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kfd_pasid.c revision 1.2.6.2 
      1 /*	$NetBSD: kfd_pasid.c,v 1.2.6.2 2019/06/10 22:07:59 christos Exp $	*/
      2 
      3 /*
      4  * Copyright 2014 Advanced Micro Devices, Inc.
      5  *
      6  * Permission is hereby granted, free of charge, to any person obtaining a
      7  * copy of this software and associated documentation files (the "Software"),
      8  * to deal in the Software without restriction, including without limitation
      9  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
     10  * and/or sell copies of the Software, and to permit persons to whom the
     11  * Software is furnished to do so, subject to the following conditions:
     12  *
     13  * The above copyright notice and this permission notice shall be included in
     14  * all copies or substantial portions of the Software.
     15  *
     16  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
     17  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
     18  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
     19  * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
     20  * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
     21  * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
     22  * OTHER DEALINGS IN THE SOFTWARE.
     23  */
     24 
     25 #include <sys/cdefs.h>
     26 __KERNEL_RCSID(0, "$NetBSD: kfd_pasid.c,v 1.2.6.2 2019/06/10 22:07:59 christos Exp $");
     27 
     28 #include <linux/slab.h>
     29 #include <linux/types.h>
     30 #include "kfd_priv.h"
     31 
     32 static unsigned long *pasid_bitmap;
     33 static unsigned int pasid_limit;
     34 static DEFINE_MUTEX(pasid_mutex);
     35 
     36 int kfd_pasid_init(void)
     37 {
     38 	pasid_limit = KFD_MAX_NUM_OF_PROCESSES;
     39 
     40 	pasid_bitmap = kcalloc(BITS_TO_LONGS(pasid_limit), sizeof(long), GFP_KERNEL);
     41 	if (!pasid_bitmap)
     42 		return -ENOMEM;
     43 
     44 	set_bit(0, pasid_bitmap); /* PASID 0 is reserved. */
     45 
     46 	return 0;
     47 }
     48 
     49 void kfd_pasid_exit(void)
     50 {
     51 	kfree(pasid_bitmap);
     52 }
     53 
     54 bool kfd_set_pasid_limit(unsigned int new_limit)
     55 {
     56 	if (new_limit < pasid_limit) {
     57 		bool ok;
     58 
     59 		mutex_lock(&pasid_mutex);
     60 
     61 		/* ensure that no pasids >= new_limit are in-use */
     62 		ok = (find_next_bit(pasid_bitmap, pasid_limit, new_limit) ==
     63 								pasid_limit);
     64 		if (ok)
     65 			pasid_limit = new_limit;
     66 
     67 		mutex_unlock(&pasid_mutex);
     68 
     69 		return ok;
     70 	}
     71 
     72 	return true;
     73 }
     74 
     75 inline unsigned int kfd_get_pasid_limit(void)
     76 {
     77 	return pasid_limit;
     78 }
     79 
     80 unsigned int kfd_pasid_alloc(void)
     81 {
     82 	unsigned int found;
     83 
     84 	mutex_lock(&pasid_mutex);
     85 
     86 	found = find_first_zero_bit(pasid_bitmap, pasid_limit);
     87 	if (found == pasid_limit)
     88 		found = 0;
     89 	else
     90 		set_bit(found, pasid_bitmap);
     91 
     92 	mutex_unlock(&pasid_mutex);
     93 
     94 	return found;
     95 }
     96 
     97 void kfd_pasid_free(unsigned int pasid)
     98 {
     99 	BUG_ON(pasid == 0 || pasid >= pasid_limit);
    100 	clear_bit(pasid, pasid_bitmap);
    101 }
    102