Adding upstream version 4.19.249.upstream/4.19.249

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1354 insertions, 0 deletions

diff --git a/drivers/misc/mic/scif/scif_nodeqp.c b/drivers/misc/mic/scif/scif_nodeqp.c
new file mode 100644
index 000000000..c66ca1a58
--- /dev/null
+++ b/drivers/misc/mic/scif/scif_nodeqp.c
@@ -0,0 +1,1354 @@
+/*
+ * 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 "../bus/scif_bus.h"
+#include "scif_peer_bus.h"
+#include "scif_main.h"
+#include "scif_nodeqp.h"
+#include "scif_map.h"
+
+/*
+ ************************************************************************
+ * SCIF node Queue Pair (QP) setup flow:
+ *
+ * 1) SCIF driver gets probed with a scif_hw_dev via the scif_hw_bus
+ * 2) scif_setup_qp(..) allocates the local qp and calls
+ *	scif_setup_qp_connect(..) which allocates and maps the local
+ *	buffer for the inbound QP
+ * 3) The local node updates the device page with the DMA address of the QP
+ * 4) A delayed work is scheduled (qp_dwork) which periodically reads if
+ *	the peer node has updated its QP DMA address
+ * 5) Once a valid non zero address is found in the QP DMA address field
+ *	in the device page, the local node maps the remote node's QP,
+ *	updates its outbound QP and sends a SCIF_INIT message to the peer
+ * 6) The SCIF_INIT message is received by the peer node QP interrupt bottom
+ *	half handler by calling scif_init(..)
+ * 7) scif_init(..) registers a new SCIF peer node by calling
+ *	scif_peer_register_device(..) which signifies the addition of a new
+ *	SCIF node
+ * 8) On the mgmt node, P2P network setup/teardown is initiated if all the
+ *	remote nodes are online via scif_p2p_setup(..)
+ * 9) For P2P setup, the host maps the remote nodes' aperture and memory
+ *	bars and sends a SCIF_NODE_ADD message to both nodes
+ * 10) As part of scif_nodeadd, both nodes set up their local inbound
+ *	QPs and send a SCIF_NODE_ADD_ACK to the mgmt node
+ * 11) As part of scif_node_add_ack(..) the mgmt node forwards the
+ *	SCIF_NODE_ADD_ACK to the remote nodes
+ * 12) As part of scif_node_add_ack(..) the remote nodes update their
+ *	outbound QPs, make sure they can access memory on the remote node
+ *	and then add a new SCIF peer node by calling
+ *	scif_peer_register_device(..) which signifies the addition of a new
+ *	SCIF node.
+ * 13) The SCIF network is now established across all nodes.
+ *
+ ************************************************************************
+ * SCIF node QP teardown flow (initiated by non mgmt node):
+ *
+ * 1) SCIF driver gets a remove callback with a scif_hw_dev via the scif_hw_bus
+ * 2) The device page QP DMA address field is updated with 0x0
+ * 3) A non mgmt node now cleans up all local data structures and sends a
+ *	SCIF_EXIT message to the peer and waits for a SCIF_EXIT_ACK
+ * 4) As part of scif_exit(..) handling scif_disconnect_node(..) is called
+ * 5) scif_disconnect_node(..) sends a SCIF_NODE_REMOVE message to all the
+ *	peers and waits for a SCIF_NODE_REMOVE_ACK
+ * 6) As part of scif_node_remove(..) a remote node unregisters the peer
+ *	node from the SCIF network and sends a SCIF_NODE_REMOVE_ACK
+ * 7) When the mgmt node has received all the SCIF_NODE_REMOVE_ACKs
+ *	it sends itself a node remove message whose handling cleans up local
+ *	data structures and unregisters the peer node from the SCIF network
+ * 8) The mgmt node sends a SCIF_EXIT_ACK
+ * 9) Upon receipt of the SCIF_EXIT_ACK the node initiating the teardown
+ *	completes the SCIF remove routine
+ * 10) The SCIF network is now torn down for the node initiating the
+ *	teardown sequence
+ *
+ ************************************************************************
+ * SCIF node QP teardown flow (initiated by mgmt node):
+ *
+ * 1) SCIF driver gets a remove callback with a scif_hw_dev via the scif_hw_bus
+ * 2) The device page QP DMA address field is updated with 0x0
+ * 3) The mgmt node calls scif_disconnect_node(..)
+ * 4) scif_disconnect_node(..) sends a SCIF_NODE_REMOVE message to all the peers
+ *	and waits for a SCIF_NODE_REMOVE_ACK
+ * 5) As part of scif_node_remove(..) a remote node unregisters the peer
+ *	node from the SCIF network and sends a SCIF_NODE_REMOVE_ACK
+ * 6) When the mgmt node has received all the SCIF_NODE_REMOVE_ACKs
+ *	it unregisters the peer node from the SCIF network
+ * 7) The mgmt node sends a SCIF_EXIT message and waits for a SCIF_EXIT_ACK.
+ * 8) A non mgmt node upon receipt of a SCIF_EXIT message calls scif_stop(..)
+ *	which would clean up local data structures for all SCIF nodes and
+ *	then send a SCIF_EXIT_ACK back to the mgmt node
+ * 9) Upon receipt of the SCIF_EXIT_ACK the the mgmt node sends itself a node
+ *	remove message whose handling cleans up local data structures and
+ *	destroys any P2P mappings.
+ * 10) The SCIF hardware device for which a remove callback was received is now
+ *	disconnected from the SCIF network.
+ */
+/*
+ * Initializes "local" data structures for the QP. Allocates the QP
+ * ring buffer (rb) and initializes the "in bound" queue.
+ */
+int scif_setup_qp_connect(struct scif_qp *qp, dma_addr_t *qp_offset,
+			  int local_size, struct scif_dev *scifdev)
+{
+	void *local_q = qp->inbound_q.rb_base;
+	int err = 0;
+	u32 tmp_rd = 0;
+
+	spin_lock_init(&qp->send_lock);
+	spin_lock_init(&qp->recv_lock);
+
+	/* Allocate rb only if not already allocated */
+	if (!local_q) {
+		local_q = kzalloc(local_size, GFP_KERNEL);
+		if (!local_q) {
+			err = -ENOMEM;
+			return err;
+		}
+	}
+
+	err = scif_map_single(&qp->local_buf, local_q, scifdev, local_size);
+	if (err)
+		goto kfree;
+	/*
+	 * To setup the inbound_q, the buffer lives locally, the read pointer
+	 * is remote and the write pointer is local.
+	 */
+	scif_rb_init(&qp->inbound_q,
+		     &tmp_rd,
+		     &qp->local_write,
+		     local_q, get_count_order(local_size));
+	/*
+	 * The read pointer is NULL initially and it is unsafe to use the ring
+	 * buffer til this changes!
