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/uwb/umc.h>
  12 #include <linux/pci.h>
  13
  14 static int umc_bus_pre_reset_helper(struct device *dev, void *data)
  15 {
  16         int ret = 0;
  17
  18         if (dev->driver) {
  19                 struct umc_dev *umc = to_umc_dev(dev);
  20                 struct umc_driver *umc_drv = to_umc_driver(dev->driver);
  21
  22                 if (umc_drv->pre_reset)
  23                         ret = umc_drv->pre_reset(umc);
  24                 else
  25                         device_release_driver(dev);
  26         }
  27         return ret;
  28 }
  29
  30 static int umc_bus_post_reset_helper(struct device *dev, void *data)
  31 {
  32         int ret = 0;
  33
  34         if (dev->driver) {
  35                 struct umc_dev *umc = to_umc_dev(dev);
  36                 struct umc_driver *umc_drv = to_umc_driver(dev->driver);
  37
  38                 if (umc_drv->post_reset)
  39                         ret = umc_drv->post_reset(umc);
  40         } else
  41                 ret = device_attach(dev);
  42
  43         return ret;
  44 }
  45
  46 /**
  47  * umc_controller_reset - reset the whole UMC controller
  48  * @umc: the UMC device for the radio controller.
  49  *
  50  * Drivers or all capabilities of the controller will have their
  51  * pre_reset methods called or be unbound from their device.  Then all
  52  * post_reset methods will be called or the drivers will be rebound.
  53  *
  54  * Radio controllers must provide pre_reset and post_reset methods and
  55  * reset the hardware in their start method.
  56  *
  57  * If this is called while a probe() or remove() is in progress it
  58  * will return -EAGAIN and not perform the reset.
  59  */
  60 int umc_controller_reset(struct umc_dev *umc)
  61 {
  62         struct device *parent = umc->dev.parent;
  63         int ret = 0;
  64
  65         if(down_trylock(&parent->sem))
  66                 return -EAGAIN;
  67         ret = device_for_each_child(parent, parent, umc_bus_pre_reset_helper);
  68         if (ret >= 0)
  69                 device_for_each_child(parent, parent, umc_bus_post_reset_helper);
  70         up(&parent->sem);
  71
  72         return ret;
  73 }
  74 EXPORT_SYMBOL_GPL(umc_controller_reset);
  75
  76 /**
  77  * umc_match_pci_id - match a UMC driver to a UMC device's parent PCI device.
  78  * @umc_drv: umc driver with match_data pointing to a zero-terminated
  79  * table of pci_device_id's.
  80  * @umc: umc device whose parent is to be matched.
  81  */
  82 int umc_match_pci_id(struct umc_driver *umc_drv, struct umc_dev *umc)
  83 {
  84         const struct pci_device_id *id_table = umc_drv->match_data;
  85         struct pci_dev *pci;
  86
  87         if (umc->dev.parent->bus != &pci_bus_type)
  88                 return 0;
  89
  90         pci = to_pci_dev(umc->dev.parent);
  91         return pci_match_id(id_table, pci) != NULL;
  92 }
  93 EXPORT_SYMBOL_GPL(umc_match_pci_id);
  94
  95 static int umc_bus_rescan_helper(struct device *dev, void *data)
  96 {
  97         int ret = 0;
  98
  99         if (!dev->driver)
 100                 ret = device_attach(dev);
 101
 102         return ret;
 103 }
 104
 105 static void umc_bus_rescan(struct device *parent)
 106 {
 107         int err;
 108
 109         /*
 110          * We can't use bus_rescan_devices() here as it deadlocks when
 111          * it tries to retake the dev->parent semaphore.
