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staging: fsl-dpaa2/eth: Make Tx buffer alignment optional

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Aligning the Tx buffers at 64B is a performance optimization
recommendation, not a hard requirement.

Make optional the alignment of Tx FD buffers, without enforcing
a reallocation in case there is not enough headroom for it.

On Rx, we keep allocating buffers with enough headroom to allow
Tx alignment of forwarded frames.

Signed-off-by: Ioana Radulescu <ruxandra.radulescu@nxp.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Ioana Radulescu 2017-12-08 06:47:58 -06:00 committed by Greg Kroah-Hartman
parent 18c21467b2
commit c163685fc8
2 changed files with 11 additions and 5 deletions
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14
drivers/staging/fsl-dpaa2/ethernet/dpaa2-eth.c
View file

@ -433,13 +433,19 @@ static int build_single_fd(struct dpaa2_eth_priv *priv,
struct dpaa2_fd *fd)
{
struct device *dev = priv->net_dev->dev.parent;
u8 *buffer_start;
u8 *buffer_start, *aligned_start;
struct sk_buff **skbh;
dma_addr_t addr;
buffer_start = PTR_ALIGN(skb->data -
dpaa2_eth_needed_headroom(priv, skb),
DPAA2_ETH_TX_BUF_ALIGN);
buffer_start = skb->data - dpaa2_eth_needed_headroom(priv, skb);
/* If there's enough room to align the FD address, do it.
* It will help hardware optimize accesses.
*/
aligned_start = PTR_ALIGN(buffer_start - DPAA2_ETH_TX_BUF_ALIGN,
DPAA2_ETH_TX_BUF_ALIGN);
if (aligned_start >= skb->head)
buffer_start = aligned_start;
/* Store a backpointer to the skb at the beginning of the buffer
* (in the private data area) such that we can release it

2
drivers/staging/fsl-dpaa2/ethernet/dpaa2-eth.h
View file

@ -370,7 +370,7 @@ unsigned int dpaa2_eth_needed_headroom(struct dpaa2_eth_priv *priv,
if (skb_is_nonlinear(skb))
return 0;
return DPAA2_ETH_SWA_SIZE + DPAA2_ETH_TX_BUF_ALIGN;
return DPAA2_ETH_SWA_SIZE;
}
/* Extra headroom space requested to hardware, in order to make sure there's