drivers/clocksource/timer-marco.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 MARCO_CLOCK_FREQ 1000000
  24
  25 #define SIRFSOC_TIMER_32COUNTER_0_CTRL                  0x0000
  26 #define SIRFSOC_TIMER_32COUNTER_1_CTRL                  0x0004
  27 #define SIRFSOC_TIMER_MATCH_0                           0x0018
  28 #define SIRFSOC_TIMER_MATCH_1                           0x001c
  29 #define SIRFSOC_TIMER_COUNTER_0                         0x0048
  30 #define SIRFSOC_TIMER_COUNTER_1                         0x004c
  31 #define SIRFSOC_TIMER_INTR_STATUS                       0x0060
  32 #define SIRFSOC_TIMER_WATCHDOG_EN                       0x0064
  33 #define SIRFSOC_TIMER_64COUNTER_CTRL                    0x0068
  34 #define SIRFSOC_TIMER_64COUNTER_LO                      0x006c
  35 #define SIRFSOC_TIMER_64COUNTER_HI                      0x0070
  36 #define SIRFSOC_TIMER_64COUNTER_LOAD_LO                 0x0074
  37 #define SIRFSOC_TIMER_64COUNTER_LOAD_HI                 0x0078
  38 #define SIRFSOC_TIMER_64COUNTER_RLATCHED_LO             0x007c
  39 #define SIRFSOC_TIMER_64COUNTER_RLATCHED_HI             0x0080
  40
  41 #define SIRFSOC_TIMER_REG_CNT 6
  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) | 0x7,
  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 (ce->mode == CLOCK_EVT_MODE_ONESHOT)
  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         writel_relaxed(0, sirfsoc_timer_base + SIRFSOC_TIMER_COUNTER_0 +
 107                 4 * cpu);
 108         writel_relaxed(delta, sirfsoc_timer_base + SIRFSOC_TIMER_MATCH_0 +
 109                 4 * cpu);
 110
 111         /* enable the tick */
 112         sirfsoc_timer_count_enable(cpu);
 113
 114         return 0;
 115 }
 116
 117 static void sirfsoc_timer_set_mode(enum clock_event_mode mode,
 118         struct clock_event_device *ce)
 119 {
 120         switch (mode) {
 121         case CLOCK_EVT_MODE_ONESHOT:
 122                 /* enable in set_next_event */
 123                 break;
 124         default:
 125                 break;
 126         }
 127
 128         sirfsoc_timer_count_disable(smp_processor_id());
 129 }
 130
 131 static void sirfsoc_clocksource_suspend(struct clocksource *cs)
 132 {
 133         int i;
 134
 135         for (i = 0; i < SIRFSOC_TIMER_REG_CNT; i++)
 136                 sirfsoc_timer_reg_val[i] = readl_relaxed(sirfsoc_timer_base + sirfsoc_timer_reg_list[i]);
 137 }
 138
 139 static void sirfsoc_clocksource_resume(struct clocksource *cs)
 140 {
 141         int i;
 142
 143         for (i = 0; i < SIRFSOC_TIMER_REG_CNT - 2; i++)
 144                 writel_relaxed(sirfsoc_timer_reg_val[i], sirfsoc_timer_base + sirfsoc_timer_reg_list[i]);
 145
 146         writel_relaxed(sirfsoc_timer_reg_val[SIRFSOC_TIMER_REG_CNT - 2],
 147                 sirfsoc_timer_base + SIRFSOC_TIMER_64COUNTER_LOAD_LO);
 148         writel_relaxed(sirfsoc_timer_reg_val[SIRFSOC_TIMER_REG_CNT - 1],
 149                 sirfsoc_timer_base + SIRFSOC_TIMER_64COUNTER_LOAD_HI);
 150
 151         writel_relaxed(readl_relaxed(sirfsoc_timer_base + SIRFSOC_TIMER_64COUNTER_CTRL) |
 152                 BIT(1) | BIT(0), sirfsoc_timer_base + SIRFSOC_TIMER_64COUNTER_CTRL);
 153 }
 154
 155 static struct clock_event_device __percpu *sirfsoc_clockevent;
 156
 157 static struct clocksource sirfsoc_clocksource = {
 158         .name = "sirfsoc_clocksource",
 159         .rating = 200,
 160         .mask = CLOCKSOURCE_MASK(64),
 161         .flags = CLOCK_SOURCE_IS_CONTINUOUS,
 162         .read = sirfsoc_timer_read,
 163         .suspend = sirfsoc_clocksource_suspend,
 164         .resume = sirfsoc_clocksource_resume,
 165 };
 166
 167 static struct irqaction sirfsoc_timer_irq = {
 168         .name = "sirfsoc_timer0",
 169         .flags = IRQF_TIMER | IRQF_NOBALANCING,
 170         .handler = sirfsoc_timer_interrupt,
 171 };
 172
 173 static struct irqaction sirfsoc_timer1_irq = {
 174         .name = "sirfsoc_timer1",
 175         .flags = IRQF_TIMER | IRQF_NOBALANCING,
 176         .handler = sirfsoc_timer_interrupt,
 177 };
 178
 179 static int sirfsoc_local_timer_setup(struct clock_event_device *ce)
 180 {
 181         int cpu = smp_processor_id();
 182         struct irqaction *action;
 183
 184         if (cpu == 0)
 185                 action = &sirfsoc_timer_irq;
 186         else
 187                 action = &sirfsoc_timer1_irq;
 188
 189         ce->irq = action->irq;
 190         ce->name = "local_timer";
 191         ce->features = CLOCK_EVT_FEAT_ONESHOT;
 192         ce->rating = 200;
 193         ce->set_mode = sirfsoc_timer_set_mode;
