kernel/drivers/clocksource/timer-sp804.c

   1 /*
   2  *  linux/drivers/clocksource/timer-sp.c
   3  *
   4  *  Copyright (C) 1999 - 2003 ARM Limited
   5  *  Copyright (C) 2000 Deep Blue Solutions Ltd
   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 as published by
   9  * the Free Software Foundation; either version 2 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with this program; if not, write to the Free Software
  19  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  20  */
  21 #include <linux/clk.h>
  22 #include <linux/clocksource.h>
  23 #include <linux/clockchips.h>
  24 #include <linux/err.h>
  25 #include <linux/interrupt.h>
  26 #include <linux/irq.h>
  27 #include <linux/io.h>
  28 #include <linux/of.h>
  29 #include <linux/of_address.h>
  30 #include <linux/of_irq.h>
  31 #include <linux/sched_clock.h>
  32
  33 #include <clocksource/timer-sp804.h>
  34
  35 #include "timer-sp.h"
  36
  37 static long __init sp804_get_clock_rate(struct clk *clk)
  38 {
  39         long rate;
  40         int err;
  41
  42         err = clk_prepare(clk);
  43         if (err) {
  44                 pr_err("sp804: clock failed to prepare: %d\n", err);
  45                 clk_put(clk);
  46                 return err;
  47         }
  48
  49         err = clk_enable(clk);
  50         if (err) {
  51                 pr_err("sp804: clock failed to enable: %d\n", err);
  52                 clk_unprepare(clk);
  53                 clk_put(clk);
  54                 return err;
  55         }
  56
  57         rate = clk_get_rate(clk);
  58         if (rate < 0) {
  59                 pr_err("sp804: clock failed to get rate: %ld\n", rate);
  60                 clk_disable(clk);
  61                 clk_unprepare(clk);
  62                 clk_put(clk);
  63         }
  64
  65         return rate;
  66 }
  67
  68 static void __iomem *sched_clock_base;
  69
  70 static u64 notrace sp804_read(void)
  71 {
  72         return ~readl_relaxed(sched_clock_base + TIMER_VALUE);
  73 }
  74
  75 void __init sp804_timer_disable(void __iomem *base)
  76 {
  77         writel(0, base + TIMER_CTRL);
  78 }
  79
  80 void __init __sp804_clocksource_and_sched_clock_init(void __iomem *base,
  81                                                      const char *name,
  82                                                      struct clk *clk,
  83                                                      int use_sched_clock)
  84 {
  85         long rate;
  86
  87         if (!clk) {
  88                 clk = clk_get_sys("sp804", name);
  89                 if (IS_ERR(clk)) {
  90                         pr_err("sp804: clock not found: %d\n",
  91                                (int)PTR_ERR(clk));
  92                         return;
  93                 }
  94         }
  95
  96         rate = sp804_get_clock_rate(clk);
  97
  98         if (rate < 0)
  99                 return;
 100
 101         /* setup timer 0 as free-running clocksource */
 102         writel(0, base + TIMER_CTRL);
 103         writel(0xffffffff, base + TIMER_LOAD);
 104         writel(0xffffffff, base + TIMER_VALUE);
 105         writel(TIMER_CTRL_32BIT | TIMER_CTRL_ENABLE | TIMER_CTRL_PERIODIC,
 106                 base + TIMER_CTRL);
 107
 108         clocksource_mmio_init(base + TIMER_VALUE, name,
 109                 rate, 200, 32, clocksource_mmio_readl_down);
 110
 111         if (use_sched_clock) {
 112                 sched_clock_base = base;
 113                 sched_clock_register(sp804_read, 32, rate);
 114         }
 115 }
 116
 117
 118 static void __iomem *clkevt_base;
 119 static unsigned long clkevt_reload;
 120
 121 /*
 122  * IRQ handler for the timer
 123  */
 124 static irqreturn_t sp804_timer_interrupt(int irq, void *dev_id)
 125 {
 126         struct clock_event_device *evt = dev_id;
 127
 128         /* clear the interrupt */
 129         writel(1, clkevt_base + TIMER_INTCLR);
 130
 131         evt->event_handler(evt);
 132
 133         return IRQ_HANDLED;
 134 }
 135
 136 static inline void timer_shutdown(struct clock_event_device *evt)
 137 {
 138         writel(0, clkevt_base + TIMER_CTRL);
 139 }
 140
 141 static int sp804_shutdown(struct clock_event_device *evt)
 142 {
 143         timer_shutdown(evt);
 144         return 0;
 145 }
 146
 147 static int sp804_set_periodic(struct clock_event_device *evt)
 148 {
 149         unsigned long ctrl = TIMER_CTRL_32BIT | TIMER_CTRL_IE |
 150                              TIMER_CTRL_PERIODIC | TIMER_CTRL_ENABLE;
 151
 152         timer_shutdown(evt);
 153         writel(clkevt_reload, clkevt_base + TIMER_LOAD);
 154         writel(ctrl, clkevt_base + TIMER_CTRL);
 155         return 0;
 156 }
 157
 158 static int sp804_set_next_event(unsigned long next,
 159         struct clock_event_device *evt)
 160 {
 161         unsigned long ctrl = TIMER_CTRL_32BIT | TIMER_CTRL_IE |
 162                              TIMER_CTRL_ONESHOT | TIMER_CTRL_ENABLE;
 163
 164         writel(next, clkevt_base + TIMER_LOAD);
 165         writel(ctrl, clkevt_base + TIMER_CTRL);
 166
 167         return 0;
 168 }
 169
