text: /*
   * Copyright (c) 2012-2016 VMware, Inc.  All rights reserved.
   *
   * This program is free software; you can redistribute it and/or
   * modify it under the terms of EITHER the GNU General Public License
   * version 2 as published by the Free Software Foundation or the BSD
   * 2-Clause License. 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 version 2 for more details at
   * http://www.gnu.org/licenses/old-licenses/gpl-2.0.en.html.
   *
   * You should have received a copy of the GNU General Public License
   * along with this program available in the file COPYING in the main
   * directory of this source tree.
   *
   * The BSD 2-Clause License
   *
   *     Redistribution and use in source and binary forms, with or
   *     without modification, are permitted provided that the following
   *     conditions are met:
   *
   *      - Redistributions of source code must retain the above
   *        copyright notice, this list of conditions and the following
   *        disclaimer.
   *
   *      - Redistributions in binary form must reproduce the above
   *        copyright notice, this list of conditions and the following
   *        disclaimer in the documentation and/or other materials
   *        provided with the distribution.
   *
   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
   * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
   * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
   * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
   * COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
   * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
   * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
   * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
   * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
   * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
   * OF THE POSSIBILITY OF SUCH DAMAGE.
   */
  
  #include <asm/page.h>
  #include <linux/io.h>
  #include <linux/wait.h>
  #include <rdma/ib_addr.h>
  #include <rdma/ib_smi.h>
  #include <rdma/ib_user_verbs.h>
  
  #include "pvrdma.h"
  
  /**
   * pvrdma_req_notify_cq - request notification for a completion queue
   * @ibcq: the completion queue
   * @notify_flags: notification flags
   *
   * @return: 0 for success.
   */
  int pvrdma_req_notify_cq(struct ib_cq *ibcq,
  			 enum ib_cq_notify_flags notify_flags)
  {
  	struct pvrdma_dev *dev = to_vdev(ibcq->device);
  	struct pvrdma_cq *cq = to_vcq(ibcq);
  	u32 val = cq->cq_handle;
  	unsigned long flags;
  	int has_data = 0;
  
  	val |= (notify_flags & IB_CQ_SOLICITED_MASK) == IB_CQ_SOLICITED ?
  		PVRDMA_UAR_CQ_ARM_SOL : PVRDMA_UAR_CQ_ARM;
  
  	spin_lock_irqsave(&cq->cq_lock, flags);
  
  	pvrdma_write_uar_cq(dev, val);
  
  	if (notify_flags & IB_CQ_REPORT_MISSED_EVENTS) {
  		unsigned int head;
  
  		has_data = pvrdma_idx_ring_has_data(&cq->ring_state->rx,
  						    cq->ibcq.cqe, &head);
  		if (unlikely(has_data == PVRDMA_INVALID_IDX))
  			dev_err(&dev->pdev->dev, "CQ ring state invalid\n");
  	}
  
  	spin_unlock_irqrestore(&cq->cq_lock, flags);
  
  	return has_data;
  }
  
  /**
   * pvrdma_create_cq - create completion queue
   * @ibdev: the device
   * @attr: completion queue attributes
   * @context: user context
   * @udata: user data
   *
   * @return: ib_cq completion queue pointer on success,
   *          otherwise returns negative errno.
   */
  struct ib_cq *pvrdma_create_cq(struct ib_device *ibdev,
  			       const struct ib_cq_init_attr *attr,
  			       struct ib_ucontext *context,
  			       struct ib_udata *udata)
  {
  	int entries = attr->cqe;
  	struct pvrdma_dev *dev = to_vdev(ibdev);
  	struct pvrdma_cq *cq;
  	int ret;
  	int npages;
  	unsigned long flags;
  	union pvrdma_cmd_req req;
  	union pvrdma_cmd_resp rsp;
  	struct pvrdma_cmd_create_cq *cmd = &req.create_cq;
  	struct pvrdma_cmd_create_cq_resp *resp = &rsp.create_cq_resp;
  	struct pvrdma_create_cq_resp cq_resp = {0};
  	struct pvrdma_create_cq ucmd;
  
