linux/drivers/clocksource/timer-atlas7.c
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   1/*
   2 * System timer for CSR SiRFprimaII
   3 *
   4 * Copyright (c) 2011 Cambridge Silicon Radio Limited, a CSR plc group company.
   5 *
   6 * Licensed under GPLv2 or later.
   7 */
   8
   9#include <linux/kernel.h>
  10#include <linux/interrupt.h>
  11#include <linux/clockchips.h>
  12#include <linux/clocksource.h>
  13#include <linux/cpu.h>
  14#include <linux/bitops.h>
  15#include <linux/irq.h>
  16#include <linux/clk.h>
  17#include <linux/slab.h>
  18#include <linux/of.h>
  19#include <linux/of_irq.h>
  20#include <linux/of_address.h>
  21#include <linux/sched_clock.h>
  22
  23#define SIRFSOC_TIMER_32COUNTER_0_CTRL                  0x0000
  24#define SIRFSOC_TIMER_32COUNTER_1_CTRL                  0x0004
  25#define SIRFSOC_TIMER_MATCH_0                           0x0018
  26#define SIRFSOC_TIMER_MATCH_1                           0x001c
  27#define SIRFSOC_TIMER_COUNTER_0                         0x0048
  28#define SIRFSOC_TIMER_COUNTER_1                         0x004c
  29#define SIRFSOC_TIMER_INTR_STATUS                       0x0060
  30#define SIRFSOC_TIMER_WATCHDOG_EN                       0x0064
  31#define SIRFSOC_TIMER_64COUNTER_CTRL                    0x0068
  32#define SIRFSOC_TIMER_64COUNTER_LO                      0x006c
  33#define SIRFSOC_TIMER_64COUNTER_HI                      0x0070
  34#define SIRFSOC_TIMER_64COUNTER_LOAD_LO                 0x0074
  35#define SIRFSOC_TIMER_64COUNTER_LOAD_HI                 0x0078
  36#define SIRFSOC_TIMER_64COUNTER_RLATCHED_LO             0x007c
  37#define SIRFSOC_TIMER_64COUNTER_RLATCHED_HI             0x0080
  38
  39#define SIRFSOC_TIMER_REG_CNT 6
  40
  41static unsigned long atlas7_timer_rate;
  42
  43static const u32 sirfsoc_timer_reg_list[SIRFSOC_TIMER_REG_CNT] = {
  44        SIRFSOC_TIMER_WATCHDOG_EN,
  45        SIRFSOC_TIMER_32COUNTER_0_CTRL,
  46        SIRFSOC_TIMER_32COUNTER_1_CTRL,
  47        SIRFSOC_TIMER_64COUNTER_CTRL,
  48        SIRFSOC_TIMER_64COUNTER_RLATCHED_LO,
  49        SIRFSOC_TIMER_64COUNTER_RLATCHED_HI,
  50};
  51
  52static u32 sirfsoc_timer_reg_val[SIRFSOC_TIMER_REG_CNT];
  53
  54static void __iomem *sirfsoc_timer_base;
  55
  56/* disable count and interrupt */
  57static inline void sirfsoc_timer_count_disable(int idx)
  58{
  59        writel_relaxed(readl_relaxed(sirfsoc_timer_base + SIRFSOC_TIMER_32COUNTER_0_CTRL + 4 * idx) & ~0x7,
  60                sirfsoc_timer_base + SIRFSOC_TIMER_32COUNTER_0_CTRL + 4 * idx);
  61}
  62
  63/* enable count and interrupt */
  64static inline void sirfsoc_timer_count_enable(int idx)
  65{
  66        writel_relaxed(readl_relaxed(sirfsoc_timer_base + SIRFSOC_TIMER_32COUNTER_0_CTRL + 4 * idx) | 0x3,
  67                sirfsoc_timer_base + SIRFSOC_TIMER_32COUNTER_0_CTRL + 4 * idx);
  68}
  69
  70/* timer interrupt handler */
  71static irqreturn_t sirfsoc_timer_interrupt(int irq, void *dev_id)
  72{
  73        struct clock_event_device *ce = dev_id;
  74        int cpu = smp_processor_id();
  75
  76        /* clear timer interrupt */
  77        writel_relaxed(BIT(cpu), sirfsoc_timer_base + SIRFSOC_TIMER_INTR_STATUS);
  78
  79        if (clockevent_state_oneshot(ce))
  80                sirfsoc_timer_count_disable(cpu);
  81
  82        ce->event_handler(ce);
  83
  84        return IRQ_HANDLED;
  85}
  86
  87/* read 64-bit timer counter */
  88static u64 sirfsoc_timer_read(struct clocksource *cs)
  89{
  90        u64 cycles;
  91
  92        writel_relaxed((readl_relaxed(sirfsoc_timer_base + SIRFSOC_TIMER_64COUNTER_CTRL) |
  93                        BIT(0)) & ~BIT(1), sirfsoc_timer_base + SIRFSOC_TIMER_64COUNTER_CTRL);
  94
