drivers/clocksource/timer-sp804.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  *  linux/drivers/clocksource/timer-sp.c
   4  *
   5  *  Copyright (C) 1999 - 2003 ARM Limited
   6  *  Copyright (C) 2000 Deep Blue Solutions Ltd
   7  */
   8 #include <linux/clk.h>
   9 #include <linux/clocksource.h>
  10 #include <linux/clockchips.h>
  11 #include <linux/err.h>
  12 #include <linux/interrupt.h>
  13 #include <linux/irq.h>
  14 #include <linux/io.h>
  15 #include <linux/of.h>
  16 #include <linux/of_address.h>
  17 #include <linux/of_clk.h>
  18 #include <linux/of_irq.h>
  19 #include <linux/sched_clock.h>
  20
  21 #include <clocksource/timer-sp804.h>
  22
  23 #include "timer-sp.h"
  24
  25 static long __init sp804_get_clock_rate(struct clk *clk)
  26 {
  27         long rate;
  28         int err;
  29
  30         err = clk_prepare(clk);
  31         if (err) {
  32                 pr_err("sp804: clock failed to prepare: %d\n", err);
  33                 clk_put(clk);
  34                 return err;
  35         }
  36
  37         err = clk_enable(clk);
  38         if (err) {
  39                 pr_err("sp804: clock failed to enable: %d\n", err);
  40                 clk_unprepare(clk);
  41                 clk_put(clk);
  42                 return err;
  43         }
  44
  45         rate = clk_get_rate(clk);
  46         if (rate < 0) {
  47                 pr_err("sp804: clock failed to get rate: %ld\n", rate);
  48                 clk_disable(clk);
  49                 clk_unprepare(clk);
  50                 clk_put(clk);
  51         }
  52
  53         return rate;
  54 }
  55
  56 static void __iomem *sched_clock_base;
  57
  58 static u64 notrace sp804_read(void)
  59 {
  60         return ~readl_relaxed(sched_clock_base + TIMER_VALUE);
  61 }
  62
  63 void __init sp804_timer_disable(void __iomem *base)
  64 {
  65         writel(0, base + TIMER_CTRL);
  66 }
  67
  68 int  __init __sp804_clocksource_and_sched_clock_init(void __iomem *base,
  69                                                      const char *name,
  70                                                      struct clk *clk,
  71                                                      int use_sched_clock)
  72 {
  73         long rate;
  74
  75         if (!clk) {
  76                 clk = clk_get_sys("sp804", name);
  77                 if (IS_ERR(clk)) {
  78                         pr_err("sp804: clock not found: %d\n",
  79                                (int)PTR_ERR(clk));
  80                         return PTR_ERR(clk);
  81                 }
  82         }
  83
  84         rate = sp804_get_clock_rate(clk);
  85         if (rate < 0)
  86                 return -EINVAL;
  87
  88         /* setup timer 0 as free-running clocksource */
  89         writel(0, base + TIMER_CTRL);
  90         writel(0xffffffff, base + TIMER_LOAD);
  91         writel(0xffffffff, base + TIMER_VALUE);
  92         writel(TIMER_CTRL_32BIT | TIMER_CTRL_ENABLE | TIMER_CTRL_PERIODIC,
  93                 base + TIMER_CTRL);
  94
  95         clocksource_mmio_init(base + TIMER_VALUE, name,
  96                 rate, 200, 32, clocksource_mmio_readl_down);
  97
  98         if (use_sched_clock) {
  99                 sched_clock_base = base;
 100                 sched_clock_register(sp804_read, 32, rate);
 101         }
 102
 103         return 0;
 104 }
 105
 106
 107 static void __iomem *clkevt_base;
 108 static unsigned long clkevt_reload;
 109
 110 /*
 111  * IRQ handler for the timer
 112  */
 113 static irqreturn_t sp804_timer_interrupt(int irq, void *dev_id)
 114 {
 115         struct clock_event_device *evt = dev_id;
 116
 117         /* clear the interrupt */
 118         writel(1, clkevt_base + TIMER_INTCLR);
 119
 120         evt->event_handler(evt);
 121
 122         return IRQ_HANDLED;
 123 }
 124
 125 static inline void timer_shutdown(struct clock_event_device *evt)
 126 {
 127         writel(0, clkevt_base + TIMER_CTRL);
 128 }
 129
 130 static int sp804_shutdown(struct clock_event_device *evt)
 131 {
 132         timer_shutdown(evt);
 133         return 0;
 134 }
 135
 136 static int sp804_set_periodic(struct clock_event_device *evt)
 137 {
 138         unsigned long ctrl = TIMER_CTRL_32BIT | TIMER_CTRL_IE |
 139                              TIMER_CTRL_PERIODIC | TIMER_CTRL_ENABLE;
 140
 141         timer_shutdown(evt);
 142         writel(clkevt_reload, clkevt_base + TIMER_LOAD);
 143         writel(ctrl, clkevt_base + TIMER_CTRL);
 144         return 0;
 145 }
 146
 147 static int sp804_set_next_event(unsigned long next,
 148         struct clock_event_device *evt)
 149 {
 150         unsigned long ctrl = TIMER_CTRL_32BIT | TIMER_CTRL_IE |
 151                              TIMER_CTRL_ONESHOT | TIMER_CTRL_ENABLE;
 152
 153         writel(next, clkevt_base + TIMER_LOAD);
 154         writel(ctrl, clkevt_base + TIMER_CTRL);
 155
 156         return 0;
 157 }
 158
 159 static struct clock_event_device sp804_clockevent = {
 160         .features               = CLOCK_EVT_FEAT_PERIODIC |
 161                                   CLOCK_EVT_FEAT_ONESHOT |
 162                                   CLOCK_EVT_FEAT_DYNIRQ,
 163         .set_state_shutdown     = sp804_shutdown,
 164         .set_state_periodic     = sp804_set_periodic,
 165         .set_state_oneshot      = sp804_shutdown,