 112          */
 113         err = device_for_each_child(parent, NULL, umc_bus_rescan_helper);
 114         if (err < 0)
 115                 printk(KERN_WARNING "%s: rescan of bus failed: %d\n",
 116                        KBUILD_MODNAME, err);
 117 }
 118
 119 static int umc_bus_match(struct device *dev, struct device_driver *drv)
 120 {
 121         struct umc_dev *umc = to_umc_dev(dev);
 122         struct umc_driver *umc_driver = to_umc_driver(drv);
 123
 124         if (umc->cap_id == umc_driver->cap_id) {
 125                 if (umc_driver->match)
 126                         return umc_driver->match(umc_driver, umc);
 127                 else
 128                         return 1;
 129         }
 130         return 0;
 131 }
 132
 133 static int umc_device_probe(struct device *dev)
 134 {
 135         struct umc_dev *umc;
 136         struct umc_driver *umc_driver;
 137         int err;
 138
 139         umc_driver = to_umc_driver(dev->driver);
 140         umc = to_umc_dev(dev);
 141
 142         get_device(dev);
 143         err = umc_driver->probe(umc);
 144         if (err)
 145                 put_device(dev);
 146         else
 147                 umc_bus_rescan(dev->parent);
 148
 149         return err;
 150 }
 151
 152 static int umc_device_remove(struct device *dev)
 153 {
 154         struct umc_dev *umc;
 155         struct umc_driver *umc_driver;
 156
 157         umc_driver = to_umc_driver(dev->driver);
 158         umc = to_umc_dev(dev);
 159
 160         umc_driver->remove(umc);
 161         put_device(dev);
 162         return 0;
 163 }
 164
 165 static int umc_device_suspend(struct device *dev, pm_message_t state)
 166 {
 167         struct umc_dev *umc;
 168         struct umc_driver *umc_driver;
 169         int err = 0;
 170
 171         umc = to_umc_dev(dev);
 172
 173         if (dev->driver) {
 174                 umc_driver = to_umc_driver(dev->driver);
 175                 if (umc_driver->suspend)
 176                         err = umc_driver->suspend(umc, state);
 177         }
 178         return err;
 179 }
 180
 181 static int umc_device_resume(struct device *dev)
 182 {
 183         struct umc_dev *umc;
 184         struct umc_driver *umc_driver;
 185         int err = 0;
 186
 187         umc = to_umc_dev(dev);
 188
 189         if (dev->driver) {
 190                 umc_driver = to_umc_driver(dev->driver);
 191                 if (umc_driver->resume)
 192                         err = umc_driver->resume(umc);
 193         }
 194         return err;
 195 }
 196
 197 static ssize_t capability_id_show(struct device *dev, struct device_attribute *attr, char *buf)
 198 {
 199         struct umc_dev *umc = to_umc_dev(dev);
 200
 201         return sprintf(buf, "0x%02x\n", umc->cap_id);
 202 }
 203
 204 static ssize_t version_show(struct device *dev, struct device_attribute *attr, char *buf)
 205 {
 206         struct umc_dev *umc = to_umc_dev(dev);
 207
 208         return sprintf(buf, "0x%04x\n", umc->version);
 209 }
 210
 211 static struct device_attribute umc_dev_attrs[] = {
 212         __ATTR_RO(capability_id),
 213         __ATTR_RO(version),
 214         __ATTR_NULL,
 215 };
 216
 217 struct bus_type umc_bus_type = {
 218         .name           = "umc",
 219         .match          = umc_bus_match,
 220         .probe          = umc_device_probe,
 221         .remove         = umc_device_remove,
 222         .suspend        = umc_device_suspend,
 223         .resume         = umc_device_resume,
 224         .dev_attrs      = umc_dev_attrs,
 225 };
 226 EXPORT_SYMBOL_GPL(umc_bus_type);
 227
 228 static int __init umc_bus_init(void)
 229 {
 230         return bus_register(&umc_bus_type);
 231 }
 232 module_init(umc_bus_init);
 233
 234 static void __exit umc_bus_exit(void)
 235 {
 236         bus_unregister(&umc_bus_type);
 237 }
 238 module_exit(umc_bus_exit);
 239
 240 MODULE_DESCRIPTION("UWB Multi-interface Controller capability bus");
 241 MODULE_AUTHOR("Cambridge Silicon Radio Ltd.");
 242 MODULE_LICENSE("GPL");