drivers/clocksource/time-armada-370-xp.c

   1 /*
   2  * Marvell Armada 370/XP SoC timer handling.
   3  *
   4  * Copyright (C) 2012 Marvell
   5  *
   6  * Lior Amsalem <alior@marvell.com>
   7  * Gregory CLEMENT <gregory.clement@free-electrons.com>
   8  * Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
   9  *
  10  * This file is licensed under the terms of the GNU General Public
  11  * License version 2.  This program is licensed "as is" without any
  12  * warranty of any kind, whether express or implied.
  13  *
  14  * Timer 0 is used as free-running clocksource, while timer 1 is
  15  * used as clock_event_device.
  16  */
  17
  18 #include <linux/init.h>
  19 #include <linux/platform_device.h>
  20 #include <linux/kernel.h>
  21 #include <linux/clk.h>
  22 #include <linux/timer.h>
  23 #include <linux/clockchips.h>
  24 #include <linux/interrupt.h>
  25 #include <linux/of.h>
  26 #include <linux/of_irq.h>
  27 #include <linux/of_address.h>
  28 #include <linux/irq.h>
  29 #include <linux/module.h>
  30
  31 #include <asm/sched_clock.h>
  32 #include <asm/localtimer.h>
  33 #include <linux/percpu.h>
  34 /*
  35  * Timer block registers.
  36  */
  37 #define TIMER_CTRL_OFF          0x0000
  38 #define  TIMER0_EN               0x0001
  39 #define  TIMER0_RELOAD_EN        0x0002
  40 #define  TIMER0_25MHZ            0x0800
  41 #define  TIMER0_DIV(div)         ((div) << 19)
  42 #define  TIMER1_EN               0x0004
  43 #define  TIMER1_RELOAD_EN        0x0008
  44 #define  TIMER1_25MHZ            0x1000
  45 #define  TIMER1_DIV(div)         ((div) << 22)
  46 #define TIMER_EVENTS_STATUS     0x0004
  47 #define  TIMER0_CLR_MASK         (~0x1)
  48 #define  TIMER1_CLR_MASK         (~0x100)
  49 #define TIMER0_RELOAD_OFF       0x0010
  50 #define TIMER0_VAL_OFF          0x0014
  51 #define TIMER1_RELOAD_OFF       0x0018
  52 #define TIMER1_VAL_OFF          0x001c
  53
  54 #define LCL_TIMER_EVENTS_STATUS 0x0028
  55 /* Global timers are connected to the coherency fabric clock, and the
  56    below divider reduces their incrementing frequency. */
  57 #define TIMER_DIVIDER_SHIFT     5
  58 #define TIMER_DIVIDER           (1 << TIMER_DIVIDER_SHIFT)
  59
  60 /*
  61  * SoC-specific data.
  62  */
  63 static void __iomem *timer_base, *local_base;
  64 static unsigned int timer_clk;
  65 static bool timer25Mhz = true;
  66
  67 /*
  68  * Number of timer ticks per jiffy.
  69  */
  70 static u32 ticks_per_jiffy;
  71
  72 static struct clock_event_device __percpu **percpu_armada_370_xp_evt;
  73
  74 static u32 notrace armada_370_xp_read_sched_clock(void)
  75 {
  76         return ~readl(timer_base + TIMER0_VAL_OFF);
  77 }
  78
  79 /*
  80  * Clockevent handling.
  81  */
  82 static int
  83 armada_370_xp_clkevt_next_event(unsigned long delta,
  84                                 struct clock_event_device *dev)
  85 {
  86         u32 u;
  87         /*
  88          * Clear clockevent timer interrupt.
  89          */
  90         writel(TIMER0_CLR_MASK, local_base + LCL_TIMER_EVENTS_STATUS);
  91
  92         /*
  93          * Setup new clockevent timer value.
  94          */
  95         writel(delta, local_base + TIMER0_VAL_OFF);
  96
  97         /*
  98          * Enable the timer.
  99          */
 100         u = readl(local_base + TIMER_CTRL_OFF);
 101         u = ((u & ~TIMER0_RELOAD_EN) | TIMER0_EN |
 102              TIMER0_DIV(TIMER_DIVIDER_SHIFT));
 103         writel(u, local_base + TIMER_CTRL_OFF);
 104
 105         return 0;
 106 }
 107
 108 static void
 109 armada_370_xp_clkevt_mode(enum clock_event_mode mode,
 110                           struct clock_event_device *dev)
 111 {
 112         u32 u;
 113
 114         if (mode == CLOCK_EVT_MODE_PERIODIC) {
 115
 116                 /*
 117                  * Setup timer to fire at 1/HZ intervals.
