// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *
 *  Bluetooth HCI UART driver for marvell devices
 *
 *  Copyright (C) 2016  Marvell International Ltd.
 *  Copyright (C) 2016  Intel Corporation
 */

#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"

#define HCI_FW_REQ_PKT 0xA5
#define HCI_CHIP_VER_PKT 0xAA

#define MRVL_ACK 0x5A
#define MRVL_NAK 0xBF
#define MRVL_RAW_DATA 0x1F

enum {
	STATE_CHIP_VER_PENDING,
	STATE_FW_REQ_PENDING,
};

struct mrvl_data {
	struct sk_buff *rx_skb;
	struct sk_buff_head txq;
	struct sk_buff_head rawq;
	unsigned long flags;
	unsigned int tx_len;
	u8 id, rev;
};

struct hci_mrvl_pkt {
	__le16 lhs;
	__le16 rhs;
} __packed;
#define HCI_MRVL_PKT_SIZE 4

static int mrvl_open(struct hci_uart *hu)
{
	struct mrvl_data *mrvl;

	BT_DBG("hu %p", hu);

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

	skb_queue_head_init(&mrvl->txq);
	skb_queue_head_init(&mrvl->rawq);

	set_bit(STATE_CHIP_VER_PENDING, &mrvl->flags);

	hu->priv = mrvl;
	return 0;
}

static int mrvl_close(struct hci_uart *hu)
{
	struct mrvl_data *mrvl = hu->priv;

	BT_DBG("hu %p", hu);

	skb_queue_purge(&mrvl->txq);
	skb_queue_purge(&mrvl->rawq);
	kfree_skb(mrvl->rx_skb);
	kfree(mrvl);

	hu->priv = NULL;
	return 0;
}

static int mrvl_flush(struct hci_uart *hu)
{
	struct mrvl_data *mrvl = hu->priv;

	BT_DBG("hu %p", hu);

	skb_queue_purge(&mrvl->txq);
	skb_queue_purge(&mrvl->rawq);

	return 0;
}

static struct sk_buff *mrvl_dequeue(struct hci_uart *hu)
{
	struct mrvl_data *mrvl = hu->priv;
	struct sk_buff *skb;

	skb = skb_dequeue(&mrvl->txq);
	if (!skb) {
		/* Any raw data ? */
		skb = skb_dequeue(&mrvl->rawq);
	} else {
		/* Prepend skb with frame type */
		memcpy(skb_push(skb, 1), &bt_cb(skb)->pkt_type, 1);
	}

	return skb;
}

static int mrvl_enqueue(struct hci_uart *hu, struct sk_buff *skb)
{
	struct mrvl_data *mrvl = hu->priv;

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

static void mrvl_send_ack(struct hci_uart *hu, unsigned char type)
{
	struct mrvl_data *mrvl = hu->priv;
	struct sk_buff *skb;

	/* No H4 payload, only 1 byte header */
	skb = bt_skb_alloc(0, GFP_ATOMIC);
	if (!skb) {
		bt_dev_err(hu->hdev, "Unable to alloc ack/nak packet");
		return;
	}
	hci_skb_pkt_type(skb) = type;

	skb_queue_tail(&mrvl->txq, skb);
	hci_uart_tx_wakeup(hu);
}

static int mrvl_recv_fw_req(struct hci_dev *hdev, struct sk_buff *skb)
{
	struct hci_mrvl_pkt *pkt = (void *)skb->data;
	struct hci_uart *hu = hci_get_drvdata(hdev);
	struct mrvl_data *mrvl = hu->priv;
	int ret = 0;

	if ((pkt->lhs ^ pkt->rhs) != 0xffff) {
		bt_dev_err(hdev, "Corrupted mrvl header");
		mrvl_send_ack(hu, MRVL_NAK);
		ret = -EINVAL;
		goto done;
	}
	mrvl_send_ack(hu, MRVL_ACK);

	if (!test_bit(STATE_FW_REQ_PENDING, &mrvl->flags)) {
		bt_dev_err(hdev, "Received unexpected firmware request");
		ret = -EINVAL;
		goto done;
	}

	mrvl->tx_len = le16_to_cpu(pkt->lhs);

	clear_bit(STATE_FW_REQ_PENDING, &mrvl->flags);
	smp_mb__after_atomic();
	wake_up_bit(&mrvl->flags, STATE_FW_REQ_PENDING);

done:
	kfree_skb(skb);
	return ret;
}

static int mrvl_recv_chip_ver(struct hci_dev *hdev, struct sk_buff *skb)
{
	struct hci_mrvl_pkt *pkt = (void *)skb->data;
	struct hci_uart *hu = hci_get_drvdata(hdev);
	struct mrvl_data *mrvl = hu->priv;
	u16 version = le16_to_cpu(pkt->lhs);
	int ret = 0;

	if ((pkt->lhs ^ pkt->rhs) != 0xffff) {
		bt_dev_err(hdev, "Corrupted mrvl header");
		mrvl_send_ack(hu, MRVL_NAK);
		ret = -EINVAL;
		goto done;
	}
	mrvl_send_ack(hu, MRVL_ACK);

	if (!test_bit(STATE_CHIP_VER_PENDING, &mrvl->flags)) {
		bt_dev_err(hdev, "Received unexpected chip version");
		goto done;
	}

	mrvl->id = version;
	mrvl->rev = version >> 8;

	bt_dev_info(hdev, "Controller id = %x, rev = %x", mrvl->id, mrvl->rev);

	clear_bit(STATE_CHIP_VER_PENDING, &mrvl->flags);
	smp_mb__after_atomic();
	wake_up_bit(&mrvl->flags, STATE_CHIP_VER_PENDING);

done:
	kfree_skb(skb);
	return ret;
}

#define HCI_RECV_CHIP_VER \
	.type = HCI_CHIP_VER_PKT, \
	.hlen = HCI_MRVL_PKT_SIZE, \
	.loff = 0, \
	.lsize = 0, \
	.maxlen = HCI_MRVL_PKT_SIZE

