| John Scheible | de16475 | 2021-10-26 13:45:19 -0700 | [diff] [blame] | 1 | /* SPDX-License-Identifier: GPL-2.0 */ |
| 2 | /* |
| 3 | * GXP ranged resource allocator. |
| 4 | * |
| 5 | * Copyright (C) 2021 Google LLC |
| 6 | */ |
| 7 | #ifndef __GXP_RANGE_ALLOC_H__ |
| 8 | #define __GXP_RANGE_ALLOC_H__ |
| 9 | |
| 10 | #include <linux/mutex.h> |
| 11 | #include <linux/slab.h> |
| 12 | |
| 13 | struct range_alloc { |
| 14 | int total_count; |
| 15 | int free_count; |
| 16 | int start_index; |
| 17 | struct mutex lock; |
| 18 | int elements[]; |
| 19 | }; |
| 20 | |
| 21 | /** |
| 22 | * range_alloc_create() - Creates a range allocator starting at the specified |
| 23 | * start (inclusive) and ends at the specified end |
| 24 | * (exclusive). |
| 25 | * @start: The start of the range (inclusive). |
| 26 | * @end: The end of the range (exclusive) |
| 27 | * |
| 28 | * Return: |
| 29 | * ptr - A pointer of the newly created allocator handle on success, an |
| 30 | * error pointer (PTR_ERR) otherwise. |
| 31 | * -EINVAL - Invalid start/end combination |
| 32 | * -ENOMEM - Insufficient memory to create the allocator |
| 33 | */ |
| 34 | struct range_alloc *range_alloc_create(int start, int end); |
| 35 | |
| 36 | /** |
| 37 | * range_alloc_get() - Gets the specified element from the range. |
| 38 | * @r: The range allocator |
| 39 | * @element: The element to acquire from the range |
| 40 | * |
| 41 | * The @element argument should be within the allocator's range and has not been |
| 42 | * allocated before. |
| 43 | * |
| 44 | * Return: |
| 45 | * 0 - Successfully reserved @element |
| 46 | * -EINVAL - Invalid element index (negative or outside allocator range) |
| 47 | * -EBUSY - Element is already allocated |
| 48 | */ |
| 49 | int range_alloc_get(struct range_alloc *r, int element); |
| 50 | |
| 51 | /** |
| 52 | * range_alloc_get_any() - Gets any free element in the range. |
| 53 | * @r: The range allocator |
| 54 | * @element: A pointer to use to store the allocated element |
| 55 | * |
| 56 | * Return: |
| 57 | * 0 - Successful reservation |
| 58 | * -ENOMEM - No elements left in the range to allocate |
| 59 | */ |
| 60 | int range_alloc_get_any(struct range_alloc *r, int *element); |
| 61 | |
| 62 | /** |
| 63 | * range_alloc_put() - Puts an element back into the range. |
| 64 | * @r: The range allocator |
| 65 | * @element: The element to put back into the range |
| 66 | * |
| 67 | * Return: |
| 68 | * 0 - Successful placement back into the range |
| 69 | * -EINVAL - Invalid element index (negative or outside allocator range) |
| 70 | * -EBUSY - The element is still present in the range |
| 71 | */ |
| 72 | int range_alloc_put(struct range_alloc *r, int element); |
| 73 | |
| 74 | /** |
| 75 | * range_alloc_num_free() - Returns the number of free elements in the range. |
| 76 | * @r: The range allocator |
| 77 | * |
| 78 | * Return: the number of free elements in the range |
| 79 | */ |
| 80 | int range_alloc_num_free(struct range_alloc *r); |
| 81 | |
| 82 | /** |
| 83 | * range_alloc_destroy() - Destroys the range allocator |
| 84 | * @r: The range allocator to destroy |
| 85 | * |
| 86 | * The destruction does not validate that the range is empty. |
| 87 | * |
| 88 | * Return: |
| 89 | * 0 - Successfully destroyed range allocator |
| 90 | * -EFAULT - Invalid allocator address |
| 91 | */ |
| 92 | int range_alloc_destroy(struct range_alloc *r); |
| 93 | |
| 94 | #endif /* __GXP_RANGE_ALLOC_H__ */ |