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/sched_clock.h>
  17 #include <linux/clk.h>
  18 #include <linux/clockchips.h>
  19 #include <linux/of_address.h>
  20 #include <linux/of_irq.h>
  21 #include <linux/timecounter.h>
  22 #include <asm/cpuinfo.h>
  23
  24 static void __iomem *timer_baseaddr;
  25
  26 static unsigned int freq_div_hz;
  27 static unsigned int timer_clock_freq;
  28
  29 #define TCSR0   (0x00)
  30 #define TLR0    (0x04)
  31 #define TCR0    (0x08)
  32 #define TCSR1   (0x10)
  33 #define TLR1    (0x14)
  34 #define TCR1    (0x18)
  35
  36 #define TCSR_MDT        (1<<0)
  37 #define TCSR_UDT        (1<<1)
  38 #define TCSR_GENT       (1<<2)
  39 #define TCSR_CAPT       (1<<3)
  40 #define TCSR_ARHT       (1<<4)
  41 #define TCSR_LOAD       (1<<5)
  42 #define TCSR_ENIT       (1<<6)
  43 #define TCSR_ENT        (1<<7)
  44 #define TCSR_TINT       (1<<8)
  45 #define TCSR_PWMA       (1<<9)
  46 #define TCSR_ENALL      (1<<10)
  47
  48 static unsigned int (*read_fn)(void __iomem *);
  49 static void (*write_fn)(u32, void __iomem *);
  50
  51 static void timer_write32(u32 val, void __iomem *addr)
  52 {
  53         iowrite32(val, addr);
  54 }
  55
  56 static unsigned int timer_read32(void __iomem *addr)
  57 {
  58         return ioread32(addr);
  59 }
  60
  61 static void timer_write32_be(u32 val, void __iomem *addr)
  62 {
  63         iowrite32be(val, addr);
  64 }
  65
  66 static unsigned int timer_read32_be(void __iomem *addr)
  67 {
  68         return ioread32be(addr);
  69 }
  70
  71 static inline void xilinx_timer0_stop(void)
  72 {
  73         write_fn(read_fn(timer_baseaddr + TCSR0) & ~TCSR_ENT,
  74                  timer_baseaddr + TCSR0);
  75 }
  76
  77 static inline void xilinx_timer0_start_periodic(unsigned long load_val)
  78 {
  79         if (!load_val)
  80                 load_val = 1;
  81         /* loading value to timer reg */
  82         write_fn(load_val, timer_baseaddr + TLR0);
  83
  84         /* load the initial value */
  85         write_fn(TCSR_LOAD, timer_baseaddr + TCSR0);
  86
  87         /* see timer data sheet for detail
  88          * !ENALL - don't enable 'em all
  89          * !PWMA - disable pwm
  90          * TINT - clear interrupt status
  91          * ENT- enable timer itself
  92          * ENIT - enable interrupt
  93          * !LOAD - clear the bit to let go
  94          * ARHT - auto reload
  95          * !CAPT - no external trigger
  96          * !GENT - no external signal
  97          * UDT - set the timer as down counter
  98          * !MDT0 - generate mode
  99          */
 100         write_fn(TCSR_TINT|TCSR_ENIT|TCSR_ENT|TCSR_ARHT|TCSR_UDT,
 101                  timer_baseaddr + TCSR0);
 102 }
 103
 104 static inline void xilinx_timer0_start_oneshot(unsigned long load_val)
 105 {
 106         if (!load_val)
 107                 load_val = 1;
 108         /* loading value to timer reg */
 109         write_fn(load_val, timer_baseaddr + TLR0);
 110
 111         /* load the initial value */
 112         write_fn(TCSR_LOAD, timer_baseaddr + TCSR0);
 113
 114         write_fn(TCSR_TINT|TCSR_ENIT|TCSR_ENT|TCSR_ARHT|TCSR_UDT,
 115                  timer_baseaddr + TCSR0);
 116 }
 117
 118 static int xilinx_timer_set_next_event(unsigned long delta,
 119                                         struct clock_event_device *dev)
 120 {
 121         pr_debug("%s: next event, delta %x\n", __func__, (u32)delta);
