rpi4-osdev/part7-bluetooth/kernel.c

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6.3 KiB
C
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#include "io.h"
#include "bt.h"
#include "fb.h"
#define MAX_MSG_LEN 50
#define MAX_READ_RUN 100
unsigned char data_buf[MAX_MSG_LEN];
unsigned int data_len;
unsigned int messages_received = 0;
unsigned int poll_state = 0;
enum {
LE_EVENT_CODE = 0x3e,
LE_CONNECT_CODE = 0x01,
LE_ADREPORT_CODE = 0x02,
HCI_ACL_PKT = 0x02,
HCI_EVENT_PKT = 0x04
};
unsigned int got_echo_sid = 0;
unsigned int got_echo_name = 0;
unsigned char echo_addr[6];
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unsigned int connected = 0;
unsigned int connection_handle = 0;
int memcmp(const char *str1, const char *str2, int count) {
const char *s1 = (const char*)str1;
const char *s2 = (const char*)str2;
while (count-- > 0) {
if (*s1++ != *s2++) return s1[-1] < s2[-1] ? -1 : 1;
}
return 0;
}
void hci_poll2(unsigned char byte)
{
switch (poll_state) {
case 0:
if (byte != HCI_EVENT_PKT) poll_state = 0;
else poll_state = 1;
break;
case 1:
if (byte != LE_EVENT_CODE) poll_state = 0;
else poll_state = 2;
break;
case 2:
if (byte > MAX_MSG_LEN) poll_state = 0;
else {
poll_state = 3;
data_len = byte;
}
break;
default:
data_buf[poll_state - 3] = byte;
if (poll_state == data_len + 3 - 1) {
messages_received++;
poll_state = 0;
} else poll_state++;
}
}
unsigned char *hci_poll()
{
unsigned int goal = messages_received + 1;
if (bt_isReadByteReady()) {
unsigned int run = 0;
while (run < MAX_READ_RUN && messages_received < goal && bt_isReadByteReady()) {
unsigned char byte = bt_readByte();
hci_poll2(byte);
run++;
}
if (run == MAX_READ_RUN) return 0;
else return data_buf;
}
return 0;
}
void bt_search(void) {
unsigned char *buf;
while ( (buf = hci_poll()) ) {
if (data_len >= 2) {
if (buf[0] == LE_ADREPORT_CODE) {
if (buf[1] == 1) { // num_reports
if (buf[2] == 0) { // event_type
int bufindex = 0;
unsigned char ad_len = buf[11];
for (int c=9;c>=4;c--) echo_addr[9-c] = buf[bufindex + c]; // save the mac address
bufindex += 11;
got_echo_sid = 0; got_echo_name = 0; // Reset the search state machine
do {
ad_len = buf[bufindex];
unsigned char ad_type = buf[bufindex + 1];
bufindex += 2;
if (ad_len >= 2) {
if (ad_type == 0x03) {
unsigned int sid = buf[bufindex] | (buf[bufindex + 1] << 8);
if (sid == 0xEC00) {
got_echo_sid = 1;
debugstr("got sid... ");
}
} else if (ad_type == 0x09) {
char remote_name[ad_len - 1];
unsigned int d=0;
while (d<ad_len - 1) {
remote_name[d] = buf[bufindex + d];
d++;
}
if (!memcmp(remote_name,"echo",4)) {
got_echo_name = 1;
debugstr("got name... ");
}
}
}
bufindex += ad_len - 1;
} while (bufindex < data_len);
}
}
}
}
}
}
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void bt_conn()
{
unsigned char *buf;
while ( (buf = hci_poll()) ) {
if (data_len >= 2) {
if (buf[0] == LE_CONNECT_CODE && !connected) {
connected = !buf[1];
debughex(connected); debugstr(" ");
connection_handle = buf[2] | (buf[3] << 8);
debughex(connection_handle); debugstr(" ");
}
}
}
}
void acl_poll()
{
while (bt_isReadByteReady()) {
unsigned char byte = bt_readByte();
if (byte == HCI_EVENT_PKT) {
bt_waitReadByte(); // opcode
unsigned char length = bt_waitReadByte();
for (int i=0;i<length;i++) bt_waitReadByte();
} else if (byte == HCI_ACL_PKT) {
bt_waitReadByte(); // handle1
bt_waitReadByte(); // handle2
unsigned char h1 = bt_waitReadByte();
unsigned char h2 = bt_waitReadByte();
unsigned int dlen = h1 | (h2 << 8);
unsigned char data[dlen];
if (dlen > 7) {
for (int i=0;i<dlen;i++) data[i] = bt_waitReadByte();
unsigned int length = data[0] | (data[1] << 8);
unsigned int channel = data[2] | (data[3] << 8);
unsigned char opcode = data[4];
if (length == 4 && opcode == 0x1b) {
if (channel == 4 && data[5] == 0x2a && data[6] == 0x00) {
debugcrlf();
debugstr("Got ACL packet... ");
debugch(data[7]);
}
}
}
}
}
}
void run_search(void) {
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// Start scanning
debugstr("Setting event mask... ");
setLEeventmask(0xff);
debugstr("Starting scanning... ");
startActiveScanning();
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// Search for the echo
debugstr("Waiting...");
debugcrlf();
while (!(got_echo_sid && got_echo_name)) bt_search();
stopScanning();
for (int c=0;c<=5;c++) debugch(echo_addr[c]);
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debugcrlf();
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// Connecting to echo
debugstr("Connecting to echo: ");
connect(echo_addr);
while (!connected) bt_conn();
debugstr("Connected!");
debugcrlf();
// Get the characteristic value
debugstr("Sending read request: ");
debughex(connection_handle); debugcrlf();
sendACLsubscribe(connection_handle);
// Enter an infinite loop
debugstr("Going loopy...");
while (1) {
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acl_poll();
uart_update();
}
}
void run_eddystone(void) {
// Start advertising
debugstr("Setting event mask... ");
setLEeventmask(0xff);
debugstr("Starting advertsing... ");
startActiveAdvertising();
// Enter an infinite loop
debugstr("Going loopy...");
while (1) {
uart_update();
}
}
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void main()
{
fb_init();
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uart_init();
bt_init();
debugstr("Initialising Bluetooth: ");
debugstr(">> reset: ");
bt_reset();
debugstr(">> firmware load: ");
bt_loadfirmware();
debugstr(">> set baud: ");
bt_setbaud();
debugstr(">> set bdaddr: ");
bt_setbdaddr();
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// Print the BD_ADDR
unsigned char local_addr[6];
bt_getbdaddr(local_addr);
for (int c=5;c>=0;c--) debugch(local_addr[c]);
debugcrlf();
// Test out the scanning
run_search();
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}