From: Vinicius Costa Gomes vinicius.gomes@intel.com
[ Upstream commit db0b124f02ba68de6517ac303d431af220ccfe9f ]
The I225 hardware has a limitation that packets can only be scheduled in the [0, cycle-time] interval. So, scheduling a packet to the start of the next cycle doesn't usually work.
To overcome this, we use the Transmit Descriptor first flag to indicates that a packet should be the first packet (from a queue) in a cycle according to the section 7.5.2.9.3.4 The First Packet on Each QBV Cycle in Intel Discrete I225/6 User Manual.
But this only works if there was any packet from that queue during the current cycle, to avoid this issue, we issue an empty packet if that's not the case. Also require one more descriptor to be available, to take into account the empty packet that might be issued.
Test Setup:
Talker: Use l2_tai to generate the launchtime into packet load.
Listener: Use timedump.c to compute the delta between packet arrival and LaunchTime packet payload.
Test Result:
Before:
1666000610127300000,1666000610127300096,96,621273 1666000610127400000,1666000610127400192,192,621274 1666000610127500000,1666000610127500032,32,621275 1666000610127600000,1666000610127600128,128,621276 1666000610127700000,1666000610127700224,224,621277 1666000610127800000,1666000610127800064,64,621278 1666000610127900000,1666000610127900160,160,621279 1666000610128000000,1666000610128000000,0,621280 1666000610128100000,1666000610128100096,96,621281 1666000610128200000,1666000610128200192,192,621282 1666000610128300000,1666000610128300032,32,621283 1666000610128400000,1666000610128301056,-98944,621284 1666000610128500000,1666000610128302080,-197920,621285 1666000610128600000,1666000610128302848,-297152,621286 1666000610128700000,1666000610128303872,-396128,621287 1666000610128800000,1666000610128304896,-495104,621288 1666000610128900000,1666000610128305664,-594336,621289 1666000610129000000,1666000610128306688,-693312,621290 1666000610129100000,1666000610128307712,-792288,621291 1666000610129200000,1666000610128308480,-891520,621292 1666000610129300000,1666000610128309504,-990496,621293 1666000610129400000,1666000610128310528,-1089472,621294 1666000610129500000,1666000610128311296,-1188704,621295 1666000610129600000,1666000610128312320,-1287680,621296 1666000610129700000,1666000610128313344,-1386656,621297 1666000610129800000,1666000610128314112,-1485888,621298 1666000610129900000,1666000610128315136,-1584864,621299 1666000610130000000,1666000610128316160,-1683840,621300 1666000610130100000,1666000610128316928,-1783072,621301 1666000610130200000,1666000610128317952,-1882048,621302 1666000610130300000,1666000610128318976,-1981024,621303 1666000610130400000,1666000610128319744,-2080256,621304 1666000610130500000,1666000610128320768,-2179232,621305 1666000610130600000,1666000610128321792,-2278208,621306 1666000610130700000,1666000610128322816,-2377184,621307 1666000610130800000,1666000610128323584,-2476416,621308 1666000610130900000,1666000610128324608,-2575392,621309 1666000610131000000,1666000610128325632,-2674368,621310 1666000610131100000,1666000610128326400,-2773600,621311 1666000610131200000,1666000610128327424,-2872576,621312 1666000610131300000,1666000610128328448,-2971552,621313 1666000610131400000,1666000610128329216,-3070784,621314 1666000610131500000,1666000610131500032,32,621315 1666000610131600000,1666000610131600128,128,621316 1666000610131700000,1666000610131700224,224,621317
After:
