The i226 hardware doesn't implement the process of verification
internally, this is left to the driver.

Add a simple implementation of the state machine defined in IEEE
802.3-2018, Section 99.4.7. The state machine is started manually by
user after "verify-enabled" command is enabled.

Implementation includes:
1. Send and receive verify frame
2. Verification state handling
3. Send and receive response frame

Tested by triggering verification handshake:
$ sudo ethtool --set-mm enp1s0 pmac-enabled on
$ sudo ethtool --set-mm enp1s0 tx-enabled on
$ sudo ethtool --set-mm enp1s0 verify-enabled on

Note that Ethtool API requires enabling "pmac-enabled on" and
"tx-enabled on" before "verify-enabled on" can be issued.

After the upcoming patch ("igc: Add support to get MAC Merge data via
ethtool") is implemented, verification status can be checked using:
$ ethtool --show-mm enp1s0
  MAC Merge layer state for enp1s0:
  pMAC enabled: on
  TX enabled: on
  TX active: on
  TX minimum fragment size: 252
  RX minimum fragment size: 252
  Verify enabled: on
  Verify time: 128
  Max verify time: 128
  Verification status: SUCCEEDED

Co-developed-by: Vinicius Costa Gomes <[email protected]>
Signed-off-by: Vinicius Costa Gomes <[email protected]>
Signed-off-by: Faizal Rahim <[email protected]>
---
 drivers/net/ethernet/intel/igc/igc.h         |  16 ++
 drivers/net/ethernet/intel/igc/igc_defines.h |   6 +
 drivers/net/ethernet/intel/igc/igc_ethtool.c |   8 +-
 drivers/net/ethernet/intel/igc/igc_main.c    |  15 +-
 drivers/net/ethernet/intel/igc/igc_tsn.c     | 230 +++++++++++++++++++
 drivers/net/ethernet/intel/igc/igc_tsn.h     |   4 +
 6 files changed, 277 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/intel/igc/igc.h 
b/drivers/net/ethernet/intel/igc/igc.h
index 5a14e9101723..56a426765be7 100644
--- a/drivers/net/ethernet/intel/igc/igc.h
+++ b/drivers/net/ethernet/intel/igc/igc.h
@@ -40,6 +40,15 @@ void igc_ethtool_set_ops(struct net_device *);
 
 #define IGC_MAX_TX_TSTAMP_REGS         4
 
+/* Verification state defined as per section 30.14.1.2 in 802.3br spec */
+enum verify_state {
+       VERIFY_FAIL,
+       INIT_VERIFICATION,
+       VERIFIED,
+       SEND_VERIFY,
+       WAIT_FOR_RESPONSE,
+};
+
 /**
  * @verify_time: see struct ethtool_mm_state
  * @verify_enabled: see struct ethtool_mm_state
@@ -52,6 +61,12 @@ void igc_ethtool_set_ops(struct net_device *);
  * @tx_min_frag_size: see struct ethtool_mm_state
  */
 struct fpe_t {
+       struct delayed_work verification_work;
+       unsigned long verify_timeout;
+       bool received_smd_v;
+       bool received_smd_r;
+       unsigned int verify_cnt;
+       enum verify_state verify_state;
        u32 verify_time;
        bool verify_enabled;
        bool tx_enabled;
@@ -758,6 +773,7 @@ int igc_add_nfc_rule(struct igc_adapter *adapter, struct 
igc_nfc_rule *rule);
 void igc_del_nfc_rule(struct igc_adapter *adapter, struct igc_nfc_rule *rule);
 int igc_enable_empty_addr_recv(struct igc_adapter *adapter);
 struct igc_ring *igc_get_tx_ring(struct igc_adapter *adapter, int cpu);
+void igc_flush_tx_descriptors(struct igc_ring *ring);
 void igc_ptp_init(struct igc_adapter *adapter);
 void igc_ptp_reset(struct igc_adapter *adapter);
 void igc_ptp_suspend(struct igc_adapter *adapter);
diff --git a/drivers/net/ethernet/intel/igc/igc_defines.h 
b/drivers/net/ethernet/intel/igc/igc_defines.h
index 3088cdd08f35..ba96776d5854 100644
--- a/drivers/net/ethernet/intel/igc/igc_defines.h
+++ b/drivers/net/ethernet/intel/igc/igc_defines.h
@@ -308,6 +308,8 @@
 #define IGC_TXD_DTYP_C         0x00000000 /* Context Descriptor */
 #define IGC_TXD_POPTS_IXSM     0x01       /* Insert IP checksum */
 #define IGC_TXD_POPTS_TXSM     0x02       /* Insert TCP/UDP checksum */
+#define IGC_TXD_POPTS_SMD_V    0x10       /* Transmitted packet is a 
SMD-Verify */
+#define IGC_TXD_POPTS_SMD_R    0x20       /* Transmitted packet is a 
SMD-Response */
 #define IGC_TXD_CMD_EOP                0x01000000 /* End of Packet */
 #define IGC_TXD_CMD_IC         0x04000000 /* Insert Checksum */
 #define IGC_TXD_CMD_DEXT       0x20000000 /* Desc extension (0 = legacy) */
@@ -370,9 +372,13 @@
 #define IGC_RXD_STAT_VP                0x08    /* IEEE VLAN Packet */
 
