FreeBSD/Linux Kernel Cross Reference
sys/arm/allwinner/timer.c

     /*-
      * Copyright (c) 2012 Ganbold Tsagaankhuu <ganbold@freebsd.org>
      * All rights reserved.
      *
      * Redistribution and use in source and binary forms, with or without
      * modification, are permitted provided that the following conditions
      * are met:
      * 1. Redistributions of source code must retain the above copyright
      *    notice, this list of conditions and the following disclaimer.
     * 2. Redistributions in binary form must reproduce the above copyright
     *    notice, this list of conditions and the following disclaimer in the
     *    documentation and/or other materials provided with the distribution.
     *
     * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
     * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
     * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     * SUCH DAMAGE.
     */
    
    #include <sys/cdefs.h>
    __FBSDID("$FreeBSD: releng/10.2/sys/arm/allwinner/timer.c 277113 2015-01-13 07:45:16Z ganbold $");
    
    #include <sys/param.h>
    #include <sys/systm.h>
    #include <sys/bus.h>
    #include <sys/kernel.h>
    #include <sys/module.h>
    #include <sys/malloc.h>
    #include <sys/rman.h>
    #include <sys/timeet.h>
    #include <sys/timetc.h>
    #include <sys/watchdog.h>
    #include <machine/bus.h>
    #include <machine/cpu.h>
    #include <machine/intr.h>
    
    #include <dev/fdt/fdt_common.h>
    #include <dev/ofw/openfirm.h>
    #include <dev/ofw/ofw_bus.h>
    #include <dev/ofw/ofw_bus_subr.h>
    
    #include <machine/bus.h>
    #include <machine/fdt.h>
    
    #include <sys/kdb.h>
    
    #include "a20/a20_cpu_cfg.h"
    
    /**
     * Timer registers addr
     *
     */
    #define SW_TIMER_IRQ_EN_REG     0x00
    #define SW_TIMER_IRQ_STA_REG    0x04
    #define SW_TIMER0_CTRL_REG      0x10
    #define SW_TIMER0_INT_VALUE_REG 0x14
    #define SW_TIMER0_CUR_VALUE_REG 0x18
    
    #define SW_COUNTER64LO_REG      0xa4
    #define SW_COUNTER64HI_REG      0xa8
    #define CNT64_CTRL_REG          0xa0
    
    #define CNT64_RL_EN             0x02 /* read latch enable */
    
    #define TIMER_ENABLE            (1<<0)
    #define TIMER_AUTORELOAD        (1<<1)
    #define TIMER_OSC24M            (1<<2) /* oscillator = 24mhz */
    #define TIMER_PRESCALAR         (0<<4) /* prescalar = 1 */
    
    #define SYS_TIMER_CLKSRC        24000000 /* clock source */
    
    struct a10_timer_softc {
            device_t        sc_dev;
            struct resource *res[2];
            bus_space_tag_t sc_bst;
            bus_space_handle_t sc_bsh;
            void            *sc_ih;         /* interrupt handler */
            uint32_t        sc_period;
            uint32_t        timer0_freq;
            struct eventtimer et;
            uint8_t         sc_timer_type;  /* 0 for A10, 1 for A20 */
    };
    
    int a10_timer_get_timerfreq(struct a10_timer_softc *);
    
    #define timer_read_4(sc, reg)   \
            bus_space_read_4(sc->sc_bst, sc->sc_bsh, reg)
    #define timer_write_4(sc, reg, val)     \
            bus_space_write_4(sc->sc_bst, sc->sc_bsh, reg, val)
    
    static u_int    a10_timer_get_timecount(struct timecounter *);
    static int      a10_timer_timer_start(struct eventtimer *,
       sbintime_t first, sbintime_t period);
   static int      a10_timer_timer_stop(struct eventtimer *);
   
   static uint64_t timer_read_counter64(void);
   
   static int a10_timer_initialized = 0;
   static int a10_timer_hardclock(void *);
   static int a10_timer_probe(device_t);
   static int a10_timer_attach(device_t);
   
   static struct timecounter a10_timer_timecounter = {
           .tc_name           = "a10_timer timer0",
           .tc_get_timecount  = a10_timer_get_timecount,
           .tc_counter_mask   = ~0u,
           .tc_frequency      = 0,
           .tc_quality        = 1000,
   };
   
   struct a10_timer_softc *a10_timer_sc = NULL;
   
   static struct resource_spec a10_timer_spec[] = {
           { SYS_RES_MEMORY,       0,      RF_ACTIVE },
           { SYS_RES_IRQ,          0,      RF_ACTIVE },
           { -1, 0 }
   };
   
   static uint64_t
   timer_read_counter64(void)
   {
           uint32_t lo, hi;
   
