Message-Id: <20210419172752.57089-1-cforno12@linux.ibm.com>
Date:   Mon, 19 Apr 2021 12:27:52 -0500
From:   Cristobal Forno <cforno12@...ux.ibm.com>
To:     netdev@...r.kernel.org
Cc:     Cristobal Forno <cforno12@...ux.ibm.com>,
        Thomas Falcon <tlfalcon@...ux.ibm.com>
Subject: [PATCH net] ibmvnic: Allow device probe if the device is not ready at boot

This patch will allow the device to be initialized at a later time if
it is not available at boot. The device will be allowed to probe but
will be given a "down" state. After completing device probe and
registering the net device, the driver will await an interrupt signal
from its partner device, indicating that it is ready for boot. The
driver will schedule a work event to perform the necessary procedure
and begin operation.

Signed-off-by: Cristobal Forno <cforno12@...ux.ibm.com>
Co-developed-by: Thomas Falcon <tlfalcon@...ux.ibm.com>
---
 drivers/net/ethernet/ibm/ibmvnic.c | 145 ++++++++++++++++++++++++-----
 drivers/net/ethernet/ibm/ibmvnic.h |   6 +-
 2 files changed, 128 insertions(+), 23 deletions(-)

diff --git a/drivers/net/ethernet/ibm/ibmvnic.c b/drivers/net/ethernet/ibm/ibmvnic.c
index ffb2a91750c7..64798e1f429d 100644
--- a/drivers/net/ethernet/ibm/ibmvnic.c
+++ b/drivers/net/ethernet/ibm/ibmvnic.c
@@ -141,6 +141,30 @@ static const struct ibmvnic_stat ibmvnic_stats[] = {
 	{"internal_mac_rx_errors", IBMVNIC_STAT_OFF(internal_mac_rx_errors)},
 };
 
+static int send_crq_init_complete(struct ibmvnic_adapter *adapter)
+{
+	union ibmvnic_crq crq;
+
+	memset(&crq, 0, sizeof(crq));
+	crq.generic.first = IBMVNIC_CRQ_INIT_CMD;
+	crq.generic.cmd = IBMVNIC_CRQ_INIT_COMPLETE;
+	netdev_dbg(adapter->netdev, "Sending CRQ init complete\n");
+
+	return ibmvnic_send_crq(adapter, &crq);
+}
+
+static int send_version_xchg(struct ibmvnic_adapter *adapter)
+{
+	union ibmvnic_crq crq;
+
+	memset(&crq, 0, sizeof(crq));
+	crq.version_exchange.first = IBMVNIC_CRQ_CMD;
+	crq.version_exchange.cmd = VERSION_EXCHANGE;
+	crq.version_exchange.version = cpu_to_be16(ibmvnic_version);
+
+	return ibmvnic_send_crq(adapter, &crq);
+}
+
 static long h_reg_sub_crq(unsigned long unit_address, unsigned long token,
 			  unsigned long length, unsigned long *number,
 			  unsigned long *irq)
@@ -2221,6 +2245,75 @@ static struct ibmvnic_rwi *get_next_rwi(struct ibmvnic_adapter *adapter)
 	return rwi;
 }
 