+	 */
+	qp->inbound_q.read_ptr = NULL;
+	err = scif_map_single(qp_offset, qp,
+			      scifdev, sizeof(struct scif_qp));
+	if (err)
+		goto unmap;
+	qp->local_qp = *qp_offset;
+	return err;
+unmap:
+	scif_unmap_single(qp->local_buf, scifdev, local_size);
+	qp->local_buf = 0;
+kfree:
+	kfree(local_q);
+	return err;
+}
+
+/* When the other side has already done it's allocation, this is called */
+int scif_setup_qp_accept(struct scif_qp *qp, dma_addr_t *qp_offset,
+			 dma_addr_t phys, int local_size,
+			 struct scif_dev *scifdev)
+{
+	void *local_q;
+	void *remote_q;
+	struct scif_qp *remote_qp;
+	int remote_size;
+	int err = 0;
+
+	spin_lock_init(&qp->send_lock);
+	spin_lock_init(&qp->recv_lock);
+	/* Start by figuring out where we need to point */
+	remote_qp = scif_ioremap(phys, sizeof(struct scif_qp), scifdev);
+	if (!remote_qp)
+		return -EIO;
+	qp->remote_qp = remote_qp;
+	if (qp->remote_qp->magic != SCIFEP_MAGIC) {
+		err = -EIO;
+		goto iounmap;
+	}
+	qp->remote_buf = remote_qp->local_buf;
+	remote_size = qp->remote_qp->inbound_q.size;
+	remote_q = scif_ioremap(qp->remote_buf, remote_size, scifdev);
+	if (!remote_q) {
+		err = -EIO;
+		goto iounmap;
+	}
+	qp->remote_qp->local_write = 0;
+	/*
+	 * To setup the outbound_q, the buffer lives in remote memory,
+	 * the read pointer is local, the write pointer is remote
+	 */
+	scif_rb_init(&qp->outbound_q,
+		     &qp->local_read,
+		     &qp->remote_qp->local_write,
+		     remote_q,
+		     get_count_order(remote_size));
+	local_q = kzalloc(local_size, GFP_KERNEL);
+	if (!local_q) {
+		err = -ENOMEM;
+		goto iounmap_1;
+	}
+	err = scif_map_single(&qp->local_buf, local_q, scifdev, local_size);
+	if (err)
+		goto kfree;
+	qp->remote_qp->local_read = 0;
+	/*
+	 * To setup the inbound_q, the buffer lives locally, the read pointer
+	 * is remote and the write pointer is local
+	 */
+	scif_rb_init(&qp->inbound_q,
+		     &qp->remote_qp->local_read,
+		     &qp->local_write,
+		     local_q, get_count_order(local_size));
+	err = scif_map_single(qp_offset, qp, scifdev,
+			      sizeof(struct scif_qp));
+	if (err)
+		goto unmap;
+	qp->local_qp = *qp_offset;
+	return err;
+unmap:
+	scif_unmap_single(qp->local_buf, scifdev, local_size);
+	qp->local_buf = 0;
+kfree:
+	kfree(local_q);
+iounmap_1:
+	scif_iounmap(remote_q, remote_size, scifdev);
+	qp->outbound_q.rb_base = NULL;
+iounmap:
+	scif_iounmap(qp->remote_qp, sizeof(struct scif_qp), scifdev);
+	qp->remote_qp = NULL;
+	return err;
+}
+
+int scif_setup_qp_connect_response(struct scif_dev *scifdev,
+				   struct scif_qp *qp, u64 payload)
+{
+	int err = 0;
+	void *r_buf;
+	int remote_size;
+	phys_addr_t tmp_phys;
+
+	qp->remote_qp = scif_ioremap(payload, sizeof(struct scif_qp), scifdev);
+
+	if (!qp->remote_qp) {
+		err = -ENOMEM;
+		goto error;
+	}
+
+	if (qp->remote_qp->magic != SCIFEP_MAGIC) {
+		dev_err(&scifdev->sdev->dev,
+			"SCIFEP_MAGIC mismatch between self %d remote %d\n",
+			scif_dev[scif_info.nodeid].node, scifdev->node);
+		err = -ENODEV;
+		goto error;
+	}
+
+	tmp_phys = qp->remote_qp->local_buf;
+	remote_size = qp->remote_qp->inbound_q.size;
+	r_buf = scif_ioremap(tmp_phys, remote_size, scifdev);
+
+	if (!r_buf)
+		return -EIO;
+
+	qp->local_read = 0;
+	scif_rb_init(&qp->outbound_q,
+		     &qp->local_read,
+		     &qp->remote_qp->local_write,
+		     r_buf,
+		     get_count_order(remote_size));
+	/*
+	 * Because the node QP may already be processing an INIT message, set
+	 * the read pointer so the cached read offset isn't lost
+	 */
+	qp->remote_qp->local_read = qp->inbound_q.current_read_offset;
+	/*
+	 * resetup the inbound_q now that we know where the
+	 * inbound_read really is.
+	 */
+	scif_rb_init(&qp->inbound_q,
+		     &qp->remote_qp->local_read,
+		     &qp->local_write,
+		     qp->inbound_q.rb_base,
+		     get_count_order(qp->inbound_q.size));
+error:
+	return err;
+}
+
+static __always_inline void
+scif_send_msg_intr(struct scif_dev *scifdev)
+{
+	struct scif_hw_dev *sdev = scifdev->sdev;
+
+	if (scifdev_is_p2p(scifdev))
+		sdev->hw_ops->send_p2p_intr(sdev, scifdev->rdb, &scifdev->mmio);
+	else
+		sdev->hw_ops->send_intr(sdev, scifdev->rdb);
+}
+
+int scif_qp_response(phys_addr_t phys, struct scif_dev *scifdev)
+{
+	int err = 0;
+	struct scifmsg msg;
+
+	err = scif_setup_qp_connect_response(scifdev, scifdev->qpairs, phys);
+	if (!err) {
+		/*
+		 * Now that everything is setup and mapped, we're ready
+		 * to tell the peer about our queue's location
+		 */
+		msg.uop = SCIF_INIT;
+		msg.dst.node = scifdev->node;
+		err = scif_nodeqp_send(scifdev, &msg);
+	}
+	return err;
+}
+
+void scif_send_exit(struct scif_dev *scifdev)
+{
+	struct scifmsg msg;
+	int ret;
+
+	scifdev->exit = OP_IN_PROGRESS;
+	msg.uop = SCIF_EXIT;
+	msg.src.node = scif_info.nodeid;
+	msg.dst.node = scifdev->node;
+	ret = scif_nodeqp_send(scifdev, &msg);
+	if (ret)
+		goto done;
+	/* Wait for a SCIF_EXIT_ACK message */
+	wait_event_timeout(scif_info.exitwq, scifdev->exit == OP_COMPLETED,
+			   SCIF_NODE_ALIVE_TIMEOUT);
+done:
+	scifdev->exit = OP_IDLE;
+}
+
+int scif_setup_qp(struct scif_dev *scifdev)
+{
+	int err = 0;
+	int local_size;
+	struct scif_qp *qp;
+
+	local_size = SCIF_NODE_QP_SIZE;
+
+	qp = kzalloc(sizeof(*qp), GFP_KERNEL);
+	if (!qp) {
+		err = -ENOMEM;
+		return err;
+	}
+	qp->magic = SCIFEP_MAGIC;
+	scifdev->qpairs = qp;
+	err = scif_setup_qp_connect(qp, &scifdev->qp_dma_addr,
+				    local_size, scifdev);
+	if (err)
+		goto free_qp;
+	/*
+	 * We're as setup as we can be. The inbound_q is setup, w/o a usable
+	 * outbound q.  When we get a message, the read_ptr will be updated,
+	 * and we will pull the message.
