/*
 * Copyright (c) 2004, 2005, 2006 Voltaire, Inc. 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/scatterlist.h>
#include <linux/kfifo.h>
#include <scsi/scsi_cmnd.h>
#include <scsi/scsi_host.h>

#include "iscsi_iser.h"

/* Register user buffer memory and initialize passive rdma
 *  dto descriptor. Total data size is stored in
 *  iser_task->data[ISER_DIR_IN].data_len
 */
static int iser_prepare_read_cmd(struct iscsi_task *task,
                                 unsigned int edtl)

{
        struct iscsi_iser_task *iser_task = task->dd_data;
        struct iser_regd_buf *regd_buf;
        int err;
        struct iser_hdr *hdr = &iser_task->desc.iser_header;
        struct iser_data_buf *buf_in = &iser_task->data[ISER_DIR_IN];

        err = iser_dma_map_task_data(iser_task,
                                     buf_in,
                                     ISER_DIR_IN,
                                     DMA_FROM_DEVICE);
        if (err)
                return err;

        if (edtl > iser_task->data[ISER_DIR_IN].data_len) {
                iser_err("Total data length: %ld, less than EDTL: "
                         "%d, in READ cmd BHS itt: %d, conn: 0x%p\n",
                         iser_task->data[ISER_DIR_IN].data_len, edtl,
                         task->itt, iser_task->iser_conn);
                return -EINVAL;
        }

        err = iser_reg_rdma_mem(iser_task,ISER_DIR_IN);
        if (err) {
                iser_err("Failed to set up Data-IN RDMA\n");
                return err;
        }
        regd_buf = &iser_task->rdma_regd[ISER_DIR_IN];

        hdr->flags    |= ISER_RSV;
        hdr->read_stag = cpu_to_be32(regd_buf->reg.rkey);
        hdr->read_va   = cpu_to_be64(regd_buf->reg.va);

        iser_dbg("Cmd itt:%d READ tags RKEY:%#.4X VA:%#llX\n",
                 task->itt, regd_buf->reg.rkey,
                 (unsigned long long)regd_buf->reg.va);

        return 0;
}

/* Register user buffer memory and initialize passive rdma
 *  dto descriptor. Total data size is stored in
 *  task->data[ISER_DIR_OUT].data_len
 */
static int
iser_prepare_write_cmd(struct iscsi_task *task,
                       unsigned int imm_sz,
                       unsigned int unsol_sz,
                       unsigned int edtl)
{
        struct iscsi_iser_task *iser_task = task->dd_data;
        struct iser_regd_buf *regd_buf;
        int err;
        struct iser_hdr *hdr = &iser_task->desc.iser_header;
        struct iser_data_buf *buf_out = &iser_task->data[ISER_DIR_OUT];
        struct ib_sge *tx_dsg = &iser_task->desc.tx_sg[1];

        err = iser_dma_map_task_data(iser_task,
                                     buf_out,
                                     ISER_DIR_OUT,
                                     DMA_TO_DEVICE);
        if (err)
                return err;

        if (edtl > iser_task->data[ISER_DIR_OUT].data_len) {
                iser_err("Total data length: %ld, less than EDTL: %d, "
                         "in WRITE cmd BHS itt: %d, conn: 0x%p\n",
                         iser_task->data[ISER_DIR_OUT].data_len,
                         edtl, task->itt, task->conn);
                return -EINVAL;
        }

        err = iser_reg_rdma_mem(iser_task,ISER_DIR_OUT);
        if (err != 0) {
                iser_err("Failed to register write cmd RDMA mem\n");
                return err;
        }

        regd_buf = &iser_task->rdma_regd[ISER_DIR_OUT];

        if (unsol_sz < edtl) {
                hdr->flags     |= ISER_WSV;
                hdr->write_stag = cpu_to_be32(regd_buf->reg.rkey);
                hdr->write_va   = cpu_to_be64(regd_buf->reg.va + unsol_sz);

                iser_dbg("Cmd itt:%d, WRITE tags, RKEY:%#.4X "
                         "VA:%#llX + unsol:%d\n",
                         task->itt, regd_buf->reg.rkey,
                         (unsigned long long)regd_buf->reg.va, unsol_sz);
        }