+/* ibmvnic_do_passive_init()
+ * Perform the initialization of the device at a later time
+ *
+ * If the ibmvnic was does not have a partner device to communicate with at boot
+ * and that partner device comes online at a later time, this function is called
+ * to complete the initalization process of ibmvnic.
+ * Caller should not hold rtnl_lock().
+ *
+ *
+ * Returns non-zero if sub-CRQs are not initialized properly leaving the device
+ * in the down state.
+ * Returns 0 upon success and the device is probed.
+ */
+
+static int do_passive_init(struct ibmvnic_adapter *adapter)
+{
+	unsigned long timeout = msecs_to_jiffies(30000);
+	struct net_device *netdev = adapter->netdev;
+	struct device *dev = &adapter->vdev->dev;
+	int rc;
+
+	netdev_dbg(adapter->netdev, "Partner device not found, probing.\n");
+
+	adapter->state = VNIC_PROBING;
+	reinit_completion(&adapter->init_done);
+	adapter->init_done_rc = 0;
+	adapter->crq.active = true;
+
+	rc = send_crq_init_complete(adapter);
+	if (rc)
+		goto out;
+
+	rc = send_version_xchg(adapter);
+	netdev_dbg(adapter->netdev, "send_version_xchg rc=%d", rc);
+
+	if (!wait_for_completion_timeout(&adapter->init_done, timeout)) {
+		dev_err(dev, "Initialization sequence timed out\n");
+		rc = -ETIMEDOUT;
+		goto out;
+	}
+
+	rc = init_sub_crqs(adapter);
+	if (rc) {
+		dev_err(dev, "Initialization of sub crqs failed, rc=%d\n", rc);
+		goto out;
+	}
+
+	rc = init_sub_crq_irqs(adapter);
+	if (rc) {
+		dev_err(dev, "Failed to initialize sub crq irqs\n, rc=%d", rc);
+		goto init_failed;
+	}
+
+	netdev->mtu = adapter->req_mtu - ETH_HLEN;
+	netdev->min_mtu = adapter->min_mtu - ETH_HLEN;
+	netdev->max_mtu = adapter->max_mtu - ETH_HLEN;
+
+	adapter->state = VNIC_PROBED;
+	netdev_dbg(adapter->netdev, "Probed successfully. Waiting for signal from partner device.\n");
+
+	return 0;
+
+init_failed:
+	release_sub_crqs(adapter, 1);
+out:
+	adapter->state = VNIC_DOWN;
+	return rc;
+}
+
 static void __ibmvnic_reset(struct work_struct *work)
 {
 	struct ibmvnic_rwi *rwi;
@@ -2256,7 +2349,13 @@ static void __ibmvnic_reset(struct work_struct *work)
 		}
 		spin_unlock_irqrestore(&adapter->state_lock, flags);
 
-		if (adapter->force_reset_recovery) {
+		if (rwi->reset_reason == VNIC_RESET_PASSIVE_INIT) {
+			rtnl_lock();
+			rc = do_passive_init(adapter);
+			rtnl_unlock();
+			if (!rc)
+				netif_carrier_on(adapter->netdev);
+		} else if (adapter->force_reset_recovery) {
 			/* Since we are doing a hard reset now, clear the
 			 * failover_pending flag so we don't ignore any
 			 * future MOBILITY or other resets.
@@ -3724,18 +3823,6 @@ static int ibmvnic_send_crq_init(struct ibmvnic_adapter *adapter)
 	return 0;
 }
 
-static int send_version_xchg(struct ibmvnic_adapter *adapter)
-{
-	union ibmvnic_crq crq;
-
-	memset(&crq, 0, sizeof(crq));
-	crq.version_exchange.first = IBMVNIC_CRQ_CMD;
-	crq.version_exchange.cmd = VERSION_EXCHANGE;
-	crq.version_exchange.version = cpu_to_be16(ibmvnic_version);
-
-	return ibmvnic_send_crq(adapter, &crq);
-}
-
 struct vnic_login_client_data {
 	u8	type;
 	__be16	len;
@@ -4855,7 +4942,12 @@ static void ibmvnic_handle_crq(union ibmvnic_crq *crq,
 				complete(&adapter->init_done);
 				adapter->init_done_rc = -EIO;
 			}
-			rc = ibmvnic_reset(adapter, VNIC_RESET_FAILOVER);
+
+			if (adapter->state == VNIC_DOWN)
+				rc = ibmvnic_reset(adapter, VNIC_RESET_PASSIVE_INIT);
+			else
+				rc = ibmvnic_reset(adapter, VNIC_RESET_FAILOVER);
+
 			if (rc && rc != -EBUSY) {
 				/* We were unable to schedule the failover
 				 * reset either because the adapter was still
@@ -5278,6 +5370,7 @@ static int ibmvnic_probe(struct vio_dev *dev, const struct vio_device_id *id)
 	struct ibmvnic_adapter *adapter;
 	struct net_device *netdev;
 	unsigned char *mac_addr_p;
+	bool init_success;
 	int rc;
 
 	dev_dbg(&dev->dev, "entering ibmvnic_probe for UA 0x%x\n",
@@ -5324,6 +5417,7 @@ static int ibmvnic_probe(struct vio_dev *dev, const struct vio_device_id *id)
 	init_completion(&adapter->stats_done);
 	clear_bit(0, &adapter->resetting);
 