  95        cycles = readl_relaxed(sirfsoc_timer_base + SIRFSOC_TIMER_64COUNTER_RLATCHED_HI);
  96        cycles = (cycles << 32) | readl_relaxed(sirfsoc_timer_base + SIRFSOC_TIMER_64COUNTER_RLATCHED_LO);
  97
  98        return cycles;
  99}
 100
 101static int sirfsoc_timer_set_next_event(unsigned long delta,
 102        struct clock_event_device *ce)
 103{
 104        int cpu = smp_processor_id();
 105
 106        /* disable timer first, then modify the related registers */
 107        sirfsoc_timer_count_disable(cpu);
 108
 109        writel_relaxed(0, sirfsoc_timer_base + SIRFSOC_TIMER_COUNTER_0 +
 110                4 * cpu);
 111        writel_relaxed(delta, sirfsoc_timer_base + SIRFSOC_TIMER_MATCH_0 +
 112                4 * cpu);
 113
 114        /* enable the tick */
 115        sirfsoc_timer_count_enable(cpu);
 116
 117        return 0;
 118}
 119
 120/* Oneshot is enabled in set_next_event */
 121static int sirfsoc_timer_shutdown(struct clock_event_device *evt)
 122{
 123        sirfsoc_timer_count_disable(smp_processor_id());
 124        return 0;
 125}
 126
 127static void sirfsoc_clocksource_suspend(struct clocksource *cs)
 128{
 129        int i;
 130
 131        for (i = 0; i < SIRFSOC_TIMER_REG_CNT; i++)
 132                sirfsoc_timer_reg_val[i] = readl_relaxed(sirfsoc_timer_base + sirfsoc_timer_reg_list[i]);
 133}
 134
 135static void sirfsoc_clocksource_resume(struct clocksource *cs)
 136{
 137        int i;
 138
 139        for (i = 0; i < SIRFSOC_TIMER_REG_CNT - 2; i++)
 140                writel_relaxed(sirfsoc_timer_reg_val[i], sirfsoc_timer_base + sirfsoc_timer_reg_list[i]);
 141
 142        writel_relaxed(sirfsoc_timer_reg_val[SIRFSOC_TIMER_REG_CNT - 2],
 143                sirfsoc_timer_base + SIRFSOC_TIMER_64COUNTER_LOAD_LO);
 144        writel_relaxed(sirfsoc_timer_reg_val[SIRFSOC_TIMER_REG_CNT - 1],
 145                sirfsoc_timer_base + SIRFSOC_TIMER_64COUNTER_LOAD_HI);
 146
 147        writel_relaxed(readl_relaxed(sirfsoc_timer_base + SIRFSOC_TIMER_64COUNTER_CTRL) |
 148                BIT(1) | BIT(0), sirfsoc_timer_base + SIRFSOC_TIMER_64COUNTER_CTRL);
 149}
 150
 151static struct clock_event_device __percpu *sirfsoc_clockevent;
 152
 153static struct clocksource sirfsoc_clocksource = {
 154        .name = "sirfsoc_clocksource",
 155        .rating = 200,
 156        .mask = CLOCKSOURCE_MASK(64),
 157        .flags = CLOCK_SOURCE_IS_CONTINUOUS,
 158        .read = sirfsoc_timer_read,
 159        .suspend = sirfsoc_clocksource_suspend,
 160        .resume = sirfsoc_clocksource_resume,
 161};
 162
 163static struct irqaction sirfsoc_timer_irq = {
 164        .name = "sirfsoc_timer0",
 165        .flags = IRQF_TIMER | IRQF_NOBALANCING,
 166        .handler = sirfsoc_timer_interrupt,
 167};
 168
 169static struct irqaction sirfsoc_timer1_irq = {
 170        .name = "sirfsoc_timer1",
 171        .flags = IRQF_TIMER | IRQF_NOBALANCING,
 172        .handler = sirfsoc_timer_interrupt,
 173};
 174
 175static int sirfsoc_local_timer_starting_cpu(unsigned int cpu)
 176{
 177        struct clock_event_device *ce = per_cpu_ptr(sirfsoc_clockevent, cpu);
 178        struct irqaction *action;
 179
 180        if (cpu == 0)
 181                action = &sirfsoc_timer_irq;
 182        else
 183                action = &sirfsoc_timer1_irq;
 184
 185        ce->irq = action->irq;
 186        ce->name = "local_timer";
 187        ce->features = CLOCK_EVT_FEAT_ONESHOT;
 188        ce->rating = 200;
 189        ce->set_state_shutdown = sirfsoc_timer_shutdown;
 190        ce->set_state_oneshot = sirfsoc_timer_shutdown;
 191        ce->tick_resume = sirfsoc_timer_shutdown;
 192        ce->set_next_event = sirfsoc_timer_set_next_event;
 193        clockevents_calc_mult_shift(ce, atlas7_timer_rate, 60);
