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/*
 *
 * Copyright (c) 2013 Cisco and/or its affiliates.
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at:
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
/**
 @dir
 @brief LISP-GPE code.

 An implementation of LISP-GPE as per:
 rfc-6830
 draft-lewis-lisp-gpe-02

 See file: rfc.txt

*/
-------- This plugin utilize platform DMA accelerators like CBDMA/DSA for streaming data movement. Modern DMA accelerators has high memory bandwidth and benefit cross-numa traffic. Accelerator like DSA has the capability to do IO page fault recovery, it will save IOMMU setup for the memory which not pinned. Terminology & Usage ------------------- A ``backend`` is the abstract of resource which inherited from DMA device, it support necessary operations for DMA offloading like configuration, DMA request and result query. A ``config`` is the abstract of application DMA capability. Application can request a config instance through DMA node. DMA node will check the requirements of application and bind suitable backend with it. Enable DSA work queue: ---------------------- .. code-block:: console # configure 1 groups, each with one engine accel-config config-engine dsa0/engine0.0 --group-id=0 # configure 1 queues, putting each in a different group, so each # is backed by a single engine accel-config config-wq dsa0/wq0.0 --group-id=0 --type=user \ --priority=10 --max-batch-size=1024 --mode=dedicated -b 1 -a 0 --name=vpp1 DMA transfer: ------------- In this sample, application will request DMA capability which can hold a batch contained maximum 256 transfers and each transfer hold maximum 4K bytes from DMA node. If config_index value is not negative, mean resource has been allocated and DMA engine is ready for serve. .. code-block:: console void dma_completion_cb (vlib_main_t *vm, vlib_dma_batch_t *b); vlib_dma_config_args_t args; args->max_transfers = 256; args->max_transfer_size = 4096; args->cpu_fallback = 1; args->barrier_before_last = 1; args->cb = dma_completion_cb; u32 config_index = vlib_dma_config (vm, &args); if (config_index < 0) return; u8 *dst[n_transfers]; u8 *src[n_transfers]; u32 i = 0, size = 4096; vlib_dma_batch_t *b; b = vlib_dma_batch_new (vm, config_index); while (wrk_t->config_index >= 0 && n_transfers) { vlib_dma_batch_add (vm, b, dst[i], src[i], size); n_transfers --; i ++; } vlib_dma_batch_submit (vm, config_index);