+	init_success = false;
 	do {
 		rc = init_crq_queue(adapter);
 		if (rc) {
@@ -5333,10 +5427,16 @@ static int ibmvnic_probe(struct vio_dev *dev, const struct vio_device_id *id)
 		}
 
 		rc = ibmvnic_reset_init(adapter, false);
-		if (rc && rc != EAGAIN)
-			goto ibmvnic_init_fail;
 	} while (rc == EAGAIN);
 
+	/* We are ignoring the error from ibmvnic_reset_init() assuming that the
+	 * partner is not ready. When the partner becomes ready, we will do the
+	 * passive init reset.
+	 */
+
+	if (!rc)
+		init_success = true;
+
 	rc = init_stats_buffers(adapter);
 	if (rc)
 		goto ibmvnic_init_fail;
@@ -5345,10 +5445,6 @@ static int ibmvnic_probe(struct vio_dev *dev, const struct vio_device_id *id)
 	if (rc)
 		goto ibmvnic_stats_fail;
 
-	netdev->mtu = adapter->req_mtu - ETH_HLEN;
-	netdev->min_mtu = adapter->min_mtu - ETH_HLEN;
-	netdev->max_mtu = adapter->max_mtu - ETH_HLEN;
-
 	rc = device_create_file(&dev->dev, &dev_attr_failover);
 	if (rc)
 		goto ibmvnic_dev_file_err;
@@ -5361,7 +5457,14 @@ static int ibmvnic_probe(struct vio_dev *dev, const struct vio_device_id *id)
 	}
 	dev_info(&dev->dev, "ibmvnic registered\n");
 
-	adapter->state = VNIC_PROBED;
+	if (init_success) {
+		adapter->state = VNIC_PROBED;
+		netdev->mtu = adapter->req_mtu - ETH_HLEN;
+		netdev->min_mtu = adapter->min_mtu - ETH_HLEN;
+		netdev->max_mtu = adapter->max_mtu - ETH_HLEN;
+	} else {
+		adapter->state = VNIC_DOWN;
+	}
 
 	adapter->wait_for_reset = false;
 	adapter->last_reset_time = jiffies;
diff --git a/drivers/net/ethernet/ibm/ibmvnic.h b/drivers/net/ethernet/ibm/ibmvnic.h
index 806aa75a4e86..98a383e89e44 100644
--- a/drivers/net/ethernet/ibm/ibmvnic.h
+++ b/drivers/net/ethernet/ibm/ibmvnic.h
@@ -945,14 +945,16 @@ enum vnic_state {VNIC_PROBING = 1,
 		 VNIC_CLOSING,
 		 VNIC_CLOSED,
 		 VNIC_REMOVING,
-		 VNIC_REMOVED};
+		 VNIC_REMOVED,
+		 VNIC_DOWN};
 
 enum ibmvnic_reset_reason {VNIC_RESET_FAILOVER = 1,
 			   VNIC_RESET_MOBILITY,
 			   VNIC_RESET_FATAL,
 			   VNIC_RESET_NON_FATAL,
 			   VNIC_RESET_TIMEOUT,
-			   VNIC_RESET_CHANGE_PARAM};
+			   VNIC_RESET_CHANGE_PARAM,
+			   VNIC_RESET_PASSIVE_INIT};
 
 struct ibmvnic_rwi {
 	enum ibmvnic_reset_reason reset_reason;
-- 
2.30.0

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