drivers/clocksource/timer-sun4i.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Allwinner A1X SoCs timer handling.
   4  *
   5  * Copyright (C) 2012 Maxime Ripard
   6  *
   7  * Maxime Ripard <maxime.ripard@free-electrons.com>
   8  *
   9  * Based on code from
  10  * Allwinner Technology Co., Ltd. <www.allwinnertech.com>
  11  * Benn Huang <benn@allwinnertech.com>
  12  */
  13
  14 #include <linux/clk.h>
  15 #include <linux/clockchips.h>
  16 #include <linux/interrupt.h>
  17 #include <linux/irq.h>
  18 #include <linux/irqreturn.h>
  19 #include <linux/sched_clock.h>
  20 #include <linux/of.h>
  21 #include <linux/of_address.h>
  22 #include <linux/of_irq.h>
  23
  24 #include "timer-of.h"
  25
  26 #define TIMER_IRQ_EN_REG        0x00
  27 #define TIMER_IRQ_EN(val)               BIT(val)
  28 #define TIMER_IRQ_ST_REG        0x04
  29 #define TIMER_IRQ_CLEAR(val)            BIT(val)
  30 #define TIMER_CTL_REG(val)      (0x10 * val + 0x10)
  31 #define TIMER_CTL_ENABLE                BIT(0)
  32 #define TIMER_CTL_RELOAD                BIT(1)
  33 #define TIMER_CTL_CLK_SRC(val)          (((val) & 0x3) << 2)
  34 #define TIMER_CTL_CLK_SRC_OSC24M                (1)
  35 #define TIMER_CTL_CLK_PRES(val)         (((val) & 0x7) << 4)
  36 #define TIMER_CTL_ONESHOT               BIT(7)
  37 #define TIMER_INTVAL_REG(val)   (0x10 * (val) + 0x14)
  38 #define TIMER_CNTVAL_REG(val)   (0x10 * (val) + 0x18)
  39
  40 #define TIMER_SYNC_TICKS        3
  41
  42 /*
  43  * When we disable a timer, we need to wait at least for 2 cycles of
  44  * the timer source clock. We will use for that the clocksource timer
  45  * that is already setup and runs at the same frequency than the other
  46  * timers, and we never will be disabled.
  47  */
  48 static void sun4i_clkevt_sync(void __iomem *base)
  49 {
  50         u32 old = readl(base + TIMER_CNTVAL_REG(1));
  51
  52         while ((old - readl(base + TIMER_CNTVAL_REG(1))) < TIMER_SYNC_TICKS)
  53                 cpu_relax();
  54 }
  55
  56 static void sun4i_clkevt_time_stop(void __iomem *base, u8 timer)
  57 {
  58         u32 val = readl(base + TIMER_CTL_REG(timer));
  59         writel(val & ~TIMER_CTL_ENABLE, base + TIMER_CTL_REG(timer));
  60         sun4i_clkevt_sync(base);
  61 }
  62
  63 static void sun4i_clkevt_time_setup(void __iomem *base, u8 timer,
  64                                     unsigned long delay)
  65 {
  66         writel(delay, base + TIMER_INTVAL_REG(timer));
  67 }
  68
  69 static void sun4i_clkevt_time_start(void __iomem *base, u8 timer,
  70                                     bool periodic)
  71 {
  72         u32 val = readl(base + TIMER_CTL_REG(timer));
  73
  74         if (periodic)
  75                 val &= ~TIMER_CTL_ONESHOT;
  76         else
  77                 val |= TIMER_CTL_ONESHOT;
  78
  79         writel(val | TIMER_CTL_ENABLE | TIMER_CTL_RELOAD,
  80                base + TIMER_CTL_REG(timer));
  81 }
  82
  83 static int sun4i_clkevt_shutdown(struct clock_event_device *evt)
  84 {
  85         struct timer_of *to = to_timer_of(evt);
  86
  87         sun4i_clkevt_time_stop(timer_of_base(to), 0);
  88
  89         return 0;
  90 }
  91
  92 static int sun4i_clkevt_set_oneshot(struct clock_event_device *evt)
  93 {
  94         struct timer_of *to = to_timer_of(evt);
  95
  96         sun4i_clkevt_time_stop(timer_of_base(to), 0);
  97         sun4i_clkevt_time_start(timer_of_base(to), 0, false);
  98
  99         return 0;
 100 }
 101
 102 static int sun4i_clkevt_set_periodic(struct clock_event_device *evt)
 103 {
 104         struct timer_of *to = to_timer_of(evt);
 105
 106         sun4i_clkevt_time_stop(timer_of_base(to), 0);
 107         sun4i_clkevt_time_setup(timer_of_base(to), 0, timer_of_period(to));
 108         sun4i_clkevt_time_start(timer_of_base(to), 0, true);
 109
 110         return 0;
 111 }
 112
 113 static int sun4i_clkevt_next_event(unsigned long evt,
 114                                    struct clock_event_device *clkevt)
 115 {
 116         struct timer_of *to = to_timer_of(clkevt);
 117
 118         sun4i_clkevt_time_stop(timer_of_base(to), 0);
 119         sun4i_clkevt_time_setup(timer_of_base(to), 0, evt - TIMER_SYNC_TICKS);
