arch/arm/common/timer-sp.c

   1 /*
   2  *  linux/arch/arm/common/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 <asm/hardware/arm_timer.h>
  34 #include <asm/hardware/timer-sp.h>
  35
  36 static long __init sp804_get_clock_rate(struct clk *clk)
  37 {
  38         long rate;
  39         int err;
  40
  41         err = clk_prepare(clk);
  42         if (err) {
  43                 pr_err("sp804: clock failed to prepare: %d\n", err);
  44                 clk_put(clk);
  45                 return err;
  46         }
  47
  48         err = clk_enable(clk);
  49         if (err) {
  50                 pr_err("sp804: clock failed to enable: %d\n", err);
  51                 clk_unprepare(clk);
  52                 clk_put(clk);
  53                 return err;
  54         }
  55
  56         rate = clk_get_rate(clk);
  57         if (rate < 0) {
  58                 pr_err("sp804: clock failed to get rate: %ld\n", rate);
  59                 clk_disable(clk);
  60                 clk_unprepare(clk);
  61                 clk_put(clk);
  62         }
  63
  64         return rate;
  65 }
  66
  67 static void __iomem *sched_clock_base;
  68
  69 static u64 notrace sp804_read(void)
  70 {
  71         return ~readl_relaxed(sched_clock_base + TIMER_VALUE);
  72 }
  73
  74 void __init __sp804_clocksource_and_sched_clock_init(void __iomem *base,
  75                                                      const char *name,
  76                                                      struct clk *clk,
  77                                                      int use_sched_clock)
  78 {
  79         long rate;
  80
  81         if (!clk) {
  82                 clk = clk_get_sys("sp804", name);
  83                 if (IS_ERR(clk)) {
  84                         pr_err("sp804: clock not found: %d\n",
  85                                (int)PTR_ERR(clk));
  86                         return;
  87                 }
  88         }
  89
  90         rate = sp804_get_clock_rate(clk);
  91
  92         if (rate < 0)
  93                 return;
  94
  95         /* setup timer 0 as free-running clocksource */
  96         writel(0, base + TIMER_CTRL);
  97         writel(0xffffffff, base + TIMER_LOAD);
  98         writel(0xffffffff, base + TIMER_VALUE);
  99         writel(TIMER_CTRL_32BIT | TIMER_CTRL_ENABLE | TIMER_CTRL_PERIODIC,
 100                 base + TIMER_CTRL);
 101
 102         clocksource_mmio_init(base + TIMER_VALUE, name,
 103                 rate, 200, 32, clocksource_mmio_readl_down);
 104
 105         if (use_sched_clock) {
 106                 sched_clock_base = base;
 107                 sched_clock_register(sp804_read, 32, rate);
 108         }
 109 }
 110
 111
 112 static void __iomem *clkevt_base;
 113 static unsigned long clkevt_reload;
 114
 115 /*
 116  * IRQ handler for the timer
 117  */
 118 static irqreturn_t sp804_timer_interrupt(int irq, void *dev_id)
 119 {
 120         struct clock_event_device *evt = dev_id;
 121
 122         /* clear the interrupt */
 123         writel(1, clkevt_base + TIMER_INTCLR);
 124
 125         evt->event_handler(evt);
 126
 127         return IRQ_HANDLED;
 128 }
 129
 130 static void sp804_set_mode(enum clock_event_mode mode,
 131         struct clock_event_device *evt)
 132 {
 133         unsigned long ctrl = TIMER_CTRL_32BIT | TIMER_CTRL_IE;
 134
 135         writel(ctrl, clkevt_base + TIMER_CTRL);
 136
 137         switch (mode) {
 138         case CLOCK_EVT_MODE_PERIODIC:
 139                 writel(clkevt_reload, clkevt_base + TIMER_LOAD);
 140                 ctrl |= TIMER_CTRL_PERIODIC | TIMER_CTRL_ENABLE;
 141                 break;
 142
 143         case CLOCK_EVT_MODE_ONESHOT:
 144                 /* period set, and timer enabled in 'next_event' hook */
 145                 ctrl |= TIMER_CTRL_ONESHOT;
 146                 break;
 147
 148         case CLOCK_EVT_MODE_UNUSED:
 149         case CLOCK_EVT_MODE_SHUTDOWN:
 150         default:
 151                 break;
 152         }
 153
 154         writel(ctrl, clkevt_base + TIMER_CTRL);
 155 }
 156
 157 static int sp804_set_next_event(unsigned long next,
 158         struct clock_event_device *evt)
 159 {
 160         unsigned long ctrl = readl(clkevt_base + TIMER_CTRL);
 161
 162         writel(next, clkevt_base + TIMER_LOAD);
 163         writel(ctrl | TIMER_CTRL_ENABLE, clkevt_base + TIMER_CTRL);
 164
 165         return 0;
 166 }
 167
 168 static struct clock_event_device sp804_clockevent = {
 169         .features       = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT |
 170                 CLOCK_EVT_FEAT_DYNIRQ,
 171         .set_mode       = sp804_set_mode,
