/*
 * This file is part of the Chelsio T4/T5/T6 Ethernet driver for Linux.
 *
 * Copyright (C) 2011-2016 Chelsio Communications.  All rights reserved.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation.
 *
 * Written and Maintained by:
 * Manoj Malviya (manojmalviya@chelsio.com)
 * Atul Gupta (atul.gupta@chelsio.com)
 * Jitendra Lulla (jlulla@chelsio.com)
 * Yeshaswi M R Gowda (yeshaswi@chelsio.com)
 * Harsh Jain (harsh@chelsio.com)
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/skbuff.h>

#include <crypto/aes.h>
#include <crypto/hash.h>

#include "t4_msg.h"
#include "chcr_core.h"
#include "cxgb4_uld.h"

static struct chcr_driver_data drv_data;

typedef int (*chcr_handler_func)(struct adapter *adap, unsigned char *input);
static int cpl_fw6_pld_handler(struct adapter *adap, unsigned char *input);
static void *chcr_uld_add(const struct cxgb4_lld_info *lld);
static int chcr_uld_state_change(void *handle, enum cxgb4_state state);

static chcr_handler_func work_handlers[NUM_CPL_CMDS] = {
        [CPL_FW6_PLD] = cpl_fw6_pld_handler,
};

static struct cxgb4_uld_info chcr_uld_info = {
        .name = DRV_MODULE_NAME,
        .nrxq = MAX_ULD_QSETS,
        /* Max ntxq will be derived from fw config file*/
        .rxq_size = 1024,
        .add = chcr_uld_add,
        .state_change = chcr_uld_state_change,
        .rx_handler = chcr_uld_rx_handler,
};

static void detach_work_fn(struct work_struct *work)
{
        struct chcr_dev *dev;

        dev = container_of(work, struct chcr_dev, detach_work.work);

        if (atomic_read(&dev->inflight)) {
                dev->wqretry--;
                if (dev->wqretry) {
                        pr_debug("Request Inflight Count %d\n",
                                atomic_read(&dev->inflight));

                        schedule_delayed_work(&dev->detach_work, WQ_DETACH_TM);
                } else {
                        WARN(1, "CHCR:%d request Still Pending\n",
                                atomic_read(&dev->inflight));
                        complete(&dev->detach_comp);
                }
        } else {
                complete(&dev->detach_comp);
        }
}

struct uld_ctx *assign_chcr_device(void)
{
        struct uld_ctx *u_ctx = NULL;

        /*
         * When multiple devices are present in system select
         * device in round-robin fashion for crypto operations
         * Although One session must use the same device to
         * maintain request-response ordering.
         */
        mutex_lock(&drv_data.drv_mutex);
        if (!list_empty(&drv_data.act_dev)) {
                u_ctx = drv_data.last_dev;
                if (list_is_last(&drv_data.last_dev->entry, &drv_data.act_dev))
                        drv_data.last_dev = list_first_entry(&drv_data.act_dev,
                                                  struct uld_ctx, entry);
                else
                        drv_data.last_dev =
                                list_next_entry(drv_data.last_dev, entry);
        }
        mutex_unlock(&drv_data.drv_mutex);
        return u_ctx;
}

static void chcr_dev_add(struct uld_ctx *u_ctx)
{
        struct chcr_dev *dev;

        dev = &u_ctx->dev;
        dev->state = CHCR_ATTACH;
        atomic_set(&dev->inflight, 0);
        mutex_lock(&drv_data.drv_mutex);
        list_move(&u_ctx->entry, &drv_data.act_dev);
        if (!drv_data.last_dev)
                drv_data.last_dev = u_ctx;
        mutex_unlock(&drv_data.drv_mutex);
}

static void chcr_dev_init(struct uld_ctx *u_ctx)
{
        struct chcr_dev *dev;

        dev = &u_ctx->dev;
        spin_lock_init(&dev->lock_chcr_dev);
        INIT_DELAYED_WORK(&dev->detach_work, detach_work_fn);
        init_completion(&dev->detach_comp);
        dev->state = CHCR_INIT;
        dev->wqretry = WQ_RETRY;
        atomic_inc(&drv_data.dev_count);
        atomic_set(&dev->inflight, 0);
        mutex_lock(&drv_data.drv_mutex);
        list_add_tail(&u_ctx->entry, &drv_data.inact_dev);
        mutex_unlock(&drv_data.drv_mutex);
}

static int chcr_dev_move(struct uld_ctx *u_ctx)
{
        mutex_lock(&drv_data.drv_mutex);
        if (drv_data.last_dev == u_ctx) {
                if (list_is_last(&drv_data.last_dev->entry, &drv_data.act_dev))
                        drv_data.last_dev = list_first_entry(&drv_data.act_dev,
                                                  struct uld_ctx, entry);
                else
                        drv_data.last_dev =
                                list_next_entry(drv_data.last_dev, entry);
        }
        list_move(&u_ctx->entry, &drv_data.inact_dev);
        if (list_empty(&drv_data.act_dev))
                drv_data.last_dev = NULL;
        atomic_dec(&drv_data.dev_count);
        mutex_unlock(&drv_data.drv_mutex);

        return 0;
}

static int cpl_fw6_pld_handler(struct adapter *adap,
                               unsigned char *input)
{
        struct crypto_async_request *req;
        struct cpl_fw6_pld *fw6_pld;
        u32 ack_err_status = 0;
        int error_status = 0;

