/* * copy offload engine support * * Copyright © 2006, Intel Corporation. * * Dan Williams <dan.j.williams@intel.com> * * with architecture considerations by: * Neil Brown <neilb@suse.de> * Jeff Garzik <jeff@garzik.org> * * This program is free software; you can redistribute it and/or modify it * under the terms and conditions of the GNU General Public License, * version 2, as published by the Free Software Foundation. * * This program is distributed in the hope it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for * more details. * * You should have received a copy of the GNU General Public License along with * this program; if not, write to the Free Software Foundation, Inc., * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA. * */ #include <linux/kernel.h> #include <linux/highmem.h> #include <linux/mm.h> #include <linux/dma-mapping.h> #include <linux/async_tx.h> /** * async_memcpy - attempt to copy memory with a dma engine. * @dest: destination page * @src: src page * @offset: offset in pages to start transaction * @len: length in bytes * @flags: ASYNC_TX_ACK, ASYNC_TX_DEP_ACK, * @depend_tx: memcpy depends on the result of this transaction * @cb_fn: function to call when the memcpy completes * @cb_param: parameter to pass to the callback routine */ struct dma_async_tx_descriptor * async_memcpy(struct page *dest, struct page *src, unsigned int dest_offset, unsigned int src_offset, size_t len, enum async_tx_flags flags, struct dma_async_tx_descriptor *depend_tx, dma_async_tx_callback cb_fn, void *cb_param) { struct dma_chan *chan = async_tx_find_channel(depend_tx, DMA_MEMCPY, &dest, 1, &src, 1, len); struct dma_device *device = chan ? chan->device : NULL; struct dma_async_tx_descriptor *tx = NULL; if (device) { dma_addr_t dma_dest, dma_src; unsigned long dma_prep_flags = cb_fn ? DMA_PREP_INTERRUPT : 0; dma_dest = dma_map_page(device->dev, dest, dest_offset, len, DMA_FROM_DEVICE); dma_src = dma_map_page(device->dev, src, src_offset, len, DMA_TO_DEVICE); tx = device->device_prep_dma_memcpy(chan, dma_dest, dma_src, len, dma_prep_flags); } if (tx) { pr_debug("%s: (async) len: %zu\n", __func__, len); async_tx_submit(chan, tx, flags, depend_tx, cb_fn, cb_param); } else { void *dest_buf, *src_buf; pr_debug("%s: (sync) len: %zu\n", __func__, len); /* wait for any prerequisite operations */ async_tx_quiesce(&depend_tx); dest_buf = kmap_atomic(dest, KM_USER0) + dest_offset; src_buf = kmap_atomic(src, KM_USER1) + src_offset; memcpy(dest_buf, src_buf, len); kunmap_atomic(dest_buf, KM_USER0); kunmap_atomic(src_buf, KM_USER1); async_tx_sync_epilog(cb_fn, cb_param); } return tx; } EXPORT_SYMBOL_GPL(async_memcpy); static int __init async_memcpy_init(void) { return 0; } static void __exit async_memcpy_exit(void) { do { } while (0); } module_init(async_memcpy_init); module_exit(async_memcpy_exit); MODULE_AUTHOR("Intel Corporation"); MODULE_DESCRIPTION("asynchronous memcpy api"); MODULE_LICENSE("GPL");