pico hid bridge mode

hid/pico/src/ph_com_bridge.c

@@ -0,0 +1,84 @@
+/*****************************************************************************
+#                                                                            #
+#    KVMD - The main PiKVM daemon.                                           #
+#                                                                            #
+#    Copyright (C) 2018-2023  Maxim Devaev <mdevaev@gmail.com>               #
+#                                                                            #
+#    This program is free software: you can redistribute it and/or modify    #
+#    it under the terms of the GNU General Public License as published by    #
+#    the Free Software Foundation, either version 3 of the License, or       #
+#    (at your option) any later version.                                     #
+#                                                                            #
+#    This program is distributed in the hope that it will be useful,         #
+#    but WITHOUT ANY WARRANTY; without even the implied warranty of          #
+#    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the           #
+#    GNU General Public License for more details.                            #
+#                                                                            #
+#    You should have received a copy of the GNU General Public License       #
+#    along with this program.  If not, see <https://www.gnu.org/licenses/>.  #
+#                                                                            #
+*****************************************************************************/
+
+
+#include "ph_com_bridge.h"
+
+#include "pico/stdlib.h"
+
+#include "tusb.h"
+
+#include "ph_types.h"
+
+
+#define _TIMEOUT_US	100000
+
+
+static u8 _buf[8] = {0};
+static u8 _index = 0;
+static u64 _last_ts = 0;
+
+static void (*_data_cb)(const u8 *) = NULL;
+static void (*_timeout_cb)(void) = NULL;
+
+
+void ph_com_bridge_init(void (*data_cb)(const u8 *), void (*timeout_cb)(void)) {
+	_data_cb = data_cb;
+	_timeout_cb = timeout_cb;
+}
+
+void ph_com_bridge_task(void) {
+	if (!tud_cdc_connected()) {
+		tud_cdc_write_clear();
+		return;
+	}
+
+	if (tud_cdc_available() > 0) {
+		const s32 ch = tud_cdc_read_char();
+		if (ch < 0) {
+			goto no_data;
+		}
+		_buf[_index] = (u8)ch;
+		if (_index == 7) {
+			_data_cb(_buf);
+			_index = 0;
+		} else {
+			_last_ts = time_us_64();
+			++_index;
+		}
+		return;
+	}
+
+	no_data:
+	if (_index > 0) {
+		if (_last_ts + _TIMEOUT_US < time_us_64()) {
+			_timeout_cb();
+			_index = 0;
+		}
+	}
+}
+
+void ph_com_bridge_write(const u8 *data) {
+	if (tud_cdc_connected()) {
+		tud_cdc_write(data, 8);
+		tud_cdc_write_flush();
+	}
+}