+	 */
+	return err;
+free_qp:
+	kfree(scifdev->qpairs);
+	scifdev->qpairs = NULL;
+	return err;
+}
+
+static void scif_p2p_freesg(struct scatterlist *sg)
+{
+	kfree(sg);
+}
+
+static struct scatterlist *
+scif_p2p_setsg(phys_addr_t pa, int page_size, int page_cnt)
+{
+	struct scatterlist *sg;
+	struct page *page;
+	int i;
+
+	sg = kcalloc(page_cnt, sizeof(struct scatterlist), GFP_KERNEL);
+	if (!sg)
+		return NULL;
+	sg_init_table(sg, page_cnt);
+	for (i = 0; i < page_cnt; i++) {
+		page = pfn_to_page(pa >> PAGE_SHIFT);
+		sg_set_page(&sg[i], page, page_size, 0);
+		pa += page_size;
+	}
+	return sg;
+}
+
+/* Init p2p mappings required to access peerdev from scifdev */
+static struct scif_p2p_info *
+scif_init_p2p_info(struct scif_dev *scifdev, struct scif_dev *peerdev)
+{
+	struct scif_p2p_info *p2p;
+	int num_mmio_pages, num_aper_pages, sg_page_shift, err, num_aper_chunks;
+	struct scif_hw_dev *psdev = peerdev->sdev;
+	struct scif_hw_dev *sdev = scifdev->sdev;
+
+	num_mmio_pages = psdev->mmio->len >> PAGE_SHIFT;
+	num_aper_pages = psdev->aper->len >> PAGE_SHIFT;
+
+	p2p = kzalloc(sizeof(*p2p), GFP_KERNEL);
+	if (!p2p)
+		return NULL;
+	p2p->ppi_sg[SCIF_PPI_MMIO] = scif_p2p_setsg(psdev->mmio->pa,
+						    PAGE_SIZE, num_mmio_pages);
+	if (!p2p->ppi_sg[SCIF_PPI_MMIO])
+		goto free_p2p;
+	p2p->sg_nentries[SCIF_PPI_MMIO] = num_mmio_pages;
+	sg_page_shift = get_order(min(psdev->aper->len, (u64)(1 << 30)));
+	num_aper_chunks = num_aper_pages >> (sg_page_shift - PAGE_SHIFT);
+	p2p->ppi_sg[SCIF_PPI_APER] = scif_p2p_setsg(psdev->aper->pa,
+						    1 << sg_page_shift,
+						    num_aper_chunks);
+	p2p->sg_nentries[SCIF_PPI_APER] = num_aper_chunks;
+	err = dma_map_sg(&sdev->dev, p2p->ppi_sg[SCIF_PPI_MMIO],
+			 num_mmio_pages, PCI_DMA_BIDIRECTIONAL);
+	if (err != num_mmio_pages)
+		goto scif_p2p_free;
+	err = dma_map_sg(&sdev->dev, p2p->ppi_sg[SCIF_PPI_APER],
+			 num_aper_chunks, PCI_DMA_BIDIRECTIONAL);
+	if (err != num_aper_chunks)
+		goto dma_unmap;
+	p2p->ppi_da[SCIF_PPI_MMIO] = sg_dma_address(p2p->ppi_sg[SCIF_PPI_MMIO]);
+	p2p->ppi_da[SCIF_PPI_APER] = sg_dma_address(p2p->ppi_sg[SCIF_PPI_APER]);
+	p2p->ppi_len[SCIF_PPI_MMIO] = num_mmio_pages;
+	p2p->ppi_len[SCIF_PPI_APER] = num_aper_pages;
+	p2p->ppi_peer_id = peerdev->node;
+	return p2p;
+dma_unmap:
+	dma_unmap_sg(&sdev->dev, p2p->ppi_sg[SCIF_PPI_MMIO],
+		     p2p->sg_nentries[SCIF_PPI_MMIO], DMA_BIDIRECTIONAL);
+scif_p2p_free:
+	scif_p2p_freesg(p2p->ppi_sg[SCIF_PPI_MMIO]);
+	scif_p2p_freesg(p2p->ppi_sg[SCIF_PPI_APER]);
+free_p2p:
+	kfree(p2p);
+	return NULL;
+}
+
+/* Uninitialize and release resources from a p2p mapping */
+static void scif_deinit_p2p_info(struct scif_dev *scifdev,
+				 struct scif_p2p_info *p2p)
+{
+	struct scif_hw_dev *sdev = scifdev->sdev;
+
+	dma_unmap_sg(&sdev->dev, p2p->ppi_sg[SCIF_PPI_MMIO],
+		     p2p->sg_nentries[SCIF_PPI_MMIO], DMA_BIDIRECTIONAL);
+	dma_unmap_sg(&sdev->dev, p2p->ppi_sg[SCIF_PPI_APER],
+		     p2p->sg_nentries[SCIF_PPI_APER], DMA_BIDIRECTIONAL);
+	scif_p2p_freesg(p2p->ppi_sg[SCIF_PPI_MMIO]);
+	scif_p2p_freesg(p2p->ppi_sg[SCIF_PPI_APER]);
+	kfree(p2p);
+}
+
+/**
+ * scif_node_connect: Respond to SCIF_NODE_CONNECT interrupt message
+ * @dst: Destination node
+ *
+ * Connect the src and dst node by setting up the p2p connection
+ * between them. Management node here acts like a proxy.
