crypto/async_tx/async_memcpy.c

   1 /*
   2  * copy offload engine support
   3  *
   4  * Copyright © 2006, Intel Corporation.
   5  *
   6  *      Dan Williams <dan.j.williams@intel.com>
   7  *
   8  *      with architecture considerations by:
   9  *      Neil Brown <neilb@suse.de>
  10  *      Jeff Garzik <jeff@garzik.org>
  11  *
  12  * This program is free software; you can redistribute it and/or modify it
  13  * under the terms and conditions of the GNU General Public License,
  14  * version 2, as published by the Free Software Foundation.
  15  *
  16  * This program is distributed in the hope it will be useful, but WITHOUT
  17  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  18  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  19  * more details.
  20  *
  21  * You should have received a copy of the GNU General Public License along with
  22  * this program; if not, write to the Free Software Foundation, Inc.,
  23  * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
  24  *
  25  */
  26 #include <linux/kernel.h>
  27 #include <linux/highmem.h>
  28 #include <linux/mm.h>
  29 #include <linux/dma-mapping.h>
  30 #include <linux/async_tx.h>
  31
  32 /**
  33  * async_memcpy - attempt to copy memory with a dma engine.
  34  * @dest: destination page
  35  * @src: src page
  36  * @offset: offset in pages to start transaction
  37  * @len: length in bytes
  38  * @flags: ASYNC_TX_ACK, ASYNC_TX_DEP_ACK,
  39  * @depend_tx: memcpy depends on the result of this transaction
  40  * @cb_fn: function to call when the memcpy completes
  41  * @cb_param: parameter to pass to the callback routine
  42  */
  43 struct dma_async_tx_descriptor *
  44 async_memcpy(struct page *dest, struct page *src, unsigned int dest_offset,
  45         unsigned int src_offset, size_t len, enum async_tx_flags flags,
  46         struct dma_async_tx_descriptor *depend_tx,
  47         dma_async_tx_callback cb_fn, void *cb_param)
  48 {
  49         struct dma_chan *chan = async_tx_find_channel(depend_tx, DMA_MEMCPY,
  50                                                       &dest, 1, &src, 1, len);
  51         struct dma_device *device = chan ? chan->device : NULL;
  52         struct dma_async_tx_descriptor *tx = NULL;
  53
  54         if (device) {
  55                 dma_addr_t dma_dest, dma_src;
  56                 unsigned long dma_prep_flags = cb_fn ? DMA_PREP_INTERRUPT : 0;
  57
  58                 dma_dest = dma_map_page(device->dev, dest, dest_offset, len,
  59                                         DMA_FROM_DEVICE);
  60
  61                 dma_src = dma_map_page(device->dev, src, src_offset, len,
  62                                        DMA_TO_DEVICE);
  63
  64                 tx = device->device_prep_dma_memcpy(chan, dma_dest, dma_src,
  65                                                     len, dma_prep_flags);
  66         }
  67
  68         if (tx) {
  69                 pr_debug("%s: (async) len: %zu\n", __func__, len);
  70                 async_tx_submit(chan, tx, flags, depend_tx, cb_fn, cb_param);
  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                 if (depend_tx) {
  77                         /* if ack is already set then we cannot be sure
  78                          * we are referring to the correct operation
  79                          */
  80                         BUG_ON(async_tx_test_ack(depend_tx));
  81                         if (dma_wait_for_async_tx(depend_tx) == DMA_ERROR)
  82                                 panic("%s: DMA_ERROR waiting for depend_tx\n",
  83                                         __func__);
  84                 }
  85
  86                 dest_buf = kmap_atomic(dest, KM_USER0) + dest_offset;
  87                 src_buf = kmap_atomic(src, KM_USER1) + src_offset;
  88
  89                 memcpy(dest_buf, src_buf, len);
  90
  91                 kunmap_atomic(dest_buf, KM_USER0);
  92                 kunmap_atomic(src_buf, KM_USER1);
  93
  94                 async_tx_sync_epilog(flags, depend_tx, cb_fn, cb_param);
  95         }
  96
  97         return tx;
  98 }
  99 EXPORT_SYMBOL_GPL(async_memcpy);
 100
 101 static int __init async_memcpy_init(void)
 102 {
 103         return 0;
 104 }
 105
 106 static void __exit async_memcpy_exit(void)
 107 {
 108         do { } while (0);
 109 }
 110
 111 module_init(async_memcpy_init);
 112 module_exit(async_memcpy_exit);
 113
 114 MODULE_AUTHOR("Intel Corporation");
 115 MODULE_DESCRIPTION("asynchronous memcpy api");
 116 MODULE_LICENSE("GPL");