// SPDX-License-Identifier: GPL-2.0
/*
 * BlueZ - Bluetooth protocol stack for Linux
 *
 * Copyright (C) 2021 Intel Corporation
 */

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

#include "hci_request.h"
#include "smp.h"

static void hci_cmd_sync_complete(struct hci_dev *hdev, u8 result, u16 opcode,
				  struct sk_buff *skb)
{
	bt_dev_dbg(hdev, "result 0x%2.2x", result);

	if (hdev->req_status != HCI_REQ_PEND)
		return;

	hdev->req_result = result;
	hdev->req_status = HCI_REQ_DONE;

	wake_up_interruptible(&hdev->req_wait_q);
}

static struct sk_buff *hci_cmd_sync_alloc(struct hci_dev *hdev, u16 opcode,
					  u32 plen, const void *param,
					  struct sock *sk)
{
	int len = HCI_COMMAND_HDR_SIZE + plen;
	struct hci_command_hdr *hdr;
	struct sk_buff *skb;

	skb = bt_skb_alloc(len, GFP_ATOMIC);
	if (!skb)
		return NULL;

	hdr = skb_put(skb, HCI_COMMAND_HDR_SIZE);
	hdr->opcode = cpu_to_le16(opcode);
	hdr->plen   = plen;

	if (plen)
		skb_put_data(skb, param, plen);

	bt_dev_dbg(hdev, "skb len %d", skb->len);

	hci_skb_pkt_type(skb) = HCI_COMMAND_PKT;
	hci_skb_opcode(skb) = opcode;

	return skb;
}

static void hci_cmd_sync_add(struct hci_request *req, u16 opcode, u32 plen,
			     const void *param, u8 event, struct sock *sk)
{
	struct hci_dev *hdev = req->hdev;
	struct sk_buff *skb;

	bt_dev_dbg(hdev, "opcode 0x%4.4x plen %d", opcode, plen);

	/* If an error occurred during request building, there is no point in
	 * queueing the HCI command. We can simply return.
	 */
	if (req->err)
		return;

	skb = hci_cmd_sync_alloc(hdev, opcode, plen, param, sk);
	if (!skb) {
		bt_dev_err(hdev, "no memory for command (opcode 0x%4.4x)",
			   opcode);
		req->err = -ENOMEM;
		return;
	}

	if (skb_queue_empty(&req->cmd_q))
		bt_cb(skb)->hci.req_flags |= HCI_REQ_START;

	bt_cb(skb)->hci.req_event = event;

	skb_queue_tail(&req->cmd_q, skb);
}

static int hci_cmd_sync_run(struct hci_request *req)
{
	struct hci_dev *hdev = req->hdev;
	struct sk_buff *skb;
	unsigned long flags;

	bt_dev_dbg(hdev, "length %u", skb_queue_len(&req->cmd_q));

	/* If an error occurred during request building, remove all HCI
	 * commands queued on the HCI request queue.
	 */
	if (req->err) {
		skb_queue_purge(&req->cmd_q);
		return req->err;
	}

	/* Do not allow empty requests */
	if (skb_queue_empty(&req->cmd_q))
		return -ENODATA;

	skb = skb_peek_tail(&req->cmd_q);
	bt_cb(skb)->hci.req_complete_skb = hci_cmd_sync_complete;
	bt_cb(skb)->hci.req_flags |= HCI_REQ_SKB;

	spin_lock_irqsave(&hdev->cmd_q.lock, flags);
	skb_queue_splice_tail(&req->cmd_q, &hdev->cmd_q);
	spin_unlock_irqrestore(&hdev->cmd_q.lock, flags);

	queue_work(hdev->workqueue, &hdev->cmd_work);

	return 0;
}

/* This function requires the caller holds hdev->req_lock. */
struct sk_buff *__hci_cmd_sync_sk(struct hci_dev *hdev, u16 opcode, u32 plen,
				  const void *param, u8 event, u32 timeout,
				  struct sock *sk)
{
	struct hci_request req;
	struct sk_buff *skb;
	int err = 0;

	bt_dev_dbg(hdev, "");

	hci_req_init(&req, hdev);

	hci_cmd_sync_add(&req, opcode, plen, param, event, sk);

	hdev->req_status = HCI_REQ_PEND;

	err = hci_cmd_sync_run(&req);
	if (err < 0)
		return ERR_PTR(err);

	err = wait_event_interruptible_timeout(hdev->req_wait_q,
					       hdev->req_status != HCI_REQ_PEND,
					       timeout);

	if (err == -ERESTARTSYS)
		return ERR_PTR(-EINTR);

	switch (hdev->req_status) {
	case HCI_REQ_DONE:
		err = -bt_to_errno(hdev->req_result);
		break;

	case HCI_REQ_CANCELED:
		err = -hdev->req_result;
		break;

	default:
		err = -ETIMEDOUT;
		break;
	}

	hdev->req_status = 0;
	hdev->req_result = 0;
	skb = hdev->req_skb;
	hdev->req_skb = NULL;

	bt_dev_dbg(hdev, "end: err %d", err);

	if (err < 0) {
		kfree_skb(skb);
		return ERR_PTR(err);
	}

	if (!skb)
		return ERR_PTR(-ENODATA);

	return skb;
}
EXPORT_SYMBOL(__hci_cmd_sync_sk);

