Re: [alsa-devel] [very-RFC 3/8] Adding TSN-driver to Intel I210 controller

clearing up netdev-typo -H

On Sun, Jun 12, 2016 at 12:22:16AM +0200, Henrik Austad wrote:

This adds support for loading the igb.ko module with tsn capabilities. This requires a 2-step approach. First enabling TSN in .config, then load the module with use_tsn=1.

Once enabled and loaded, the controller will be placed in "Qav-mode" which is when the credit-based shaper is available, 3 of the queues are removed from regular traffic, max payload is set to 1522 octets (no jumboframes allowed).

It dumps the registers of interest before and after, so this clutters kern.log a bit. In time this will be reduced / tied to the debug-param for the module.

Note: currently this driver is *not* stable, it is still a work in progress.

Cc: Jeff Kirsher jeffrey.t.kirsher@intel.com Cc: intel-wired-lan@lists.osuosl.org Cc: "David S. Miller" davem@davemloft.net Signed-off-by: Henrik Austad haustad@cisco.com

---

drivers/net/ethernet/intel/Kconfig | 18 ++ drivers/net/ethernet/intel/igb/Makefile | 2 +- drivers/net/ethernet/intel/igb/igb.h | 19 ++ drivers/net/ethernet/intel/igb/igb_main.c | 10 +- drivers/net/ethernet/intel/igb/igb_tsn.c | 396 ++++++++++++++++++++++++++++++ 5 files changed, 443 insertions(+), 2 deletions(-) create mode 100644 drivers/net/ethernet/intel/igb/igb_tsn.c

diff --git a/drivers/net/ethernet/intel/Kconfig b/drivers/net/ethernet/intel/Kconfig index 714bd10..8e620a9 100644 --- a/drivers/net/ethernet/intel/Kconfig +++ b/drivers/net/ethernet/intel/Kconfig @@ -99,6 +99,24 @@ config IGB To compile this driver as a module, choose M here. The module will be called igb.

+config IGB_TSN

•   tristate "TSN Support for Intel(R) 82575/82576 i210 Network Controller"
  

•   depends on IGB && TSN
  

• ---help---

•  This driver supports TSN (AVB) on Intel I210 network controllers.
  

•  When enabled, it will allow the module to be loaded with
  

•  "use_tsn" which will initialize the controller to A/V-mode
  

•  instead of legacy-mode. This will take 3 of the tx-queues and
  

•  place them in 802.1Q QoS mode and enable the credit-based
  

•  shaper for 2 of the queues.
  

•  If built with this option, but not loaded with use_tsn, the
  

•  only difference is a slightly larger module, no extra
  

•  code paths are called.
  

•  If unsure, say No
  

config IGB_HWMON bool "Intel(R) PCI-Express Gigabit adapters HWMON support" default y diff --git a/drivers/net/ethernet/intel/igb/Makefile b/drivers/net/ethernet/intel/igb/Makefile index 5bcb2de..1a9b776 100644 --- a/drivers/net/ethernet/intel/igb/Makefile +++ b/drivers/net/ethernet/intel/igb/Makefile @@ -33,4 +33,4 @@ obj-$(CONFIG_IGB) += igb.o

igb-objs := igb_main.o igb_ethtool.o e1000_82575.o \ e1000_mac.o e1000_nvm.o e1000_phy.o e1000_mbx.o \

•    e1000_i210.o igb_ptp.o igb_hwmon.o
  

•    e1000_i210.o igb_ptp.o igb_hwmon.o igb_tsn.o
  

diff --git a/drivers/net/ethernet/intel/igb/igb.h b/drivers/net/ethernet/intel/igb/igb.h index b9609af..708f705 100644 --- a/drivers/net/ethernet/intel/igb/igb.h +++ b/drivers/net/ethernet/intel/igb/igb.h @@ -356,6 +356,7 @@ struct hwmon_buff { #define IGB_RETA_SIZE 128

/* board specific private data structure */

struct igb_adapter { unsigned long active_vlans[BITS_TO_LONGS(VLAN_N_VID)];

@@ -472,6 +473,13 @@ struct igb_adapter { int copper_tries; struct e1000_info ei; u16 eee_advert;

+#if IS_ENABLED(CONFIG_IGB_TSN)

• /* Reserved BW for class A and B */
• u16 sra_idleslope_res;
• u16 srb_idleslope_res;
• u8 tsn_ready:1;