 170 static struct clock_event_device sp804_clockevent = {
 171         .features               = CLOCK_EVT_FEAT_PERIODIC |
 172                                   CLOCK_EVT_FEAT_ONESHOT |
 173                                   CLOCK_EVT_FEAT_DYNIRQ,
 174         .set_state_shutdown     = sp804_shutdown,
 175         .set_state_periodic     = sp804_set_periodic,
 176         .set_state_oneshot      = sp804_shutdown,
 177         .tick_resume            = sp804_shutdown,
 178         .set_next_event         = sp804_set_next_event,
 179         .rating                 = 300,
 180 };
 181
 182 static struct irqaction sp804_timer_irq = {
 183         .name           = "timer",
 184         .flags          = IRQF_TIMER | IRQF_IRQPOLL,
 185         .handler        = sp804_timer_interrupt,
 186         .dev_id         = &sp804_clockevent,
 187 };
 188
 189 void __init __sp804_clockevents_init(void __iomem *base, unsigned int irq, struct clk *clk, const char *name)
 190 {
 191         struct clock_event_device *evt = &sp804_clockevent;
 192         long rate;
 193
 194         if (!clk)
 195                 clk = clk_get_sys("sp804", name);
 196         if (IS_ERR(clk)) {
 197                 pr_err("sp804: %s clock not found: %d\n", name,
 198                         (int)PTR_ERR(clk));
 199                 return;
 200         }
 201
 202         rate = sp804_get_clock_rate(clk);
 203         if (rate < 0)
 204                 return;
 205
 206         clkevt_base = base;
 207         clkevt_reload = DIV_ROUND_CLOSEST(rate, HZ);
 208         evt->name = name;
 209         evt->irq = irq;
 210         evt->cpumask = cpu_possible_mask;
 211
 212         writel(0, base + TIMER_CTRL);
 213
 214         setup_irq(irq, &sp804_timer_irq);
 215         clockevents_config_and_register(evt, rate, 0xf, 0xffffffff);
 216 }
 217
 218 static void __init sp804_of_init(struct device_node *np)
 219 {
 220         static bool initialized = false;
 221         void __iomem *base;
 222         int irq;
 223         u32 irq_num = 0;
 224         struct clk *clk1, *clk2;
 225         const char *name = of_get_property(np, "compatible", NULL);
 226
 227         base = of_iomap(np, 0);
 228         if (WARN_ON(!base))
 229                 return;
 230
 231         /* Ensure timers are disabled */
 232         writel(0, base + TIMER_CTRL);
 233         writel(0, base + TIMER_2_BASE + TIMER_CTRL);
 234
 235         if (initialized || !of_device_is_available(np))
 236                 goto err;
 237
 238         clk1 = of_clk_get(np, 0);
 239         if (IS_ERR(clk1))
 240                 clk1 = NULL;
 241
 242         /* Get the 2nd clock if the timer has 3 timer clocks */
 243         if (of_count_phandle_with_args(np, "clocks", "#clock-cells") == 3) {
 244                 clk2 = of_clk_get(np, 1);
 245                 if (IS_ERR(clk2)) {
 246                         pr_err("sp804: %s clock not found: %d\n", np->name,
 247                                 (int)PTR_ERR(clk2));
 248                         clk2 = NULL;
 249                 }
 250         } else
 251                 clk2 = clk1;
 252
 253         irq = irq_of_parse_and_map(np, 0);
 254         if (irq <= 0)
 255                 goto err;
 256
 257         of_property_read_u32(np, "arm,sp804-has-irq", &irq_num);
 258         if (irq_num == 2) {
 259                 __sp804_clockevents_init(base + TIMER_2_BASE, irq, clk2, name);
 260                 __sp804_clocksource_and_sched_clock_init(base, name, clk1, 1);
 261         } else {
 262                 __sp804_clockevents_init(base, irq, clk1 , name);
 263                 __sp804_clocksource_and_sched_clock_init(base + TIMER_2_BASE,
 264                                                          name, clk2, 1);
 265         }
 266         initialized = true;
 267
 268         return;
 269 err:
 270         iounmap(base);
 271 }
 272 CLOCKSOURCE_OF_DECLARE(sp804, "arm,sp804", sp804_of_init);
 273
 274 static void __init integrator_cp_of_init(struct device_node *np)
 275 {
 276         static int init_count = 0;
 277         void __iomem *base;
 278         int irq;
 279         const char *name = of_get_property(np, "compatible", NULL);
 280         struct clk *clk;
 281
 282         base = of_iomap(np, 0);
 283         if (WARN_ON(!base))
 284                 return;
 285         clk = of_clk_get(np, 0);
 286         if (WARN_ON(IS_ERR(clk)))
 287                 return;
 288
 289         /* Ensure timer is disabled */
 290         writel(0, base + TIMER_CTRL);
 291
 292         if (init_count == 2 || !of_device_is_available(np))
 293                 goto err;
 294
 295         if (!init_count)
 296                 __sp804_clocksource_and_sched_clock_init(base, name, clk, 0);
 297         else {
 298                 irq = irq_of_parse_and_map(np, 0);
 299                 if (irq <= 0)
 300                         goto err;
 301
 302                 __sp804_clockevents_init(base, irq, clk, name);
 303         }
 304
 305         init_count++;
 306         return;
 307 err:
 308         iounmap(base);
 309 }
 310 CLOCKSOURCE_OF_DECLARE(intcp, "arm,integrator-cp-timer", integrator_cp_of_init);