1666073510646200000,1666073510646200064,64,2676462 1666073510646300000,1666073510646300160,160,2676463 1666073510646400000,1666073510646400256,256,2676464 1666073510646500000,1666073510646500096,96,2676465 1666073510646600000,1666073510646600192,192,2676466 1666073510646700000,1666073510646700032,32,2676467 1666073510646800000,1666073510646800128,128,2676468 1666073510646900000,1666073510646900224,224,2676469 1666073510647000000,1666073510647000064,64,2676470 1666073510647100000,1666073510647100160,160,2676471 1666073510647200000,1666073510647200256,256,2676472 1666073510647300000,1666073510647300096,96,2676473 1666073510647400000,1666073510647400192,192,2676474 1666073510647500000,1666073510647500032,32,2676475 1666073510647600000,1666073510647600128,128,2676476 1666073510647700000,1666073510647700224,224,2676477 1666073510647800000,1666073510647800064,64,2676478 1666073510647900000,1666073510647900160,160,2676479 1666073510648000000,1666073510648000000,0,2676480 1666073510648100000,1666073510648100096,96,2676481 1666073510648200000,1666073510648200192,192,2676482 1666073510648300000,1666073510648300032,32,2676483 1666073510648400000,1666073510648400128,128,2676484 1666073510648500000,1666073510648500224,224,2676485 1666073510648600000,1666073510648600064,64,2676486 1666073510648700000,1666073510648700160,160,2676487 1666073510648800000,1666073510648800000,0,2676488 1666073510648900000,1666073510648900096,96,2676489 1666073510649000000,1666073510649000192,192,2676490 1666073510649100000,1666073510649100032,32,2676491 1666073510649200000,1666073510649200128,128,2676492 1666073510649300000,1666073510649300224,224,2676493 1666073510649400000,1666073510649400064,64,2676494 1666073510649500000,1666073510649500160,160,2676495 1666073510649600000,1666073510649600000,0,2676496 1666073510649700000,1666073510649700096,96,2676497 1666073510649800000,1666073510649800192,192,2676498 1666073510649900000,1666073510649900032,32,2676499 1666073510650000000,1666073510650000128,128,2676500
Fixes: 82faa9b79950 ("igc: Add support for ETF offloading") Signed-off-by: Vinicius Costa Gomes vinicius.gomes@intel.com Co-developed-by: Aravindhan Gunasekaran aravindhan.gunasekaran@intel.com Signed-off-by: Aravindhan Gunasekaran aravindhan.gunasekaran@intel.com Co-developed-by: Muhammad Husaini Zulkifli muhammad.husaini.zulkifli@intel.com Signed-off-by: Muhammad Husaini Zulkifli muhammad.husaini.zulkifli@intel.com Signed-off-by: Malli C mallikarjuna.chilakala@intel.com Tested-by: Naama Meir naamax.meir@linux.intel.com Signed-off-by: Tony Nguyen anthony.l.nguyen@intel.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/net/ethernet/intel/igc/igc.h | 2 + drivers/net/ethernet/intel/igc/igc_defines.h | 2 + drivers/net/ethernet/intel/igc/igc_main.c | 176 ++++++++++++++++--- 3 files changed, 151 insertions(+), 29 deletions(-)
diff --git a/drivers/net/ethernet/intel/igc/igc.h b/drivers/net/ethernet/intel/igc/igc.h index a97bf7a5f1d6..970dd878d8a7 100644 --- a/drivers/net/ethernet/intel/igc/igc.h +++ b/drivers/net/ethernet/intel/igc/igc.h @@ -87,6 +87,8 @@ struct igc_ring { u8 queue_index; /* logical index of the ring*/ u8 reg_idx; /* physical index of the ring */ bool launchtime_enable; /* true if LaunchTime is enabled */ + ktime_t last_tx_cycle; /* end of the cycle with a launchtime transmission */ + ktime_t last_ff_cycle; /* Last cycle with an active first flag */
u32 start_time; u32 end_time; diff --git a/drivers/net/ethernet/intel/igc/igc_defines.h b/drivers/net/ethernet/intel/igc/igc_defines.h index 32f5fd684139..352b50d3881d 100644 --- a/drivers/net/ethernet/intel/igc/igc_defines.h +++ b/drivers/net/ethernet/intel/igc/igc_defines.h @@ -278,6 +278,8 @@ #define IGC_ADVTXD_L4LEN_SHIFT 8 /* Adv ctxt L4LEN shift */ #define IGC_ADVTXD_MSS_SHIFT 16 /* Adv ctxt MSS shift */
+#define IGC_ADVTXD_TSN_CNTX_FIRST 0x00000080 + /* Transmit Control */ #define IGC_TCTL_EN 0x00000002 /* enable Tx */ #define IGC_TCTL_PSP 0x00000008 /* pad short packets */ diff --git a/drivers/net/ethernet/intel/igc/igc_main.c b/drivers/net/ethernet/intel/igc/igc_main.c index 48192594d3d7..f4082ea7beaa 100644 --- a/drivers/net/ethernet/intel/igc/igc_main.c +++ b/drivers/net/ethernet/intel/igc/igc_main.c @@ -898,25 +898,118 @@ static int igc_write_mc_addr_list(struct net_device *netdev) return netdev_mc_count(netdev); }
