drivers/clocksource/time-armada-370-xp.c

   1 /*
   2  * Marvell Armada 370/XP SoC timer handling.
   3  *
   4  * Copyright (C) 2012 Marvell
   5  *
   6  * Lior Amsalem <alior@marvell.com>
   7  * Gregory CLEMENT <gregory.clement@free-electrons.com>
   8  * Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
   9  *
  10  * This file is licensed under the terms of the GNU General Public
  11  * License version 2.  This program is licensed "as is" without any
  12  * warranty of any kind, whether express or implied.
  13  *
  14  * Timer 0 is used as free-running clocksource, while timer 1 is
  15  * used as clock_event_device.
  16  */
  17
  18 #include <linux/init.h>
  19 #include <linux/platform_device.h>
  20 #include <linux/kernel.h>
  21 #include <linux/timer.h>
  22 #include <linux/clockchips.h>
  23 #include <linux/interrupt.h>
  24 #include <linux/of.h>
  25 #include <linux/of_irq.h>
  26 #include <linux/of_address.h>
  27 #include <linux/irq.h>
  28 #include <linux/module.h>
  29 #include <asm/sched_clock.h>
  30
  31 /*
  32  * Timer block registers.
  33  */
  34 #define TIMER_CTRL_OFF          0x0000
  35 #define  TIMER0_EN               0x0001
  36 #define  TIMER0_RELOAD_EN        0x0002
  37 #define  TIMER0_25MHZ            0x0800
  38 #define  TIMER0_DIV(div)         ((div) << 19)
  39 #define  TIMER1_EN               0x0004
  40 #define  TIMER1_RELOAD_EN        0x0008
  41 #define  TIMER1_25MHZ            0x1000
  42 #define  TIMER1_DIV(div)         ((div) << 22)
  43 #define TIMER_EVENTS_STATUS     0x0004
  44 #define  TIMER0_CLR_MASK         (~0x1)
  45 #define  TIMER1_CLR_MASK         (~0x100)
  46 #define TIMER0_RELOAD_OFF       0x0010
  47 #define TIMER0_VAL_OFF          0x0014
  48 #define TIMER1_RELOAD_OFF       0x0018
  49 #define TIMER1_VAL_OFF          0x001c
  50
  51 /* Global timers are connected to the coherency fabric clock, and the
  52    below divider reduces their incrementing frequency. */
  53 #define TIMER_DIVIDER_SHIFT     5
  54 #define TIMER_DIVIDER           (1 << TIMER_DIVIDER_SHIFT)
  55
  56 /*
  57  * SoC-specific data.
  58  */
  59 static void __iomem *timer_base;
  60 static int timer_irq;
  61
  62 /*
  63  * Number of timer ticks per jiffy.
  64  */
  65 static u32 ticks_per_jiffy;
  66
  67 static u32 notrace armada_370_xp_read_sched_clock(void)
  68 {
  69         return ~readl(timer_base + TIMER0_VAL_OFF);
  70 }
  71
  72 /*
  73  * Clockevent handling.
  74  */
  75 static int
  76 armada_370_xp_clkevt_next_event(unsigned long delta,
  77                                 struct clock_event_device *dev)
  78 {
  79         u32 u;
  80
  81         /*
  82          * Clear clockevent timer interrupt.
  83          */
  84         writel(TIMER1_CLR_MASK, timer_base + TIMER_EVENTS_STATUS);
  85
  86         /*
  87          * Setup new clockevent timer value.
  88          */
  89         writel(delta, timer_base + TIMER1_VAL_OFF);
  90
  91         /*
  92          * Enable the timer.
  93          */
  94         u = readl(timer_base + TIMER_CTRL_OFF);
  95         u = ((u & ~TIMER1_RELOAD_EN) | TIMER1_EN |
  96              TIMER1_DIV(TIMER_DIVIDER_SHIFT));
  97         writel(u, timer_base + TIMER_CTRL_OFF);
  98
  99         return 0;
 100 }
 101
 102 static void
 103 armada_370_xp_clkevt_mode(enum clock_event_mode mode,
 104                           struct clock_event_device *dev)
 105 {
 106         u32 u;
 107
 108         if (mode == CLOCK_EVT_MODE_PERIODIC) {
 109                 /*
 110                  * Setup timer to fire at 1/HZ intervals.
 111                  */
 112                 writel(ticks_per_jiffy - 1, timer_base + TIMER1_RELOAD_OFF);
 113                 writel(ticks_per_jiffy - 1, timer_base + TIMER1_VAL_OFF);
 114
 115                 /*
 116                  * Enable timer.
