| 1 | /* |
| 2 | * linux/arch/arm/kernel/smp_twd.c |
| 3 | * |
| 4 | * Copyright (C) 2002 ARM Ltd. |
| 5 | * All Rights Reserved |
| 6 | * |
| 7 | * This program is free software; you can redistribute it and/or modify |
| 8 | * it under the terms of the GNU General Public License version 2 as |
| 9 | * published by the Free Software Foundation. |
| 10 | */ |
| 11 | #include <linux/init.h> |
| 12 | #include <linux/kernel.h> |
| 13 | #include <linux/clk.h> |
| 14 | #include <linux/cpu.h> |
| 15 | #include <linux/delay.h> |
| 16 | #include <linux/device.h> |
| 17 | #include <linux/err.h> |
| 18 | #include <linux/smp.h> |
| 19 | #include <linux/jiffies.h> |
| 20 | #include <linux/clockchips.h> |
| 21 | #include <linux/interrupt.h> |
| 22 | #include <linux/io.h> |
| 23 | #include <linux/of_irq.h> |
| 24 | #include <linux/of_address.h> |
| 25 | |
| 26 | #include <asm/smp_twd.h> |
| 27 | |
| 28 | /* set up by the platform code */ |
| 29 | static void __iomem *twd_base; |
| 30 | |
| 31 | static struct clk *twd_clk; |
| 32 | static unsigned long twd_timer_rate; |
| 33 | static DEFINE_PER_CPU(bool, percpu_setup_called); |
| 34 | |
| 35 | static struct clock_event_device __percpu *twd_evt; |
| 36 | static unsigned int twd_features = |
| 37 | CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT; |
| 38 | static int twd_ppi; |
| 39 | |
| 40 | static int twd_shutdown(struct clock_event_device *clk) |
| 41 | { |
| 42 | writel_relaxed(0, twd_base + TWD_TIMER_CONTROL); |
| 43 | return 0; |
| 44 | } |
| 45 | |
| 46 | static int twd_set_oneshot(struct clock_event_device *clk) |
| 47 | { |
| 48 | /* period set, and timer enabled in 'next_event' hook */ |
| 49 | writel_relaxed(TWD_TIMER_CONTROL_IT_ENABLE | TWD_TIMER_CONTROL_ONESHOT, |
| 50 | twd_base + TWD_TIMER_CONTROL); |
| 51 | return 0; |
| 52 | } |
| 53 | |
| 54 | static int twd_set_periodic(struct clock_event_device *clk) |
| 55 | { |
| 56 | unsigned long ctrl = TWD_TIMER_CONTROL_ENABLE | |
| 57 | TWD_TIMER_CONTROL_IT_ENABLE | |
| 58 | TWD_TIMER_CONTROL_PERIODIC; |
| 59 | |
| 60 | writel_relaxed(DIV_ROUND_CLOSEST(twd_timer_rate, HZ), |
| 61 | twd_base + TWD_TIMER_LOAD); |
| 62 | writel_relaxed(ctrl, twd_base + TWD_TIMER_CONTROL); |
| 63 | return 0; |
| 64 | } |
| 65 | |
| 66 | static int twd_set_next_event(unsigned long evt, |
| 67 | struct clock_event_device *unused) |
| 68 | { |
| 69 | unsigned long ctrl = readl_relaxed(twd_base + TWD_TIMER_CONTROL); |
| 70 | |
| 71 | ctrl |= TWD_TIMER_CONTROL_ENABLE; |
| 72 | |
| 73 | writel_relaxed(evt, twd_base + TWD_TIMER_COUNTER); |
| 74 | writel_relaxed(ctrl, twd_base + TWD_TIMER_CONTROL); |
| 75 | |
| 76 | return 0; |
| 77 | } |
| 78 | |
| 79 | /* |
| 80 | * local_timer_ack: checks for a local timer interrupt. |
| 81 | * |
| 82 | * If a local timer interrupt has occurred, acknowledge and return 1. |
| 83 | * Otherwise, return 0. |
| 84 | */ |
| 85 | static int twd_timer_ack(void) |
| 86 | { |
| 87 | if (readl_relaxed(twd_base + TWD_TIMER_INTSTAT)) { |
| 88 | writel_relaxed(1, twd_base + TWD_TIMER_INTSTAT); |
| 89 | return 1; |
| 90 | } |
| 91 | |
| 92 | return 0; |
| 93 | } |
| 94 | |
| 95 | static void twd_timer_stop(void) |
| 96 | { |
| 97 | struct clock_event_device *clk = raw_cpu_ptr(twd_evt); |
| 98 | |
| 99 | twd_shutdown(clk); |
| 100 | disable_percpu_irq(clk->irq); |
