drivers/misc/mic/bus/mic_bus.c

   1 /*
   2  * Intel MIC Platform Software Stack (MPSS)
   3  *
   4  * Copyright(c) 2014 Intel Corporation.
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License, version 2, as
   8  * published by the Free Software Foundation.
   9  *
  10  * This program is distributed in the hope that it will be useful, but
  11  * WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  13  * General Public License for more details.
  14  *
  15  * The full GNU General Public License is included in this distribution in
  16  * the file called "COPYING".
  17  *
  18  * Intel MIC Bus driver.
  19  *
  20  * This implementation is very similar to the the virtio bus driver
  21  * implementation @ drivers/virtio/virtio.c
  22  */
  23 #include <linux/slab.h>
  24 #include <linux/module.h>
  25 #include <linux/idr.h>
  26 #include <linux/mic_bus.h>
  27
  28 /* Unique numbering for mbus devices. */
  29 static DEFINE_IDA(mbus_index_ida);
  30
  31 static ssize_t device_show(struct device *d,
  32                            struct device_attribute *attr, char *buf)
  33 {
  34         struct mbus_device *dev = dev_to_mbus(d);
  35         return sprintf(buf, "0x%04x\n", dev->id.device);
  36 }
  37 static DEVICE_ATTR_RO(device);
  38
  39 static ssize_t vendor_show(struct device *d,
  40                            struct device_attribute *attr, char *buf)
  41 {
  42         struct mbus_device *dev = dev_to_mbus(d);
  43         return sprintf(buf, "0x%04x\n", dev->id.vendor);
  44 }
  45 static DEVICE_ATTR_RO(vendor);
  46
  47 static ssize_t modalias_show(struct device *d,
  48                              struct device_attribute *attr, char *buf)
  49 {
  50         struct mbus_device *dev = dev_to_mbus(d);
  51         return sprintf(buf, "mbus:d%08Xv%08X\n",
  52                        dev->id.device, dev->id.vendor);
  53 }
  54 static DEVICE_ATTR_RO(modalias);
  55
  56 static struct attribute *mbus_dev_attrs[] = {
  57         &dev_attr_device.attr,
  58         &dev_attr_vendor.attr,
  59         &dev_attr_modalias.attr,
  60         NULL,
  61 };
  62 ATTRIBUTE_GROUPS(mbus_dev);
  63
  64 static inline int mbus_id_match(const struct mbus_device *dev,
  65                                 const struct mbus_device_id *id)
  66 {
  67         if (id->device != dev->id.device && id->device != MBUS_DEV_ANY_ID)
  68                 return 0;
  69
  70         return id->vendor == MBUS_DEV_ANY_ID || id->vendor == dev->id.vendor;
  71 }
  72
  73 /*
  74  * This looks through all the IDs a driver claims to support.  If any of them
  75  * match, we return 1 and the kernel will call mbus_dev_probe().
  76  */
  77 static int mbus_dev_match(struct device *dv, struct device_driver *dr)
  78 {
  79         unsigned int i;
  80         struct mbus_device *dev = dev_to_mbus(dv);
  81         const struct mbus_device_id *ids;
  82
  83         ids = drv_to_mbus(dr)->id_table;
  84         for (i = 0; ids[i].device; i++)
  85                 if (mbus_id_match(dev, &ids[i]))
  86                         return 1;
  87         return 0;
  88 }
  89
  90 static int mbus_uevent(struct device *dv, struct kobj_uevent_env *env)
  91 {
  92         struct mbus_device *dev = dev_to_mbus(dv);
  93
  94         return add_uevent_var(env, "MODALIAS=mbus:d%08Xv%08X",
  95                               dev->id.device, dev->id.vendor);
  96 }
  97
  98 static int mbus_dev_probe(struct device *d)
  99 {
 100         int err;
 101         struct mbus_device *dev = dev_to_mbus(d);
 102         struct mbus_driver *drv = drv_to_mbus(dev->dev.driver);
 103
 104         err = drv->probe(dev);
