drivers/clocksource/timer-sun5i.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Allwinner SoCs hstimer driver.
   4  *
   5  * Copyright (C) 2013 Maxime Ripard
   6  *
   7  * Maxime Ripard <maxime.ripard@free-electrons.com>
   8  */
   9
  10 #include <linux/clk.h>
  11 #include <linux/clockchips.h>
  12 #include <linux/clocksource.h>
  13 #include <linux/delay.h>
  14 #include <linux/interrupt.h>
  15 #include <linux/irq.h>
  16 #include <linux/irqreturn.h>
  17 #include <linux/reset.h>
  18 #include <linux/slab.h>
  19 #include <linux/platform_device.h>
  20
  21 #define TIMER_IRQ_EN_REG                0x00
  22 #define TIMER_IRQ_EN(val)                       BIT(val)
  23 #define TIMER_IRQ_ST_REG                0x04
  24 #define TIMER_CTL_REG(val)              (0x20 * (val) + 0x10)
  25 #define TIMER_CTL_ENABLE                        BIT(0)
  26 #define TIMER_CTL_RELOAD                        BIT(1)
  27 #define TIMER_CTL_CLK_PRES(val)                 (((val) & 0x7) << 4)
  28 #define TIMER_CTL_ONESHOT                       BIT(7)
  29 #define TIMER_INTVAL_LO_REG(val)        (0x20 * (val) + 0x14)
  30 #define TIMER_INTVAL_HI_REG(val)        (0x20 * (val) + 0x18)
  31 #define TIMER_CNTVAL_LO_REG(val)        (0x20 * (val) + 0x1c)
  32 #define TIMER_CNTVAL_HI_REG(val)        (0x20 * (val) + 0x20)
  33
  34 #define TIMER_SYNC_TICKS        3
  35
  36 struct sun5i_timer {
  37         void __iomem            *base;
  38         struct clk              *clk;
  39         struct notifier_block   clk_rate_cb;
  40         u32                     ticks_per_jiffy;
  41         struct clocksource      clksrc;
  42         struct clock_event_device       clkevt;
  43 };
  44
  45 #define nb_to_sun5i_timer(x) \
  46         container_of(x, struct sun5i_timer, clk_rate_cb)
  47 #define clksrc_to_sun5i_timer(x) \
  48         container_of(x, struct sun5i_timer, clksrc)
  49 #define clkevt_to_sun5i_timer(x) \
  50         container_of(x, struct sun5i_timer, clkevt)
  51
  52 /*
  53  * When we disable a timer, we need to wait at least for 2 cycles of
  54  * the timer source clock. We will use for that the clocksource timer
  55  * that is already setup and runs at the same frequency than the other
  56  * timers, and we never will be disabled.
  57  */
  58 static void sun5i_clkevt_sync(struct sun5i_timer *ce)
  59 {
  60         u32 old = readl(ce->base + TIMER_CNTVAL_LO_REG(1));
  61
  62         while ((old - readl(ce->base + TIMER_CNTVAL_LO_REG(1))) < TIMER_SYNC_TICKS)
  63                 cpu_relax();
  64 }
  65
  66 static void sun5i_clkevt_time_stop(struct sun5i_timer *ce, u8 timer)
  67 {
  68         u32 val = readl(ce->base + TIMER_CTL_REG(timer));
  69         writel(val & ~TIMER_CTL_ENABLE, ce->base + TIMER_CTL_REG(timer));
  70
  71         sun5i_clkevt_sync(ce);
  72 }
  73
  74 static void sun5i_clkevt_time_setup(struct sun5i_timer *ce, u8 timer, u32 delay)
  75 {
  76         writel(delay, ce->base + TIMER_INTVAL_LO_REG(timer));
  77 }
  78
  79 static void sun5i_clkevt_time_start(struct sun5i_timer *ce, u8 timer, bool periodic)
  80 {
  81         u32 val = readl(ce->base + TIMER_CTL_REG(timer));
  82
  83         if (periodic)
  84                 val &= ~TIMER_CTL_ONESHOT;
  85         else
  86                 val |= TIMER_CTL_ONESHOT;
  87
  88         writel(val | TIMER_CTL_ENABLE | TIMER_CTL_RELOAD,
  89                ce->base + TIMER_CTL_REG(timer));
  90 }
  91
  92 static int sun5i_clkevt_shutdown(struct clock_event_device *clkevt)
  93 {
  94         struct sun5i_timer *ce = clkevt_to_sun5i_timer(clkevt);
  95
  96         sun5i_clkevt_time_stop(ce, 0);
  97         return 0;
  98 }
  99
 100 static int sun5i_clkevt_set_oneshot(struct clock_event_device *clkevt)
 101 {
 102         struct sun5i_timer *ce = clkevt_to_sun5i_timer(clkevt);
 103
 104         sun5i_clkevt_time_stop(ce, 0);
 105         sun5i_clkevt_time_start(ce, 0, false);