-static __le32 igc_tx_launchtime(struct igc_adapter *adapter, ktime_t txtime) +static __le32 igc_tx_launchtime(struct igc_ring *ring, ktime_t txtime, + bool *first_flag, bool *insert_empty) { + struct igc_adapter *adapter = netdev_priv(ring->netdev); ktime_t cycle_time = adapter->cycle_time; ktime_t base_time = adapter->base_time; + ktime_t now = ktime_get_clocktai(); + ktime_t baset_est, end_of_cycle; u32 launchtime; + s64 n;
- /* FIXME: when using ETF together with taprio, we may have a - * case where 'delta' is larger than the cycle_time, this may - * cause problems if we don't read the current value of - * IGC_BASET, as the value writen into the launchtime - * descriptor field may be misinterpreted. + n = div64_s64(ktime_sub_ns(now, base_time), cycle_time); + + baset_est = ktime_add_ns(base_time, cycle_time * (n)); + end_of_cycle = ktime_add_ns(baset_est, cycle_time); + + if (ktime_compare(txtime, end_of_cycle) >= 0) { + if (baset_est != ring->last_ff_cycle) { + *first_flag = true; + ring->last_ff_cycle = baset_est; + + if (ktime_compare(txtime, ring->last_tx_cycle) > 0) + *insert_empty = true; + } + } + + /* Introducing a window at end of cycle on which packets + * potentially not honor launchtime. Window of 5us chosen + * considering software update the tail pointer and packets + * are dma'ed to packet buffer. */ - div_s64_rem(ktime_sub_ns(txtime, base_time), cycle_time, &launchtime); + if ((ktime_sub_ns(end_of_cycle, now) < 5 * NSEC_PER_USEC)) + netdev_warn(ring->netdev, "Packet with txtime=%llu may not be honoured\n", + txtime); + + ring->last_tx_cycle = end_of_cycle; + + launchtime = ktime_sub_ns(txtime, baset_est); + if (launchtime > 0) + div_s64_rem(launchtime, cycle_time, &launchtime); + else + launchtime = 0;
return cpu_to_le32(launchtime); }
+static int igc_init_empty_frame(struct igc_ring *ring, + struct igc_tx_buffer *buffer, + struct sk_buff *skb) +{ + unsigned int size; + dma_addr_t dma; + + size = skb_headlen(skb); + + dma = dma_map_single(ring->dev, skb->data, size, DMA_TO_DEVICE); + if (dma_mapping_error(ring->dev, dma)) { + netdev_err_once(ring->netdev, "Failed to map DMA for TX\n"); + return -ENOMEM; + } + + buffer->skb = skb; + buffer->protocol = 0; + buffer->bytecount = skb->len; + buffer->gso_segs = 1; + buffer->time_stamp = jiffies; + dma_unmap_len_set(buffer, len, skb->len); + dma_unmap_addr_set(buffer, dma, dma); + + return 0; +} + +static int igc_init_tx_empty_descriptor(struct igc_ring *ring, + struct sk_buff *skb, + struct igc_tx_buffer *first) +{ + union igc_adv_tx_desc *desc; + u32 cmd_type, olinfo_status; + int err; + + if (!igc_desc_unused(ring)) + return -EBUSY; + + err = igc_init_empty_frame(ring, first, skb); + if (err) + return err; + + cmd_type = IGC_ADVTXD_DTYP_DATA | IGC_ADVTXD_DCMD_DEXT | + IGC_ADVTXD_DCMD_IFCS | IGC_TXD_DCMD | + first->bytecount; + olinfo_status = first->bytecount << IGC_ADVTXD_PAYLEN_SHIFT; + + desc = IGC_TX_DESC(ring, ring->next_to_use); + desc->read.cmd_type_len = cpu_to_le32(cmd_type); + desc->read.olinfo_status = cpu_to_le32(olinfo_status); + desc->read.buffer_addr = cpu_to_le64(dma_unmap_addr(first, dma)); + + netdev_tx_sent_queue(txring_txq(ring), skb->len); + + first->next_to_watch = desc; + + ring->next_to_use++; + if (ring->next_to_use == ring->count) + ring->next_to_use = 0; + + return 0; +} + +#define IGC_EMPTY_FRAME_SIZE 60 + static void igc_tx_ctxtdesc(struct igc_ring *tx_ring, - struct igc_tx_buffer *first, + __le32 launch_time, bool first_flag, u32 vlan_macip_lens, u32 type_tucmd, u32 mss_l4len_idx) { @@ -935,26 +1028,17 @@ static void igc_tx_ctxtdesc(struct igc_ring *tx_ring, if (test_bit(IGC_RING_FLAG_TX_CTX_IDX, &tx_ring->flags)) mss_l4len_idx |= tx_ring->reg_idx << 4;
