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 int  __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 PTR_ERR(clk);
  93                 }
  94         }
  95
  96         rate = sp804_get_clock_rate(clk);
  97         if (rate < 0)
  98                 return -EINVAL;
  99
 100         /* setup timer 0 as free-running clocksource */
 101         writel(0, base + TIMER_CTRL);
 102         writel(0xffffffff, base + TIMER_LOAD);
 103         writel(0xffffffff, base + TIMER_VALUE);
 104         writel(TIMER_CTRL_32BIT | TIMER_CTRL_ENABLE | TIMER_CTRL_PERIODIC,
 105                 base + TIMER_CTRL);
 106
 107         clocksource_mmio_init(base + TIMER_VALUE, name,
 108                 rate, 200, 32, clocksource_mmio_readl_down);
 109
 110         if (use_sched_clock) {
 111                 sched_clock_base = base;
 112                 sched_clock_register(sp804_read, 32, rate);
 113         }
 114
 115         return 0;
 116 }
 117
 118
 119 static void __iomem *clkevt_base;
 120 static unsigned long clkevt_reload;
 121
 122 /*
 123  * IRQ handler for the timer
 124  */
 125 static irqreturn_t sp804_timer_interrupt(int irq, void *dev_id)
 126 {
 127         struct clock_event_device *evt = dev_id;
 128
 129         /* clear the interrupt */
 130         writel(1, clkevt_base + TIMER_INTCLR);
 131
 132         evt->event_handler(evt);
 133
 134         return IRQ_HANDLED;
 135 }
 136
 137 static inline void timer_shutdown(struct clock_event_device *evt)
 138 {
 139         writel(0, clkevt_base + TIMER_CTRL);
 140 }
 141
 142 static int sp804_shutdown(struct clock_event_device *evt)
 143 {
 144         timer_shutdown(evt);
 145         return 0;
 146 }
 147
 148 static int sp804_set_periodic(struct clock_event_device *evt)
 149 {
 150         unsigned long ctrl = TIMER_CTRL_32BIT | TIMER_CTRL_IE |
 151                              TIMER_CTRL_PERIODIC | TIMER_CTRL_ENABLE;
 152
 153         timer_shutdown(evt);
 154         writel(clkevt_reload, clkevt_base + TIMER_LOAD);
 155         writel(ctrl, clkevt_base + TIMER_CTRL);
 156         return 0;
 157 }
 158
 159 static int sp804_set_next_event(unsigned long next,
 160         struct clock_event_device *evt)
 161 {
 162         unsigned long ctrl = TIMER_CTRL_32BIT | TIMER_CTRL_IE |
 163                              TIMER_CTRL_ONESHOT | TIMER_CTRL_ENABLE;
 164
 165         writel(next, clkevt_base + TIMER_LOAD);
 166         writel(ctrl, clkevt_base + TIMER_CTRL);
 167
 168         return 0;
 169 }
 170
 171 static struct clock_event_device sp804_clockevent = {
 172         .features               = CLOCK_EVT_FEAT_PERIODIC |
 173                                   CLOCK_EVT_FEAT_ONESHOT |
 174                                   CLOCK_EVT_FEAT_DYNIRQ,
 175         .set_state_shutdown     = sp804_shutdown,
 176         .set_state_periodic     = sp804_set_periodic,
 177         .set_state_oneshot      = sp804_shutdown,
 178         .tick_resume            = sp804_shutdown,
 179         .set_next_event         = sp804_set_next_event,
 180         .rating                 = 300,
 181 };
 182
 183 static struct irqaction sp804_timer_irq = {
 184         .name           = "timer",
 185         .flags          = IRQF_TIMER | IRQF_IRQPOLL,
 186         .handler        = sp804_timer_interrupt,
 187         .dev_id         = &sp804_clockevent,
 188 };
 189
 190 int __init __sp804_clockevents_init(void __iomem *base, unsigned int irq, struct clk *clk, const char *name)
 191 {
 192         struct clock_event_device *evt = &sp804_clockevent;
 193         long rate;
 194
 195         if (!clk)
 196                 clk = clk_get_sys("sp804", name);
 197         if (IS_ERR(clk)) {
 198                 pr_err("sp804: %s clock not found: %d\n", name,
 199                         (int)PTR_ERR(clk));
 200                 return PTR_ERR(clk);
 201         }
 202
 203         rate = sp804_get_clock_rate(clk);
 204         if (rate < 0)
 205                 return -EINVAL;
 206
 207         clkevt_base = base;
 208         clkevt_reload = DIV_ROUND_CLOSEST(rate, HZ);
 209         evt->name = name;
 210         evt->irq = irq;
 211         evt->cpumask = cpu_possible_mask;
 212
 213         writel(0, base + TIMER_CTRL);
 214
