FreeBSD/Linux Kernel Cross Reference
sys/dev/uart/uart_core.c

     /*-
      * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
      *
      * Copyright (c) 2003 Marcel Moolenaar
      * 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 ``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 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("$FreeBSD$");
    
    #include <sys/param.h>
    #include <sys/systm.h>
    #include <sys/bus.h>
    #include <sys/conf.h>
    #include <sys/cons.h>
    #include <sys/fcntl.h>
    #include <sys/interrupt.h>
    #include <sys/kdb.h>
    #include <sys/kernel.h>
    #include <sys/malloc.h>
    #include <sys/queue.h>
    #include <sys/reboot.h>
    #include <sys/sysctl.h>
    #include <machine/bus.h>
    #include <sys/rman.h>
    #include <machine/resource.h>
    #include <machine/stdarg.h>
    
    #include <dev/uart/uart.h>
    #include <dev/uart/uart_bus.h>
    #include <dev/uart/uart_cpu.h>
    #include <dev/uart/uart_ppstypes.h>
    
    #include "uart_if.h"
    
    devclass_t uart_devclass;
    const char uart_driver_name[] = "uart";
    
    SLIST_HEAD(uart_devinfo_list, uart_devinfo) uart_sysdevs =
        SLIST_HEAD_INITIALIZER(uart_sysdevs);
    
    static MALLOC_DEFINE(M_UART, "UART", "UART driver");
    
    #ifndef UART_POLL_FREQ
    #define UART_POLL_FREQ          50
    #endif
    static int uart_poll_freq = UART_POLL_FREQ;
    SYSCTL_INT(_debug, OID_AUTO, uart_poll_freq, CTLFLAG_RDTUN, &uart_poll_freq,
        0, "UART poll frequency");
    
    static int uart_force_poll;
    SYSCTL_INT(_debug, OID_AUTO, uart_force_poll, CTLFLAG_RDTUN, &uart_force_poll,
        0, "Force UART polling");
    
    static inline int
    uart_pps_mode_valid(int pps_mode)
    {
            int opt;
    
            switch(pps_mode & UART_PPS_SIGNAL_MASK) {
            case UART_PPS_DISABLED:
            case UART_PPS_CTS:
            case UART_PPS_DCD:
                    break;
            default:
                    return (false);
            }
    
            opt = pps_mode & UART_PPS_OPTION_MASK;
            if ((opt & ~(UART_PPS_INVERT_PULSE | UART_PPS_NARROW_PULSE)) != 0)
                    return (false);
    
            return (true);
    }
    
    static void
    uart_pps_print_mode(struct uart_softc *sc)
    {
   
           device_printf(sc->sc_dev, "PPS capture mode: ");
           switch(sc->sc_pps_mode & UART_PPS_SIGNAL_MASK) {
           case UART_PPS_DISABLED:
                   printf("disabled");
                   break;
           case UART_PPS_CTS:
                   printf("CTS");
                   break;
           case UART_PPS_DCD:
                   printf("DCD");
                   break;
           default:
                   printf("invalid");
                   break;
           }
           if (sc->sc_pps_mode & UART_PPS_INVERT_PULSE)
                   printf("-Inverted");
           if (sc->sc_pps_mode & UART_PPS_NARROW_PULSE)
                   printf("-NarrowPulse");
           printf("\n");
   }
   
   static int
   uart_pps_mode_sysctl(SYSCTL_HANDLER_ARGS)
   {
           struct uart_softc *sc;
           int err, tmp;
   
           sc = arg1;
           tmp = sc->sc_pps_mode;
           err = sysctl_handle_int(oidp, &tmp, 0, req);
           if (err != 0 || req->newptr == NULL)
                   return (err);
           if (!uart_pps_mode_valid(tmp))
                   return (EINVAL);
           sc->sc_pps_mode = tmp;
           return(0);
   }
   
   static void
   uart_pps_process(struct uart_softc *sc, int ser_sig)
   {
           sbintime_t now;
           int is_assert, pps_sig;
   
