drivers/clocksource/timer-mediatek.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Mediatek SoCs General-Purpose Timer handling.
   4  *
   5  * Copyright (C) 2014 Matthias Brugger
   6  *
   7  * Matthias Brugger <matthias.bgg@gmail.com>
   8  */
   9
  10 #define pr_fmt(fmt)     KBUILD_MODNAME ": " fmt
  11
  12 #include <linux/clockchips.h>
  13 #include <linux/clocksource.h>
  14 #include <linux/interrupt.h>
  15 #include <linux/irqreturn.h>
  16 #include <linux/sched_clock.h>
  17 #include <linux/slab.h>
  18 #include "timer-of.h"
  19
  20 #define TIMER_CLK_EVT           (1)
  21 #define TIMER_CLK_SRC           (2)
  22
  23 #define TIMER_SYNC_TICKS        (3)
  24
  25 /* cpux mcusys wrapper */
  26 #define CPUX_CON_REG            0x0
  27 #define CPUX_IDX_REG            0x4
  28
  29 /* cpux */
  30 #define CPUX_IDX_GLOBAL_CTRL    0x0
  31  #define CPUX_ENABLE            BIT(0)
  32  #define CPUX_CLK_DIV_MASK      GENMASK(10, 8)
  33  #define CPUX_CLK_DIV1          BIT(8)
  34  #define CPUX_CLK_DIV2          BIT(9)
  35  #define CPUX_CLK_DIV4          BIT(10)
  36 #define CPUX_IDX_GLOBAL_IRQ     0x30
  37
  38 /* gpt */
  39 #define GPT_IRQ_EN_REG          0x00
  40 #define GPT_IRQ_ENABLE(val)     BIT((val) - 1)
  41 #define GPT_IRQ_ACK_REG         0x08
  42 #define GPT_IRQ_ACK(val)        BIT((val) - 1)
  43
  44 #define GPT_CTRL_REG(val)       (0x10 * (val))
  45 #define GPT_CTRL_OP(val)        (((val) & 0x3) << 4)
  46 #define GPT_CTRL_OP_ONESHOT     (0)
  47 #define GPT_CTRL_OP_REPEAT      (1)
  48 #define GPT_CTRL_OP_FREERUN     (3)
  49 #define GPT_CTRL_CLEAR          (2)
  50 #define GPT_CTRL_ENABLE         (1)
  51 #define GPT_CTRL_DISABLE        (0)
  52
  53 #define GPT_CLK_REG(val)        (0x04 + (0x10 * (val)))
  54 #define GPT_CLK_SRC(val)        (((val) & 0x1) << 4)
  55 #define GPT_CLK_SRC_SYS13M      (0)
  56 #define GPT_CLK_SRC_RTC32K      (1)
  57 #define GPT_CLK_DIV1            (0x0)
  58 #define GPT_CLK_DIV2            (0x1)
  59
  60 #define GPT_CNT_REG(val)        (0x08 + (0x10 * (val)))
  61 #define GPT_CMP_REG(val)        (0x0C + (0x10 * (val)))
  62
  63 /* system timer */
  64 #define SYST_BASE               (0x40)
  65
  66 #define SYST_CON                (SYST_BASE + 0x0)
  67 #define SYST_VAL                (SYST_BASE + 0x4)
  68
  69 #define SYST_CON_REG(to)        (timer_of_base(to) + SYST_CON)
  70 #define SYST_VAL_REG(to)        (timer_of_base(to) + SYST_VAL)
  71
  72 /*
  73  * SYST_CON_EN: Clock enable. Shall be set to
  74  *   - Start timer countdown.
  75  *   - Allow timeout ticks being updated.
  76  *   - Allow changing interrupt status,like clear irq pending.
  77  *
  78  * SYST_CON_IRQ_EN: Set to enable interrupt.
  79  *
  80  * SYST_CON_IRQ_CLR: Set to clear interrupt.
