arch/microblaze/kernel/timer.c

   1 /*
   2  * Copyright (C) 2007-2013 Michal Simek <monstr@monstr.eu>
   3  * Copyright (C) 2012-2013 Xilinx, Inc.
   4  * Copyright (C) 2007-2009 PetaLogix
   5  * Copyright (C) 2006 Atmark Techno, Inc.
   6  *
   7  * This file is subject to the terms and conditions of the GNU General Public
   8  * License. See the file "COPYING" in the main directory of this archive
   9  * for more details.
  10  */
  11
  12 #include <linux/interrupt.h>
  13 #include <linux/delay.h>
  14 #include <linux/sched.h>
  15 #include <linux/sched_clock.h>
  16 #include <linux/clk.h>
  17 #include <linux/clockchips.h>
  18 #include <linux/of_address.h>
  19 #include <linux/of_irq.h>
  20 #include <linux/timecounter.h>
  21 #include <asm/cpuinfo.h>
  22
  23 static void __iomem *timer_baseaddr;
  24
  25 static unsigned int freq_div_hz;
  26 static unsigned int timer_clock_freq;
  27
  28 #define TCSR0   (0x00)
  29 #define TLR0    (0x04)
  30 #define TCR0    (0x08)
  31 #define TCSR1   (0x10)
  32 #define TLR1    (0x14)
  33 #define TCR1    (0x18)
  34
  35 #define TCSR_MDT        (1<<0)
  36 #define TCSR_UDT        (1<<1)
  37 #define TCSR_GENT       (1<<2)
  38 #define TCSR_CAPT       (1<<3)
  39 #define TCSR_ARHT       (1<<4)
  40 #define TCSR_LOAD       (1<<5)
  41 #define TCSR_ENIT       (1<<6)
  42 #define TCSR_ENT        (1<<7)
  43 #define TCSR_TINT       (1<<8)
  44 #define TCSR_PWMA       (1<<9)
  45 #define TCSR_ENALL      (1<<10)
  46
  47 static unsigned int (*read_fn)(void __iomem *);
  48 static void (*write_fn)(u32, void __iomem *);
  49
  50 static void timer_write32(u32 val, void __iomem *addr)
  51 {
  52         iowrite32(val, addr);
  53 }
  54
  55 static unsigned int timer_read32(void __iomem *addr)
  56 {
  57         return ioread32(addr);
  58 }
  59
  60 static void timer_write32_be(u32 val, void __iomem *addr)
  61 {
  62         iowrite32be(val, addr);
  63 }
  64
  65 static unsigned int timer_read32_be(void __iomem *addr)
  66 {
  67         return ioread32be(addr);
  68 }
  69
  70 static inline void xilinx_timer0_stop(void)
  71 {
  72         write_fn(read_fn(timer_baseaddr + TCSR0) & ~TCSR_ENT,
  73                  timer_baseaddr + TCSR0);
  74 }
  75
  76 static inline void xilinx_timer0_start_periodic(unsigned long load_val)
  77 {
  78         if (!load_val)
  79                 load_val = 1;
  80         /* loading value to timer reg */
  81         write_fn(load_val, timer_baseaddr + TLR0);
  82
  83         /* load the initial value */
  84         write_fn(TCSR_LOAD, timer_baseaddr + TCSR0);
  85
  86         /* see timer data sheet for detail
  87          * !ENALL - don't enable 'em all
  88          * !PWMA - disable pwm
  89          * TINT - clear interrupt status
  90          * ENT- enable timer itself
  91          * ENIT - enable interrupt
  92          * !LOAD - clear the bit to let go
  93          * ARHT - auto reload
  94          * !CAPT - no external trigger
  95          * !GENT - no external signal
  96          * UDT - set the timer as down counter
  97          * !MDT0 - generate mode
  98          */
  99         write_fn(TCSR_TINT|TCSR_ENIT|TCSR_ENT|TCSR_ARHT|TCSR_UDT,
 100                  timer_baseaddr + TCSR0);
 101 }
 102
 103 static inline void xilinx_timer0_start_oneshot(unsigned long load_val)
 104 {
 105         if (!load_val)
 106                 load_val = 1;
 107         /* loading value to timer reg */
 108         write_fn(load_val, timer_baseaddr + TLR0);