 105         if (!err)
 106                 if (drv->scan)
 107                         drv->scan(dev);
 108         return err;
 109 }
 110
 111 static int mbus_dev_remove(struct device *d)
 112 {
 113         struct mbus_device *dev = dev_to_mbus(d);
 114         struct mbus_driver *drv = drv_to_mbus(dev->dev.driver);
 115
 116         drv->remove(dev);
 117         return 0;
 118 }
 119
 120 static struct bus_type mic_bus = {
 121         .name  = "mic_bus",
 122         .match = mbus_dev_match,
 123         .dev_groups = mbus_dev_groups,
 124         .uevent = mbus_uevent,
 125         .probe = mbus_dev_probe,
 126         .remove = mbus_dev_remove,
 127 };
 128
 129 int mbus_register_driver(struct mbus_driver *driver)
 130 {
 131         driver->driver.bus = &mic_bus;
 132         return driver_register(&driver->driver);
 133 }
 134 EXPORT_SYMBOL_GPL(mbus_register_driver);
 135
 136 void mbus_unregister_driver(struct mbus_driver *driver)
 137 {
 138         driver_unregister(&driver->driver);
 139 }
 140 EXPORT_SYMBOL_GPL(mbus_unregister_driver);
 141
 142 static void mbus_release_dev(struct device *d)
 143 {
 144         struct mbus_device *mbdev = dev_to_mbus(d);
 145         kfree(mbdev);
 146 }
 147
 148 struct mbus_device *
 149 mbus_register_device(struct device *pdev, int id, struct dma_map_ops *dma_ops,
 150                      struct mbus_hw_ops *hw_ops, void __iomem *mmio_va)
 151 {
 152         int ret;
 153         struct mbus_device *mbdev;
 154
 155         mbdev = kzalloc(sizeof(*mbdev), GFP_KERNEL);
 156         if (!mbdev)
 157                 return ERR_PTR(-ENOMEM);
 158
 159         mbdev->mmio_va = mmio_va;
 160         mbdev->dev.parent = pdev;
 161         mbdev->id.device = id;
 162         mbdev->id.vendor = MBUS_DEV_ANY_ID;
 163         mbdev->dev.archdata.dma_ops = dma_ops;
 164         mbdev->dev.dma_mask = &mbdev->dev.coherent_dma_mask;
 165         dma_set_mask(&mbdev->dev, DMA_BIT_MASK(64));
 166         mbdev->dev.release = mbus_release_dev;
 167         mbdev->hw_ops = hw_ops;
 168         mbdev->dev.bus = &mic_bus;
 169
 170         /* Assign a unique device index and hence name. */
 171         ret = ida_simple_get(&mbus_index_ida, 0, 0, GFP_KERNEL);
 172         if (ret < 0)
 173                 goto free_mbdev;
 174
 175         mbdev->index = ret;
 176         dev_set_name(&mbdev->dev, "mbus-dev%u", mbdev->index);
 177         /*
 178          * device_register() causes the bus infrastructure to look for a
 179          * matching driver.
 180          */
 181         ret = device_register(&mbdev->dev);
 182         if (ret)
 183                 goto ida_remove;
 184         return mbdev;
 185 ida_remove:
 186         ida_simple_remove(&mbus_index_ida, mbdev->index);
 187 free_mbdev:
 188         kfree(mbdev);
 189         return ERR_PTR(ret);
 190 }
 191 EXPORT_SYMBOL_GPL(mbus_register_device);
 192
 193 void mbus_unregister_device(struct mbus_device *mbdev)
 194 {
 195         int index = mbdev->index; /* save for after device release */
 196
 197         device_unregister(&mbdev->dev);
 198         ida_simple_remove(&mbus_index_ida, index);
 199 }
 200 EXPORT_SYMBOL_GPL(mbus_unregister_device);
 201
 202 static int __init mbus_init(void)
 203 {
 204         return bus_register(&mic_bus);
 205 }
 206
 207 static void __exit mbus_exit(void)
 208 {
 209         bus_unregister(&mic_bus);
 210         ida_destroy(&mbus_index_ida);
 211 }
 212
 213 core_initcall(mbus_init);
 214 module_exit(mbus_exit);
 215
 216 MODULE_AUTHOR("Intel Corporation");
 217 MODULE_DESCRIPTION("Intel(R) MIC Bus driver");
 218 MODULE_LICENSE("GPL v2");