[PATCH v2 1/2] net: thunderx: HW TSO support for pass-2 hardware

From: Sunil Goutham
Date: Thu Dec 10 2015 - 02:53:58 EST


From: Sunil Goutham <sgoutham@xxxxxxxxxx>

This adds support for offloading TCP segmentation to HW in pass-2
revision of hardware. Both driver level SW TSO for pass1.x chips
and HW TSO for pass-2 chip will co-exist. Modified SQ descriptor
structures to reflect pass-2 hw implementation.

Signed-off-by: Sunil Goutham <sgoutham@xxxxxxxxxx>
---
drivers/net/ethernet/cavium/thunder/nic.h | 6 ++++
drivers/net/ethernet/cavium/thunder/nic_main.c | 11 ++-----
drivers/net/ethernet/cavium/thunder/nicvf_main.c | 15 ++++++++-
drivers/net/ethernet/cavium/thunder/nicvf_queues.c | 20 ++++++++++---
drivers/net/ethernet/cavium/thunder/q_struct.h | 30 ++++++++++---------
5 files changed, 53 insertions(+), 29 deletions(-)

diff --git a/drivers/net/ethernet/cavium/thunder/nic.h b/drivers/net/ethernet/cavium/thunder/nic.h
index 39ca674..6888288 100644
--- a/drivers/net/ethernet/cavium/thunder/nic.h
+++ b/drivers/net/ethernet/cavium/thunder/nic.h
@@ -265,6 +265,7 @@ struct nicvf {
u8 tns_mode:1;
u8 sqs_mode:1;
u8 loopback_supported:1;
+ bool hw_tso;
u16 mtu;
struct queue_set *qs;
#define MAX_SQS_PER_VF_SINGLE_NODE 5
@@ -489,6 +490,11 @@ static inline int nic_get_node_id(struct pci_dev *pdev)
return ((addr >> NIC_NODE_ID_SHIFT) & NIC_NODE_ID_MASK);
}

+static inline bool pass1_silicon(struct pci_dev *pdev)
+{
+ return pdev->revision < 8;
+}
+
int nicvf_set_real_num_queues(struct net_device *netdev,
int tx_queues, int rx_queues);
int nicvf_open(struct net_device *netdev);
diff --git a/drivers/net/ethernet/cavium/thunder/nic_main.c b/drivers/net/ethernet/cavium/thunder/nic_main.c
index 4b7fd63..9f80de4 100644
--- a/drivers/net/ethernet/cavium/thunder/nic_main.c
+++ b/drivers/net/ethernet/cavium/thunder/nic_main.c
@@ -55,11 +55,6 @@ struct nicpf {
bool irq_allocated[NIC_PF_MSIX_VECTORS];
};

-static inline bool pass1_silicon(struct nicpf *nic)
-{
- return nic->pdev->revision < 8;
-}
-
/* Supported devices */
static const struct pci_device_id nic_id_table[] = {
{ PCI_DEVICE(PCI_VENDOR_ID_CAVIUM, PCI_DEVICE_ID_THUNDER_NIC_PF) },
@@ -123,7 +118,7 @@ static void nic_send_msg_to_vf(struct nicpf *nic, int vf, union nic_mbx *mbx)
* when PF writes to MBOX(1), in next revisions when
* PF writes to MBOX(0)
*/
- if (pass1_silicon(nic)) {
+ if (pass1_silicon(nic->pdev)) {
/* see the comment for nic_reg_write()/nic_reg_read()
* functions above
*/
@@ -400,7 +395,7 @@ static void nic_config_cpi(struct nicpf *nic, struct cpi_cfg_msg *cfg)
padd = cpi % 8; /* 3 bits CS out of 6bits DSCP */

