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bnxt_en: Fix implementation of tx push operation. 

tx push is supported for small packets to reduce DMA latency.  The
following bugs are fixed in this patch:

1. Fix the definition of the push BD which is different from the DMA BD.
2. The push buffer has to be zero padded to the next 64-bit word boundary
or tx checksum won't be correct.
3. Increase the tx push packet threshold to 164 bytes (192 bytes with the BD)
so that small tunneled packets are within the threshold.

Signed-off-by: Michael Chan <mchan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Michael Chan 2016-02-10 17:33:49 -05:00 committed by David S. Miller
parent 1c49c421f3
commit 4419dbe6a0
2 changed files with 34 additions and 19 deletions
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42
drivers/net/ethernet/broadcom/bnxt/bnxt.c
View File

@ -69,7 +69,7 @@ MODULE_VERSION(DRV_MODULE_VERSION);
#define BNXT_RX_DMA_OFFSET NET_SKB_PAD #define BNXT_RX_DMA_OFFSET NET_SKB_PAD
#define BNXT_RX_COPY_THRESH 256 #define BNXT_RX_COPY_THRESH 256
#define BNXT_TX_PUSH_THRESH 92 #define BNXT_TX_PUSH_THRESH 164
enum board_idx { enum board_idx {
BCM57301, BCM57301,
@ -223,11 +223,12 @@ static netdev_tx_t bnxt_start_xmit(struct sk_buff *skb, struct net_device *dev)
} }
if (free_size == bp->tx_ring_size && length <= bp->tx_push_thresh) { if (free_size == bp->tx_ring_size && length <= bp->tx_push_thresh) {
struct tx_push_bd *push = txr->tx_push; struct tx_push_buffer *tx_push_buf = txr->tx_push;
struct tx_bd *tx_push = &push->txbd1; struct tx_push_bd *tx_push = &tx_push_buf->push_bd;
struct tx_bd_ext *tx_push1 = &push->txbd2; struct tx_bd_ext *tx_push1 = &tx_push->txbd2;
void *pdata = tx_push1 + 1; void *pdata = tx_push_buf->data;
int j; u64 *end;
int j, push_len;
/* Set COAL_NOW to be ready quickly for the next push */ /* Set COAL_NOW to be ready quickly for the next push */
tx_push->tx_bd_len_flags_type = tx_push->tx_bd_len_flags_type =
@ -247,6 +248,9 @@ static netdev_tx_t bnxt_start_xmit(struct sk_buff *skb, struct net_device *dev)
tx_push1->tx_bd_cfa_meta = cpu_to_le32(vlan_tag_flags); tx_push1->tx_bd_cfa_meta = cpu_to_le32(vlan_tag_flags);
tx_push1->tx_bd_cfa_action = cpu_to_le32(cfa_action); tx_push1->tx_bd_cfa_action = cpu_to_le32(cfa_action);
end = PTR_ALIGN(pdata + length + 1, 8) - 1;
*end = 0;
skb_copy_from_linear_data(skb, pdata, len); skb_copy_from_linear_data(skb, pdata, len);
pdata += len; pdata += len;
for (j = 0; j < last_frag; j++) { for (j = 0; j < last_frag; j++) {
@ -261,22 +265,29 @@ static netdev_tx_t bnxt_start_xmit(struct sk_buff *skb, struct net_device *dev)
pdata += skb_frag_size(frag); pdata += skb_frag_size(frag);
} }
memcpy(txbd, tx_push, sizeof(*txbd)); txbd->tx_bd_len_flags_type = tx_push->tx_bd_len_flags_type;
txbd->tx_bd_haddr = txr->data_mapping;
prod = NEXT_TX(prod); prod = NEXT_TX(prod);
txbd = &txr->tx_desc_ring[TX_RING(prod)][TX_IDX(prod)]; txbd = &txr->tx_desc_ring[TX_RING(prod)][TX_IDX(prod)];
memcpy(txbd, tx_push1, sizeof(*txbd)); memcpy(txbd, tx_push1, sizeof(*txbd));
prod = NEXT_TX(prod); prod = NEXT_TX(prod);
push->doorbell = tx_push->doorbell =
cpu_to_le32(DB_KEY_TX_PUSH | DB_LONG_TX_PUSH | prod); cpu_to_le32(DB_KEY_TX_PUSH | DB_LONG_TX_PUSH | prod);
txr->tx_prod = prod; txr->tx_prod = prod;
netdev_tx_sent_queue(txq, skb->len); netdev_tx_sent_queue(txq, skb->len);
__iowrite64_copy(txr->tx_doorbell, push, push_len = (length + sizeof(*tx_push) + 7) / 8;
(length + sizeof(*push) + 8) / 8); if (push_len > 16) {
__iowrite64_copy(txr->tx_doorbell, tx_push_buf, 16);
__iowrite64_copy(txr->tx_doorbell + 4, tx_push_buf + 1,
push_len - 16);
} else {
__iowrite64_copy(txr->tx_doorbell, tx_push_buf,
push_len);
}
tx_buf->is_push = 1; tx_buf->is_push = 1;
goto tx_done; goto tx_done;
} }
@ -1753,7 +1764,7 @@ static int bnxt_alloc_tx_rings(struct bnxt *bp)
push_size = L1_CACHE_ALIGN(sizeof(struct tx_push_bd) + push_size = L1_CACHE_ALIGN(sizeof(struct tx_push_bd) +
bp->tx_push_thresh); bp->tx_push_thresh);
if (push_size > 128) { if (push_size > 256) {
push_size = 0; push_size = 0;
bp->tx_push_thresh = 0; bp->tx_push_thresh = 0;
} }
@ -1772,7 +1783,6 @@ static int bnxt_alloc_tx_rings(struct bnxt *bp)
return rc; return rc;
if (bp->tx_push_size) { if (bp->tx_push_size) {
struct tx_bd *txbd;
dma_addr_t mapping; dma_addr_t mapping;
/* One pre-allocated DMA buffer to backup /* One pre-allocated DMA buffer to backup
@ -1786,13 +1796,11 @@ static int bnxt_alloc_tx_rings(struct bnxt *bp)
if (!txr->tx_push) if (!txr->tx_push)
return -ENOMEM; return -ENOMEM;
txbd = &txr->tx_push->txbd1;
mapping = txr->tx_push_mapping + mapping = txr->tx_push_mapping +
sizeof(struct tx_push_bd); sizeof(struct tx_push_bd);
txbd->tx_bd_haddr = cpu_to_le64(mapping); txr->data_mapping = cpu_to_le64(mapping);
memset(txbd + 1, 0, sizeof(struct tx_bd_ext)); memset(txr->tx_push, 0, sizeof(struct tx_push_bd));
} }
ring->queue_id = bp->q_info[j].queue_id; ring->queue_id = bp->q_info[j].queue_id;
if (i % bp->tx_nr_rings_per_tc == (bp->tx_nr_rings_per_tc - 1)) if (i % bp->tx_nr_rings_per_tc == (bp->tx_nr_rings_per_tc - 1))

