FreeBSD/Linux Kernel Cross Reference
sys/xen/xenbus/xenbusb_front.c

     /******************************************************************************
      * Talks to Xen Store to figure out what devices we have.
      *
      * Copyright (C) 2009, 2010 Spectra Logic Corporation
      * Copyright (C) 2008 Doug Rabson
      * Copyright (C) 2005 Rusty Russell, IBM Corporation
      * Copyright (C) 2005 Mike Wray, Hewlett-Packard
      * Copyright (C) 2005 XenSource Ltd
      * 
     * This file may be distributed separately from the Linux kernel, or
     * incorporated into other software packages, subject to the following license:
     * 
     * Permission is hereby granted, free of charge, to any person obtaining a copy
     * of this source file (the "Software"), to deal in the Software without
     * restriction, including without limitation the rights to use, copy, modify,
     * merge, publish, distribute, sublicense, and/or sell copies of the Software,
     * and to permit persons to whom the Software is furnished to do so, subject to
     * the following conditions:
     * 
     * The above copyright notice and this permission notice shall be included in
     * all copies or substantial portions of the Software.
     * 
     * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
     * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
     * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
     * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
     * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
     * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
     * IN THE SOFTWARE.
     */
    
    /**
     * \file xenbusb_front.c
     *
     * XenBus management of the NewBus bus containing the frontend instances of
     * Xen split devices.
     */
    #include <sys/cdefs.h>
    __FBSDID("$FreeBSD: releng/12.0/sys/xen/xenbus/xenbusb_front.c 255040 2013-08-29 19:52:18Z gibbs $");
    
    #include <sys/param.h>
    #include <sys/bus.h>
    #include <sys/kernel.h>
    #include <sys/lock.h>
    #include <sys/malloc.h>
    #include <sys/module.h>
    #include <sys/sbuf.h>
    #include <sys/sysctl.h>
    #include <sys/syslog.h>
    #include <sys/systm.h>
    #include <sys/sx.h>
    #include <sys/taskqueue.h>
    
    #include <machine/stdarg.h>
    
    #include <xen/xen-os.h>
    #include <xen/gnttab.h>
    #include <xen/xenbus/xenbusvar.h>
    #include <xen/xenbus/xenbusb.h>
    
    
    /*------------------ Private Device Attachment Functions  --------------------*/
    /**
     * \brief Probe for the existance of the XenBus front bus.
     *
     * \param dev  NewBus device_t for this XenBus front bus instance.
     *
     * \return  Always returns 0 indicating success.
     */
    static int 
    xenbusb_front_probe(device_t dev)
    {
            device_set_desc(dev, "Xen Frontend Devices");
    
            return (0);
    }
    
    /**
     * \brief Attach the XenBus front bus.
     *
     * \param dev  NewBus device_t for this XenBus front bus instance.
     *
     * \return  On success, 0. Otherwise an errno value indicating the
     *          type of failure.
     */
    static int
    xenbusb_front_attach(device_t dev)
    {
            return (xenbusb_attach(dev, "device", /*id_components*/1));
    }
    
    /**
     * \brief Enumerate all devices of the given type on this bus.
     *
     * \param dev   NewBus device_t for this XenBus front bus instance.
     * \param type  String indicating the device sub-tree (e.g. "vfb", "vif")
     *              to enumerate. 
     *
     * \return  On success, 0. Otherwise an errno value indicating the
    *          type of failure.
    *
    * Devices that are found are entered into the NewBus hierarchy via
    * xenbusb_add_device().  xenbusb_add_device() ignores duplicate detects
    * and ignores duplicate devices, so it can be called unconditionally
    * for any device found in the XenStore.
    */
   static int
   xenbusb_front_enumerate_type(device_t dev, const char *type)
   {
           struct xenbusb_softc *xbs;
           const char **dir;
           unsigned int i, count;
           int error;
   
           xbs = device_get_softc(dev);
           error = xs_directory(XST_NIL, xbs->xbs_node, type, &count, &dir);
           if (error)
                   return (error);
           for (i = 0; i < count; i++)
                   xenbusb_add_device(dev, type, dir[i]);
   
           free(dir, M_XENSTORE);
   
           return (0);
   }
   
   /**
    * \brief Determine and store the XenStore path for the other end of
    *        a split device whose local end is represented by ivars.
    *
    * If successful, the xd_otherend_path field of the child's instance
    * variables will be updated.
    *
    * \param dev    NewBus device_t for this XenBus front bus instance.
    * \param ivars  Instance variables from the XenBus child device for
    *               which to perform this function.
    *
    * \return  On success, 0. Otherwise an errno value indicating the
    *          type of failure.
    */
   static int
   xenbusb_front_get_otherend_node(device_t dev, struct xenbus_device_ivars *ivars)
   {
           char *otherend_path;
           int error;
   
           if (ivars->xd_otherend_path != NULL) {
                   free(ivars->xd_otherend_path, M_XENBUS);
                   ivars->xd_otherend_path = NULL;
           }
                   
           error = xs_gather(XST_NIL, ivars->xd_node,
               "backend-id", "%i", &ivars->xd_otherend_id,
               "backend", NULL, &otherend_path,
               NULL);
   
           if (error == 0) {
                   ivars->xd_otherend_path = strdup(otherend_path, M_XENBUS);
                   ivars->xd_otherend_path_len = strlen(otherend_path);
                   free(otherend_path, M_XENSTORE);
           }
           return (error);
   }
   
   /*-------------------- Private Device Attachment Data  -----------------------*/
   static device_method_t xenbusb_front_methods[] = { 
           /* Device interface */ 
           DEVMETHOD(device_identify,      xenbusb_identify),
           DEVMETHOD(device_probe,         xenbusb_front_probe), 
           DEVMETHOD(device_attach,        xenbusb_front_attach), 
           DEVMETHOD(device_detach,        bus_generic_detach), 
           DEVMETHOD(device_shutdown,      bus_generic_shutdown), 
           DEVMETHOD(device_suspend,       bus_generic_suspend), 
           DEVMETHOD(device_resume,        xenbusb_resume), 
    
           /* Bus Interface */ 
           DEVMETHOD(bus_print_child,      xenbusb_print_child),
           DEVMETHOD(bus_read_ivar,        xenbusb_read_ivar), 
           DEVMETHOD(bus_write_ivar,       xenbusb_write_ivar), 
           DEVMETHOD(bus_alloc_resource,   bus_generic_alloc_resource),
           DEVMETHOD(bus_release_resource, bus_generic_release_resource),
           DEVMETHOD(bus_activate_resource, bus_generic_activate_resource),
           DEVMETHOD(bus_deactivate_resource, bus_generic_deactivate_resource),
    
           /* XenBus Bus Interface */
           DEVMETHOD(xenbusb_enumerate_type, xenbusb_front_enumerate_type),
           DEVMETHOD(xenbusb_get_otherend_node, xenbusb_front_get_otherend_node),
           { 0, 0 } 
   }; 
   
   DEFINE_CLASS_0(xenbusb_front, xenbusb_front_driver, xenbusb_front_methods,
                  sizeof(struct xenbusb_softc));
   devclass_t xenbusb_front_devclass; 
    
   DRIVER_MODULE(xenbusb_front, xenstore, xenbusb_front_driver,
                 xenbusb_front_devclass, 0, 0);

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