 172         .set_next_event = sp804_set_next_event,
 173         .rating         = 300,
 174 };
 175
 176 static struct irqaction sp804_timer_irq = {
 177         .name           = "timer",
 178         .flags          = IRQF_TIMER | IRQF_IRQPOLL,
 179         .handler        = sp804_timer_interrupt,
 180         .dev_id         = &sp804_clockevent,
 181 };
 182
 183 void __init __sp804_clockevents_init(void __iomem *base, unsigned int irq, struct clk *clk, const char *name)
 184 {
 185         struct clock_event_device *evt = &sp804_clockevent;
 186         long rate;
 187
 188         if (!clk)
 189                 clk = clk_get_sys("sp804", name);
 190         if (IS_ERR(clk)) {
 191                 pr_err("sp804: %s clock not found: %d\n", name,
 192                         (int)PTR_ERR(clk));
 193                 return;
 194         }
 195
 196         rate = sp804_get_clock_rate(clk);
 197         if (rate < 0)
 198                 return;
 199
 200         clkevt_base = base;
 201         clkevt_reload = DIV_ROUND_CLOSEST(rate, HZ);
 202         evt->name = name;
 203         evt->irq = irq;
 204         evt->cpumask = cpu_possible_mask;
 205
 206         writel(0, base + TIMER_CTRL);
 207
 208         setup_irq(irq, &sp804_timer_irq);
 209         clockevents_config_and_register(evt, rate, 0xf, 0xffffffff);
 210 }
 211
 212 static void __init sp804_of_init(struct device_node *np)
 213 {
 214         static bool initialized = false;
 215         void __iomem *base;
 216         int irq;
 217         u32 irq_num = 0;
 218         struct clk *clk1, *clk2;
 219         const char *name = of_get_property(np, "compatible", NULL);
 220
 221         base = of_iomap(np, 0);
 222         if (WARN_ON(!base))
 223                 return;
 224
 225         /* Ensure timers are disabled */
 226         writel(0, base + TIMER_CTRL);
 227         writel(0, base + TIMER_2_BASE + TIMER_CTRL);
 228
 229         if (initialized || !of_device_is_available(np))
 230                 goto err;
 231
 232         clk1 = of_clk_get(np, 0);
 233         if (IS_ERR(clk1))
 234                 clk1 = NULL;
 235
 236         /* Get the 2nd clock if the timer has 2 timer clocks */
 237         if (of_count_phandle_with_args(np, "clocks", "#clock-cells") == 3) {
 238                 clk2 = of_clk_get(np, 1);
 239                 if (IS_ERR(clk2)) {
 240                         pr_err("sp804: %s clock not found: %d\n", np->name,
 241                                 (int)PTR_ERR(clk2));
 242                         goto err;
 243                 }
 244         } else
 245                 clk2 = clk1;
 246
 247         irq = irq_of_parse_and_map(np, 0);
 248         if (irq <= 0)
 249                 goto err;
 250
 251         of_property_read_u32(np, "arm,sp804-has-irq", &irq_num);
 252         if (irq_num == 2) {
 253                 __sp804_clockevents_init(base + TIMER_2_BASE, irq, clk2, name);
 254                 __sp804_clocksource_and_sched_clock_init(base, name, clk1, 1);
 255         } else {
 256                 __sp804_clockevents_init(base, irq, clk1 , name);
 257                 __sp804_clocksource_and_sched_clock_init(base + TIMER_2_BASE,
 258                                                          name, clk2, 1);
 259         }
 260         initialized = true;
 261
 262         return;
 263 err:
 264         iounmap(base);
 265 }
 266 CLOCKSOURCE_OF_DECLARE(sp804, "arm,sp804", sp804_of_init);
 267
 268 static void __init integrator_cp_of_init(struct device_node *np)
 269 {
 270         static int init_count = 0;
 271         void __iomem *base;
 272         int irq;
 273         const char *name = of_get_property(np, "compatible", NULL);
 274         struct clk *clk;
 275
 276         base = of_iomap(np, 0);
 277         if (WARN_ON(!base))
 278                 return;
 279         clk = of_clk_get(np, 0);
 280         if (WARN_ON(IS_ERR(clk)))
 281                 return;
 282
 283         /* Ensure timer is disabled */
 284         writel(0, base + TIMER_CTRL);
 285
 286         if (init_count == 2 || !of_device_is_available(np))
 287                 goto err;
 288
 289         if (!init_count)
 290                 __sp804_clocksource_and_sched_clock_init(base, name, clk, 0);
 291         else {
 292                 irq = irq_of_parse_and_map(np, 0);
 293                 if (irq <= 0)
 294                         goto err;
 295
 296                 __sp804_clockevents_init(base, irq, clk, name);
 297         }
 298
 299         init_count++;
 300         return;
 301 err:
 302         iounmap(base);
 303 }
 304 CLOCKSOURCE_OF_DECLARE(intcp, "arm,integrator-cp-timer", integrator_cp_of_init);