 106         return 0;
 107 }
 108
 109 static int sun5i_clkevt_set_periodic(struct clock_event_device *clkevt)
 110 {
 111         struct sun5i_timer *ce = clkevt_to_sun5i_timer(clkevt);
 112
 113         sun5i_clkevt_time_stop(ce, 0);
 114         sun5i_clkevt_time_setup(ce, 0, ce->ticks_per_jiffy);
 115         sun5i_clkevt_time_start(ce, 0, true);
 116         return 0;
 117 }
 118
 119 static int sun5i_clkevt_next_event(unsigned long evt,
 120                                    struct clock_event_device *clkevt)
 121 {
 122         struct sun5i_timer *ce = clkevt_to_sun5i_timer(clkevt);
 123
 124         sun5i_clkevt_time_stop(ce, 0);
 125         sun5i_clkevt_time_setup(ce, 0, evt - TIMER_SYNC_TICKS);
 126         sun5i_clkevt_time_start(ce, 0, false);
 127
 128         return 0;
 129 }
 130
 131 static irqreturn_t sun5i_timer_interrupt(int irq, void *dev_id)
 132 {
 133         struct sun5i_timer *ce = dev_id;
 134
 135         writel(0x1, ce->base + TIMER_IRQ_ST_REG);
 136         ce->clkevt.event_handler(&ce->clkevt);
 137
 138         return IRQ_HANDLED;
 139 }
 140
 141 static u64 sun5i_clksrc_read(struct clocksource *clksrc)
 142 {
 143         struct sun5i_timer *cs = clksrc_to_sun5i_timer(clksrc);
 144
 145         return ~readl(cs->base + TIMER_CNTVAL_LO_REG(1));
 146 }
 147
 148 static int sun5i_rate_cb(struct notifier_block *nb,
 149                          unsigned long event, void *data)
 150 {
 151         struct clk_notifier_data *ndata = data;
 152         struct sun5i_timer *cs = nb_to_sun5i_timer(nb);
 153
 154         switch (event) {
 155         case PRE_RATE_CHANGE:
 156                 clocksource_unregister(&cs->clksrc);
 157                 break;
 158
 159         case POST_RATE_CHANGE:
 160                 clocksource_register_hz(&cs->clksrc, ndata->new_rate);
 161                 clockevents_update_freq(&cs->clkevt, ndata->new_rate);
 162                 cs->ticks_per_jiffy = DIV_ROUND_UP(ndata->new_rate, HZ);
 163                 break;
 164
 165         default:
 166                 break;
 167         }
 168
 169         return NOTIFY_DONE;
 170 }
 171
 172 static int sun5i_setup_clocksource(struct platform_device *pdev,
 173                                    unsigned long rate)
 174 {
 175         struct sun5i_timer *cs = platform_get_drvdata(pdev);
 176         void __iomem *base = cs->base;
 177         int ret;
 178
 179         writel(~0, base + TIMER_INTVAL_LO_REG(1));
 180         writel(TIMER_CTL_ENABLE | TIMER_CTL_RELOAD,
 181                base + TIMER_CTL_REG(1));
 182
 183         cs->clksrc.name = pdev->dev.of_node->name;
 184         cs->clksrc.rating = 340;
 185         cs->clksrc.read = sun5i_clksrc_read;
 186         cs->clksrc.mask = CLOCKSOURCE_MASK(32);
 187         cs->clksrc.flags = CLOCK_SOURCE_IS_CONTINUOUS;
 188
 189         ret = clocksource_register_hz(&cs->clksrc, rate);
 190         if (ret) {
 191                 dev_err(&pdev->dev, "Couldn't register clock source.\n");
 192                 return ret;
 193         }
 194
 195         return 0;
 196 }
 197
 198 static int sun5i_setup_clockevent(struct platform_device *pdev,
 199                                   unsigned long rate, int irq)
 200 {
 201         struct device *dev = &pdev->dev;
 202         struct sun5i_timer *ce = platform_get_drvdata(pdev);
 203         void __iomem *base = ce->base;
 204         int ret;
 205         u32 val;
 206
 207         ce->clkevt.name = dev->of_node->name;
 208         ce->clkevt.features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT;
 209         ce->clkevt.set_next_event = sun5i_clkevt_next_event;
 210         ce->clkevt.set_state_shutdown = sun5i_clkevt_shutdown;
 211         ce->clkevt.set_state_periodic = sun5i_clkevt_set_periodic;
 212         ce->clkevt.set_state_oneshot = sun5i_clkevt_set_oneshot;
 213         ce->clkevt.tick_resume = sun5i_clkevt_shutdown;
 214         ce->clkevt.rating = 340;
