dmaengine: refactor dmaengine around dma_async_tx_descriptor

The current dmaengine interface defines mutliple routines per operation,
i.e. dma_async_memcpy_buf_to_buf, dma_async_memcpy_buf_to_page etc.  Adding
more operation types (xor, crc, etc) to this model would result in an
unmanageable number of method permutations.

	Are we really going to add a set of hooks for each DMA engine
	whizbang feature?
		- Jeff Garzik

The descriptor creation process is refactored using the new common
dma_async_tx_descriptor structure.  Instead of per driver
do_<operation>_<dest>_to_<src> methods, drivers integrate
dma_async_tx_descriptor into their private software descriptor and then
define a 'prep' routine per operation.  The prep routine allocates a
descriptor and ensures that the tx_set_src, tx_set_dest, tx_submit routines
are valid.  Descriptor creation and submission becomes:

struct dma_device *dev;
struct dma_chan *chan;
struct dma_async_tx_descriptor *tx;

tx = dev->device_prep_dma_<operation>(chan, len, int_flag)
tx->tx_set_src(dma_addr_t, tx, index /* for multi-source ops */)
tx->tx_set_dest(dma_addr_t, tx, index)
tx->tx_submit(tx)

In addition to the refactoring, dma_async_tx_descriptor also lays the
groundwork for definining cross-channel-operation dependencies, and a
callback facility for asynchronous notification of operation completion.

Changelog:
* drop dma mapping methods, suggested by Chris Leech
* fix ioat_dma_dependency_added, also caught by Andrew Morton
* fix dma_sync_wait, change from Andrew Morton
* uninline large functions, change from Andrew Morton
* add tx->callback = NULL to dmaengine calls to interoperate with async_tx
  calls
* hookup ioat_tx_submit
* convert channel capabilities to a 'cpumask_t like' bitmap
* removed DMA_TX_ARRAY_INIT, no longer needed
* checkpatch.pl fixes
* make set_src, set_dest, and tx_submit descriptor specific methods
* fixup git-ioat merge
* move group_list and phys to dma_async_tx_descriptor

Cc: Jeff Garzik <jeff@garzik.org>
Cc: Chris Leech <christopher.leech@intel.com>
Signed-off-by: Shannon Nelson <shannon.nelson@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Acked-by: David S. Miller <davem@davemloft.net>

1 files changed, 6 insertions, 7 deletions

diff --git a/drivers/dma/ioatdma.h b/drivers/dma/ioatdma.h
index 62b26a9be4c9..d3f69bb15fa0 100644
--- a/drivers/dma/ioatdma.h
+++ b/drivers/dma/ioatdma.h
@@ -105,21 +105,20 @@ struct ioat_dma_chan {
 /**
  * struct ioat_desc_sw - wrapper around hardware descriptor
  * @hw: hardware DMA descriptor
- * @node:
- * @cookie:
- * @phys:
+ * @node: this descriptor will either be on the free list,
+ *     or attached to a transaction list (async_tx.tx_list)
+ * @tx_cnt: number of descriptors required to complete the transaction
+ * @async_tx: the generic software descriptor for all engines
  */
-
 struct ioat_desc_sw {
         struct ioat_dma_descriptor *hw;
         struct list_head node;
-        dma_cookie_t cookie;
-        dma_addr_t phys;
+        int tx_cnt;
         DECLARE_PCI_UNMAP_ADDR(src)
         DECLARE_PCI_UNMAP_LEN(src_len)
         DECLARE_PCI_UNMAP_ADDR(dst)
         DECLARE_PCI_UNMAP_LEN(dst_len)
+        struct dma_async_tx_descriptor async_tx;
 };
 
 #endif /* IOATDMA_H */
-