1 /*
2  * Copyright 2014 Advanced Micro Devices, Inc.
3  *
4  * Permission is hereby granted, free of charge, to any person obtaining a
5  * copy of this software and associated documentation files (the "Software"),
6  * to deal in the Software without restriction, including without limitation
7  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
8  * and/or sell copies of the Software, and to permit persons to whom the
9  * Software is furnished to do so, subject to the following conditions:
10  *
11  * The above copyright notice and this permission notice shall be included in
12  * all copies or substantial portions of the Software.
13  *
14  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
15  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
16  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
17  * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
18  * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
19  * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
20  * OTHER DEALINGS IN THE SOFTWARE.
21  */
22 
23 #include <linux/types.h>
24 #include "kfd_priv.h"
25 
26 static unsigned int pasid_bits = 16;
27 static const struct kfd2kgd_calls *kfd2kgd;
28 
29 bool kfd_set_pasid_limit(unsigned int new_limit)
30 {
31 	if (new_limit < 2)
32 		return false;
33 
34 	if (new_limit < (1U << pasid_bits)) {
35 		if (kfd2kgd)
36 			/* We've already allocated user PASIDs, too late to
37 			 * change the limit
38 			 */
39 			return false;
40 
41 		while (new_limit < (1U << pasid_bits))
42 			pasid_bits--;
43 	}
44 
45 	return true;
46 }
47 
48 unsigned int kfd_get_pasid_limit(void)
49 {
50 	return 1U << pasid_bits;
51 }
52 
53 unsigned int kfd_pasid_alloc(void)
54 {
55 	int r;
56 
57 	/* Find the first best KFD device for calling KGD */
58 	if (!kfd2kgd) {
59 		struct kfd_dev *dev = NULL;
60 		unsigned int i = 0;
61 
62 		while ((kfd_topology_enum_kfd_devices(i, &dev)) == 0) {
63 			if (dev && dev->kfd2kgd) {
64 				kfd2kgd = dev->kfd2kgd;
65 				break;
66 			}
67 			i++;
68 		}
69 
70 		if (!kfd2kgd)
71 			return false;
72 	}
73 
74 	r = kfd2kgd->alloc_pasid(pasid_bits);
75 
76 	return r > 0 ? r : 0;
77 }
78 
79 void kfd_pasid_free(unsigned int pasid)
80 {
81 	if (kfd2kgd)
82 		kfd2kgd->free_pasid(pasid);
83 }
84