 215         ce->clkevt.irq = irq;
 216         ce->clkevt.cpumask = cpu_possible_mask;
 217
 218         /* Enable timer0 interrupt */
 219         val = readl(base + TIMER_IRQ_EN_REG);
 220         writel(val | TIMER_IRQ_EN(0), base + TIMER_IRQ_EN_REG);
 221
 222         clockevents_config_and_register(&ce->clkevt, rate,
 223                                         TIMER_SYNC_TICKS, 0xffffffff);
 224
 225         ret = devm_request_irq(dev, irq, sun5i_timer_interrupt,
 226                                IRQF_TIMER | IRQF_IRQPOLL,
 227                                "sun5i_timer0", ce);
 228         if (ret) {
 229                 dev_err(dev, "Unable to register interrupt\n");
 230                 return ret;
 231         }
 232
 233         return 0;
 234 }
 235
 236 static int sun5i_timer_probe(struct platform_device *pdev)
 237 {
 238         struct device *dev = &pdev->dev;
 239         struct sun5i_timer *st;
 240         struct reset_control *rstc;
 241         void __iomem *timer_base;
 242         struct clk *clk;
 243         unsigned long rate;
 244         int irq, ret;
 245
 246         st = devm_kzalloc(dev, sizeof(*st), GFP_KERNEL);
 247         if (!st)
 248                 return -ENOMEM;
 249
 250         platform_set_drvdata(pdev, st);
 251
 252         timer_base = devm_platform_ioremap_resource(pdev, 0);
 253         if (IS_ERR(timer_base)) {
 254                 dev_err(dev, "Can't map registers\n");
 255                 return PTR_ERR(timer_base);
 256         }
 257
 258         irq = platform_get_irq(pdev, 0);
 259         if (irq < 0)
 260                 return irq;
 261
 262         clk = devm_clk_get_enabled(dev, NULL);
 263         if (IS_ERR(clk)) {
 264                 dev_err(dev, "Can't get timer clock\n");
 265                 return PTR_ERR(clk);
 266         }
 267
 268         rate = clk_get_rate(clk);
 269         if (!rate) {
 270                 dev_err(dev, "Couldn't get parent clock rate\n");
 271                 return -EINVAL;
 272         }
 273
 274         st->base = timer_base;
 275         st->ticks_per_jiffy = DIV_ROUND_UP(rate, HZ);
 276         st->clk = clk;
 277         st->clk_rate_cb.notifier_call = sun5i_rate_cb;
 278         st->clk_rate_cb.next = NULL;
 279
 280         ret = devm_clk_notifier_register(dev, clk, &st->clk_rate_cb);
 281         if (ret) {
 282                 dev_err(dev, "Unable to register clock notifier.\n");
 283                 return ret;
 284         }
 285
 286         rstc = devm_reset_control_get_optional_exclusive(dev, NULL);
 287         if (rstc)
 288                 reset_control_deassert(rstc);
 289
 290         ret = sun5i_setup_clocksource(pdev, rate);
 291         if (ret)
 292                 return ret;
 293
 294         ret = sun5i_setup_clockevent(pdev, rate, irq);
 295         if (ret)
 296                 goto err_unreg_clocksource;
 297
 298         return 0;
 299
 300 err_unreg_clocksource:
 301         clocksource_unregister(&st->clksrc);
 302         return ret;
 303 }
 304
 305 static void sun5i_timer_remove(struct platform_device *pdev)
 306 {
 307         struct sun5i_timer *st = platform_get_drvdata(pdev);
 308
 309         clocksource_unregister(&st->clksrc);
 310 }
 311
 312 static const struct of_device_id sun5i_timer_of_match[] = {
 313         { .compatible = "allwinner,sun5i-a13-hstimer" },
 314         { .compatible = "allwinner,sun7i-a20-hstimer" },
 315         {},
 316 };
 317 MODULE_DEVICE_TABLE(of, sun5i_timer_of_match);
 318
 319 static struct platform_driver sun5i_timer_driver = {
 320         .probe          = sun5i_timer_probe,
 321         .remove         = sun5i_timer_remove,
 322         .driver = {
 323                 .name   = "sun5i-timer",
 324                 .of_match_table = sun5i_timer_of_match,
 325                 .suppress_bind_attrs = true,
 326         },
 327 };
 328 module_platform_driver(sun5i_timer_driver);