           /* Which signal is configured as PPS?  Early out if none. */
           switch(sc->sc_pps_mode & UART_PPS_SIGNAL_MASK) {
           case UART_PPS_CTS:
                   pps_sig = SER_CTS;
                   break;
           case UART_PPS_DCD:
                   pps_sig = SER_DCD;
                   break;
           default:
                   return;
           }
   
           /* Early out if there is no change in the signal configured as PPS. */
           if ((ser_sig & SER_DELTA(pps_sig)) == 0)
                   return;
   
           /*
            * In narrow-pulse mode we need to synthesize both capture and clear
            * events from a single "delta occurred" indication from the uart
            * hardware because the pulse width is too narrow to reliably detect
            * both edges.  However, when the pulse width is close to our interrupt
            * processing latency we might intermittantly catch both edges.  To
            * guard against generating spurious events when that happens, we use a
            * separate timer to ensure at least half a second elapses before we
            * generate another event.
            */
           pps_capture(&sc->sc_pps);
           if (sc->sc_pps_mode & UART_PPS_NARROW_PULSE) {
                   now = getsbinuptime();
                   if (now > sc->sc_pps_captime + 500 * SBT_1MS) {
                           sc->sc_pps_captime = now;
                           pps_event(&sc->sc_pps, PPS_CAPTUREASSERT);
                           pps_event(&sc->sc_pps, PPS_CAPTURECLEAR);
                   }
           } else  {
                   is_assert = ser_sig & pps_sig;
                   if (sc->sc_pps_mode & UART_PPS_INVERT_PULSE)
                           is_assert = !is_assert;
                   pps_event(&sc->sc_pps, is_assert ? PPS_CAPTUREASSERT :
                       PPS_CAPTURECLEAR);
           }
   }
   
   static void
   uart_pps_init(struct uart_softc *sc)
   {
           struct sysctl_ctx_list *ctx;
           struct sysctl_oid *tree;
   
           ctx = device_get_sysctl_ctx(sc->sc_dev);
           tree = device_get_sysctl_tree(sc->sc_dev);
   
           /*
            * The historical default for pps capture mode is either DCD or CTS,
            * depending on the UART_PPS_ON_CTS kernel option.  Start with that,
            * then try to fetch the tunable that overrides the mode for all uart
            * devices, then try to fetch the sysctl-tunable that overrides the mode
            * for one specific device.
            */
   #ifdef UART_PPS_ON_CTS
           sc->sc_pps_mode = UART_PPS_CTS;
   #else
           sc->sc_pps_mode = UART_PPS_DCD;
   #endif
           TUNABLE_INT_FETCH("hw.uart.pps_mode", &sc->sc_pps_mode);
           SYSCTL_ADD_PROC(ctx, SYSCTL_CHILDREN(tree), OID_AUTO, "pps_mode",
               CTLTYPE_INT | CTLFLAG_RWTUN | CTLFLAG_MPSAFE, sc, 0,
               uart_pps_mode_sysctl, "I", "pulse mode: 0/1/2=disabled/CTS/DCD; "
               "add 0x10 to invert, 0x20 for narrow pulse");
   
           if (!uart_pps_mode_valid(sc->sc_pps_mode)) {
                   device_printf(sc->sc_dev, 
                       "Invalid pps_mode 0x%02x configured; disabling PPS capture\n",
                       sc->sc_pps_mode);
                   sc->sc_pps_mode = UART_PPS_DISABLED;
           } else if (bootverbose) {
                   uart_pps_print_mode(sc);
           }
   
           sc->sc_pps.ppscap = PPS_CAPTUREBOTH;
           sc->sc_pps.driver_mtx = uart_tty_getlock(sc);
           sc->sc_pps.driver_abi = PPS_ABI_VERSION;
           pps_init_abi(&sc->sc_pps);
   }
   
   void
   uart_add_sysdev(struct uart_devinfo *di)
   {
           SLIST_INSERT_HEAD(&uart_sysdevs, di, next);
   }
   
   const char *
   uart_getname(struct uart_class *uc)
   {
           return ((uc != NULL) ? uc->name : NULL);
   }
   
   struct uart_ops *
   uart_getops(struct uart_class *uc)
   {
           return ((uc != NULL) ? uc->uc_ops : NULL);
   }
   
   int
   uart_getrange(struct uart_class *uc)
   {
           return ((uc != NULL) ? uc->uc_range : 0);
   }
   
   u_int
   uart_getregshift(struct uart_class *uc)
   {
           return ((uc != NULL) ? uc->uc_rshift : 0);
   }
   
   u_int
   uart_getregiowidth(struct uart_class *uc)
   {
           return ((uc != NULL) ? uc->uc_riowidth : 0);
   }
   
