sys/arm/broadcom/bcm2835/bcm2835_systimer.c

   1 /*
   2  * Copyright (c) 2012 Oleksandr Tymoshenko <gonzo@freebsd.org>
   3  * Copyright (c) 2012 Damjan Marion <dmarion@freebsd.org>
   4  * All rights reserved.
   5  *
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions
   8  * are met:
   9  * 1. Redistributions of source code must retain the above copyright
  10  *    notice, this list of conditions and the following disclaimer.
  11  * 2. Redistributions in binary form must reproduce the above copyright
  12  *    notice, this list of conditions and the following disclaimer in the
  13  *    documentation and/or other materials provided with the distribution.
  14  *
  15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  16  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  17  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  18  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  19  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  20  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  21  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  22  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  23  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  24  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  25  * SUCH DAMAGE.
  26  */
  27
  28 #include <sys/cdefs.h>
  29 __FBSDID("$FreeBSD$");
  30
  31 #include <sys/param.h>
  32 #include <sys/systm.h>
  33 #include <sys/bus.h>
  34 #include <sys/kernel.h>
  35 #include <sys/module.h>
  36 #include <sys/malloc.h>
  37 #include <sys/rman.h>
  38 #include <sys/timeet.h>
  39 #include <sys/timetc.h>
  40 #include <sys/watchdog.h>
  41 #include <machine/bus.h>
  42 #include <machine/cpu.h>
  43 #include <machine/intr.h>
  44 #include <machine/machdep.h>
  45
  46 #include <dev/ofw/openfirm.h>
  47 #include <dev/ofw/ofw_bus.h>
  48 #include <dev/ofw/ofw_bus_subr.h>
  49
  50 #include <machine/bus.h>
  51
  52 #define BCM2835_NUM_TIMERS      4
  53
  54 #define DEFAULT_TIMER           3
  55 #define DEFAULT_TIMER_NAME      "BCM2835-3"
  56 #define DEFAULT_FREQUENCY       1000000
  57 #define MIN_PERIOD              5LLU
  58
  59 #define SYSTIMER_CS     0x00
  60 #define SYSTIMER_CLO    0x04
  61 #define SYSTIMER_CHI    0x08
  62 #define SYSTIMER_C0     0x0C
  63 #define SYSTIMER_C1     0x10
  64 #define SYSTIMER_C2     0x14
  65 #define SYSTIMER_C3     0x18
  66
  67 struct systimer {
  68         int                     index;
  69         bool                    enabled;
  70         struct eventtimer       et;
  71 };
  72
  73 struct bcm_systimer_softc {
  74         struct resource*        mem_res;
  75         struct resource*        irq_res[BCM2835_NUM_TIMERS];
  76         void*                   intr_hl[BCM2835_NUM_TIMERS];
  77         uint32_t                sysclk_freq;
  78         bus_space_tag_t         bst;
  79         bus_space_handle_t      bsh;
  80         struct systimer         st[BCM2835_NUM_TIMERS];
  81 };
  82
  83 static struct resource_spec bcm_systimer_irq_spec[] = {
  84         { SYS_RES_IRQ,      0,  RF_ACTIVE },
  85         { SYS_RES_IRQ,      1,  RF_ACTIVE },
  86         { SYS_RES_IRQ,      2,  RF_ACTIVE },
  87         { SYS_RES_IRQ,      3,  RF_ACTIVE },
  88         { -1,               0,  0 }
  89 };
  90
  91 static struct bcm_systimer_softc *bcm_systimer_sc = NULL;
  92
  93 /* Read/Write macros for Timer used as timecounter */
  94 #define bcm_systimer_tc_read_4(reg)             \
  95         bus_space_read_4(bcm_systimer_sc->bst, \
  96                 bcm_systimer_sc->bsh, reg)
  97
  98 #define bcm_systimer_tc_write_4(reg, val)       \
  99         bus_space_write_4(bcm_systimer_sc->bst, \