+#endif /* IGB_TSN */ };

#define IGB_FLAG_HAS_MSI BIT(0) @@ -552,6 +560,17 @@ void igb_ptp_rx_pktstamp(struct igb_q_vector *q_vector, unsigned char *va, struct sk_buff *skb); int igb_ptp_set_ts_config(struct net_device *netdev, struct ifreq *ifr); int igb_ptp_get_ts_config(struct net_device *netdev, struct ifreq *ifr); +/* This should be the only place where we add ifdeffery

• • to include tsn-stuff or not. Everything else is located in igb_tsn.c
• */

+#if IS_ENABLED(CONFIG_IGB_TSN) +void igb_tsn_init(struct igb_adapter *adapter); +int igb_tsn_capable(struct net_device *netdev); +int igb_tsn_link_configure(struct net_device *netdev, enum sr_class sr_class,

• 	   u16 framesize, u16 vid);
  

+#else +static inline void igb_tsn_init(struct igb_adapter *adapter) { } +#endif /* CONFIG_IGB_TSN */ void igb_set_flag_queue_pairs(struct igb_adapter *, const u32); #ifdef CONFIG_IGB_HWMON void igb_sysfs_exit(struct igb_adapter *adapter); diff --git a/drivers/net/ethernet/intel/igb/igb_main.c b/drivers/net/ethernet/intel/igb/igb_main.c index ef3d642..4d8789f 100644 --- a/drivers/net/ethernet/intel/igb/igb_main.c +++ b/drivers/net/ethernet/intel/igb/igb_main.c @@ -2142,6 +2142,10 @@ static const struct net_device_ops igb_netdev_ops = { #ifdef CONFIG_NET_POLL_CONTROLLER .ndo_poll_controller = igb_netpoll, #endif +#if IS_ENABLED(CONFIG_IGB_TSN)

• .ndo_tsn_capable = igb_tsn_capable,
• .ndo_tsn_link_configure = igb_tsn_link_configure,

+#endif /* CONFIG_IGB_TSN */ .ndo_fix_features = igb_fix_features, .ndo_set_features = igb_set_features, .ndo_fdb_add = igb_ndo_fdb_add, @@ -2665,6 +2669,8 @@ static int igb_probe(struct pci_dev *pdev, const struct pci_device_id *ent) /* do hw tstamp init after resetting */ igb_ptp_init(adapter);

• igb_tsn_init(adapter);
• dev_info(&pdev->dev, "Intel(R) Gigabit Ethernet Network Connection\n"); /* print bus type/speed/width info, not applicable to i354 */ if (hw->mac.type != e1000_i354) {

@@ -5323,8 +5329,10 @@ static netdev_tx_t igb_xmit_frame(struct sk_buff *skb, /* The minimum packet size with TCTL.PSP set is 17 so pad the skb * in order to meet this minimum size requirement. */

• if (skb_put_padto(skb, 17))

• if (skb_put_padto(skb, 17)) {

• pr_err("%s: skb_put_padto FAILED. skb->len < 17\n", __func__);
  

  return NETDEV_TX_OK;

• }

  return igb_xmit_frame_ring(skb, igb_tx_queue_mapping(adapter, skb));

} diff --git a/drivers/net/ethernet/intel/igb/igb_tsn.c b/drivers/net/ethernet/intel/igb/igb_tsn.c new file mode 100644 index 0000000..641f4f2 --- /dev/null +++ b/drivers/net/ethernet/intel/igb/igb_tsn.c @@ -0,0 +1,396 @@ +/*

• • Copyright(c) 2015-2016 Henrik Austad haustad@cisco.com

• •                    Cisco Systems, Inc.
    

• • This program is free software; you can redistribute it and/or modify it
• • under the terms and conditions of the GNU General Public License,
• • version 2, as published by the Free Software Foundation.
• • This program is distributed in the hope it will be useful, but WITHOUT
• • ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
• • FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
• • more details.
• */

+/* FIXME: This should probably be handled by some Makefile-magic */

+#if IS_ENABLED(CONFIG_IGB_TSN) +#include "igb.h" +#include <linux/module.h>

+/* NOTE: keep the defines not present in e1000_regs.h to avoid

• • cluttering too many files. Once we are pretty stable, these will move
• • into it's proper home. Until then, make merge a bit easier by
• • avoiding it
• */