  	BUILD_BUG_ON(sizeof(struct pvrdma_cqe) != 64);
  
  	entries = roundup_pow_of_two(entries);
  	if (entries < 1 || entries > dev->dsr->caps.max_cqe)
  		return ERR_PTR(-EINVAL);
  
  	if (!atomic_add_unless(&dev->num_cqs, 1, dev->dsr->caps.max_cq))
  		return ERR_PTR(-ENOMEM);
  
  	cq = kzalloc(sizeof(*cq), GFP_KERNEL);
  	if (!cq) {
  		atomic_dec(&dev->num_cqs);
  		return ERR_PTR(-ENOMEM);
  	}
  
  	cq->ibcq.cqe = entries;
  	cq->is_kernel = !context;
  
  	if (!cq->is_kernel) {
  		if (ib_copy_from_udata(&ucmd, udata, sizeof(ucmd))) {
  			ret = -EFAULT;
  			goto err_cq;
  		}
  
  		cq->umem = ib_umem_get(context, ucmd.buf_addr, ucmd.buf_size,
  				       IB_ACCESS_LOCAL_WRITE, 1);
  		if (IS_ERR(cq->umem)) {
  			ret = PTR_ERR(cq->umem);
  			goto err_cq;
  		}
  
  		npages = ib_umem_page_count(cq->umem);
  	} else {
  		/* One extra page for shared ring state */
  		npages = 1 + (entries * sizeof(struct pvrdma_cqe) +
  			      PAGE_SIZE - 1) / PAGE_SIZE;
  
  		/* Skip header page. */
  		cq->offset = PAGE_SIZE;
  	}
  
  	if (npages < 0 || npages > PVRDMA_PAGE_DIR_MAX_PAGES) {
  		dev_warn(&dev->pdev->dev,
  			 "overflow pages in completion queue\n");
  		ret = -EINVAL;
  		goto err_umem;
  	}
  
  	ret = pvrdma_page_dir_init(dev, &cq->pdir, npages, cq->is_kernel);
  	if (ret) {
  		dev_warn(&dev->pdev->dev,
  			 "could not allocate page directory\n");
  		goto err_umem;
  	}
  
  	/* Ring state is always the first page. Set in library for user cq. */
  	if (cq->is_kernel)
  		cq->ring_state = cq->pdir.pages[0];
  	else
  		pvrdma_page_dir_insert_umem(&cq->pdir, cq->umem, 0);
  
  	refcount_set(&cq->refcnt, 1);
  	init_completion(&cq->free);
  	spin_lock_init(&cq->cq_lock);
  
  	memset(cmd, 0, sizeof(*cmd));
  	cmd->hdr.cmd = PVRDMA_CMD_CREATE_CQ;
  	cmd->nchunks = npages;
  	cmd->ctx_handle = (context) ?
  		(u64)to_vucontext(context)->ctx_handle : 0;
  	cmd->cqe = entries;
  	cmd->pdir_dma = cq->pdir.dir_dma;
  	ret = pvrdma_cmd_post(dev, &req, &rsp, PVRDMA_CMD_CREATE_CQ_RESP);
  	if (ret < 0) {
  		dev_warn(&dev->pdev->dev,
  			 "could not create completion queue, error: %d\n", ret);
  		goto err_page_dir;
  	}
  
  	cq->ibcq.cqe = resp->cqe;
  	cq->cq_handle = resp->cq_handle;
  	cq_resp.cqn = resp->cq_handle;
  	spin_lock_irqsave(&dev->cq_tbl_lock, flags);
  	dev->cq_tbl[cq->cq_handle % dev->dsr->caps.max_cq] = cq;
  	spin_unlock_irqrestore(&dev->cq_tbl_lock, flags);
  
  	if (!cq->is_kernel) {
  		cq->uar = &(to_vucontext(context)->uar);
  