 109
 110         /* load the initial value */
 111         write_fn(TCSR_LOAD, timer_baseaddr + TCSR0);
 112
 113         write_fn(TCSR_TINT|TCSR_ENIT|TCSR_ENT|TCSR_ARHT|TCSR_UDT,
 114                  timer_baseaddr + TCSR0);
 115 }
 116
 117 static int xilinx_timer_set_next_event(unsigned long delta,
 118                                         struct clock_event_device *dev)
 119 {
 120         pr_debug("%s: next event, delta %x\n", __func__, (u32)delta);
 121         xilinx_timer0_start_oneshot(delta);
 122         return 0;
 123 }
 124
 125 static int xilinx_timer_shutdown(struct clock_event_device *evt)
 126 {
 127         pr_info("%s\n", __func__);
 128         xilinx_timer0_stop();
 129         return 0;
 130 }
 131
 132 static int xilinx_timer_set_periodic(struct clock_event_device *evt)
 133 {
 134         pr_info("%s\n", __func__);
 135         xilinx_timer0_start_periodic(freq_div_hz);
 136         return 0;
 137 }
 138
 139 static struct clock_event_device clockevent_xilinx_timer = {
 140         .name                   = "xilinx_clockevent",
 141         .features               = CLOCK_EVT_FEAT_ONESHOT |
 142                                   CLOCK_EVT_FEAT_PERIODIC,
 143         .shift                  = 8,
 144         .rating                 = 300,
 145         .set_next_event         = xilinx_timer_set_next_event,
 146         .set_state_shutdown     = xilinx_timer_shutdown,
 147         .set_state_periodic     = xilinx_timer_set_periodic,
 148 };
 149
 150 static inline void timer_ack(void)
 151 {
 152         write_fn(read_fn(timer_baseaddr + TCSR0), timer_baseaddr + TCSR0);
 153 }
 154
 155 static irqreturn_t timer_interrupt(int irq, void *dev_id)
 156 {
 157         struct clock_event_device *evt = &clockevent_xilinx_timer;
 158 #ifdef CONFIG_HEART_BEAT
 159         microblaze_heartbeat();
 160 #endif
 161         timer_ack();
 162         evt->event_handler(evt);
 163         return IRQ_HANDLED;
 164 }
 165
 166 static struct irqaction timer_irqaction = {
 167         .handler = timer_interrupt,
 168         .flags = IRQF_TIMER,
 169         .name = "timer",
 170         .dev_id = &clockevent_xilinx_timer,
 171 };
 172
 173 static __init void xilinx_clockevent_init(void)
 174 {
 175         clockevent_xilinx_timer.mult =
 176                 div_sc(timer_clock_freq, NSEC_PER_SEC,
 177                                 clockevent_xilinx_timer.shift);
 178         clockevent_xilinx_timer.max_delta_ns =
 179                 clockevent_delta2ns((u32)~0, &clockevent_xilinx_timer);
 180         clockevent_xilinx_timer.min_delta_ns =
 181                 clockevent_delta2ns(1, &clockevent_xilinx_timer);
 182         clockevent_xilinx_timer.cpumask = cpumask_of(0);
 183         clockevents_register_device(&clockevent_xilinx_timer);
 184 }
 185
 186 static u64 xilinx_clock_read(void)
 187 {
 188         return read_fn(timer_baseaddr + TCR1);
 189 }
 190
 191 static cycle_t xilinx_read(struct clocksource *cs)
 192 {
 193         /* reading actual value of timer 1 */
 194         return (cycle_t)xilinx_clock_read();
 195 }
 196
 197 static struct timecounter xilinx_tc = {
 198         .cc = NULL,
 199 };
 200
 201 static cycle_t xilinx_cc_read(const struct cyclecounter *cc)
 202 {
 203         return xilinx_read(NULL);
 204 }
 205
 206 static struct cyclecounter xilinx_cc = {
 207         .read = xilinx_cc_read,
 208         .mask = CLOCKSOURCE_MASK(32),
 209         .shift = 8,
 210 };
 211
 212 static int __init init_xilinx_timecounter(void)