+ */
+static void scif_node_connect(struct scif_dev *scifdev, int dst)
+{
+	struct scif_dev *dev_j = scifdev;
+	struct scif_dev *dev_i = NULL;
+	struct scif_p2p_info *p2p_ij = NULL;    /* bus addr for j from i */
+	struct scif_p2p_info *p2p_ji = NULL;    /* bus addr for i from j */
+	struct scif_p2p_info *p2p;
+	struct list_head *pos, *tmp;
+	struct scifmsg msg;
+	int err;
+	u64 tmppayload;
+
+	if (dst < 1 || dst > scif_info.maxid)
+		return;
+
+	dev_i = &scif_dev[dst];
+
+	if (!_scifdev_alive(dev_i))
+		return;
+	/*
+	 * If the p2p connection is already setup or in the process of setting
+	 * up then just ignore this request. The requested node will get
+	 * informed by SCIF_NODE_ADD_ACK or SCIF_NODE_ADD_NACK
+	 */
+	if (!list_empty(&dev_i->p2p)) {
+		list_for_each_safe(pos, tmp, &dev_i->p2p) {
+			p2p = list_entry(pos, struct scif_p2p_info, ppi_list);
+			if (p2p->ppi_peer_id == dev_j->node)
+				return;
+		}
+	}
+	p2p_ij = scif_init_p2p_info(dev_i, dev_j);
+	if (!p2p_ij)
+		return;
+	p2p_ji = scif_init_p2p_info(dev_j, dev_i);
+	if (!p2p_ji) {
+		scif_deinit_p2p_info(dev_i, p2p_ij);
+		return;
+	}
+	list_add_tail(&p2p_ij->ppi_list, &dev_i->p2p);
+	list_add_tail(&p2p_ji->ppi_list, &dev_j->p2p);
+
+	/*
+	 * Send a SCIF_NODE_ADD to dev_i, pass it its bus address
+	 * as seen from dev_j
+	 */
+	msg.uop = SCIF_NODE_ADD;
+	msg.src.node = dev_j->node;
+	msg.dst.node = dev_i->node;
+
+	msg.payload[0] = p2p_ji->ppi_da[SCIF_PPI_APER];
+	msg.payload[1] = p2p_ij->ppi_da[SCIF_PPI_MMIO];
+	msg.payload[2] = p2p_ij->ppi_da[SCIF_PPI_APER];
+	msg.payload[3] = p2p_ij->ppi_len[SCIF_PPI_APER] << PAGE_SHIFT;
+
+	err = scif_nodeqp_send(dev_i,  &msg);
+	if (err) {
+		dev_err(&scifdev->sdev->dev,
+			"%s %d error %d\n", __func__, __LINE__, err);
+		return;
+	}
+
+	/* Same as above but to dev_j */
+	msg.uop = SCIF_NODE_ADD;
+	msg.src.node = dev_i->node;
+	msg.dst.node = dev_j->node;
+
+	tmppayload = msg.payload[0];
+	msg.payload[0] = msg.payload[2];
+	msg.payload[2] = tmppayload;
+	msg.payload[1] = p2p_ji->ppi_da[SCIF_PPI_MMIO];
+	msg.payload[3] = p2p_ji->ppi_len[SCIF_PPI_APER] << PAGE_SHIFT;
+
+	scif_nodeqp_send(dev_j, &msg);
+}
+
+static void scif_p2p_setup(void)
+{
+	int i, j;
+
+	if (!scif_info.p2p_enable)
+		return;
+
+	for (i = 1; i <= scif_info.maxid; i++)
+		if (!_scifdev_alive(&scif_dev[i]))
+			return;
+
+	for (i = 1; i <= scif_info.maxid; i++) {
+		for (j = 1; j <= scif_info.maxid; j++) {
+			struct scif_dev *scifdev = &scif_dev[i];
+
+			if (i == j)
+				continue;
+			scif_node_connect(scifdev, j);
+		}
+	}
+}
+
+static char *message_types[] = {"BAD",
+				"INIT",
+				"EXIT",
+				"SCIF_EXIT_ACK",
+				"SCIF_NODE_ADD",
+				"SCIF_NODE_ADD_ACK",
+				"SCIF_NODE_ADD_NACK",
+				"REMOVE_NODE",
+				"REMOVE_NODE_ACK",
+				"CNCT_REQ",
+				"CNCT_GNT",
+				"CNCT_GNTACK",
+				"CNCT_GNTNACK",
+				"CNCT_REJ",
+				"DISCNCT",
+				"DISCNT_ACK",
+				"CLIENT_SENT",
+				"CLIENT_RCVD",
+				"SCIF_GET_NODE_INFO",
+				"REGISTER",
+				"REGISTER_ACK",
+				"REGISTER_NACK",
+				"UNREGISTER",
+				"UNREGISTER_ACK",
+				"UNREGISTER_NACK",
+				"ALLOC_REQ",
+				"ALLOC_GNT",
+				"ALLOC_REJ",
+				"FREE_PHYS",
+				"FREE_VIRT",
+				"MUNMAP",
+				"MARK",
+				"MARK_ACK",
+				"MARK_NACK",
+				"WAIT",
+				"WAIT_ACK",
+				"WAIT_NACK",
+				"SIGNAL_LOCAL",
+				"SIGNAL_REMOTE",
+				"SIG_ACK",
+				"SIG_NACK"};
+
+static void
+scif_display_message(struct scif_dev *scifdev, struct scifmsg *msg,
+		     const char *label)
+{
+	if (!scif_info.en_msg_log)
+		return;
+	if (msg->uop > SCIF_MAX_MSG) {
+		dev_err(&scifdev->sdev->dev,
+			"%s: unknown msg type %d\n", label, msg->uop);
+		return;
+	}
+	dev_info(&scifdev->sdev->dev,
+		 "%s: msg type %s, src %d:%d, dest %d:%d payload 0x%llx:0x%llx:0x%llx:0x%llx\n",
+		 label, message_types[msg->uop], msg->src.node, msg->src.port,
+		 msg->dst.node, msg->dst.port, msg->payload[0], msg->payload[1],
+		 msg->payload[2], msg->payload[3]);
+}
+
+int _scif_nodeqp_send(struct scif_dev *scifdev, struct scifmsg *msg)
+{
+	struct scif_qp *qp = scifdev->qpairs;
+	int err = -ENOMEM, loop_cnt = 0;
+
+	scif_display_message(scifdev, msg, "Sent");
+	if (!qp) {
+		err = -EINVAL;
+		goto error;
+	}
+	spin_lock(&qp->send_lock);
+
+	while ((err = scif_rb_write(&qp->outbound_q,
+				    msg, sizeof(struct scifmsg)))) {
+		mdelay(1);
+#define SCIF_NODEQP_SEND_TO_MSEC (3 * 1000)
+		if (loop_cnt++ > (SCIF_NODEQP_SEND_TO_MSEC)) {
+			err = -ENODEV;
+			break;
+		}
+	}
+	if (!err)
+		scif_rb_commit(&qp->outbound_q);
+	spin_unlock(&qp->send_lock);
+	if (!err) {
+		if (scifdev_self(scifdev))
+			/*
+			 * For loopback we need to emulate an interrupt by
+			 * queuing work for the queue handling real node
+			 * Qp interrupts.
+			 */
+			queue_work(scifdev->intr_wq, &scifdev->intr_bh);
+		else
+			scif_send_msg_intr(scifdev);
+	}
+error:
+	if (err)
+		dev_dbg(&scifdev->sdev->dev,
+			"%s %d error %d uop %d\n",
+			 __func__, __LINE__, err, msg->uop);
+	return err;
+}
+
+/**
+ * scif_nodeqp_send - Send a message on the node queue pair
+ * @scifdev: Scif Device.
+ * @msg: The message to be sent.
+ */
+int scif_nodeqp_send(struct scif_dev *scifdev, struct scifmsg *msg)
+{
+	int err;
+	struct device *spdev = NULL;
+
+	if (msg->uop > SCIF_EXIT_ACK) {
+		/* Dont send messages once the exit flow has begun */
+		if (OP_IDLE != scifdev->exit)
+			return -ENODEV;
+		spdev = scif_get_peer_dev(scifdev);
+		if (IS_ERR(spdev)) {
+			err = PTR_ERR(spdev);
+			return err;
+		}
+	}
+	err = _scif_nodeqp_send(scifdev, msg);
+	if (msg->uop > SCIF_EXIT_ACK)
+		scif_put_peer_dev(spdev);
+	return err;
+}
+
+/*
+ * scif_misc_handler:
+ *
+ * Work queue handler for servicing miscellaneous SCIF tasks.