/* This function requires the caller holds hdev->req_lock. */
struct sk_buff *__hci_cmd_sync(struct hci_dev *hdev, u16 opcode, u32 plen,
			       const void *param, u32 timeout)
{
	return __hci_cmd_sync_sk(hdev, opcode, plen, param, 0, timeout, NULL);
}
EXPORT_SYMBOL(__hci_cmd_sync);

/* Send HCI command and wait for command complete event */
struct sk_buff *hci_cmd_sync(struct hci_dev *hdev, u16 opcode, u32 plen,
			     const void *param, u32 timeout)
{
	struct sk_buff *skb;

	if (!test_bit(HCI_UP, &hdev->flags))
		return ERR_PTR(-ENETDOWN);

	bt_dev_dbg(hdev, "opcode 0x%4.4x plen %d", opcode, plen);

	hci_req_sync_lock(hdev);
	skb = __hci_cmd_sync(hdev, opcode, plen, param, timeout);
	hci_req_sync_unlock(hdev);

	return skb;
}
EXPORT_SYMBOL(hci_cmd_sync);

/* This function requires the caller holds hdev->req_lock. */
struct sk_buff *__hci_cmd_sync_ev(struct hci_dev *hdev, u16 opcode, u32 plen,
				  const void *param, u8 event, u32 timeout)
{
	return __hci_cmd_sync_sk(hdev, opcode, plen, param, event, timeout,
				 NULL);
}
EXPORT_SYMBOL(__hci_cmd_sync_ev);

/* This function requires the caller holds hdev->req_lock. */
int __hci_cmd_sync_status_sk(struct hci_dev *hdev, u16 opcode, u32 plen,
			     const void *param, u8 event, u32 timeout,
			     struct sock *sk)
{
	struct sk_buff *skb;
	u8 status;

	skb = __hci_cmd_sync_sk(hdev, opcode, plen, param, event, timeout, sk);
	if (IS_ERR_OR_NULL(skb)) {
		bt_dev_err(hdev, "Opcode 0x%4x failed: %ld", opcode,
			   PTR_ERR(skb));
		return PTR_ERR(skb);
	}

	status = skb->data[0];

	kfree_skb(skb);

	return status;
}
EXPORT_SYMBOL(__hci_cmd_sync_status_sk);

int __hci_cmd_sync_status(struct hci_dev *hdev, u16 opcode, u32 plen,
			  const void *param, u32 timeout)
{
	return __hci_cmd_sync_status_sk(hdev, opcode, plen, param, 0, timeout,
					NULL);
}
EXPORT_SYMBOL(__hci_cmd_sync_status);

static void hci_cmd_sync_work(struct work_struct *work)
{
	struct hci_dev *hdev = container_of(work, struct hci_dev, cmd_sync_work);
	struct hci_cmd_sync_work_entry *entry;
	hci_cmd_sync_work_func_t func;
	hci_cmd_sync_work_destroy_t destroy;
	void *data;

	bt_dev_dbg(hdev, "");

	mutex_lock(&hdev->cmd_sync_work_lock);
	entry = list_first_entry(&hdev->cmd_sync_work_list,
				 struct hci_cmd_sync_work_entry, list);
	if (entry) {
		list_del(&entry->list);
		func = entry->func;
		data = entry->data;
		destroy = entry->destroy;
		kfree(entry);
	} else {
		func = NULL;
		data = NULL;
		destroy = NULL;
	}
	mutex_unlock(&hdev->cmd_sync_work_lock);

	if (func) {
		int err;

		hci_req_sync_lock(hdev);

		err = func(hdev, data);

		if (destroy)
			destroy(hdev, data, err);

		hci_req_sync_unlock(hdev);
	}
}

void hci_cmd_sync_init(struct hci_dev *hdev)
{
	INIT_WORK(&hdev->cmd_sync_work, hci_cmd_sync_work);
	INIT_LIST_HEAD(&hdev->cmd_sync_work_list);
	mutex_init(&hdev->cmd_sync_work_lock);
}

void hci_cmd_sync_clear(struct hci_dev *hdev)
{
	struct hci_cmd_sync_work_entry *entry, *tmp;

	cancel_work_sync(&hdev->cmd_sync_work);

	list_for_each_entry_safe(entry, tmp, &hdev->cmd_sync_work_list, list) {
		if (entry->destroy)
			entry->destroy(hdev, entry->data, -ECANCELED);

		list_del(&entry->list);
		kfree(entry);
	}
}

int hci_cmd_sync_queue(struct hci_dev *hdev, hci_cmd_sync_work_func_t func,
		       void *data, hci_cmd_sync_work_destroy_t destroy)
{
	struct hci_cmd_sync_work_entry *entry;

	entry = kmalloc(sizeof(*entry), GFP_KERNEL);
	if (!entry)
		return -ENOMEM;

	entry->func = func;
	entry->data = data;
	entry->destroy = destroy;

	mutex_lock(&hdev->cmd_sync_work_lock);
	list_add_tail(&entry->list, &hdev->cmd_sync_work_list);
	mutex_unlock(&hdev->cmd_sync_work_lock);

	queue_work(hdev->req_workqueue, &hdev->cmd_sync_work);

	return 0;
}
EXPORT_SYMBOL(hci_cmd_sync_queue);