  		/* Copy udata back. */
  		if (ib_copy_to_udata(udata, &cq_resp, sizeof(cq_resp))) {
  			dev_warn(&dev->pdev->dev,
  				 "failed to copy back udata\n");
  			pvrdma_destroy_cq(&cq->ibcq);
  			return ERR_PTR(-EINVAL);
  		}
  	}
  
  	return &cq->ibcq;
  
  err_page_dir:
  	pvrdma_page_dir_cleanup(dev, &cq->pdir);
  err_umem:
  	if (!cq->is_kernel)
  		ib_umem_release(cq->umem);
  err_cq:
  	atomic_dec(&dev->num_cqs);
  	kfree(cq);
  
  	return ERR_PTR(ret);
  }
  
  static void pvrdma_free_cq(struct pvrdma_dev *dev, struct pvrdma_cq *cq)
  {
  	if (refcount_dec_and_test(&cq->refcnt))
  		complete(&cq->free);
  	wait_for_completion(&cq->free);
  
  	if (!cq->is_kernel)
  		ib_umem_release(cq->umem);
  
  	pvrdma_page_dir_cleanup(dev, &cq->pdir);
  	kfree(cq);
  }
  
  /**
   * pvrdma_destroy_cq - destroy completion queue
   * @cq: the completion queue to destroy.
   *
   * @return: 0 for success.
   */
  int pvrdma_destroy_cq(struct ib_cq *cq)
  {
  	struct pvrdma_cq *vcq = to_vcq(cq);
  	union pvrdma_cmd_req req;
  	struct pvrdma_cmd_destroy_cq *cmd = &req.destroy_cq;
  	struct pvrdma_dev *dev = to_vdev(cq->device);
  	unsigned long flags;
  	int ret;
  
  	memset(cmd, 0, sizeof(*cmd));
  	cmd->hdr.cmd = PVRDMA_CMD_DESTROY_CQ;
  	cmd->cq_handle = vcq->cq_handle;
  
  	ret = pvrdma_cmd_post(dev, &req, NULL, 0);
  	if (ret < 0)
  		dev_warn(&dev->pdev->dev,
  			 "could not destroy completion queue, error: %d\n",
  			 ret);
  
  	/* free cq's resources */
  	spin_lock_irqsave(&dev->cq_tbl_lock, flags);
  	dev->cq_tbl[vcq->cq_handle] = NULL;
  	spin_unlock_irqrestore(&dev->cq_tbl_lock, flags);
  
  	pvrdma_free_cq(dev, vcq);
  	atomic_dec(&dev->num_cqs);
  
  	return ret;
  }
  
  static inline struct pvrdma_cqe *get_cqe(struct pvrdma_cq *cq, int i)
  {
  	return (struct pvrdma_cqe *)pvrdma_page_dir_get_ptr(
  					&cq->pdir,
  					cq->offset +
  					sizeof(struct pvrdma_cqe) * i);
  }
  
  void _pvrdma_flush_cqe(struct pvrdma_qp *qp, struct pvrdma_cq *cq)
  {
  	unsigned int head;
  	int has_data;
  
  	if (!cq->is_kernel)
  		return;
  
  	/* Lock held */
  	has_data = pvrdma_idx_ring_has_data(&cq->ring_state->rx,
  					    cq->ibcq.cqe, &head);
  	if (unlikely(has_data > 0)) {
  		int items;
  		int curr;
  		int tail = pvrdma_idx(&cq->ring_state->rx.prod_tail,
  				      cq->ibcq.cqe);
  		struct pvrdma_cqe *cqe;
  		struct pvrdma_cqe *curr_cqe;
  