 213 {
 214         xilinx_cc.mult = div_sc(timer_clock_freq, NSEC_PER_SEC,
 215                                 xilinx_cc.shift);
 216
 217         timecounter_init(&xilinx_tc, &xilinx_cc, sched_clock());
 218
 219         return 0;
 220 }
 221
 222 static struct clocksource clocksource_microblaze = {
 223         .name           = "xilinx_clocksource",
 224         .rating         = 300,
 225         .read           = xilinx_read,
 226         .mask           = CLOCKSOURCE_MASK(32),
 227         .flags          = CLOCK_SOURCE_IS_CONTINUOUS,
 228 };
 229
 230 static int __init xilinx_clocksource_init(void)
 231 {
 232         if (clocksource_register_hz(&clocksource_microblaze, timer_clock_freq))
 233                 panic("failed to register clocksource");
 234
 235         /* stop timer1 */
 236         write_fn(read_fn(timer_baseaddr + TCSR1) & ~TCSR_ENT,
 237                  timer_baseaddr + TCSR1);
 238         /* start timer1 - up counting without interrupt */
 239         write_fn(TCSR_TINT|TCSR_ENT|TCSR_ARHT, timer_baseaddr + TCSR1);
 240
 241         /* register timecounter - for ftrace support */
 242         init_xilinx_timecounter();
 243         return 0;
 244 }
 245
 246 static void __init xilinx_timer_init(struct device_node *timer)
 247 {
 248         struct clk *clk;
 249         static int initialized;
 250         u32 irq;
 251         u32 timer_num = 1;
 252
 253         if (initialized)
 254                 return;
 255
 256         initialized = 1;
 257
 258         timer_baseaddr = of_iomap(timer, 0);
 259         if (!timer_baseaddr) {
 260                 pr_err("ERROR: invalid timer base address\n");
 261                 BUG();
 262         }
 263
 264         write_fn = timer_write32;
 265         read_fn = timer_read32;
 266
 267         write_fn(TCSR_MDT, timer_baseaddr + TCSR0);
 268         if (!(read_fn(timer_baseaddr + TCSR0) & TCSR_MDT)) {
 269                 write_fn = timer_write32_be;
 270                 read_fn = timer_read32_be;
 271         }
 272
 273         irq = irq_of_parse_and_map(timer, 0);
 274
 275         of_property_read_u32(timer, "xlnx,one-timer-only", &timer_num);
 276         if (timer_num) {
 277                 pr_emerg("Please enable two timers in HW\n");
 278                 BUG();
 279         }
 280
 281         pr_info("%s: irq=%d\n", timer->full_name, irq);
 282
 283         clk = of_clk_get(timer, 0);
 284         if (IS_ERR(clk)) {
 285                 pr_err("ERROR: timer CCF input clock not found\n");
 286                 /* If there is clock-frequency property than use it */
 287                 of_property_read_u32(timer, "clock-frequency",
 288                                     &timer_clock_freq);
 289         } else {
 290                 timer_clock_freq = clk_get_rate(clk);
 291         }
 292
 293         if (!timer_clock_freq) {
 294                 pr_err("ERROR: Using CPU clock frequency\n");
 295                 timer_clock_freq = cpuinfo.cpu_clock_freq;
 296         }
 297
 298         freq_div_hz = timer_clock_freq / HZ;
 299
 300         setup_irq(irq, &timer_irqaction);
 301 #ifdef CONFIG_HEART_BEAT
 302         microblaze_setup_heartbeat();
 303 #endif
 304         xilinx_clocksource_init();
 305         xilinx_clockevent_init();
 306
 307         sched_clock_register(xilinx_clock_read, 32, timer_clock_freq);
 308 }
 309
 310 CLOCKSOURCE_OF_DECLARE(xilinx_timer, "xlnx,xps-timer-1.00.a",
 311                        xilinx_timer_init);