   /*
    * Schedule a soft interrupt. We do this on the 0 to !0 transition
    * of the TTY pending interrupt status.
    */
   void
   uart_sched_softih(struct uart_softc *sc, uint32_t ipend)
   {
           uint32_t new, old;
   
           do {
                   old = sc->sc_ttypend;
                   new = old | ipend;
           } while (!atomic_cmpset_32(&sc->sc_ttypend, old, new));
   
           if ((old & SER_INT_MASK) == 0)
                   swi_sched(sc->sc_softih, 0);
   }
   
   /*
    * A break condition has been detected. We treat the break condition as
    * a special case that should not happen during normal operation. When
    * the break condition is to be passed to higher levels in the form of
    * a NUL character, we really want the break to be in the right place in
    * the input stream. The overhead to achieve that is not in relation to
    * the exceptional nature of the break condition, so we permit ourselves
    * to be sloppy.
    */
   static __inline int
   uart_intr_break(void *arg)
   {
           struct uart_softc *sc = arg;
   
   #if defined(KDB)
           if (sc->sc_sysdev != NULL && sc->sc_sysdev->type == UART_DEV_CONSOLE) {
                   if (kdb_break())
                           return (0);
           }
   #endif
           if (sc->sc_opened)
                   uart_sched_softih(sc, SER_INT_BREAK);
           return (0);
   }
   
   /*
    * Handle a receiver overrun situation. We lost at least 1 byte in the
    * input stream and it's our job to contain the situation. We grab as
    * much of the data we can, but otherwise flush the receiver FIFO to
    * create some breathing room. The net effect is that we avoid the
    * overrun condition to happen for the next X characters, where X is
    * related to the FIFO size at the cost of losing data right away.
    * So, instead of having multiple overrun interrupts in close proximity
    * to each other and possibly pessimizing UART interrupt latency for
    * other UARTs in a multiport configuration, we create a longer segment
    * of missing characters by freeing up the FIFO.
    * Each overrun condition is marked in the input buffer by a token. The
    * token represents the loss of at least one, but possible more bytes in
    * the input stream.
    */
   static __inline int
   uart_intr_overrun(void *arg)
   {
           struct uart_softc *sc = arg;
   
           if (sc->sc_opened) {
                   UART_RECEIVE(sc);
                   if (uart_rx_put(sc, UART_STAT_OVERRUN))
                           sc->sc_rxbuf[sc->sc_rxput] = UART_STAT_OVERRUN;
                   uart_sched_softih(sc, SER_INT_RXREADY);
           }
           sc->sc_rxoverruns++;
           UART_FLUSH(sc, UART_FLUSH_RECEIVER);
           return (0);
   }
   
   /*
    * Received data ready.
    */
   static __inline int
   uart_intr_rxready(void *arg)
   {
           struct uart_softc *sc = arg;
           int rxp;
   
           rxp = sc->sc_rxput;
           UART_RECEIVE(sc);
   #if defined(KDB)
           if (sc->sc_sysdev != NULL && sc->sc_sysdev->type == UART_DEV_CONSOLE) {
                   while (rxp != sc->sc_rxput) {
                           kdb_alt_break(sc->sc_rxbuf[rxp++], &sc->sc_altbrk);
                           if (rxp == sc->sc_rxbufsz)
                                   rxp = 0;
                   }
           }
   #endif
           if (sc->sc_opened)
                   uart_sched_softih(sc, SER_INT_RXREADY);
           else
                   sc->sc_rxput = sc->sc_rxget;    /* Ignore received data. */
           return (1);
   }
   