 100                 bcm_systimer_sc->bsh, reg, val)
 101
 102 static unsigned bcm_systimer_tc_get_timecount(struct timecounter *);
 103
 104 static delay_func bcm_systimer_delay;
 105
 106 static struct timecounter bcm_systimer_tc = {
 107         .tc_name           = DEFAULT_TIMER_NAME,
 108         .tc_get_timecount  = bcm_systimer_tc_get_timecount,
 109         .tc_poll_pps       = NULL,
 110         .tc_counter_mask   = ~0u,
 111         .tc_frequency      = 0,
 112         .tc_quality        = 1000,
 113 };
 114
 115 static unsigned
 116 bcm_systimer_tc_get_timecount(struct timecounter *tc)
 117 {
 118         if (bcm_systimer_sc == NULL)
 119                 return (0);
 120
 121         return bcm_systimer_tc_read_4(SYSTIMER_CLO);
 122 }
 123
 124 static int
 125 bcm_systimer_start(struct eventtimer *et, sbintime_t first, sbintime_t period)
 126 {
 127         struct systimer *st = et->et_priv;
 128         uint32_t clo, clo1;
 129         uint32_t count;
 130         register_t s;
 131
 132         if (first != 0) {
 133
 134                 count = ((uint32_t)et->et_frequency * first) >> 32;
 135
 136                 s = intr_disable();
 137                 clo = bcm_systimer_tc_read_4(SYSTIMER_CLO);
 138 restart:
 139                 clo += count;
 140                 /*
 141                  * Clear pending interrupts
 142                  */
 143                 bcm_systimer_tc_write_4(SYSTIMER_CS, (1 << st->index));
 144                 bcm_systimer_tc_write_4(SYSTIMER_C0 + st->index*4, clo);
 145                 clo1 = bcm_systimer_tc_read_4(SYSTIMER_CLO);
 146                 if ((int32_t)(clo1 - clo) >= 0) {
 147                         count *= 2;
 148                         clo = clo1;
 149                         goto restart;
 150                 }
 151                 st->enabled = 1;
 152                 intr_restore(s);
 153
 154                 return (0);
 155         }
 156
 157         return (EINVAL);
 158 }
 159
 160 static int
 161 bcm_systimer_stop(struct eventtimer *et)
 162 {
 163         struct systimer *st = et->et_priv;
 164         st->enabled = 0;
 165
 166         return (0);
 167 }
 168
 169 static int
 170 bcm_systimer_intr(void *arg)
 171 {
 172         struct systimer *st = (struct systimer *)arg;
 173         uint32_t cs;
 174
 175         cs = bcm_systimer_tc_read_4(SYSTIMER_CS);
 176         if ((cs & (1 << st->index)) == 0)
 177                 return (FILTER_STRAY);
 178
 179         /* ACK interrupt */
 180         bcm_systimer_tc_write_4(SYSTIMER_CS, (1 << st->index));
 181         if (st->enabled) {
 182                 if (st->et.et_active) {
 183                         st->et.et_event_cb(&st->et, st->et.et_arg);
 184                 }
 185         }
 186
 187         return (FILTER_HANDLED);
 188 }
 189
 190 static int
 191 bcm_systimer_probe(device_t dev)
 192 {
 193
 194         if (!ofw_bus_status_okay(dev))
 195                 return (ENXIO);
 196
 197         if (ofw_bus_is_compatible(dev, "broadcom,bcm2835-system-timer")) {
 198                 device_set_desc(dev, "BCM2835 System Timer");
 199                 return (BUS_PROBE_DEFAULT);
 200         }
 201
 202         return (ENXIO);
 203 }
 204
 205 static int
 206 bcm_systimer_attach(device_t dev)
 207 {
 208         struct bcm_systimer_softc *sc = device_get_softc(dev);
 209         int err;
 210         int rid = 0;
 211
 212         if (bcm_systimer_sc != NULL)
 213                 return (EINVAL);
 214
 215         sc->mem_res = bus_alloc_resource_any(dev, SYS_RES_MEMORY, &rid, RF_ACTIVE);
 216         if (sc->mem_res == NULL) {
 217                 device_printf(dev, "could not allocate memory resource\n");
 218                 return (ENXIO);