        if (imm_sz > 0) {
                iser_dbg("Cmd itt:%d, WRITE, adding imm.data sz: %d\n",
                         task->itt, imm_sz);
                tx_dsg->addr   = regd_buf->reg.va;
                tx_dsg->length = imm_sz;
                tx_dsg->lkey   = regd_buf->reg.lkey;
                iser_task->desc.num_sge = 2;
        }

        return 0;
}

/* creates a new tx descriptor and adds header regd buffer */
static void iser_create_send_desc(struct iser_conn      *ib_conn,
                                  struct iser_tx_desc   *tx_desc)
{
        struct iser_device *device = ib_conn->device;

        ib_dma_sync_single_for_cpu(device->ib_device,
                tx_desc->dma_addr, ISER_HEADERS_LEN, DMA_TO_DEVICE);

        memset(&tx_desc->iser_header, 0, sizeof(struct iser_hdr));
        tx_desc->iser_header.flags = ISER_VER;

        tx_desc->num_sge = 1;

        if (tx_desc->tx_sg[0].lkey != device->mr->lkey) {
                tx_desc->tx_sg[0].lkey = device->mr->lkey;
                iser_dbg("sdesc %p lkey mismatch, fixing\n", tx_desc);
        }
}


int iser_alloc_rx_descriptors(struct iser_conn *ib_conn)
{
        int i, j;
        u64 dma_addr;
        struct iser_rx_desc *rx_desc;
        struct ib_sge       *rx_sg;
        struct iser_device  *device = ib_conn->device;

        ib_conn->rx_descs = kmalloc(ISER_QP_MAX_RECV_DTOS *
                                sizeof(struct iser_rx_desc), GFP_KERNEL);
        if (!ib_conn->rx_descs)
                goto rx_desc_alloc_fail;

        rx_desc = ib_conn->rx_descs;

        for (i = 0; i < ISER_QP_MAX_RECV_DTOS; i++, rx_desc++)  {
                dma_addr = ib_dma_map_single(device->ib_device, (void *)rx_desc,
                                        ISER_RX_PAYLOAD_SIZE, DMA_FROM_DEVICE);
                if (ib_dma_mapping_error(device->ib_device, dma_addr))
                        goto rx_desc_dma_map_failed;

                rx_desc->dma_addr = dma_addr;

                rx_sg = &rx_desc->rx_sg;
                rx_sg->addr   = rx_desc->dma_addr;
                rx_sg->length = ISER_RX_PAYLOAD_SIZE;
                rx_sg->lkey   = device->mr->lkey;
        }

        ib_conn->rx_desc_head = 0;
        return 0;

rx_desc_dma_map_failed:
        rx_desc = ib_conn->rx_descs;
        for (j = 0; j < i; j++, rx_desc++)
                ib_dma_unmap_single(device->ib_device, rx_desc->dma_addr,
                        ISER_RX_PAYLOAD_SIZE, DMA_FROM_DEVICE);
        kfree(ib_conn->rx_descs);
        ib_conn->rx_descs = NULL;
rx_desc_alloc_fail:
        iser_err("failed allocating rx descriptors / data buffers\n");
        return -ENOMEM;
}

void iser_free_rx_descriptors(struct iser_conn *ib_conn)
{
        int i;
        struct iser_rx_desc *rx_desc;
        struct iser_device *device = ib_conn->device;

        if (!ib_conn->rx_descs)
                return;

        rx_desc = ib_conn->rx_descs;
        for (i = 0; i < ISER_QP_MAX_RECV_DTOS; i++, rx_desc++)
                ib_dma_unmap_single(device->ib_device, rx_desc->dma_addr,
                        ISER_RX_PAYLOAD_SIZE, DMA_FROM_DEVICE);
        kfree(ib_conn->rx_descs);
}

static int iser_post_rx_bufs(struct iscsi_conn *conn, struct iscsi_hdr *req)
{
        struct iscsi_iser_conn *iser_conn = conn->dd_data;

        iser_dbg("req op %x flags %x\n", req->opcode, req->flags);
        /* check if this is the last login - going to full feature phase */
        if ((req->flags & ISCSI_FULL_FEATURE_PHASE) != ISCSI_FULL_FEATURE_PHASE)
                return 0;

