &= ~fttmr010->t1_enable_val;
 170         writel(cr, fttmr010->base + TIMER_CR);
 171
 172         /* Setup counter start from 0 or ~0 */
 173         writel(0, fttmr010->base + TIMER1_COUNT);
 174         if (fttmr010->count_down)
 175                 writel(~0, fttmr010->base + TIMER1_LOAD);
 176         else
 177                 writel(0, fttmr010->base + TIMER1_LOAD);
 178
 179         /* Enable interrupt */
 180         cr = readl(fttmr010->base + TIMER_INTR_MASK);
 181         cr &= ~(TIMER_1_INT_OVERFLOW | TIMER_1_INT_MATCH2);
 182         cr |= TIMER_1_INT_MATCH1;
 183         writel(cr, fttmr010->base + TIMER_INTR_MASK);
 184
 185         return 0;
 186 }
 187
 188 static int fttmr010_timer_set_periodic(struct clock_event_device *evt)
 189 {
 190         struct fttmr010 *fttmr010 = to_fttmr010(evt);
 191         u32 period = DIV_ROUND_CLOSEST(fttmr010->tick_rate, HZ);
 192         u32 cr;
 193
 194         /* Stop */
 195         cr = readl(fttmr010->base + TIMER_CR);
 196         cr &= ~fttmr010->t1_enable_val;
 197         writel(cr, fttmr010->base + TIMER_CR);
 198
 199         /* Setup timer to fire at 1/HZ intervals. */
 200         if (fttmr010->count_down) {
 201                 writel(period, fttmr010->base + TIMER1_LOAD);
 202                 writel(0, fttmr010->base + TIMER1_MATCH1);
 203         } else {
 204                 cr = 0xffffffff - (period - 1);
 205                 writel(cr, fttmr010->base + TIMER1_COUNT);
 206                 writel(cr, fttmr010->base + TIMER1_LOAD);
 207
 208                 /* Enable interrupt on overflow */
 209                 cr = readl(fttmr010->base + TIMER_INTR_MASK);
 210                 cr &= ~(TIMER_1_INT_MATCH1 | TIMER_1_INT_MATCH2);
 211                 cr |= TIMER_1_INT_OVERFLOW;
 212                 writel(cr, fttmr010->base + TIMER_INTR_MASK);
 213         }
 214
 215         /* Start the timer */
 216         cr = readl(fttmr010->base + TIMER_CR);
 217         cr |= fttmr010->t1_enable_val;
 218         writel(cr, fttmr010->base + TIMER_CR);
 219
 220         return 0;
 221 }
 222
 223 /*
 224  * IRQ handler for the timer
 225  */
 226 static irqreturn_t fttmr010_timer_interrupt(int irq, void *dev_id)
 227 {
 228         struct clock_event_device *evt = dev_id;
 229
 230         evt->event_handler(evt);
 231         return IRQ_HANDLED;
 232 }
 233
 234 static int __init fttmr010_common_init(struct device_node *np, bool is_aspeed)
 235 {
 236         struct fttmr010 *fttmr010;
 237         int irq;
 238         struct clk *clk;
 239         int ret;
 240         u32 val;
 241
 242         /*
 243          * These implementations require a clock reference.
 244          * FIXME: we currently only support clocking using PCLK
 245          * and using EXTCLK is not supported in the driver.
 246          */
 247         clk = of_clk_get_by_name(np, "PCLK");
 248         if (IS_ERR(clk)) {
 249                 pr_err("could not get PCLK\n");
 250                 return PTR_ERR(clk);
 251         }
 252         ret = clk_prepare_enable(clk);
 253         if (ret) {
 254                 pr_err("failed to enable PCLK\n");
 255                 return ret;
 256         }
 257
 258         fttmr010 = kzalloc(sizeof(*fttmr010), GFP_KERNEL);
 259         if (!fttmr010) {
 260                 ret = -ENOMEM;
 261                 goto out_disable_clock;
 262         }
 263         fttmr010->tick_rate = clk_get_rate(clk);
 264
 265         fttmr010->base = of_iomap(np, 0);
 266         if (!fttmr010->base) {
 267                 pr_err("Can't remap registers");
 268                 ret = -ENXIO;
 269                 goto out_free;
 270         }
 271         /* IRQ for timer 1 */
 272         irq = irq_of_parse_and_map(np, 0);
 273         if (irq <= 0) {
 274                 pr_err("Can't parse IRQ");
 275                 ret = -EINVAL;
 276                 goto out_unmap;
 277         }
 278
 279         /*
 280          * The Aspeed AST2400 moves bits around in the control register,
 281          * otherwise it works the same.
 282          */
 283         if (is_aspeed) {
 284                 fttmr010->t1_enable_val = TIMER_1_CR_ASPEED_ENABLE |
 285                         TIMER_1_CR_ASPEED_INT;
 286                 /* Downward not available */
 287                 fttmr010->count_down = true;
 288         } else {
 289                 fttmr010->t1_enable_val = TIMER_1_CR_ENABLE | TIMER_1_CR_INT;
 290         }
 291
 292         /*
 293          * Reset the interrupt mask and status
 294          */
 295         writel(TIMER_INT_ALL_MASK, fttmr010->base + TIMER_INTR_MASK);
 296         writel(0, fttmr010->base + TIMER_INTR_STATE);
 297
 298         /*
 299          * Enable timer 1 count up, timer 2 count up, except on Aspeed,
 300          * where everything just counts down.