+ if (first_flag) + mss_l4len_idx |= IGC_ADVTXD_TSN_CNTX_FIRST; + context_desc->vlan_macip_lens = cpu_to_le32(vlan_macip_lens); context_desc->type_tucmd_mlhl = cpu_to_le32(type_tucmd); context_desc->mss_l4len_idx = cpu_to_le32(mss_l4len_idx); - - /* We assume there is always a valid Tx time available. Invalid times - * should have been handled by the upper layers. - */ - if (tx_ring->launchtime_enable) { - struct igc_adapter *adapter = netdev_priv(tx_ring->netdev); - ktime_t txtime = first->skb->tstamp; - - skb_txtime_consumed(first->skb); - context_desc->launch_time = igc_tx_launchtime(adapter, - txtime); - } else { - context_desc->launch_time = 0; - } + context_desc->launch_time = launch_time; }
-static void igc_tx_csum(struct igc_ring *tx_ring, struct igc_tx_buffer *first) +static void igc_tx_csum(struct igc_ring *tx_ring, struct igc_tx_buffer *first, + __le32 launch_time, bool first_flag) { struct sk_buff *skb = first->skb; u32 vlan_macip_lens = 0; @@ -994,7 +1078,8 @@ static void igc_tx_csum(struct igc_ring *tx_ring, struct igc_tx_buffer *first) vlan_macip_lens |= skb_network_offset(skb) << IGC_ADVTXD_MACLEN_SHIFT; vlan_macip_lens |= first->tx_flags & IGC_TX_FLAGS_VLAN_MASK;
- igc_tx_ctxtdesc(tx_ring, first, vlan_macip_lens, type_tucmd, 0); + igc_tx_ctxtdesc(tx_ring, launch_time, first_flag, + vlan_macip_lens, type_tucmd, 0); }
static int __igc_maybe_stop_tx(struct igc_ring *tx_ring, const u16 size) @@ -1218,6 +1303,7 @@ static int igc_tx_map(struct igc_ring *tx_ring,
static int igc_tso(struct igc_ring *tx_ring, struct igc_tx_buffer *first, + __le32 launch_time, bool first_flag, u8 *hdr_len) { u32 vlan_macip_lens, type_tucmd, mss_l4len_idx; @@ -1304,8 +1390,8 @@ static int igc_tso(struct igc_ring *tx_ring, vlan_macip_lens |= (ip.hdr - skb->data) << IGC_ADVTXD_MACLEN_SHIFT; vlan_macip_lens |= first->tx_flags & IGC_TX_FLAGS_VLAN_MASK;
- igc_tx_ctxtdesc(tx_ring, first, vlan_macip_lens, - type_tucmd, mss_l4len_idx); + igc_tx_ctxtdesc(tx_ring, launch_time, first_flag, + vlan_macip_lens, type_tucmd, mss_l4len_idx);
return 1; } @@ -1313,11 +1399,14 @@ static int igc_tso(struct igc_ring *tx_ring, static netdev_tx_t igc_xmit_frame_ring(struct sk_buff *skb, struct igc_ring *tx_ring) { + bool first_flag = false, insert_empty = false; u16 count = TXD_USE_COUNT(skb_headlen(skb)); __be16 protocol = vlan_get_protocol(skb); struct igc_tx_buffer *first; + __le32 launch_time = 0; u32 tx_flags = 0; unsigned short f; + ktime_t txtime; u8 hdr_len = 0; int tso = 0;
@@ -1331,11 +1420,40 @@ static netdev_tx_t igc_xmit_frame_ring(struct sk_buff *skb, count += TXD_USE_COUNT(skb_frag_size( &skb_shinfo(skb)->frags[f]));
- if (igc_maybe_stop_tx(tx_ring, count + 3)) { + if (igc_maybe_stop_tx(tx_ring, count + 5)) { /* this is a hard error */ return NETDEV_TX_BUSY; }
+ if (!tx_ring->launchtime_enable) + goto done; + + txtime = skb->tstamp; + skb->tstamp = ktime_set(0, 0); + launch_time = igc_tx_launchtime(tx_ring, txtime, &first_flag, &insert_empty); + + if (insert_empty) { + struct igc_tx_buffer *empty_info; + struct sk_buff *empty; + void *data; + + empty_info = &tx_ring->tx_buffer_info[tx_ring->next_to_use]; + empty = alloc_skb(IGC_EMPTY_FRAME_SIZE, GFP_ATOMIC); + if (!empty) + goto done; + + data = skb_put(empty, IGC_EMPTY_FRAME_SIZE); + memset(data, 0, IGC_EMPTY_FRAME_SIZE); + + igc_tx_ctxtdesc(tx_ring, 0, false, 0, 0, 0); + + if (igc_init_tx_empty_descriptor(tx_ring, + empty, + empty_info) < 0) + dev_kfree_skb_any(empty); + } + +done: /* record the location of the first descriptor for this packet */ first = &tx_ring->tx_buffer_info[tx_ring->next_to_use]; first->skb = skb; @@ -1366,11 +1484,11 @@ static netdev_tx_t igc_xmit_frame_ring(struct sk_buff *skb, first->tx_flags = tx_flags; first->protocol = protocol;
- tso = igc_tso(tx_ring, first, &hdr_len); + tso = igc_tso(tx_ring, first, launch_time, first_flag, &hdr_len); if (tso < 0) goto out_drop; else if (!tso) - igc_tx_csum(tx_ring, first); + igc_tx_csum(tx_ring, first, launch_time, first_flag);
igc_tx_map(tx_ring, first, hdr_len);