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netxen: cut-through rx changes

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NX3031 supports cut-through operation where ingress packets are
directly dma'ed into host buffers to reduce latency.

This requires larger dma buffers (2kb) and different alignemnt.

The buffer posting logic is changed a bit. The free rx buffers
are maintained in linked list, since the received reference
handles can be out of order. However rx descriptors are still
posted sequentially, indexed by producer.

Signed-off-by: Dhananjay Phadke <dhananjay@netxen.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
This commit is contained in:
Dhananjay Phadke
2008-07-21 19:44:08 -07:00
committed by Jeff Garzik
parent c9fc891f86
commit d9e651bc06
4 changed files with 876 additions and 78 deletions
Download Patch File Download Diff File Expand all files Collapse all files

191
drivers/net/netxen/netxen_nic_init.c
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@@ -262,17 +262,30 @@ int netxen_alloc_sw_resources(struct netxen_adapter *adapter)
rds_ring->max_rx_desc_count =
adapter->max_rx_desc_count;
rds_ring->flags = RCV_DESC_NORMAL;
rds_ring->dma_size = RX_DMA_MAP_LEN;
rds_ring->skb_size = MAX_RX_BUFFER_LENGTH;
if (adapter->ahw.cut_through) {
rds_ring->dma_size =
NX_CT_DEFAULT_RX_BUF_LEN;
rds_ring->skb_size =
NX_CT_DEFAULT_RX_BUF_LEN;
} else {
rds_ring->dma_size = RX_DMA_MAP_LEN;
rds_ring->skb_size =
MAX_RX_BUFFER_LENGTH;
}
break;
case RCV_DESC_JUMBO:
rds_ring->max_rx_desc_count =
adapter->max_jumbo_rx_desc_count;
rds_ring->flags = RCV_DESC_JUMBO;
rds_ring->dma_size = RX_JUMBO_DMA_MAP_LEN;
if (NX_IS_REVISION_P3(adapter->ahw.revision_id))
rds_ring->dma_size =
NX_P3_RX_JUMBO_BUF_MAX_LEN;
else
rds_ring->dma_size =
NX_P2_RX_JUMBO_BUF_MAX_LEN;
rds_ring->skb_size =
MAX_RX_JUMBO_BUFFER_LENGTH;
rds_ring->dma_size + NET_IP_ALIGN;
break;
case RCV_RING_LRO:
@@ -294,6 +307,7 @@ int netxen_alloc_sw_resources(struct netxen_adapter *adapter)
goto err_out;
}
memset(rds_ring->rx_buf_arr, 0, RCV_BUFFSIZE);
INIT_LIST_HEAD(&rds_ring->free_list);
rds_ring->begin_alloc = 0;
/*
* Now go through all of them, set reference handles
@@ -302,6 +316,8 @@ int netxen_alloc_sw_resources(struct netxen_adapter *adapter)
num_rx_bufs = rds_ring->max_rx_desc_count;
rx_buf = rds_ring->rx_buf_arr;
for (i = 0; i < num_rx_bufs; i++) {
list_add_tail(&rx_buf->list,
&rds_ring->free_list);
rx_buf->ref_handle = i;
rx_buf->state = NETXEN_BUFFER_FREE;
rx_buf++;
@@ -1137,15 +1153,47 @@ int netxen_receive_peg_ready(struct netxen_adapter *adapter)
return 0;
}
static struct sk_buff *netxen_process_rxbuf(struct netxen_adapter *adapter,
struct nx_host_rds_ring *rds_ring, u16 index, u16 cksum)
{
struct netxen_rx_buffer *buffer;
struct sk_buff *skb;
buffer = &rds_ring->rx_buf_arr[index];
pci_unmap_single(adapter->pdev, buffer->dma, rds_ring->dma_size,
PCI_DMA_FROMDEVICE);
skb = buffer->skb;
if (!skb)
goto no_skb;
if (likely(adapter->rx_csum && cksum == STATUS_CKSUM_OK)) {
adapter->stats.csummed++;
skb->ip_summed = CHECKSUM_UNNECESSARY;
} else
skb->ip_summed = CHECKSUM_NONE;
skb->dev = adapter->netdev;
buffer->skb = NULL;
no_skb:
buffer->state = NETXEN_BUFFER_FREE;
buffer->lro_current_frags = 0;
buffer->lro_expected_frags = 0;
list_add_tail(&buffer->list, &rds_ring->free_list);
return skb;
}
/*
