drivers/clocksource/timer-atlas7.c

   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
  41 static unsigned long atlas7_timer_rate;
  42
  43 static 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
  52 static u32 sirfsoc_timer_reg_val[SIRFSOC_TIMER_REG_CNT];
  53
  54 static void __iomem *sirfsoc_timer_base;
  55
  56 /* disable count and interrupt */
  57 static 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 */
  64 static 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 */
  71 static 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 */
  88 static cycle_t 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
 101 static 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 */
 121 static int sirfsoc_timer_shutdown(struct clock_event_device *evt)
 122 {
 123         sirfsoc_timer_count_disable(smp_processor_id());
 124         return 0;
 125 }
 126
 127 static 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
 135 static 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
 151 static struct clock_event_device __percpu *sirfsoc_clockevent;
 152
 153 static 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
 163 static struct irqaction sirfsoc_timer_irq = {
 164         .name = "sirfsoc_timer0",
 165         .flags = IRQF_TIMER | IRQF_NOBALANCING,
 166         .handler = sirfsoc_timer_interrupt,
 167 };
 168
 169 static struct irqaction sirfsoc_timer1_irq = {
 170         .name = "sirfsoc_timer1",
 171         .flags = IRQF_TIMER | IRQF_NOBALANCING,
 172         .handler = sirfsoc_timer_interrupt,
 173 };
 174
 175 static int sirfsoc_local_timer_setup(struct clock_event_device *ce)
 176 {
 177         int cpu = smp_processor_id();
 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->min_delta_ns = clockevent_delta2ns(2, ce);
 196         ce->cpumask = cpumask_of(cpu);
 197
 198         action->dev_id = ce;
 199         BUG_ON(setup_irq(ce->irq, action));
 200         irq_force_affinity(action->irq, cpumask_of(cpu));
 201
 202         clockevents_register_device(ce);
 203         return 0;
 204 }
 205
 206 static void sirfsoc_local_timer_stop(struct clock_event_device *ce)
 207 {
 208         int cpu = smp_processor_id();
 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 }
 217
 218 static int sirfsoc_cpu_notify(struct notifier_block *self,
 219                               unsigned long action, void *hcpu)
 220 {
 221         /*
 222          * Grab cpu pointer in each case to avoid spurious
 223          * preemptible warnings
 224          */
 225         switch (action & ~CPU_TASKS_FROZEN) {
 226         case CPU_STARTING:
 227                 sirfsoc_local_timer_setup(this_cpu_ptr(sirfsoc_clockevent));
 228                 break;
 229         case CPU_DYING:
 230                 sirfsoc_local_timer_stop(this_cpu_ptr(sirfsoc_clockevent));
 231                 break;
 232         }
 233
 234         return NOTIFY_OK;
 235 }
 236
 237 static struct notifier_block sirfsoc_cpu_nb = {
 238         .notifier_call = sirfsoc_cpu_notify,
 239 };
 240
 241 static void __init sirfsoc_clockevent_init(void)
 242 {
 243         sirfsoc_clockevent = alloc_percpu(struct clock_event_device);
 244         BUG_ON(!sirfsoc_clockevent);
 245
 246         BUG_ON(register_cpu_notifier(&sirfsoc_cpu_nb));
 247
 248         /* Immediately configure the timer on the boot CPU */
 249         sirfsoc_local_timer_setup(this_cpu_ptr(sirfsoc_clockevent));
 250 }
 251
 252 /* initialize the kernel jiffy timer source */
 253 static void __init sirfsoc_atlas7_timer_init(struct device_node *np)
 254 {
 255         struct clk *clk;
 256
 257         clk = of_clk_get(np, 0);
 258         BUG_ON(IS_ERR(clk));
 259
 260         BUG_ON(clk_prepare_enable(clk));
 261
 262         atlas7_timer_rate = clk_get_rate(clk);
 263
 264         /* timer dividers: 0, not divided */
 265         writel_relaxed(0, sirfsoc_timer_base + SIRFSOC_TIMER_64COUNTER_CTRL);
 266         writel_relaxed(0, sirfsoc_timer_base + SIRFSOC_TIMER_32COUNTER_0_CTRL);
 267         writel_relaxed(0, sirfsoc_timer_base + SIRFSOC_TIMER_32COUNTER_1_CTRL);
 268
 269         /* Initialize timer counters to 0 */
 270         writel_relaxed(0, sirfsoc_timer_base + SIRFSOC_TIMER_64COUNTER_LOAD_LO);
 271         writel_relaxed(0, sirfsoc_timer_base + SIRFSOC_TIMER_64COUNTER_LOAD_HI);
 272         writel_relaxed(readl_relaxed(sirfsoc_timer_base + SIRFSOC_TIMER_64COUNTER_CTRL) |
 273                 BIT(1) | BIT(0), sirfsoc_timer_base + SIRFSOC_TIMER_64COUNTER_CTRL);
 274         writel_relaxed(0, sirfsoc_timer_base + SIRFSOC_TIMER_COUNTER_0);
 275         writel_relaxed(0, sirfsoc_timer_base + SIRFSOC_TIMER_COUNTER_1);
 276
 277         /* Clear all interrupts */
 278         writel_relaxed(0xFFFF, sirfsoc_timer_base + SIRFSOC_TIMER_INTR_STATUS);
 279
 280         BUG_ON(clocksource_register_hz(&sirfsoc_clocksource, atlas7_timer_rate));
 281
 282         sirfsoc_clockevent_init();
 283 }
 284
 285 static void __init sirfsoc_of_timer_init(struct device_node *np)
 286 {
 287         sirfsoc_timer_base = of_iomap(np, 0);
 288         if (!sirfsoc_timer_base)
 289                 panic("unable to map timer cpu registers\n");
 290
 291         sirfsoc_timer_irq.irq = irq_of_parse_and_map(np, 0);
 292         if (!sirfsoc_timer_irq.irq)
 293                 panic("No irq passed for timer0 via DT\n");
 294
 295         sirfsoc_timer1_irq.irq = irq_of_parse_and_map(np, 1);
 296         if (!sirfsoc_timer1_irq.irq)
 297                 panic("No irq passed for timer1 via DT\n");
 298
 299         sirfsoc_atlas7_timer_init(np);
 300 }
 301 CLOCKSOURCE_OF_DECLARE(sirfsoc_atlas7_timer, "sirf,atlas7-tick", sirfsoc_of_timer_init);