11
drivers/net/ethernet/broadcom/bnxt/bnxt.h
View File

@ -523,10 +523,16 @@ struct bnxt_ring_struct {
struct tx_push_bd { struct tx_push_bd {
__le32 doorbell; __le32 doorbell;
struct tx_bd txbd1; __le32 tx_bd_len_flags_type;
u32 tx_bd_opaque;
struct tx_bd_ext txbd2; struct tx_bd_ext txbd2;
}; };
struct tx_push_buffer {
struct tx_push_bd push_bd;
u32 data[25];
};
struct bnxt_tx_ring_info { struct bnxt_tx_ring_info {
struct bnxt_napi *bnapi; struct bnxt_napi *bnapi;
u16 tx_prod; u16 tx_prod;
@ -538,8 +544,9 @@ struct bnxt_tx_ring_info {
dma_addr_t tx_desc_mapping[MAX_TX_PAGES]; dma_addr_t tx_desc_mapping[MAX_TX_PAGES];
struct tx_push_bd *tx_push; struct tx_push_buffer *tx_push;
dma_addr_t tx_push_mapping; dma_addr_t tx_push_mapping;
__le64 data_mapping;
#define BNXT_DEV_STATE_CLOSING 0x1 #define BNXT_DEV_STATE_CLOSING 0x1
u32 dev_state; u32 dev_state;