           /* In case of A20 get appropriate counter info */
           if (a10_timer_sc->sc_timer_type)
                   return (a20_read_counter64());
   
           /* Latch counter, wait for it to be ready to read. */
           timer_write_4(a10_timer_sc, CNT64_CTRL_REG, CNT64_RL_EN);
           while (timer_read_4(a10_timer_sc, CNT64_CTRL_REG) & CNT64_RL_EN)
                   continue;
   
           hi = timer_read_4(a10_timer_sc, SW_COUNTER64HI_REG);
           lo = timer_read_4(a10_timer_sc, SW_COUNTER64LO_REG);
   
           return (((uint64_t)hi << 32) | lo);
   }
   
   static int
   a10_timer_probe(device_t dev)
   {
           struct a10_timer_softc *sc;
   
           sc = device_get_softc(dev);
   
           if (ofw_bus_is_compatible(dev, "allwinner,sun4i-timer"))
                   sc->sc_timer_type = 0;
           else if (ofw_bus_is_compatible(dev, "allwinner,sun7i-timer"))
                   sc->sc_timer_type = 1;
           else
                   return (ENXIO);
   
           device_set_desc(dev, "Allwinner A10/A20 timer");
           return (BUS_PROBE_DEFAULT);
   }
   
   static int
   a10_timer_attach(device_t dev)
   {
           struct a10_timer_softc *sc;
           int err;
           uint32_t val;
   
           sc = device_get_softc(dev);
   
           if (bus_alloc_resources(dev, a10_timer_spec, sc->res)) {
                   device_printf(dev, "could not allocate resources\n");
                   return (ENXIO);
           }
   
           sc->sc_dev = dev;
           sc->sc_bst = rman_get_bustag(sc->res[0]);
           sc->sc_bsh = rman_get_bushandle(sc->res[0]);
   
           /* Setup and enable the timer interrupt */
           err = bus_setup_intr(dev, sc->res[1], INTR_TYPE_CLK, a10_timer_hardclock,
               NULL, sc, &sc->sc_ih);
           if (err != 0) {
                   bus_release_resources(dev, a10_timer_spec, sc->res);
                   device_printf(dev, "Unable to setup the clock irq handler, "
                       "err = %d\n", err);
                   return (ENXIO);
           }
   
           /* Set clock source to OSC24M, 16 pre-division */
           val = timer_read_4(sc, SW_TIMER0_CTRL_REG);
           val |= TIMER_PRESCALAR | TIMER_OSC24M;
           timer_write_4(sc, SW_TIMER0_CTRL_REG, val);
   
           /* Enable timer0 */
           val = timer_read_4(sc, SW_TIMER_IRQ_EN_REG);
           val |= TIMER_ENABLE;
           timer_write_4(sc, SW_TIMER_IRQ_EN_REG, val);
   
           sc->timer0_freq = SYS_TIMER_CLKSRC;
   
           /* Set desired frequency in event timer and timecounter */
           sc->et.et_frequency = sc->timer0_freq;
           sc->et.et_name = "a10_timer Eventtimer";
           sc->et.et_flags = ET_FLAGS_ONESHOT | ET_FLAGS_PERIODIC;
           sc->et.et_quality = 1000;
           sc->et.et_min_period = (0x00000005LLU << 32) / sc->et.et_frequency;
           sc->et.et_max_period = (0xfffffffeLLU << 32) / sc->et.et_frequency;
           sc->et.et_start = a10_timer_timer_start;
           sc->et.et_stop = a10_timer_timer_stop;
           sc->et.et_priv = sc;
           et_register(&sc->et);
   
           if (device_get_unit(dev) == 0)
                   a10_timer_sc = sc;
   
           a10_timer_timecounter.tc_frequency = sc->timer0_freq;
           tc_init(&a10_timer_timecounter);
   
           if (bootverbose) {
                   device_printf(sc->sc_dev, "clock: hz=%d stathz = %d\n", hz, stathz);
   
                   device_printf(sc->sc_dev, "event timer clock frequency %u\n", 
                       sc->timer0_freq);
                   device_printf(sc->sc_dev, "timecounter clock frequency %lld\n", 
                       a10_timer_timecounter.tc_frequency);
           }
   
