1 // SPDX-License-Identifier: GPL-2.0 OR MIT
2 /*
3  * Copyright 2014-2022 Advanced Micro Devices, Inc.
4  *
5  * Permission is hereby granted, free of charge, to any person obtaining a
6  * copy of this software and associated documentation files (the "Software"),
7  * to deal in the Software without restriction, including without limitation
8  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
9  * and/or sell copies of the Software, and to permit persons to whom the
10  * Software is furnished to do so, subject to the following conditions:
11  *
12  * The above copyright notice and this permission notice shall be included in
13  * all copies or substantial portions of the Software.
14  *
15  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
16  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
17  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
18  * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
19  * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
20  * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
21  * OTHER DEALINGS IN THE SOFTWARE.
22  */
23 
24 #include <linux/types.h>
25 #include "kfd_priv.h"
26 #include "amdgpu_ids.h"
27 
28 static unsigned int pasid_bits = 16;
29 static bool pasids_allocated; /* = false */
30 
31 bool kfd_set_pasid_limit(unsigned int new_limit)
32 {
33 	if (new_limit < 2)
34 		return false;
35 
36 	if (new_limit < (1U << pasid_bits)) {
37 		if (pasids_allocated)
38 			/* We've already allocated user PASIDs, too late to
39 			 * change the limit
40 			 */
41 			return false;
42 
43 		while (new_limit < (1U << pasid_bits))
44 			pasid_bits--;
45 	}
46 
47 	return true;
48 }
49 
50 unsigned int kfd_get_pasid_limit(void)
51 {
52 	return 1U << pasid_bits;
53 }
54 
55 u32 kfd_pasid_alloc(void)
56 {
57 	int r = amdgpu_pasid_alloc(pasid_bits);
58 
59 	if (r > 0) {
60 		pasids_allocated = true;
61 		return r;
62 	}
63 
64 	return 0;
65 }
66 
67 void kfd_pasid_free(u32 pasid)
68 {
69 	amdgpu_pasid_free(pasid);
70 }
71