drivers/clocksource/qcom-timer.c

   1 /*
   2  *
   3  * Copyright (C) 2007 Google, Inc.
   4  * Copyright (c) 2009-2012,2014, The Linux Foundation. All rights reserved.
   5  *
   6  * This software is licensed under the terms of the GNU General Public
   7  * License version 2, as published by the Free Software Foundation, and
   8  * may be copied, distributed, and modified under those terms.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  *
  15  */
  16
  17 #include <linux/clocksource.h>
  18 #include <linux/clockchips.h>
  19 #include <linux/cpu.h>
  20 #include <linux/init.h>
  21 #include <linux/interrupt.h>
  22 #include <linux/irq.h>
  23 #include <linux/io.h>
  24 #include <linux/of.h>
  25 #include <linux/of_address.h>
  26 #include <linux/of_irq.h>
  27 #include <linux/sched_clock.h>
  28
  29 #include <asm/delay.h>
  30
  31 #define TIMER_MATCH_VAL                 0x0000
  32 #define TIMER_COUNT_VAL                 0x0004
  33 #define TIMER_ENABLE                    0x0008
  34 #define TIMER_ENABLE_CLR_ON_MATCH_EN    BIT(1)
  35 #define TIMER_ENABLE_EN                 BIT(0)
  36 #define TIMER_CLEAR                     0x000C
  37 #define DGT_CLK_CTL                     0x10
  38 #define DGT_CLK_CTL_DIV_4               0x3
  39 #define TIMER_STS_GPT0_CLR_PEND         BIT(10)
  40
  41 #define GPT_HZ 32768
  42
  43 static void __iomem *event_base;
  44 static void __iomem *sts_base;
  45
  46 static irqreturn_t msm_timer_interrupt(int irq, void *dev_id)
  47 {
  48         struct clock_event_device *evt = dev_id;
  49         /* Stop the timer tick */
  50         if (evt->mode == CLOCK_EVT_MODE_ONESHOT) {
  51                 u32 ctrl = readl_relaxed(event_base + TIMER_ENABLE);
  52                 ctrl &= ~TIMER_ENABLE_EN;
  53                 writel_relaxed(ctrl, event_base + TIMER_ENABLE);
  54         }
  55         evt->event_handler(evt);
  56         return IRQ_HANDLED;
  57 }
  58
  59 static int msm_timer_set_next_event(unsigned long cycles,
  60                                     struct clock_event_device *evt)
  61 {
  62         u32 ctrl = readl_relaxed(event_base + TIMER_ENABLE);
  63
  64         ctrl &= ~TIMER_ENABLE_EN;
  65         writel_relaxed(ctrl, event_base + TIMER_ENABLE);
  66
  67         writel_relaxed(ctrl, event_base + TIMER_CLEAR);
  68         writel_relaxed(cycles, event_base + TIMER_MATCH_VAL);
  69
  70         if (sts_base)
  71                 while (readl_relaxed(sts_base) & TIMER_STS_GPT0_CLR_PEND)
  72                         cpu_relax();
  73
  74         writel_relaxed(ctrl | TIMER_ENABLE_EN, event_base + TIMER_ENABLE);
  75         return 0;
  76 }
  77
  78 static void msm_timer_set_mode(enum clock_event_mode mode,
  79                               struct clock_event_device *evt)
  80 {
  81         u32 ctrl;
  82
  83         ctrl = readl_relaxed(event_base + TIMER_ENABLE);
  84         ctrl &= ~(TIMER_ENABLE_EN | TIMER_ENABLE_CLR_ON_MATCH_EN);
  85
  86         switch (mode) {
  87         case CLOCK_EVT_MODE_RESUME:
  88         case CLOCK_EVT_MODE_PERIODIC:
  89                 break;
  90         case CLOCK_EVT_MODE_ONESHOT:
  91                 /* Timer is enabled in set_next_event */
  92                 break;
  93         case CLOCK_EVT_MODE_UNUSED:
  94         case CLOCK_EVT_MODE_SHUTDOWN:
  95                 break;
  96         }
  97         writel_relaxed(ctrl, event_base + TIMER_ENABLE);
  98 }
  99
 100 static struct clock_event_device __percpu *msm_evt;
 101
 102 static void __iomem *source_base;
 103
 104 static notrace cycle_t msm_read_timer_count(struct clocksource *cs)
 105 {
 106         return readl_relaxed(source_base + TIMER_COUNT_VAL);
 107 }
 108
 109 static struct clocksource msm_clocksource = {
 110         .name   = "dg_timer",
 111         .rating = 300,
 112         .read   = msm_read_timer_count,
 113         .mask   = CLOCKSOURCE_MASK(32),
 114         .flags  = CLOCK_SOURCE_IS_CONTINUOUS,
 115 };
 116
 117 static int msm_timer_irq;
 118 static int msm_timer_has_ppi;
 119
 120 static int msm_local_timer_setup(struct clock_event_device *evt)
 121 {
 122         int cpu = smp_processor_id();
 123         int err;
 124
 125         evt->irq = msm_timer_irq;
 126         evt->name = "msm_timer";
 127         evt->features = CLOCK_EVT_FEAT_ONESHOT;
 128         evt->rating = 200;
 129         evt->set_mode = msm_timer_set_mode;
 130         evt->set_next_event = msm_timer_set_next_event;
 131         evt->cpumask = cpumask_of(cpu);
 132
 133         clockevents_config_and_register(evt, GPT_HZ, 4, 0xffffffff);
 134
 135         if (msm_timer_has_ppi) {
 136                 enable_percpu_irq(evt->irq, IRQ_TYPE_EDGE_RISING);
 137         } else {
 138                 err = request_irq(evt->irq, msm_timer_interrupt,
 139                                 IRQF_TIMER | IRQF_NOBALANCING |
 140                                 IRQF_TRIGGER_RISING, "gp_timer", evt);