  		items = (tail > head) ? (tail - head) :
  			(cq->ibcq.cqe - head + tail);
  		curr = --tail;
  		while (items-- > 0) {
  			if (curr < 0)
  				curr = cq->ibcq.cqe - 1;
  			if (tail < 0)
  				tail = cq->ibcq.cqe - 1;
  			curr_cqe = get_cqe(cq, curr);
  			if ((curr_cqe->qp & 0xFFFF) != qp->qp_handle) {
  				if (curr != tail) {
  					cqe = get_cqe(cq, tail);
  					*cqe = *curr_cqe;
  				}
  				tail--;
  			} else {
  				pvrdma_idx_ring_inc(
  					&cq->ring_state->rx.cons_head,
  					cq->ibcq.cqe);
  			}
  			curr--;
  		}
  	}
  }
  
  static int pvrdma_poll_one(struct pvrdma_cq *cq, struct pvrdma_qp **cur_qp,
  			   struct ib_wc *wc)
  {
  	struct pvrdma_dev *dev = to_vdev(cq->ibcq.device);
  	int has_data;
  	unsigned int head;
  	bool tried = false;
  	struct pvrdma_cqe *cqe;
  
  retry:
  	has_data = pvrdma_idx_ring_has_data(&cq->ring_state->rx,
  					    cq->ibcq.cqe, &head);
  	if (has_data == 0) {
  		if (tried)
  			return -EAGAIN;
  
  		pvrdma_write_uar_cq(dev, cq->cq_handle | PVRDMA_UAR_CQ_POLL);
  
  		tried = true;
  		goto retry;
  	} else if (has_data == PVRDMA_INVALID_IDX) {
  		dev_err(&dev->pdev->dev, "CQ ring state invalid\n");
  		return -EAGAIN;
  	}
  
  	cqe = get_cqe(cq, head);
  
  	/* Ensure cqe is valid. */
  	rmb();
  	if (dev->qp_tbl[cqe->qp & 0xffff])
  		*cur_qp = (struct pvrdma_qp *)dev->qp_tbl[cqe->qp & 0xffff];
  	else
  		return -EAGAIN;
  
  	wc->opcode = pvrdma_wc_opcode_to_ib(cqe->opcode);
  	wc->status = pvrdma_wc_status_to_ib(cqe->status);
  	wc->wr_id = cqe->wr_id;
  	wc->qp = &(*cur_qp)->ibqp;
  	wc->byte_len = cqe->byte_len;
  	wc->ex.imm_data = cqe->imm_data;
  	wc->src_qp = cqe->src_qp;
  	wc->wc_flags = pvrdma_wc_flags_to_ib(cqe->wc_flags);
  	wc->pkey_index = cqe->pkey_index;
  	wc->slid = cqe->slid;
  	wc->sl = cqe->sl;
  	wc->dlid_path_bits = cqe->dlid_path_bits;
  	wc->port_num = cqe->port_num;
  	wc->vendor_err = cqe->vendor_err;
  	wc->network_hdr_type = cqe->network_hdr_type;
  
  	/* Update shared ring state */
  	pvrdma_idx_ring_inc(&cq->ring_state->rx.cons_head, cq->ibcq.cqe);
  
  	return 0;
  }
  
  /**
   * pvrdma_poll_cq - poll for work completion queue entries
   * @ibcq: completion queue
   * @num_entries: the maximum number of entries
   * @entry: pointer to work completion array
   *
   * @return: number of polled completion entries
   */
  int pvrdma_poll_cq(struct ib_cq *ibcq, int num_entries, struct ib_wc *wc)
  {
  	struct pvrdma_cq *cq = to_vcq(ibcq);
  	struct pvrdma_qp *cur_qp = NULL;
  	unsigned long flags;
  	int npolled;
  
  	if (num_entries < 1 || wc == NULL)
  		return 0;
  
  	spin_lock_irqsave(&cq->cq_lock, flags);
  	for (npolled = 0; npolled < num_entries; ++npolled) {
  		if (pvrdma_poll_one(cq, &cur_qp, wc + npolled))
  			break;
  	}
  
  	spin_unlock_irqrestore(&cq->cq_lock, flags);
  
  	/* Ensure we do not return errors from poll_cq */
  	return npolled;
  }
  