1 /* 2 * dma-fence-array: aggregate fences to be waited together 3 * 4 * Copyright (C) 2016 Collabora Ltd 5 * Copyright (C) 2016 Advanced Micro Devices, Inc. 6 * Authors: 7 * Gustavo Padovan <gustavo@padovan.org> 8 * Christian König <christian.koenig@amd.com> 9 * 10 * This program is free software; you can redistribute it and/or modify it 11 * under the terms of the GNU General Public License version 2 as published by 12 * the Free Software Foundation. 13 * 14 * This program is distributed in the hope that it will be useful, but WITHOUT 15 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 16 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for 17 * more details. 18 */ 19 20 #include <linux/export.h> 21 #include <linux/slab.h> 22 #include <linux/dma-fence-array.h> 23 24 static const char *dma_fence_array_get_driver_name(struct dma_fence *fence) 25 { 26 return "dma_fence_array"; 27 } 28 29 static const char *dma_fence_array_get_timeline_name(struct dma_fence *fence) 30 { 31 return "unbound"; 32 } 33 34 static void dma_fence_array_cb_func(struct dma_fence *f, 35 struct dma_fence_cb *cb) 36 { 37 struct dma_fence_array_cb *array_cb = 38 container_of(cb, struct dma_fence_array_cb, cb); 39 struct dma_fence_array *array = array_cb->array; 40 41 if (atomic_dec_and_test(&array->num_pending)) 42 dma_fence_signal(&array->base); 43 dma_fence_put(&array->base); 44 } 45 46 static bool dma_fence_array_enable_signaling(struct dma_fence *fence) 47 { 48 struct dma_fence_array *array = to_dma_fence_array(fence); 49 struct dma_fence_array_cb *cb = (void *)(&array[1]); 50 unsigned i; 51 52 for (i = 0; i < array->num_fences; ++i) { 53 cb[i].array = array; 54 /* 55 * As we may report that the fence is signaled before all 56 * callbacks are complete, we need to take an additional 57 * reference count on the array so that we do not free it too 58 * early. The core fence handling will only hold the reference 59 * until we signal the array as complete (but that is now 60 * insufficient). 61 */ 62 dma_fence_get(&array->base); 63 if (dma_fence_add_callback(array->fences[i], &cb[i].cb, 64 dma_fence_array_cb_func)) { 65 dma_fence_put(&array->base); 66 if (atomic_dec_and_test(&array->num_pending)) 67 return false; 68 } 69 } 70 71 return true; 72 } 73 74 static bool dma_fence_array_signaled(struct dma_fence *fence) 75 { 76 struct dma_fence_array *array = to_dma_fence_array(fence); 77 78 return atomic_read(&array->num_pending) <= 0; 79 } 80 81 static void dma_fence_array_release(struct dma_fence *fence) 82 { 83 struct dma_fence_array *array = to_dma_fence_array(fence); 84 unsigned i; 85 86 for (i = 0; i < array->num_fences; ++i) 87 dma_fence_put(array->fences[i]); 88 89 kfree(array->fences); 90 dma_fence_free(fence); 91 } 92 93 const struct dma_fence_ops dma_fence_array_ops = { 94 .get_driver_name = dma_fence_array_get_driver_name, 95 .get_timeline_name = dma_fence_array_get_timeline_name, 96 .enable_signaling = dma_fence_array_enable_signaling, 97 .signaled = dma_fence_array_signaled, 98 .wait = dma_fence_default_wait, 99 .release = dma_fence_array_release, 100 }; 101 EXPORT_SYMBOL(dma_fence_array_ops); 102 103 /** 104 * dma_fence_array_create - Create a custom fence array 105 * @num_fences: [in] number of fences to add in the array 106 * @fences: [in] array containing the fences 107 * @context: [in] fence context to use 108 * @seqno: [in] sequence number to use 109 * @signal_on_any: [in] signal on any fence in the array 110 * 111 * Allocate a dma_fence_array object and initialize the base fence with 112 * dma_fence_init(). 113 * In case of error it returns NULL. 114 * 115 * The caller should allocate the fences array with num_fences size 116 * and fill it with the fences it wants to add to the object. Ownership of this 117 * array is taken and dma_fence_put() is used on each fence on release. 118 * 119 * If @signal_on_any is true the fence array signals if any fence in the array 120 * signals, otherwise it signals when all fences in the array signal. 121 */ 122 struct dma_fence_array *dma_fence_array_create(int num_fences, 123 struct dma_fence **fences, 124 u64 context, unsigned seqno, 125 bool signal_on_any) 126 { 127 struct dma_fence_array *array; 128 size_t size = sizeof(*array); 129 130 /* Allocate the callback structures behind the array. */ 131 size += num_fences * sizeof(struct dma_fence_array_cb); 132 array = kzalloc(size, GFP_KERNEL); 133 if (!array) 134 return NULL; 135 136 spin_lock_init(&array->lock); 137 dma_fence_init(&array->base, &dma_fence_array_ops, &array->lock, 138 context, seqno); 139 140 array->num_fences = num_fences; 141 atomic_set(&array->num_pending, signal_on_any ? 1 : num_fences); 142 array->fences = fences; 143 144 return array; 145 } 146 EXPORT_SYMBOL(dma_fence_array_create); 147