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kernel/linux-rt-4.4.41/drivers/gpu/drm/amd/amdkfd/kfd_pasid.c 2.39 KB
5113f6f70   김현기   kernel add
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  /*
   * Copyright 2014 Advanced Micro Devices, Inc.
   *
   * Permission is hereby granted, free of charge, to any person obtaining a
   * copy of this software and associated documentation files (the "Software"),
   * to deal in the Software without restriction, including without limitation
   * the rights to use, copy, modify, merge, publish, distribute, sublicense,
   * and/or sell copies of the Software, and to permit persons to whom the
   * Software is furnished to do so, subject to the following conditions:
   *
   * The above copyright notice and this permission notice shall be included in
   * all copies or substantial portions of the Software.
   *
   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
   * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
   * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
   * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
   * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
   * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
   * OTHER DEALINGS IN THE SOFTWARE.
   */
  
  #include <linux/slab.h>
  #include <linux/types.h>
  #include "kfd_priv.h"
  
  static unsigned long *pasid_bitmap;
  static unsigned int pasid_limit;
  static DEFINE_MUTEX(pasid_mutex);
  
  int kfd_pasid_init(void)
  {
  	pasid_limit = KFD_MAX_NUM_OF_PROCESSES;
  
  	pasid_bitmap = kcalloc(BITS_TO_LONGS(pasid_limit), sizeof(long), GFP_KERNEL);
  	if (!pasid_bitmap)
  		return -ENOMEM;
  
  	set_bit(0, pasid_bitmap); /* PASID 0 is reserved. */
  
  	return 0;
  }
  
  void kfd_pasid_exit(void)
  {
  	kfree(pasid_bitmap);
  }
  
  bool kfd_set_pasid_limit(unsigned int new_limit)
  {
  	if (new_limit < pasid_limit) {
  		bool ok;
  
  		mutex_lock(&pasid_mutex);
  
  		/* ensure that no pasids >= new_limit are in-use */
  		ok = (find_next_bit(pasid_bitmap, pasid_limit, new_limit) ==
  								pasid_limit);
  		if (ok)
  			pasid_limit = new_limit;
  
  		mutex_unlock(&pasid_mutex);
  
  		return ok;
  	}
  
  	return true;
  }
  
  inline unsigned int kfd_get_pasid_limit(void)
  {
  	return pasid_limit;
  }
  
  unsigned int kfd_pasid_alloc(void)
  {
  	unsigned int found;
  
  	mutex_lock(&pasid_mutex);
  
  	found = find_first_zero_bit(pasid_bitmap, pasid_limit);
  	if (found == pasid_limit)
  		found = 0;
  	else
  		set_bit(found, pasid_bitmap);
  
  	mutex_unlock(&pasid_mutex);
  
  	return found;
  }
  
  void kfd_pasid_free(unsigned int pasid)
  {
  	BUG_ON(pasid == 0 || pasid >= pasid_limit);
  	clear_bit(pasid, pasid_bitmap);
  }