 141                 if (err)
 142                         pr_err("request_irq failed\n");
 143         }
 144
 145         return 0;
 146 }
 147
 148 static void msm_local_timer_stop(struct clock_event_device *evt)
 149 {
 150         evt->set_mode(CLOCK_EVT_MODE_UNUSED, evt);
 151         disable_percpu_irq(evt->irq);
 152 }
 153
 154 static int msm_timer_cpu_notify(struct notifier_block *self,
 155                                            unsigned long action, void *hcpu)
 156 {
 157         /*
 158          * Grab cpu pointer in each case to avoid spurious
 159          * preemptible warnings
 160          */
 161         switch (action & ~CPU_TASKS_FROZEN) {
 162         case CPU_STARTING:
 163                 msm_local_timer_setup(this_cpu_ptr(msm_evt));
 164                 break;
 165         case CPU_DYING:
 166                 msm_local_timer_stop(this_cpu_ptr(msm_evt));
 167                 break;
 168         }
 169
 170         return NOTIFY_OK;
 171 }
 172
 173 static struct notifier_block msm_timer_cpu_nb = {
 174         .notifier_call = msm_timer_cpu_notify,
 175 };
 176
 177 static u64 notrace msm_sched_clock_read(void)
 178 {
 179         return msm_clocksource.read(&msm_clocksource);
 180 }
 181
 182 static unsigned long msm_read_current_timer(void)
 183 {
 184         return msm_clocksource.read(&msm_clocksource);
 185 }
 186
 187 static struct delay_timer msm_delay_timer = {
 188         .read_current_timer = msm_read_current_timer,
 189 };
 190
 191 static void __init msm_timer_init(u32 dgt_hz, int sched_bits, int irq,
 192                                   bool percpu)
 193 {
 194         struct clocksource *cs = &msm_clocksource;
 195         int res = 0;
 196
 197         msm_timer_irq = irq;
 198         msm_timer_has_ppi = percpu;
 199
 200         msm_evt = alloc_percpu(struct clock_event_device);
 201         if (!msm_evt) {
 202                 pr_err("memory allocation failed for clockevents\n");
 203                 goto err;
 204         }
 205
 206         if (percpu)
 207                 res = request_percpu_irq(irq, msm_timer_interrupt,
 208                                          "gp_timer", msm_evt);
 209
 210         if (res) {
 211                 pr_err("request_percpu_irq failed\n");
 212         } else {
 213                 res = register_cpu_notifier(&msm_timer_cpu_nb);
 214                 if (res) {
 215                         free_percpu_irq(irq, msm_evt);
 216                         goto err;
 217                 }
 218
 219                 /* Immediately configure the timer on the boot CPU */
 220                 msm_local_timer_setup(raw_cpu_ptr(msm_evt));
 221         }
 222
 223 err:
 224         writel_relaxed(TIMER_ENABLE_EN, source_base + TIMER_ENABLE);
 225         res = clocksource_register_hz(cs, dgt_hz);
 226         if (res)
 227                 pr_err("clocksource_register failed\n");
 228         sched_clock_register(msm_sched_clock_read, sched_bits, dgt_hz);
 229         msm_delay_timer.freq = dgt_hz;
 230         register_current_timer_delay(&msm_delay_timer);
 231 }
 232
 233 static void __init msm_dt_timer_init(struct device_node *np)
 234 {
 235         u32 freq;
 236         int irq;
 237         struct resource res;
 238         u32 percpu_offset;
 239         void __iomem *base;
 240         void __iomem *cpu0_base;
 241
 242         base = of_iomap(np, 0);
 243         if (!base) {
 244                 pr_err("Failed to map event base\n");
 245                 return;
 246         }
 247
 248         /* We use GPT0 for the clockevent */
 249         irq = irq_of_parse_and_map(np, 1);
 250         if (irq <= 0) {
 251                 pr_err("Can't get irq\n");
 252                 return;
 253         }
 254
 255         /* We use CPU0's DGT for the clocksource */
 256         if (of_property_read_u32(np, "cpu-offset", &percpu_offset))
 257                 percpu_offset = 0;
 258
 259         if (of_address_to_resource(np, 0, &res)) {
 260                 pr_err("Failed to parse DGT resource\n");
 261                 return;
 262         }
 263
 264         cpu0_base = ioremap(res.start + percpu_offset, resource_size(&res));
 265         if (!cpu0_base) {
 266                 pr_err("Failed to map source base\n");
 267                 return;
 268         }
 269
 270         if (of_property_read_u32(np, "clock-frequency", &freq)) {
 271                 pr_err("Unknown frequency\n");
 272                 return;
 273         }
 274
 275         event_base = base + 0x4;
 276         sts_base = base + 0x88;
 277         source_base = cpu0_base + 0x24;
 278         freq /= 4;
 279         writel_relaxed(DGT_CLK_CTL_DIV_4, source_base + DGT_CLK_CTL);
 280
 281         msm_timer_init(freq, 32, irq, !!percpu_offset);
 282 }
 283 CLOCKSOURCE_OF_DECLARE(kpss_timer, "qcom,kpss-timer", msm_dt_timer_init);
 284 CLOCKSOURCE_OF_DECLARE(scss_timer, "qcom,scss-timer", msm_dt_timer_init);