1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * dma-fence-array: aggregate fences to be waited together 4 * 5 * Copyright (C) 2016 Collabora Ltd 6 * Copyright (C) 2016 Advanced Micro Devices, Inc. 7 * Authors: 8 * Gustavo Padovan <gustavo@padovan.org> 9 * Christian König <christian.koenig@amd.com> 10 */ 11 12 #include <linux/export.h> 13 #include <linux/slab.h> 14 #include <linux/dma-fence-array.h> 15 16 #define PENDING_ERROR 1 17 18 static const char *dma_fence_array_get_driver_name(struct dma_fence *fence) 19 { 20 return "dma_fence_array"; 21 } 22 23 static const char *dma_fence_array_get_timeline_name(struct dma_fence *fence) 24 { 25 return "unbound"; 26 } 27 28 static void dma_fence_array_set_pending_error(struct dma_fence_array *array, 29 int error) 30 { 31 /* 32 * Propagate the first error reported by any of our fences, but only 33 * before we ourselves are signaled. 34 */ 35 if (error) 36 cmpxchg(&array->base.error, PENDING_ERROR, error); 37 } 38 39 static void dma_fence_array_clear_pending_error(struct dma_fence_array *array) 40 { 41 /* Clear the error flag if not actually set. */ 42 cmpxchg(&array->base.error, PENDING_ERROR, 0); 43 } 44 45 static void irq_dma_fence_array_work(struct irq_work *wrk) 46 { 47 struct dma_fence_array *array = container_of(wrk, typeof(*array), work); 48 49 dma_fence_array_clear_pending_error(array); 50 51 dma_fence_signal(&array->base); 52 dma_fence_put(&array->base); 53 } 54 55 static void dma_fence_array_cb_func(struct dma_fence *f, 56 struct dma_fence_cb *cb) 57 { 58 struct dma_fence_array_cb *array_cb = 59 container_of(cb, struct dma_fence_array_cb, cb); 60 struct dma_fence_array *array = array_cb->array; 61 62 dma_fence_array_set_pending_error(array, f->error); 63 64 if (atomic_dec_and_test(&array->num_pending)) 65 irq_work_queue(&array->work); 66 else 67 dma_fence_put(&array->base); 68 } 69 70 static bool dma_fence_array_enable_signaling(struct dma_fence *fence) 71 { 72 struct dma_fence_array *array = to_dma_fence_array(fence); 73 struct dma_fence_array_cb *cb = (void *)(&array[1]); 74 unsigned i; 75 76 for (i = 0; i < array->num_fences; ++i) { 77 cb[i].array = array; 78 /* 79 * As we may report that the fence is signaled before all 80 * callbacks are complete, we need to take an additional 81 * reference count on the array so that we do not free it too 82 * early. The core fence handling will only hold the reference 83 * until we signal the array as complete (but that is now 84 * insufficient). 85 */ 86 dma_fence_get(&array->base); 87 if (dma_fence_add_callback(array->fences[i], &cb[i].cb, 88 dma_fence_array_cb_func)) { 89 int error = array->fences[i]->error; 90 91 dma_fence_array_set_pending_error(array, error); 92 dma_fence_put(&array->base); 93 if (atomic_dec_and_test(&array->num_pending)) { 94 dma_fence_array_clear_pending_error(array); 95 return false; 96 } 97 } 98 } 99 100 return true; 101 } 102 103 static bool dma_fence_array_signaled(struct dma_fence *fence) 104 { 105 struct dma_fence_array *array = to_dma_fence_array(fence); 106 107 if (atomic_read(&array->num_pending) > 0) 108 return false; 109 110 dma_fence_array_clear_pending_error(array); 111 return true; 112 } 113 114 static void dma_fence_array_release(struct dma_fence *fence) 115 { 116 struct dma_fence_array *array = to_dma_fence_array(fence); 117 unsigned i; 118 119 for (i = 0; i < array->num_fences; ++i) 120 dma_fence_put(array->fences[i]); 121 122 kfree(array->fences); 123 dma_fence_free(fence); 124 } 125 126 static void dma_fence_array_set_deadline(struct dma_fence *fence, 127 ktime_t deadline) 128 { 129 struct dma_fence_array *array = to_dma_fence_array(fence); 130 unsigned i; 131 132 for (i = 0; i < array->num_fences; ++i) 133 dma_fence_set_deadline(array->fences[i], deadline); 134 } 135 136 const struct dma_fence_ops dma_fence_array_ops = { 137 .get_driver_name = dma_fence_array_get_driver_name, 138 .get_timeline_name = dma_fence_array_get_timeline_name, 139 .enable_signaling = dma_fence_array_enable_signaling, 140 .signaled = dma_fence_array_signaled, 141 .release = dma_fence_array_release, 142 .set_deadline = dma_fence_array_set_deadline, 143 }; 144 EXPORT_SYMBOL(dma_fence_array_ops); 145 146 /** 147 * dma_fence_array_create - Create a custom fence array 148 * @num_fences: [in] number of fences to add in the array 149 * @fences: [in] array containing the fences 150 * @context: [in] fence context to use 151 * @seqno: [in] sequence number to use 152 * @signal_on_any: [in] signal on any fence in the array 153 * 154 * Allocate a dma_fence_array object and initialize the base fence with 155 * dma_fence_init(). 156 * In case of error it returns NULL. 157 * 158 * The caller should allocate the fences array with num_fences size 159 * and fill it with the fences it wants to add to the object. Ownership of this 160 * array is taken and dma_fence_put() is used on each fence on release. 161 * 162 * If @signal_on_any is true the fence array signals if any fence in the array 163 * signals, otherwise it signals when all fences in the array signal. 164 */ 165 struct dma_fence_array *dma_fence_array_create(int num_fences, 166 struct dma_fence **fences, 167 u64 context, unsigned seqno, 168 bool signal_on_any) 169 { 170 struct dma_fence_array *array; 171 size_t size = sizeof(*array); 172 173 WARN_ON(!num_fences || !fences); 174 175 /* Allocate the callback structures behind the array. */ 176 size += num_fences * sizeof(struct dma_fence_array_cb); 177 array = kzalloc(size, GFP_KERNEL); 178 if (!array) 179 return NULL; 180 181 spin_lock_init(&array->lock); 182 dma_fence_init(&array->base, &dma_fence_array_ops, &array->lock, 183 context, seqno); 184 init_irq_work(&array->work, irq_dma_fence_array_work); 185 186 array->num_fences = num_fences; 187 atomic_set(&array->num_pending, signal_on_any ? 1 : num_fences); 188 array->fences = fences; 189 190 array->base.error = PENDING_ERROR; 191 192 /* 193 * dma_fence_array objects should never contain any other fence 194 * containers or otherwise we run into recursion and potential kernel 195 * stack overflow on operations on the dma_fence_array. 196 * 197 * The correct way of handling this is to flatten out the array by the 198 * caller instead. 199 * 200 * Enforce this here by checking that we don't create a dma_fence_array 201 * with any container inside. 202 */ 203 while (num_fences--) 204 WARN_ON(dma_fence_is_container(fences[num_fences])); 205 206 return array; 207 } 208 EXPORT_SYMBOL(dma_fence_array_create); 209 210 /** 211 * dma_fence_match_context - Check if all fences are from the given context 212 * @fence: [in] fence or fence array 213 * @context: [in] fence context to check all fences against 214 * 215 * Checks the provided fence or, for a fence array, all fences in the array 216 * against the given context. Returns false if any fence is from a different 217 * context. 218 */ 219 bool dma_fence_match_context(struct dma_fence *fence, u64 context) 220 { 221 struct dma_fence_array *array = to_dma_fence_array(fence); 222 unsigned i; 223 224 if (!dma_fence_is_array(fence)) 225 return fence->context == context; 226 227 for (i = 0; i < array->num_fences; i++) { 228 if (array->fences[i]->context != context) 229 return false; 230 } 231 232 return true; 233 } 234 EXPORT_SYMBOL(dma_fence_match_context); 235 236 struct dma_fence *dma_fence_array_first(struct dma_fence *head) 237 { 238 struct dma_fence_array *array; 239 240 if (!head) 241 return NULL; 242 243 array = to_dma_fence_array(head); 244 if (!array) 245 return head; 246 247 if (!array->num_fences) 248 return NULL; 249 250 return array->fences[0]; 251 } 252 EXPORT_SYMBOL(dma_fence_array_first); 253 254 struct dma_fence *dma_fence_array_next(struct dma_fence *head, 255 unsigned int index) 256 { 257 struct dma_fence_array *array = to_dma_fence_array(head); 258 259 if (!array || index >= array->num_fences) 260 return NULL; 261 262 return array->fences[index]; 263 } 264 EXPORT_SYMBOL(dma_fence_array_next); 265