   /*
    * Line or modem status change (OOB signalling).
    * We pass the signals to the software interrupt handler for further
    * processing. Note that we merge the delta bits, but set the state
    * bits. This is to avoid losing state transitions due to having more
    * than 1 hardware interrupt between software interrupts.
    */
   static __inline int
   uart_intr_sigchg(void *arg)
   {
           struct uart_softc *sc = arg;
           int new, old, sig;
   
           sig = UART_GETSIG(sc);
   
           /*
            * Time pulse counting support, invoked whenever the PPS parameters are
            * currently set to capture either edge of the signal.
            */
           if (sc->sc_pps.ppsparam.mode & PPS_CAPTUREBOTH) {
                   uart_pps_process(sc, sig);
           }
   
           /*
            * Keep track of signal changes, even when the device is not
            * opened. This allows us to inform upper layers about a
            * possible loss of DCD and thus the existence of a (possibly)
            * different connection when we have DCD back, during the time
            * that the device was closed.
            */
           do {
                   old = sc->sc_ttypend;
                   new = old & ~SER_MASK_STATE;
                   new |= sig & SER_INT_SIGMASK;
           } while (!atomic_cmpset_32(&sc->sc_ttypend, old, new));
   
           if (sc->sc_opened)
                   uart_sched_softih(sc, SER_INT_SIGCHG);
           return (1);
   }
   
   /*
    * The transmitter can accept more data.
    */
   static __inline int
   uart_intr_txidle(void *arg)
   {
           struct uart_softc *sc = arg;
   
           if (sc->sc_txbusy) {
                   sc->sc_txbusy = 0;
                   uart_sched_softih(sc, SER_INT_TXIDLE);
           }
           return (0);
   }
   
   static int
   uart_intr(void *arg)
   {
           struct uart_softc *sc = arg;
           int cnt, ipend, testintr;
   
           if (sc->sc_leaving)
                   return (FILTER_STRAY);
   
           cnt = 0;
           testintr = sc->sc_testintr;
           while ((!testintr || cnt < 20) && (ipend = UART_IPEND(sc)) != 0) {
                   cnt++;
                   if (ipend & SER_INT_OVERRUN)
                           uart_intr_overrun(sc);
                   if (ipend & SER_INT_BREAK)
                           uart_intr_break(sc);
                   if (ipend & SER_INT_RXREADY)
                           uart_intr_rxready(sc);
                   if (ipend & SER_INT_SIGCHG)
                           uart_intr_sigchg(sc);
                   if (ipend & SER_INT_TXIDLE)
                           uart_intr_txidle(sc);
           }
   
           if (sc->sc_polled) {
                   callout_reset(&sc->sc_timer, hz / uart_poll_freq,
                       (callout_func_t *)uart_intr, sc);
           }
   
           return ((cnt == 0) ? FILTER_STRAY :
               ((testintr && cnt == 20) ? FILTER_SCHEDULE_THREAD :
               FILTER_HANDLED));
   }
   
   serdev_intr_t *
   uart_bus_ihand(device_t dev, int ipend)
   {
   
           switch (ipend) {
           case SER_INT_BREAK:
                   return (uart_intr_break);
           case SER_INT_OVERRUN:
                   return (uart_intr_overrun);
           case SER_INT_RXREADY:
                   return (uart_intr_rxready);
           case SER_INT_SIGCHG:
                   return (uart_intr_sigchg);
           case SER_INT_TXIDLE:
                   return (uart_intr_txidle);
           }
           return (NULL);
   }
   
   int
   uart_bus_ipend(device_t dev)
   {
           struct uart_softc *sc;
   
           sc = device_get_softc(dev);
           return (UART_IPEND(sc));
   }
   
   int
   uart_bus_sysdev(device_t dev)
   {
           struct uart_softc *sc;
   
           sc = device_get_softc(dev);
           return ((sc->sc_sysdev != NULL) ? 1 : 0);
   }
   
   int
   uart_bus_probe(device_t dev, int regshft, int regiowidth, int rclk, int rid, int chan, int quirks)
   {
           struct uart_softc *sc;
           struct uart_devinfo *sysdev;
           int error;
   
           sc = device_get_softc(dev);
   
           /*
            * All uart_class references are weak. Check that the needed
            * class has been compiled-in. Fail if not.
            */
           if (sc->sc_class == NULL)
                   return (ENXIO);
   
