zephyr/net/bluetooth/hci_core.c

/* hci_core.c - HCI core Bluetooth handling */

/*
 * Copyright (c) 2015 Intel Corporation
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * 1) Redistributions of source code must retain the above copyright notice,
 * this list of conditions and the following disclaimer.
 *
 * 2) Redistributions in binary form must reproduce the above copyright notice,
 * this list of conditions and the following disclaimer in the documentation
 * and/or other materials provided with the distribution.
 *
 * 3) Neither the name of Intel Corporation nor the names of its contributors
 * may be used to endorse or promote products derived from this software without
 * specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

#include <nanokernel.h>
#include <toolchain.h>
#include <string.h>
#include <errno.h>
#include <misc/byteorder.h>

#include <bluetooth/hci.h>
#include <bluetooth/bluetooth.h>

/* Stacks for the fibers */
#define RX_STACK_SIZE	1024
#define CMD_STACK_SIZE	256
static char rx_fiber_stack[RX_STACK_SIZE];
static char cmd_fiber_stack[CMD_STACK_SIZE];

/* Available (free) buffers queue */
#define NUM_BUFS		5
static struct bt_buf		buffers[NUM_BUFS];
static struct nano_fifo		free_bufs;

/* State tracking for the local Bluetooth controller */
static struct bt_dev {
	/* Number of commands controller can accept */
	uint8_t			ncmd;
	struct nano_sem		ncmd_sem;

	/* Last sent HCI command */
	struct bt_buf		*sent_cmd;

	/* Queue for incoming HCI events & ACL data */
	struct nano_fifo	rx_queue;

	/* Queue for outgoing HCI commands */
	struct nano_fifo	cmd_queue;

	/* Registered HCI driver */
	struct bt_driver	*drv;
} dev;

struct bt_buf *bt_buf_get_reserve(size_t reserve_head)
{
	struct bt_buf *buf;

	buf = nano_fifo_get(&free_bufs);
	if (!buf) {
		BT_ERR("Failed to get free buffer\n");
		return NULL;
	}

	buf->data = buf->buf + reserve_head;
	buf->len = 0;
	buf->sync = NULL;

	BT_DBG("buf %p reserve %u\n", buf, reserve_head);

	return buf;
}

struct bt_buf *bt_buf_get(void)
{
	return bt_buf_get_reserve(0);
}

void bt_buf_put(struct bt_buf *buf)
{
	BT_DBG("buf %p\n", buf);

	nano_fifo_put(&free_bufs, buf);
}

uint8_t *bt_buf_add(struct bt_buf *buf, size_t len)
{
	uint8_t *tail = buf->data + buf->len;
	buf->len += len;
	return tail;
}

uint8_t *bt_buf_push(struct bt_buf *buf, size_t len)
{
	buf->data -= len;
	buf->len += len;
	return buf->data;
}

uint8_t *bt_buf_pull(struct bt_buf *buf, size_t len)
{
	buf->len -= len;
	return buf->data += len;
}

size_t bt_buf_headroom(struct bt_buf *buf)
{
	return buf->data - buf->buf;
}

size_t bt_buf_tailroom(struct bt_buf *buf)
{
	return BT_BUF_MAX_DATA - bt_buf_headroom(buf) - buf->len;
}

static struct bt_buf *bt_hci_cmd_create(uint16_t opcode, uint8_t param_len)
{
	struct bt_hci_cmd_hdr *hdr;
	struct bt_buf *buf;

	BT_DBG("opcode %x param_len %u\n", opcode, param_len);

	buf = bt_buf_get_reserve(dev.drv->head_reserve);
	if (!buf) {
		BT_ERR("Cannot get free buffer\n");
		return NULL;
	}

	BT_DBG("buf %p\n", buf);

	buf->type = BT_CMD;
	buf->opcode = opcode;
	buf->sync = NULL;

	hdr = (void *)bt_buf_add(buf, sizeof(*hdr));
	hdr->opcode = sys_cpu_to_le16(opcode);
	hdr->param_len = param_len;

	return buf;
}

static int bt_hci_cmd_send(uint16_t opcode, struct bt_buf *buf)
{
	if (!buf) {
		buf = bt_hci_cmd_create(opcode, 0);
		if (!buf)
			return -ENOBUFS;
	}

	BT_DBG("opcode %x len %u\n", opcode, buf->len);

	nano_fifo_put(&dev.cmd_queue, buf);

	return 0;
}

static void hci_acl(struct bt_buf *buf)
{
	BT_DBG("\n");
}

/* HCI event processing */

static void hci_reset_complete(struct bt_buf *buf)
{
	uint8_t status = buf->data[0];

	BT_DBG("status %u\n", status);

	if (status)
		return;
}

static void hci_cmd_done(uint16_t opcode)
{
	struct bt_buf *sent = dev.sent_cmd;

	if (dev.sent_cmd->opcode != opcode) {
		BT_ERR("Unexpected completion of opcode %x\n", opcode);
		return;
	}

	dev.sent_cmd = NULL;

	bt_buf_put(sent);
}

static void hci_cmd_complete(struct bt_buf *buf)
{
	struct hci_evt_cmd_complete *evt = (void *)buf->data;
	uint16_t opcode = sys_le16_to_cpu(evt->opcode);

