From 242b80c63ffff022172755da35fb4767d5f837c2 Mon Sep 17 00:00:00 2001
From: Ryan <fauxpark@gmail.com>
Date: Mon, 30 Jan 2023 18:47:50 +1100
Subject: Move MIDI code out of tmk_core (#19704)

---
 quantum/midi/qmk_midi.c | 135 ++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 135 insertions(+)
 create mode 100644 quantum/midi/qmk_midi.c

(limited to 'quantum/midi/qmk_midi.c')

diff --git a/quantum/midi/qmk_midi.c b/quantum/midi/qmk_midi.c
new file mode 100644
index 0000000000..f6a5d92281
--- /dev/null
+++ b/quantum/midi/qmk_midi.c
@@ -0,0 +1,135 @@
+#include <LUFA/Drivers/USB/USB.h>
+#include "qmk_midi.h"
+#include "sysex_tools.h"
+#include "midi.h"
+#include "usb_descriptor.h"
+#include "process_midi.h"
+
+/*******************************************************************************
+ * MIDI
+ ******************************************************************************/
+
+MidiDevice midi_device;
+
+#define SYSEX_START_OR_CONT 0x40
+#define SYSEX_ENDS_IN_1 0x50
+#define SYSEX_ENDS_IN_2 0x60
+#define SYSEX_ENDS_IN_3 0x70
+
+#define SYS_COMMON_1 0x50
+#define SYS_COMMON_2 0x20
+#define SYS_COMMON_3 0x30
+
+static void usb_send_func(MidiDevice* device, uint16_t cnt, uint8_t byte0, uint8_t byte1, uint8_t byte2) {
+    MIDI_EventPacket_t event;
+    event.Data1 = byte0;
+    event.Data2 = byte1;
+    event.Data3 = byte2;
+
+    uint8_t cable = 0;
+
+    // if the length is undefined we assume it is a SYSEX message
+    if (midi_packet_length(byte0) == UNDEFINED) {
+        switch (cnt) {
+            case 3:
+                if (byte2 == SYSEX_END)
+                    event.Event = MIDI_EVENT(cable, SYSEX_ENDS_IN_3);
+                else
+                    event.Event = MIDI_EVENT(cable, SYSEX_START_OR_CONT);
+                break;
+            case 2:
+                if (byte1 == SYSEX_END)
+                    event.Event = MIDI_EVENT(cable, SYSEX_ENDS_IN_2);
+                else
+                    event.Event = MIDI_EVENT(cable, SYSEX_START_OR_CONT);
+                break;
+            case 1:
+                if (byte0 == SYSEX_END)
+                    event.Event = MIDI_EVENT(cable, SYSEX_ENDS_IN_1);
+                else
+                    event.Event = MIDI_EVENT(cable, SYSEX_START_OR_CONT);
+                break;
+            default:
+                return; // invalid cnt
+        }
+    } else {
+        // deal with 'system common' messages
+        // TODO are there any more?
+        switch (byte0 & 0xF0) {
+            case MIDI_SONGPOSITION:
+                event.Event = MIDI_EVENT(cable, SYS_COMMON_3);
+                break;
+            case MIDI_SONGSELECT:
+            case MIDI_TC_QUARTERFRAME:
+                event.Event = MIDI_EVENT(cable, SYS_COMMON_2);
+                break;
+            default:
+                event.Event = MIDI_EVENT(cable, byte0);
+                break;
+        }
+    }
+
+    send_midi_packet(&event);
+}
+
+static void usb_get_midi(MidiDevice* device) {
+    MIDI_EventPacket_t event;
+    while (recv_midi_packet(&event)) {
+        midi_packet_length_t length = midi_packet_length(event.Data1);
+        uint8_t              input[3];
+        input[0] = event.Data1;
+        input[1] = event.Data2;
+        input[2] = event.Data3;
+        if (length == UNDEFINED) {
+            // sysex
+            if (event.Event == MIDI_EVENT(0, SYSEX_START_OR_CONT) || event.Event == MIDI_EVENT(0, SYSEX_ENDS_IN_3)) {
+                length = 3;
+            } else if (event.Event == MIDI_EVENT(0, SYSEX_ENDS_IN_2)) {
+                length = 2;
+            } else if (event.Event == MIDI_EVENT(0, SYSEX_ENDS_IN_1)) {
+                length = 1;
+            } else {
+                // XXX what to do?
+            }
+        }
+
+        // pass the data to the device input function
+        if (length != UNDEFINED) midi_device_input(device, length, input);
+    }
+}
+
+static void fallthrough_callback(MidiDevice* device, uint16_t cnt, uint8_t byte0, uint8_t byte1, uint8_t byte2) {
+#ifdef AUDIO_ENABLE
+    if (cnt == 3) {
+        switch (byte0 & 0xF0) {
+            case MIDI_NOTEON:
+                play_note(((double)261.6) * pow(2.0, -4.0) * pow(2.0, (byte1 & 0x7F) / 12.0), (byte2 & 0x7F) / 8);
+                break;
+            case MIDI_NOTEOFF:
+                stop_note(((double)261.6) * pow(2.0, -4.0) * pow(2.0, (byte1 & 0x7F) / 12.0));
+                break;
+        }
+    }
+    if (byte0 == MIDI_STOP) {
+        stop_all_notes();
+    }
+#endif
+}
+
+static void cc_callback(MidiDevice* device, uint8_t chan, uint8_t num, uint8_t val) {
+    // sending it back on the next channel
+    // midi_send_cc(device, (chan + 1) % 16, num, val);
+}
+
+void midi_init(void);
+
+void setup_midi(void) {
+#ifdef MIDI_ADVANCED
+    midi_init();
+#endif
+    midi_device_init(&midi_device);
+    midi_device_set_send_func(&midi_device, usb_send_func);
+    midi_device_set_pre_input_process_func(&midi_device, usb_get_midi);
+    midi_register_fallthrough_callback(&midi_device, fallthrough_callback);
+    midi_register_cc_callback(&midi_device, cc_callback);
+}
-- 
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