           /*
            * Initialize the instance. Note that the instance (=softc) does
            * not necessarily match the hardware specific softc. We can't do
            * anything about it now, because we may not attach to the device.
            * Hardware drivers cannot use any of the class specific fields
            * while probing.
            */
           kobj_init((kobj_t)sc, (kobj_class_t)sc->sc_class);
           sc->sc_dev = dev;
           if (device_get_desc(dev) == NULL)
                   device_set_desc(dev, uart_getname(sc->sc_class));
   
           /*
            * Allocate the register resource. We assume that all UARTs have
            * a single register window in either I/O port space or memory
            * mapped I/O space. Any UART that needs multiple windows will
            * consequently not be supported by this driver as-is. We try I/O
            * port space first because that's the common case.
            */
           sc->sc_rrid = rid;
           sc->sc_rtype = SYS_RES_IOPORT;
           sc->sc_rres = bus_alloc_resource_any(dev, sc->sc_rtype, &sc->sc_rrid,
               RF_ACTIVE);
           if (sc->sc_rres == NULL) {
                   sc->sc_rrid = rid;
                   sc->sc_rtype = SYS_RES_MEMORY;
                   sc->sc_rres = bus_alloc_resource_any(dev, sc->sc_rtype,
                       &sc->sc_rrid, RF_ACTIVE);
                   if (sc->sc_rres == NULL)
                           return (ENXIO);
           }
   
           /*
            * Fill in the bus access structure and compare this device with
            * a possible console device and/or a debug port. We set the flags
            * in the softc so that the hardware dependent probe can adjust
            * accordingly. In general, you don't want to permanently disrupt
            * console I/O.
            */
           sc->sc_bas.bsh = rman_get_bushandle(sc->sc_rres);
           sc->sc_bas.bst = rman_get_bustag(sc->sc_rres);
           sc->sc_bas.chan = chan;
           sc->sc_bas.regshft = regshft;
           sc->sc_bas.regiowidth = regiowidth;
           sc->sc_bas.rclk = (rclk == 0) ? sc->sc_class->uc_rclk : rclk;
           sc->sc_bas.busy_detect = !!(quirks & UART_F_BUSY_DETECT);
   
           SLIST_FOREACH(sysdev, &uart_sysdevs, next) {
                   if (chan == sysdev->bas.chan &&
                       uart_cpu_eqres(&sc->sc_bas, &sysdev->bas)) {
                           /* XXX check if ops matches class. */
                           sc->sc_sysdev = sysdev;
                           sysdev->bas.rclk = sc->sc_bas.rclk;
                   }
           }
   
           error = UART_PROBE(sc);
           bus_release_resource(dev, sc->sc_rtype, sc->sc_rrid, sc->sc_rres);
           return ((error) ? error : BUS_PROBE_DEFAULT);
   }
   
   int
   uart_bus_attach(device_t dev)
   {
           struct uart_softc *sc, *sc0;
           const char *sep;
           int error, filt;
   
           /*
            * The sc_class field defines the type of UART we're going to work
            * with and thus the size of the softc. Replace the generic softc
            * with one that matches the UART now that we're certain we handle
            * the device.
            */
           sc0 = device_get_softc(dev);
           if (sc0->sc_class->size > device_get_driver(dev)->size) {
                   sc = malloc(sc0->sc_class->size, M_UART, M_WAITOK|M_ZERO);
                   bcopy(sc0, sc, sizeof(*sc));
                   device_set_softc(dev, sc);
           } else
                   sc = sc0;
   
           /*
            * Now that we know the softc for this device, connect the back
            * pointer from the sysdev for this device, if any
            */
           if (sc->sc_sysdev != NULL)
                   sc->sc_sysdev->sc = sc;
   
           /*
            * Protect ourselves against interrupts while we're not completely
            * finished attaching and initializing. We don't expect interrupts
            * until after UART_ATTACH(), though.
            */
           sc->sc_leaving = 1;
   
           mtx_init(&sc->sc_hwmtx_s, "uart_hwmtx", NULL, MTX_SPIN);
           if (sc->sc_hwmtx == NULL)
                   sc->sc_hwmtx = &sc->sc_hwmtx_s;
   