* netxen_process_rcv() send the received packet to the protocol stack.
* and if the number of receives exceeds RX_BUFFERS_REFILL, then we
* invoke the routine to send more rx buffers to the Phantom...
*/
static void netxen_process_rcv(struct netxen_adapter *adapter, int ctxid,
struct status_desc *desc)
struct status_desc *desc, struct status_desc *frag_desc)
{
struct pci_dev *pdev = adapter->pdev;
struct net_device *netdev = adapter->netdev;
u64 sts_data = le64_to_cpu(desc->status_desc_data);
int index = netxen_get_sts_refhandle(sts_data);
@@ -1154,8 +1202,8 @@ static void netxen_process_rcv(struct netxen_adapter *adapter, int ctxid,
struct sk_buff *skb;
u32 length = netxen_get_sts_totallength(sts_data);
u32 desc_ctx;
u16 pkt_offset = 0, cksum;
struct nx_host_rds_ring *rds_ring;
int ret;
desc_ctx = netxen_get_sts_type(sts_data);
if (unlikely(desc_ctx >= NUM_RCV_DESC_RINGS)) {
@@ -1191,41 +1239,52 @@ static void netxen_process_rcv(struct netxen_adapter *adapter, int ctxid,
}
}
pci_unmap_single(pdev, buffer->dma, rds_ring->dma_size,
PCI_DMA_FROMDEVICE);
cksum = netxen_get_sts_status(sts_data);
skb = (struct sk_buff *)buffer->skb;
skb = netxen_process_rxbuf(adapter, rds_ring, index, cksum);
if (!skb)
return;
if (likely(adapter->rx_csum &&
netxen_get_sts_status(sts_data) == STATUS_CKSUM_OK)) {
adapter->stats.csummed++;
skb->ip_summed = CHECKSUM_UNNECESSARY;
} else
skb->ip_summed = CHECKSUM_NONE;
skb->dev = netdev;
if (desc_ctx == RCV_DESC_LRO_CTXID) {
/* True length was only available on the last pkt */
skb_put(skb, buffer->lro_length);
} else {
skb_put(skb, length);
if (length > rds_ring->skb_size)
skb_put(skb, rds_ring->skb_size);
else
skb_put(skb, length);
pkt_offset = netxen_get_sts_pkt_offset(sts_data);
if (pkt_offset)
skb_pull(skb, pkt_offset);
}
skb->protocol = eth_type_trans(skb, netdev);
ret = netif_receive_skb(skb);
netdev->last_rx = jiffies;
/*
* We just consumed one buffer so post a buffer.
* rx buffer chaining is disabled, walk and free
* any spurious rx buffer chain.
*/
buffer->skb = NULL;
buffer->state = NETXEN_BUFFER_FREE;
buffer->lro_current_frags = 0;
buffer->lro_expected_frags = 0;
if (frag_desc) {
u16 i, nr_frags = desc->nr_frags;
adapter->stats.no_rcv++;
adapter->stats.rxbytes += length;
dev_kfree_skb_any(skb);
for (i = 0; i < nr_frags; i++) {
index = frag_desc->frag_handles[i];
skb = netxen_process_rxbuf(adapter,
rds_ring, index, cksum);
if (skb)
dev_kfree_skb_any(skb);
}
adapter->stats.rxdropped++;
} else {
netif_receive_skb(skb);
netdev->last_rx = jiffies;
adapter->stats.no_rcv++;
adapter->stats.rxbytes += length;
}
}
/* Process Receive status ring */
@@ -1233,9 +1292,11 @@ u32 netxen_process_rcv_ring(struct netxen_adapter *adapter, int ctxid, int max)
{
struct netxen_recv_context *recv_ctx = &(adapter->recv_ctx[ctxid]);
struct status_desc *desc_head = recv_ctx->rcv_status_desc_head;
struct status_desc *desc; /* used to read status desc here */
struct status_desc *desc, *frag_desc;
u32 consumer = recv_ctx->status_rx_consumer;
int count = 0, ring;
u64 sts_data;
u16 opcode;
while (count < max) {
desc = &desc_head[consumer];
@@ -1244,9 +1305,26 @@ u32 netxen_process_rcv_ring(struct netxen_adapter *adapter, int ctxid, int max)
netxen_get_sts_owner(desc));
break;
}
netxen_process_rcv(adapter, ctxid, desc);
sts_data = le64_to_cpu(desc->status_desc_data);
opcode = netxen_get_sts_opcode(sts_data);