	BT_DBG("opcode %x\n", opcode);

	bt_buf_pull(buf, sizeof(*evt));

	switch (opcode) {
	case BT_HCI_OP_RESET:
		hci_reset_complete(buf);
		break;
	default:
		BT_ERR("Unknown opcode %x\n", opcode);
		break;
	}

	hci_cmd_done(opcode);

	if (evt->ncmd && !dev.ncmd) {
		/* Allow next command to be sent */
		dev.ncmd = 1;
		nano_fiber_sem_give(&dev.ncmd_sem);
	}
}

static void hci_cmd_status(struct bt_buf *buf)
{
	struct bt_hci_evt_cmd_status *evt = (void *)buf->data;
	uint16_t opcode = sys_le16_to_cpu(evt->opcode);

	BT_DBG("opcode %x\n", opcode);

	bt_buf_pull(buf, sizeof(*evt));

	switch (opcode) {
	default:
		BT_ERR("Unknown opcode %x", opcode);
		break;
	}

	hci_cmd_done(opcode);

	if (evt->ncmd && !dev.ncmd) {
		/* Allow next command to be sent */
		dev.ncmd = 1;
		nano_fiber_sem_give(&dev.ncmd_sem);
	}
}

static void hci_event(struct bt_buf *buf)
{
	struct bt_hci_evt_hdr *hdr = (void *)buf->data;

	BT_DBG("event %u\n", hdr->evt);

	bt_buf_pull(buf, sizeof(*hdr));

	switch (hdr->evt) {
	case BT_HCI_EVT_CMD_COMPLETE:
		hci_cmd_complete(buf);
		break;
	case BT_HCI_EVT_CMD_STATUS:
		hci_cmd_status(buf);
		break;
	default:
		BT_ERR("Unknown event %u\n", hdr->evt);
		break;
	}
}

static void hci_receive_packet(struct bt_buf *buf)
{
	BT_DBG("buf %p type %u\n", buf, buf->type);

	switch (buf->type) {
	case BT_ACL:
		hci_acl(buf);
		break;
	case BT_EVT:
		hci_event(buf);
		break;
	default:
		return;
	}
}

static void hci_cmd_fiber(void)
{
	struct bt_driver *drv = dev.drv;

	BT_DBG("\n");

	while (1) {
		struct bt_buf *buf;

		/* Wait until ncmd > 0 */
		nano_fiber_sem_take_wait(&dev.ncmd_sem);

		/* Get next command - wait if necessary */
		buf = nano_fifo_get_wait(&dev.cmd_queue);
		dev.ncmd = 0;

		BT_DBG("Sending command (buf %p) to driver\n", buf);

		drv->send(buf);
		dev.sent_cmd = buf;
	}
}

static void hci_rx_fiber(void)
{
	struct bt_buf *buf;

	BT_DBG("\n");

	while (1) {
		buf = nano_fifo_get_wait(&dev.rx_queue);

		hci_receive_packet(buf);
		bt_buf_put(buf);
	}
}

static int hci_init(void)
{
	/* Send HCI_RESET */
	bt_hci_cmd_send(BT_HCI_OP_RESET, NULL);

	return 0;
}

/* Interface to HCI driver layer */

void bt_recv(struct bt_buf *buf)
{
	nano_fifo_put(&dev.rx_queue, buf);
}

int bt_driver_register(struct bt_driver *drv)
{
	if (dev.drv)
		return -EALREADY;

	if (!drv->open || !drv->send)
		return -EINVAL;

	dev.drv = drv;

	return 0;
}

void bt_driver_unregister(struct bt_driver *drv)
{
	dev.drv = NULL;
}

/* fibers, fifos and semaphores initialization */

static void cmd_queue_init(void)
{
	nano_fifo_init(&dev.cmd_queue);
	nano_sem_init(&dev.ncmd_sem);

	/* Give cmd_sem allowing to send first HCI_Reset cmd */
	dev.ncmd = 1;
	nano_task_sem_give(&dev.ncmd_sem);

	fiber_start(cmd_fiber_stack, CMD_STACK_SIZE,
		    (nano_fiber_entry_t) hci_cmd_fiber, 0, 0, 7, 0);
}

static void rx_queue_init(void)
{
	nano_fifo_init(&dev.rx_queue);

	fiber_start(rx_fiber_stack, RX_STACK_SIZE,
		    (nano_fiber_entry_t) hci_rx_fiber, 0, 0, 7, 0);
}

static void free_queue_init(void)
{
	nano_fifo_init(&free_bufs);

	for (int i = 0; i < NUM_BUFS; i++)
		nano_fifo_put(&free_bufs, &buffers[i]);
}

int bt_init(void)
{
	struct bt_driver *drv = dev.drv;
	int err;

	if (!drv)
		return -ENODEV;

	free_queue_init();
	cmd_queue_init();
	rx_queue_init();

	err = drv->open();
	if (err)
		return err;

	return hci_init();
}