+ * Examples include:
+ * 1) Remote fence requests.
+ * 2) Destruction of temporary registered windows
+ *    created during scif_vreadfrom()/scif_vwriteto().
+ * 3) Cleanup of zombie endpoints.
+ */
+void scif_misc_handler(struct work_struct *work)
+{
+	scif_rma_handle_remote_fences();
+	scif_rma_destroy_windows();
+	scif_rma_destroy_tcw_invalid();
+	scif_cleanup_zombie_epd();
+}
+
+/**
+ * scif_init() - Respond to SCIF_INIT interrupt message
+ * @scifdev:    Remote SCIF device node
+ * @msg:        Interrupt message
+ */
+static __always_inline void
+scif_init(struct scif_dev *scifdev, struct scifmsg *msg)
+{
+	/*
+	 * Allow the thread waiting for device page updates for the peer QP DMA
+	 * address to complete initializing the inbound_q.
+	 */
+	flush_delayed_work(&scifdev->qp_dwork);
+
+	scif_peer_register_device(scifdev);
+
+	if (scif_is_mgmt_node()) {
+		mutex_lock(&scif_info.conflock);
+		scif_p2p_setup();
+		mutex_unlock(&scif_info.conflock);
+	}
+}
+
+/**
+ * scif_exit() - Respond to SCIF_EXIT interrupt message
+ * @scifdev:    Remote SCIF device node
+ * @msg:        Interrupt message
+ *
+ * This function stops the SCIF interface for the node which sent
+ * the SCIF_EXIT message and starts waiting for that node to
+ * resetup the queue pair again.
+ */
+static __always_inline void
+scif_exit(struct scif_dev *scifdev, struct scifmsg *unused)
+{
+	scifdev->exit_ack_pending = true;
+	if (scif_is_mgmt_node())
+		scif_disconnect_node(scifdev->node, false);
+	else
+		scif_stop(scifdev);
+	schedule_delayed_work(&scifdev->qp_dwork,
+			      msecs_to_jiffies(1000));
+}
+
+/**
+ * scif_exitack() - Respond to SCIF_EXIT_ACK interrupt message
+ * @scifdev:    Remote SCIF device node
+ * @msg:        Interrupt message
+ *
+ */
+static __always_inline void
+scif_exit_ack(struct scif_dev *scifdev, struct scifmsg *unused)
+{
+	scifdev->exit = OP_COMPLETED;
+	wake_up(&scif_info.exitwq);
+}
+
+/**
+ * scif_node_add() - Respond to SCIF_NODE_ADD interrupt message
+ * @scifdev:    Remote SCIF device node
+ * @msg:        Interrupt message
+ *
+ * When the mgmt node driver has finished initializing a MIC node queue pair it
+ * marks the node as online. It then looks for all currently online MIC cards
+ * and send a SCIF_NODE_ADD message to identify the ID of the new card for
+ * peer to peer initialization
+ *
+ * The local node allocates its incoming queue and sends its address in the
+ * SCIF_NODE_ADD_ACK message back to the mgmt node, the mgmt node "reflects"
+ * this message to the new node
+ */
+static __always_inline void
+scif_node_add(struct scif_dev *scifdev, struct scifmsg *msg)
+{
+	struct scif_dev *newdev;
+	dma_addr_t qp_offset;
+	int qp_connect;
+	struct scif_hw_dev *sdev;
+
+	dev_dbg(&scifdev->sdev->dev,
+		"Scifdev %d:%d received NODE_ADD msg for node %d\n",
+		scifdev->node, msg->dst.node, msg->src.node);
+	dev_dbg(&scifdev->sdev->dev,
+		"Remote address for this node's aperture %llx\n",
+		msg->payload[0]);
+	newdev = &scif_dev[msg->src.node];
+	newdev->node = msg->src.node;
+	newdev->sdev = scif_dev[SCIF_MGMT_NODE].sdev;
+	sdev = newdev->sdev;
+
+	if (scif_setup_intr_wq(newdev)) {
+		dev_err(&scifdev->sdev->dev,
+			"failed to setup interrupts for %d\n", msg->src.node);
+		goto interrupt_setup_error;
+	}
+	newdev->mmio.va = ioremap_nocache(msg->payload[1], sdev->mmio->len);
+	if (!newdev->mmio.va) {
+		dev_err(&scifdev->sdev->dev,
+			"failed to map mmio for %d\n", msg->src.node);
+		goto mmio_map_error;
+	}
+	newdev->qpairs = kzalloc(sizeof(*newdev->qpairs), GFP_KERNEL);
+	if (!newdev->qpairs)
+		goto qp_alloc_error;
+	/*
+	 * Set the base address of the remote node's memory since it gets
+	 * added to qp_offset
+	 */
+	newdev->base_addr = msg->payload[0];
+
+	qp_connect = scif_setup_qp_connect(newdev->qpairs, &qp_offset,
+					   SCIF_NODE_QP_SIZE, newdev);
+	if (qp_connect) {
+		dev_err(&scifdev->sdev->dev,
+			"failed to setup qp_connect %d\n", qp_connect);
+		goto qp_connect_error;
+	}
+
+	newdev->db = sdev->hw_ops->next_db(sdev);
+	newdev->cookie = sdev->hw_ops->request_irq(sdev, scif_intr_handler,
+						   "SCIF_INTR", newdev,
+						   newdev->db);
+	if (IS_ERR(newdev->cookie))
+		goto qp_connect_error;
+	newdev->qpairs->magic = SCIFEP_MAGIC;
+	newdev->qpairs->qp_state = SCIF_QP_OFFLINE;
+
+	msg->uop = SCIF_NODE_ADD_ACK;
+	msg->dst.node = msg->src.node;
+	msg->src.node = scif_info.nodeid;
+	msg->payload[0] = qp_offset;
+	msg->payload[2] = newdev->db;
+	scif_nodeqp_send(&scif_dev[SCIF_MGMT_NODE], msg);
+	return;
+qp_connect_error:
+	kfree(newdev->qpairs);
+	newdev->qpairs = NULL;
+qp_alloc_error:
+	iounmap(newdev->mmio.va);
+	newdev->mmio.va = NULL;
+mmio_map_error:
+interrupt_setup_error:
+	dev_err(&scifdev->sdev->dev,
+		"node add failed for node %d\n", msg->src.node);
+	msg->uop = SCIF_NODE_ADD_NACK;
+	msg->dst.node = msg->src.node;
+	msg->src.node = scif_info.nodeid;
+	scif_nodeqp_send(&scif_dev[SCIF_MGMT_NODE], msg);
+}
+
+void scif_poll_qp_state(struct work_struct *work)
+{
+#define SCIF_NODE_QP_RETRY 100
+#define SCIF_NODE_QP_TIMEOUT 100
+	struct scif_dev *peerdev = container_of(work, struct scif_dev,
+							p2p_dwork.work);
+	struct scif_qp *qp = &peerdev->qpairs[0];
+
+	if (qp->qp_state != SCIF_QP_ONLINE ||
+	    qp->remote_qp->qp_state != SCIF_QP_ONLINE) {
+		if (peerdev->p2p_retry++ == SCIF_NODE_QP_RETRY) {
+			dev_err(&peerdev->sdev->dev,
+				"Warning: QP check timeout with state %d\n",
+				qp->qp_state);
+			goto timeout;
+		}
+		schedule_delayed_work(&peerdev->p2p_dwork,
+				      msecs_to_jiffies(SCIF_NODE_QP_TIMEOUT));
+		return;
+	}
+	return;
+timeout:
+	dev_err(&peerdev->sdev->dev,
+		"%s %d remote node %d offline,  state = 0x%x\n",
+		__func__, __LINE__, peerdev->node, qp->qp_state);
+	qp->remote_qp->qp_state = SCIF_QP_OFFLINE;
+	scif_peer_unregister_device(peerdev);
+	scif_cleanup_scifdev(peerdev);
+}
+
+/**
+ * scif_node_add_ack() - Respond to SCIF_NODE_ADD_ACK interrupt message
+ * @scifdev:    Remote SCIF device node
+ * @msg:        Interrupt message
+ *
+ * After a MIC node receives the SCIF_NODE_ADD_ACK message it send this
+ * message to the mgmt node to confirm the sequence is finished.
