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_ASSUME_COHERENT, ASYNC_TX_ACK, ASYNC_TX_DEP_ACK,
  39  *      ASYNC_TX_KMAP_SRC, ASYNC_TX_KMAP_DST
  40  * @depend_tx: memcpy depends on the result of this transaction
  41  * @cb_fn: function to call when the memcpy completes
  42  * @cb_param: parameter to pass to the callback routine
  43  */
  44 struct dma_async_tx_descriptor *
  45 async_memcpy(struct page *dest, struct page *src, unsigned int dest_offset,
  46         unsigned int src_offset, size_t len, enum async_tx_flags flags,
  47         struct dma_async_tx_descriptor *depend_tx,
  48         dma_async_tx_callback cb_fn, void *cb_param)
  49 {
  50         struct dma_chan *chan = async_tx_find_channel(depend_tx, DMA_MEMCPY);
  51         struct dma_device *device = chan ? chan->device : NULL;
  52         int int_en = cb_fn ? 1 : 0;
  53         struct dma_async_tx_descriptor *tx = device ?
  54                 device->device_prep_dma_memcpy(chan, len,
  55                 int_en) : NULL;
  56
  57         if (tx) { /* run the memcpy asynchronously */
  58                 dma_addr_t addr;
  59                 enum dma_data_direction dir;
  60
  61                 pr_debug("%s: (async) len: %zu\n", __FUNCTION__, len);
  62
  63                 dir = (flags & ASYNC_TX_ASSUME_COHERENT) ?
  64                         DMA_NONE : DMA_FROM_DEVICE;
  65
  66                 addr = dma_map_page(device->dev, dest, dest_offset, len, dir);
  67                 tx->tx_set_dest(addr, tx, 0);
  68
  69                 dir = (flags & ASYNC_TX_ASSUME_COHERENT) ?
  70                         DMA_NONE : DMA_TO_DEVICE;
  71
  72                 addr = dma_map_page(device->dev, src, src_offset, len, dir);
  73                 tx->tx_set_src(addr, tx, 0);
  74
  75                 async_tx_submit(chan, tx, flags, depend_tx, cb_fn, cb_param);
  76         } else { /* run the memcpy synchronously */
  77                 void *dest_buf, *src_buf;
  78                 pr_debug("%s: (sync) len: %zu\n", __FUNCTION__, len);
  79
  80                 /* wait for any prerequisite operations */
  81                 if (depend_tx) {
  82                         /* if ack is already set then we cannot be sure
  83                          * we are referring to the correct operation
  84                          */
  85                         BUG_ON(depend_tx->ack);
  86                         if (dma_wait_for_async_tx(depend_tx) == DMA_ERROR)
  87                                 panic("%s: DMA_ERROR waiting for depend_tx\n",
  88                                         __FUNCTION__);
  89                 }
  90
  91                 if (flags & ASYNC_TX_KMAP_DST)
  92                         dest_buf = kmap_atomic(dest, KM_USER0) + dest_offset;
  93                 else
  94                         dest_buf = page_address(dest) + dest_offset;
  95
  96                 if (flags & ASYNC_TX_KMAP_SRC)
  97                         src_buf = kmap_atomic(src, KM_USER0) + src_offset;
  98                 else
  99                         src_buf = page_address(src) + src_offset;
 100
 101                 memcpy(dest_buf, src_buf, len);
 102
 103                 if (flags & ASYNC_TX_KMAP_DST)
 104                         kunmap_atomic(dest_buf, KM_USER0);
 105
 106                 if (flags & ASYNC_TX_KMAP_SRC)
 107                         kunmap_atomic(src_buf, KM_USER0);
 108
 109                 async_tx_sync_epilog(flags, depend_tx, cb_fn, cb_param);
 110         }
 111
 112         return tx;
 113 }
 114 EXPORT_SYMBOL_GPL(async_memcpy);
 115
 116 static int __init async_memcpy_init(void)
 117 {
 118         return 0;
 119 }
 120
 121 static void __exit async_memcpy_exit(void)
 122 {
 123         do { } while (0);
 124 }
 125
 126 module_init(async_memcpy_init);
 127 module_exit(async_memcpy_exit);
 128
 129 MODULE_AUTHOR("Intel Corporation");
 130 MODULE_DESCRIPTION("asynchronous memcpy api");
 131 MODULE_LICENSE("GPL");