        /*
         * Check that there is one posted recv buffer (for the last login
         * response) and no posted send buffers left - they must have been
         * consumed during previous login phases.
         */
        WARN_ON(iser_conn->ib_conn->post_recv_buf_count != 1);
        WARN_ON(atomic_read(&iser_conn->ib_conn->post_send_buf_count) != 0);

        iser_dbg("Initially post: %d\n", ISER_MIN_POSTED_RX);
        /* Initial post receive buffers */
        if (iser_post_recvm(iser_conn->ib_conn, ISER_MIN_POSTED_RX))
                return -ENOMEM;

        return 0;
}

/**
 * iser_send_command - send command PDU
 */
int iser_send_command(struct iscsi_conn *conn,
                      struct iscsi_task *task)
{
        struct iscsi_iser_conn *iser_conn = conn->dd_data;
        struct iscsi_iser_task *iser_task = task->dd_data;
        unsigned long edtl;
        int err;
        struct iser_data_buf *data_buf;
        struct iscsi_scsi_req *hdr = (struct iscsi_scsi_req *)task->hdr;
        struct scsi_cmnd *sc  =  task->sc;
        struct iser_tx_desc *tx_desc = &iser_task->desc;

        edtl = ntohl(hdr->data_length);

        /* build the tx desc regd header and add it to the tx desc dto */
        tx_desc->type = ISCSI_TX_SCSI_COMMAND;
        iser_create_send_desc(iser_conn->ib_conn, tx_desc);

        if (hdr->flags & ISCSI_FLAG_CMD_READ)
                data_buf = &iser_task->data[ISER_DIR_IN];
        else
                data_buf = &iser_task->data[ISER_DIR_OUT];

        if (scsi_sg_count(sc)) { /* using a scatter list */
                data_buf->buf  = scsi_sglist(sc);
                data_buf->size = scsi_sg_count(sc);
        }

        data_buf->data_len = scsi_bufflen(sc);

        if (hdr->flags & ISCSI_FLAG_CMD_READ) {
                err = iser_prepare_read_cmd(task, edtl);
                if (err)
                        goto send_command_error;
        }
        if (hdr->flags & ISCSI_FLAG_CMD_WRITE) {
                err = iser_prepare_write_cmd(task,
                                             task->imm_count,
                                             task->imm_count +
                                             task->unsol_r2t.data_length,
                                             edtl);
                if (err)
                        goto send_command_error;
        }

        iser_task->status = ISER_TASK_STATUS_STARTED;

        err = iser_post_send(iser_conn->ib_conn, tx_desc);
        if (!err)
                return 0;

send_command_error:
        iser_err("conn %p failed task->itt %d err %d\n",conn, task->itt, err);
        return err;
}

/**
 * iser_send_data_out - send data out PDU
 */
int iser_send_data_out(struct iscsi_conn *conn,
                       struct iscsi_task *task,
                       struct iscsi_data *hdr)
{
        struct iscsi_iser_conn *iser_conn = conn->dd_data;
        struct iscsi_iser_task *iser_task = task->dd_data;
        struct iser_tx_desc *tx_desc = NULL;
        struct iser_regd_buf *regd_buf;
        unsigned long buf_offset;
        unsigned long data_seg_len;
        uint32_t itt;
        int err = 0;
        struct ib_sge *tx_dsg;

        itt = (__force uint32_t)hdr->itt;
        data_seg_len = ntoh24(hdr->dlength);
        buf_offset   = ntohl(hdr->offset);

        iser_dbg("%s itt %d dseg_len %d offset %d\n",
                 __func__,(int)itt,(int)data_seg_len,(int)buf_offset);

        tx_desc = kmem_cache_zalloc(ig.desc_cache, GFP_ATOMIC);
        if (tx_desc == NULL) {
                iser_err("Failed to alloc desc for post dataout\n");
                return -ENOMEM;
        }

        tx_desc->type = ISCSI_TX_DATAOUT;
        tx_desc->iser_header.flags = ISER_VER;
        memcpy(&tx_desc->iscsi_header, hdr, sizeof(struct iscsi_hdr));

