/*
 *
 *  Bluetooth HCI UART driver for Intel/AG6xx devices
 *
 *  Copyright (C) 2016  Intel Corporation
 *
 *
 *  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; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 */

#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/skbuff.h>
#include <linux/firmware.h>
#include <linux/module.h>
#include <linux/tty.h>

#include <net/bluetooth/bluetooth.h>
#include <net/bluetooth/hci_core.h>

#include "hci_uart.h"
#include "btintel.h"

struct ag6xx_data {
        struct sk_buff *rx_skb;
        struct sk_buff_head txq;
};

struct pbn_entry {
        __le32 addr;
        __le32 plen;
        __u8 data[0];
} __packed;

static int ag6xx_open(struct hci_uart *hu)
{
        struct ag6xx_data *ag6xx;

        BT_DBG("hu %p", hu);

        ag6xx = kzalloc(sizeof(*ag6xx), GFP_KERNEL);
        if (!ag6xx)
                return -ENOMEM;

        skb_queue_head_init(&ag6xx->txq);

        hu->priv = ag6xx;
        return 0;
}

static int ag6xx_close(struct hci_uart *hu)
{
        struct ag6xx_data *ag6xx = hu->priv;

        BT_DBG("hu %p", hu);

        skb_queue_purge(&ag6xx->txq);
        kfree_skb(ag6xx->rx_skb);
        kfree(ag6xx);

        hu->priv = NULL;
        return 0;
}

static int ag6xx_flush(struct hci_uart *hu)
{
        struct ag6xx_data *ag6xx = hu->priv;

        BT_DBG("hu %p", hu);

        skb_queue_purge(&ag6xx->txq);
        return 0;
}

static struct sk_buff *ag6xx_dequeue(struct hci_uart *hu)
{
        struct ag6xx_data *ag6xx = hu->priv;
        struct sk_buff *skb;

        skb = skb_dequeue(&ag6xx->txq);
        if (!skb)
                return skb;

        /* Prepend skb with frame type */
        memcpy(skb_push(skb, 1), &bt_cb(skb)->pkt_type, 1);
        return skb;
}

static int ag6xx_enqueue(struct hci_uart *hu, struct sk_buff *skb)
{
        struct ag6xx_data *ag6xx = hu->priv;

        skb_queue_tail(&ag6xx->txq, skb);
        return 0;
}

static const struct h4_recv_pkt ag6xx_recv_pkts[] = {
        { H4_RECV_ACL,    .recv = hci_recv_frame   },
        { H4_RECV_SCO,    .recv = hci_recv_frame   },
        { H4_RECV_EVENT,  .recv = hci_recv_frame   },
};

static int ag6xx_recv(struct hci_uart *hu, const void *data, int count)
{
        struct ag6xx_data *ag6xx = hu->priv;

        if (!test_bit(HCI_UART_REGISTERED, &hu->flags))
                return -EUNATCH;

        ag6xx->rx_skb = h4_recv_buf(hu->hdev, ag6xx->rx_skb, data, count,
                                    ag6xx_recv_pkts,
                                    ARRAY_SIZE(ag6xx_recv_pkts));
        if (IS_ERR(ag6xx->rx_skb)) {
                int err = PTR_ERR(ag6xx->rx_skb);
                bt_dev_err(hu->hdev, "Frame reassembly failed (%d)", err);
                ag6xx->rx_skb = NULL;
                return err;
        }

        return count;
}

static int intel_mem_write(struct hci_dev *hdev, u32 addr, u32 plen,
                           const void *data)
{
        /* Can write a maximum of 247 bytes per HCI command.
         * HCI cmd Header (3), Intel mem write header (6), data (247).
         */
        while (plen > 0) {
                struct sk_buff *skb;
                u8 cmd_param[253], fragment_len = (plen > 247) ? 247 : plen;
                __le32 leaddr = cpu_to_le32(addr);

                memcpy(cmd_param, &leaddr, 4);
                cmd_param[4] = 0;
                cmd_param[5] = fragment_len;
                memcpy(cmd_param + 6, data, fragment_len);

                skb = __hci_cmd_sync(hdev, 0xfc8e, fragment_len + 6, cmd_param,
                                     HCI_INIT_TIMEOUT);
                if (IS_ERR(skb))
                        return PTR_ERR(skb);
                kfree_skb(skb);

                plen -= fragment_len;
                data += fragment_len;
                addr += fragment_len;
        }

        return 0;
}

static int ag6xx_setup(struct hci_uart *hu)
{
        struct hci_dev *hdev = hu->hdev;
        struct sk_buff *skb;
        struct intel_version ver;
        const struct firmware *fw;
        const u8 *fw_ptr;
        char fwname[64];
        bool patched = false;
        int err;

        hu->hdev->set_diag = btintel_set_diag;
        hu->hdev->set_bdaddr = btintel_set_bdaddr;

        err = btintel_enter_mfg(hdev);
        if (err)
                return err;

        err = btintel_read_version(hdev, &ver);
        if (err)
                return err;

        btintel_version_info(hdev, &ver);