 122         xilinx_timer0_start_oneshot(delta);
 123         return 0;
 124 }
 125
 126 static int xilinx_timer_shutdown(struct clock_event_device *evt)
 127 {
 128         pr_info("%s\n", __func__);
 129         xilinx_timer0_stop();
 130         return 0;
 131 }
 132
 133 static int xilinx_timer_set_periodic(struct clock_event_device *evt)
 134 {
 135         pr_info("%s\n", __func__);
 136         xilinx_timer0_start_periodic(freq_div_hz);
 137         return 0;
 138 }
 139
 140 static struct clock_event_device clockevent_xilinx_timer = {
 141         .name                   = "xilinx_clockevent",
 142         .features               = CLOCK_EVT_FEAT_ONESHOT |
 143                                   CLOCK_EVT_FEAT_PERIODIC,
 144         .shift                  = 8,
 145         .rating                 = 300,
 146         .set_next_event         = xilinx_timer_set_next_event,
 147         .set_state_shutdown     = xilinx_timer_shutdown,
 148         .set_state_periodic     = xilinx_timer_set_periodic,
 149 };
 150
 151 static inline void timer_ack(void)
 152 {
 153         write_fn(read_fn(timer_baseaddr + TCSR0), timer_baseaddr + TCSR0);
 154 }
 155
 156 static irqreturn_t timer_interrupt(int irq, void *dev_id)
 157 {
 158         struct clock_event_device *evt = &clockevent_xilinx_timer;
 159         timer_ack();
 160         evt->event_handler(evt);
 161         return IRQ_HANDLED;
 162 }
 163
 164 static __init int xilinx_clockevent_init(void)
 165 {
 166         clockevent_xilinx_timer.mult =
 167                 div_sc(timer_clock_freq, NSEC_PER_SEC,
 168                                 clockevent_xilinx_timer.shift);
 169         clockevent_xilinx_timer.max_delta_ns =
 170                 clockevent_delta2ns((u32)~0, &clockevent_xilinx_timer);
 171         clockevent_xilinx_timer.max_delta_ticks = (u32)~0;
 172         clockevent_xilinx_timer.min_delta_ns =
 173                 clockevent_delta2ns(1, &clockevent_xilinx_timer);
 174         clockevent_xilinx_timer.min_delta_ticks = 1;
 175         clockevent_xilinx_timer.cpumask = cpumask_of(0);
 176         clockevents_register_device(&clockevent_xilinx_timer);
 177
 178         return 0;
 179 }
 180
 181 static u64 xilinx_clock_read(void)
 182 {
 183         return read_fn(timer_baseaddr + TCR1);
 184 }
 185
 186 static u64 xilinx_read(struct clocksource *cs)
 187 {
 188         /* reading actual value of timer 1 */
 189         return (u64)xilinx_clock_read();
 190 }
 191
 192 static struct timecounter xilinx_tc = {
 193         .cc = NULL,
 194 };
 195
 196 static u64 xilinx_cc_read(const struct cyclecounter *cc)
 197 {
 198         return xilinx_read(NULL);
 199 }
 200
 201 static struct cyclecounter xilinx_cc = {
 202         .read = xilinx_cc_read,
 203         .mask = CLOCKSOURCE_MASK(32),
 204         .shift = 8,
 205 };
 206
 207 static int __init init_xilinx_timecounter(void)
 208 {
 209         xilinx_cc.mult = div_sc(timer_clock_freq, NSEC_PER_SEC,
 210                                 xilinx_cc.shift);
 211
 212         timecounter_init(&xilinx_tc, &xilinx_cc, sched_clock());
 213
 214         return 0;
 215 }
 216
 217 static struct clocksource clocksource_microblaze = {
 218         .name           = "xilinx_clocksource",
 219         .rating         = 300,
 220         .read           = xilinx_read,
 221         .mask           = CLOCKSOURCE_MASK(32),