/* Leave RSS_SIZE as '0' to disable RSS */
- if (pass1_silicon(nic)) {
+ if (pass1_silicon(nic->pdev)) {
nic_reg_write(nic, NIC_PF_CPI_0_2047_CFG | (cpi << 3),
(vnic << 24) | (padd << 16) |
(rssi_base + rssi));
@@ -470,7 +465,7 @@ static void nic_config_rss(struct nicpf *nic, struct rss_cfg_msg *cfg)
}

cpi_base = nic->cpi_base[cfg->vf_id];
- if (pass1_silicon(nic))
+ if (pass1_silicon(nic->pdev))
idx_addr = NIC_PF_CPI_0_2047_CFG;
else
idx_addr = NIC_PF_MPI_0_2047_CFG;
diff --git a/drivers/net/ethernet/cavium/thunder/nicvf_main.c b/drivers/net/ethernet/cavium/thunder/nicvf_main.c
index dde8dc7..c24cb2a 100644
--- a/drivers/net/ethernet/cavium/thunder/nicvf_main.c
+++ b/drivers/net/ethernet/cavium/thunder/nicvf_main.c
@@ -525,14 +525,22 @@ static void nicvf_snd_pkt_handler(struct net_device *netdev,
__func__, cqe_tx->sq_qs, cqe_tx->sq_idx,
cqe_tx->sqe_ptr, hdr->subdesc_cnt);

- nicvf_put_sq_desc(sq, hdr->subdesc_cnt + 1);
nicvf_check_cqe_tx_errs(nic, cq, cqe_tx);
skb = (struct sk_buff *)sq->skbuff[cqe_tx->sqe_ptr];
- /* For TSO offloaded packets only one head SKB needs to be freed */
+ /* For TSO offloaded packets only one SQE will have a valid SKB */
if (skb) {
+ nicvf_put_sq_desc(sq, hdr->subdesc_cnt + 1);
prefetch(skb);
dev_consume_skb_any(skb);
sq->skbuff[cqe_tx->sqe_ptr] = (u64)NULL;
+ } else {
+ /* In case of HW TSO, HW sends a CQE for each segment of a TSO
+ * packet instead of a single CQE for the whole TSO packet
+ * transmitted. Each of this CQE points to the same SQE, so
+ * avoid freeing same SQE multiple times.
+ */
+ if (!nic->hw_tso)
+ nicvf_put_sq_desc(sq, hdr->subdesc_cnt + 1);
}
}

@@ -1549,6 +1557,9 @@ static int nicvf_probe(struct pci_dev *pdev, const struct pci_device_id *ent)

netdev->vlan_features = NETIF_F_SG | NETIF_F_IP_CSUM | NETIF_F_TSO;

+ if (!pass1_silicon(nic->pdev))
+ nic->hw_tso = true;
+
netdev->netdev_ops = &nicvf_netdev_ops;
netdev->watchdog_timeo = NICVF_TX_TIMEOUT;

diff --git a/drivers/net/ethernet/cavium/thunder/nicvf_queues.c b/drivers/net/ethernet/cavium/thunder/nicvf_queues.c
index 1fbd908..b11fc09 100644
--- a/drivers/net/ethernet/cavium/thunder/nicvf_queues.c
+++ b/drivers/net/ethernet/cavium/thunder/nicvf_queues.c
@@ -925,7 +925,7 @@ static int nicvf_sq_subdesc_required(struct nicvf *nic, struct sk_buff *skb)
{
int subdesc_cnt = MIN_SQ_DESC_PER_PKT_XMIT;

- if (skb_shinfo(skb)->gso_size) {
+ if (skb_shinfo(skb)->gso_size && !nic->hw_tso) {
subdesc_cnt = nicvf_tso_count_subdescs(skb);
return subdesc_cnt;
}
@@ -940,7 +940,7 @@ static int nicvf_sq_subdesc_required(struct nicvf *nic, struct sk_buff *skb)
* First subdescriptor for every send descriptor.
*/
static inline void
-nicvf_sq_add_hdr_subdesc(struct snd_queue *sq, int qentry,
+nicvf_sq_add_hdr_subdesc(struct nicvf *nic, struct snd_queue *sq, int qentry,
int subdesc_cnt, struct sk_buff *skb, int len)
{
int proto;
@@ -976,6 +976,15 @@ nicvf_sq_add_hdr_subdesc(struct snd_queue *sq, int qentry,
break;
}
}
+
+ if (nic->hw_tso && skb_shinfo(skb)->gso_size) {
+ hdr->tso = 1;
+ hdr->tso_start = skb_transport_offset(skb) + tcp_hdrlen(skb);
+ hdr->tso_max_paysize = skb_shinfo(skb)->gso_size;
+ /* For non-tunneled pkts, point this to L2 ethertype */
+ hdr->inner_l3_offset = skb_network_offset(skb) - 2;
+ nic->drv_stats.tx_tso++;
+ }
}

