/*
 * 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/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,
                           enum iser_data_dir iser_dir,
                           enum dma_data_direction dma_dir)
{
        struct iser_data_buf *data = &iser_task->data[iser_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;
        }

        if (scsi_prot_sg_count(iser_task->sc)) {
                struct iser_data_buf *pdata = &iser_task->prot[iser_dir];

                pdata->dma_nents = ib_dma_map_sg(dev, pdata->sg, pdata->size, dma_dir);
                if (unlikely(pdata->dma_nents == 0)) {
                        iser_err("protection dma_map_sg failed!!!\n");
                        goto out_unmap;
                }
        }

        return 0;

out_unmap:
        ib_dma_unmap_sg(dev, data->sg, data->size, dma_dir);
        return -EINVAL;
}


void iser_dma_unmap_task_data(struct iscsi_iser_task *iser_task,
                              enum iser_data_dir iser_dir,
                              enum dma_data_direction dma_dir)
{
        struct iser_data_buf *data = &iser_task->data[iser_dir];
        struct ib_device *dev;

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

        if (scsi_prot_sg_count(iser_task->sc)) {
                struct iser_data_buf *pdata = &iser_task->prot[iser_dir];

                ib_dma_unmap_sg(dev, pdata->sg, pdata->size, dma_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->desc;
        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->desc);
        reg->desc = 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;
}

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_device *device = ib_conn->device;
        struct iser_data_buf *mem = &task->data[dir];
        struct iser_mem_reg *reg = &task->rdma_reg[dir];
        struct iser_fr_desc *desc;
        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)
                return iser_reg_dma(device, mem, reg);

        desc = iser_reg_desc_get_fr(ib_conn);
        if (scsi_get_prot_op(task->sc) == SCSI_PROT_NORMAL) {
                err = iser_fast_reg_mr(task, mem, &desc->rsc, 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;
        }

        reg->desc = desc;

        return 0;

err_reg:
        iser_reg_desc_put_fr(ib_conn, desc);

        return err;
}