+ *
+ */
+static __always_inline void
+scif_node_add_ack(struct scif_dev *scifdev, struct scifmsg *msg)
+{
+	struct scif_dev *peerdev;
+	struct scif_qp *qp;
+	struct scif_dev *dst_dev = &scif_dev[msg->dst.node];
+
+	dev_dbg(&scifdev->sdev->dev,
+		"Scifdev %d received SCIF_NODE_ADD_ACK msg src %d dst %d\n",
+		scifdev->node, msg->src.node, msg->dst.node);
+	dev_dbg(&scifdev->sdev->dev,
+		"payload %llx %llx %llx %llx\n", msg->payload[0],
+		msg->payload[1], msg->payload[2], msg->payload[3]);
+	if (scif_is_mgmt_node()) {
+		/*
+		 * the lock serializes with scif_qp_response_ack. The mgmt node
+		 * is forwarding the NODE_ADD_ACK message from src to dst we
+		 * need to make sure that the dst has already received a
+		 * NODE_ADD for src and setup its end of the qp to dst
+		 */
+		mutex_lock(&scif_info.conflock);
+		msg->payload[1] = scif_info.maxid;
+		scif_nodeqp_send(dst_dev, msg);
+		mutex_unlock(&scif_info.conflock);
+		return;
+	}
+	peerdev = &scif_dev[msg->src.node];
+	peerdev->sdev = scif_dev[SCIF_MGMT_NODE].sdev;
+	peerdev->node = msg->src.node;
+
+	qp = &peerdev->qpairs[0];
+
+	if ((scif_setup_qp_connect_response(peerdev, &peerdev->qpairs[0],
+					    msg->payload[0])))
+		goto local_error;
+	peerdev->rdb = msg->payload[2];
+	qp->remote_qp->qp_state = SCIF_QP_ONLINE;
+
+	scif_peer_register_device(peerdev);
+
+	schedule_delayed_work(&peerdev->p2p_dwork, 0);
+	return;
+local_error:
+	scif_cleanup_scifdev(peerdev);
+}
+
+/**
+ * scif_node_add_nack: Respond to SCIF_NODE_ADD_NACK interrupt message
+ * @msg:        Interrupt message
+ *
+ * SCIF_NODE_ADD failed, so inform the waiting wq.
+ */
+static __always_inline void
+scif_node_add_nack(struct scif_dev *scifdev, struct scifmsg *msg)
+{
+	if (scif_is_mgmt_node()) {
+		struct scif_dev *dst_dev = &scif_dev[msg->dst.node];
+
+		dev_dbg(&scifdev->sdev->dev,
+			"SCIF_NODE_ADD_NACK received from %d\n", scifdev->node);
+		scif_nodeqp_send(dst_dev, msg);
+	}
+}
+
+/*
+ * scif_node_remove: Handle SCIF_NODE_REMOVE message
+ * @msg: Interrupt message
+ *
+ * Handle node removal.
+ */
+static __always_inline void
+scif_node_remove(struct scif_dev *scifdev, struct scifmsg *msg)
+{
+	int node = msg->payload[0];
+	struct scif_dev *scdev = &scif_dev[node];
+
+	scdev->node_remove_ack_pending = true;
+	scif_handle_remove_node(node);
+}
+
+/*
+ * scif_node_remove_ack: Handle SCIF_NODE_REMOVE_ACK message
+ * @msg: Interrupt message
+ *
+ * The peer has acked a SCIF_NODE_REMOVE message.
+ */
+static __always_inline void
+scif_node_remove_ack(struct scif_dev *scifdev, struct scifmsg *msg)
+{
+	struct scif_dev *sdev = &scif_dev[msg->payload[0]];
+
+	atomic_inc(&sdev->disconn_rescnt);
+	wake_up(&sdev->disconn_wq);
+}
+
+/**
+ * scif_get_node_info: Respond to SCIF_GET_NODE_INFO interrupt message
+ * @msg:        Interrupt message
+ *
+ * Retrieve node info i.e maxid and total from the mgmt node.