        fw6_pld = (struct cpl_fw6_pld *)input;
        req = (struct crypto_async_request *)(uintptr_t)be64_to_cpu(
                                                    fw6_pld->data[1]);

        ack_err_status =
                ntohl(*(__be32 *)((unsigned char *)&fw6_pld->data[0] + 4));
        if (CHK_MAC_ERR_BIT(ack_err_status) || CHK_PAD_ERR_BIT(ack_err_status))
                error_status = -EBADMSG;
        /* call completion callback with failure status */
        if (req) {
                error_status = chcr_handle_resp(req, input, error_status);
        } else {
                pr_err("Incorrect request address from the firmware\n");
                return -EFAULT;
        }
        if (error_status)
                atomic_inc(&adap->chcr_stats.error);

        return 0;
}

int chcr_send_wr(struct sk_buff *skb)
{
        return cxgb4_crypto_send(skb->dev, skb);
}

static void *chcr_uld_add(const struct cxgb4_lld_info *lld)
{
        struct uld_ctx *u_ctx;

        /* Create the device and add it in the device list */
        pr_info_once("%s\n", DRV_DESC);
        if (!(lld->ulp_crypto & ULP_CRYPTO_LOOKASIDE))
                return ERR_PTR(-EOPNOTSUPP);

        /* Create the device and add it in the device list */
        u_ctx = kzalloc_obj(*u_ctx);
        if (!u_ctx) {
                u_ctx = ERR_PTR(-ENOMEM);
                goto out;
        }
        u_ctx->lldi = *lld;
        chcr_dev_init(u_ctx);
out:
        return u_ctx;
}

int chcr_uld_rx_handler(void *handle, const __be64 *rsp,
                        const struct pkt_gl *pgl)
{
        struct uld_ctx *u_ctx = (struct uld_ctx *)handle;
        struct chcr_dev *dev = &u_ctx->dev;
        struct adapter *adap = padap(dev);
        const struct cpl_fw6_pld *rpl = (struct cpl_fw6_pld *)rsp;

        if (!work_handlers[rpl->opcode]) {
                pr_err("Unsupported opcode %d received\n", rpl->opcode);
                return 0;
        }

        if (!pgl)
                work_handlers[rpl->opcode](adap, (unsigned char *)&rsp[1]);
        else
                work_handlers[rpl->opcode](adap, pgl->va);
        return 0;
}

static void chcr_detach_device(struct uld_ctx *u_ctx)
{
        struct chcr_dev *dev = &u_ctx->dev;

        if (dev->state == CHCR_DETACH) {
                pr_debug("Detached Event received for already detach device\n");
                return;
        }
        dev->state = CHCR_DETACH;
        if (atomic_read(&dev->inflight) != 0) {
                schedule_delayed_work(&dev->detach_work, WQ_DETACH_TM);
                wait_for_completion(&dev->detach_comp);
        }

        // Move u_ctx to inactive_dev list
        chcr_dev_move(u_ctx);
}

static int chcr_uld_state_change(void *handle, enum cxgb4_state state)
{
        struct uld_ctx *u_ctx = handle;
        int ret = 0;

        switch (state) {
        case CXGB4_STATE_UP:
                if (u_ctx->dev.state != CHCR_INIT) {
                        // ALready Initialised.
                        return 0;
                }
                chcr_dev_add(u_ctx);
                ret = start_crypto();
                break;

        case CXGB4_STATE_DETACH:
                chcr_detach_device(u_ctx);
                if (!atomic_read(&drv_data.dev_count))
                        stop_crypto();
                break;

        case CXGB4_STATE_START_RECOVERY:
        case CXGB4_STATE_DOWN:
        default:
                break;
        }
        return ret;
}

static int __init chcr_crypto_init(void)
{
        INIT_LIST_HEAD(&drv_data.act_dev);
        INIT_LIST_HEAD(&drv_data.inact_dev);
        atomic_set(&drv_data.dev_count, 0);
        mutex_init(&drv_data.drv_mutex);
        drv_data.last_dev = NULL;
        cxgb4_register_uld(CXGB4_ULD_CRYPTO, &chcr_uld_info);

        return 0;
}

static void __exit chcr_crypto_exit(void)
{
        struct uld_ctx *u_ctx, *tmp;
        struct adapter *adap;

        stop_crypto();
        cxgb4_unregister_uld(CXGB4_ULD_CRYPTO);
        /* Remove all devices from list */
        mutex_lock(&drv_data.drv_mutex);
        list_for_each_entry_safe(u_ctx, tmp, &drv_data.act_dev, entry) {
                adap = padap(&u_ctx->dev);
                memset(&adap->chcr_stats, 0, sizeof(adap->chcr_stats));
                list_del(&u_ctx->entry);
                kfree(u_ctx);
        }
        list_for_each_entry_safe(u_ctx, tmp, &drv_data.inact_dev, entry) {
                adap = padap(&u_ctx->dev);
                memset(&adap->chcr_stats, 0, sizeof(adap->chcr_stats));
                list_del(&u_ctx->entry);
                kfree(u_ctx);
        }
        mutex_unlock(&drv_data.drv_mutex);
}

module_init(chcr_crypto_init);
module_exit(chcr_crypto_exit);

MODULE_DESCRIPTION("Crypto Co-processor for Chelsio Terminator cards.");
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Chelsio Communications");