drivers/clocksource/rockchip_timer.c

   1 /*
   2  * Rockchip timer support
   3  *
   4  * Copyright (C) Daniel Lezcano <daniel.lezcano@linaro.org>
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 as
   8  * published by the Free Software Foundation.
   9  */
  10 #include <linux/clk.h>
  11 #include <linux/clockchips.h>
  12 #include <linux/init.h>
  13 #include <linux/interrupt.h>
  14 #include <linux/of.h>
  15 #include <linux/of_address.h>
  16 #include <linux/of_irq.h>
  17
  18 #define TIMER_NAME "rk_timer"
  19
  20 #define TIMER_LOAD_COUNT0       0x00
  21 #define TIMER_LOAD_COUNT1       0x04
  22 #define TIMER_CONTROL_REG3288   0x10
  23 #define TIMER_CONTROL_REG3399   0x1c
  24 #define TIMER_INT_STATUS        0x18
  25
  26 #define TIMER_DISABLE           0x0
  27 #define TIMER_ENABLE            0x1
  28 #define TIMER_MODE_FREE_RUNNING                 (0 << 1)
  29 #define TIMER_MODE_USER_DEFINED_COUNT           (1 << 1)
  30 #define TIMER_INT_UNMASK                        (1 << 2)
  31
  32 struct bc_timer {
  33         struct clock_event_device ce;
  34         void __iomem *base;
  35         void __iomem *ctrl;
  36         u32 freq;
  37 };
  38
  39 static struct bc_timer bc_timer;
  40
  41 static inline struct bc_timer *rk_timer(struct clock_event_device *ce)
  42 {
  43         return container_of(ce, struct bc_timer, ce);
  44 }
  45
  46 static inline void __iomem *rk_base(struct clock_event_device *ce)
  47 {
  48         return rk_timer(ce)->base;
  49 }
  50
  51 static inline void __iomem *rk_ctrl(struct clock_event_device *ce)
  52 {
  53         return rk_timer(ce)->ctrl;
  54 }
  55
  56 static inline void rk_timer_disable(struct clock_event_device *ce)
  57 {
  58         writel_relaxed(TIMER_DISABLE, rk_ctrl(ce));
  59 }
  60
  61 static inline void rk_timer_enable(struct clock_event_device *ce, u32 flags)
  62 {
  63         writel_relaxed(TIMER_ENABLE | TIMER_INT_UNMASK | flags,
  64                        rk_ctrl(ce));
  65 }
  66
  67 static void rk_timer_update_counter(unsigned long cycles,
  68                                     struct clock_event_device *ce)
  69 {
  70         writel_relaxed(cycles, rk_base(ce) + TIMER_LOAD_COUNT0);
  71         writel_relaxed(0, rk_base(ce) + TIMER_LOAD_COUNT1);
  72 }
  73
  74 static void rk_timer_interrupt_clear(struct clock_event_device *ce)
  75 {
  76         writel_relaxed(1, rk_base(ce) + TIMER_INT_STATUS);
  77 }
  78
  79 static inline int rk_timer_set_next_event(unsigned long cycles,
  80                                           struct clock_event_device *ce)
  81 {
  82         rk_timer_disable(ce);
  83         rk_timer_update_counter(cycles, ce);
  84         rk_timer_enable(ce, TIMER_MODE_USER_DEFINED_COUNT);
  85         return 0;
  86 }
  87
  88 static int rk_timer_shutdown(struct clock_event_device *ce)
  89 {
  90         rk_timer_disable(ce);
  91         return 0;
  92 }
  93
  94 static int rk_timer_set_periodic(struct clock_event_device *ce)
  95 {
  96         rk_timer_disable(ce);
  97         rk_timer_update_counter(rk_timer(ce)->freq / HZ - 1, ce);
  98         rk_timer_enable(ce, TIMER_MODE_FREE_RUNNING);
  99         return 0;
 100 }
 101
 102 static irqreturn_t rk_timer_interrupt(int irq, void *dev_id)
 103 {
 104         struct clock_event_device *ce = dev_id;
 105
 106         rk_timer_interrupt_clear(ce);
 107
 108         if (clockevent_state_oneshot(ce))
 109                 rk_timer_disable(ce);
 110