 166         .tick_resume            = sp804_shutdown,
 167         .set_next_event         = sp804_set_next_event,
 168         .rating                 = 300,
 169 };
 170
 171 int __init __sp804_clockevents_init(void __iomem *base, unsigned int irq, struct clk *clk, const char *name)
 172 {
 173         struct clock_event_device *evt = &sp804_clockevent;
 174         long rate;
 175
 176         if (!clk)
 177                 clk = clk_get_sys("sp804", name);
 178         if (IS_ERR(clk)) {
 179                 pr_err("sp804: %s clock not found: %d\n", name,
 180                         (int)PTR_ERR(clk));
 181                 return PTR_ERR(clk);
 182         }
 183
 184         rate = sp804_get_clock_rate(clk);
 185         if (rate < 0)
 186                 return -EINVAL;
 187
 188         clkevt_base = base;
 189         clkevt_reload = DIV_ROUND_CLOSEST(rate, HZ);
 190         evt->name = name;
 191         evt->irq = irq;
 192         evt->cpumask = cpu_possible_mask;
 193
 194         writel(0, base + TIMER_CTRL);
 195
 196         if (request_irq(irq, sp804_timer_interrupt, IRQF_TIMER | IRQF_IRQPOLL,
 197                         "timer", &sp804_clockevent))
 198                 pr_err("%s: request_irq() failed\n", "timer");
 199         clockevents_config_and_register(evt, rate, 0xf, 0xffffffff);
 200
 201         return 0;
 202 }
 203
 204 static int __init sp804_of_init(struct device_node *np)
 205 {
 206         static bool initialized = false;
 207         void __iomem *base;
 208         int irq, ret = -EINVAL;
 209         u32 irq_num = 0;
 210         struct clk *clk1, *clk2;
 211         const char *name = of_get_property(np, "compatible", NULL);
 212
 213         base = of_iomap(np, 0);
 214         if (!base)
 215                 return -ENXIO;
 216
 217         /* Ensure timers are disabled */
 218         writel(0, base + TIMER_CTRL);
 219         writel(0, base + TIMER_2_BASE + TIMER_CTRL);
 220
 221         if (initialized || !of_device_is_available(np)) {
 222                 ret = -EINVAL;
 223                 goto err;
 224         }
 225
 226         clk1 = of_clk_get(np, 0);
 227         if (IS_ERR(clk1))
 228                 clk1 = NULL;
 229
 230         /* Get the 2nd clock if the timer has 3 timer clocks */
 231         if (of_clk_get_parent_count(np) == 3) {
 232                 clk2 = of_clk_get(np, 1);
 233                 if (IS_ERR(clk2)) {
 234                         pr_err("sp804: %pOFn clock not found: %d\n", np,
 235                                 (int)PTR_ERR(clk2));
 236                         clk2 = NULL;
 237                 }
 238         } else
 239                 clk2 = clk1;
 240
 241         irq = irq_of_parse_and_map(np, 0);
 242         if (irq <= 0)
 243                 goto err;
 244
 245         of_property_read_u32(np, "arm,sp804-has-irq", &irq_num);
 246         if (irq_num == 2) {
 247
 248                 ret = __sp804_clockevents_init(base + TIMER_2_BASE, irq, clk2, name);
 249                 if (ret)
 250                         goto err;
 251
 252                 ret = __sp804_clocksource_and_sched_clock_init(base, name, clk1, 1);
 253                 if (ret)
 254                         goto err;
 255         } else {
 256
 257                 ret = __sp804_clockevents_init(base, irq, clk1 , name);
 258                 if (ret)
 259                         goto err;
 260
 261                 ret =__sp804_clocksource_and_sched_clock_init(base + TIMER_2_BASE,
 262                                                               name, clk2, 1);
 263                 if (ret)
 264                         goto err;
 265         }
 266         initialized = true;
 267
 268         return 0;
 269 err:
 270         iounmap(base);
 271         return ret;
 272 }
 273 TIMER_OF_DECLARE(sp804, "arm,sp804", sp804_of_init);
 274
 275 static int __init integrator_cp_of_init(struct device_node *np)
 276 {
 277         static int init_count = 0;
 278         void __iomem *base;
 279         int irq, ret = -EINVAL;
 280         const char *name = of_get_property(np, "compatible", NULL);
 281         struct clk *clk;
 282
 283         base = of_iomap(np, 0);
 284         if (!base) {
 285                 pr_err("Failed to iomap\n");
 286                 return -ENXIO;
 287         }
 288
 289         clk = of_clk_get(np, 0);
 290         if (IS_ERR(clk)) {
 291                 pr_err("Failed to get clock\n");
 292                 return PTR_ERR(clk);
 293         }
 294
 295         /* Ensure timer is disabled */
 296         writel(0, base + TIMER_CTRL);
 297
 298         if (init_count == 2 || !of_device_is_available(np))
 299                 goto err;
 300
 301         if (!init_count) {
 302                 ret = __sp804_clocksource_and_sched_clock_init(base, name, clk, 0);
 303                 if (ret)
 304                         goto err;
 305         } else {
 306                 irq = irq_of_parse_and_map(np, 0);
 307                 if (irq <= 0)
 308                         goto err;
 309
 310                 ret = __sp804_clockevents_init(base, irq, clk, name);
 311                 if (ret)
 312                         goto err;
 313         }
 314
 315         init_count++;
 316         return 0;
 317 err:
 318         iounmap(base);
 319         return ret;
 320 }
 321 TIMER_OF_DECLARE(intcp, "arm,integrator-cp-timer", integrator_cp_of_init);