text: /*
   * common EDAC components that must be in kernel
   *
   * Author: Dave Jiang <djiang@mvista.com>
   *
   * 2007 (c) MontaVista Software, Inc.
   * 2010 (c) Advanced Micro Devices Inc.
   *	    Borislav Petkov <bp@alien8.de>
   *
   * This file is licensed under the terms of the GNU General Public
   * License version 2. This program is licensed "as is" without any
   * warranty of any kind, whether express or implied.
   *
   */
  #include <linux/module.h>
  #include <linux/edac.h>
  #include <linux/atomic.h>
  #include <linux/device.h>
  #include <asm/edac.h>
  
  int edac_op_state = EDAC_OPSTATE_INVAL;
  EXPORT_SYMBOL_GPL(edac_op_state);
  
  atomic_t edac_handlers = ATOMIC_INIT(0);
  EXPORT_SYMBOL_GPL(edac_handlers);
  
  int edac_err_assert = 0;
  EXPORT_SYMBOL_GPL(edac_err_assert);
  
  static atomic_t edac_subsys_valid = ATOMIC_INIT(0);
  
  /*
   * called to determine if there is an EDAC driver interested in
   * knowing an event (such as NMI) occurred
   */
  int edac_handler_set(void)
  {
  	if (edac_op_state == EDAC_OPSTATE_POLL)
  		return 0;
  
  	return atomic_read(&edac_handlers);
  }
  EXPORT_SYMBOL_GPL(edac_handler_set);
  
  /*
   * handler for NMI type of interrupts to assert error
   */
  void edac_atomic_assert_error(void)
  {
  	edac_err_assert++;
  }
  EXPORT_SYMBOL_GPL(edac_atomic_assert_error);
  
  /*
   * sysfs object: /sys/devices/system/edac
   *	need to export to other files
   */
  struct bus_type edac_subsys = {
  	.name = "edac",
  	.dev_name = "edac",
  };
  EXPORT_SYMBOL_GPL(edac_subsys);
  
  /* return pointer to the 'edac' node in sysfs */
  struct bus_type *edac_get_sysfs_subsys(void)
  {
  	int err = 0;
  
  	if (atomic_read(&edac_subsys_valid))
  		goto out;
  
  	/* create the /sys/devices/system/edac directory */
  	err = subsys_system_register(&edac_subsys, NULL);
  	if (err) {
  		printk(KERN_ERR "Error registering toplevel EDAC sysfs dir\n");
  		return NULL;
  	}
  
  out:
  	atomic_inc(&edac_subsys_valid);
  	return &edac_subsys;
  }
  EXPORT_SYMBOL_GPL(edac_get_sysfs_subsys);
  
  void edac_put_sysfs_subsys(void)
  {
  	/* last user unregisters it */
  	if (atomic_dec_and_test(&edac_subsys_valid))
  		bus_unregister(&edac_subsys);
  }
  EXPORT_SYMBOL_GPL(edac_put_sysfs_subsys);
  