           /*
            * Re-allocate. We expect that the softc contains the information
            * collected by uart_bus_probe() intact.
            */
           sc->sc_rres = bus_alloc_resource_any(dev, sc->sc_rtype, &sc->sc_rrid,
               RF_ACTIVE);
           if (sc->sc_rres == NULL) {
                   mtx_destroy(&sc->sc_hwmtx_s);
                   return (ENXIO);
           }
           sc->sc_bas.bsh = rman_get_bushandle(sc->sc_rres);
           sc->sc_bas.bst = rman_get_bustag(sc->sc_rres);
   
           /*
            * Ensure there is room for at least three full FIFOs of data in the
            * receive buffer (handles the case of low-level drivers with huge
            * FIFOs), and also ensure that there is no less than the historical
            * size of 384 bytes (handles the typical small-FIFO case).
            */
           sc->sc_rxbufsz = MAX(384, sc->sc_rxfifosz * 3);
           sc->sc_rxbuf = malloc(sc->sc_rxbufsz * sizeof(*sc->sc_rxbuf),
               M_UART, M_WAITOK);
           sc->sc_txbuf = malloc(sc->sc_txfifosz * sizeof(*sc->sc_txbuf),
               M_UART, M_WAITOK);
   
           error = UART_ATTACH(sc);
           if (error)
                   goto fail;
   
           if (sc->sc_hwiflow || sc->sc_hwoflow) {
                   sep = "";
                   device_print_prettyname(dev);
                   if (sc->sc_hwiflow) {
                           printf("%sRTS iflow", sep);
                           sep = ", ";
                   }
                   if (sc->sc_hwoflow) {
                           printf("%sCTS oflow", sep);
                           sep = ", ";
                   }
                   printf("\n");
           }
   
           if (sc->sc_sysdev != NULL) {
                   if (sc->sc_sysdev->baudrate == 0) {
                           if (UART_IOCTL(sc, UART_IOCTL_BAUD,
                               (intptr_t)&sc->sc_sysdev->baudrate) != 0)
                                   sc->sc_sysdev->baudrate = -1;
                   }
                   switch (sc->sc_sysdev->type) {
                   case UART_DEV_CONSOLE:
                           device_printf(dev, "console");
                           break;
                   case UART_DEV_DBGPORT:
                           device_printf(dev, "debug port");
                           break;
                   case UART_DEV_KEYBOARD:
                           device_printf(dev, "keyboard");
                           break;
                   default:
                           device_printf(dev, "unknown system device");
                           break;
                   }
                   printf(" (%d,%c,%d,%d)\n", sc->sc_sysdev->baudrate,
                       "noems"[sc->sc_sysdev->parity], sc->sc_sysdev->databits,
                       sc->sc_sysdev->stopbits);
           }
   
           sc->sc_leaving = 0;
           sc->sc_testintr = 1;
           filt = uart_intr(sc);
           sc->sc_testintr = 0;
   
           /*
            * Don't use interrupts if we couldn't clear any pending interrupt
            * conditions. We may have broken H/W and polling is probably the
            * safest thing to do.
            */
           if (filt != FILTER_SCHEDULE_THREAD && !uart_force_poll) {
                   sc->sc_ires = bus_alloc_resource_any(dev, SYS_RES_IRQ,
                       &sc->sc_irid, RF_ACTIVE | RF_SHAREABLE);
           }
           if (sc->sc_ires != NULL) {
                   error = bus_setup_intr(dev, sc->sc_ires, INTR_TYPE_TTY,
                       uart_intr, NULL, sc, &sc->sc_icookie);
                   sc->sc_fastintr = (error == 0) ? 1 : 0;
   
                   if (!sc->sc_fastintr)
                           error = bus_setup_intr(dev, sc->sc_ires,
                               INTR_TYPE_TTY | INTR_MPSAFE, NULL,
                               (driver_intr_t *)uart_intr, sc, &sc->sc_icookie);
   