 #define IGC_RXDEXT_STATERR_LB  0x00040000
+#define IGC_RXD_STAT_SMD_V     0x2000  /* SMD-Verify packet */
+#define IGC_RXD_STAT_SMD_R     0x4000  /* SMD-Response packet */
 
 /* Advanced Receive Descriptor bit definitions */
 #define IGC_RXDADV_STAT_TSIP   0x08000 /* timestamp in packet */
+#define IGC_RXDADV_STAT_SMD_TYPE_MASK  0x06000
+#define IGC_RXDADV_STAT_SMD_TYPE_SHIFT 13
 
 #define IGC_RXDEXT_STATERR_L4E         0x20000000
 #define IGC_RXDEXT_STATERR_IPE         0x40000000
diff --git a/drivers/net/ethernet/intel/igc/igc_ethtool.c 
b/drivers/net/ethernet/intel/igc/igc_ethtool.c
index 1954561ec4aa..7cde0e5a7320 100644
--- a/drivers/net/ethernet/intel/igc/igc_ethtool.c
+++ b/drivers/net/ethernet/intel/igc/igc_ethtool.c
@@ -1788,6 +1788,7 @@ static int igc_ethtool_set_mm(struct net_device *netdev,
 {
        struct igc_adapter *adapter = netdev_priv(netdev);
        struct fpe_t *fpe = &adapter->fpe;
+       bool verify_enabled_changed;
 
        if (cmd->tx_min_frag_size < IGC_TX_MIN_FRAG_SIZE ||
            cmd->tx_min_frag_size > IGC_TX_MAX_FRAG_SIZE)
@@ -1805,7 +1806,12 @@ static int igc_ethtool_set_mm(struct net_device *netdev,
 
        fpe->tx_enabled = cmd->tx_enabled;
        fpe->pmac_enabled = cmd->pmac_enabled;
-       fpe->verify_enabled = cmd->verify_enabled;
+       verify_enabled_changed = (cmd->verify_enabled != fpe->verify_enabled);
+
+       if (verify_enabled_changed) {
+               fpe->verify_enabled = cmd->verify_enabled;
+               igc_fpe_verify_enabled_changed(fpe);
+       }
 
        return igc_tsn_offload_apply(adapter);
 }
diff --git a/drivers/net/ethernet/intel/igc/igc_main.c 
b/drivers/net/ethernet/intel/igc/igc_main.c
index b85eaf34d07b..e184959ef218 100644
--- a/drivers/net/ethernet/intel/igc/igc_main.c
+++ b/drivers/net/ethernet/intel/igc/igc_main.c
@@ -2534,7 +2534,7 @@ static struct sk_buff *igc_xdp_run_prog(struct 
igc_adapter *adapter,
 }
 