+ */
+static __always_inline void
+scif_get_node_info_resp(struct scif_dev *scifdev, struct scifmsg *msg)
+{
+	if (scif_is_mgmt_node()) {
+		swap(msg->dst.node, msg->src.node);
+		mutex_lock(&scif_info.conflock);
+		msg->payload[1] = scif_info.maxid;
+		msg->payload[2] = scif_info.total;
+		mutex_unlock(&scif_info.conflock);
+		scif_nodeqp_send(scifdev, msg);
+	} else {
+		struct completion *node_info =
+			(struct completion *)msg->payload[3];
+
+		mutex_lock(&scif_info.conflock);
+		scif_info.maxid = msg->payload[1];
+		scif_info.total = msg->payload[2];
+		complete_all(node_info);
+		mutex_unlock(&scif_info.conflock);
+	}
+}
+
+static void
+scif_msg_unknown(struct scif_dev *scifdev, struct scifmsg *msg)
+{
+	/* Bogus Node Qp Message? */
+	dev_err(&scifdev->sdev->dev,
+		"Unknown message 0x%xn scifdev->node 0x%x\n",
+		msg->uop, scifdev->node);
+}
+
+static void (*scif_intr_func[SCIF_MAX_MSG + 1])
+	    (struct scif_dev *, struct scifmsg *msg) = {
+	scif_msg_unknown,	/* Error */
+	scif_init,		/* SCIF_INIT */
+	scif_exit,		/* SCIF_EXIT */
+	scif_exit_ack,		/* SCIF_EXIT_ACK */
+	scif_node_add,		/* SCIF_NODE_ADD */
+	scif_node_add_ack,	/* SCIF_NODE_ADD_ACK */
+	scif_node_add_nack,	/* SCIF_NODE_ADD_NACK */
+	scif_node_remove,	/* SCIF_NODE_REMOVE */
+	scif_node_remove_ack,	/* SCIF_NODE_REMOVE_ACK */
+	scif_cnctreq,		/* SCIF_CNCT_REQ */
+	scif_cnctgnt,		/* SCIF_CNCT_GNT */
+	scif_cnctgnt_ack,	/* SCIF_CNCT_GNTACK */
+	scif_cnctgnt_nack,	/* SCIF_CNCT_GNTNACK */
+	scif_cnctrej,		/* SCIF_CNCT_REJ */
+	scif_discnct,		/* SCIF_DISCNCT */
+	scif_discnt_ack,	/* SCIF_DISCNT_ACK */
+	scif_clientsend,	/* SCIF_CLIENT_SENT */
+	scif_clientrcvd,	/* SCIF_CLIENT_RCVD */
+	scif_get_node_info_resp,/* SCIF_GET_NODE_INFO */
+	scif_recv_reg,		/* SCIF_REGISTER */
+	scif_recv_reg_ack,	/* SCIF_REGISTER_ACK */
+	scif_recv_reg_nack,	/* SCIF_REGISTER_NACK */
+	scif_recv_unreg,	/* SCIF_UNREGISTER */
+	scif_recv_unreg_ack,	/* SCIF_UNREGISTER_ACK */
+	scif_recv_unreg_nack,	/* SCIF_UNREGISTER_NACK */
+	scif_alloc_req,		/* SCIF_ALLOC_REQ */
+	scif_alloc_gnt_rej,	/* SCIF_ALLOC_GNT */
+	scif_alloc_gnt_rej,	/* SCIF_ALLOC_REJ */
+	scif_free_virt,		/* SCIF_FREE_VIRT */
+	scif_recv_munmap,	/* SCIF_MUNMAP */
+	scif_recv_mark,		/* SCIF_MARK */
+	scif_recv_mark_resp,	/* SCIF_MARK_ACK */
+	scif_recv_mark_resp,	/* SCIF_MARK_NACK */
+	scif_recv_wait,		/* SCIF_WAIT */
+	scif_recv_wait_resp,	/* SCIF_WAIT_ACK */
+	scif_recv_wait_resp,	/* SCIF_WAIT_NACK */
+	scif_recv_sig_local,	/* SCIF_SIG_LOCAL */
+	scif_recv_sig_remote,	/* SCIF_SIG_REMOTE */
+	scif_recv_sig_resp,	/* SCIF_SIG_ACK */
+	scif_recv_sig_resp,	/* SCIF_SIG_NACK */
+};
+
+/**
+ * scif_nodeqp_msg_handler() - Common handler for node messages
+ * @scifdev: Remote device to respond to
+ * @qp: Remote memory pointer
+ * @msg: The message to be handled.
+ *
+ * This routine calls the appropriate routine to handle a Node Qp
+ * message receipt
+ */
+static int scif_max_msg_id = SCIF_MAX_MSG;
+
+static void
+scif_nodeqp_msg_handler(struct scif_dev *scifdev,
+			struct scif_qp *qp, struct scifmsg *msg)
+{
+	scif_display_message(scifdev, msg, "Rcvd");
+
+	if (msg->uop > (u32)scif_max_msg_id) {
+		/* Bogus Node Qp Message? */
+		dev_err(&scifdev->sdev->dev,
+			"Unknown message 0x%xn scifdev->node 0x%x\n",
+			msg->uop, scifdev->node);
+		return;
+	}
+
+	scif_intr_func[msg->uop](scifdev, msg);
+}
+
+/**
+ * scif_nodeqp_intrhandler() - Interrupt handler for node messages
+ * @scifdev:    Remote device to respond to
+ * @qp:         Remote memory pointer
+ *
+ * This routine is triggered by the interrupt mechanism.  It reads
+ * messages from the node queue RB and calls the Node QP Message handling
+ * routine.
+ */
+void scif_nodeqp_intrhandler(struct scif_dev *scifdev, struct scif_qp *qp)
+{
+	struct scifmsg msg;
+	int read_size;
+
+	do {
+		read_size = scif_rb_get_next(&qp->inbound_q, &msg, sizeof(msg));
+		if (!read_size)
+			break;
+		scif_nodeqp_msg_handler(scifdev, qp, &msg);
+		/*
+		 * The node queue pair is unmapped so skip the read pointer
+		 * update after receipt of a SCIF_EXIT_ACK
+		 */
+		if (SCIF_EXIT_ACK == msg.uop)
+			break;
+		scif_rb_update_read_ptr(&qp->inbound_q);
+	} while (1);
+}
+
+/**
+ * scif_loopb_wq_handler - Loopback Workqueue Handler.
+ * @work: loop back work
+ *
+ * This work queue routine is invoked by the loopback work queue handler.
+ * It grabs the recv lock, dequeues any available messages from the head
+ * of the loopback message list, calls the node QP message handler,
+ * waits for it to return, then frees up this message and dequeues more
+ * elements of the list if available.
+ */
+static void scif_loopb_wq_handler(struct work_struct *unused)
+{
+	struct scif_dev *scifdev = scif_info.loopb_dev;
+	struct scif_qp *qp = scifdev->qpairs;
+	struct scif_loopb_msg *msg;
+
+	do {
+		msg = NULL;
+		spin_lock(&qp->recv_lock);
+		if (!list_empty(&scif_info.loopb_recv_q)) {
+			msg = list_first_entry(&scif_info.loopb_recv_q,
+					       struct scif_loopb_msg,
+					       list);
+			list_del(&msg->list);
+		}
+		spin_unlock(&qp->recv_lock);
+
+		if (msg) {
+			scif_nodeqp_msg_handler(scifdev, qp, &msg->msg);
+			kfree(msg);
+		}
+	} while (msg);
+}
+
+/**
+ * scif_loopb_msg_handler() - Workqueue handler for loopback messages.
+ * @scifdev: SCIF device
+ * @qp: Queue pair.
+ *
+ * This work queue routine is triggered when a loopback message is received.
+ *
+ * We need special handling for receiving Node Qp messages on a loopback SCIF
+ * device via two workqueues for receiving messages.
+ *
+ * The reason we need the extra workqueue which is not required with *normal*
+ * non-loopback SCIF devices is the potential classic deadlock described below:
+ *
+ * Thread A tries to send a message on a loopback SCIF device and blocks since
+ * there is no space in the RB while it has the send_lock held or another
+ * lock called lock X for example.
+ *
+ * Thread B: The Loopback Node QP message receive workqueue receives the message
+ * and tries to send a message (eg an ACK) to the loopback SCIF device. It tries
+ * to grab the send lock again or lock X and deadlocks with Thread A. The RB
+ * cannot be drained any further due to this classic deadlock.
+ *
+ * In order to avoid deadlocks as mentioned above we have an extra level of
+ * indirection achieved by having two workqueues.
+ * 1) The first workqueue whose handler is scif_loopb_msg_handler reads
+ * messages from the Node QP RB, adds them to a list and queues work for the
+ * second workqueue.
+ *
+ * 2) The second workqueue whose handler is scif_loopb_wq_handler dequeues
+ * messages from the list, handles them, frees up the memory and dequeues
+ * more elements from the list if possible.
