drivers/uwb/umc-bus.c

   1 /*
   2  * Bus for UWB Multi-interface Controller capabilities.
   3  *
   4  * Copyright (C) 2007 Cambridge Silicon Radio Ltd.
   5  *
   6  * This file is released under the GNU GPL v2.
   7  */
   8 #include <linux/kernel.h>
   9 #include <linux/sysfs.h>
  10 #include <linux/workqueue.h>
  11 #include <linux/module.h>
  12 #include <linux/uwb/umc.h>
  13 #include <linux/pci.h>
  14
  15 static int umc_bus_pre_reset_helper(struct device *dev, void *data)
  16 {
  17         int ret = 0;
  18
  19         if (dev->driver) {
  20                 struct umc_dev *umc = to_umc_dev(dev);
  21                 struct umc_driver *umc_drv = to_umc_driver(dev->driver);
  22
  23                 if (umc_drv->pre_reset)
  24                         ret = umc_drv->pre_reset(umc);
  25                 else
  26                         device_release_driver(dev);
  27         }
  28         return ret;
  29 }
  30
  31 static int umc_bus_post_reset_helper(struct device *dev, void *data)
  32 {
  33         int ret = 0;
  34
  35         if (dev->driver) {
  36                 struct umc_dev *umc = to_umc_dev(dev);
  37                 struct umc_driver *umc_drv = to_umc_driver(dev->driver);
  38
  39                 if (umc_drv->post_reset)
  40                         ret = umc_drv->post_reset(umc);
  41         } else
  42                 ret = device_attach(dev);
  43
  44         return ret;
  45 }
  46
  47 /**
  48  * umc_controller_reset - reset the whole UMC controller
  49  * @umc: the UMC device for the radio controller.
  50  *
  51  * Drivers or all capabilities of the controller will have their
  52  * pre_reset methods called or be unbound from their device.  Then all
  53  * post_reset methods will be called or the drivers will be rebound.
  54  *
  55  * Radio controllers must provide pre_reset and post_reset methods and
  56  * reset the hardware in their start method.
  57  *
  58  * If this is called while a probe() or remove() is in progress it
  59  * will return -EAGAIN and not perform the reset.
  60  */
  61 int umc_controller_reset(struct umc_dev *umc)
  62 {
  63         struct device *parent = umc->dev.parent;
  64         int ret = 0;
  65
  66         if (!device_trylock(parent))
  67                 return -EAGAIN;
  68         ret = device_for_each_child(parent, parent, umc_bus_pre_reset_helper);
  69         if (ret >= 0)
  70                 ret = device_for_each_child(parent, parent, umc_bus_post_reset_helper);
  71         device_unlock(parent);
  72
  73         return ret;
  74 }
  75 EXPORT_SYMBOL_GPL(umc_controller_reset);
  76
  77 /**
  78  * umc_match_pci_id - match a UMC driver to a UMC device's parent PCI device.
  79  * @umc_drv: umc driver with match_data pointing to a zero-terminated
  80  * table of pci_device_id's.
  81  * @umc: umc device whose parent is to be matched.
  82  */
  83 int umc_match_pci_id(struct umc_driver *umc_drv, struct umc_dev *umc)
  84 {
  85         const struct pci_device_id *id_table = umc_drv->match_data;
  86         struct pci_dev *pci;
  87
  88         if (!dev_is_pci(umc->dev.parent))
  89                 return 0;
  90
  91         pci = to_pci_dev(umc->dev.parent);
  92         return pci_match_id(id_table, pci) != NULL;
  93 }
  94 EXPORT_SYMBOL_GPL(umc_match_pci_id);
  95
  96 static int umc_bus_rescan_helper(struct device *dev, void *data)
  97 {
  98         int ret = 0;
  99
 100         if (!dev->driver)
 101                 ret = device_attach(dev);
 102
 103         return ret;
 104 }
 105
 106 static void umc_bus_rescan(struct device *parent)
 107 {
 108         int err;
 109
 110         /*
 111          * We can't use bus_rescan_devices() here as it deadlocks when
 112          * it tries to retake the dev->parent semaphore.
 113          */
 114         err = device_for_each_child(parent, NULL, umc_bus_rescan_helper);
 115         if (err < 0)
 116                 printk(KERN_WARNING "%s: rescan of bus failed: %d\n",
 117                        KBUILD_MODNAME, err);
 118 }
 119
 120 static int umc_bus_match(struct device *dev, struct device_driver *drv)
 121 {
 122         struct umc_dev *umc = to_umc_dev(dev);
 123         struct umc_driver *umc_driver = to_umc_driver(drv);
 124
 125         if (umc->cap_id == umc_driver->cap_id) {
 126                 if (umc_driver->match)
 127                         return umc_driver->match(umc_driver, umc);
 128                 else
 129                         return 1;
 130         }
 131         return 0;
 132 }
 133
 134 static int umc_device_probe(struct device *dev)
 135 {
 136         struct umc_dev *umc;
 137         struct umc_driver *umc_driver;
 138         int err;
 139
 140         umc_driver = to_umc_driver(dev->driver);
 141         umc = to_umc_dev(dev);
 142
 143         get_device(dev);
 144         err = umc_driver->probe(umc);
 145         if (err)
 146                 put_device(dev);
 147         else
 148                 umc_bus_rescan(dev->parent);
 149
 150         return err;
 151 }
 152
 153 static int umc_device_remove(struct device *dev)
 154 {
 155         struct umc_dev *umc;
 156         struct umc_driver *umc_driver;
 157
 158         umc_driver = to_umc_driver(dev->driver);
 159         umc = to_umc_dev(dev);
 160
 161         umc_driver->remove(umc);
 162         put_device(dev);
 163         return 0;
 164 }
 165
 166 static ssize_t capability_id_show(struct device *dev, struct device_attribute *attr, char *buf)
 167 {
 168         struct umc_dev *umc = to_umc_dev(dev);
 169
 170         return sprintf(buf, "0x%02x\n", umc->cap_id);
 171 }
 172 static DEVICE_ATTR_RO(capability_id);
 173
 174 static ssize_t version_show(struct device *dev, struct device_attribute *attr, char *buf)
 175 {
 176         struct umc_dev *umc = to_umc_dev(dev);
 177
 178         return sprintf(buf, "0x%04x\n", umc->version);
 179 }
 180 static DEVICE_ATTR_RO(version);
 181
 182 static struct attribute *umc_dev_attrs[] = {
 183         &dev_attr_capability_id.attr,
 184         &dev_attr_version.attr,
 185         NULL,
 186 };
 187 ATTRIBUTE_GROUPS(umc_dev);
 188
 189 struct bus_type umc_bus_type = {
 190         .name           = "umc",
 191         .match          = umc_bus_match,
 192         .probe          = umc_device_probe,
 193         .remove         = umc_device_remove,
 194         .dev_groups     = umc_dev_groups,
 195 };
 196 EXPORT_SYMBOL_GPL(umc_bus_type);
 197
 198 static int __init umc_bus_init(void)
 199 {
 200         return bus_register(&umc_bus_type);
 201 }
 202 module_init(umc_bus_init);
 203
 204 static void __exit umc_bus_exit(void)
 205 {
 206         bus_unregister(&umc_bus_type);
 207 }
 208 module_exit(umc_bus_exit);
 209
 210 MODULE_DESCRIPTION("UWB Multi-interface Controller capability bus");
 211 MODULE_AUTHOR("Cambridge Silicon Radio Ltd.");
 212 MODULE_LICENSE("GPL");