FreeBSD/Linux Kernel Cross Reference
sys/x86/isa/atrtc.c

     /*-
      * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
      *
      * Copyright (c) 2008 Poul-Henning Kamp
      * Copyright (c) 2010 Alexander Motin <mav@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.
     *
     * $FreeBSD$
     */
    
    #include <sys/cdefs.h>
    __FBSDID("$FreeBSD$");
    
    #include "opt_acpi.h"
    #include "opt_isa.h"
    
    #include <sys/param.h>
    #include <sys/systm.h>
    #include <sys/bus.h>
    #include <sys/clock.h>
    #include <sys/lock.h>
    #include <sys/mutex.h>
    #include <sys/kdb.h>
    #include <sys/kernel.h>
    #include <sys/module.h>
    #include <sys/proc.h>
    #include <sys/rman.h>
    #include <sys/timeet.h>
    
    #include <isa/rtc.h>
    #ifdef DEV_ISA
    #include <isa/isareg.h>
    #include <isa/isavar.h>
    #endif
    #include <machine/intr_machdep.h>
    #include "clock_if.h"
    #ifdef DEV_ACPI
    #include <contrib/dev/acpica/include/acpi.h>
    #include <contrib/dev/acpica/include/accommon.h>
    #include <dev/acpica/acpivar.h>
    #include <machine/md_var.h>
    #endif
    
    /*
     * atrtc_lock protects low-level access to individual hardware registers.
     * atrtc_time_lock protects the entire sequence of accessing multiple registers
     * to read or write the date and time.
     */
    static struct mtx atrtc_lock;
    MTX_SYSINIT(atrtc_lock_init, &atrtc_lock, "atrtc", MTX_SPIN);
    
    /* Force RTC enabled/disabled. */
    static int atrtc_enabled = -1;
    TUNABLE_INT("hw.atrtc.enabled", &atrtc_enabled);
    
    struct mtx atrtc_time_lock;
    MTX_SYSINIT(atrtc_time_lock_init, &atrtc_time_lock, "atrtc_time", MTX_DEF);
    
    int     atrtcclock_disable = 0;
    
    static  int     rtc_century = 0;
    static  int     rtc_reg = -1;
    static  u_char  rtc_statusa = RTCSA_DIVIDER | RTCSA_NOPROF;
    static  u_char  rtc_statusb = RTCSB_24HR;
    
    #ifdef DEV_ACPI
    #define _COMPONENT      ACPI_TIMER
    ACPI_MODULE_NAME("ATRTC")
    #endif
    
    /*
     * RTC support routines
     */
    
    static inline u_char
    rtcin_locked(int reg)
    {
    
           if (rtc_reg != reg) {
                   inb(0x84);
                   outb(IO_RTC, reg);
                   rtc_reg = reg;
                   inb(0x84);
           }
           return (inb(IO_RTC + 1));
   }
   
   static inline void
   rtcout_locked(int reg, u_char val)
   {
   
           if (rtc_reg != reg) {
                   inb(0x84);
                   outb(IO_RTC, reg);
                   rtc_reg = reg;
                   inb(0x84);
           }
           outb(IO_RTC + 1, val);
           inb(0x84);
   }
   
   int
   rtcin(int reg)
   {
           u_char val;
   
           mtx_lock_spin(&atrtc_lock);
           val = rtcin_locked(reg);
           mtx_unlock_spin(&atrtc_lock);
           return (val);
   }
   
   void
   writertc(int reg, u_char val)
   {
   
           mtx_lock_spin(&atrtc_lock);
           rtcout_locked(reg, val);
           mtx_unlock_spin(&atrtc_lock);
   }
   
   static void
   atrtc_start(void)
   {
   
           mtx_lock_spin(&atrtc_lock);
           rtcout_locked(RTC_STATUSA, rtc_statusa);
           rtcout_locked(RTC_STATUSB, RTCSB_24HR);
           mtx_unlock_spin(&atrtc_lock);
   }
   
   static void
   atrtc_rate(unsigned rate)
   {
   
           rtc_statusa = RTCSA_DIVIDER | rate;
           writertc(RTC_STATUSA, rtc_statusa);
   }
   
   static void
   atrtc_enable_intr(void)
   {
   
           rtc_statusb |= RTCSB_PINTR;
           mtx_lock_spin(&atrtc_lock);
           rtcout_locked(RTC_STATUSB, rtc_statusb);
           rtcin_locked(RTC_INTR);
           mtx_unlock_spin(&atrtc_lock);
   }
   
