drivers/clocksource/timer-orion.c

   1 /*
   2  * Marvell Orion SoC timer handling.
   3  *
   4  * Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
   5  *
   6  * This file is licensed under the terms of the GNU General Public
   7  * License version 2.  This program is licensed "as is" without any
   8  * warranty of any kind, whether express or implied.
   9  *
  10  * Timer 0 is used as free-running clocksource, while timer 1 is
  11  * used as clock_event_device.
  12  */
  13
  14 #include <linux/kernel.h>
  15 #include <linux/bitops.h>
  16 #include <linux/clk.h>
  17 #include <linux/clockchips.h>
  18 #include <linux/delay.h>
  19 #include <linux/interrupt.h>
  20 #include <linux/of_address.h>
  21 #include <linux/of_irq.h>
  22 #include <linux/spinlock.h>
  23 #include <linux/sched_clock.h>
  24
  25 #define TIMER_CTRL              0x00
  26 #define  TIMER0_EN              BIT(0)
  27 #define  TIMER0_RELOAD_EN       BIT(1)
  28 #define  TIMER1_EN              BIT(2)
  29 #define  TIMER1_RELOAD_EN       BIT(3)
  30 #define TIMER0_RELOAD           0x10
  31 #define TIMER0_VAL              0x14
  32 #define TIMER1_RELOAD           0x18
  33 #define TIMER1_VAL              0x1c
  34
  35 #define ORION_ONESHOT_MIN       1
  36 #define ORION_ONESHOT_MAX       0xfffffffe
  37
  38 static void __iomem *timer_base;
  39
  40 static unsigned long notrace orion_read_timer(void)
  41 {
  42         return ~readl(timer_base + TIMER0_VAL);
  43 }
  44
  45 static struct delay_timer orion_delay_timer = {
  46         .read_current_timer = orion_read_timer,
  47 };
  48
  49 static void orion_delay_timer_init(unsigned long rate)
  50 {
  51         orion_delay_timer.freq = rate;
  52         register_current_timer_delay(&orion_delay_timer);
  53 }
  54
  55 /*
  56  * Free-running clocksource handling.
  57  */
  58 static u64 notrace orion_read_sched_clock(void)
  59 {
  60         return ~readl(timer_base + TIMER0_VAL);
  61 }
  62
  63 /*
  64  * Clockevent handling.
  65  */
  66 static u32 ticks_per_jiffy;
  67
  68 static int orion_clkevt_next_event(unsigned long delta,
  69                                    struct clock_event_device *dev)
  70 {
  71         /* setup and enable one-shot timer */
  72         writel(delta, timer_base + TIMER1_VAL);
  73         atomic_io_modify(timer_base + TIMER_CTRL,
  74                 TIMER1_RELOAD_EN | TIMER1_EN, TIMER1_EN);
  75
  76         return 0;
  77 }
  78
  79 static int orion_clkevt_shutdown(struct clock_event_device *dev)
  80 {
  81         /* disable timer */
  82         atomic_io_modify(timer_base + TIMER_CTRL,
  83                          TIMER1_RELOAD_EN | TIMER1_EN, 0);
  84         return 0;
  85 }
  86
  87 static int orion_clkevt_set_periodic(struct clock_event_device *dev)
  88 {
  89         /* setup and enable periodic timer at 1/HZ intervals */
  90         writel(ticks_per_jiffy - 1, timer_base + TIMER1_RELOAD);
  91         writel(ticks_per_jiffy - 1, timer_base + TIMER1_VAL);
  92         atomic_io_modify(timer_base + TIMER_CTRL,
  93                          TIMER1_RELOAD_EN | TIMER1_EN,
  94                          TIMER1_RELOAD_EN | TIMER1_EN);
  95         return 0;
  96 }
  97
  98 static struct clock_event_device orion_clkevt = {
  99         .name                   = "orion_event",
 100         .features               = CLOCK_EVT_FEAT_ONESHOT |
 101                                   CLOCK_EVT_FEAT_PERIODIC,
 102         .shift                  = 32,
 103         .rating                 = 300,
 104         .set_next_event         = orion_clkevt_next_event,
 105         .set_state_shutdown     = orion_clkevt_shutdown,
 106         .set_state_periodic     = orion_clkevt_set_periodic,
 107         .set_state_oneshot      = orion_clkevt_shutdown,
 108         .tick_resume            = orion_clkevt_shutdown,
 109 };
 110
 111 static irqreturn_t orion_clkevt_irq_handler(int irq, void *dev_id)
 112 {
 113         orion_clkevt.event_handler(&orion_clkevt);
 114         return IRQ_HANDLED;
 115 }
 116
 117 static int __init orion_timer_init(struct device_node *np)
 118 {
 119         unsigned long rate;
 120         struct clk *clk;
 121         int irq, ret;
 122
 123         /* timer registers are shared with watchdog timer */
 124         timer_base = of_iomap(np, 0);
 125         if (!timer_base) {
 126                 pr_err("%pOFn: unable to map resource\n", np);
 127                 return -ENXIO;
 128         }
 129
 130         clk = of_clk_get(np, 0);
 131         if (IS_ERR(clk)) {
 132                 pr_err("%pOFn: unable to get clk\n", np);
 133                 return PTR_ERR(clk);
 134         }
 135
 136         ret = clk_prepare_enable(clk);
 137         if (ret) {
 138                 pr_err("Failed to prepare clock\n");
 139                 return ret;
 140         }
 141
 142         /* we are only interested in timer1 irq */
 143         irq = irq_of_parse_and_map(np, 1);
 144         if (irq <= 0) {
 145                 pr_err("%pOFn: unable to parse timer1 irq\n", np);
 146                 ret = -EINVAL;
 147                 goto out_unprep_clk;
 148         }
 149
 150         rate = clk_get_rate(clk);
 151
 152         /* setup timer0 as free-running clocksource */
 153         writel(~0, timer_base + TIMER0_VAL);
 154         writel(~0, timer_base + TIMER0_RELOAD);
 155         atomic_io_modify(timer_base + TIMER_CTRL,
 156                 TIMER0_RELOAD_EN | TIMER0_EN,
 157                 TIMER0_RELOAD_EN | TIMER0_EN);
 158
 159         ret = clocksource_mmio_init(timer_base + TIMER0_VAL,
 160                                     "orion_clocksource", rate, 300, 32,
 161                                     clocksource_mmio_readl_down);
 162         if (ret) {
 163                 pr_err("Failed to initialize mmio timer\n");
 164                 goto out_unprep_clk;
 165         }
 166
 167         sched_clock_register(orion_read_sched_clock, 32, rate);
 168
 169         /* setup timer1 as clockevent timer */
 170         ret = request_irq(irq, orion_clkevt_irq_handler, IRQF_TIMER,
 171                           "orion_event", NULL);
 172         if (ret) {
 173                 pr_err("%pOFn: unable to setup irq\n", np);
 174                 goto out_unprep_clk;
 175         }
 176
 177         ticks_per_jiffy = (clk_get_rate(clk) + HZ/2) / HZ;
 178         orion_clkevt.cpumask = cpumask_of(0);
 179         orion_clkevt.irq = irq;
 180         clockevents_config_and_register(&orion_clkevt, rate,
 181                                         ORION_ONESHOT_MIN, ORION_ONESHOT_MAX);
 182
 183
 184         orion_delay_timer_init(rate);
 185
 186         return 0;
 187
 188 out_unprep_clk:
 189         clk_disable_unprepare(clk);
 190         return ret;
 191 }
 192 TIMER_OF_DECLARE(orion_timer, "marvell,orion-timer", orion_timer_init);