drivers/clocksource/timer-owl.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Actions Semi Owl timer
   4  *
   5  * Copyright 2012 Actions Semi Inc.
   6  * Author: Actions Semi, Inc.
   7  *
   8  * Copyright (c) 2017 SUSE Linux GmbH
   9  * Author: Andreas Färber
  10  */
  11
  12 #include <linux/clk.h>
  13 #include <linux/clockchips.h>
  14 #include <linux/interrupt.h>
  15 #include <linux/irq.h>
  16 #include <linux/irqreturn.h>
  17 #include <linux/sched_clock.h>
  18 #include <linux/of.h>
  19 #include <linux/of_address.h>
  20 #include <linux/of_irq.h>
  21
  22 #define OWL_Tx_CTL              0x0
  23 #define OWL_Tx_CMP              0x4
  24 #define OWL_Tx_VAL              0x8
  25
  26 #define OWL_Tx_CTL_PD           BIT(0)
  27 #define OWL_Tx_CTL_INTEN        BIT(1)
  28 #define OWL_Tx_CTL_EN           BIT(2)
  29
  30 static void __iomem *owl_timer_base;
  31 static void __iomem *owl_clksrc_base;
  32 static void __iomem *owl_clkevt_base;
  33
  34 static inline void owl_timer_reset(void __iomem *base)
  35 {
  36         writel(0, base + OWL_Tx_CTL);
  37         writel(0, base + OWL_Tx_VAL);
  38         writel(0, base + OWL_Tx_CMP);
  39 }
  40
  41 static inline void owl_timer_set_enabled(void __iomem *base, bool enabled)
  42 {
  43         u32 ctl = readl(base + OWL_Tx_CTL);
  44
  45         /* PD bit is cleared when set */
  46         ctl &= ~OWL_Tx_CTL_PD;
  47
  48         if (enabled)
  49                 ctl |= OWL_Tx_CTL_EN;
  50         else
  51                 ctl &= ~OWL_Tx_CTL_EN;
  52
  53         writel(ctl, base + OWL_Tx_CTL);
  54 }
  55
  56 static u64 notrace owl_timer_sched_read(void)
  57 {
  58         return (u64)readl(owl_clksrc_base + OWL_Tx_VAL);
  59 }
  60
  61 static int owl_timer_set_state_shutdown(struct clock_event_device *evt)
  62 {
  63         owl_timer_set_enabled(owl_clkevt_base, false);
  64
  65         return 0;
  66 }
  67
  68 static int owl_timer_set_state_oneshot(struct clock_event_device *evt)
  69 {
  70         owl_timer_reset(owl_clkevt_base);
  71
  72         return 0;
  73 }
  74
  75 static int owl_timer_tick_resume(struct clock_event_device *evt)
  76 {
  77         return 0;
  78 }
  79
  80 static int owl_timer_set_next_event(unsigned long evt,
  81                                     struct clock_event_device *ev)
  82 {
  83         void __iomem *base = owl_clkevt_base;
  84
  85         owl_timer_set_enabled(base, false);
  86         writel(OWL_Tx_CTL_INTEN, base + OWL_Tx_CTL);
  87         writel(0, base + OWL_Tx_VAL);
  88         writel(evt, base + OWL_Tx_CMP);
  89         owl_timer_set_enabled(base, true);
  90
  91         return 0;
  92 }
  93
  94 static struct clock_event_device owl_clockevent = {
  95         .name                   = "owl_tick",
  96         .rating                 = 200,
  97         .features               = CLOCK_EVT_FEAT_ONESHOT |
  98                                   CLOCK_EVT_FEAT_DYNIRQ,
  99         .set_state_shutdown     = owl_timer_set_state_shutdown,
 100         .set_state_oneshot      = owl_timer_set_state_oneshot,
 101         .tick_resume            = owl_timer_tick_resume,
 102         .set_next_event         = owl_timer_set_next_event,
 103 };
 104
 105 static irqreturn_t owl_timer1_interrupt(int irq, void *dev_id)
 106 {
 107         struct clock_event_device *evt = (struct clock_event_device *)dev_id;
 108
 109         writel(OWL_Tx_CTL_PD, owl_clkevt_base + OWL_Tx_CTL);
 110
 111         evt->event_handler(evt);
 112
 113         return IRQ_HANDLED;
 114 }
 115
 116 static int __init owl_timer_init(struct device_node *node)
 117 {
 118         struct clk *clk;
 119         unsigned long rate;
 120         int timer1_irq, ret;
 121
 122         owl_timer_base = of_io_request_and_map(node, 0, "owl-timer");
 123         if (IS_ERR(owl_timer_base)) {
 124                 pr_err("Can't map timer registers\n");
 125                 return PTR_ERR(owl_timer_base);
 126         }
 127
 128         owl_clksrc_base = owl_timer_base + 0x08;
 129         owl_clkevt_base = owl_timer_base + 0x14;
 130
 131         timer1_irq = of_irq_get_byname(node, "timer1");
 132         if (timer1_irq <= 0) {
 133                 pr_err("Can't parse timer1 IRQ\n");
 134                 return -EINVAL;
 135         }
 136
 137         clk = of_clk_get(node, 0);
 138         if (IS_ERR(clk))
 139                 return PTR_ERR(clk);
 140
 141         rate = clk_get_rate(clk);
 142
 143         owl_timer_reset(owl_clksrc_base);
 144         owl_timer_set_enabled(owl_clksrc_base, true);
 145
 146         sched_clock_register(owl_timer_sched_read, 32, rate);
 147         clocksource_mmio_init(owl_clksrc_base + OWL_Tx_VAL, node->name,
 148                               rate, 200, 32, clocksource_mmio_readl_up);
 149
 150         owl_timer_reset(owl_clkevt_base);
 151
 152         ret = request_irq(timer1_irq, owl_timer1_interrupt, IRQF_TIMER,
 153                           "owl-timer", &owl_clockevent);
 154         if (ret) {
 155                 pr_err("failed to request irq %d\n", timer1_irq);
 156                 return ret;
 157         }
 158
 159         owl_clockevent.cpumask = cpumask_of(0);
 160         owl_clockevent.irq = timer1_irq;
 161
 162         clockevents_config_and_register(&owl_clockevent, rate,
 163                                         0xf, 0xffffffff);
 164
 165         return 0;
 166 }
 167 TIMER_OF_DECLARE(owl_s500, "actions,s500-timer", owl_timer_init);
 168 TIMER_OF_DECLARE(owl_s700, "actions,s700-timer", owl_timer_init);
 169 TIMER_OF_DECLARE(owl_s900, "actions,s900-timer", owl_timer_init);