+ */
+int
+scif_loopb_msg_handler(struct scif_dev *scifdev, struct scif_qp *qp)
+{
+	int read_size;
+	struct scif_loopb_msg *msg;
+
+	do {
+		msg = kmalloc(sizeof(*msg), GFP_KERNEL);
+		if (!msg)
+			return -ENOMEM;
+		read_size = scif_rb_get_next(&qp->inbound_q, &msg->msg,
+					     sizeof(struct scifmsg));
+		if (read_size != sizeof(struct scifmsg)) {
+			kfree(msg);
+			scif_rb_update_read_ptr(&qp->inbound_q);
+			break;
+		}
+		spin_lock(&qp->recv_lock);
+		list_add_tail(&msg->list, &scif_info.loopb_recv_q);
+		spin_unlock(&qp->recv_lock);
+		queue_work(scif_info.loopb_wq, &scif_info.loopb_work);
+		scif_rb_update_read_ptr(&qp->inbound_q);
+	} while (read_size == sizeof(struct scifmsg));
+	return read_size;
+}
+
+/**
+ * scif_setup_loopback_qp - One time setup work for Loopback Node Qp.
+ * @scifdev: SCIF device
+ *
+ * Sets up the required loopback workqueues, queue pairs and ring buffers
+ */
+int scif_setup_loopback_qp(struct scif_dev *scifdev)
+{
+	int err = 0;
+	void *local_q;
+	struct scif_qp *qp;
+
+	err = scif_setup_intr_wq(scifdev);
+	if (err)
+		goto exit;
+	INIT_LIST_HEAD(&scif_info.loopb_recv_q);
+	snprintf(scif_info.loopb_wqname, sizeof(scif_info.loopb_wqname),
+		 "SCIF LOOPB %d", scifdev->node);
+	scif_info.loopb_wq =
+		alloc_ordered_workqueue(scif_info.loopb_wqname, 0);
+	if (!scif_info.loopb_wq) {
+		err = -ENOMEM;
+		goto destroy_intr;
+	}
+	INIT_WORK(&scif_info.loopb_work, scif_loopb_wq_handler);
+	/* Allocate Self Qpair */
+	scifdev->qpairs = kzalloc(sizeof(*scifdev->qpairs), GFP_KERNEL);
+	if (!scifdev->qpairs) {
+		err = -ENOMEM;
+		goto destroy_loopb_wq;
+	}
+
+	qp = scifdev->qpairs;
+	qp->magic = SCIFEP_MAGIC;
+	spin_lock_init(&qp->send_lock);
+	spin_lock_init(&qp->recv_lock);
+
+	local_q = kzalloc(SCIF_NODE_QP_SIZE, GFP_KERNEL);
+	if (!local_q) {
+		err = -ENOMEM;
+		goto free_qpairs;
+	}
+	/*
+	 * For loopback the inbound_q and outbound_q are essentially the same
+	 * since the Node sends a message on the loopback interface to the
+	 * outbound_q which is then received on the inbound_q.
+	 */
+	scif_rb_init(&qp->outbound_q,
+		     &qp->local_read,
+		     &qp->local_write,
+		     local_q, get_count_order(SCIF_NODE_QP_SIZE));
+
+	scif_rb_init(&qp->inbound_q,
+		     &qp->local_read,
+		     &qp->local_write,
+		     local_q, get_count_order(SCIF_NODE_QP_SIZE));
+	scif_info.nodeid = scifdev->node;
+
+	scif_peer_register_device(scifdev);
+
+	scif_info.loopb_dev = scifdev;
+	return err;
+free_qpairs:
+	kfree(scifdev->qpairs);
+destroy_loopb_wq:
+	destroy_workqueue(scif_info.loopb_wq);
+destroy_intr:
+	scif_destroy_intr_wq(scifdev);
+exit:
+	return err;
+}
+
+/**
+ * scif_destroy_loopback_qp - One time uninit work for Loopback Node Qp
+ * @scifdev: SCIF device
+ *
+ * Destroys the workqueues and frees up the Ring Buffer and Queue Pair memory.
+ */
+int scif_destroy_loopback_qp(struct scif_dev *scifdev)
+{
+	scif_peer_unregister_device(scifdev);
+	destroy_workqueue(scif_info.loopb_wq);
+	scif_destroy_intr_wq(scifdev);
+	kfree(scifdev->qpairs->outbound_q.rb_base);
+	kfree(scifdev->qpairs);
+	scifdev->sdev = NULL;
+	scif_info.loopb_dev = NULL;
+	return 0;
+}
+
+void scif_destroy_p2p(struct scif_dev *scifdev)
+{
+	struct scif_dev *peer_dev;
+	struct scif_p2p_info *p2p;
+	struct list_head *pos, *tmp;
+	int bd;
+
+	mutex_lock(&scif_info.conflock);
+	/* Free P2P mappings in the given node for all its peer nodes */
+	list_for_each_safe(pos, tmp, &scifdev->p2p) {
+		p2p = list_entry(pos, struct scif_p2p_info, ppi_list);
+		dma_unmap_sg(&scifdev->sdev->dev, p2p->ppi_sg[SCIF_PPI_MMIO],
+			     p2p->sg_nentries[SCIF_PPI_MMIO],
+			     DMA_BIDIRECTIONAL);
+		dma_unmap_sg(&scifdev->sdev->dev, p2p->ppi_sg[SCIF_PPI_APER],
+			     p2p->sg_nentries[SCIF_PPI_APER],
+			     DMA_BIDIRECTIONAL);
+		scif_p2p_freesg(p2p->ppi_sg[SCIF_PPI_MMIO]);
+		scif_p2p_freesg(p2p->ppi_sg[SCIF_PPI_APER]);
+		list_del(pos);
+		kfree(p2p);
+	}
+
+	/* Free P2P mapping created in the peer nodes for the given node */
+	for (bd = SCIF_MGMT_NODE + 1; bd <= scif_info.maxid; bd++) {
+		peer_dev = &scif_dev[bd];
+		list_for_each_safe(pos, tmp, &peer_dev->p2p) {
+			p2p = list_entry(pos, struct scif_p2p_info, ppi_list);
+			if (p2p->ppi_peer_id == scifdev->node) {
+				dma_unmap_sg(&peer_dev->sdev->dev,
+					     p2p->ppi_sg[SCIF_PPI_MMIO],
+					     p2p->sg_nentries[SCIF_PPI_MMIO],
+					     DMA_BIDIRECTIONAL);
+				dma_unmap_sg(&peer_dev->sdev->dev,
+					     p2p->ppi_sg[SCIF_PPI_APER],
+					     p2p->sg_nentries[SCIF_PPI_APER],
+					     DMA_BIDIRECTIONAL);
+				scif_p2p_freesg(p2p->ppi_sg[SCIF_PPI_MMIO]);
+				scif_p2p_freesg(p2p->ppi_sg[SCIF_PPI_APER]);
+				list_del(pos);
+				kfree(p2p);
+			}
+		}
+	}
+	mutex_unlock(&scif_info.conflock);
+}