                   if (error) {
                           device_printf(dev, "could not activate interrupt\n");
                           bus_release_resource(dev, SYS_RES_IRQ, sc->sc_irid,
                               sc->sc_ires);
                           sc->sc_ires = NULL;
                   }
           }
           if (sc->sc_ires == NULL) {
                   /* No interrupt resource. Force polled mode. */
                   sc->sc_polled = 1;
                   callout_init(&sc->sc_timer, 1);
                   callout_reset(&sc->sc_timer, hz / uart_poll_freq,
                       (callout_func_t *)uart_intr, sc);
           }
   
           if (bootverbose && (sc->sc_fastintr || sc->sc_polled)) {
                   sep = "";
                   device_print_prettyname(dev);
                   if (sc->sc_fastintr) {
                           printf("%sfast interrupt", sep);
                           sep = ", ";
                   }
                   if (sc->sc_polled) {
                           printf("%spolled mode (%dHz)", sep, uart_poll_freq);
                           sep = ", ";
                   }
                   printf("\n");
           }
   
           if (sc->sc_sysdev != NULL && sc->sc_sysdev->attach != NULL) {
                   if ((error = sc->sc_sysdev->attach(sc)) != 0)
                           goto fail;
           } else {
                   if ((error = uart_tty_attach(sc)) != 0)
                           goto fail;
                   uart_pps_init(sc);
           }
   
           if (sc->sc_sysdev != NULL)
                   sc->sc_sysdev->hwmtx = sc->sc_hwmtx;
   
           if (sc->sc_rxfifosz > 1)
                   SYSCTL_ADD_INT(device_get_sysctl_ctx(dev),
                       SYSCTL_CHILDREN(device_get_sysctl_tree(dev)), OID_AUTO,
                       "rx_overruns", CTLFLAG_RD, &sc->sc_rxoverruns, 0,
                       "Receive overruns");
   
           return (0);
   
    fail:
           free(sc->sc_txbuf, M_UART);
           free(sc->sc_rxbuf, M_UART);
   
           if (sc->sc_ires != NULL) {
                   bus_teardown_intr(dev, sc->sc_ires, sc->sc_icookie);
                   bus_release_resource(dev, SYS_RES_IRQ, sc->sc_irid,
                       sc->sc_ires);
           }
           bus_release_resource(dev, sc->sc_rtype, sc->sc_rrid, sc->sc_rres);
   
           mtx_destroy(&sc->sc_hwmtx_s);
   
           return (error);
   }
   
   int
   uart_bus_detach(device_t dev)
   {
           struct uart_softc *sc;
   
           sc = device_get_softc(dev);
   
           sc->sc_leaving = 1;
   
           if (sc->sc_sysdev != NULL)
                   sc->sc_sysdev->hwmtx = NULL;
   
           UART_DETACH(sc);
   
           if (sc->sc_sysdev != NULL && sc->sc_sysdev->detach != NULL)
                   (*sc->sc_sysdev->detach)(sc);
           else
                   uart_tty_detach(sc);
   
           free(sc->sc_txbuf, M_UART);
           free(sc->sc_rxbuf, M_UART);
   
           if (sc->sc_ires != NULL) {
                   bus_teardown_intr(dev, sc->sc_ires, sc->sc_icookie);
                   bus_release_resource(dev, SYS_RES_IRQ, sc->sc_irid,
                       sc->sc_ires);
           }
           bus_release_resource(dev, sc->sc_rtype, sc->sc_rrid, sc->sc_rres);
   
           mtx_destroy(&sc->sc_hwmtx_s);
   
           if (sc->sc_class->size > device_get_driver(dev)->size) {
                   device_set_softc(dev, NULL);
                   free(sc, M_UART);
           }
   
           return (0);
   }
   
   int
   uart_bus_resume(device_t dev)
   {
           struct uart_softc *sc;
   
           sc = device_get_softc(dev);
           return (UART_ATTACH(sc));
   }
   
   void
   uart_grab(struct uart_devinfo *di)
   {
   
           if (di->sc)
                   UART_GRAB(di->sc);
   }
   
   void
   uart_ungrab(struct uart_devinfo *di)
   {
   
           if (di->sc)
                   UART_UNGRAB(di->sc);
   }

Cache object: 5f834f1d9f93e2cc7b257e69986b371f