           a10_timer_initialized = 1;
   
           return (0);
   }
   
   static int
   a10_timer_timer_start(struct eventtimer *et, sbintime_t first,
       sbintime_t period)
   {
           struct a10_timer_softc *sc;
           uint32_t count;
           uint32_t val;
   
           sc = (struct a10_timer_softc *)et->et_priv;
   
           if (period != 0)
                   sc->sc_period = ((uint32_t)et->et_frequency * period) >> 32;
           else
                   sc->sc_period = 0;
           if (first != 0)
                   count = ((uint32_t)et->et_frequency * first) >> 32;
           else
                   count = sc->sc_period;
   
           /* Update timer values */
           timer_write_4(sc, SW_TIMER0_INT_VALUE_REG, sc->sc_period);
           timer_write_4(sc, SW_TIMER0_CUR_VALUE_REG, count);
   
           val = timer_read_4(sc, SW_TIMER0_CTRL_REG);
           if (period != 0) {
                   /* periodic */
                   val |= TIMER_AUTORELOAD;
           } else {
                   /* oneshot */
                   val &= ~TIMER_AUTORELOAD;
           }
           /* Enable timer0 */
           val |= TIMER_ENABLE;
           timer_write_4(sc, SW_TIMER0_CTRL_REG, val);
   
           return (0);
   }
   
   static int
   a10_timer_timer_stop(struct eventtimer *et)
   {
           struct a10_timer_softc *sc;
           uint32_t val;
   
           sc = (struct a10_timer_softc *)et->et_priv;
   
           /* Disable timer0 */
           val = timer_read_4(sc, SW_TIMER0_CTRL_REG);
           val &= ~TIMER_ENABLE;
           timer_write_4(sc, SW_TIMER0_CTRL_REG, val);
   
           sc->sc_period = 0;
   
           return (0);
   }
   
   int
   a10_timer_get_timerfreq(struct a10_timer_softc *sc)
   {
           return (sc->timer0_freq);
   }
   
   static int
   a10_timer_hardclock(void *arg)
   {
           struct a10_timer_softc *sc;
           uint32_t val;
   
           sc = (struct a10_timer_softc *)arg;
   
           /* Clear interrupt pending bit. */
           timer_write_4(sc, SW_TIMER_IRQ_STA_REG, 0x1);
   
           val = timer_read_4(sc, SW_TIMER0_CTRL_REG);
           /*
            * Disabled autoreload and sc_period > 0 means 
            * timer_start was called with non NULL first value.
            * Now we will set periodic timer with the given period 
            * value.
            */
           if ((val & (1<<1)) == 0 && sc->sc_period > 0) {
                   /* Update timer */
                   timer_write_4(sc, SW_TIMER0_CUR_VALUE_REG, sc->sc_period);
   
                   /* Make periodic and enable */
                   val |= TIMER_AUTORELOAD | TIMER_ENABLE;
                   timer_write_4(sc, SW_TIMER0_CTRL_REG, val);
           }
   
           if (sc->et.et_active)
                   sc->et.et_event_cb(&sc->et, sc->et.et_arg);
   
           return (FILTER_HANDLED);
   }
   
   u_int
   a10_timer_get_timecount(struct timecounter *tc)
   {
   
           if (a10_timer_sc == NULL)
                   return (0);
   
           return ((u_int)timer_read_counter64());
   }
   
   static device_method_t a10_timer_methods[] = {
           DEVMETHOD(device_probe,         a10_timer_probe),
           DEVMETHOD(device_attach,        a10_timer_attach),
   
           DEVMETHOD_END
   };
   
   static driver_t a10_timer_driver = {
           "a10_timer",
           a10_timer_methods,
           sizeof(struct a10_timer_softc),
   };
   
   static devclass_t a10_timer_devclass;
   
   DRIVER_MODULE(a10_timer, simplebus, a10_timer_driver, a10_timer_devclass, 0, 0);
   
   void
   DELAY(int usec)
   {
           uint32_t counter;
           uint64_t end, now;
   
           if (!a10_timer_initialized) {
                   for (; usec > 0; usec--)
                           for (counter = 50; counter > 0; counter--)
                                   cpufunc_nullop();
                   return;
           }
   
           now = timer_read_counter64();
           end = now + (a10_timer_sc->timer0_freq / 1000000) * (usec + 1);
   
           while (now < end)
                   now = timer_read_counter64();
   }
   

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