// SPDX-License-Identifier: GPL-2.0-only
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/*
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* copy offload engine support
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*
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* Copyright © 2006, Intel Corporation.
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*
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* Dan Williams <dan.j.williams@intel.com>
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*
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* with architecture considerations by:
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* Neil Brown <neilb@suse.de>
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* Jeff Garzik <jeff@garzik.org>
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*/
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#include <linux/kernel.h>
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#include <linux/highmem.h>
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#include <linux/module.h>
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#include <linux/mm.h>
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#include <linux/dma-mapping.h>
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#include <linux/async_tx.h>
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/**
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* async_memcpy - attempt to copy memory with a dma engine.
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* @dest: destination page
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* @src: src page
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* @dest_offset: offset into 'dest' to start transaction
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* @src_offset: offset into 'src' to start transaction
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* @len: length in bytes
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* @submit: submission / completion modifiers
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*
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* honored flags: ASYNC_TX_ACK
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*/
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struct dma_async_tx_descriptor *
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async_memcpy(struct page *dest, struct page *src, unsigned int dest_offset,
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unsigned int src_offset, size_t len,
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struct async_submit_ctl *submit)
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{
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struct dma_chan *chan = async_tx_find_channel(submit, DMA_MEMCPY,
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&dest, 1, &src, 1, len);
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struct dma_device *device = chan ? chan->device : NULL;
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struct dma_async_tx_descriptor *tx = NULL;
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struct dmaengine_unmap_data *unmap = NULL;
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if (device)
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unmap = dmaengine_get_unmap_data(device->dev, 2, GFP_NOWAIT);
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if (unmap && is_dma_copy_aligned(device, src_offset, dest_offset, len)) {
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unsigned long dma_prep_flags = 0;
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if (submit->cb_fn)
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dma_prep_flags |= DMA_PREP_INTERRUPT;
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if (submit->flags & ASYNC_TX_FENCE)
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dma_prep_flags |= DMA_PREP_FENCE;
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unmap->to_cnt = 1;
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unmap->addr[0] = dma_map_page(device->dev, src, src_offset, len,
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DMA_TO_DEVICE);
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unmap->from_cnt = 1;
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unmap->addr[1] = dma_map_page(device->dev, dest, dest_offset, len,
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DMA_FROM_DEVICE);
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unmap->len = len;
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tx = device->device_prep_dma_memcpy(chan, unmap->addr[1],
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unmap->addr[0], len,
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dma_prep_flags);
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}
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if (tx) {
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pr_debug("%s: (async) len: %zu\n", __func__, len);
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dma_set_unmap(tx, unmap);
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async_tx_submit(chan, tx, submit);
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} else {
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void *dest_buf, *src_buf;
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pr_debug("%s: (sync) len: %zu\n", __func__, len);
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/* wait for any prerequisite operations */
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async_tx_quiesce(&submit->depend_tx);
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dest_buf = kmap_atomic(dest) + dest_offset;
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src_buf = kmap_atomic(src) + src_offset;
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memcpy(dest_buf, src_buf, len);
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kunmap_atomic(src_buf);
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kunmap_atomic(dest_buf);
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async_tx_sync_epilog(submit);
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}
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dmaengine_unmap_put(unmap);
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return tx;
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}
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EXPORT_SYMBOL_GPL(async_memcpy);
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MODULE_AUTHOR("Intel Corporation");
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MODULE_DESCRIPTION("asynchronous memcpy api");
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MODULE_LICENSE("GPL");
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