+/* Qav regs */ +#define E1000_IRPBS 0x02404 /* Rx Packet Buffer Size - RW */ +#define E1000_ITPBS 0x03404 /* Tx buffer size assignment */ +#define E1000_TQAVCTRL 0x03570 /* Tx Qav Control */ +#define E1000_DTXMXPKTSZ 0x0355C /* DMA TX Maximum Packet Size */

+/* Qav defines. */ +#define E1000_TQAVCH_ZERO_CREDIT 0x80000000 +#define E1000_LINK_RATE 0x7735

+/* queue mode, 0=strict, 1=SR mode */ +#define E1000_TQAVCC_QUEUEMODE 0x80000000 +/* Transmit mode, 0=legacy, 1=QAV */ +#define E1000_TQAVCTRL_TXMODE 0x00000001 +/* report DMA time of tx packets */ +#define E1000_TQAVCTRL_1588_STAT_EN 0x00000004 +/* data fetch arbitration */ +#define E1000_TQAVCTRL_DATA_FETCH_ARB 0x00000010 +/* data tx arbitration */ +#define E1000_TQAVCTRL_DATA_TRAN_ARB 0x00000100 +/* data launch time valid */ +#define E1000_TQAVCTRL_DATA_TRAN_TIM 0x00000200 +/* stall SP to guarantee SR */ +#define E1000_TQAVCTRL_SP_WAIT_SR 0x00000400

+/* ... and associated shift value */ +#define E1000_TQAVCTRL_FETCH_TM_SHIFT (16)

+/* QAV Tx mode control registers where _n can be 0 or 1. */ +#define E1000_TQAVCC(_idx) (0x03004 + 0x40 * (_idx))

+/* Tx Qav High Credit - See 7.2.7.6 for calculations

• • intel 8.12.18
• */

+#define E1000_TQAVHC(_idx) (0x0300C + 0x40 * (_idx))

+/* Queues priority masks where _n and _p can be 0-3. */

+#define MAX_FRAME_SIZE 1522 +#define MIN_FRAME_SIZE 64

+static int use_tsn = -1; +static int debug_tsn = -1; +module_param(use_tsn, int, 0); +module_param(debug_tsn, int, 0); +MODULE_PARM_DESC(use_tsn, "use_tsn (0=off, 1=enabled)"); +MODULE_PARM_DESC(debug_tsn, "debug_tsn (0=off, 1=enabled)");

+/* For a full list of the registers dumped here, see sec 8.1.3 in the

• • i210 controller datasheet.
• */

+static inline void _tsn_dump_regs(struct igb_adapter *adapter) +{

• u32 val = 0;
• struct device *dev;
• struct e1000_hw *hw = &adapter->hw;
• /* do not dump regs if we're not debugging driver */
• if (debug_tsn != 1)

• return;
  

• dev = &adapter->pdev->dev;
• dev_info(dev, "num_tx_queues=%d, num_rx_queues=%d\n",

•  adapter->num_tx_queues, adapter->num_rx_queues);
  

• /* 0x0008 - E1000_STATUS Device status register */
• val = rd32(E1000_STATUS);
• dev_info(&adapter->pdev->dev, "\n");
• dev_info(dev, "Status: FullDuplex=%s, LinkUp=%s, speed=%0x01x\n",

•  val & 0x1 ? "FD" : "HD",
  

•  val & 0x2 ? "LU" : "LD",
  

•  val & 0xc0 >> 6);
  

• /* E1000_VET vlan ether type */
• val = rd32(E1000_VET);
• dev_info(dev, "VLAN ether type: VET.VET=0x%04x, VET.VET_EXT=0x%04x\n",

•  val & 0xffff, (val >> 16) & 0xffff);
  

• /* E1000_RXPBS (RXPBSIZE) Rx Packet Buffer Size */
• val = rd32(E1000_RXPBS);
• dev_info(dev, "Rx Packet buffer: RXPBSIZE=%dkB, Bmc2ospbsize=%dkB, cfg_ts_en=%s\n",

•  val & 0x1f,
  

•  (val >> 6) & 0x1f,
  

•  (val & (1 << 31)) ? "cfg_ts_en" : "cfg_ts_dis");
  

