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zephyr/drivers/bluetooth/hci/h5.c

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/* uart_h5.c - UART based Bluetooth driver */
/*
* Copyright (c) 2015-2016 Intel Corporation
*
* SPDX-License-Identifier: Apache-2.0
*/
#include <errno.h>
#include <stddef.h>
#include <zephyr/zephyr.h>
#include <zephyr/init.h>
#include <zephyr/drivers/uart.h>
#include <zephyr/sys/util.h>
#include <zephyr/sys/byteorder.h>
#include <zephyr/debug/stack.h>
#include <zephyr/sys/printk.h>
#include <string.h>
#include <zephyr/bluetooth/bluetooth.h>
#include <zephyr/bluetooth/hci.h>
#include <zephyr/drivers/bluetooth/hci_driver.h>
#define BT_DBG_ENABLED IS_ENABLED(CONFIG_BT_DEBUG_HCI_DRIVER)
#define LOG_MODULE_NAME bt_driver
#include "common/log.h"
#include "../util.h"
static K_KERNEL_STACK_DEFINE(tx_stack, 256);
static K_KERNEL_STACK_DEFINE(rx_stack, 256);
static struct k_thread tx_thread_data;
static struct k_thread rx_thread_data;
static struct k_work_delayable ack_work;
static struct k_work_delayable retx_work;
#define HCI_3WIRE_ACK_PKT 0x00
#define HCI_COMMAND_PKT 0x01
#define HCI_ACLDATA_PKT 0x02
#define HCI_SCODATA_PKT 0x03
#define HCI_EVENT_PKT 0x04
#define HCI_ISODATA_PKT 0x05
#define HCI_3WIRE_LINK_PKT 0x0f
#define HCI_VENDOR_PKT 0xff
static bool reliable_packet(uint8_t type)
{
switch (type) {
case HCI_COMMAND_PKT:
case HCI_ACLDATA_PKT:
case HCI_EVENT_PKT:
case HCI_ISODATA_PKT:
return true;
default:
return false;
}
}
/* FIXME: Correct timeout */
#define H5_RX_ACK_TIMEOUT K_MSEC(250)
#define H5_TX_ACK_TIMEOUT K_MSEC(250)
#define SLIP_DELIMITER 0xc0
#define SLIP_ESC 0xdb
#define SLIP_ESC_DELIM 0xdc
#define SLIP_ESC_ESC 0xdd
#define H5_RX_ESC 1
#define H5_TX_ACK_PEND 2
#define H5_HDR_SEQ(hdr) ((hdr)[0] & 0x07)
#define H5_HDR_ACK(hdr) (((hdr)[0] >> 3) & 0x07)
#define H5_HDR_CRC(hdr) (((hdr)[0] >> 6) & 0x01)
#define H5_HDR_RELIABLE(hdr) (((hdr)[0] >> 7) & 0x01)
#define H5_HDR_PKT_TYPE(hdr) ((hdr)[1] & 0x0f)
#define H5_HDR_LEN(hdr) ((((hdr)[1] >> 4) & 0x0f) + ((hdr)[2] << 4))
#define H5_SET_SEQ(hdr, seq) ((hdr)[0] |= (seq))
#define H5_SET_ACK(hdr, ack) ((hdr)[0] |= (ack) << 3)
#define H5_SET_RELIABLE(hdr) ((hdr)[0] |= 1 << 7)
#define H5_SET_TYPE(hdr, type) ((hdr)[1] |= type)
#define H5_SET_LEN(hdr, len) (((hdr)[1] |= ((len) & 0x0f) << 4), \
((hdr)[2] |= (len) >> 4))
static struct h5 {
struct net_buf *rx_buf;
struct k_fifo tx_queue;
struct k_fifo rx_queue;
struct k_fifo unack_queue;
uint8_t tx_win;
uint8_t tx_ack;
uint8_t tx_seq;
uint8_t rx_ack;
enum {
UNINIT,
INIT,
ACTIVE,
} link_state;
enum {
START,
HEADER,
PAYLOAD,
END,
} rx_state;
} h5;
static uint8_t unack_queue_len;
static const uint8_t sync_req[] = { 0x01, 0x7e };
static const uint8_t sync_rsp[] = { 0x02, 0x7d };
/* Third byte may change */
static uint8_t conf_req[3] = { 0x03, 0xfc };
static const uint8_t conf_rsp[] = { 0x04, 0x7b };
/* H5 signal buffers pool */
#define MAX_SIG_LEN 3
#define SIGNAL_COUNT 2
#define SIG_BUF_SIZE (BT_BUF_RESERVE + MAX_SIG_LEN)