 194        ce->max_delta_ns = clockevent_delta2ns(-2, ce);
 195        ce->max_delta_ticks = (unsigned long)-2;
 196        ce->min_delta_ns = clockevent_delta2ns(2, ce);
 197        ce->min_delta_ticks = 2;
 198        ce->cpumask = cpumask_of(cpu);
 199
 200        action->dev_id = ce;
 201        BUG_ON(setup_irq(ce->irq, action));
 202        irq_force_affinity(action->irq, cpumask_of(cpu));
 203
 204        clockevents_register_device(ce);
 205        return 0;
 206}
 207
 208static int sirfsoc_local_timer_dying_cpu(unsigned int cpu)
 209{
 210        sirfsoc_timer_count_disable(1);
 211
 212        if (cpu == 0)
 213                remove_irq(sirfsoc_timer_irq.irq, &sirfsoc_timer_irq);
 214        else
 215                remove_irq(sirfsoc_timer1_irq.irq, &sirfsoc_timer1_irq);
 216        return 0;
 217}
 218
 219static int __init sirfsoc_clockevent_init(void)
 220{
 221        sirfsoc_clockevent = alloc_percpu(struct clock_event_device);
 222        BUG_ON(!sirfsoc_clockevent);
 223
 224        /* Install and invoke hotplug callbacks */
 225        return cpuhp_setup_state(CPUHP_AP_MARCO_TIMER_STARTING,
 226                                 "clockevents/marco:starting",
 227                                 sirfsoc_local_timer_starting_cpu,
 228                                 sirfsoc_local_timer_dying_cpu);
 229}
 230
 231/* initialize the kernel jiffy timer source */
 232static int __init sirfsoc_atlas7_timer_init(struct device_node *np)
 233{
 234        struct clk *clk;
 235
 236        clk = of_clk_get(np, 0);
 237        BUG_ON(IS_ERR(clk));
 238
 239        BUG_ON(clk_prepare_enable(clk));
 240
 241        atlas7_timer_rate = clk_get_rate(clk);
 242
 243        /* timer dividers: 0, not divided */
 244        writel_relaxed(0, sirfsoc_timer_base + SIRFSOC_TIMER_64COUNTER_CTRL);
 245        writel_relaxed(0, sirfsoc_timer_base + SIRFSOC_TIMER_32COUNTER_0_CTRL);
 246        writel_relaxed(0, sirfsoc_timer_base + SIRFSOC_TIMER_32COUNTER_1_CTRL);
 247
 248        /* Initialize timer counters to 0 */
 249        writel_relaxed(0, sirfsoc_timer_base + SIRFSOC_TIMER_64COUNTER_LOAD_LO);
 250        writel_relaxed(0, sirfsoc_timer_base + SIRFSOC_TIMER_64COUNTER_LOAD_HI);
 251        writel_relaxed(readl_relaxed(sirfsoc_timer_base + SIRFSOC_TIMER_64COUNTER_CTRL) |
 252                BIT(1) | BIT(0), sirfsoc_timer_base + SIRFSOC_TIMER_64COUNTER_CTRL);
 253        writel_relaxed(0, sirfsoc_timer_base + SIRFSOC_TIMER_COUNTER_0);
 254        writel_relaxed(0, sirfsoc_timer_base + SIRFSOC_TIMER_COUNTER_1);
 255
 256        /* Clear all interrupts */
 257        writel_relaxed(0xFFFF, sirfsoc_timer_base + SIRFSOC_TIMER_INTR_STATUS);
 258
 259        BUG_ON(clocksource_register_hz(&sirfsoc_clocksource, atlas7_timer_rate));
 260
 261        return sirfsoc_clockevent_init();
 262}
 263
 264static int __init sirfsoc_of_timer_init(struct device_node *np)
 265{
 266        sirfsoc_timer_base = of_iomap(np, 0);
 267        if (!sirfsoc_timer_base) {
 268                pr_err("unable to map timer cpu registers\n");
 269                return -ENXIO;
 270        }
 271
 272        sirfsoc_timer_irq.irq = irq_of_parse_and_map(np, 0);
 273        if (!sirfsoc_timer_irq.irq) {
 274                pr_err("No irq passed for timer0 via DT\n");
 275                return -EINVAL;
 276        }
 277
 278        sirfsoc_timer1_irq.irq = irq_of_parse_and_map(np, 1);
 279        if (!sirfsoc_timer1_irq.irq) {
 280                pr_err("No irq passed for timer1 via DT\n");
 281                return -EINVAL;
 282        }
 283
 284        return sirfsoc_atlas7_timer_init(np);
 285}
 286TIMER_OF_DECLARE(sirfsoc_atlas7_timer, "sirf,atlas7-tick", sirfsoc_of_timer_init);
 287