1 /****************************************************************************** 2 * Talks to Xen Store to figure out what devices we have. 3 * 4 * Copyright (C) 2009, 2010 Spectra Logic Corporation 5 * Copyright (C) 2008 Doug Rabson 6 * Copyright (C) 2005 Rusty Russell, IBM Corporation 7 * Copyright (C) 2005 Mike Wray, Hewlett-Packard 8 * Copyright (C) 2005 XenSource Ltd 9 * 10 * This file may be distributed separately from the Linux kernel, or 11 * incorporated into other software packages, subject to the following license: 12 * 13 * Permission is hereby granted, free of charge, to any person obtaining a copy 14 * of this source file (the "Software"), to deal in the Software without 15 * restriction, including without limitation the rights to use, copy, modify, 16 * merge, publish, distribute, sublicense, and/or sell copies of the Software, 17 * and to permit persons to whom the Software is furnished to do so, subject to 18 * the following conditions: 19 * 20 * The above copyright notice and this permission notice shall be included in 21 * all copies or substantial portions of the Software. 22 * 23 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 24 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 25 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE 26 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 27 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING 28 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS 29 * IN THE SOFTWARE. 30 */ 31 32 /** 33 * \file xenbusb_front.c 34 * 35 * XenBus management of the NewBus bus containing the frontend instances of 36 * Xen split devices. 37 */ 38 39 #include <sys/param.h> 40 #include <sys/bus.h> 41 #include <sys/kernel.h> 42 #include <sys/lock.h> 43 #include <sys/malloc.h> 44 #include <sys/module.h> 45 #include <sys/sbuf.h> 46 #include <sys/stdarg.h> 47 #include <sys/sysctl.h> 48 #include <sys/syslog.h> 49 #include <sys/systm.h> 50 #include <sys/sx.h> 51 #include <sys/taskqueue.h> 52 53 #include <xen/xen-os.h> 54 #include <xen/gnttab.h> 55 #include <xen/xenbus/xenbusvar.h> 56 #include <xen/xenbus/xenbusb.h> 57 58 /*------------------ Private Device Attachment Functions --------------------*/ 59 /** 60 * \brief Probe for the existence of the XenBus front bus. 61 * 62 * \param dev NewBus device_t for this XenBus front bus instance. 63 * 64 * \return Always returns 0 indicating success. 65 */ 66 static int 67 xenbusb_front_probe(device_t dev) 68 { 69 device_set_desc(dev, "Xen Frontend Devices"); 70 71 return (0); 72 } 73 74 /** 75 * \brief Attach the XenBus front bus. 76 * 77 * \param dev NewBus device_t for this XenBus front bus instance. 78 * 79 * \return On success, 0. Otherwise an errno value indicating the 80 * type of failure. 81 */ 82 static int 83 xenbusb_front_attach(device_t dev) 84 { 85 return (xenbusb_attach(dev, "device", /*id_components*/1)); 86 } 87 88 /** 89 * \brief Enumerate all devices of the given type on this bus. 90 * 91 * \param dev NewBus device_t for this XenBus front bus instance. 92 * \param type String indicating the device sub-tree (e.g. "vfb", "vif") 93 * to enumerate. 94 * 95 * \return On success, 0. Otherwise an errno value indicating the 96 * type of failure. 97 * 98 * Devices that are found are entered into the NewBus hierarchy via 99 * xenbusb_add_device(). xenbusb_add_device() ignores duplicate detects 100 * and ignores duplicate devices, so it can be called unconditionally 101 * for any device found in the XenStore. 102 */ 103 static int 104 xenbusb_front_enumerate_type(device_t dev, const char *type) 105 { 106 struct xenbusb_softc *xbs; 107 const char **dir; 108 unsigned int i, count; 109 int error; 110 111 xbs = device_get_softc(dev); 112 error = xs_directory(XST_NIL, xbs->xbs_node, type, &count, &dir); 113 if (error) 114 return (error); 115 for (i = 0; i < count; i++) 116 xenbusb_add_device(dev, type, dir[i]); 117 118 free(dir, M_XENSTORE); 119 120 return (0); 121 } 122 123 /** 124 * \brief Determine and store the XenStore path for the other end of 125 * a split device whose local end is represented by ivars. 126 * 127 * If successful, the xd_otherend_path field of the child's instance 128 * variables will be updated. 129 * 130 * \param dev NewBus device_t for this XenBus front bus instance. 131 * \param ivars Instance variables from the XenBus child device for 132 * which to perform this function. 133 * 134 * \return On success, 0. Otherwise an errno value indicating the 135 * type of failure. 136 */ 137 static int 138 xenbusb_front_get_otherend_node(device_t dev, struct xenbus_device_ivars *ivars) 139 { 140 char *otherend_path; 141 int error; 142 143 if (ivars->xd_otherend_path != NULL) { 144 free(ivars->xd_otherend_path, M_XENBUS); 145 ivars->xd_otherend_path = NULL; 146 } 147 148 error = xs_gather(XST_NIL, ivars->xd_node, 149 "backend-id", "%i", &ivars->xd_otherend_id, 150 "backend", NULL, &otherend_path, 151 NULL); 152 153 if (error == 0) { 154 ivars->xd_otherend_path = strdup(otherend_path, M_XENBUS); 155 ivars->xd_otherend_path_len = strlen(otherend_path); 156 free(otherend_path, M_XENSTORE); 157 } 158 return (error); 159 } 160 161 /*-------------------- Private Device Attachment Data -----------------------*/ 162 static device_method_t xenbusb_front_methods[] = { 163 /* Device interface */ 164 DEVMETHOD(device_identify, xenbusb_identify), 165 DEVMETHOD(device_probe, xenbusb_front_probe), 166 DEVMETHOD(device_attach, xenbusb_front_attach), 167 DEVMETHOD(device_detach, bus_generic_detach), 168 DEVMETHOD(device_shutdown, bus_generic_shutdown), 169 DEVMETHOD(device_suspend, bus_generic_suspend), 170 DEVMETHOD(device_resume, xenbusb_resume), 171 172 /* Bus Interface */ 173 DEVMETHOD(bus_print_child, xenbusb_print_child), 174 DEVMETHOD(bus_read_ivar, xenbusb_read_ivar), 175 DEVMETHOD(bus_write_ivar, xenbusb_write_ivar), 176 DEVMETHOD(bus_alloc_resource, bus_generic_alloc_resource), 177 DEVMETHOD(bus_release_resource, bus_generic_release_resource), 178 DEVMETHOD(bus_activate_resource, bus_generic_activate_resource), 179 DEVMETHOD(bus_deactivate_resource, bus_generic_deactivate_resource), 180 181 /* XenBus Bus Interface */ 182 DEVMETHOD(xenbusb_enumerate_type, xenbusb_front_enumerate_type), 183 DEVMETHOD(xenbusb_get_otherend_node, xenbusb_front_get_otherend_node), 184 185 DEVMETHOD_END 186 }; 187 188 DEFINE_CLASS_0(xenbusb_front, xenbusb_front_driver, xenbusb_front_methods, 189 sizeof(struct xenbusb_softc)); 190 191 DRIVER_MODULE(xenbusb_front, xenstore, xenbusb_front_driver, 0, 0); 192