/*
 * Copyright (c) 2004, 2005, 2006 Voltaire, Inc. All rights reserved.
 * Copyright (c) 2013-2014 Mellanox Technologies. All rights reserved.
 *
 * This software is available to you under a choice of one of two
 * licenses.  You may choose to be licensed under the terms of the GNU
 * General Public License (GPL) Version 2, available from the file
 * COPYING in the main directory of this source tree, or the
 * OpenIB.org BSD license below:
 *
 *     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.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/mm.h>
#include <linux/highmem.h>
#include <linux/scatterlist.h>

#include "iscsi_iser.h"

void iser_reg_comp(struct ib_cq *cq, struct ib_wc *wc)
{
	iser_err_comp(wc, "memreg");
}

static struct iser_fr_desc *
iser_reg_desc_get_fr(struct ib_conn *ib_conn)
{
	struct iser_fr_pool *fr_pool = &ib_conn->fr_pool;
	struct iser_fr_desc *desc;
	unsigned long flags;

	spin_lock_irqsave(&fr_pool->lock, flags);
	desc = list_first_entry(&fr_pool->list,
				struct iser_fr_desc, list);
	list_del(&desc->list);
	spin_unlock_irqrestore(&fr_pool->lock, flags);

	return desc;
}

static void
iser_reg_desc_put_fr(struct ib_conn *ib_conn,
		     struct iser_fr_desc *desc)
{
	struct iser_fr_pool *fr_pool = &ib_conn->fr_pool;
	unsigned long flags;

	spin_lock_irqsave(&fr_pool->lock, flags);
	list_add(&desc->list, &fr_pool->list);
	spin_unlock_irqrestore(&fr_pool->lock, flags);
}

int iser_dma_map_task_data(struct iscsi_iser_task *iser_task,
			    struct iser_data_buf *data,
			    enum iser_data_dir iser_dir,
			    enum dma_data_direction dma_dir)
{
	struct ib_device *dev;

	iser_task->dir[iser_dir] = 1;
	dev = iser_task->iser_conn->ib_conn.device->ib_device;

	data->dma_nents = ib_dma_map_sg(dev, data->sg, data->size, dma_dir);
	if (unlikely(data->dma_nents == 0)) {
		iser_err("dma_map_sg failed!!!\n");
		return -EINVAL;
	}
	return 0;
}

void iser_dma_unmap_task_data(struct iscsi_iser_task *iser_task,
			      struct iser_data_buf *data,
			      enum dma_data_direction dir)
{
	struct ib_device *dev;

	dev = iser_task->iser_conn->ib_conn.device->ib_device;
	ib_dma_unmap_sg(dev, data->sg, data->size, dir);
}

static int
iser_reg_dma(struct iser_device *device, struct iser_data_buf *mem,
	     struct iser_mem_reg *reg)
{
	struct scatterlist *sg = mem->sg;

	reg->sge.lkey = device->pd->local_dma_lkey;
	/*
	 * FIXME: rework the registration code path to differentiate
	 * rkey/lkey use cases
	 */

	if (device->pd->flags & IB_PD_UNSAFE_GLOBAL_RKEY)
		reg->rkey = device->pd->unsafe_global_rkey;
	else
		reg->rkey = 0;
	reg->sge.addr = sg_dma_address(&sg[0]);
	reg->sge.length = sg_dma_len(&sg[0]);

	iser_dbg("Single DMA entry: lkey=0x%x, rkey=0x%x, addr=0x%llx,"
		 " length=0x%x\n", reg->sge.lkey, reg->rkey,
		 reg->sge.addr, reg->sge.length);

	return 0;
}

void iser_unreg_mem_fastreg(struct iscsi_iser_task *iser_task,
			    enum iser_data_dir cmd_dir)
{
	struct iser_mem_reg *reg = &iser_task->rdma_reg[cmd_dir];
	struct iser_fr_desc *desc;
	struct ib_mr_status mr_status;

	desc = reg->mem_h;
	if (!desc)
		return;

	/*
	 * The signature MR cannot be invalidated and reused without checking.
	 * libiscsi calls the check_protection transport handler only if
	 * SCSI-Response is received. And the signature MR is not checked if
	 * the task is completed for some other reason like a timeout or error
	 * handling. That's why we must check the signature MR here before
	 * putting it to the free pool.
	 */
	if (unlikely(desc->sig_protected)) {
		desc->sig_protected = false;
		ib_check_mr_status(desc->rsc.sig_mr, IB_MR_CHECK_SIG_STATUS,
				   &mr_status);
	}
	iser_reg_desc_put_fr(&iser_task->iser_conn->ib_conn, reg->mem_h);
	reg->mem_h = NULL;
}