 215         setup_irq(irq, &sp804_timer_irq);
 216         clockevents_config_and_register(evt, rate, 0xf, 0xffffffff);
 217
 218         return 0;
 219 }
 220
 221 static int __init sp804_of_init(struct device_node *np)
 222 {
 223         static bool initialized = false;
 224         void __iomem *base;
 225         int irq, ret = -EINVAL;
 226         u32 irq_num = 0;
 227         struct clk *clk1, *clk2;
 228         const char *name = of_get_property(np, "compatible", NULL);
 229
 230         base = of_iomap(np, 0);
 231         if (!base)
 232                 return -ENXIO;
 233
 234         /* Ensure timers are disabled */
 235         writel(0, base + TIMER_CTRL);
 236         writel(0, base + TIMER_2_BASE + TIMER_CTRL);
 237
 238         if (initialized || !of_device_is_available(np)) {
 239                 ret = -EINVAL;
 240                 goto err;
 241         }
 242
 243         clk1 = of_clk_get(np, 0);
 244         if (IS_ERR(clk1))
 245                 clk1 = NULL;
 246
 247         /* Get the 2nd clock if the timer has 3 timer clocks */
 248         if (of_count_phandle_with_args(np, "clocks", "#clock-cells") == 3) {
 249                 clk2 = of_clk_get(np, 1);
 250                 if (IS_ERR(clk2)) {
 251                         pr_err("sp804: %s clock not found: %d\n", np->name,
 252                                 (int)PTR_ERR(clk2));
 253                         clk2 = NULL;
 254                 }
 255         } else
 256                 clk2 = clk1;
 257
 258         irq = irq_of_parse_and_map(np, 0);
 259         if (irq <= 0)
 260                 goto err;
 261
 262         of_property_read_u32(np, "arm,sp804-has-irq", &irq_num);
 263         if (irq_num == 2) {
 264
 265                 ret = __sp804_clockevents_init(base + TIMER_2_BASE, irq, clk2, name);
 266                 if (ret)
 267                         goto err;
 268
 269                 ret = __sp804_clocksource_and_sched_clock_init(base, name, clk1, 1);
 270                 if (ret)
 271                         goto err;
 272         } else {
 273
 274                 ret = __sp804_clockevents_init(base, irq, clk1 , name);
 275                 if (ret)
 276                         goto err;
 277
 278                 ret =__sp804_clocksource_and_sched_clock_init(base + TIMER_2_BASE,
 279                                                               name, clk2, 1);
 280                 if (ret)
 281                         goto err;
 282         }
 283         initialized = true;
 284
 285         return 0;
 286 err:
 287         iounmap(base);
 288         return ret;
 289 }
 290 CLOCKSOURCE_OF_DECLARE(sp804, "arm,sp804", sp804_of_init);
 291
 292 static int __init integrator_cp_of_init(struct device_node *np)
 293 {
 294         static int init_count = 0;
 295         void __iomem *base;
 296         int irq, ret = -EINVAL;
 297         const char *name = of_get_property(np, "compatible", NULL);
 298         struct clk *clk;
 299
 300         base = of_iomap(np, 0);
 301         if (!base) {
 302                 pr_err("Failed to iomap");
 303                 return -ENXIO;
 304         }
 305
 306         clk = of_clk_get(np, 0);
 307         if (IS_ERR(clk)) {
 308                 pr_err("Failed to get clock");
 309                 return PTR_ERR(clk);
 310         }
 311
 312         /* Ensure timer is disabled */
 313         writel(0, base + TIMER_CTRL);
 314
 315         if (init_count == 2 || !of_device_is_available(np))
 316                 goto err;
 317
 318         if (!init_count) {
 319                 ret = __sp804_clocksource_and_sched_clock_init(base, name, clk, 0);
 320                 if (ret)
 321                         goto err;
 322         } else {
 323                 irq = irq_of_parse_and_map(np, 0);
 324                 if (irq <= 0)
 325                         goto err;
 326
 327                 ret = __sp804_clockevents_init(base, irq, clk, name);
 328                 if (ret)
 329                         goto err;
 330         }
 331
 332         init_count++;
 333         return 0;
 334 err:
 335         iounmap(base);
 336         return ret;
 337 }
 338 CLOCKSOURCE_OF_DECLARE(intcp, "arm,integrator-cp-timer", integrator_cp_of_init);