NET_BUF_POOL_DEFINE(h5_pool, SIGNAL_COUNT, SIG_BUF_SIZE, 0, NULL);
static const struct device *h5_dev;
static void h5_reset_rx(void)
{
if (h5.rx_buf) {
net_buf_unref(h5.rx_buf);
h5.rx_buf = NULL;
}
h5.rx_state = START;
}
static int h5_unslip_byte(uint8_t *byte)
{
int count;
if (*byte != SLIP_ESC) {
return 0;
}
do {
count = uart_fifo_read(h5_dev, byte, sizeof(*byte));
} while (!count);
switch (*byte) {
case SLIP_ESC_DELIM:
*byte = SLIP_DELIMITER;
break;
case SLIP_ESC_ESC:
*byte = SLIP_ESC;
break;
default:
BT_ERR("Invalid escape byte %x\n", *byte);
return -EIO;
}
return 0;
}
static void process_unack(void)
{
uint8_t next_seq = h5.tx_seq;
uint8_t number_removed = unack_queue_len;
if (!unack_queue_len) {
return;
}
BT_DBG("rx_ack %u tx_ack %u tx_seq %u unack_queue_len %u",
h5.rx_ack, h5.tx_ack, h5.tx_seq, unack_queue_len);
while (unack_queue_len > 0) {
if (next_seq == h5.rx_ack) {
/* Next sequence number is the same as last received
* ack number
*/
break;
}
number_removed--;
/* Similar to (n - 1) % 8 with unsigned conversion */
next_seq = (next_seq - 1) & 0x07;
}
if (next_seq != h5.rx_ack) {
BT_ERR("Wrong sequence: rx_ack %u tx_seq %u next_seq %u",
h5.rx_ack, h5.tx_seq, next_seq);
}
BT_DBG("Need to remove %u packet from the queue", number_removed);
while (number_removed) {
struct net_buf *buf = net_buf_get(&h5.unack_queue, K_NO_WAIT);
if (!buf) {
BT_ERR("Unack queue is empty");
break;
}
/* TODO: print or do something with packet */
BT_DBG("Remove buf from the unack_queue");
net_buf_unref(buf);
unack_queue_len--;
number_removed--;
}
}
static void h5_print_header(const uint8_t *hdr, const char *str)
{
if (H5_HDR_RELIABLE(hdr)) {
BT_DBG("%s REL: seq %u ack %u crc %u type %u len %u",
str, H5_HDR_SEQ(hdr), H5_HDR_ACK(hdr),
H5_HDR_CRC(hdr), H5_HDR_PKT_TYPE(hdr),
H5_HDR_LEN(hdr));
} else {
BT_DBG("%s UNREL: ack %u crc %u type %u len %u",
str, H5_HDR_ACK(hdr), H5_HDR_CRC(hdr),
H5_HDR_PKT_TYPE(hdr), H5_HDR_LEN(hdr));
}
}
#if defined(CONFIG_BT_DEBUG_HCI_DRIVER)
static void hexdump(const char *str, const uint8_t *packet, size_t length)
{
int n = 0;
if (!length) {
printk("%s zero-length signal packet\n", str);
return;
}
while (length--) {
if (n % 16 == 0) {
printk("%s %08X ", str, n);
}
printk("%02X ", *packet++);
n++;
if (n % 8 == 0) {
if (n % 16 == 0) {
printk("\n");
} else {
printk(" ");
}
}
}
if (n % 16) {
printk("\n");
}
}
#else
#define hexdump(str, packet, length)
#endif
static uint8_t h5_slip_byte(uint8_t byte)
{
switch (byte) {
case SLIP_DELIMITER:
uart_poll_out(h5_dev, SLIP_ESC);
uart_poll_out(h5_dev, SLIP_ESC_DELIM);
return 2;
case SLIP_ESC:
uart_poll_out(h5_dev, SLIP_ESC);
uart_poll_out(h5_dev, SLIP_ESC_ESC);
return 2;
default:
uart_poll_out(h5_dev, byte);
return 1;
}
}
static void h5_send(const uint8_t *payload, uint8_t type, int len)
{
uint8_t hdr[4];
int i;
hexdump("<= ", payload, len);
(void)memset(hdr, 0, sizeof(hdr));
/* Set ACK for outgoing packet and stop delayed work */
H5_SET_ACK(hdr, h5.tx_ack);
/* If cancel fails we may ack the same seq number twice, this is OK. */