   static void
   atrtc_disable_intr(void)
   {
   
           rtc_statusb &= ~RTCSB_PINTR;
           mtx_lock_spin(&atrtc_lock);
           rtcout_locked(RTC_STATUSB, rtc_statusb);
           rtcin_locked(RTC_INTR);
           mtx_unlock_spin(&atrtc_lock);
   }
   
   void
   atrtc_restore(void)
   {
   
           /* Restore all of the RTC's "status" (actually, control) registers. */
           mtx_lock_spin(&atrtc_lock);
           rtcin_locked(RTC_STATUSA);      /* dummy to get rtc_reg set */
           rtcout_locked(RTC_STATUSB, RTCSB_24HR);
           rtcout_locked(RTC_STATUSA, rtc_statusa);
           rtcout_locked(RTC_STATUSB, rtc_statusb);
           rtcin_locked(RTC_INTR);
           mtx_unlock_spin(&atrtc_lock);
   }
   
   /**********************************************************************
    * RTC driver for subr_rtc
    */
   
   struct atrtc_softc {
           int port_rid, intr_rid;
           struct resource *port_res;
           struct resource *intr_res;
           void *intr_handler;
           struct eventtimer et;
   #ifdef DEV_ACPI
           ACPI_HANDLE acpi_handle;
   #endif
   };
   
   static int
   rtc_start(struct eventtimer *et, sbintime_t first, sbintime_t period)
   {
   
           atrtc_rate(max(fls(period + (period >> 1)) - 17, 1));
           atrtc_enable_intr();
           return (0);
   }
   
   static int
   rtc_stop(struct eventtimer *et)
   {
   
           atrtc_disable_intr();
           return (0);
   }
   
   /*
    * This routine receives statistical clock interrupts from the RTC.
    * As explained above, these occur at 128 interrupts per second.
    * When profiling, we receive interrupts at a rate of 1024 Hz.
    *
    * This does not actually add as much overhead as it sounds, because
    * when the statistical clock is active, the hardclock driver no longer
    * needs to keep (inaccurate) statistics on its own.  This decouples
    * statistics gathering from scheduling interrupts.
    *
    * The RTC chip requires that we read status register C (RTC_INTR)
    * to acknowledge an interrupt, before it will generate the next one.
    * Under high interrupt load, rtcintr() can be indefinitely delayed and
    * the clock can tick immediately after the read from RTC_INTR.  In this
    * case, the mc146818A interrupt signal will not drop for long enough
    * to register with the 8259 PIC.  If an interrupt is missed, the stat
    * clock will halt, considerably degrading system performance.  This is
    * why we use 'while' rather than a more straightforward 'if' below.
    * Stat clock ticks can still be lost, causing minor loss of accuracy
    * in the statistics, but the stat clock will no longer stop.
    */
   static int
   rtc_intr(void *arg)
   {
           struct atrtc_softc *sc = (struct atrtc_softc *)arg;
           int flag = 0;
   
           while (rtcin(RTC_INTR) & RTCIR_PERIOD) {
                   flag = 1;
                   if (sc->et.et_active)
                           sc->et.et_event_cb(&sc->et, sc->et.et_arg);
           }
           return(flag ? FILTER_HANDLED : FILTER_STRAY);
   }
   
   #ifdef DEV_ACPI
   /*
    *  ACPI RTC CMOS address space handler
    */
   #define ATRTC_LAST_REG  0x40
   
   static void
   rtcin_region(int reg, void *buf, int len)
   {
           u_char *ptr = buf;
   
           /* Drop lock after each IO as intr and settime have greater priority */
           while (len-- > 0)
                   *ptr++ = rtcin(reg++) & 0xff;
   }
   
   static void
   rtcout_region(int reg, const void *buf, int len)
   {
           const u_char *ptr = buf;
   
           while (len-- > 0)
                   writertc(reg++, *ptr++);
   }
   
   static bool
   atrtc_check_cmos_access(bool is_read, ACPI_PHYSICAL_ADDRESS addr, UINT32 len)
   {
   
           /* Block address space wrapping on out-of-bound access */
           if (addr >= ATRTC_LAST_REG || addr + len > ATRTC_LAST_REG)
                   return (false);
   
           if (is_read) {
                   /* Reading 0x0C will muck with interrupts */
                   if (addr <= RTC_INTR && addr + len > RTC_INTR)
                           return (false);
           } else {
                   /*
                    * Allow single-byte writes to alarm registers and
                    * multi-byte writes to addr >= 0x30, else deny.
                    */
                   if (!((len == 1 && (addr == RTC_SECALRM ||
                                       addr == RTC_MINALRM ||
                                       addr == RTC_HRSALRM)) ||
                         addr >= 0x30))
                           return (false);
           }
           return (true);
   }
   
   static ACPI_STATUS
   atrtc_acpi_cmos_handler(UINT32 func, ACPI_PHYSICAL_ADDRESS addr,
       UINT32 bitwidth, UINT64 *value, void *context, void *region_context)
   {
           device_t dev = context;
           UINT32 bytewidth = howmany(bitwidth, 8);
           bool is_read = func == ACPI_READ;
   
