diff options
| author | Sergei Shtylyov <sergei.shtylyov@cogentembedded.com> | 2015-07-25 23:42:01 +0300 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2015-07-27 01:22:38 -0700 |
| commit | 2f45d1902acfc7e6680cfeeb38922dcc7e16deb6 (patch) | |
| tree | 5d65107c25abf0912aacc61ea3ecb97796a2f464 /drivers/net/ethernet/renesas/ravb.h | |
| parent | c22995c5488d7048554d85ee5ee8a269932b0aea (diff) | |
ravb: minimize TX data copying
Renesas Ethernet AVB controller requires that all data are aligned on 4-byte
boundary. While it's easily achievable for the RX data with the help of
skb_reserve() (we even align on 128-byte boundary as recommended by the manual),
we can't do the same with the TX data, and it always comes unaligned from
the networking core. Originally we solved it an easy way, copying all packet
to a preallocated aligned buffer; however, it's enough to copy only up to
3 first bytes from each packet, doing the transfer using 2 TX descriptors
instead of just 1. Here's an implementation of the new TX algorithm that
significantly reduces the driver's memory requirements.
Signed-off-by: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/net/ethernet/renesas/ravb.h')
| -rw-r--r-- | drivers/net/ethernet/renesas/ravb.h | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/drivers/net/ethernet/renesas/ravb.h b/drivers/net/ethernet/renesas/ravb.h index 8aa50ac4e2d6..a157aaaaff6a 100644 --- a/drivers/net/ethernet/renesas/ravb.h +++ b/drivers/net/ethernet/renesas/ravb.h @@ -658,6 +658,8 @@ struct ravb_desc { __le32 dptr; /* Descriptor pointer */ }; +#define DPTR_ALIGN 4 /* Required descriptor pointer alignment */ + enum DIE_DT { /* Frame data */ DT_FMID = 0x40, @@ -739,6 +741,7 @@ enum RAVB_QUEUE { #define RX_QUEUE_OFFSET 4 #define NUM_RX_QUEUE 2 #define NUM_TX_QUEUE 2 +#define NUM_TX_DESC 2 /* TX descriptors per packet */ struct ravb_tstamp_skb { struct list_head list; @@ -777,9 +780,9 @@ struct ravb_private { dma_addr_t tx_desc_dma[NUM_TX_QUEUE]; struct ravb_ex_rx_desc *rx_ring[NUM_RX_QUEUE]; struct ravb_tx_desc *tx_ring[NUM_TX_QUEUE]; + void *tx_align[NUM_TX_QUEUE]; struct sk_buff **rx_skb[NUM_RX_QUEUE]; struct sk_buff **tx_skb[NUM_TX_QUEUE]; - void **tx_buffers[NUM_TX_QUEUE]; u32 rx_over_errors; u32 rx_fifo_errors; struct net_device_stats stats[NUM_RX_QUEUE]; |