 118                  */
 119                 writel(ticks_per_jiffy - 1, local_base + TIMER0_RELOAD_OFF);
 120                 writel(ticks_per_jiffy - 1, local_base + TIMER0_VAL_OFF);
 121
 122                 /*
 123                  * Enable timer.
 124                  */
 125
 126                 u = readl(local_base + TIMER_CTRL_OFF);
 127
 128                 writel((u | TIMER0_EN | TIMER0_RELOAD_EN |
 129                         TIMER0_DIV(TIMER_DIVIDER_SHIFT)),
 130                         local_base + TIMER_CTRL_OFF);
 131         } else {
 132                 /*
 133                  * Disable timer.
 134                  */
 135                 u = readl(local_base + TIMER_CTRL_OFF);
 136                 writel(u & ~TIMER0_EN, local_base + TIMER_CTRL_OFF);
 137
 138                 /*
 139                  * ACK pending timer interrupt.
 140                  */
 141                 writel(TIMER0_CLR_MASK, local_base + LCL_TIMER_EVENTS_STATUS);
 142         }
 143 }
 144
 145 static struct clock_event_device armada_370_xp_clkevt = {
 146         .name           = "armada_370_xp_per_cpu_tick",
 147         .features       = CLOCK_EVT_FEAT_ONESHOT | CLOCK_EVT_FEAT_PERIODIC,
 148         .shift          = 32,
 149         .rating         = 300,
 150         .set_next_event = armada_370_xp_clkevt_next_event,
 151         .set_mode       = armada_370_xp_clkevt_mode,
 152 };
 153
 154 static irqreturn_t armada_370_xp_timer_interrupt(int irq, void *dev_id)
 155 {
 156         /*
 157          * ACK timer interrupt and call event handler.
 158          */
 159         struct clock_event_device *evt = *(struct clock_event_device **)dev_id;
 160
 161         writel(TIMER0_CLR_MASK, local_base + LCL_TIMER_EVENTS_STATUS);
 162         evt->event_handler(evt);
 163
 164         return IRQ_HANDLED;
 165 }
 166
 167 /*
 168  * Setup the local clock events for a CPU.
 169  */
 170 static int __cpuinit armada_370_xp_timer_setup(struct clock_event_device *evt)
 171 {
 172         u32 u;
 173         int cpu = smp_processor_id();
 174
 175         /* Use existing clock_event for cpu 0 */
 176         if (!smp_processor_id())
 177                 return 0;
 178
 179         u = readl(local_base + TIMER_CTRL_OFF);
 180         if (timer25Mhz)
 181                 writel(u | TIMER0_25MHZ, local_base + TIMER_CTRL_OFF);
 182         else
 183                 writel(u & ~TIMER0_25MHZ, local_base + TIMER_CTRL_OFF);
 184
 185         evt->name               = armada_370_xp_clkevt.name;
 186         evt->irq                = armada_370_xp_clkevt.irq;
 187         evt->features           = armada_370_xp_clkevt.features;
 188         evt->shift              = armada_370_xp_clkevt.shift;
 189         evt->rating             = armada_370_xp_clkevt.rating,
 190         evt->set_next_event     = armada_370_xp_clkevt_next_event,
 191         evt->set_mode           = armada_370_xp_clkevt_mode,
 192         evt->cpumask            = cpumask_of(cpu);
 193
 194         *__this_cpu_ptr(percpu_armada_370_xp_evt) = evt;
 195
 196         clockevents_config_and_register(evt, timer_clk, 1, 0xfffffffe);
 197         enable_percpu_irq(evt->irq, 0);
 198
 199         return 0;
 200 }
 201
 202 static void  armada_370_xp_timer_stop(struct clock_event_device *evt)
 203 {
 204         evt->set_mode(CLOCK_EVT_MODE_UNUSED, evt);
 205         disable_percpu_irq(evt->irq);
 206 }
 207
 208 static struct local_timer_ops armada_370_xp_local_timer_ops __cpuinitdata = {
 209         .setup  = armada_370_xp_timer_setup,
 210         .stop   =  armada_370_xp_timer_stop,
 211 };
 212
 213 void __init armada_370_xp_timer_init(void)
 214 {