#define HCI_RECV_FW_REQ \
	.type = HCI_FW_REQ_PKT, \
	.hlen = HCI_MRVL_PKT_SIZE, \
	.loff = 0, \
	.lsize = 0, \
	.maxlen = HCI_MRVL_PKT_SIZE

static const struct h4_recv_pkt mrvl_recv_pkts[] = {
	{ H4_RECV_ACL,       .recv = hci_recv_frame     },
	{ H4_RECV_SCO,       .recv = hci_recv_frame     },
	{ H4_RECV_EVENT,     .recv = hci_recv_frame     },
	{ HCI_RECV_FW_REQ,   .recv = mrvl_recv_fw_req   },
	{ HCI_RECV_CHIP_VER, .recv = mrvl_recv_chip_ver },
};

static int mrvl_recv(struct hci_uart *hu, const void *data, int count)
{
	struct mrvl_data *mrvl = hu->priv;

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

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

	return count;
}

static int mrvl_load_firmware(struct hci_dev *hdev, const char *name)
{
	struct hci_uart *hu = hci_get_drvdata(hdev);
	struct mrvl_data *mrvl = hu->priv;
	const struct firmware *fw = NULL;
	const u8 *fw_ptr, *fw_max;
	int err;

	err = request_firmware(&fw, name, &hdev->dev);
	if (err < 0) {
		bt_dev_err(hdev, "Failed to load firmware file %s", name);
		return err;
	}

	fw_ptr = fw->data;
	fw_max = fw->data + fw->size;

	bt_dev_info(hdev, "Loading %s", name);

	set_bit(STATE_FW_REQ_PENDING, &mrvl->flags);

	while (fw_ptr <= fw_max) {
		struct sk_buff *skb;

		/* Controller drives the firmware load by sending firmware
		 * request packets containing the expected fragment size.
		 */
		err = wait_on_bit_timeout(&mrvl->flags, STATE_FW_REQ_PENDING,
					  TASK_INTERRUPTIBLE,
					  msecs_to_jiffies(2000));
		if (err == 1) {
			bt_dev_err(hdev, "Firmware load interrupted");
			err = -EINTR;
			break;
		} else if (err) {
			bt_dev_err(hdev, "Firmware request timeout");
			err = -ETIMEDOUT;
			break;
		}

		bt_dev_dbg(hdev, "Firmware request, expecting %d bytes",
			   mrvl->tx_len);

		if (fw_ptr == fw_max) {
			/* Controller requests a null size once firmware is
			 * fully loaded. If controller expects more data, there
			 * is an issue.
			 */
			if (!mrvl->tx_len) {
				bt_dev_info(hdev, "Firmware loading complete");
			} else {
				bt_dev_err(hdev, "Firmware loading failure");
				err = -EINVAL;
			}
			break;
		}

		if (fw_ptr + mrvl->tx_len > fw_max) {
			mrvl->tx_len = fw_max - fw_ptr;
			bt_dev_dbg(hdev, "Adjusting tx_len to %d",
				   mrvl->tx_len);
		}

		skb = bt_skb_alloc(mrvl->tx_len, GFP_KERNEL);
		if (!skb) {
			bt_dev_err(hdev, "Failed to alloc mem for FW packet");
			err = -ENOMEM;
			break;
		}
		bt_cb(skb)->pkt_type = MRVL_RAW_DATA;

		skb_put_data(skb, fw_ptr, mrvl->tx_len);
		fw_ptr += mrvl->tx_len;

		set_bit(STATE_FW_REQ_PENDING, &mrvl->flags);

		skb_queue_tail(&mrvl->rawq, skb);
		hci_uart_tx_wakeup(hu);
	}

	release_firmware(fw);
	return err;
}

static int mrvl_setup(struct hci_uart *hu)
{
	int err;

	hci_uart_set_flow_control(hu, true);

	err = mrvl_load_firmware(hu->hdev, "mrvl/helper_uart_3000000.bin");
	if (err) {
		bt_dev_err(hu->hdev, "Unable to download firmware helper");
		return -EINVAL;
	}

	/* Let the final ack go out before switching the baudrate */
	hci_uart_wait_until_sent(hu);

	hci_uart_set_baudrate(hu, 3000000);
	hci_uart_set_flow_control(hu, false);

	err = mrvl_load_firmware(hu->hdev, "mrvl/uart8897_bt.bin");
	if (err)
		return err;

	return 0;
}

static const struct hci_uart_proto mrvl_proto = {
	.id		= HCI_UART_MRVL,
	.name		= "Marvell",
	.init_speed	= 115200,
	.open		= mrvl_open,
	.close		= mrvl_close,
	.flush		= mrvl_flush,
	.setup		= mrvl_setup,
	.recv		= mrvl_recv,
	.enqueue	= mrvl_enqueue,
	.dequeue	= mrvl_dequeue,
};

int __init mrvl_init(void)
{
	return hci_uart_register_proto(&mrvl_proto);
}

int __exit mrvl_deinit(void)
{
	return hci_uart_unregister_proto(&mrvl_proto);
}