        /* The hardware platform number has a fixed value of 0x37 and
         * for now only accept this single value.
         */
        if (ver.hw_platform != 0x37) {
                bt_dev_err(hdev, "Unsupported Intel hardware platform: 0x%X",
                           ver.hw_platform);
                return -EINVAL;
        }

        /* Only the hardware variant iBT 2.1 (AG6XX) is supported by this
         * firmware setup method.
         */
        if (ver.hw_variant != 0x0a) {
                bt_dev_err(hdev, "Unsupported Intel hardware variant: 0x%x",
                           ver.hw_variant);
                return -EINVAL;
        }

        snprintf(fwname, sizeof(fwname), "intel/ibt-hw-%x.%x.bddata",
                 ver.hw_platform, ver.hw_variant);

        err = request_firmware(&fw, fwname, &hdev->dev);
        if (err < 0) {
                bt_dev_err(hdev, "Failed to open Intel bddata file: %s (%d)",
                           fwname, err);
                goto patch;
        }
        fw_ptr = fw->data;

        bt_dev_info(hdev, "Applying bddata (%s)", fwname);

        skb = __hci_cmd_sync_ev(hdev, 0xfc2f, fw->size, fw->data,
                                HCI_EV_CMD_STATUS, HCI_CMD_TIMEOUT);
        if (IS_ERR(skb)) {
                bt_dev_err(hdev, "Applying bddata failed (%ld)", PTR_ERR(skb));
                release_firmware(fw);
                return PTR_ERR(skb);
        }
        kfree_skb(skb);

        release_firmware(fw);

patch:
        /* If there is no applied patch, fw_patch_num is always 0x00. In other
         * cases, current firmware is already patched. No need to patch it.
         */
        if (ver.fw_patch_num) {
                bt_dev_info(hdev, "Device is already patched. patch num: %02x",
                            ver.fw_patch_num);
                patched = true;
                goto complete;
        }

        snprintf(fwname, sizeof(fwname),
                 "intel/ibt-hw-%x.%x.%x-fw-%x.%x.%x.%x.%x.pbn",
                 ver.hw_platform, ver.hw_variant, ver.hw_revision,
                 ver.fw_variant,  ver.fw_revision, ver.fw_build_num,
                 ver.fw_build_ww, ver.fw_build_yy);

        err = request_firmware(&fw, fwname, &hdev->dev);
        if (err < 0) {
                bt_dev_err(hdev, "Failed to open Intel patch file: %s(%d)",
                           fwname, err);
                goto complete;
        }
        fw_ptr = fw->data;

        bt_dev_info(hdev, "Patching firmware file (%s)", fwname);

        /* PBN patch file contains a list of binary patches to be applied on top
         * of the embedded firmware. Each patch entry header contains the target
         * address and patch size.
         *
         * Patch entry:
         * | addr(le) | patch_len(le) | patch_data |
         * | 4 Bytes  |    4 Bytes    |   n Bytes  |
         *
         * PBN file is terminated by a patch entry whose address is 0xffffffff.
         */
        while (fw->size > fw_ptr - fw->data) {
                struct pbn_entry *pbn = (void *)fw_ptr;
                u32 addr, plen;

                if (pbn->addr == 0xffffffff) {
                        bt_dev_info(hdev, "Patching complete");
                        patched = true;
                        break;
                }

                addr = le32_to_cpu(pbn->addr);
                plen = le32_to_cpu(pbn->plen);

                if (fw->data + fw->size <= pbn->data + plen) {
                        bt_dev_info(hdev, "Invalid patch len (%d)", plen);
                        break;
                }

                bt_dev_info(hdev, "Patching %td/%zu", (fw_ptr - fw->data),
                            fw->size);

                err = intel_mem_write(hdev, addr, plen, pbn->data);
                if (err) {
                        bt_dev_err(hdev, "Patching failed");
                        break;
                }

                fw_ptr = pbn->data + plen;
        }

        release_firmware(fw);

complete:
        /* Exit manufacturing mode and reset */
        err = btintel_exit_mfg(hdev, true, patched);
        if (err)
                return err;

        /* Set the event mask for Intel specific vendor events. This enables
         * a few extra events that are useful during general operation.
         */
        btintel_set_event_mask_mfg(hdev, false);

        btintel_check_bdaddr(hdev);
        return 0;
}

static const struct hci_uart_proto ag6xx_proto = {
        .id             = HCI_UART_AG6XX,
        .name           = "AG6XX",
        .manufacturer   = 2,
        .open           = ag6xx_open,
        .close          = ag6xx_close,
        .flush          = ag6xx_flush,
        .setup          = ag6xx_setup,
        .recv           = ag6xx_recv,
        .enqueue        = ag6xx_enqueue,
        .dequeue        = ag6xx_dequeue,
};

int __init ag6xx_init(void)
{
        return hci_uart_register_proto(&ag6xx_proto);
}

int __exit ag6xx_deinit(void)
{
        return hci_uart_unregister_proto(&ag6xx_proto);
}