           /* ACPICA is very verbose on CMOS handler failures, so we, too */
   #define CMOS_HANDLER_ERR(fmt, ...) \
           device_printf(dev, "ACPI [SystemCMOS] handler: " fmt, ##__VA_ARGS__)
   
           ACPI_FUNCTION_TRACE((char *)(uintptr_t)__func__);
   
           if (value == NULL) {
                   CMOS_HANDLER_ERR("NULL parameter\n");
                   return (AE_BAD_PARAMETER);
           }
           if (bitwidth == 0 || (bitwidth & 0x07) != 0) {
                   CMOS_HANDLER_ERR("Invalid bitwidth: %u\n", bitwidth);
                   return (AE_BAD_PARAMETER);
           }
           if (!atrtc_check_cmos_access(is_read, addr, bytewidth)) {
                   CMOS_HANDLER_ERR("%s access rejected: addr=%#04jx, len=%u\n",
                       is_read ? "Read" : "Write", (uintmax_t)addr, bytewidth);
                   return (AE_BAD_PARAMETER);
           }
   
           switch (func) {
           case ACPI_READ:
                   rtcin_region(addr, value, bytewidth);
                   break;
           case ACPI_WRITE:
                   rtcout_region(addr, value, bytewidth);
                   break;
           default:
                   CMOS_HANDLER_ERR("Invalid function: %u\n", func);
                   return (AE_BAD_PARAMETER);
           }
   
           ACPI_VPRINT(dev, acpi_device_get_parent_softc(dev),
               "ACPI RTC CMOS %s access: addr=%#04x, len=%u, val=%*D\n",
               is_read ? "read" : "write", (unsigned)addr, bytewidth,
               bytewidth, value, " ");
   
           return (AE_OK);
   }
   
   static int
   atrtc_reg_acpi_cmos_handler(device_t dev)
   {
           struct atrtc_softc *sc = device_get_softc(dev);
   
           ACPI_FUNCTION_TRACE((char *)(uintptr_t) __func__);
   
           /* Don't handle address space events if driver is disabled. */
           if (acpi_disabled("atrtc"))
                   return (ENXIO);
   
           if (ACPI_FAILURE(AcpiGetHandle(ACPI_ROOT_OBJECT, "\\_SB_", &sc->acpi_handle))) {
                   return (ENXIO);
           }
   
           if (sc->acpi_handle == NULL ||
               ACPI_FAILURE(AcpiInstallAddressSpaceHandler(sc->acpi_handle,
                 ACPI_ADR_SPACE_CMOS, atrtc_acpi_cmos_handler, NULL, dev))) {
                   sc->acpi_handle = NULL;
                   device_printf(dev,
                       "Can't register ACPI CMOS address space handler\n");
                   return (ENXIO);
           }
   
           return (0);
   }
   
   static int
   atrtc_unreg_acpi_cmos_handler(device_t dev)
   {
           struct atrtc_softc *sc = device_get_softc(dev);
   
           ACPI_FUNCTION_TRACE((char *)(uintptr_t) __func__);
   
           if (sc->acpi_handle != NULL)
                   AcpiRemoveAddressSpaceHandler(sc->acpi_handle,
                       ACPI_ADR_SPACE_CMOS, atrtc_acpi_cmos_handler);
   
           return (0);
   }
   #endif  /* DEV_ACPI */
   
   /*
    * Attach to the ISA PnP descriptors for the timer and realtime clock.
    */
   static struct isa_pnp_id atrtc_ids[] = {
           { 0x000bd041 /* PNP0B00 */, "AT realtime clock" },
           { 0 }
   };
   
   static bool
   atrtc_acpi_disabled(void)
   {
   #ifdef DEV_ACPI
           uint16_t flags;
   
           if (!acpi_get_fadt_bootflags(&flags))
                   return (false);
           return ((flags & ACPI_FADT_NO_CMOS_RTC) != 0);
   #else
           return (false);
   #endif
   }
   
   static int
   rtc_acpi_century_get(void)
   {
   #ifdef DEV_ACPI
           ACPI_TABLE_FADT *fadt;
           vm_paddr_t physaddr;
           int century;
   