• /* Transmit stuff */
• /* E1000_TXPBS (TXPBSIZE) Tx Packet Buffer Size - RW */
• val = rd32(E1000_TXPBS);
• dev_info(dev, "Tx Packet buffer: Txpb0size=%dkB, Txpb1size=%dkB, Txpb2size=%dkB, Txpb3size=%dkB, os2Bmcpbsize=%dkB\n",

•  val & 0x3f, (val >> 6) & 0x3f, (val >> 12) & 0x3f,
  

•  (val >> 18) & 0x3f, (val >> 24) & 0x3f);
  

• /* E1000_TCTL (TCTL) Tx control - RW*/
• val = rd32(E1000_TCTL);
• dev_info(dev, "Tx control reg: TxEnable=%s, CT=0x%X\n",

•  val & 2 ? "EN" : "DIS", (val >> 3) & 0x3F);
  

• /* TQAVHC : Transmit Qav High credits 0x300C + 0x40*n - RW */
• val = rd32(E1000_TQAVHC(0));
• dev_info(dev, "E1000_TQAVHC0: %0x08x\n", val);
• val = rd32(E1000_TQAVHC(1));
• dev_info(dev, "E1000_TQAVHC1: %0x08x\n", val);
• /* TQAVCC[0-1]: Transmit Qav 0x3004 + 0x40*n - RW */
• val = rd32(E1000_TQAVCC(0));
• dev_info(dev, "E1000_TQAVCC0: idleSlope=%02x, QueueMode=%s\n",

•  val % 0xff,
  

•  val > 31 ? "Stream reservation" : "Strict priority");
  

• val = rd32(E1000_TQAVCC(1));
• dev_info(dev, "E1000_TQAVCC1: idleSlope=%02x, QueueMode=%s\n",

•  val % 0xff,
  

•  val > 31 ? "Stream reservation" : "Strict priority");
  

• /* TQAVCTRL : Transmit Qav control - RW */
• val = rd32(E1000_TQAVCTRL);
• dev_info(dev, "E1000_TQAVCTRL: TransmitMode=%s,1588_STAT_EN=%s,DataFetchARB=%s,DataTranARB=%s,DataTranTIM=%s,SP_WAIT_SR=%s,FetchTimDelta=%dns (0x%04x)\n",

•  (val & 0x0001) ? "Qav" : "Legacy",
  

•  (val & 0x0004) ? "En" : "Dis",
  

•  (val & 0x0010) ? "Most Empty" : "Round Robin",
  

•  (val & 0x0100) ? "Credit Shaper" : "Strict priority",
  

•  (val & 0x0200) ? "Valid" : "N/A",
  

•  (val & 0x0400) ? "Wait" : "nowait",
  

•  (val >> 16) * 32, (val >> 16));
  

+}

+/* Place the NIC in Qav-mode.

• • This will result in a _single_ queue for normal BE traffic, the rest
• • will be grabbed by the Qav-machinery and kept for strict priority
• • transmission.
• • I210 Datasheet Sec 7.2.7.7 gives a lot of information.
• */

+void igb_tsn_init(struct igb_adapter *adapter) +{

• struct e1000_hw *hw = &adapter->hw;
• u32 val;
• if (use_tsn != 1) {

• adapter->tsn_ready = 0;
  

• dev_info(&adapter->pdev->dev, "%s got use_tsn > 0 (%d)\n",
  

• 	 __func__, use_tsn);
  

• return;
  

• }
• if (debug_tsn < 0 || debug_tsn > 1)

• debug_tsn = 0;
  

• if (!adapter->pdev) {

• adapter->tsn_ready = 0;
  

• return;
  

• }
• switch (adapter->pdev->device) {
• case 0x1533: /* E1000_DEV_ID_I210_COPPER */
• case 0x1536: /* E1000_DEV_ID_I210_FIBER */
• case 0x1537: /* E1000_DEV_ID_I210_SERDES: */
• case 0x1538: /* E1000_DEV_ID_I210_SGMII: */
• case 0x157b: /* E1000_DEV_ID_I210_COPPER_FLASHLESS: */
• case 0x157c: /* E1000_DEV_ID_I210_SERDES_FLASHLESS: */

• break;
  

• default:

• /* not a known IGB-TSN capable device */
  

• adapter->tsn_ready = 0;
  

• return;
  

• }
• _tsn_dump_regs(adapter);
• /* Set Tx packet buffer size assignment, see 7.2.7.7 in i210