 215         u32 u;
 216         struct device_node *np;
 217         int res;
 218
 219         np = of_find_compatible_node(NULL, NULL, "marvell,armada-370-xp-timer");
 220         timer_base = of_iomap(np, 0);
 221         WARN_ON(!timer_base);
 222         local_base = of_iomap(np, 1);
 223
 224         if (of_find_property(np, "marvell,timer-25Mhz", NULL)) {
 225                 /* The fixed 25MHz timer is available so let's use it */
 226                 u = readl(local_base + TIMER_CTRL_OFF);
 227                 writel(u | TIMER0_25MHZ,
 228                        local_base + TIMER_CTRL_OFF);
 229                 u = readl(timer_base + TIMER_CTRL_OFF);
 230                 writel(u | TIMER0_25MHZ,
 231                        timer_base + TIMER_CTRL_OFF);
 232                 timer_clk = 25000000;
 233         } else {
 234                 unsigned long rate = 0;
 235                 struct clk *clk = of_clk_get(np, 0);
 236                 WARN_ON(IS_ERR(clk));
 237                 rate =  clk_get_rate(clk);
 238                 u = readl(local_base + TIMER_CTRL_OFF);
 239                 writel(u & ~(TIMER0_25MHZ),
 240                        local_base + TIMER_CTRL_OFF);
 241
 242                 u = readl(timer_base + TIMER_CTRL_OFF);
 243                 writel(u & ~(TIMER0_25MHZ),
 244                        timer_base + TIMER_CTRL_OFF);
 245
 246                 timer_clk = rate / TIMER_DIVIDER;
 247                 timer25Mhz = false;
 248         }
 249
 250         /*
 251          * We use timer 0 as clocksource, and private(local) timer 0
 252          * for clockevents
 253          */
 254         armada_370_xp_clkevt.irq = irq_of_parse_and_map(np, 4);
 255
 256         ticks_per_jiffy = (timer_clk + HZ / 2) / HZ;
 257
 258         /*
 259          * Set scale and timer for sched_clock.
 260          */
 261         setup_sched_clock(armada_370_xp_read_sched_clock, 32, timer_clk);
 262
 263         /*
 264          * Setup free-running clocksource timer (interrupts
 265          * disabled).
 266          */
 267         writel(0xffffffff, timer_base + TIMER0_VAL_OFF);
 268         writel(0xffffffff, timer_base + TIMER0_RELOAD_OFF);
 269
 270         u = readl(timer_base + TIMER_CTRL_OFF);
 271
 272         writel((u | TIMER0_EN | TIMER0_RELOAD_EN |
 273                 TIMER0_DIV(TIMER_DIVIDER_SHIFT)), timer_base + TIMER_CTRL_OFF);
 274
 275         clocksource_mmio_init(timer_base + TIMER0_VAL_OFF,
 276                               "armada_370_xp_clocksource",
 277                               timer_clk, 300, 32, clocksource_mmio_readl_down);
 278
 279         /* Register the clockevent on the private timer of CPU 0 */
 280         armada_370_xp_clkevt.cpumask = cpumask_of(0);
 281         clockevents_config_and_register(&armada_370_xp_clkevt,
 282                                         timer_clk, 1, 0xfffffffe);
 283
 284         percpu_armada_370_xp_evt = alloc_percpu(struct clock_event_device *);
 285
 286
 287         /*
 288          * Setup clockevent timer (interrupt-driven).
 289          */
 290         *__this_cpu_ptr(percpu_armada_370_xp_evt) = &armada_370_xp_clkevt;
 291         res = request_percpu_irq(armada_370_xp_clkevt.irq,
 292                                 armada_370_xp_timer_interrupt,
 293                                 armada_370_xp_clkevt.name,
 294                                 percpu_armada_370_xp_evt);
 295         if (!res) {
 296                 enable_percpu_irq(armada_370_xp_clkevt.irq, 0);
 297 #ifdef CONFIG_LOCAL_TIMERS
 298                 local_timer_register(&armada_370_xp_local_timer_ops);
 299 #endif
 300         }
 301 }