| 101 | } |
| 102 | |
| 103 | #ifdef CONFIG_COMMON_CLK |
| 104 | |
| 105 | /* |
| 106 | * Updates clockevent frequency when the cpu frequency changes. |
| 107 | * Called on the cpu that is changing frequency with interrupts disabled. |
| 108 | */ |
| 109 | static void twd_update_frequency(void *new_rate) |
| 110 | { |
| 111 | twd_timer_rate = *((unsigned long *) new_rate); |
| 112 | |
| 113 | clockevents_update_freq(raw_cpu_ptr(twd_evt), twd_timer_rate); |
| 114 | } |
| 115 | |
| 116 | static int twd_rate_change(struct notifier_block *nb, |
| 117 | unsigned long flags, void *data) |
| 118 | { |
| 119 | struct clk_notifier_data *cnd = data; |
| 120 | |
| 121 | /* |
| 122 | * The twd clock events must be reprogrammed to account for the new |
| 123 | * frequency. The timer is local to a cpu, so cross-call to the |
| 124 | * changing cpu. |
| 125 | */ |
| 126 | if (flags == POST_RATE_CHANGE) |
| 127 | on_each_cpu(twd_update_frequency, |
| 128 | (void *)&cnd->new_rate, 1); |
| 129 | |
| 130 | return NOTIFY_OK; |
| 131 | } |
| 132 | |
| 133 | static struct notifier_block twd_clk_nb = { |
| 134 | .notifier_call = twd_rate_change, |
| 135 | }; |
| 136 | |
| 137 | static int twd_clk_init(void) |
| 138 | { |
| 139 | if (twd_evt && raw_cpu_ptr(twd_evt) && !IS_ERR(twd_clk)) |
| 140 | return clk_notifier_register(twd_clk, &twd_clk_nb); |
| 141 | |
| 142 | return 0; |
| 143 | } |
| 144 | core_initcall(twd_clk_init); |
| 145 | |
| 146 | #elif defined (CONFIG_CPU_FREQ) |
| 147 | |
| 148 | #include <linux/cpufreq.h> |
| 149 | |
| 150 | /* |
| 151 | * Updates clockevent frequency when the cpu frequency changes. |
| 152 | * Called on the cpu that is changing frequency with interrupts disabled. |
| 153 | */ |
| 154 | static void twd_update_frequency(void *data) |
| 155 | { |
| 156 | twd_timer_rate = clk_get_rate(twd_clk); |
| 157 | |
| 158 | clockevents_update_freq(raw_cpu_ptr(twd_evt), twd_timer_rate); |
| 159 | } |
| 160 | |
| 161 | static int twd_cpufreq_transition(struct notifier_block *nb, |
| 162 | unsigned long state, void *data) |
| 163 | { |
| 164 | struct cpufreq_freqs *freqs = data; |
| 165 | |
| 166 | /* |
| 167 | * The twd clock events must be reprogrammed to account for the new |
| 168 | * frequency. The timer is local to a cpu, so cross-call to the |
| 169 | * changing cpu. |
| 170 | */ |
| 171 | if (state == CPUFREQ_POSTCHANGE) |
| 172 | smp_call_function_single(freqs->cpu, twd_update_frequency, |
| 173 | NULL, 1); |
| 174 | |
| 175 | return NOTIFY_OK; |
| 176 | } |
| 177 | |
| 178 | static struct notifier_block twd_cpufreq_nb = { |
| 179 | .notifier_call = twd_cpufreq_transition, |
| 180 | }; |
| 181 | |
| 182 | static int twd_cpufreq_init(void) |
| 183 | { |
| 184 | if (twd_evt && raw_cpu_ptr(twd_evt) && !IS_ERR(twd_clk)) |
| 185 | return cpufreq_register_notifier(&twd_cpufreq_nb, |
| 186 | CPUFREQ_TRANSITION_NOTIFIER); |
| 187 | |
| 188 | return 0; |
| 189 | } |
| 190 | core_initcall(twd_cpufreq_init); |
| 191 | |
| 192 | #endif |
| 193 | |
| 194 | static void twd_calibrate_rate(void) |
| 195 | { |
| 196 | unsigned long count; |
| 197 | u64 waitjiffies; |
| 198 | |
| 199 | /* |
| 200 | * If this is the first time round, we need to work out how fast |
| 201 | * the timer ticks |
| 202 | */ |
| 203 | if (twd_timer_rate == 0) { |
