0036731c88
The tx_set_src and tx_set_dest methods were originally implemented to allow an array of addresses to be passed down from async_xor to the dmaengine driver while minimizing stack overhead. Removing these methods allows drivers to have all transaction parameters available at 'prep' time, saves two function pointers in struct dma_async_tx_descriptor, and reduces the number of indirect branches.. A consequence of moving this data to the 'prep' routine is that multi-source routines like async_xor need temporary storage to convert an array of linear addresses into an array of dma addresses. In order to keep the same stack footprint of the previous implementation the input array is reused as storage for the dma addresses. This requires that sizeof(dma_addr_t) be less than or equal to sizeof(void *). As a consequence CONFIG_DMADEVICES now depends on !CONFIG_HIGHMEM64G. It also requires that drivers be able to make descriptor resources available when the 'prep' routine is polled. Signed-off-by: Dan Williams <dan.j.williams@intel.com> Acked-by: Shannon Nelson <shannon.nelson@intel.com>
108 lines
3.1 KiB
C
108 lines
3.1 KiB
C
/*
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* memory fill 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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* This program is free software; you can redistribute it and/or modify it
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* under the terms and conditions of the GNU General Public License,
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* version 2, as published by the Free Software Foundation.
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*
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* This program is distributed in the hope it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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* more details.
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*
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* You should have received a copy of the GNU General Public License along with
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* this program; if not, write to the Free Software Foundation, Inc.,
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* 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
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*
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*/
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#include <linux/kernel.h>
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#include <linux/interrupt.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_memset - attempt to fill memory with a dma engine.
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* @dest: destination page
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* @val: fill value
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* @offset: offset in pages to start transaction
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* @len: length in bytes
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* @flags: ASYNC_TX_ACK, ASYNC_TX_DEP_ACK
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* @depend_tx: memset depends on the result of this transaction
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* @cb_fn: function to call when the memcpy completes
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* @cb_param: parameter to pass to the callback routine
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*/
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struct dma_async_tx_descriptor *
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async_memset(struct page *dest, int val, unsigned int offset,
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size_t len, enum async_tx_flags flags,
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struct dma_async_tx_descriptor *depend_tx,
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dma_async_tx_callback cb_fn, void *cb_param)
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{
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struct dma_chan *chan = async_tx_find_channel(depend_tx, DMA_MEMSET);
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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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if (device) {
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dma_addr_t dma_dest;
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dma_dest = dma_map_page(device->dev, dest, offset, len,
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DMA_FROM_DEVICE);
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tx = device->device_prep_dma_memset(chan, dma_dest, val, len,
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cb_fn != NULL);
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}
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if (tx) {
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pr_debug("%s: (async) len: %zu\n", __FUNCTION__, len);
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async_tx_submit(chan, tx, flags, depend_tx, cb_fn, cb_param);
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} else { /* run the memset synchronously */
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void *dest_buf;
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pr_debug("%s: (sync) len: %zu\n", __FUNCTION__, len);
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dest_buf = (void *) (((char *) page_address(dest)) + offset);
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/* wait for any prerequisite operations */
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if (depend_tx) {
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/* if ack is already set then we cannot be sure
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* we are referring to the correct operation
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*/
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BUG_ON(depend_tx->ack);
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if (dma_wait_for_async_tx(depend_tx) == DMA_ERROR)
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panic("%s: DMA_ERROR waiting for depend_tx\n",
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__FUNCTION__);
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}
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memset(dest_buf, val, len);
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async_tx_sync_epilog(flags, depend_tx, cb_fn, cb_param);
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}
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return tx;
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}
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EXPORT_SYMBOL_GPL(async_memset);
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static int __init async_memset_init(void)
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{
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return 0;
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}
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static void __exit async_memset_exit(void)
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{
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do { } while (0);
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}
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module_init(async_memset_init);
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module_exit(async_memset_exit);
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MODULE_AUTHOR("Intel Corporation");
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MODULE_DESCRIPTION("asynchronous memset api");
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MODULE_LICENSE("GPL");
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