frag_desc = NULL;
if (opcode == NETXEN_NIC_RXPKT_DESC) {
if (desc->nr_frags) {
consumer = get_next_index(consumer,
adapter->max_rx_desc_count);
frag_desc = &desc_head[consumer];
netxen_set_sts_owner(frag_desc,
STATUS_OWNER_PHANTOM);
}
}
netxen_process_rcv(adapter, ctxid, desc, frag_desc);
netxen_set_sts_owner(desc, STATUS_OWNER_PHANTOM);
consumer = (consumer + 1) & (adapter->max_rx_desc_count - 1);
consumer = get_next_index(consumer,
adapter->max_rx_desc_count);
count++;
}
for (ring = 0; ring < adapter->max_rds_rings; ring++)
@@ -1348,36 +1426,31 @@ void netxen_post_rx_buffers(struct netxen_adapter *adapter, u32 ctx, u32 ringid)
int index = 0;
netxen_ctx_msg msg = 0;
dma_addr_t dma;
struct list_head *head;
rds_ring = &recv_ctx->rds_rings[ringid];
producer = rds_ring->producer;
index = rds_ring->begin_alloc;
buffer = &rds_ring->rx_buf_arr[index];
head = &rds_ring->free_list;
/* We can start writing rx descriptors into the phantom memory. */
while (buffer->state == NETXEN_BUFFER_FREE) {
while (!list_empty(head)) {
skb = dev_alloc_skb(rds_ring->skb_size);
if (unlikely(!skb)) {
/*
* TODO
* We need to schedule the posting of buffers to the pegs.
*/
rds_ring->begin_alloc = index;
DPRINTK(ERR, "netxen_post_rx_buffers: "
" allocated only %d buffers\n", count);
break;
}
buffer = list_entry(head->next, struct netxen_rx_buffer, list);
list_del(&buffer->list);
count++; /* now there should be no failure */
pdesc = &rds_ring->desc_head[producer];
#if defined(XGB_DEBUG)
*(unsigned long *)(skb->head) = 0xc0debabe;
if (skb_is_nonlinear(skb)) {
printk("Allocated SKB @%p is nonlinear\n");
}
#endif
skb_reserve(skb, 2);
if (!adapter->ahw.cut_through)
skb_reserve(skb, 2);
/* This will be setup when we receive the
* buffer after it has been filled FSL TBD TBD
* skb->dev = netdev;
@@ -1395,7 +1468,6 @@ void netxen_post_rx_buffers(struct netxen_adapter *adapter, u32 ctx, u32 ringid)
producer =
get_next_index(producer, rds_ring->max_rx_desc_count);
index = get_next_index(index, rds_ring->max_rx_desc_count);
buffer = &rds_ring->rx_buf_arr[index];
}
/* if we did allocate buffers, then write the count to Phantom */
if (count) {
@@ -1439,32 +1511,29 @@ static void netxen_post_rx_buffers_nodb(struct netxen_adapter *adapter,
struct netxen_rx_buffer *buffer;
int count = 0;
int index = 0;
struct list_head *head;
rds_ring = &recv_ctx->rds_rings[ringid];
producer = rds_ring->producer;
index = rds_ring->begin_alloc;
buffer = &rds_ring->rx_buf_arr[index];
head = &rds_ring->free_list;
/* We can start writing rx descriptors into the phantom memory. */
while (buffer->state == NETXEN_BUFFER_FREE) {
while (!list_empty(head)) {
skb = dev_alloc_skb(rds_ring->skb_size);
if (unlikely(!skb)) {
/*
* We need to schedule the posting of buffers to the pegs.
*/
rds_ring->begin_alloc = index;
DPRINTK(ERR, "netxen_post_rx_buffers_nodb: "
" allocated only %d buffers\n", count);
break;
}
buffer = list_entry(head->next, struct netxen_rx_buffer, list);
list_del(&buffer->list);
count++; /* now there should be no failure */
pdesc = &rds_ring->desc_head[producer];
skb_reserve(skb, 2);
/*
* This will be setup when we receive the
* buffer after it has been filled
* skb->dev = netdev;
*/
if (!adapter->ahw.cut_through)
skb_reserve(skb, 2);
buffer->skb = skb;
buffer->state = NETXEN_BUFFER_BUSY;
buffer->dma = pci_map_single(pdev, skb->data,