 219         }
 220
 221         sc->bst = rman_get_bustag(sc->mem_res);
 222         sc->bsh = rman_get_bushandle(sc->mem_res);
 223
 224         /* Request the IRQ resources */
 225         err = bus_alloc_resources(dev, bcm_systimer_irq_spec,
 226                 sc->irq_res);
 227         if (err) {
 228                 device_printf(dev, "Error: could not allocate irq resources\n");
 229                 return (ENXIO);
 230         }
 231
 232         /* TODO: get frequency from FDT */
 233         sc->sysclk_freq = DEFAULT_FREQUENCY;
 234
 235         /* Setup and enable the timer */
 236         if (bus_setup_intr(dev, sc->irq_res[DEFAULT_TIMER], INTR_TYPE_CLK,
 237                         bcm_systimer_intr, NULL, &sc->st[DEFAULT_TIMER],
 238                         &sc->intr_hl[DEFAULT_TIMER]) != 0) {
 239                 bus_release_resources(dev, bcm_systimer_irq_spec,
 240                         sc->irq_res);
 241                 device_printf(dev, "Unable to setup the clock irq handler.\n");
 242                 return (ENXIO);
 243         }
 244
 245         sc->st[DEFAULT_TIMER].index = DEFAULT_TIMER;
 246         sc->st[DEFAULT_TIMER].enabled = 0;
 247         sc->st[DEFAULT_TIMER].et.et_name = DEFAULT_TIMER_NAME;
 248         sc->st[DEFAULT_TIMER].et.et_flags = ET_FLAGS_ONESHOT;
 249         sc->st[DEFAULT_TIMER].et.et_quality = 1000;
 250         sc->st[DEFAULT_TIMER].et.et_frequency = sc->sysclk_freq;
 251         sc->st[DEFAULT_TIMER].et.et_min_period =
 252             (MIN_PERIOD << 32) / sc->st[DEFAULT_TIMER].et.et_frequency + 1;
 253         sc->st[DEFAULT_TIMER].et.et_max_period =
 254             (0x7ffffffeLLU << 32) / sc->st[DEFAULT_TIMER].et.et_frequency;
 255         sc->st[DEFAULT_TIMER].et.et_start = bcm_systimer_start;
 256         sc->st[DEFAULT_TIMER].et.et_stop = bcm_systimer_stop;
 257         sc->st[DEFAULT_TIMER].et.et_priv = &sc->st[DEFAULT_TIMER];
 258         et_register(&sc->st[DEFAULT_TIMER].et);
 259
 260         bcm_systimer_sc = sc;
 261
 262         if (device_get_unit(dev) == 0)
 263                 arm_set_delay(bcm_systimer_delay, sc);
 264
 265         bcm_systimer_tc.tc_frequency = DEFAULT_FREQUENCY;
 266         tc_init(&bcm_systimer_tc);
 267
 268         return (0);
 269 }
 270
 271 static device_method_t bcm_systimer_methods[] = {
 272         DEVMETHOD(device_probe,         bcm_systimer_probe),
 273         DEVMETHOD(device_attach,        bcm_systimer_attach),
 274         { 0, 0 }
 275 };
 276
 277 static driver_t bcm_systimer_driver = {
 278         "systimer",
 279         bcm_systimer_methods,
 280         sizeof(struct bcm_systimer_softc),
 281 };
 282
 283 static devclass_t bcm_systimer_devclass;
 284
 285 DRIVER_MODULE(bcm_systimer, simplebus, bcm_systimer_driver, bcm_systimer_devclass, 0, 0);
 286
 287 static void
 288 bcm_systimer_delay(int usec, void *arg)
 289 {
 290         struct bcm_systimer_softc *sc;
 291         int32_t counts;
 292         uint32_t first, last;
 293
 294         sc = (struct bcm_systimer_softc *) arg;
 295
 296         /* Get the number of times to count */
 297         counts = usec * (bcm_systimer_tc.tc_frequency / 1000000) + 1;
 298
 299         first = bcm_systimer_tc_read_4(SYSTIMER_CLO);
 300
 301         while (counts > 0) {
 302                 last = bcm_systimer_tc_read_4(SYSTIMER_CLO);
 303                 if (last == first)
 304                         continue;
 305                 if (last>first) {
 306                         counts -= (int32_t)(last - first);
 307                 } else {
 308                         counts -= (int32_t)((0xFFFFFFFF - first) + last);
 309                 }
 310                 first = last;
 311         }
 312 }