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/clk.h>
  22 #include <linux/timer.h>
  23 #include <linux/clockchips.h>
  24 #include <linux/interrupt.h>
  25 #include <linux/of.h>
  26 #include <linux/of_irq.h>
  27 #include <linux/of_address.h>
  28 #include <linux/irq.h>
  29 #include <linux/module.h>
  30 #include <asm/sched_clock.h>
  31
  32 /*
  33  * Timer block registers.
  34  */
  35 #define TIMER_CTRL_OFF          0x0000
  36 #define  TIMER0_EN               0x0001
  37 #define  TIMER0_RELOAD_EN        0x0002
  38 #define  TIMER0_25MHZ            0x0800
  39 #define  TIMER0_DIV(div)         ((div) << 19)
  40 #define  TIMER1_EN               0x0004
  41 #define  TIMER1_RELOAD_EN        0x0008
  42 #define  TIMER1_25MHZ            0x1000
  43 #define  TIMER1_DIV(div)         ((div) << 22)
  44 #define TIMER_EVENTS_STATUS     0x0004
  45 #define  TIMER0_CLR_MASK         (~0x1)
  46 #define  TIMER1_CLR_MASK         (~0x100)
  47 #define TIMER0_RELOAD_OFF       0x0010
  48 #define TIMER0_VAL_OFF          0x0014
  49 #define TIMER1_RELOAD_OFF       0x0018
  50 #define TIMER1_VAL_OFF          0x001c
  51
  52 /* Global timers are connected to the coherency fabric clock, and the
  53    below divider reduces their incrementing frequency. */
  54 #define TIMER_DIVIDER_SHIFT     5
  55 #define TIMER_DIVIDER           (1 << TIMER_DIVIDER_SHIFT)
  56
  57 /*
  58  * SoC-specific data.
  59  */
  60 static void __iomem *timer_base;
  61 static int timer_irq;
  62
  63 /*
  64  * Number of timer ticks per jiffy.
  65  */
  66 static u32 ticks_per_jiffy;
  67
  68 static u32 notrace armada_370_xp_read_sched_clock(void)
  69 {
  70         return ~readl(timer_base + TIMER0_VAL_OFF);
  71 }
  72
  73 /*
  74  * Clockevent handling.
  75  */
  76 static int
  77 armada_370_xp_clkevt_next_event(unsigned long delta,
  78                                 struct clock_event_device *dev)
  79 {
  80         u32 u;
  81
  82         /*
  83          * Clear clockevent timer interrupt.
  84          */
  85         writel(TIMER1_CLR_MASK, timer_base + TIMER_EVENTS_STATUS);
  86
  87         /*
  88          * Setup new clockevent timer value.
  89          */
  90         writel(delta, timer_base + TIMER1_VAL_OFF);
  91
  92         /*
  93          * Enable the timer.
  94          */
  95         u = readl(timer_base + TIMER_CTRL_OFF);
  96         u = ((u & ~TIMER1_RELOAD_EN) | TIMER1_EN |
  97              TIMER1_DIV(TIMER_DIVIDER_SHIFT));
  98         writel(u, timer_base + TIMER_CTRL_OFF);
  99
 100         return 0;
 101 }
 102
 103 static void
 104 armada_370_xp_clkevt_mode(enum clock_event_mode mode,
 105                           struct clock_event_device *dev)
 106 {
 107         u32 u;
 108
 109         if (mode == CLOCK_EVT_MODE_PERIODIC) {
 110                 /*
 111                  * Setup timer to fire at 1/HZ intervals.
 112                  */
 113                 writel(ticks_per_jiffy - 1, timer_base + TIMER1_RELOAD_OFF);
 114                 writel(ticks_per_jiffy - 1, timer_base + TIMER1_VAL_OFF);
 115
 116                 /*
 117                  * Enable timer.
 118                  */
 119                 u = readl(timer_base + TIMER_CTRL_OFF);
 120
 121                 writel((u | TIMER1_EN | TIMER1_RELOAD_EN |
 122                         TIMER1_DIV(TIMER_DIVIDER_SHIFT)),
 123                        timer_base + TIMER_CTRL_OFF);
 124         } else {
 125                 /*
 126                  * Disable timer.
