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