 /* This function assumes __netif_tx_lock is held by the caller. */
-static void igc_flush_tx_descriptors(struct igc_ring *ring)
+void igc_flush_tx_descriptors(struct igc_ring *ring)
 {
        /* Once tail pointer is updated, hardware can fetch the descriptors
         * any time so we issue a write membar here to ensure all memory
@@ -2585,6 +2585,7 @@ static int igc_clean_rx_irq(struct igc_q_vector 
*q_vector, const int budget)
        struct sk_buff *skb = rx_ring->skb;
        u16 cleaned_count = igc_desc_unused(rx_ring);
        int xdp_status = 0, rx_buffer_pgcnt;
+       int smd_type;
 
        while (likely(total_packets < budget)) {
                struct igc_xdp_buff ctx = { .rx_ts = NULL };
@@ -2622,6 +2623,18 @@ static int igc_clean_rx_irq(struct igc_q_vector 
*q_vector, const int budget)
                        size -= IGC_TS_HDR_LEN;
                }
 
+               smd_type = igc_fpe_get_smd_type(rx_desc->wb.upper.status_error);
+
+               if (igc_fpe_is_verify_or_response(smd_type, size)) {
+                       igc_fpe_preprocess_verify_response(&adapter->fpe,
+                                                          smd_type);
+
+                       /* Advance the ring next-to-clean */
+                       igc_is_non_eop(rx_ring, rx_desc);
+                       cleaned_count++;
+                       continue;
+               }
+
                if (!skb) {
                        xdp_init_buff(&ctx.xdp, truesize, &rx_ring->xdp_rxq);
                        xdp_prepare_buff(&ctx.xdp, pktbuf - 
igc_rx_offset(rx_ring),
diff --git a/drivers/net/ethernet/intel/igc/igc_tsn.c 
b/drivers/net/ethernet/intel/igc/igc_tsn.c
index b968c02f5fee..3d39be2219f3 100644
--- a/drivers/net/ethernet/intel/igc/igc_tsn.c
+++ b/drivers/net/ethernet/intel/igc/igc_tsn.c
@@ -1,22 +1,252 @@
 // SPDX-License-Identifier: GPL-2.0
 /* Copyright (c)  2019 Intel Corporation */
 
+#include <linux/kernel.h>
 #include "igc.h"
+#include "igc_base.h"
 #include "igc_hw.h"
 #include "igc_tsn.h"
 
 #define DEFAULT_VERIFY_TIME            10
+
+#define IGC_SMD_TYPE_SMD_V             0x1
+#define IGC_SMD_TYPE_SMD_R             0x2
 #define IGC_MIN_FOR_TX_MIN_FRAG                0
 #define IGC_MAX_FOR_TX_MIN_FRAG                3
 