 117                  */
 118                 u = readl(timer_base + TIMER_CTRL_OFF);
 119
 120                 writel((u | TIMER1_EN | TIMER1_RELOAD_EN |
 121                         TIMER1_DIV(TIMER_DIVIDER_SHIFT)),
 122                        timer_base + TIMER_CTRL_OFF);
 123         } else {
 124                 /*
 125                  * Disable timer.
 126                  */
 127                 u = readl(timer_base + TIMER_CTRL_OFF);
 128                 writel(u & ~TIMER1_EN, timer_base + TIMER_CTRL_OFF);
 129
 130                 /*
 131                  * ACK pending timer interrupt.
 132                  */
 133                 writel(TIMER1_CLR_MASK, timer_base + TIMER_EVENTS_STATUS);
 134
 135         }
 136 }
 137
 138 static struct clock_event_device armada_370_xp_clkevt = {
 139         .name           = "armada_370_xp_tick",
 140         .features       = CLOCK_EVT_FEAT_ONESHOT | CLOCK_EVT_FEAT_PERIODIC,
 141         .shift          = 32,
 142         .rating         = 300,
 143         .set_next_event = armada_370_xp_clkevt_next_event,
 144         .set_mode       = armada_370_xp_clkevt_mode,
 145 };
 146
 147 static irqreturn_t armada_370_xp_timer_interrupt(int irq, void *dev_id)
 148 {
 149         /*
 150          * ACK timer interrupt and call event handler.
 151          */
 152
 153         writel(TIMER1_CLR_MASK, timer_base + TIMER_EVENTS_STATUS);
 154         armada_370_xp_clkevt.event_handler(&armada_370_xp_clkevt);
 155
 156         return IRQ_HANDLED;
 157 }
 158
 159 static struct irqaction armada_370_xp_timer_irq = {
 160         .name           = "armada_370_xp_tick",
 161         .flags          = IRQF_DISABLED | IRQF_TIMER,
 162         .handler        = armada_370_xp_timer_interrupt
 163 };
 164
 165 void __init armada_370_xp_timer_init(void)
 166 {
 167         u32 u;
 168         struct device_node *np;
 169         unsigned int timer_clk;
 170         int ret;
 171         np = of_find_compatible_node(NULL, NULL, "marvell,armada-370-xp-timer");
 172         timer_base = of_iomap(np, 0);
 173         WARN_ON(!timer_base);
 174
 175         if (of_find_property(np, "marvell,timer-25Mhz", NULL)) {
 176                 /* The fixed 25MHz timer is available so let's use it */
 177                 u = readl(timer_base + TIMER_CTRL_OFF);
 178                 writel(u | TIMER0_25MHZ | TIMER1_25MHZ,
 179                        timer_base + TIMER_CTRL_OFF);
 180                 timer_clk = 25000000;
 181         } else {
 182                 u32 clk = 0;
 183                 ret = of_property_read_u32(np, "clock-frequency", &clk);
 184                 WARN_ON(!clk || ret < 0);
 185                 u = readl(timer_base + TIMER_CTRL_OFF);
 186                 writel(u & ~(TIMER0_25MHZ | TIMER1_25MHZ),
 187                        timer_base + TIMER_CTRL_OFF);
 188                 timer_clk = clk / TIMER_DIVIDER;
 189         }
 190
 191         /* We use timer 0 as clocksource, and timer 1 for
 192            clockevents */
 193         timer_irq = irq_of_parse_and_map(np, 1);
 194
 195         ticks_per_jiffy = (timer_clk + HZ / 2) / HZ;
 196
 197         /*
 198          * Set scale and timer for sched_clock.
 199          */
 200         setup_sched_clock(armada_370_xp_read_sched_clock, 32, timer_clk);
 201
 202         /*
 203          * Setup free-running clocksource timer (interrupts
 204          * disabled).
 205          */
 206         writel(0xffffffff, timer_base + TIMER0_VAL_OFF);
 207         writel(0xffffffff, timer_base + TIMER0_RELOAD_OFF);
 208
 209         u = readl(timer_base + TIMER_CTRL_OFF);
 210
 211         writel((u | TIMER0_EN | TIMER0_RELOAD_EN |
 212                 TIMER0_DIV(TIMER_DIVIDER_SHIFT)), timer_base + TIMER_CTRL_OFF);
 213
 214         clocksource_mmio_init(timer_base + TIMER0_VAL_OFF,
 215                               "armada_370_xp_clocksource",
 216                               timer_clk, 300, 32, clocksource_mmio_readl_down);
 217
 218         /*
 219          * Setup clockevent timer (interrupt-driven).
 220          */
 221         setup_irq(timer_irq, &armada_370_xp_timer_irq);
 222         armada_370_xp_clkevt.cpumask = cpumask_of(0);
 223         clockevents_config_and_register(&armada_370_xp_clkevt,
 224                                         timer_clk, 1, 0xfffffffe);
 225 }
 226