/*
 * Copyright (c) 2017 Redpine Signals Inc.
 *
 * Permission to use, copy, modify, and/or distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */
#include <linux/module.h>
#include <linux/kernel.h>
#include <net/bluetooth/bluetooth.h>
#include <net/bluetooth/hci_core.h>
#include <linux/unaligned.h>
#include <net/rsi_91x.h>

#define RSI_DMA_ALIGN   8
#define RSI_FRAME_DESC_SIZE     16
#define RSI_HEADROOM_FOR_BT_HAL (RSI_FRAME_DESC_SIZE + RSI_DMA_ALIGN)

struct rsi_hci_adapter {
        void *priv;
        struct rsi_proto_ops *proto_ops;
        struct hci_dev *hdev;
};

static int rsi_hci_open(struct hci_dev *hdev)
{
        return 0;
}

static int rsi_hci_close(struct hci_dev *hdev)
{
        return 0;
}

static int rsi_hci_flush(struct hci_dev *hdev)
{
        return 0;
}

static int rsi_hci_send_pkt(struct hci_dev *hdev, struct sk_buff *skb)
{
        struct rsi_hci_adapter *h_adapter = hci_get_drvdata(hdev);
        struct sk_buff *new_skb = NULL;

        switch (hci_skb_pkt_type(skb)) {
        case HCI_COMMAND_PKT:
                hdev->stat.cmd_tx++;
                break;
        case HCI_ACLDATA_PKT:
                hdev->stat.acl_tx++;
                break;
        case HCI_SCODATA_PKT:
                hdev->stat.sco_tx++;
                break;
        }

        if (skb_headroom(skb) < RSI_HEADROOM_FOR_BT_HAL) {
                /* Insufficient skb headroom - allocate a new skb */
                new_skb = skb_realloc_headroom(skb, RSI_HEADROOM_FOR_BT_HAL);
                if (unlikely(!new_skb))
                        return -ENOMEM;
                bt_cb(new_skb)->pkt_type = hci_skb_pkt_type(skb);
                kfree_skb(skb);
                skb = new_skb;
                if (!IS_ALIGNED((unsigned long)skb->data, RSI_DMA_ALIGN)) {
                        u8 *skb_data = skb->data;
                        int skb_len = skb->len;

                        skb_push(skb, RSI_DMA_ALIGN);
                        skb_pull(skb, PTR_ALIGN(skb->data,
                                                RSI_DMA_ALIGN) - skb->data);
                        memmove(skb->data, skb_data, skb_len);
                        skb_trim(skb, skb_len);
                }
        }

        return h_adapter->proto_ops->coex_send_pkt(h_adapter->priv, skb,
                                                   RSI_BT_Q);
}

static int rsi_hci_recv_pkt(void *priv, const u8 *pkt)
{
        struct rsi_hci_adapter *h_adapter = priv;
        struct hci_dev *hdev = h_adapter->hdev;
        struct sk_buff *skb;
        int pkt_len = get_unaligned_le16(pkt) & 0x0fff;

        skb = dev_alloc_skb(pkt_len);
        if (!skb)
                return -ENOMEM;

        memcpy(skb->data, pkt + RSI_FRAME_DESC_SIZE, pkt_len);
        skb_put(skb, pkt_len);
        h_adapter->hdev->stat.byte_rx += skb->len;

        hci_skb_pkt_type(skb) = pkt[14];

        return hci_recv_frame(hdev, skb);
}

static int rsi_hci_attach(void *priv, struct rsi_proto_ops *ops)
{
        struct rsi_hci_adapter *h_adapter = NULL;
        struct hci_dev *hdev;
        int err = 0;

        h_adapter = kzalloc_obj(*h_adapter);
        if (!h_adapter)
                return -ENOMEM;

        h_adapter->priv = priv;
        ops->set_bt_context(priv, h_adapter);
        h_adapter->proto_ops = ops;

        hdev = hci_alloc_dev();
        if (!hdev) {
                BT_ERR("Failed to alloc HCI device");
                goto err;
        }

        h_adapter->hdev = hdev;

        if (ops->get_host_intf(priv) == RSI_HOST_INTF_SDIO)
                hdev->bus = HCI_SDIO;
        else
                hdev->bus = HCI_USB;

        hci_set_drvdata(hdev, h_adapter);
        hdev->open = rsi_hci_open;
        hdev->close = rsi_hci_close;
        hdev->flush = rsi_hci_flush;
        hdev->send = rsi_hci_send_pkt;

        err = hci_register_dev(hdev);
        if (err < 0) {
                BT_ERR("HCI registration failed with errcode %d", err);
                hci_free_dev(hdev);
                goto err;
        }

        return 0;
err:
        h_adapter->hdev = NULL;
        kfree(h_adapter);
        return -EINVAL;
}

static void rsi_hci_detach(void *priv)
{
        struct rsi_hci_adapter *h_adapter = priv;
        struct hci_dev *hdev;

        if (!h_adapter)
                return;

        hdev = h_adapter->hdev;
        if (hdev) {
                hci_unregister_dev(hdev);
                hci_free_dev(hdev);
                h_adapter->hdev = NULL;
        }

        kfree(h_adapter);
}

const struct rsi_mod_ops rsi_bt_ops = {
        .attach = rsi_hci_attach,
        .detach = rsi_hci_detach,
        .recv_pkt = rsi_hci_recv_pkt,
};
EXPORT_SYMBOL(rsi_bt_ops);

static int rsi_91x_bt_module_init(void)
{
        return 0;
}

static void rsi_91x_bt_module_exit(void)
{
        return;
}

module_init(rsi_91x_bt_module_init);
module_exit(rsi_91x_bt_module_exit);
MODULE_AUTHOR("Redpine Signals Inc");
MODULE_DESCRIPTION("RSI BT driver");
MODULE_LICENSE("Dual BSD/GPL");