static void
iser_set_dif_domain(struct scsi_cmnd *sc, struct ib_sig_domain *domain)
{
	domain->sig_type = IB_SIG_TYPE_T10_DIF;
	domain->sig.dif.pi_interval = scsi_prot_interval(sc);
	domain->sig.dif.ref_tag = t10_pi_ref_tag(scsi_cmd_to_rq(sc));
	/*
	 * At the moment we hard code those, but in the future
	 * we will take them from sc.
	 */
	domain->sig.dif.apptag_check_mask = 0xffff;
	domain->sig.dif.app_escape = true;
	domain->sig.dif.ref_escape = true;
	if (sc->prot_flags & SCSI_PROT_REF_INCREMENT)
		domain->sig.dif.ref_remap = true;
}

static int
iser_set_sig_attrs(struct scsi_cmnd *sc, struct ib_sig_attrs *sig_attrs)
{
	switch (scsi_get_prot_op(sc)) {
	case SCSI_PROT_WRITE_INSERT:
	case SCSI_PROT_READ_STRIP:
		sig_attrs->mem.sig_type = IB_SIG_TYPE_NONE;
		iser_set_dif_domain(sc, &sig_attrs->wire);
		sig_attrs->wire.sig.dif.bg_type = IB_T10DIF_CRC;
		break;
	case SCSI_PROT_READ_INSERT:
	case SCSI_PROT_WRITE_STRIP:
		sig_attrs->wire.sig_type = IB_SIG_TYPE_NONE;
		iser_set_dif_domain(sc, &sig_attrs->mem);
		sig_attrs->mem.sig.dif.bg_type = sc->prot_flags & SCSI_PROT_IP_CHECKSUM ?
						IB_T10DIF_CSUM : IB_T10DIF_CRC;
		break;
	case SCSI_PROT_READ_PASS:
	case SCSI_PROT_WRITE_PASS:
		iser_set_dif_domain(sc, &sig_attrs->wire);
		sig_attrs->wire.sig.dif.bg_type = IB_T10DIF_CRC;
		iser_set_dif_domain(sc, &sig_attrs->mem);
		sig_attrs->mem.sig.dif.bg_type = sc->prot_flags & SCSI_PROT_IP_CHECKSUM ?
						IB_T10DIF_CSUM : IB_T10DIF_CRC;
		break;
	default:
		iser_err("Unsupported PI operation %d\n",
			 scsi_get_prot_op(sc));
		return -EINVAL;
	}

	return 0;
}

static inline void
iser_set_prot_checks(struct scsi_cmnd *sc, u8 *mask)
{
	*mask = 0;
	if (sc->prot_flags & SCSI_PROT_REF_CHECK)
		*mask |= IB_SIG_CHECK_REFTAG;
	if (sc->prot_flags & SCSI_PROT_GUARD_CHECK)
		*mask |= IB_SIG_CHECK_GUARD;
}

static inline void
iser_inv_rkey(struct ib_send_wr *inv_wr,
	      struct ib_mr *mr,
	      struct ib_cqe *cqe,
	      struct ib_send_wr *next_wr)
{
	inv_wr->opcode = IB_WR_LOCAL_INV;
	inv_wr->wr_cqe = cqe;
	inv_wr->ex.invalidate_rkey = mr->rkey;
	inv_wr->send_flags = 0;
	inv_wr->num_sge = 0;
	inv_wr->next = next_wr;
}

static int
iser_reg_sig_mr(struct iscsi_iser_task *iser_task,
		struct iser_data_buf *mem,
		struct iser_data_buf *sig_mem,
		struct iser_reg_resources *rsc,
		struct iser_mem_reg *sig_reg)
{
	struct iser_tx_desc *tx_desc = &iser_task->desc;
	struct ib_cqe *cqe = &iser_task->iser_conn->ib_conn.reg_cqe;
	struct ib_mr *mr = rsc->sig_mr;
	struct ib_sig_attrs *sig_attrs = mr->sig_attrs;
	struct ib_reg_wr *wr = &tx_desc->reg_wr;
	int ret;

	memset(sig_attrs, 0, sizeof(*sig_attrs));
	ret = iser_set_sig_attrs(iser_task->sc, sig_attrs);
	if (ret)
		goto err;

	iser_set_prot_checks(iser_task->sc, &sig_attrs->check_mask);

	if (rsc->sig_mr->need_inval)
		iser_inv_rkey(&tx_desc->inv_wr, mr, cqe, &wr->wr);

	ib_update_fast_reg_key(mr, ib_inc_rkey(mr->rkey));

	ret = ib_map_mr_sg_pi(mr, mem->sg, mem->dma_nents, NULL,
			      sig_mem->sg, sig_mem->dma_nents, NULL, SZ_4K);
	if (unlikely(ret)) {
		iser_err("failed to map PI sg (%d)\n",
			 mem->dma_nents + sig_mem->dma_nents);
		goto err;
	}