| 204 | pr_info("Calibrating local timer... "); |
| 205 | |
| 206 | /* Wait for a tick to start */ |
| 207 | waitjiffies = get_jiffies_64() + 1; |
| 208 | |
| 209 | while (get_jiffies_64() < waitjiffies) |
| 210 | udelay(10); |
| 211 | |
| 212 | /* OK, now the tick has started, let's get the timer going */ |
| 213 | waitjiffies += 5; |
| 214 | |
| 215 | /* enable, no interrupt or reload */ |
| 216 | writel_relaxed(0x1, twd_base + TWD_TIMER_CONTROL); |
| 217 | |
| 218 | /* maximum value */ |
| 219 | writel_relaxed(0xFFFFFFFFU, twd_base + TWD_TIMER_COUNTER); |
| 220 | |
| 221 | while (get_jiffies_64() < waitjiffies) |
| 222 | udelay(10); |
| 223 | |
| 224 | count = readl_relaxed(twd_base + TWD_TIMER_COUNTER); |
| 225 | |
| 226 | twd_timer_rate = (0xFFFFFFFFU - count) * (HZ / 5); |
| 227 | |
| 228 | pr_cont("%lu.%02luMHz.\n", twd_timer_rate / 1000000, |
| 229 | (twd_timer_rate / 10000) % 100); |
| 230 | } |
| 231 | } |
| 232 | |
| 233 | static irqreturn_t twd_handler(int irq, void *dev_id) |
| 234 | { |
| 235 | struct clock_event_device *evt = dev_id; |
| 236 | |
| 237 | if (twd_timer_ack()) { |
| 238 | evt->event_handler(evt); |
| 239 | return IRQ_HANDLED; |
| 240 | } |
| 241 | |
| 242 | return IRQ_NONE; |
| 243 | } |
| 244 | |
| 245 | static void twd_get_clock(struct device_node *np) |
| 246 | { |
| 247 | int err; |
| 248 | |
| 249 | if (np) |
| 250 | twd_clk = of_clk_get(np, 0); |
| 251 | else |
| 252 | twd_clk = clk_get_sys("smp_twd", NULL); |
| 253 | |
| 254 | if (IS_ERR(twd_clk)) { |
| 255 | pr_err("smp_twd: clock not found %d\n", (int) PTR_ERR(twd_clk)); |
| 256 | return; |
| 257 | } |
| 258 | |
| 259 | err = clk_prepare_enable(twd_clk); |
| 260 | if (err) { |
| 261 | pr_err("smp_twd: clock failed to prepare+enable: %d\n", err); |
| 262 | clk_put(twd_clk); |
| 263 | return; |
| 264 | } |
| 265 | |
| 266 | twd_timer_rate = clk_get_rate(twd_clk); |
| 267 | } |
| 268 | |
| 269 | /* |
| 270 | * Setup the local clock events for a CPU. |
| 271 | */ |
| 272 | static void twd_timer_setup(void) |
| 273 | { |
| 274 | struct clock_event_device *clk = raw_cpu_ptr(twd_evt); |
| 275 | int cpu = smp_processor_id(); |
| 276 | |
| 277 | /* |
| 278 | * If the basic setup for this CPU has been done before don't |
| 279 | * bother with the below. |
| 280 | */ |
| 281 | if (per_cpu(percpu_setup_called, cpu)) { |
| 282 | writel_relaxed(0, twd_base + TWD_TIMER_CONTROL); |
| 283 | clockevents_register_device(clk); |
| 284 | enable_percpu_irq(clk->irq, 0); |
| 285 | return; |
| 286 | } |
| 287 | per_cpu(percpu_setup_called, cpu) = true; |
| 288 | |
| 289 | twd_calibrate_rate(); |
| 290 | |
| 291 | /* |
| 292 | * The following is done once per CPU the first time .setup() is |
| 293 | * called. |
| 294 | */ |
| 295 | writel_relaxed(0, twd_base + TWD_TIMER_CONTROL); |
| 296 | |
| 297 | clk->name = "local_timer"; |
| 298 | clk->features = twd_features; |
| 299 | clk->rating = 350; |
| 300 | clk->set_state_shutdown = twd_shutdown; |
| 301 | clk->set_state_periodic = twd_set_periodic; |
| 302 | clk->set_state_oneshot = twd_set_oneshot; |
| 303 | clk->tick_resume = twd_shutdown; |
| 304 | clk->set_next_event = twd_set_next_event; |
| 305 | clk->irq = twd_ppi; |
| 306 | clk->cpumask = cpumask_of(cpu); |
| 307 | |
| 308 | clockevents_config_and_register(clk, twd_timer_rate, |