  81  */
  82 #define SYST_CON_EN              BIT(0)
  83 #define SYST_CON_IRQ_EN          BIT(1)
  84 #define SYST_CON_IRQ_CLR         BIT(4)
  85
  86 static void __iomem *gpt_sched_reg __read_mostly;
  87
  88 static u32 mtk_cpux_readl(u32 reg_idx, struct timer_of *to)
  89 {
  90         writel(reg_idx, timer_of_base(to) + CPUX_IDX_REG);
  91         return readl(timer_of_base(to) + CPUX_CON_REG);
  92 }
  93
  94 static void mtk_cpux_writel(u32 val, u32 reg_idx, struct timer_of *to)
  95 {
  96         writel(reg_idx, timer_of_base(to) + CPUX_IDX_REG);
  97         writel(val, timer_of_base(to) + CPUX_CON_REG);
  98 }
  99
 100 static void mtk_cpux_set_irq(struct timer_of *to, bool enable)
 101 {
 102         const unsigned long *irq_mask = cpumask_bits(cpu_possible_mask);
 103         u32 val;
 104
 105         val = mtk_cpux_readl(CPUX_IDX_GLOBAL_IRQ, to);
 106
 107         if (enable)
 108                 val |= *irq_mask;
 109         else
 110                 val &= ~(*irq_mask);
 111
 112         mtk_cpux_writel(val, CPUX_IDX_GLOBAL_IRQ, to);
 113 }
 114
 115 static int mtk_cpux_clkevt_shutdown(struct clock_event_device *clkevt)
 116 {
 117         /* Clear any irq */
 118         mtk_cpux_set_irq(to_timer_of(clkevt), false);
 119
 120         /*
 121          * Disabling CPUXGPT timer will crash the platform, especially
 122          * if Trusted Firmware is using it (usually, for sleep states),
 123          * so we only mask the IRQ and call it a day.
 124          */
 125         return 0;
 126 }
 127
 128 static int mtk_cpux_clkevt_resume(struct clock_event_device *clkevt)
 129 {
 130         mtk_cpux_set_irq(to_timer_of(clkevt), true);
 131         return 0;
 132 }
 133
 134 static void mtk_syst_ack_irq(struct timer_of *to)
 135 {
 136         /* Clear and disable interrupt */
 137         writel(SYST_CON_EN, SYST_CON_REG(to));
 138         writel(SYST_CON_IRQ_CLR | SYST_CON_EN, SYST_CON_REG(to));
 139 }
 140
 141 static irqreturn_t mtk_syst_handler(int irq, void *dev_id)
 142 {
 143         struct clock_event_device *clkevt = dev_id;
 144         struct timer_of *to = to_timer_of(clkevt);
 145
 146         mtk_syst_ack_irq(to);
 147         clkevt->event_handler(clkevt);
 148
 149         return IRQ_HANDLED;
 150 }
 151
 152 static int mtk_syst_clkevt_next_event(unsigned long ticks,
 153                                       struct clock_event_device *clkevt)
 154 {
 155         struct timer_of *to = to_timer_of(clkevt);
 156
 157         /* Enable clock to allow timeout tick update later */
 158         writel(SYST_CON_EN, SYST_CON_REG(to));
 159
 160         /*
 161          * Write new timeout ticks. Timer shall start countdown
 162          * after timeout ticks are updated.