        /* build the tx desc */
        iser_initialize_task_headers(task, tx_desc);

        regd_buf = &iser_task->rdma_regd[ISER_DIR_OUT];
        tx_dsg = &tx_desc->tx_sg[1];
        tx_dsg->addr    = regd_buf->reg.va + buf_offset;
        tx_dsg->length  = data_seg_len;
        tx_dsg->lkey    = regd_buf->reg.lkey;
        tx_desc->num_sge = 2;

        if (buf_offset + data_seg_len > iser_task->data[ISER_DIR_OUT].data_len) {
                iser_err("Offset:%ld & DSL:%ld in Data-Out "
                         "inconsistent with total len:%ld, itt:%d\n",
                         buf_offset, data_seg_len,
                         iser_task->data[ISER_DIR_OUT].data_len, itt);
                err = -EINVAL;
                goto send_data_out_error;
        }
        iser_dbg("data-out itt: %d, offset: %ld, sz: %ld\n",
                 itt, buf_offset, data_seg_len);


        err = iser_post_send(iser_conn->ib_conn, tx_desc);
        if (!err)
                return 0;

send_data_out_error:
        kmem_cache_free(ig.desc_cache, tx_desc);
        iser_err("conn %p failed err %d\n",conn, err);
        return err;
}

int iser_send_control(struct iscsi_conn *conn,
                      struct iscsi_task *task)
{
        struct iscsi_iser_conn *iser_conn = conn->dd_data;
        struct iscsi_iser_task *iser_task = task->dd_data;
        struct iser_tx_desc *mdesc = &iser_task->desc;
        unsigned long data_seg_len;
        int err = 0;
        struct iser_device *device;
        struct iser_conn *ib_conn = iser_conn->ib_conn;

        /* build the tx desc regd header and add it to the tx desc dto */
        mdesc->type = ISCSI_TX_CONTROL;
        iser_create_send_desc(iser_conn->ib_conn, mdesc);

        device = iser_conn->ib_conn->device;

        data_seg_len = ntoh24(task->hdr->dlength);

        if (data_seg_len > 0) {
                struct ib_sge *tx_dsg = &mdesc->tx_sg[1];
                if (task != conn->login_task) {
                        iser_err("data present on non login task!!!\n");
                        goto send_control_error;
                }

                ib_dma_sync_single_for_cpu(device->ib_device,
                        ib_conn->login_req_dma, task->data_count,
                        DMA_TO_DEVICE);

                memcpy(iser_conn->ib_conn->login_req_buf, task->data,
                                                        task->data_count);

                ib_dma_sync_single_for_device(device->ib_device,
                        ib_conn->login_req_dma, task->data_count,
                        DMA_TO_DEVICE);

                tx_dsg->addr    = iser_conn->ib_conn->login_req_dma;
                tx_dsg->length  = task->data_count;
                tx_dsg->lkey    = device->mr->lkey;
                mdesc->num_sge = 2;
        }

        if (task == conn->login_task) {
                err = iser_post_recvl(iser_conn->ib_conn);
                if (err)
                        goto send_control_error;
                err = iser_post_rx_bufs(conn, task->hdr);
                if (err)
                        goto send_control_error;
        }

        err = iser_post_send(iser_conn->ib_conn, mdesc);
        if (!err)
                return 0;

send_control_error:
        iser_err("conn %p failed err %d\n",conn, err);
        return err;
}

/**
 * iser_rcv_dto_completion - recv DTO completion
 */
void iser_rcv_completion(struct iser_rx_desc *rx_desc,
                         unsigned long rx_xfer_len,
                         struct iser_conn *ib_conn)
{
        struct iscsi_iser_conn *conn = ib_conn->iser_conn;
        struct iscsi_hdr *hdr;
        u64 rx_dma;
        int rx_buflen, outstanding, count, err;

        /* differentiate between login to all other PDUs */
        if ((char *)rx_desc == ib_conn->login_resp_buf) {
                rx_dma = ib_conn->login_resp_dma;
                rx_buflen = ISER_RX_LOGIN_SIZE;
        } else {
                rx_dma = rx_desc->dma_addr;
                rx_buflen = ISER_RX_PAYLOAD_SIZE;
        }

        ib_dma_sync_single_for_cpu(ib_conn->device->ib_device, rx_dma,
                        rx_buflen, DMA_FROM_DEVICE);

        hdr = &rx_desc->iscsi_header;

        iser_dbg("op 0x%x itt 0x%x dlen %d\n", hdr->opcode,
                        hdr->itt, (int)(rx_xfer_len - ISER_HEADERS_LEN));

        iscsi_iser_recv(conn->iscsi_conn, hdr,
                rx_desc->data, rx_xfer_len - ISER_HEADERS_LEN);

        ib_dma_sync_single_for_device(ib_conn->device->ib_device, rx_dma,
                        rx_buflen, DMA_FROM_DEVICE);

