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bus.c

/*
 *  linux/arch/arm/common/amba.c
 *
 *  Copyright (C) 2003 Deep Blue Solutions Ltd, All Rights Reserved.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */
#include <linux/module.h>
#include <linux/init.h>
#include <linux/device.h>
#include <linux/string.h>
#include <linux/slab.h>
#include <linux/amba/bus.h>

#include <asm/io.h>
#include <asm/sizes.h>

#define to_amba_device(d)     container_of(d, struct amba_device, dev)
#define to_amba_driver(d)     container_of(d, struct amba_driver, drv)

static struct amba_id *
amba_lookup(struct amba_id *table, struct amba_device *dev)
{
      int ret = 0;

      while (table->mask) {
            ret = (dev->periphid & table->mask) == table->id;
            if (ret)
                  break;
            table++;
      }

      return ret ? table : NULL;
}

static int amba_match(struct device *dev, struct device_driver *drv)
{
      struct amba_device *pcdev = to_amba_device(dev);
      struct amba_driver *pcdrv = to_amba_driver(drv);

      return amba_lookup(pcdrv->id_table, pcdev) != NULL;
}

#ifdef CONFIG_HOTPLUG
static int amba_uevent(struct device *dev, struct kobj_uevent_env *env)
{
      struct amba_device *pcdev = to_amba_device(dev);
      int retval = 0;

      retval = add_uevent_var(env, "AMBA_ID=%08x", pcdev->periphid);
      return retval;
}
#else
#define amba_uevent NULL
#endif

static int amba_suspend(struct device *dev, pm_message_t state)
{
      struct amba_driver *drv = to_amba_driver(dev->driver);
      int ret = 0;

      if (dev->driver && drv->suspend)
            ret = drv->suspend(to_amba_device(dev), state);
      return ret;
}

static int amba_resume(struct device *dev)
{
      struct amba_driver *drv = to_amba_driver(dev->driver);
      int ret = 0;

      if (dev->driver && drv->resume)
            ret = drv->resume(to_amba_device(dev));
      return ret;
}

#define amba_attr_func(name,fmt,arg...)                           \
static ssize_t name##_show(struct device *_dev,                   \
                     struct device_attribute *attr, char *buf)    \
{                                                     \
      struct amba_device *dev = to_amba_device(_dev);             \
      return sprintf(buf, fmt, arg);                              \
}

#define amba_attr(name,fmt,arg...)  \
amba_attr_func(name,fmt,arg)        \
static DEVICE_ATTR(name, S_IRUGO, name##_show, NULL)

amba_attr_func(id, "%08x\n", dev->periphid);
amba_attr(irq0, "%u\n", dev->irq[0]);
amba_attr(irq1, "%u\n", dev->irq[1]);
amba_attr_func(resource, "\t%016llx\t%016llx\t%016lx\n",
       (unsigned long long)dev->res.start, (unsigned long long)dev->res.end,
       dev->res.flags);

static struct device_attribute amba_dev_attrs[] = {
      __ATTR_RO(id),
      __ATTR_RO(resource),
      __ATTR_NULL,
};

/*
 * Primecells are part of the Advanced Microcontroller Bus Architecture,
 * so we call the bus "amba".
 */
static struct bus_type amba_bustype = {
      .name       = "amba",
      .dev_attrs  = amba_dev_attrs,
      .match            = amba_match,
      .uevent           = amba_uevent,
      .suspend    = amba_suspend,
      .resume           = amba_resume,
};

static int __init amba_init(void)
{
      return bus_register(&amba_bustype);
}

postcore_initcall(amba_init);

/*
 * These are the device model conversion veneers; they convert the
 * device model structures to our more specific structures.
 */
static int amba_probe(struct device *dev)
{
      struct amba_device *pcdev = to_amba_device(dev);
      struct amba_driver *pcdrv = to_amba_driver(dev->driver);
      struct amba_id *id;

      id = amba_lookup(pcdrv->id_table, pcdev);

      return pcdrv->probe(pcdev, id);
}

static int amba_remove(struct device *dev)
{
      struct amba_driver *drv = to_amba_driver(dev->driver);
      return drv->remove(to_amba_device(dev));
}

static void amba_shutdown(struct device *dev)
{
      struct amba_driver *drv = to_amba_driver(dev->driver);
      drv->shutdown(to_amba_device(dev));
}

/**
 *    amba_driver_register - register an AMBA device driver
 *    @drv: amba device driver structure
 *
 *    Register an AMBA device driver with the Linux device model
 *    core.  If devices pre-exist, the drivers probe function will
 *    be called.
 */
int amba_driver_register(struct amba_driver *drv)
{
      drv->drv.bus = &amba_bustype;