 163          */
 164         writel(ticks, SYST_VAL_REG(to));
 165
 166         /* Enable interrupt */
 167         writel(SYST_CON_EN | SYST_CON_IRQ_EN, SYST_CON_REG(to));
 168
 169         return 0;
 170 }
 171
 172 static int mtk_syst_clkevt_shutdown(struct clock_event_device *clkevt)
 173 {
 174         /* Clear any irq */
 175         mtk_syst_ack_irq(to_timer_of(clkevt));
 176
 177         /* Disable timer */
 178         writel(0, SYST_CON_REG(to_timer_of(clkevt)));
 179
 180         return 0;
 181 }
 182
 183 static int mtk_syst_clkevt_resume(struct clock_event_device *clkevt)
 184 {
 185         return mtk_syst_clkevt_shutdown(clkevt);
 186 }
 187
 188 static int mtk_syst_clkevt_oneshot(struct clock_event_device *clkevt)
 189 {
 190         return 0;
 191 }
 192
 193 static u64 notrace mtk_gpt_read_sched_clock(void)
 194 {
 195         return readl_relaxed(gpt_sched_reg);
 196 }
 197
 198 static void mtk_gpt_clkevt_time_stop(struct timer_of *to, u8 timer)
 199 {
 200         u32 val;
 201
 202         val = readl(timer_of_base(to) + GPT_CTRL_REG(timer));
 203         writel(val & ~GPT_CTRL_ENABLE, timer_of_base(to) +
 204                GPT_CTRL_REG(timer));
 205 }
 206
 207 static void mtk_gpt_clkevt_time_setup(struct timer_of *to,
 208                                       unsigned long delay, u8 timer)
 209 {
 210         writel(delay, timer_of_base(to) + GPT_CMP_REG(timer));
 211 }
 212
 213 static void mtk_gpt_clkevt_time_start(struct timer_of *to,
 214                                       bool periodic, u8 timer)
 215 {
 216         u32 val;
 217
 218         /* Acknowledge interrupt */
 219         writel(GPT_IRQ_ACK(timer), timer_of_base(to) + GPT_IRQ_ACK_REG);
 220
 221         val = readl(timer_of_base(to) + GPT_CTRL_REG(timer));
 222
 223         /* Clear 2 bit timer operation mode field */
 224         val &= ~GPT_CTRL_OP(0x3);
 225
 226         if (periodic)
 227                 val |= GPT_CTRL_OP(GPT_CTRL_OP_REPEAT);
 228         else
 229                 val |= GPT_CTRL_OP(GPT_CTRL_OP_ONESHOT);
 230
 231         writel(val | GPT_CTRL_ENABLE | GPT_CTRL_CLEAR,
 232                timer_of_base(to) + GPT_CTRL_REG(timer));
 233 }
 234
 235 static int mtk_gpt_clkevt_shutdown(struct clock_event_device *clk)
 236 {
 237         mtk_gpt_clkevt_time_stop(to_timer_of(clk), TIMER_CLK_EVT);
 238
 239         return 0;
 240 }
 241
 242 static int mtk_gpt_clkevt_set_periodic(struct clock_event_device *clk)
 243 {
 244         struct timer_of *to = to_timer_of(clk);
 245
 246         mtk_gpt_clkevt_time_stop(to, TIMER_CLK_EVT);
 247         mtk_gpt_clkevt_time_setup(to, to->of_clk.period, TIMER_CLK_EVT);
 248         mtk_gpt_clkevt_time_start(to, true, TIMER_CLK_EVT);
 249
 250         return 0;
 251 }
 252
 253 static int mtk_gpt_clkevt_next_event(unsigned long event,
 254                                      struct clock_event_device *clk)
 255 {
 256         struct timer_of *to = to_timer_of(clk);
 257
 258         mtk_gpt_clkevt_time_stop(to, TIMER_CLK_EVT);
 259         mtk_gpt_clkevt_time_setup(to, event, TIMER_CLK_EVT);
 260         mtk_gpt_clkevt_time_start(to, false, TIMER_CLK_EVT);
 261
 262         return 0;
 263 }
 264
 265 static irqreturn_t mtk_gpt_interrupt(int irq, void *dev_id)
 266 {
 267         struct clock_event_device *clkevt = (struct clock_event_device *)dev_id;
 268         struct timer_of *to = to_timer_of(clkevt);
 269
 270         /* Acknowledge timer0 irq */
 271         writel(GPT_IRQ_ACK(TIMER_CLK_EVT), timer_of_base(to) + GPT_IRQ_ACK_REG);
 272         clkevt->event_handler(clkevt);
 273
 274         return IRQ_HANDLED;
 275 }
 276
 277 static void
 278 __init mtk_gpt_setup(struct timer_of *to, u8 timer, u8 option)