• * PB0: 8kB
  

• * PB1: 8kB
  

• * PB2: 4kB
  

• * PB3: 4kB
  

• * os2bmcsize: 2kB
  

• * sumTx: 26kB
  

• *
  

• * Rxpbsize: 0x20 (32kB)
  

• * bmc2ossize: 0x02
  

• * sumRx: 34kB
  

• *
  

• * See 8.3.1 && 8.3.2
  

• */
  

• val = (0x02 << 24 | 0x04 << 18 | 0x04 << 12 | 0x08 << 6 | 0x08);
• wr32(E1000_ITPBS, val);
• wr32(E1000_IRPBS, (0x02 << 6 | 0x20));
• /* DMA Tx maximum packet size, the largest frame DMA should transport

• * do not allow frames larger than 1522 + preample. Reg expects
  

• * size in 64B increments. 802.1BA 6.3
  

• * Round up to 1536 to handle 64B increments
  

• *
  

• * Initial value: 0x98 (152 => 9728 bytes)
  

• */
  

• wr32(E1000_DTXMXPKTSZ, 1536 >> 6);
• /* Place card in Qav-mode, use tx-queue 0,1 for Qav

• * (Credit-based shaper), 2,3 for standard priority (and
  

• * best-effort) traffic.
  

• *
  

• * i210 8.12.19 and 8.12.21
  

• *
  

• * - Fetch: most empty and time based (not round-robin)
  

• * - Transmit: Credit based shaper for SR queues
  

• * - Data launch time valid (in Qav mode)
  

• * - Wait for SR queues to ensure that launch time is always valid.
  

• * - Set ~10us wait-time-delta, 32ns granularity
  

• *
  

• * Do *not* enable Tx for shaper (E1000_TQAVCTRL_DATA_TRAN_ARB)
  

• * yet as we do not have data to Tx
  

• */
  

• val = E1000_TQAVCTRL_TXMODE |

• E1000_TQAVCTRL_DATA_FETCH_ARB |
  

• E1000_TQAVCTRL_DATA_TRAN_TIM  |
  

• E1000_TQAVCTRL_SP_WAIT_SR     |
  

• 320 << E1000_TQAVCTRL_FETCH_TM_SHIFT;
  

• wr32(E1000_TQAVCTRL, val);
• /* For now, only set CreditBased shaper for A and B, not set

• * idleSlope as we have not yet gotten any streams.
  

• * 8.12.19
  

• */
  

• wr32(E1000_TQAVCC(0), E1000_TQAVCC_QUEUEMODE);
• wr32(E1000_TQAVCC(1), E1000_TQAVCC_QUEUEMODE);
• wr32(E1000_TQAVHC(0), E1000_TQAVCH_ZERO_CREDIT);
• wr32(E1000_TQAVHC(1), E1000_TQAVCH_ZERO_CREDIT);
• /* reset Tx Descriptor tail and head for the queues */
• wr32(E1000_TDT(0), 0);
• wr32(E1000_TDT(1), 0);
• wr32(E1000_TDH(0), 0);
• wr32(E1000_TDH(1), 0);
• _tsn_dump_regs(adapter);
• dev_info(&adapter->pdev->dev, "\n");
• adapter->sra_idleslope_res = 0;
• adapter->srb_idleslope_res = 0;
• adapter->tsn_ready = 1;
• dev_info(&adapter->pdev->dev, "%s: setup done\n", __func__);

+}

+int igb_tsn_capable(struct net_device *netdev) +{

• struct igb_adapter *adapter;
• if (!netdev)

• return -EINVAL;
  

• adapter = netdev_priv(netdev);
• if (use_tsn == 1)

• return adapter->tsn_ready == 1;
  

• return 0;

+}

+/* igb_tsn_link_configure - configure NIC to handle a new stream

• • @netdev: pointer to NIC device
• • @class: the class for the stream used to find the correct queue.
• • @framesize: size of each frame, *including* headers (not preamble)
• • @vid: VLAN ID
• • NOTE: the sr_class only instructs the driver which queue to use, not
• • what priority the network expects for a given class. This is
• • something userspace must find out and then let the tsn-driver set in
• • the frame before xmit.
• • FIXME: remove bw-req from a stream that goes away.
• */

+int igb_tsn_link_configure(struct net_device *netdev, enum sr_class class,

• 	   u16 framesize, u16 vid)
  

