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
  32 #include <asm/sched_clock.h>
  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 u32 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                 setup_sched_clock(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         .set_mode       = sp804_set_mode,
 171         .set_next_event = sp804_set_next_event,
 172         .rating         = 300,
 173 };
 174
 175 static struct irqaction sp804_timer_irq = {
 176         .name           = "timer",
 177         .flags          = IRQF_DISABLED | IRQF_TIMER | IRQF_IRQPOLL,
 178         .handler        = sp804_timer_interrupt,
 179         .dev_id         = &sp804_clockevent,
 180 };
 181
 182 void __init __sp804_clockevents_init(void __iomem *base, unsigned int irq, struct clk *clk, const char *name)
 183 {
 184         struct clock_event_device *evt = &sp804_clockevent;
 185         long rate;
 186
 187         if (!clk)
 188                 clk = clk_get_sys("sp804", name);
 189         if (IS_ERR(clk)) {
 190                 pr_err("sp804: %s clock not found: %d\n", name,
 191                         (int)PTR_ERR(clk));
 192                 return;
 193         }
 194
 195         rate = sp804_get_clock_rate(clk);
 196         if (rate < 0)
 197                 return;
 198
 199         clkevt_base = base;
 200         clkevt_reload = DIV_ROUND_CLOSEST(rate, HZ);
 201         evt->name = name;
 202         evt->irq = irq;
 203         evt->cpumask = cpu_possible_mask;
 204
 205         writel(0, base + TIMER_CTRL);
 206
 207         setup_irq(irq, &sp804_timer_irq);
 208         clockevents_config_and_register(evt, rate, 0xf, 0xffffffff);
 209 }
 210
 211 static void __init sp804_of_init(struct device_node *np)
 212 {
 213         static bool initialized = false;
 214         void __iomem *base;
 215         int irq;
 216         u32 irq_num = 0;
 217         struct clk *clk1, *clk2;
 218         const char *name = of_get_property(np, "compatible", NULL);
 219
 220         base = of_iomap(np, 0);
 221         if (WARN_ON(!base))
 222                 return;
 223
 224         /* Ensure timers are disabled */
 225         writel(0, base + TIMER_CTRL);
 226         writel(0, base + TIMER_2_BASE + TIMER_CTRL);
 227
 228         if (initialized || !of_device_is_available(np))
 229                 goto err;
 230
 231         clk1 = of_clk_get(np, 0);
 232         if (IS_ERR(clk1))
 233                 clk1 = NULL;
 234
 235         /* Get the 2nd clock if the timer has 2 timer clocks */
 236         if (of_count_phandle_with_args(np, "clocks", "#clock-cells") == 3) {
 237                 clk2 = of_clk_get(np, 1);
 238                 if (IS_ERR(clk2)) {
 239                         pr_err("sp804: %s clock not found: %d\n", np->name,
 240                                 (int)PTR_ERR(clk2));
 241                         goto err;
 242                 }
 243         } else
 244                 clk2 = clk1;
 245
 246         irq = irq_of_parse_and_map(np, 0);
 247         if (irq <= 0)
 248                 goto err;
 249
 250         of_property_read_u32(np, "arm,sp804-has-irq", &irq_num);
 251         if (irq_num == 2) {
 252                 __sp804_clockevents_init(base + TIMER_2_BASE, irq, clk2, name);
 253                 __sp804_clocksource_and_sched_clock_init(base, name, clk1, 1);
 254         } else {
 255                 __sp804_clockevents_init(base, irq, clk1 , name);
 256                 __sp804_clocksource_and_sched_clock_init(base + TIMER_2_BASE,
 257                                                          name, clk2, 1);
 258         }
 259         initialized = true;
 260
 261         return;
 262 err:
 263         iounmap(base);
 264 }
 265 CLOCKSOURCE_OF_DECLARE(sp804, "arm,sp804", sp804_of_init);
 266
 267 static void __init integrator_cp_of_init(struct device_node *np)
 268 {
 269         static int init_count = 0;
 270         void __iomem *base;
 271         int irq;
 272         const char *name = of_get_property(np, "compatible", NULL);
 273
 274         base = of_iomap(np, 0);
 275         if (WARN_ON(!base))
 276                 return;
 277
 278         /* Ensure timer is disabled */
 279         writel(0, base + TIMER_CTRL);
 280
 281         if (init_count == 2 || !of_device_is_available(np))
 282                 goto err;
 283
 284         if (!init_count)
 285                 sp804_clocksource_init(base, name);
 286         else {
 287                 irq = irq_of_parse_and_map(np, 0);
 288                 if (irq <= 0)
 289                         goto err;
 290
 291                 sp804_clockevents_init(base, irq, name);
 292         }
 293
 294         init_count++;
 295         return;
 296 err:
 297         iounmap(base);
 298 }
 299 CLOCKSOURCE_OF_DECLARE(intcp, "arm,integrator-cp-timer", integrator_cp_of_init);