        /* decrementing conn->post_recv_buf_count only --after-- freeing the   *
         * task eliminates the need to worry on tasks which are completed in   *
         * parallel to the execution of iser_conn_term. So the code that waits *
         * for the posted rx bufs refcount to become zero handles everything   */
        conn->ib_conn->post_recv_buf_count--;

        if (rx_dma == ib_conn->login_resp_dma)
                return;

        outstanding = ib_conn->post_recv_buf_count;
        if (outstanding + ISER_MIN_POSTED_RX <= ISER_QP_MAX_RECV_DTOS) {
                count = min(ISER_QP_MAX_RECV_DTOS - outstanding,
                                                ISER_MIN_POSTED_RX);
                err = iser_post_recvm(ib_conn, count);
                if (err)
                        iser_err("posting %d rx bufs err %d\n", count, err);
        }
}

void iser_snd_completion(struct iser_tx_desc *tx_desc,
                        struct iser_conn *ib_conn)
{
        struct iscsi_task *task;
        struct iser_device *device = ib_conn->device;

        if (tx_desc->type == ISCSI_TX_DATAOUT) {
                ib_dma_unmap_single(device->ib_device, tx_desc->dma_addr,
                                        ISER_HEADERS_LEN, DMA_TO_DEVICE);
                kmem_cache_free(ig.desc_cache, tx_desc);
        }

        atomic_dec(&ib_conn->post_send_buf_count);

        if (tx_desc->type == ISCSI_TX_CONTROL) {
                /* this arithmetic is legal by libiscsi dd_data allocation */
                task = (void *) ((long)(void *)tx_desc -
                                  sizeof(struct iscsi_task));
                if (task->hdr->itt == RESERVED_ITT)
                        iscsi_put_task(task);
        }
}

void iser_task_rdma_init(struct iscsi_iser_task *iser_task)

{
        iser_task->status = ISER_TASK_STATUS_INIT;

        iser_task->dir[ISER_DIR_IN] = 0;
        iser_task->dir[ISER_DIR_OUT] = 0;

        iser_task->data[ISER_DIR_IN].data_len  = 0;
        iser_task->data[ISER_DIR_OUT].data_len = 0;

        memset(&iser_task->rdma_regd[ISER_DIR_IN], 0,
               sizeof(struct iser_regd_buf));
        memset(&iser_task->rdma_regd[ISER_DIR_OUT], 0,
               sizeof(struct iser_regd_buf));
}

void iser_task_rdma_finalize(struct iscsi_iser_task *iser_task)
{
        int is_rdma_aligned = 1;
        struct iser_regd_buf *regd;

        /* if we were reading, copy back to unaligned sglist,
         * anyway dma_unmap and free the copy
         */
        if (iser_task->data_copy[ISER_DIR_IN].copy_buf != NULL) {
                is_rdma_aligned = 0;
                iser_finalize_rdma_unaligned_sg(iser_task, ISER_DIR_IN);
        }
        if (iser_task->data_copy[ISER_DIR_OUT].copy_buf != NULL) {
                is_rdma_aligned = 0;
                iser_finalize_rdma_unaligned_sg(iser_task, ISER_DIR_OUT);
        }

        if (iser_task->dir[ISER_DIR_IN]) {
                regd = &iser_task->rdma_regd[ISER_DIR_IN];
                if (regd->reg.is_fmr)
                        iser_unreg_mem(&regd->reg);
        }

        if (iser_task->dir[ISER_DIR_OUT]) {
                regd = &iser_task->rdma_regd[ISER_DIR_OUT];
                if (regd->reg.is_fmr)
                        iser_unreg_mem(&regd->reg);
        }

       /* if the data was unaligned, it was already unmapped and then copied */
       if (is_rdma_aligned)
                iser_dma_unmap_task_data(iser_task);
}