misc: mic: SCIF node queue pair setup management

SCIF node queue pair setup creates the SCIF driver kernel
mode private node queue pairs between all the nodes to enable
internal control message communication once SCIF gets probed
by the SCIF hardware bus. Peer to peer communication between
MIC Coprocessor nodes is supported.

Reviewed-by: Nikhil Rao <[email protected]>
Reviewed-by: Ashutosh Dixit <[email protected]>
Signed-off-by: Sudeep Dutt <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

Author: sudeepdutt

drivers/misc/mic/scif/scif_nm.c

@@ -0,0 +1,184 @@
+/*
+ * Intel MIC Platform Software Stack (MPSS)
+ *
+ * Copyright(c) 2014 Intel Corporation.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License, version 2, as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that 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.
+ *
+ * Intel SCIF driver.
+ *
+ */
+#include "scif_peer_bus.h"
+
+#include "scif_main.h"
+#include "scif_map.h"
+
+void scif_free_qp(struct scif_dev *scifdev)
+{
+	struct scif_qp *qp = scifdev->qpairs;
+
+	if (!qp)
+		return;
+	scif_free_coherent((void *)qp->inbound_q.rb_base,
+			   qp->local_buf, scifdev, qp->inbound_q.size);
+	scif_unmap_single(qp->local_qp, scifdev, sizeof(struct scif_qp));
+	kfree(scifdev->qpairs);
+	scifdev->qpairs = NULL;
+}
+
+static void scif_cleanup_qp(struct scif_dev *dev)
+{
+	struct scif_qp *qp = &dev->qpairs[0];
+
+	if (!qp)
+		return;
+	scif_iounmap((void *)qp->remote_qp, sizeof(struct scif_qp), dev);
+	scif_iounmap((void *)qp->outbound_q.rb_base,
+		     sizeof(struct scif_qp), dev);
+	qp->remote_qp = NULL;
+	qp->local_write = 0;
+	qp->inbound_q.current_write_offset = 0;
+	qp->inbound_q.current_read_offset = 0;
+	if (scifdev_is_p2p(dev))
+		scif_free_qp(dev);
+}
+
+void scif_send_acks(struct scif_dev *dev)
+{
+	struct scifmsg msg;
+
+	if (dev->node_remove_ack_pending) {
+		msg.uop = SCIF_NODE_REMOVE_ACK;
+		msg.src.node = scif_info.nodeid;
+		msg.dst.node = SCIF_MGMT_NODE;
+		msg.payload[0] = dev->node;
+		scif_nodeqp_send(&scif_dev[SCIF_MGMT_NODE], &msg);
+		dev->node_remove_ack_pending = false;
+	}
+	if (dev->exit_ack_pending) {
+		msg.uop = SCIF_EXIT_ACK;
+		msg.src.node = scif_info.nodeid;
+		msg.dst.node = dev->node;
+		scif_nodeqp_send(dev, &msg);
+		dev->exit_ack_pending = false;
+	}
+}
+
+/*
+ * scif_cleanup_scifdev
+ *
+ * @dev: Remote SCIF device.
+ * Uninitialize SCIF data structures for remote SCIF device.
+ */
+void scif_cleanup_scifdev(struct scif_dev *dev)
+{
+	struct scif_hw_dev *sdev = dev->sdev;
+
+	if (!dev->sdev)
+		return;
+	if (scifdev_is_p2p(dev)) {
+		if (dev->cookie) {
+			sdev->hw_ops->free_irq(sdev, dev->cookie, dev);
+			dev->cookie = NULL;
+		}
+		scif_destroy_intr_wq(dev);
+	}
+	scif_destroy_p2p(dev);
+	scif_send_acks(dev);
+	if (!dev->node && scif_info.card_initiated_exit) {
+		/*
+		 * Send an SCIF_EXIT message which is the last message from MIC
+		 * to the Host and wait for a SCIF_EXIT_ACK
+		 */
+		scif_send_exit(dev);
+		scif_info.card_initiated_exit = false;
+	}
+	scif_cleanup_qp(dev);
+}
+
+/*
+ * scif_remove_node:
+ *
+ * @node: Node to remove
+ */
+void scif_handle_remove_node(int node)
+{
+	struct scif_dev *scifdev = &scif_dev[node];
+	struct scif_peer_dev *spdev;
+
+	rcu_read_lock();
+	spdev = rcu_dereference(scifdev->spdev);
+	rcu_read_unlock();
+	if (spdev)
+		scif_peer_unregister_device(spdev);
+	else
+		scif_send_acks(scifdev);
+}
+
+static int scif_send_rmnode_msg(int node, int remove_node)
+{
+	struct scifmsg notif_msg;
+	struct scif_dev *dev = &scif_dev[node];
+
+	notif_msg.uop = SCIF_NODE_REMOVE;
+	notif_msg.src.node = scif_info.nodeid;
+	notif_msg.dst.node = node;
+	notif_msg.payload[0] = remove_node;
+	return scif_nodeqp_send(dev, &notif_msg);
+}
+
+/**
+ * scif_node_disconnect:
+ *
+ * @node_id[in]: source node id.
+ * @mgmt_initiated: Disconnection initiated from the mgmt node
+ *
+ * Disconnect a node from the scif network.
+ */
+void scif_disconnect_node(u32 node_id, bool mgmt_initiated)
+{
+	int ret;
+	int msg_cnt = 0;
+	u32 i = 0;
+	struct scif_dev *scifdev = &scif_dev[node_id];
+
+	if (!node_id)
+		return;
+
+	atomic_set(&scifdev->disconn_rescnt, 0);
+
+	/* Destroy p2p network */
+	for (i = 1; i <= scif_info.maxid; i++) {
+		if (i == node_id)
+			continue;
+		ret = scif_send_rmnode_msg(i, node_id);
+		if (!ret)
+			msg_cnt++;
+	}
+	/* Wait for the remote nodes to respond with SCIF_NODE_REMOVE_ACK */
+	ret = wait_event_timeout(scifdev->disconn_wq,
+				 (atomic_read(&scifdev->disconn_rescnt)
+				 == msg_cnt), SCIF_NODE_ALIVE_TIMEOUT);
+	/* Tell the card to clean up */
+	if (mgmt_initiated && _scifdev_alive(scifdev))
+		/*
+		 * Send an SCIF_EXIT message which is the last message from Host
+		 * to the MIC and wait for a SCIF_EXIT_ACK
+		 */
+		scif_send_exit(scifdev);
+	atomic_set(&scifdev->disconn_rescnt, 0);
+	/* Tell the mgmt node to clean up */
+	ret = scif_send_rmnode_msg(SCIF_MGMT_NODE, node_id);
+	if (!ret)
+		/* Wait for mgmt node to respond with SCIF_NODE_REMOVE_ACK */
+		wait_event_timeout(scifdev->disconn_wq,
+				   (atomic_read(&scifdev->disconn_rescnt) == 1),
+				   SCIF_NODE_ALIVE_TIMEOUT);
+}