 194         ce->set_next_event = sirfsoc_timer_set_next_event;
 195         clockevents_calc_mult_shift(ce, MARCO_CLOCK_FREQ, 60);
 196         ce->max_delta_ns = clockevent_delta2ns(-2, ce);
 197         ce->min_delta_ns = clockevent_delta2ns(2, ce);
 198         ce->cpumask = cpumask_of(cpu);
 199
 200         action->dev_id = ce;
 201         BUG_ON(setup_irq(ce->irq, action));
 202         irq_set_affinity(action->irq, cpumask_of(cpu));
 203
 204         clockevents_register_device(ce);
 205         return 0;
 206 }
 207
 208 static void sirfsoc_local_timer_stop(struct clock_event_device *ce)
 209 {
 210         int cpu = smp_processor_id();
 211
 212         sirfsoc_timer_count_disable(1);
 213
 214         if (cpu == 0)
 215                 remove_irq(sirfsoc_timer_irq.irq, &sirfsoc_timer_irq);
 216         else
 217                 remove_irq(sirfsoc_timer1_irq.irq, &sirfsoc_timer1_irq);
 218 }
 219
 220 static int sirfsoc_cpu_notify(struct notifier_block *self,
 221                               unsigned long action, void *hcpu)
 222 {
 223         /*
 224          * Grab cpu pointer in each case to avoid spurious
 225          * preemptible warnings
 226          */
 227         switch (action & ~CPU_TASKS_FROZEN) {
 228         case CPU_STARTING:
 229                 sirfsoc_local_timer_setup(this_cpu_ptr(sirfsoc_clockevent));
 230                 break;
 231         case CPU_DYING:
 232                 sirfsoc_local_timer_stop(this_cpu_ptr(sirfsoc_clockevent));
 233                 break;
 234         }
 235
 236         return NOTIFY_OK;
 237 }
 238
 239 static struct notifier_block sirfsoc_cpu_nb = {
 240         .notifier_call = sirfsoc_cpu_notify,
 241 };
 242
 243 static void __init sirfsoc_clockevent_init(void)
 244 {
 245         sirfsoc_clockevent = alloc_percpu(struct clock_event_device);
 246         BUG_ON(!sirfsoc_clockevent);
 247
 248         BUG_ON(register_cpu_notifier(&sirfsoc_cpu_nb));
 249
 250         /* Immediately configure the timer on the boot CPU */
 251         sirfsoc_local_timer_setup(this_cpu_ptr(sirfsoc_clockevent));
 252 }
 253
 254 /* initialize the kernel jiffy timer source */
 255 static void __init sirfsoc_marco_timer_init(void)
 256 {
 257         unsigned long rate;
 258         u32 timer_div;
 259         struct clk *clk;
 260
 261         /* timer's input clock is io clock */
 262         clk = clk_get_sys("io", NULL);
 263
 264         BUG_ON(IS_ERR(clk));
 265         rate = clk_get_rate(clk);
 266
 267         BUG_ON(rate < MARCO_CLOCK_FREQ);
 268         BUG_ON(rate % MARCO_CLOCK_FREQ);
 269
 270         /* Initialize the timer dividers */
 271         timer_div = rate / MARCO_CLOCK_FREQ - 1;
 272         writel_relaxed(timer_div << 16, sirfsoc_timer_base + SIRFSOC_TIMER_64COUNTER_CTRL);
 273         writel_relaxed(timer_div << 16, sirfsoc_timer_base + SIRFSOC_TIMER_32COUNTER_0_CTRL);
 274         writel_relaxed(timer_div << 16, sirfsoc_timer_base + SIRFSOC_TIMER_32COUNTER_1_CTRL);
 275
 276         /* Initialize timer counters to 0 */
 277         writel_relaxed(0, sirfsoc_timer_base + SIRFSOC_TIMER_64COUNTER_LOAD_LO);
 278         writel_relaxed(0, sirfsoc_timer_base + SIRFSOC_TIMER_64COUNTER_LOAD_HI);
 279         writel_relaxed(readl_relaxed(sirfsoc_timer_base + SIRFSOC_TIMER_64COUNTER_CTRL) |
 280                 BIT(1) | BIT(0), sirfsoc_timer_base + SIRFSOC_TIMER_64COUNTER_CTRL);
 281         writel_relaxed(0, sirfsoc_timer_base + SIRFSOC_TIMER_COUNTER_0);
 282         writel_relaxed(0, sirfsoc_timer_base + SIRFSOC_TIMER_COUNTER_1);
 283
 284         /* Clear all interrupts */
 285         writel_relaxed(0xFFFF, sirfsoc_timer_base + SIRFSOC_TIMER_INTR_STATUS);
 286
 287         BUG_ON(clocksource_register_hz(&sirfsoc_clocksource, MARCO_CLOCK_FREQ));
 288
 289         sirfsoc_clockevent_init();
 290 }
 291
 292 static void __init sirfsoc_of_timer_init(struct device_node *np)
 293 {
 294         sirfsoc_timer_base = of_iomap(np, 0);
 295         if (!sirfsoc_timer_base)
 296                 panic("unable to map timer cpu registers\n");
 297
 298         sirfsoc_timer_irq.irq = irq_of_parse_and_map(np, 0);
 299         if (!sirfsoc_timer_irq.irq)
 300                 panic("No irq passed for timer0 via DT\n");
 301
 302         sirfsoc_timer1_irq.irq = irq_of_parse_and_map(np, 1);
 303         if (!sirfsoc_timer1_irq.irq)
 304                 panic("No irq passed for timer1 via DT\n");
 305
 306         sirfsoc_marco_timer_init();
 307 }
 308 CLOCKSOURCE_OF_DECLARE(sirfsoc_marco_timer, "sirf,marco-tick", sirfsoc_of_timer_init );