           physaddr = acpi_find_table(ACPI_SIG_FADT);
           if (physaddr == 0)
                   return (0);
   
           fadt = acpi_map_table(physaddr, ACPI_SIG_FADT);
           if (fadt == NULL)
                   return (0);
   
           century = fadt->Century;
           acpi_unmap_table(fadt);
   
           return (century);
   #else
           return (0);
   #endif
   }
   
   static int
   atrtc_probe(device_t dev)
   {
           int result;
   
           if ((atrtc_enabled == -1 && atrtc_acpi_disabled()) ||
               (atrtc_enabled == 0))
                   return (ENXIO);
   
           result = ISA_PNP_PROBE(device_get_parent(dev), dev, atrtc_ids);
           /* ENOENT means no PnP-ID, device is hinted. */
           if (result == ENOENT) {
                   device_set_desc(dev, "AT realtime clock");
                   return (BUS_PROBE_LOW_PRIORITY);
           }
           rtc_century = rtc_acpi_century_get();
           return (result);
   }
   
   static int
   atrtc_attach(device_t dev)
   {
           struct atrtc_softc *sc;
           rman_res_t s;
           int i;
   
           sc = device_get_softc(dev);
           sc->port_res = bus_alloc_resource(dev, SYS_RES_IOPORT, &sc->port_rid,
               IO_RTC, IO_RTC + 1, 2, RF_ACTIVE);
           if (sc->port_res == NULL)
                   device_printf(dev, "Warning: Couldn't map I/O.\n");
           atrtc_start();
           clock_register(dev, 1000000);
           bzero(&sc->et, sizeof(struct eventtimer));
           if (!atrtcclock_disable &&
               (resource_int_value(device_get_name(dev), device_get_unit(dev),
                "clock", &i) != 0 || i != 0)) {
                   sc->intr_rid = 0;
                   while (bus_get_resource(dev, SYS_RES_IRQ, sc->intr_rid,
                       &s, NULL) == 0 && s != 8)
                           sc->intr_rid++;
                   sc->intr_res = bus_alloc_resource(dev, SYS_RES_IRQ,
                       &sc->intr_rid, 8, 8, 1, RF_ACTIVE);
                   if (sc->intr_res == NULL) {
                           device_printf(dev, "Can't map interrupt.\n");
                           return (0);
                   } else if ((bus_setup_intr(dev, sc->intr_res, INTR_TYPE_CLK,
                       rtc_intr, NULL, sc, &sc->intr_handler))) {
                           device_printf(dev, "Can't setup interrupt.\n");
                           return (0);
                   } else { 
                           /* Bind IRQ to BSP to avoid live migration. */
                           bus_bind_intr(dev, sc->intr_res, 0);
                   }
                   sc->et.et_name = "RTC";
                   sc->et.et_flags = ET_FLAGS_PERIODIC | ET_FLAGS_POW2DIV;
                   sc->et.et_quality = 0;
                   sc->et.et_frequency = 32768;
                   sc->et.et_min_period = 0x00080000;
                   sc->et.et_max_period = 0x80000000;
                   sc->et.et_start = rtc_start;
                   sc->et.et_stop = rtc_stop;
                   sc->et.et_priv = dev;
                   et_register(&sc->et);
           }
           return(0);
   }
   
   static int
   atrtc_isa_attach(device_t dev)
   {
   
           return (atrtc_attach(dev));
   }
   
   #ifdef DEV_ACPI
   static int
   atrtc_acpi_attach(device_t dev)
   {
           int ret;
   
           ret = atrtc_attach(dev);
           if (ret)
                   return (ret);
   
           (void)atrtc_reg_acpi_cmos_handler(dev);
   
           return (0);
   }
   
   static int
   atrtc_acpi_detach(device_t dev)
   {
   
           (void)atrtc_unreg_acpi_cmos_handler(dev);
           return (0);
   }
   #endif  /* DEV_ACPI */
   
   static int
   atrtc_resume(device_t dev)
   {
   
           atrtc_restore();
           return(0);
   }
   
   static int
   atrtc_settime(device_t dev __unused, struct timespec *ts)
   {
           struct bcd_clocktime bct;
   
           clock_ts_to_bcd(ts, &bct, false);
           clock_dbgprint_bcd(dev, CLOCK_DBG_WRITE, &bct);
   
           mtx_lock(&atrtc_time_lock);
           mtx_lock_spin(&atrtc_lock);
   
           /* Disable RTC updates and interrupts.  */
           rtcout_locked(RTC_STATUSB, RTCSB_HALT | RTCSB_24HR);
   