 279 {
 280         writel(GPT_CTRL_CLEAR | GPT_CTRL_DISABLE,
 281                timer_of_base(to) + GPT_CTRL_REG(timer));
 282
 283         writel(GPT_CLK_SRC(GPT_CLK_SRC_SYS13M) | GPT_CLK_DIV1,
 284                timer_of_base(to) + GPT_CLK_REG(timer));
 285
 286         writel(0x0, timer_of_base(to) + GPT_CMP_REG(timer));
 287
 288         writel(GPT_CTRL_OP(option) | GPT_CTRL_ENABLE,
 289                timer_of_base(to) + GPT_CTRL_REG(timer));
 290 }
 291
 292 static void mtk_gpt_enable_irq(struct timer_of *to, u8 timer)
 293 {
 294         u32 val;
 295
 296         /* Disable all interrupts */
 297         writel(0x0, timer_of_base(to) + GPT_IRQ_EN_REG);
 298
 299         /* Acknowledge all spurious pending interrupts */
 300         writel(0x3f, timer_of_base(to) + GPT_IRQ_ACK_REG);
 301
 302         val = readl(timer_of_base(to) + GPT_IRQ_EN_REG);
 303         writel(val | GPT_IRQ_ENABLE(timer),
 304                timer_of_base(to) + GPT_IRQ_EN_REG);
 305 }
 306
 307 static void mtk_gpt_resume(struct clock_event_device *clk)
 308 {
 309         struct timer_of *to = to_timer_of(clk);
 310
 311         mtk_gpt_enable_irq(to, TIMER_CLK_EVT);
 312 }
 313
 314 static void mtk_gpt_suspend(struct clock_event_device *clk)
 315 {
 316         struct timer_of *to = to_timer_of(clk);
 317
 318         /* Disable all interrupts */
 319         writel(0x0, timer_of_base(to) + GPT_IRQ_EN_REG);
 320
 321         /*
 322          * This is called with interrupts disabled,
 323          * so we need to ack any interrupt that is pending
 324          * or for example ATF will prevent a suspend from completing.
 325          */
 326         writel(0x3f, timer_of_base(to) + GPT_IRQ_ACK_REG);
 327 }
 328
 329 static struct timer_of to = {
 330         .flags = TIMER_OF_IRQ | TIMER_OF_BASE | TIMER_OF_CLOCK,
 331
 332         .clkevt = {
 333                 .name = "mtk-clkevt",
 334                 .rating = 300,
 335                 .cpumask = cpu_possible_mask,
 336         },
 337
 338         .of_irq = {
 339                 .flags = IRQF_TIMER | IRQF_IRQPOLL,
 340         },
 341 };
 342
 343 static int __init mtk_cpux_init(struct device_node *node)
 344 {
 345         static struct timer_of to_cpux;
 346         u32 freq, val;
 347         int ret;
 348
 349         /*
 350          * There are per-cpu interrupts for the CPUX General Purpose Timer
 351          * but since this timer feeds the AArch64 System Timer we can rely
 352          * on the CPU timer PPIs as well, so we don't declare TIMER_OF_IRQ.
 353          */
 354         to_cpux.flags = TIMER_OF_BASE | TIMER_OF_CLOCK;
 355         to_cpux.clkevt.name = "mtk-cpuxgpt";
 356         to_cpux.clkevt.rating = 10;
 357         to_cpux.clkevt.cpumask = cpu_possible_mask;
 358         to_cpux.clkevt.set_state_shutdown = mtk_cpux_clkevt_shutdown;
 359         to_cpux.clkevt.tick_resume = mtk_cpux_clkevt_resume;
 360
 361         /* If this fails, bad things are about to happen... */
 362         ret = timer_of_init(node, &to_cpux);
 363         if (ret) {
 364                 WARN(1, "Cannot start CPUX timers.\n");
 365                 return ret;
 366         }
 367
 368         /*
 369          * Check if we're given a clock with the right frequency for this
 370          * timer, otherwise warn but keep going with the setup anyway, as
 371          * that makes it possible to still boot the kernel, even though
 372          * it may not work correctly (random lockups, etc).
 373          * The reason behind this is that having an early UART may not be
 374          * possible for everyone and this gives a chance to retrieve kmsg
 375          * for eventual debugging even on consumer devices.
