LXR linux/crypto/async_tx/async

   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 * copy offload engine support
   4 *
   5 * Copyright © 2006, Intel Corporation.
   6 *
   7 *      Dan Williams <dan.j.williams@intel.com>
   8 *
   9 *      with architecture considerations by:
  10 *      Neil Brown <neilb@suse.de>
  11 *      Jeff Garzik <jeff@garzik.org>
  12 */
  13#include <linux/kernel.h>
  14#include <linux/highmem.h>
  15#include <linux/module.h>
  16#include <linux/mm.h>
  17#include <linux/dma-mapping.h>
  18#include <linux/async_tx.h>
  19
  20/**
  21 * async_memcpy - attempt to copy memory with a dma engine.
  22 * @dest: destination page
  23 * @src: src page
  24 * @dest_offset: offset into 'dest' to start transaction
  25 * @src_offset: offset into 'src' to start transaction
  26 * @len: length in bytes
  27 * @submit: submission / completion modifiers
  28 *
  29 * honored flags: ASYNC_TX_ACK
  30 */
  31struct dma_async_tx_descriptor *
  32async_memcpy(struct page *dest, struct page *src, unsigned int dest_offset,
  33             unsigned int src_offset, size_t len,
  34             struct async_submit_ctl *submit)
  35{
  36        struct dma_chan *chan = async_tx_find_channel(submit, DMA_MEMCPY,
  37                                                      &dest, 1, &src, 1, len);
  38        struct dma_device *device = chan ? chan->device : NULL;
  39        struct dma_async_tx_descriptor *tx = NULL;
  40        struct dmaengine_unmap_data *unmap = NULL;
  41
  42        if (device)
  43                unmap = dmaengine_get_unmap_data(device->dev, 2, GFP_NOWAIT);
  44
  45        if (unmap && is_dma_copy_aligned(device, src_offset, dest_offset, len)) {
  46                unsigned long dma_prep_flags = 0;
  47
  48                if (submit->cb_fn)
  49                        dma_prep_flags |= DMA_PREP_INTERRUPT;
  50                if (submit->flags & ASYNC_TX_FENCE)
  51                        dma_prep_flags |= DMA_PREP_FENCE;
  52
  53                unmap->to_cnt = 1;
  54                unmap->addr[0] = dma_map_page(device->dev, src, src_offset, len,
  55                                              DMA_TO_DEVICE);
  56                unmap->from_cnt = 1;
  57                unmap->addr[1] = dma_map_page(device->dev, dest, dest_offset, len,
  58                                              DMA_FROM_DEVICE);
  59                unmap->len = len;
  60
  61                tx = device->device_prep_dma_memcpy(chan, unmap->addr[1],
  62                                                    unmap->addr[0], len,
  63                                                    dma_prep_flags);
  64        }
  65
  66        if (tx) {
  67                pr_debug("%s: (async) len: %zu\n", __func__, len);
  68
  69                dma_set_unmap(tx, unmap);
  70                async_tx_submit(chan, tx, submit);
  71        } else {
  72                void *dest_buf, *src_buf;
  73                pr_debug("%s: (sync) len: %zu\n", __func__, len);
  74
  75                /* wait for any prerequisite operations */
  76                async_tx_quiesce(&submit->depend_tx);
  77
  78                dest_buf = kmap_atomic(dest) + dest_offset;
  79                src_buf = kmap_atomic(src) + src_offset;
  80
  81                memcpy(dest_buf, src_buf, len);
  82
  83                kunmap_atomic(src_buf);
  84                kunmap_atomic(dest_buf);
  85
  86                async_tx_sync_epilog(submit);
  87        }
  88
  89        dmaengine_unmap_put(unmap);
  90
  91        return tx;
  92}
  93EXPORT_SYMBOL_GPL(async_memcpy);
  94
  95MODULE_AUTHOR("Intel Corporation");
  96MODULE_DESCRIPTION("asynchronous memcpy api");
  97MODULE_LICENSE("GPL");
  98