+{

• /* FIXME: push into adapter-storage */
• static int class_a_size;
• static int class_b_size;
• int err;
• u32 idle_slope_a = 0;
• u32 idle_slope_b = 0;
• u32 new_is = 0;
• u32 hicred_a = 0;
• u32 hicred_b = 0;
• u32 tqavctrl;
• struct igb_adapter *adapter;
• struct e1000_hw *hw;
• if (!netdev)

• return -EINVAL;
  

• adapter = netdev_priv(netdev);
• hw = &adapter->hw;
• if (!igb_tsn_capable(netdev)) {

• pr_err("%s:  NIC not capable\n", __func__);
  

• return -EINVAL;
  

• }
• if (framesize > MAX_FRAME_SIZE || framesize < MIN_FRAME_SIZE) {

• pr_err("%s: framesize (%u) must be [%d,%d]\n", __func__,
  

•        framesize, MIN_FRAME_SIZE, MAX_FRAME_SIZE);
  

• return -EINVAL;
  

• }
• /* TODO: is this the correct place/way? Is it required? */
• rtnl_lock();
• pr_info("%s: adding VLAN %u to HW filter on device %s\n",

• __func__, vid, netdev->name);
  

• err = vlan_vid_add(netdev, htons(ETH_P_8021Q), vid);
• if (err != 0)

• pr_err("%s: error adding vlan %u, res=%d\n",
  

•        __func__, vid, err);
  

• rtnl_unlock();
• /* Grab current values of idle_slope */
• idle_slope_a = rd32(E1000_TQAVHC(0)) & ~E1000_TQAVCH_ZERO_CREDIT;
• idle_slope_b = rd32(E1000_TQAVHC(1)) & ~E1000_TQAVCH_ZERO_CREDIT;
• /* Calculate new idle slope and add to appropriate idle_slope

• * idle_slope = BW * linkrate * 2 (0r 0.2 for 100Mbit)
  

• * BW: % of total bandwidth
  

• */
  

• new_is = framesize * E1000_LINK_RATE * 16 / 1000000;
• switch (class) {
• case SR_CLASS_A:

• new_is *= 2; /* A is 8kHz, B is 4kHz */
  

• idle_slope_a += new_is;
  

• class_a_size  = framesize;
  

• break;
  

• case SR_CLASS_B:

• idle_slope_b += new_is;
  

• class_b_size  = framesize;
  

• break;
  

• default:

• pr_err("%s: unhandled SR-class (%d)\n", __func__, class);
  

• return -EINVAL;
  

• }
• /* HiCred: cred obtained while waiting for current frame &&

• * higher-class frames to finish xmit.
  

• *
  

• * Covered in detail in 7.2.7.6 in i210 datasheet
  

• * For class A: only worst-case framesize that just started;
  

• *		i.e. 1522 * idleSlope / linkrate;
  

• * For class B: (worst-case framesize + burstSize(A))*idleSlope
  

• *
  

• * See 802.1Q Annex L, eq L.10 for hicred_a and L.41 for
  

• * hicred_b
  

• */
  

• if (class == SR_CLASS_A) {

• hicred_a = E1000_TQAVCH_ZERO_CREDIT + idle_slope_a * MAX_FRAME_SIZE / E1000_LINK_RATE;
  

• wr32(E1000_TQAVCC(0), E1000_TQAVCC_QUEUEMODE | idle_slope_a);
  

• wr32(E1000_TQAVHC(0), hicred_a);
  

• } else {

• hicred_b = E1000_TQAVCH_ZERO_CREDIT | idle_slope_b * (MAX_FRAME_SIZE + class_a_size) / (E1000_LINK_RATE - idle_slope_a);
  

• wr32(E1000_TQAVCC(1), E1000_TQAVCC_QUEUEMODE | idle_slope_b);
  

• wr32(E1000_TQAVHC(1), hicred_b);
  

• }
• /* Enable Tx for shaper now that we have data */
• tqavctrl = rd32(E1000_TQAVCTRL);
• if (!(tqavctrl & E1000_TQAVCTRL_DATA_TRAN_ARB)) {

• tqavctrl |= E1000_TQAVCTRL_DATA_TRAN_ARB;
  

• wr32(E1000_TQAVCTRL, tqavctrl);
  

• }
• _tsn_dump_regs(netdev_priv(netdev));
• return 0;

+}

+#endif /* #if IS_ENABLED(CONFIG_IGB_TSN) */

2.7.4