 120         sun4i_clkevt_time_start(timer_of_base(to), 0, false);
 121
 122         return 0;
 123 }
 124
 125 static void sun4i_timer_clear_interrupt(void __iomem *base)
 126 {
 127         writel(TIMER_IRQ_CLEAR(0), base + TIMER_IRQ_ST_REG);
 128 }
 129
 130 static irqreturn_t sun4i_timer_interrupt(int irq, void *dev_id)
 131 {
 132         struct clock_event_device *evt = dev_id;
 133         struct timer_of *to = to_timer_of(evt);
 134
 135         sun4i_timer_clear_interrupt(timer_of_base(to));
 136         evt->event_handler(evt);
 137
 138         return IRQ_HANDLED;
 139 }
 140
 141 static struct timer_of to = {
 142         .flags = TIMER_OF_IRQ | TIMER_OF_CLOCK | TIMER_OF_BASE,
 143
 144         .clkevt = {
 145                 .name = "sun4i_tick",
 146                 .rating = 350,
 147                 .features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT,
 148                 .set_state_shutdown = sun4i_clkevt_shutdown,
 149                 .set_state_periodic = sun4i_clkevt_set_periodic,
 150                 .set_state_oneshot = sun4i_clkevt_set_oneshot,
 151                 .tick_resume = sun4i_clkevt_shutdown,
 152                 .set_next_event = sun4i_clkevt_next_event,
 153                 .cpumask = cpu_possible_mask,
 154         },
 155
 156         .of_irq = {
 157                 .handler = sun4i_timer_interrupt,
 158                 .flags = IRQF_TIMER | IRQF_IRQPOLL,
 159         },
 160 };
 161
 162 static u64 notrace sun4i_timer_sched_read(void)
 163 {
 164         return ~readl(timer_of_base(&to) + TIMER_CNTVAL_REG(1));
 165 }
 166
 167 static int __init sun4i_timer_init(struct device_node *node)
 168 {
 169         int ret;
 170         u32 val;
 171
 172         ret = timer_of_init(node, &to);
 173         if (ret)
 174                 return ret;
 175
 176         writel(~0, timer_of_base(&to) + TIMER_INTVAL_REG(1));
 177         writel(TIMER_CTL_ENABLE | TIMER_CTL_RELOAD |
 178                TIMER_CTL_CLK_SRC(TIMER_CTL_CLK_SRC_OSC24M),
 179                timer_of_base(&to) + TIMER_CTL_REG(1));
 180
 181         /*
 182          * sched_clock_register does not have priorities, and on sun6i and
 183          * later there is a better sched_clock registered by arm_arch_timer.c
 184          */
 185         if (of_machine_is_compatible("allwinner,sun4i-a10") ||
 186             of_machine_is_compatible("allwinner,sun5i-a13") ||
 187             of_machine_is_compatible("allwinner,sun5i-a10s") ||
 188             of_machine_is_compatible("allwinner,suniv-f1c100s"))
 189                 sched_clock_register(sun4i_timer_sched_read, 32,
 190                                      timer_of_rate(&to));
 191
 192         ret = clocksource_mmio_init(timer_of_base(&to) + TIMER_CNTVAL_REG(1),
 193                                     node->name, timer_of_rate(&to), 350, 32,
 194                                     clocksource_mmio_readl_down);
 195         if (ret) {
 196                 pr_err("Failed to register clocksource\n");
 197                 return ret;
 198         }
 199
 200         writel(TIMER_CTL_CLK_SRC(TIMER_CTL_CLK_SRC_OSC24M),
 201                timer_of_base(&to) + TIMER_CTL_REG(0));
 202
 203         /* Make sure timer is stopped before playing with interrupts */
 204         sun4i_clkevt_time_stop(timer_of_base(&to), 0);
 205
 206         /* clear timer0 interrupt */
 207         sun4i_timer_clear_interrupt(timer_of_base(&to));
 208
 209         clockevents_config_and_register(&to.clkevt, timer_of_rate(&to),
 210                                         TIMER_SYNC_TICKS, 0xffffffff);
 211
 212         /* Enable timer0 interrupt */
 213         val = readl(timer_of_base(&to) + TIMER_IRQ_EN_REG);
 214         writel(val | TIMER_IRQ_EN(0), timer_of_base(&to) + TIMER_IRQ_EN_REG);
 215
 216         return ret;
 217 }
 218 TIMER_OF_DECLARE(sun4i, "allwinner,sun4i-a10-timer",
 219                        sun4i_timer_init);
 220 TIMER_OF_DECLARE(sun8i_a23, "allwinner,sun8i-a23-timer",
 221                  sun4i_timer_init);
 222 TIMER_OF_DECLARE(sun8i_v3s, "allwinner,sun8i-v3s-timer",
 223                  sun4i_timer_init);
 224 TIMER_OF_DECLARE(suniv, "allwinner,suniv-f1c100s-timer",
 225                        sun4i_timer_init);