(void)k_work_cancel_delayable(&ack_work);
if (reliable_packet(type)) {
H5_SET_RELIABLE(hdr);
H5_SET_SEQ(hdr, h5.tx_seq);
h5.tx_seq = (h5.tx_seq + 1) % 8;
}
H5_SET_TYPE(hdr, type);
H5_SET_LEN(hdr, len);
/* Calculate CRC */
hdr[3] = ~((hdr[0] + hdr[1] + hdr[2]) & 0xff);
h5_print_header(hdr, "TX: <");
uart_poll_out(h5_dev, SLIP_DELIMITER);
for (i = 0; i < 4; i++) {
h5_slip_byte(hdr[i]);
}
for (i = 0; i < len; i++) {
h5_slip_byte(payload[i]);
}
uart_poll_out(h5_dev, SLIP_DELIMITER);
}
/* Delayed work taking care about retransmitting packets */
static void retx_timeout(struct k_work *work)
{
ARG_UNUSED(work);
BT_DBG("unack_queue_len %u", unack_queue_len);
if (unack_queue_len) {
struct k_fifo tmp_queue;
struct net_buf *buf;
k_fifo_init(&tmp_queue);
/* Queue to temporary queue */
while ((buf = net_buf_get(&h5.tx_queue, K_NO_WAIT))) {
net_buf_put(&tmp_queue, buf);
}
/* Queue unack packets to the beginning of the queue */
while ((buf = net_buf_get(&h5.unack_queue, K_NO_WAIT))) {
/* include also packet type */
net_buf_push(buf, sizeof(uint8_t));
net_buf_put(&h5.tx_queue, buf);
h5.tx_seq = (h5.tx_seq - 1) & 0x07;
unack_queue_len--;
}
/* Queue saved packets from temp queue */
while ((buf = net_buf_get(&tmp_queue, K_NO_WAIT))) {
net_buf_put(&h5.tx_queue, buf);
}
}
}
static void ack_timeout(struct k_work *work)
{
ARG_UNUSED(work);
BT_DBG("");
h5_send(NULL, HCI_3WIRE_ACK_PKT, 0);
}
static void h5_process_complete_packet(uint8_t *hdr)
{
struct net_buf *buf;
BT_DBG("");
/* rx_ack should be in every packet */
h5.rx_ack = H5_HDR_ACK(hdr);
if (reliable_packet(H5_HDR_PKT_TYPE(hdr))) {
/* For reliable packet increment next transmit ack number */
h5.tx_ack = (h5.tx_ack + 1) % 8;
/* Submit delayed work to ack the packet */
k_work_reschedule(&ack_work, H5_RX_ACK_TIMEOUT);
}
h5_print_header(hdr, "RX: >");
process_unack();
buf = h5.rx_buf;
h5.rx_buf = NULL;
switch (H5_HDR_PKT_TYPE(hdr)) {
case HCI_3WIRE_ACK_PKT:
net_buf_unref(buf);
break;
case HCI_3WIRE_LINK_PKT:
net_buf_put(&h5.rx_queue, buf);
break;
case HCI_EVENT_PKT:
case HCI_ACLDATA_PKT:
case HCI_ISODATA_PKT:
hexdump("=> ", buf->data, buf->len);
bt_recv(buf);
break;
}
}
static inline struct net_buf *get_evt_buf(uint8_t evt)
{
return bt_buf_get_evt(evt, false, K_NO_WAIT);
}
static void bt_uart_isr(const struct device *unused, void *user_data)
{
static int remaining;
uint8_t byte;
int ret;
static uint8_t hdr[4];
size_t buf_tailroom;
ARG_UNUSED(unused);
ARG_UNUSED(user_data);
while (uart_irq_update(h5_dev) &&
uart_irq_is_pending(h5_dev)) {
if (!uart_irq_rx_ready(h5_dev)) {
if (uart_irq_tx_ready(h5_dev)) {
BT_DBG("transmit ready");
} else {
BT_DBG("spurious interrupt");
}
/* Only the UART RX path is interrupt-enabled */
break;
}
ret = uart_fifo_read(h5_dev, &byte, sizeof(byte));
if (!ret) {
continue;
}
switch (h5.rx_state) {
case START:
if (byte == SLIP_DELIMITER) {
h5.rx_state = HEADER;
remaining = sizeof(hdr);
}
break;
case HEADER:
/* In a case we confuse ending slip delimiter
* with starting one.
