/**********************************************************************
 * Author: Cavium, Inc.
 *
 * Contact: support@cavium.com
 *          Please include "LiquidIO" in the subject.
 *
 * Copyright (c) 2003-2016 Cavium, Inc.
 *
 * This file is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License, Version 2, as
 * published by the Free Software Foundation.
 *
 * This file is distributed in the hope that it will be useful, but
 * AS-IS and WITHOUT ANY WARRANTY; without even the implied warranty
 * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE, TITLE, or
 * NONINFRINGEMENT.  See the GNU General Public License for more
 * details.
 **********************************************************************/
#include <linux/pci.h>
#include <linux/netdevice.h>
#include "liquidio_common.h"
#include "octeon_droq.h"
#include "octeon_iq.h"
#include "response_manager.h"
#include "octeon_device.h"
#include "octeon_main.h"

static void oct_poll_req_completion(struct work_struct *work);

int octeon_setup_response_list(struct octeon_device *oct)
{
        int i, ret = 0;
        struct cavium_wq *cwq;

        for (i = 0; i < MAX_RESPONSE_LISTS; i++) {
                INIT_LIST_HEAD(&oct->response_list[i].head);
                spin_lock_init(&oct->response_list[i].lock);
                atomic_set(&oct->response_list[i].pending_req_count, 0);
        }
        spin_lock_init(&oct->cmd_resp_wqlock);

        oct->dma_comp_wq.wq = alloc_workqueue("dma-comp", WQ_MEM_RECLAIM, 0);
        if (!oct->dma_comp_wq.wq) {
                dev_err(&oct->pci_dev->dev, "failed to create wq thread\n");
                return -ENOMEM;
        }

        cwq = &oct->dma_comp_wq;
        INIT_DELAYED_WORK(&cwq->wk.work, oct_poll_req_completion);
        cwq->wk.ctxptr = oct;
        oct->cmd_resp_state = OCT_DRV_ONLINE;

        return ret;
}

void octeon_delete_response_list(struct octeon_device *oct)
{
        cancel_delayed_work_sync(&oct->dma_comp_wq.wk.work);
        destroy_workqueue(oct->dma_comp_wq.wq);
}

int lio_process_ordered_list(struct octeon_device *octeon_dev,
                             u32 force_quit)
{
        struct octeon_response_list *ordered_sc_list;
        struct octeon_soft_command *sc;
        int request_complete = 0;
        int resp_to_process = MAX_ORD_REQS_TO_PROCESS;
        u32 status;
        u64 status64;

        octeon_free_sc_done_list(octeon_dev);

        ordered_sc_list = &octeon_dev->response_list[OCTEON_ORDERED_SC_LIST];

        do {
                spin_lock_bh(&ordered_sc_list->lock);

                if (list_empty(&ordered_sc_list->head)) {
                        spin_unlock_bh(&ordered_sc_list->lock);
                        return 1;
                }

                sc = list_first_entry(&ordered_sc_list->head,
                                      struct octeon_soft_command, node);

                status = OCTEON_REQUEST_PENDING;

                /* check if octeon has finished DMA'ing a response
                 * to where rptr is pointing to
                 */
                status64 = *sc->status_word;

                if (status64 != COMPLETION_WORD_INIT) {
                        /* This logic ensures that all 64b have been written.
                         * 1. check byte 0 for non-FF
                         * 2. if non-FF, then swap result from BE to host order
                         * 3. check byte 7 (swapped to 0) for non-FF
                         * 4. if non-FF, use the low 32-bit status code
                         * 5. if either byte 0 or byte 7 is FF, don't use status
                         */
                        if ((status64 & 0xff) != 0xff) {
                                octeon_swap_8B_data(&status64, 1);
                                if (((status64 & 0xff) != 0xff)) {
                                        /* retrieve 16-bit firmware status */
                                        status = (u32)(status64 & 0xffffULL);
                                        if (status) {
                                                status =
                                                  FIRMWARE_STATUS_CODE(status);
                                        } else {
                                                /* i.e. no error */
                                                status = OCTEON_REQUEST_DONE;
                                        }
                                }
                        }
                } else if (unlikely(force_quit) || (sc->expiry_time &&
                        time_after(jiffies, (unsigned long)sc->expiry_time))) {
                        struct octeon_instr_irh *irh =
                                (struct octeon_instr_irh *)&sc->cmd.cmd3.irh;

