// SPDX-License-Identifier: GPL-2.0-only
/*
 * Intel MIC Platform Software Stack (MPSS)
 *
 * Copyright(c) 2014 Intel Corporation.
 *
 * 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
 * @scifdev: SCIF device
 * @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) {
                /* Don't 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
 * @unused:     Interrupt message (unused)
 *
 * 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
 * @unused:     Interrupt message (unused)
 *
 */
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(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
 * @scifdev:    Remote SCIF device node
 * @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
 * @scifdev:    Remote SCIF device node
 * @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
 * @scifdev:    Remote SCIF device node
 * @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
 * @scifdev:    Remote SCIF device node
 * @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 */
};

static int scif_max_msg_id = SCIF_MAX_MSG;
/**
 * 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 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.
 * @unused: loop back work (unused)
 *
 * 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);
}