+#define MAX_VERIFY_CNT                 3
+#define SMD_FRAME_SIZE                 60
+#define VERIFY_RESPONSE_DELAY          10
+
+static int igc_fpe_init_smd_frame(struct igc_ring *ring,
+                                 struct igc_tx_buffer *buffer,
+                                 struct sk_buff *skb)
+{
+       unsigned int size = skb_headlen(skb);
+       dma_addr_t dma;
+
+       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_fpe_init_tx_descriptor(struct igc_ring *ring,
+                                     struct sk_buff *skb, int type)
+{
+       struct igc_tx_buffer *buffer;
+       union igc_adv_tx_desc *desc;
+       u32 cmd_type, olinfo_status;
+       int err;
+
+       if (!igc_desc_unused(ring))
+               return -EBUSY;
+
+       if (type != IGC_SMD_TYPE_SMD_V && type != IGC_SMD_TYPE_SMD_R)
+               return -EINVAL;
+
+       buffer = &ring->tx_buffer_info[ring->next_to_use];
+       err = igc_fpe_init_smd_frame(ring, buffer, skb);
+       if (err)
+               return err;
+
+       cmd_type = IGC_ADVTXD_DTYP_DATA | IGC_ADVTXD_DCMD_DEXT |
+                  IGC_ADVTXD_DCMD_IFCS | IGC_TXD_DCMD |
+                  buffer->bytecount;
+       olinfo_status = buffer->bytecount << IGC_ADVTXD_PAYLEN_SHIFT;
+
+       switch (type) {
+       case IGC_SMD_TYPE_SMD_V:
+               olinfo_status |= (IGC_TXD_POPTS_SMD_V << 8);
+               break;
+       case IGC_SMD_TYPE_SMD_R:
+               olinfo_status |= (IGC_TXD_POPTS_SMD_R << 8);
+               break;
+       }
+
+       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(buffer, dma));
+
+       netdev_tx_sent_queue(txring_txq(ring), skb->len);
+
+       buffer->next_to_watch = desc;
+       ring->next_to_use = (ring->next_to_use + 1) % ring->count;
+
+       return 0;
+}
+
+static int igc_fpe_xmit_smd_frame(struct igc_adapter *adapter, int type)
+{
+       int cpu = smp_processor_id();
+       struct netdev_queue *nq;
+       struct igc_ring *ring;
+       struct sk_buff *skb;
+       void *data;
+       int err;
+
+       if (!netif_running(adapter->netdev))
+               return -ENOTCONN;
+
+       ring = igc_get_tx_ring(adapter, cpu);
+       nq = txring_txq(ring);
+
+       skb = alloc_skb(SMD_FRAME_SIZE, GFP_KERNEL);
+       if (!skb)
+               return -ENOMEM;
+
+       data = skb_put(skb, SMD_FRAME_SIZE);
+       memset(data, 0, SMD_FRAME_SIZE);
+
+       __netif_tx_lock(nq, cpu);
+
+       err = igc_fpe_init_tx_descriptor(ring, skb, type);
+       igc_flush_tx_descriptors(ring);
+
+       __netif_tx_unlock(nq);
+
+       return err;
+}
+
+static void igc_fpe_send_response(struct igc_adapter *adapter)
+{
+       int err = igc_fpe_xmit_smd_frame(adapter, IGC_SMD_TYPE_SMD_R);
+
+       if (err)
+               netdev_err(adapter->netdev, "Error sending SMD-R frame\n");
+}
+
+static void igc_fpe_handle_verify(struct igc_adapter *adapter)
+{
+       struct fpe_t *fpe = &adapter->fpe;
+       unsigned long verify_time_jiffies;
+       int err;
+
+       switch (fpe->verify_state) {
+       case SEND_VERIFY:
+               fpe->received_smd_r = false;
+               err = igc_fpe_xmit_smd_frame(adapter, IGC_SMD_TYPE_SMD_V);
+
+               if (err)
+                       netdev_err(adapter->netdev, "Error sending SMD-V\n");
+
+               fpe->verify_state = WAIT_FOR_RESPONSE;
+               verify_time_jiffies = msecs_to_jiffies(fpe->verify_time);
+               fpe->verify_timeout = jiffies + verify_time_jiffies;
+
+               schedule_delayed_work(&fpe->verification_work,
+                                     verify_time_jiffies);
+               break;
+
+       case WAIT_FOR_RESPONSE:
+               if (fpe->received_smd_r) {
+                       fpe->verify_state = VERIFIED;
+                       fpe->received_smd_r = false;
+               } else if (time_is_before_jiffies(fpe->verify_timeout)) {
+                       fpe->verify_cnt++;
+                       netdev_warn(adapter->netdev,
+                                   "Timeout waiting for SMD-R frame\n");
+
+                       if (fpe->verify_cnt > MAX_VERIFY_CNT) {
+                               fpe->verify_state = VERIFY_FAIL;
+                               netdev_err(adapter->netdev,
+                                          "Exceeded attempts sending SMD-V\n");
+                       } else {
+                               fpe->verify_state = SEND_VERIFY;
+                               igc_fpe_handle_verify(adapter);
+                       }
+               }
+               break;
+
+       case VERIFY_FAIL:
+       case VERIFIED:
+       case INIT_VERIFICATION:
+               break;
+       }
+}
+
+static void igc_fpe_verification(struct work_struct *work)
+{
+       struct delayed_work *dwork = to_delayed_work(work);
+       struct igc_adapter *adapter;
+       struct fpe_t *fpe;
+
+       fpe = container_of(dwork, struct fpe_t, verification_work);
+       adapter = container_of(fpe, struct igc_adapter, fpe);
+
+       if (fpe->received_smd_v) {
+               igc_fpe_send_response(adapter);
+               fpe->received_smd_v = false;
+       }
+
+       if (fpe->verify_enabled)
+               igc_fpe_handle_verify(adapter);
+}
+
 void igc_fpe_init(struct fpe_t *fpe)
 {
+       INIT_DELAYED_WORK(&fpe->verification_work, igc_fpe_verification);
        fpe->verify_enabled = false;
+       fpe->verify_state = INIT_VERIFICATION;
        fpe->verify_time = DEFAULT_VERIFY_TIME;
+       fpe->received_smd_v = false;
+       fpe->received_smd_r = false;
+       fpe->verify_cnt = 0;
        fpe->pmac_enabled = false;
        fpe->tx_min_frag_size = IGC_TX_MIN_FRAG_SIZE;
 }
 
