/* * memory fill 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/interrupt.h> #include <linux/mm.h> #include <linux/dma-mapping.h> #include <linux/async_tx.h> /** * async_memset - attempt to fill memory with a dma engine. * @dest: destination page * @val: fill value * @offset: offset in pages to start transaction * @len: length in bytes * @flags: ASYNC_TX_ASSUME_COHERENT, ASYNC_TX_ACK, ASYNC_TX_DEP_ACK * @depend_tx: memset 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_memset(struct page *dest, int val, unsigned int 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_MEMSET); struct dma_device *device = chan ? chan->device : NULL; int int_en = cb_fn ? 1 : 0; struct dma_async_tx_descriptor *tx = device ? device->device_prep_dma_memset(chan, val, len, int_en) : NULL; if (tx) { /* run the memset asynchronously */ dma_addr_t dma_addr; enum dma_data_direction dir; pr_debug("%s: (async) len: %zu\n", __FUNCTION__, len); dir = (flags & ASYNC_TX_ASSUME_COHERENT) ? DMA_NONE : DMA_FROM_DEVICE; dma_addr = dma_map_page(device->dev, dest, offset, len, dir); tx->tx_set_dest(dma_addr, tx, 0); async_tx_submit(chan, tx, flags, depend_tx, cb_fn, cb_param); } else { /* run the memset synchronously */ void *dest_buf; pr_debug("%s: (sync) len: %zu\n", __FUNCTION__, len); dest_buf = (void *) (((char *) page_address(dest)) + offset); /* wait for any prerequisite operations */ if (depend_tx) { /* if ack is already set then we cannot be sure * we are referring to the correct operation */ BUG_ON(depend_tx->ack); if (dma_wait_for_async_tx(depend_tx) == DMA_ERROR) panic("%s: DMA_ERROR waiting for depend_tx\n", __FUNCTION__); } memset(dest_buf, val, len); async_tx_sync_epilog(flags, depend_tx, cb_fn, cb_param); } return tx; } EXPORT_SYMBOL_GPL(async_memset); static int __init async_memset_init(void) { return 0; } static void __exit async_memset_exit(void) { do { } while (0); } module_init(async_memset_init); module_exit(async_memset_exit); MODULE_AUTHOR("Intel Corporation"); MODULE_DESCRIPTION("asynchronous memset api"); MODULE_LICENSE("GPL");