 111         ce->event_handler(ce);
 112
 113         return IRQ_HANDLED;
 114 }
 115
 116 static int __init rk_timer_init(struct device_node *np, u32 ctrl_reg)
 117 {
 118         struct clock_event_device *ce = &bc_timer.ce;
 119         struct clk *timer_clk;
 120         struct clk *pclk;
 121         int ret = -EINVAL, irq;
 122
 123         bc_timer.base = of_iomap(np, 0);
 124         if (!bc_timer.base) {
 125                 pr_err("Failed to get base address for '%s'\n", TIMER_NAME);
 126                 return -ENXIO;
 127         }
 128         bc_timer.ctrl = bc_timer.base + ctrl_reg;
 129
 130         pclk = of_clk_get_by_name(np, "pclk");
 131         if (IS_ERR(pclk)) {
 132                 ret = PTR_ERR(pclk);
 133                 pr_err("Failed to get pclk for '%s'\n", TIMER_NAME);
 134                 goto out_unmap;
 135         }
 136
 137         ret = clk_prepare_enable(pclk);
 138         if (ret) {
 139                 pr_err("Failed to enable pclk for '%s'\n", TIMER_NAME);
 140                 goto out_unmap;
 141         }
 142
 143         timer_clk = of_clk_get_by_name(np, "timer");
 144         if (IS_ERR(timer_clk)) {
 145                 ret = PTR_ERR(timer_clk);
 146                 pr_err("Failed to get timer clock for '%s'\n", TIMER_NAME);
 147                 goto out_timer_clk;
 148         }
 149
 150         ret = clk_prepare_enable(timer_clk);
 151         if (ret) {
 152                 pr_err("Failed to enable timer clock\n");
 153                 goto out_timer_clk;
 154         }
 155
 156         bc_timer.freq = clk_get_rate(timer_clk);
 157
 158         irq = irq_of_parse_and_map(np, 0);
 159         if (!irq) {
 160                 ret = -EINVAL;
 161                 pr_err("Failed to map interrupts for '%s'\n", TIMER_NAME);
 162                 goto out_irq;
 163         }
 164
 165         ce->name = TIMER_NAME;
 166         ce->features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT |
 167                        CLOCK_EVT_FEAT_DYNIRQ;
 168         ce->set_next_event = rk_timer_set_next_event;
 169         ce->set_state_shutdown = rk_timer_shutdown;
 170         ce->set_state_periodic = rk_timer_set_periodic;
 171         ce->irq = irq;
 172         ce->cpumask = cpu_possible_mask;
 173         ce->rating = 250;
 174
 175         rk_timer_interrupt_clear(ce);
 176         rk_timer_disable(ce);
 177
 178         ret = request_irq(irq, rk_timer_interrupt, IRQF_TIMER, TIMER_NAME, ce);
 179         if (ret) {
 180                 pr_err("Failed to initialize '%s': %d\n", TIMER_NAME, ret);
 181                 goto out_irq;
 182         }
 183
 184         clockevents_config_and_register(ce, bc_timer.freq, 1, UINT_MAX);
 185
 186         return 0;
 187
 188 out_irq:
 189         clk_disable_unprepare(timer_clk);
 190 out_timer_clk:
 191         clk_disable_unprepare(pclk);
 192 out_unmap:
 193         iounmap(bc_timer.base);
 194
 195         return ret;
 196 }
 197
 198 static int __init rk3288_timer_init(struct device_node *np)
 199 {
 200         return rk_timer_init(np, TIMER_CONTROL_REG3288);
 201 }
 202
 203 static int __init rk3399_timer_init(struct device_node *np)
 204 {
 205         return rk_timer_init(np, TIMER_CONTROL_REG3399);
 206 }
 207
 208 CLOCKSOURCE_OF_DECLARE(rk3288_timer, "rockchip,rk3288-timer",
 209                        rk3288_timer_init);
 210 CLOCKSOURCE_OF_DECLARE(rk3399_timer, "rockchip,rk3399-timer",
 211                        rk3399_timer_init);