#define SETFN(fn) if (drv->fn) drv->drv.fn = amba_##fn
      SETFN(probe);
      SETFN(remove);
      SETFN(shutdown);

      return driver_register(&drv->drv);
}

/**
 *    amba_driver_unregister - remove an AMBA device driver
 *    @drv: AMBA device driver structure to remove
 *
 *    Unregister an AMBA device driver from the Linux device
 *    model.  The device model will call the drivers remove function
 *    for each device the device driver is currently handling.
 */
void amba_driver_unregister(struct amba_driver *drv)
{
      driver_unregister(&drv->drv);
}


static void amba_device_release(struct device *dev)
{
      struct amba_device *d = to_amba_device(dev);

      if (d->res.parent)
            release_resource(&d->res);
      kfree(d);
}

/**
 *    amba_device_register - register an AMBA device
 *    @dev: AMBA device to register
 *    @parent: parent memory resource
 *
 *    Setup the AMBA device, reading the cell ID if present.
 *    Claim the resource, and register the AMBA device with
 *    the Linux device manager.
 */
int amba_device_register(struct amba_device *dev, struct resource *parent)
{
      u32 pid, cid;
      void __iomem *tmp;
      int i, ret;

      dev->dev.release = amba_device_release;
      dev->dev.bus = &amba_bustype;
      dev->dev.dma_mask = &dev->dma_mask;
      dev->res.name = dev->dev.bus_id;

      if (!dev->dev.coherent_dma_mask && dev->dma_mask)
            dev_warn(&dev->dev, "coherent dma mask is unset\n");

      ret = request_resource(parent, &dev->res);
      if (ret)
            goto err_out;

      tmp = ioremap(dev->res.start, SZ_4K);
      if (!tmp) {
            ret = -ENOMEM;
            goto err_release;
      }

      for (pid = 0, i = 0; i < 4; i++)
            pid |= (readl(tmp + 0xfe0 + 4 * i) & 255) << (i * 8);
      for (cid = 0, i = 0; i < 4; i++)
            cid |= (readl(tmp + 0xff0 + 4 * i) & 255) << (i * 8);

      iounmap(tmp);

      if (cid == 0xb105f00d)
            dev->periphid = pid;

      if (!dev->periphid) {
            ret = -ENODEV;
            goto err_release;
      }

      ret = device_register(&dev->dev);
      if (ret)
            goto err_release;

      if (dev->irq[0] != NO_IRQ)
            ret = device_create_file(&dev->dev, &dev_attr_irq0);
      if (ret == 0 && dev->irq[1] != NO_IRQ)
            ret = device_create_file(&dev->dev, &dev_attr_irq1);
      if (ret == 0)
            return ret;

      device_unregister(&dev->dev);

 err_release:
      release_resource(&dev->res);
 err_out:
      return ret;
}

/**
 *    amba_device_unregister - unregister an AMBA device
 *    @dev: AMBA device to remove
 *
 *    Remove the specified AMBA device from the Linux device
 *    manager.  All files associated with this object will be
 *    destroyed, and device drivers notified that the device has
 *    been removed.  The AMBA device's resources including
 *    the amba_device structure will be freed once all
 *    references to it have been dropped.
 */
void amba_device_unregister(struct amba_device *dev)
{
      device_unregister(&dev->dev);
}


struct find_data {
      struct amba_device *dev;
      struct device *parent;
      const char *busid;
      unsigned int id;
      unsigned int mask;
};

static int amba_find_match(struct device *dev, void *data)
{
      struct find_data *d = data;
      struct amba_device *pcdev = to_amba_device(dev);
      int r;

      r = (pcdev->periphid & d->mask) == d->id;
      if (d->parent)
            r &= d->parent == dev->parent;
      if (d->busid)
            r &= strcmp(dev->bus_id, d->busid) == 0;

      if (r) {
            get_device(dev);
            d->dev = pcdev;
      }

      return r;
}

/**
 *    amba_find_device - locate an AMBA device given a bus id
 *    @busid: bus id for device (or NULL)
 *    @parent: parent device (or NULL)
 *    @id: peripheral ID (or 0)
 *    @mask: peripheral ID mask (or 0)
 *
 *    Return the AMBA device corresponding to the supplied parameters.
 *    If no device matches, returns NULL.
 *
 *    NOTE: When a valid device is found, its refcount is
 *    incremented, and must be decremented before the returned
 *    reference.
 */
struct amba_device *
amba_find_device(const char *busid, struct device *parent, unsigned int id,
             unsigned int mask)
{
      struct find_data data;

      data.dev = NULL;
      data.parent = parent;
      data.busid = busid;
      data.id = id;
      data.mask = mask;

      bus_for_each_dev(&amba_bustype, NULL, &data, amba_find_match);

      return data.dev;
}

/**
 *    amba_request_regions - request all mem regions associated with device
 *    @dev: amba_device structure for device
 *    @name: name, or NULL to use driver name
 */
int amba_request_regions(struct amba_device *dev, const char *name)
{
      int ret = 0;

      if (!name)
            name = dev->dev.driver->name;

      if (!request_mem_region(dev->res.start, SZ_4K, name))
            ret = -EBUSY;

      return ret;
}

/**
 *    amba_release_regions - release mem regions assoicated with device
 *    @dev: amba_device structure for device
 *
 *    Release regions claimed by a successful call to amba_request_regions.
 */
void amba_release_regions(struct amba_device *dev)
{
      release_mem_region(dev->res.start, SZ_4K);
}

EXPORT_SYMBOL(amba_driver_register);
EXPORT_SYMBOL(amba_driver_unregister);
EXPORT_SYMBOL(amba_device_register);
EXPORT_SYMBOL(amba_device_unregister);
EXPORT_SYMBOL(amba_find_device);
EXPORT_SYMBOL(amba_request_regions);
EXPORT_SYMBOL(amba_release_regions);

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