           /* Write all the time registers. */
           rtcout_locked(RTC_SEC,   bct.sec);
           rtcout_locked(RTC_MIN,   bct.min);
           rtcout_locked(RTC_HRS,   bct.hour);
           rtcout_locked(RTC_WDAY,  bct.dow + 1);
           rtcout_locked(RTC_DAY,   bct.day);
           rtcout_locked(RTC_MONTH, bct.mon);
           rtcout_locked(RTC_YEAR,  bct.year & 0xff);
           if (rtc_century)
                   rtcout_locked(rtc_century, bct.year >> 8);
   
           /*
            * Re-enable RTC updates and interrupts.
            */
           rtcout_locked(RTC_STATUSB, rtc_statusb);
           rtcin_locked(RTC_INTR);
   
           mtx_unlock_spin(&atrtc_lock);
           mtx_unlock(&atrtc_time_lock);
   
           return (0);
   }
   
   static int
   atrtc_gettime(device_t dev, struct timespec *ts)
   {
           struct bcd_clocktime bct;
   
           /* Look if we have a RTC present and the time is valid */
           if (!(rtcin(RTC_STATUSD) & RTCSD_PWR)) {
                   device_printf(dev, "WARNING: Battery failure indication\n");
                   return (EINVAL);
           }
   
           /*
            * wait for time update to complete
            * If RTCSA_TUP is zero, we have at least 244us before next update.
            * This is fast enough on most hardware, but a refinement would be
            * to make sure that no more than 240us pass after we start reading,
            * and try again if so.
            */
           mtx_lock(&atrtc_time_lock);
           while (rtcin(RTC_STATUSA) & RTCSA_TUP)
                   continue;
           mtx_lock_spin(&atrtc_lock);
           bct.sec  = rtcin_locked(RTC_SEC);
           bct.min  = rtcin_locked(RTC_MIN);
           bct.hour = rtcin_locked(RTC_HRS);
           bct.day  = rtcin_locked(RTC_DAY);
           bct.mon  = rtcin_locked(RTC_MONTH);
           bct.year = rtcin_locked(RTC_YEAR);
           if (rtc_century)
                   bct.year |= rtcin_locked(rtc_century) << 8;
           mtx_unlock_spin(&atrtc_lock);
           mtx_unlock(&atrtc_time_lock);
           /* dow is unused in timespec conversion and we have no nsec info. */
           bct.dow  = 0;
           bct.nsec = 0;
           clock_dbgprint_bcd(dev, CLOCK_DBG_READ, &bct);
           return (clock_bcd_to_ts(&bct, ts, false));
   }
   
   static device_method_t atrtc_isa_methods[] = {
           /* Device interface */
           DEVMETHOD(device_probe,         atrtc_probe),
           DEVMETHOD(device_attach,        atrtc_isa_attach),
           DEVMETHOD(device_detach,        bus_generic_detach),
           DEVMETHOD(device_shutdown,      bus_generic_shutdown),
           DEVMETHOD(device_suspend,       bus_generic_suspend),
                   /* XXX stop statclock? */
           DEVMETHOD(device_resume,        atrtc_resume),
   
           /* clock interface */
           DEVMETHOD(clock_gettime,        atrtc_gettime),
           DEVMETHOD(clock_settime,        atrtc_settime),
           { 0, 0 }
   };
   
   static driver_t atrtc_isa_driver = {
           "atrtc",
           atrtc_isa_methods,
           sizeof(struct atrtc_softc),
   };
   
   #ifdef DEV_ACPI
   static device_method_t atrtc_acpi_methods[] = {
           /* Device interface */
           DEVMETHOD(device_probe,         atrtc_probe),
           DEVMETHOD(device_attach,        atrtc_acpi_attach),
           DEVMETHOD(device_detach,        atrtc_acpi_detach),
                   /* XXX stop statclock? */
           DEVMETHOD(device_resume,        atrtc_resume),
   
           /* clock interface */
           DEVMETHOD(clock_gettime,        atrtc_gettime),
           DEVMETHOD(clock_settime,        atrtc_settime),
           { 0, 0 }
   };
   
   static driver_t atrtc_acpi_driver = {
           "atrtc",
           atrtc_acpi_methods,
           sizeof(struct atrtc_softc),
   };
   #endif  /* DEV_ACPI */
   
   DRIVER_MODULE(atrtc, isa, atrtc_isa_driver, 0, 0);
   #ifdef DEV_ACPI
   DRIVER_MODULE(atrtc, acpi, atrtc_acpi_driver, 0, 0);
   #endif
   ISA_PNP_INFO(atrtc_ids);

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