 376          */
 377         freq = timer_of_rate(&to_cpux);
 378         if (freq > 13000000)
 379                 WARN(1, "Requested unsupported timer frequency %u\n", freq);
 380
 381         /* Clock input is 26MHz, set DIV2 to achieve 13MHz clock */
 382         val = mtk_cpux_readl(CPUX_IDX_GLOBAL_CTRL, &to_cpux);
 383         val &= ~CPUX_CLK_DIV_MASK;
 384         val |= CPUX_CLK_DIV2;
 385         mtk_cpux_writel(val, CPUX_IDX_GLOBAL_CTRL, &to_cpux);
 386
 387         /* Enable all CPUXGPT timers */
 388         val = mtk_cpux_readl(CPUX_IDX_GLOBAL_CTRL, &to_cpux);
 389         mtk_cpux_writel(val | CPUX_ENABLE, CPUX_IDX_GLOBAL_CTRL, &to_cpux);
 390
 391         clockevents_config_and_register(&to_cpux.clkevt, timer_of_rate(&to_cpux),
 392                                         TIMER_SYNC_TICKS, 0xffffffff);
 393
 394         return 0;
 395 }
 396
 397 static int __init mtk_syst_init(struct device_node *node)
 398 {
 399         int ret;
 400
 401         to.clkevt.features = CLOCK_EVT_FEAT_DYNIRQ | CLOCK_EVT_FEAT_ONESHOT;
 402         to.clkevt.set_state_shutdown = mtk_syst_clkevt_shutdown;
 403         to.clkevt.set_state_oneshot = mtk_syst_clkevt_oneshot;
 404         to.clkevt.tick_resume = mtk_syst_clkevt_resume;
 405         to.clkevt.set_next_event = mtk_syst_clkevt_next_event;
 406         to.of_irq.handler = mtk_syst_handler;
 407
 408         ret = timer_of_init(node, &to);
 409         if (ret)
 410                 return ret;
 411
 412         clockevents_config_and_register(&to.clkevt, timer_of_rate(&to),
 413                                         TIMER_SYNC_TICKS, 0xffffffff);
 414
 415         return 0;
 416 }
 417
 418 static int __init mtk_gpt_init(struct device_node *node)
 419 {
 420         int ret;
 421
 422         to.clkevt.features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT;
 423         to.clkevt.set_state_shutdown = mtk_gpt_clkevt_shutdown;
 424         to.clkevt.set_state_periodic = mtk_gpt_clkevt_set_periodic;
 425         to.clkevt.set_state_oneshot = mtk_gpt_clkevt_shutdown;
 426         to.clkevt.tick_resume = mtk_gpt_clkevt_shutdown;
 427         to.clkevt.set_next_event = mtk_gpt_clkevt_next_event;
 428         to.clkevt.suspend = mtk_gpt_suspend;
 429         to.clkevt.resume = mtk_gpt_resume;
 430         to.of_irq.handler = mtk_gpt_interrupt;
 431
 432         ret = timer_of_init(node, &to);
 433         if (ret)
 434                 return ret;
 435
 436         /* Configure clock source */
 437         mtk_gpt_setup(&to, TIMER_CLK_SRC, GPT_CTRL_OP_FREERUN);
 438         clocksource_mmio_init(timer_of_base(&to) + GPT_CNT_REG(TIMER_CLK_SRC),
 439                               node->name, timer_of_rate(&to), 300, 32,
 440                               clocksource_mmio_readl_up);
 441         gpt_sched_reg = timer_of_base(&to) + GPT_CNT_REG(TIMER_CLK_SRC);
 442         sched_clock_register(mtk_gpt_read_sched_clock, 32, timer_of_rate(&to));
 443
 444         /* Configure clock event */
 445         mtk_gpt_setup(&to, TIMER_CLK_EVT, GPT_CTRL_OP_REPEAT);
 446         clockevents_config_and_register(&to.clkevt, timer_of_rate(&to),
 447                                         TIMER_SYNC_TICKS, 0xffffffff);
 448
 449         mtk_gpt_enable_irq(&to, TIMER_CLK_EVT);
 450
 451         return 0;
 452 }
 453 TIMER_OF_DECLARE(mtk_mt6577, "mediatek,mt6577-timer", mtk_gpt_init);
 454 TIMER_OF_DECLARE(mtk_mt6765, "mediatek,mt6765-timer", mtk_syst_init);
 455 TIMER_OF_DECLARE(mtk_mt6795, "mediatek,mt6795-systimer", mtk_cpux_init);