	memset(wr, 0, sizeof(*wr));
	wr->wr.next = &tx_desc->send_wr;
	wr->wr.opcode = IB_WR_REG_MR_INTEGRITY;
	wr->wr.wr_cqe = cqe;
	wr->wr.num_sge = 0;
	wr->wr.send_flags = 0;
	wr->mr = mr;
	wr->key = mr->rkey;
	wr->access = IB_ACCESS_LOCAL_WRITE |
		     IB_ACCESS_REMOTE_READ |
		     IB_ACCESS_REMOTE_WRITE;
	rsc->sig_mr->need_inval = true;

	sig_reg->sge.lkey = mr->lkey;
	sig_reg->rkey = mr->rkey;
	sig_reg->sge.addr = mr->iova;
	sig_reg->sge.length = mr->length;

	iser_dbg("lkey=0x%x rkey=0x%x addr=0x%llx length=%u\n",
		 sig_reg->sge.lkey, sig_reg->rkey, sig_reg->sge.addr,
		 sig_reg->sge.length);
err:
	return ret;
}

static int iser_fast_reg_mr(struct iscsi_iser_task *iser_task,
			    struct iser_data_buf *mem,
			    struct iser_reg_resources *rsc,
			    struct iser_mem_reg *reg)
{
	struct iser_tx_desc *tx_desc = &iser_task->desc;
	struct ib_cqe *cqe = &iser_task->iser_conn->ib_conn.reg_cqe;
	struct ib_mr *mr = rsc->mr;
	struct ib_reg_wr *wr = &tx_desc->reg_wr;
	int n;

	if (rsc->mr->need_inval)
		iser_inv_rkey(&tx_desc->inv_wr, mr, cqe, &wr->wr);

	ib_update_fast_reg_key(mr, ib_inc_rkey(mr->rkey));

	n = ib_map_mr_sg(mr, mem->sg, mem->dma_nents, NULL, SZ_4K);
	if (unlikely(n != mem->dma_nents)) {
		iser_err("failed to map sg (%d/%d)\n",
			 n, mem->dma_nents);
		return n < 0 ? n : -EINVAL;
	}

	wr->wr.next = &tx_desc->send_wr;
	wr->wr.opcode = IB_WR_REG_MR;
	wr->wr.wr_cqe = cqe;
	wr->wr.send_flags = 0;
	wr->wr.num_sge = 0;
	wr->mr = mr;
	wr->key = mr->rkey;
	wr->access = IB_ACCESS_LOCAL_WRITE  |
		     IB_ACCESS_REMOTE_WRITE |
		     IB_ACCESS_REMOTE_READ;

	rsc->mr->need_inval = true;

	reg->sge.lkey = mr->lkey;
	reg->rkey = mr->rkey;
	reg->sge.addr = mr->iova;
	reg->sge.length = mr->length;

	iser_dbg("lkey=0x%x rkey=0x%x addr=0x%llx length=0x%x\n",
		 reg->sge.lkey, reg->rkey, reg->sge.addr, reg->sge.length);

	return 0;
}

static int
iser_reg_data_sg(struct iscsi_iser_task *task,
		 struct iser_data_buf *mem,
		 struct iser_fr_desc *desc,
		 bool use_dma_key,
		 struct iser_mem_reg *reg)
{
	struct iser_device *device = task->iser_conn->ib_conn.device;

	if (use_dma_key)
		return iser_reg_dma(device, mem, reg);

	return iser_fast_reg_mr(task, mem, &desc->rsc, reg);
}

int iser_reg_mem_fastreg(struct iscsi_iser_task *task,
			 enum iser_data_dir dir,
			 bool all_imm)
{
	struct ib_conn *ib_conn = &task->iser_conn->ib_conn;
	struct iser_data_buf *mem = &task->data[dir];
	struct iser_mem_reg *reg = &task->rdma_reg[dir];
	struct iser_fr_desc *desc = NULL;
	bool use_dma_key;
	int err;

	use_dma_key = mem->dma_nents == 1 && (all_imm || !iser_always_reg) &&
		      scsi_get_prot_op(task->sc) == SCSI_PROT_NORMAL;

	if (!use_dma_key) {
		desc = iser_reg_desc_get_fr(ib_conn);
		reg->mem_h = desc;
	}

	if (scsi_get_prot_op(task->sc) == SCSI_PROT_NORMAL) {
		err = iser_reg_data_sg(task, mem, desc, use_dma_key, reg);
		if (unlikely(err))
			goto err_reg;
	} else {
		err = iser_reg_sig_mr(task, mem, &task->prot[dir],
				      &desc->rsc, reg);
		if (unlikely(err))
			goto err_reg;

		desc->sig_protected = true;
	}

	return 0;

err_reg:
	if (desc)
		iser_reg_desc_put_fr(ib_conn, desc);

	return err;
}