 222         .flags          = CLOCK_SOURCE_IS_CONTINUOUS,
 223 };
 224
 225 static int __init xilinx_clocksource_init(void)
 226 {
 227         int ret;
 228
 229         ret = clocksource_register_hz(&clocksource_microblaze,
 230                                       timer_clock_freq);
 231         if (ret) {
 232                 pr_err("failed to register clocksource");
 233                 return ret;
 234         }
 235
 236         /* stop timer1 */
 237         write_fn(read_fn(timer_baseaddr + TCSR1) & ~TCSR_ENT,
 238                  timer_baseaddr + TCSR1);
 239         /* start timer1 - up counting without interrupt */
 240         write_fn(TCSR_TINT|TCSR_ENT|TCSR_ARHT, timer_baseaddr + TCSR1);
 241
 242         /* register timecounter - for ftrace support */
 243         return init_xilinx_timecounter();
 244 }
 245
 246 static int __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         int ret;
 253
 254         if (initialized)
 255                 return -EINVAL;
 256
 257         initialized = 1;
 258
 259         timer_baseaddr = of_iomap(timer, 0);
 260         if (!timer_baseaddr) {
 261                 pr_err("ERROR: invalid timer base address\n");
 262                 return -ENXIO;
 263         }
 264
 265         write_fn = timer_write32;
 266         read_fn = timer_read32;
 267
 268         write_fn(TCSR_MDT, timer_baseaddr + TCSR0);
 269         if (!(read_fn(timer_baseaddr + TCSR0) & TCSR_MDT)) {
 270                 write_fn = timer_write32_be;
 271                 read_fn = timer_read32_be;
 272         }
 273
 274         irq = irq_of_parse_and_map(timer, 0);
 275         if (irq <= 0) {
 276                 pr_err("Failed to parse and map irq");
 277                 return -EINVAL;
 278         }
 279
 280         of_property_read_u32(timer, "xlnx,one-timer-only", &timer_num);
 281         if (timer_num) {
 282                 pr_err("Please enable two timers in HW\n");
 283                 return -EINVAL;
 284         }
 285
 286         pr_info("%pOF: irq=%d\n", timer, irq);
 287
 288         clk = of_clk_get(timer, 0);
 289         if (IS_ERR(clk)) {
 290                 pr_err("ERROR: timer CCF input clock not found\n");
 291                 /* If there is clock-frequency property than use it */
 292                 of_property_read_u32(timer, "clock-frequency",
 293                                     &timer_clock_freq);
 294         } else {
 295                 timer_clock_freq = clk_get_rate(clk);
 296         }
 297
 298         if (!timer_clock_freq) {
 299                 pr_err("ERROR: Using CPU clock frequency\n");
 300                 timer_clock_freq = cpuinfo.cpu_clock_freq;
 301         }
 302
 303         freq_div_hz = timer_clock_freq / HZ;
 304
 305         ret = request_irq(irq, timer_interrupt, IRQF_TIMER, "timer",
 306                           &clockevent_xilinx_timer);
 307         if (ret) {
 308                 pr_err("Failed to setup IRQ");
 309                 return ret;
 310         }
 311
 312         ret = xilinx_clocksource_init();
 313         if (ret)
 314                 return ret;
 315
 316         ret = xilinx_clockevent_init();
 317         if (ret)
 318                 return ret;
 319
 320         sched_clock_register(xilinx_clock_read, 32, timer_clock_freq);
 321
 322         return 0;
 323 }
 324
 325 TIMER_OF_DECLARE(xilinx_timer, "xlnx,xps-timer-1.00.a",
 326                        xilinx_timer_init);