*/
if (byte == SLIP_DELIMITER) {
remaining = sizeof(hdr);
continue;
}
if (h5_unslip_byte(&byte) < 0) {
h5_reset_rx();
continue;
}
memcpy(&hdr[sizeof(hdr) - remaining], &byte, 1);
remaining--;
if (remaining) {
break;
}
remaining = H5_HDR_LEN(hdr);
switch (H5_HDR_PKT_TYPE(hdr)) {
case HCI_EVENT_PKT:
/* The buffer is allocated only once we know
* the exact event type.
*/
h5.rx_state = PAYLOAD;
break;
case HCI_ACLDATA_PKT:
h5.rx_buf = bt_buf_get_rx(BT_BUF_ACL_IN,
K_NO_WAIT);
if (!h5.rx_buf) {
BT_WARN("No available data buffers");
h5_reset_rx();
continue;
}
h5.rx_state = PAYLOAD;
break;
case HCI_ISODATA_PKT:
h5.rx_buf = bt_buf_get_rx(BT_BUF_ISO_IN,
K_NO_WAIT);
if (!h5.rx_buf) {
BT_WARN("No available data buffers");
h5_reset_rx();
continue;
}
h5.rx_state = PAYLOAD;
break;
case HCI_3WIRE_LINK_PKT:
case HCI_3WIRE_ACK_PKT:
h5.rx_buf = net_buf_alloc(&h5_pool, K_NO_WAIT);
if (!h5.rx_buf) {
BT_WARN("No available signal buffers");
h5_reset_rx();
continue;
}
h5.rx_state = PAYLOAD;
break;
default:
BT_ERR("Wrong packet type %u",
H5_HDR_PKT_TYPE(hdr));
h5.rx_state = END;
break;
}
if (!remaining) {
h5.rx_state = END;
}
break;
case PAYLOAD:
if (h5_unslip_byte(&byte) < 0) {
h5_reset_rx();
continue;
}
/* Allocate HCI event buffer now that we know the
* exact event type.
*/
if (!h5.rx_buf) {
h5.rx_buf = get_evt_buf(byte);
if (!h5.rx_buf) {
BT_WARN("No available event buffers");
h5_reset_rx();
continue;
}
}
buf_tailroom = net_buf_tailroom(h5.rx_buf);
if (buf_tailroom < sizeof(byte)) {
BT_ERR("Not enough space in buffer %zu/%zu",
sizeof(byte), buf_tailroom);
h5_reset_rx();
break;
}
net_buf_add_mem(h5.rx_buf, &byte, sizeof(byte));
remaining--;
if (!remaining) {
h5.rx_state = END;
}
break;
case END:
if (byte != SLIP_DELIMITER) {
BT_ERR("Missing ending SLIP_DELIMITER");
h5_reset_rx();
break;
}
BT_DBG("Received full packet: type %u",
H5_HDR_PKT_TYPE(hdr));
/* Check when full packet is received, it can be done
* when parsing packet header but we need to receive
* full packet anyway to clear UART.
*/
if (H5_HDR_RELIABLE(hdr) &&
H5_HDR_SEQ(hdr) != h5.tx_ack) {
BT_ERR("Seq expected %u got %u. Drop packet",
h5.tx_ack, H5_HDR_SEQ(hdr));
h5_reset_rx();
break;
}
h5_process_complete_packet(hdr);
h5.rx_state = START;
break;
}
}
}
static uint8_t h5_get_type(struct net_buf *buf)
{
return net_buf_pull_u8(buf);
}
static int h5_queue(struct net_buf *buf)
{
uint8_t type;
BT_DBG("buf %p type %u len %u", buf, bt_buf_get_type(buf), buf->len);
switch (bt_buf_get_type(buf)) {
case BT_BUF_CMD:
type = HCI_COMMAND_PKT;
break;
case BT_BUF_ACL_OUT:
type = HCI_ACLDATA_PKT;
break;
case BT_BUF_ISO_OUT:
type = HCI_ISODATA_PKT;
break;
default:
BT_ERR("Unknown packet type %u", bt_buf_get_type(buf));
return -1;
}
memcpy(net_buf_push(buf, sizeof(type)), &type, sizeof(type));
net_buf_put(&h5.tx_queue, buf);
return 0;
}
static void tx_thread(void)
{
BT_DBG("");
/* FIXME: make periodic sending */
h5_send(sync_req, HCI_3WIRE_LINK_PKT, sizeof(sync_req));
while (true) {
struct net_buf *buf;
uint8_t type;
BT_DBG("link_state %u", h5.link_state);
switch (h5.link_state) {
case UNINIT:
/* FIXME: send sync */
k_sleep(K_MSEC(100));
break;
case INIT:
/* FIXME: send conf */
k_sleep(K_MSEC(100));
break;
case ACTIVE:
buf = net_buf_get(&h5.tx_queue, K_FOREVER);
type = h5_get_type(buf);
h5_send(buf->data, type, buf->len);
/* buf is dequeued from tx_queue and queued to unack
* queue.