 301          */
 302         if (is_aspeed)
 303                 val = TIMER_2_CR_ASPEED_ENABLE;
 304         else {
 305                 val = TIMER_2_CR_ENABLE;
 306                 if (!fttmr010->count_down)
 307                         val |= TIMER_1_CR_UPDOWN | TIMER_2_CR_UPDOWN;
 308         }
 309         writel(val, fttmr010->base + TIMER_CR);
 310
 311         /*
 312          * Setup free-running clocksource timer (interrupts
 313          * disabled.)
 314          */
 315         local_fttmr = fttmr010;
 316         writel(0, fttmr010->base + TIMER2_COUNT);
 317         writel(0, fttmr010->base + TIMER2_MATCH1);
 318         writel(0, fttmr010->base + TIMER2_MATCH2);
 319
 320         if (fttmr010->count_down) {
 321                 writel(~0, fttmr010->base + TIMER2_LOAD);
 322                 clocksource_mmio_init(fttmr010->base + TIMER2_COUNT,
 323                                       "FTTMR010-TIMER2",
 324                                       fttmr010->tick_rate,
 325                                       300, 32, clocksource_mmio_readl_down);
 326                 sched_clock_register(fttmr010_read_sched_clock_down, 32,
 327                                      fttmr010->tick_rate);
 328         } else {
 329                 writel(0, fttmr010->base + TIMER2_LOAD);
 330                 clocksource_mmio_init(fttmr010->base + TIMER2_COUNT,
 331                                       "FTTMR010-TIMER2",
 332                                       fttmr010->tick_rate,
 333                                       300, 32, clocksource_mmio_readl_up);
 334                 sched_clock_register(fttmr010_read_sched_clock_up, 32,
 335                                      fttmr010->tick_rate);
 336         }
 337
 338         /*
 339          * Setup clockevent timer (interrupt-driven) on timer 1.
 340          */
 341         writel(0, fttmr010->base + TIMER1_COUNT);
 342         writel(0, fttmr010->base + TIMER1_LOAD);
 343         writel(0, fttmr010->base + TIMER1_MATCH1);
 344         writel(0, fttmr010->base + TIMER1_MATCH2);
 345         ret = request_irq(irq, fttmr010_timer_interrupt, IRQF_TIMER,
 346                           "FTTMR010-TIMER1", &fttmr010->clkevt);
 347         if (ret) {
 348                 pr_err("FTTMR010-TIMER1 no IRQ\n");
 349                 goto out_unmap;
 350         }
 351
 352         fttmr010->clkevt.name = "FTTMR010-TIMER1";
 353         /* Reasonably fast and accurate clock event */
 354         fttmr010->clkevt.rating = 300;
 355         fttmr010->clkevt.features = CLOCK_EVT_FEAT_PERIODIC |
 356                 CLOCK_EVT_FEAT_ONESHOT;
 357         fttmr010->clkevt.set_next_event = fttmr010_timer_set_next_event;
 358         fttmr010->clkevt.set_state_shutdown = fttmr010_timer_shutdown;
 359         fttmr010->clkevt.set_state_periodic = fttmr010_timer_set_periodic;
 360         fttmr010->clkevt.set_state_oneshot = fttmr010_timer_set_oneshot;
 361         fttmr010->clkevt.tick_resume = fttmr010_timer_shutdown;
 362         fttmr010->clkevt.cpumask = cpumask_of(0);
 363         fttmr010->clkevt.irq = irq;
 364         clockevents_config_and_register(&fttmr010->clkevt,
 365                                         fttmr010->tick_rate,
 366                                         1, 0xffffffff);
 367
 368 #ifdef CONFIG_ARM
 369         /* Also use this timer for delays */
 370         if (fttmr010->count_down)
 371                 fttmr010->delay_timer.read_current_timer =
 372                         fttmr010_read_current_timer_down;
 373         else
 374                 fttmr010->delay_timer.read_current_timer =
 375                         fttmr010_read_current_timer_up;
 376         fttmr010->delay_timer.freq = fttmr010->tick_rate;
 377         register_current_timer_delay(&fttmr010->delay_timer);
 378 #endif
 379
 380         return 0;
 381
 382 out_unmap:
 383         iounmap(fttmr010->base);
 384 out_free:
 385         kfree(fttmr010);
 386 out_disable_clock:
 387         clk_disable_unprepare(clk);
 388
 389         return ret;
 390 }
 391
 392 static __init int aspeed_timer_init(struct device_node *np)
 393 {
 394         return fttmr010_common_init(np, true);
 395 }
 396
 397 static __init int fttmr010_timer_init(struct device_node *np)
 398 {
 399         return fttmr010_common_init(np, false);
 400 }
 401
 402 TIMER_OF_DECLARE(fttmr010, "faraday,fttmr010", fttmr010_timer_init);
 403 TIMER_OF_DECLARE(gemini, "cortina,gemini-timer", fttmr010_timer_init);
 404 TIMER_OF_DECLARE(moxart, "moxa,moxart-timer", fttmr010_timer_init);
 405 TIMER_OF_DECLARE(ast2400, "aspeed,ast2400-timer", aspeed_timer_init);
 406 TIMER_OF_DECLARE(ast2500, "aspeed,ast2500-timer", aspeed_timer_init);