                        dev_err(&octeon_dev->pci_dev->dev, "%s: ", __func__);
                        dev_err(&octeon_dev->pci_dev->dev,
                                "cmd %x/%x/%llx/%llx failed, ",
                                irh->opcode, irh->subcode,
                                sc->cmd.cmd3.ossp[0], sc->cmd.cmd3.ossp[1]);
                        dev_err(&octeon_dev->pci_dev->dev,
                                "timeout (%ld, %ld)\n",
                                (long)jiffies, (long)sc->expiry_time);
                        status = OCTEON_REQUEST_TIMEOUT;
                }

                if (status != OCTEON_REQUEST_PENDING) {
                        sc->sc_status = status;

                        /* we have received a response or we have timed out */
                        /* remove node from linked list */
                        list_del(&sc->node);
                        atomic_dec(&octeon_dev->response_list
                                   [OCTEON_ORDERED_SC_LIST].
                                   pending_req_count);

                        if (!sc->callback) {
                                atomic_inc(&octeon_dev->response_list
                                           [OCTEON_DONE_SC_LIST].
                                           pending_req_count);
                                list_add_tail(&sc->node,
                                              &octeon_dev->response_list
                                              [OCTEON_DONE_SC_LIST].head);

                                if (unlikely(READ_ONCE(sc->caller_is_done))) {
                                        /* caller does not wait for response
                                         * from firmware
                                         */
                                        if (status != OCTEON_REQUEST_DONE) {
                                                struct octeon_instr_irh *irh;

                                                irh =
                                                    (struct octeon_instr_irh *)
                                                    &sc->cmd.cmd3.irh;
                                                dev_dbg
                                                    (&octeon_dev->pci_dev->dev,
                                                    "%s: sc failed: opcode=%x, ",
                                                    __func__, irh->opcode);
                                                dev_dbg
                                                    (&octeon_dev->pci_dev->dev,
                                                    "subcode=%x, ossp[0]=%llx, ",
                                                    irh->subcode,
                                                    sc->cmd.cmd3.ossp[0]);
                                                dev_dbg
                                                    (&octeon_dev->pci_dev->dev,
                                                    "ossp[1]=%llx, status=%d\n",
                                                    sc->cmd.cmd3.ossp[1],
                                                    status);
                                        }
                                } else {
                                        complete(&sc->complete);
                                }

                                spin_unlock_bh(&ordered_sc_list->lock);
                        } else {
                                /* sc with callback function */
                                if (status == OCTEON_REQUEST_TIMEOUT) {
                                        atomic_inc(&octeon_dev->response_list
                                                   [OCTEON_ZOMBIE_SC_LIST].
                                                   pending_req_count);
                                        list_add_tail(&sc->node,
                                                      &octeon_dev->response_list
                                                      [OCTEON_ZOMBIE_SC_LIST].
                                                      head);
                                }

                                spin_unlock_bh(&ordered_sc_list->lock);

                                sc->callback(octeon_dev, status,
                                             sc->callback_arg);
                                /* sc is freed by caller */
                        }

                        request_complete++;

                } else {
                        /* no response yet */
                        request_complete = 0;
                        spin_unlock_bh
                            (&ordered_sc_list->lock);
                }

                /* If we hit the Max Ordered requests to process every loop,
                 * we quit
                 * and let this function be invoked the next time the poll
                 * thread runs
                 * to process the remaining requests. This function can take up
                 * the entire CPU if there is no upper limit to the requests
                 * processed.
                 */
                if (request_complete >= resp_to_process)
                        break;
        } while (request_complete);

        return 0;
}

static void oct_poll_req_completion(struct work_struct *work)
{
        struct cavium_wk *wk = (struct cavium_wk *)work;
        struct octeon_device *oct = (struct octeon_device *)wk->ctxptr;
        struct cavium_wq *cwq = &oct->dma_comp_wq;

        lio_process_ordered_list(oct, 0);

        if (atomic_read(&oct->response_list
                        [OCTEON_ORDERED_SC_LIST].pending_req_count))
                queue_delayed_work(cwq->wq, &cwq->wk.work, msecs_to_jiffies(1));
}