+void igc_fpe_verify_enabled_changed(struct fpe_t *fpe)
+{
+       if (fpe->verify_enabled && fpe->tx_enabled) {
+               fpe->verify_state = SEND_VERIFY;
+               schedule_delayed_work(&fpe->verification_work,
+                                     msecs_to_jiffies(VERIFY_RESPONSE_DELAY));
+       } else {
+               fpe->verify_state = INIT_VERIFICATION;
+               fpe->received_smd_v = false;
+               fpe->received_smd_r = false;
+               fpe->verify_cnt = 0;
+       }
+}
+
+int igc_fpe_get_smd_type(__le32 status_error)
+{
+       u32 status = le32_to_cpu(status_error);
+
+       return (status & IGC_RXDADV_STAT_SMD_TYPE_MASK)
+               >> IGC_RXDADV_STAT_SMD_TYPE_SHIFT;
+}
+
+bool igc_fpe_is_verify_or_response(int smd_type, unsigned int size)
+{
+       return ((smd_type == IGC_SMD_TYPE_SMD_V ||
+                smd_type == IGC_SMD_TYPE_SMD_R) && size == SMD_FRAME_SIZE);
+}
+
+void igc_fpe_preprocess_verify_response(struct fpe_t *fpe, int smd_type)
+{
+       if (smd_type == IGC_SMD_TYPE_SMD_V)
+               fpe->received_smd_v = true;
+       else if (smd_type == IGC_SMD_TYPE_SMD_R)
+               fpe->received_smd_r = true;
+
+       schedule_delayed_work(&fpe->verification_work, 0);
+}
+
 static bool is_any_launchtime(struct igc_adapter *adapter)
 {
        int i;
diff --git a/drivers/net/ethernet/intel/igc/igc_tsn.h 
b/drivers/net/ethernet/intel/igc/igc_tsn.h
index 08e7582f257e..f3d83fbbd1f4 100644
--- a/drivers/net/ethernet/intel/igc/igc_tsn.h
+++ b/drivers/net/ethernet/intel/igc/igc_tsn.h
@@ -12,7 +12,11 @@
 #define MIN_VERIFY_TIME                        1
 #define MAX_VERIFY_TIME                        128
 
+int igc_fpe_get_smd_type(__le32 status_error);
 void igc_fpe_init(struct fpe_t *fpe);
+bool igc_fpe_is_verify_or_response(int smd_type, unsigned int size);
+void igc_fpe_preprocess_verify_response(struct fpe_t *fpe, int smd_type);
+void igc_fpe_verify_enabled_changed(struct fpe_t *fpe);
 int igc_tsn_offload_apply(struct igc_adapter *adapter);
 int igc_tsn_reset(struct igc_adapter *adapter);
 void igc_tsn_adjust_txtime_offset(struct igc_adapter *adapter);
-- 
2.25.1

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