/* SQ GATHER subdescriptor
@@ -1045,7 +1054,7 @@ static int nicvf_sq_append_tso(struct nicvf *nic, struct snd_queue *sq,
data_left -= size;
tso_build_data(skb, &tso, size);
}
- nicvf_sq_add_hdr_subdesc(sq, hdr_qentry,
+ nicvf_sq_add_hdr_subdesc(nic, sq, hdr_qentry,
seg_subdescs - 1, skb, seg_len);
sq->skbuff[hdr_qentry] = (u64)NULL;
qentry = nicvf_get_nxt_sqentry(sq, qentry);
@@ -1098,11 +1107,12 @@ int nicvf_sq_append_skb(struct nicvf *nic, struct sk_buff *skb)
qentry = nicvf_get_sq_desc(sq, subdesc_cnt);

/* Check if its a TSO packet */
- if (skb_shinfo(skb)->gso_size)
+ if (skb_shinfo(skb)->gso_size && !nic->hw_tso)
return nicvf_sq_append_tso(nic, sq, sq_num, qentry, skb);

/* Add SQ header subdesc */
- nicvf_sq_add_hdr_subdesc(sq, qentry, subdesc_cnt - 1, skb, skb->len);
+ nicvf_sq_add_hdr_subdesc(nic, sq, qentry, subdesc_cnt - 1,
+ skb, skb->len);

/* Add SQ gather subdescs */
qentry = nicvf_get_nxt_sqentry(sq, qentry);
diff --git a/drivers/net/ethernet/cavium/thunder/q_struct.h b/drivers/net/ethernet/cavium/thunder/q_struct.h
index 3c1de97..9e6d987 100644
--- a/drivers/net/ethernet/cavium/thunder/q_struct.h
+++ b/drivers/net/ethernet/cavium/thunder/q_struct.h
@@ -545,25 +545,28 @@ struct sq_hdr_subdesc {
u64 subdesc_cnt:8;
u64 csum_l4:2;
u64 csum_l3:1;
- u64 rsvd0:5;
+ u64 csum_inner_l4:2;
+ u64 csum_inner_l3:1;
+ u64 rsvd0:2;
u64 l4_offset:8;
u64 l3_offset:8;
u64 rsvd1:4;
u64 tot_len:20; /* W0 */

- u64 tso_sdc_cont:8;
- u64 tso_sdc_first:8;
- u64 tso_l4_offset:8;
- u64 tso_flags_last:12;
- u64 tso_flags_first:12;
- u64 rsvd2:2;
+ u64 rsvd2:24;
+ u64 inner_l4_offset:8;
+ u64 inner_l3_offset:8;
+ u64 tso_start:8;
+ u64 rsvd3:2;
u64 tso_max_paysize:14; /* W1 */
#elif defined(__LITTLE_ENDIAN_BITFIELD)
u64 tot_len:20;
u64 rsvd1:4;
u64 l3_offset:8;
u64 l4_offset:8;
- u64 rsvd0:5;
+ u64 rsvd0:2;
+ u64 csum_inner_l3:1;
+ u64 csum_inner_l4:2;
u64 csum_l3:1;
u64 csum_l4:2;
u64 subdesc_cnt:8;
@@ -574,12 +577,11 @@ struct sq_hdr_subdesc {
u64 subdesc_type:4; /* W0 */

u64 tso_max_paysize:14;
- u64 rsvd2:2;
- u64 tso_flags_first:12;
- u64 tso_flags_last:12;
- u64 tso_l4_offset:8;
- u64 tso_sdc_first:8;
- u64 tso_sdc_cont:8; /* W1 */
+ u64 rsvd3:2;
+ u64 tso_start:8;
+ u64 inner_l3_offset:8;
+ u64 inner_l4_offset:8;
+ u64 rsvd2:24; /* W1 */
#endif
};

--
1.7.1

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