*/
net_buf_put(&h5.unack_queue, buf);
unack_queue_len++;
k_work_reschedule(&retx_work, H5_TX_ACK_TIMEOUT);
break;
}
}
}
static void h5_set_txwin(uint8_t *conf)
{
conf[2] = h5.tx_win & 0x07;
}
static void rx_thread(void)
{
BT_DBG("");
while (true) {
struct net_buf *buf;
buf = net_buf_get(&h5.rx_queue, K_FOREVER);
hexdump("=> ", buf->data, buf->len);
if (!memcmp(buf->data, sync_req, sizeof(sync_req))) {
if (h5.link_state == ACTIVE) {
/* TODO Reset H5 */
}
h5_send(sync_rsp, HCI_3WIRE_LINK_PKT, sizeof(sync_rsp));
} else if (!memcmp(buf->data, sync_rsp, sizeof(sync_rsp))) {
if (h5.link_state == ACTIVE) {
/* TODO Reset H5 */
}
h5.link_state = INIT;
h5_set_txwin(conf_req);
h5_send(conf_req, HCI_3WIRE_LINK_PKT, sizeof(conf_req));
} else if (!memcmp(buf->data, conf_req, 2)) {
/*
* The Host sends Config Response messages without a
* Configuration Field.
*/
h5_send(conf_rsp, HCI_3WIRE_LINK_PKT, sizeof(conf_rsp));
/* Then send Config Request with Configuration Field */
h5_set_txwin(conf_req);
h5_send(conf_req, HCI_3WIRE_LINK_PKT, sizeof(conf_req));
} else if (!memcmp(buf->data, conf_rsp, 2)) {
h5.link_state = ACTIVE;
if (buf->len > 2) {
/* Configuration field present */
h5.tx_win = (buf->data[2] & 0x07);
}
BT_DBG("Finished H5 configuration, tx_win %u",
h5.tx_win);
} else {
BT_ERR("Not handled yet %x %x",
buf->data[0], buf->data[1]);
}
net_buf_unref(buf);
/* Make sure we don't hog the CPU if the rx_queue never
* gets empty.
*/
k_yield();
}
}
static void h5_init(void)
{
BT_DBG("");
h5.link_state = UNINIT;
h5.rx_state = START;
h5.tx_win = 4U;
/* TX thread */
k_fifo_init(&h5.tx_queue);
k_thread_create(&tx_thread_data, tx_stack,
K_KERNEL_STACK_SIZEOF(tx_stack),
(k_thread_entry_t)tx_thread, NULL, NULL, NULL,
K_PRIO_COOP(CONFIG_BT_HCI_TX_PRIO),
0, K_NO_WAIT);
k_thread_name_set(&tx_thread_data, "tx_thread");
k_fifo_init(&h5.rx_queue);
k_thread_create(&rx_thread_data, rx_stack,
K_KERNEL_STACK_SIZEOF(rx_stack),
(k_thread_entry_t)rx_thread, NULL, NULL, NULL,
K_PRIO_COOP(CONFIG_BT_RX_PRIO),
0, K_NO_WAIT);
k_thread_name_set(&rx_thread_data, "rx_thread");
/* Unack queue */
k_fifo_init(&h5.unack_queue);
/* Init delayed work */
k_work_init_delayable(&ack_work, ack_timeout);
k_work_init_delayable(&retx_work, retx_timeout);
}
static int h5_open(void)
{
BT_DBG("");
uart_irq_rx_disable(h5_dev);
uart_irq_tx_disable(h5_dev);
bt_uart_drain(h5_dev);
uart_irq_callback_set(h5_dev, bt_uart_isr);
h5_init();
uart_irq_rx_enable(h5_dev);
return 0;
}
static const struct bt_hci_driver drv = {
.name = "H:5",
.bus = BT_HCI_DRIVER_BUS_UART,
.open = h5_open,
.send = h5_queue,
};
static int bt_uart_init(const struct device *unused)
{
ARG_UNUSED(unused);
h5_dev = DEVICE_DT_GET(DT_CHOSEN(zephyr_bt_uart));
if (!device_is_ready(h5_dev)) {
return -EINVAL;
}
bt_hci_driver_register(&drv);
return 0;
}
SYS_INIT(bt_uart_init, POST_KERNEL, CONFIG_KERNEL_INIT_PRIORITY_DEVICE);
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