 127                  */
 128                 u = readl(timer_base + TIMER_CTRL_OFF);
 129                 writel(u & ~TIMER1_EN, timer_base + TIMER_CTRL_OFF);
 130
 131                 /*
 132                  * ACK pending timer interrupt.
 133                  */
 134                 writel(TIMER1_CLR_MASK, timer_base + TIMER_EVENTS_STATUS);
 135
 136         }
 137 }
 138
 139 static struct clock_event_device armada_370_xp_clkevt = {
 140         .name           = "armada_370_xp_tick",
 141         .features       = CLOCK_EVT_FEAT_ONESHOT | CLOCK_EVT_FEAT_PERIODIC,
 142         .shift          = 32,
 143         .rating         = 300,
 144         .set_next_event = armada_370_xp_clkevt_next_event,
 145         .set_mode       = armada_370_xp_clkevt_mode,
 146 };
 147
 148 static irqreturn_t armada_370_xp_timer_interrupt(int irq, void *dev_id)
 149 {
 150         /*
 151          * ACK timer interrupt and call event handler.
 152          */
 153
 154         writel(TIMER1_CLR_MASK, timer_base + TIMER_EVENTS_STATUS);
 155         armada_370_xp_clkevt.event_handler(&armada_370_xp_clkevt);
 156
 157         return IRQ_HANDLED;
 158 }
 159
 160 static struct irqaction armada_370_xp_timer_irq = {
 161         .name           = "armada_370_xp_tick",
 162         .flags          = IRQF_DISABLED | IRQF_TIMER,
 163         .handler        = armada_370_xp_timer_interrupt
 164 };
 165
 166 void __init armada_370_xp_timer_init(void)
 167 {
 168         u32 u;
 169         struct device_node *np;
 170         unsigned int timer_clk;
 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                 unsigned long rate = 0;
 183                 struct clk *clk = of_clk_get(np, 0);
 184                 WARN_ON(IS_ERR(clk));
 185                 rate =  clk_get_rate(clk);
 186                 u = readl(timer_base + TIMER_CTRL_OFF);
 187                 writel(u & ~(TIMER0_25MHZ | TIMER1_25MHZ),
 188                        timer_base + TIMER_CTRL_OFF);
 189                 timer_clk = rate / TIMER_DIVIDER;
 190         }
 191
 192         /* We use timer 0 as clocksource, and timer 1 for
 193            clockevents */
 194         timer_irq = irq_of_parse_and_map(np, 1);
 195
 196         ticks_per_jiffy = (timer_clk + HZ / 2) / HZ;
 197
 198         /*
 199          * Set scale and timer for sched_clock.
 200          */
 201         setup_sched_clock(armada_370_xp_read_sched_clock, 32, timer_clk);
 202
 203         /*
 204          * Setup free-running clocksource timer (interrupts
 205          * disabled).
 206          */
 207         writel(0xffffffff, timer_base + TIMER0_VAL_OFF);
 208         writel(0xffffffff, timer_base + TIMER0_RELOAD_OFF);
 209
 210         u = readl(timer_base + TIMER_CTRL_OFF);
 211
 212         writel((u | TIMER0_EN | TIMER0_RELOAD_EN |
 213                 TIMER0_DIV(TIMER_DIVIDER_SHIFT)), timer_base + TIMER_CTRL_OFF);
 214
 215         clocksource_mmio_init(timer_base + TIMER0_VAL_OFF,
 216                               "armada_370_xp_clocksource",
 217                               timer_clk, 300, 32, clocksource_mmio_readl_down);
 218
 219         /*
 220          * Setup clockevent timer (interrupt-driven).
 221          */
 222         setup_irq(timer_irq, &armada_370_xp_timer_irq);
 223         armada_370_xp_clkevt.cpumask = cpumask_of(0);
 224         clockevents_config_and_register(&armada_370_xp_clkevt,
 225                                         timer_clk, 1, 0xfffffffe);
 226 }
 227