| 309 | 0xf, 0xffffffff); |
| 310 | enable_percpu_irq(clk->irq, 0); |
| 311 | } |
| 312 | |
| 313 | static int twd_timer_cpu_notify(struct notifier_block *self, |
| 314 | unsigned long action, void *hcpu) |
| 315 | { |
| 316 | switch (action & ~CPU_TASKS_FROZEN) { |
| 317 | case CPU_STARTING: |
| 318 | twd_timer_setup(); |
| 319 | break; |
| 320 | case CPU_DYING: |
| 321 | twd_timer_stop(); |
| 322 | break; |
| 323 | } |
| 324 | |
| 325 | return NOTIFY_OK; |
| 326 | } |
| 327 | |
| 328 | static struct notifier_block twd_timer_cpu_nb = { |
| 329 | .notifier_call = twd_timer_cpu_notify, |
| 330 | }; |
| 331 | |
| 332 | static int __init twd_local_timer_common_register(struct device_node *np) |
| 333 | { |
| 334 | int err; |
| 335 | |
| 336 | twd_evt = alloc_percpu(struct clock_event_device); |
| 337 | if (!twd_evt) { |
| 338 | err = -ENOMEM; |
| 339 | goto out_free; |
| 340 | } |
| 341 | |
| 342 | err = request_percpu_irq(twd_ppi, twd_handler, "twd", twd_evt); |
| 343 | if (err) { |
| 344 | pr_err("twd: can't register interrupt %d (%d)\n", twd_ppi, err); |
| 345 | goto out_free; |
| 346 | } |
| 347 | |
| 348 | err = register_cpu_notifier(&twd_timer_cpu_nb); |
| 349 | if (err) |
| 350 | goto out_irq; |
| 351 | |
| 352 | twd_get_clock(np); |
| 353 | if (!of_property_read_bool(np, "always-on")) |
| 354 | twd_features |= CLOCK_EVT_FEAT_C3STOP; |
| 355 | |
| 356 | /* |
| 357 | * Immediately configure the timer on the boot CPU, unless we need |
| 358 | * jiffies to be incrementing to calibrate the rate in which case |
| 359 | * setup the timer in late_time_init. |
| 360 | */ |
| 361 | if (twd_timer_rate) |
| 362 | twd_timer_setup(); |
| 363 | else |
| 364 | late_time_init = twd_timer_setup; |
| 365 | |
| 366 | return 0; |
| 367 | |
| 368 | out_irq: |
| 369 | free_percpu_irq(twd_ppi, twd_evt); |
| 370 | out_free: |
| 371 | iounmap(twd_base); |
| 372 | twd_base = NULL; |
| 373 | free_percpu(twd_evt); |
| 374 | |
| 375 | return err; |
| 376 | } |
| 377 | |
| 378 | int __init twd_local_timer_register(struct twd_local_timer *tlt) |
| 379 | { |
| 380 | if (twd_base || twd_evt) |
| 381 | return -EBUSY; |
| 382 | |
| 383 | twd_ppi = tlt->res[1].start; |
| 384 | |
| 385 | twd_base = ioremap(tlt->res[0].start, resource_size(&tlt->res[0])); |
| 386 | if (!twd_base) |
| 387 | return -ENOMEM; |
| 388 | |
| 389 | return twd_local_timer_common_register(NULL); |
| 390 | } |
| 391 | |
| 392 | #ifdef CONFIG_OF |
| 393 | static void __init twd_local_timer_of_register(struct device_node *np) |
| 394 | { |
| 395 | int err; |
| 396 | |
| 397 | twd_ppi = irq_of_parse_and_map(np, 0); |
| 398 | if (!twd_ppi) { |
| 399 | err = -EINVAL; |
| 400 | goto out; |
| 401 | } |
| 402 | |
| 403 | twd_base = of_iomap(np, 0); |
| 404 | if (!twd_base) { |
| 405 | err = -ENOMEM; |
| 406 | goto out; |
| 407 | } |
| 408 | |
| 409 | err = twd_local_timer_common_register(np); |
| 410 | |
| 411 | out: |
| 412 | WARN(err, "twd_local_timer_of_register failed (%d)\n", err); |
| 413 | } |
| 414 | CLOCKSOURCE_OF_DECLARE(arm_twd_a9, "arm,cortex-a9-twd-timer", twd_local_timer_of_register); |
| 415 | CLOCKSOURCE_OF_DECLARE(arm_twd_a5, "arm,cortex-a5-twd-timer", twd_local_timer_of_register); |
| 416 | CLOCKSOURCE_OF_DECLARE(arm_twd_11mp, "arm,arm11mp-twd-timer", twd_local_timer_of_register); |
| 417 | #endif |