From 9c96e7c7a25807bd3da3b0bfa548fc2b224a8c6f Mon Sep 17 00:00:00 2001
From: Dean Netherton <dinoboards@netherton.org>
Date: Sat, 29 Mar 2025 18:52:34 +1100
Subject: [PATCH] ch376-native: fixed issue with TMSMODE_MSXUKY selected when
 no usb keyboard is present on boot

The TMS driver would always install a USB keyboard pooling interrupt, despite no keyboard present

This would load the CPU and prevent other I/O operations
---
 .../HBIOS/ch376-native/keyboard/kyb-init.c.s  | 99 ++++++++++---------
 .../source-doc/keyboard/kyb-init.c            |  5 +-
 Source/HBIOS/ch376kyb.asm                     |  6 +-
 3 files changed, 59 insertions(+), 51 deletions(-)

diff --git a/Source/HBIOS/ch376-native/keyboard/kyb-init.c.s b/Source/HBIOS/ch376-native/keyboard/kyb-init.c.s
index e7fed9b8..8bcaa66e 100644
--- a/Source/HBIOS/ch376-native/keyboard/kyb-init.c.s
+++ b/Source/HBIOS/ch376-native/keyboard/kyb-init.c.s
@@ -62,7 +62,7 @@ _report:
 ;--------------------------------------------------------
 ; code
 ;--------------------------------------------------------
-;source-doc/keyboard/kyb-init.c:12: void keyboard_init(void) {
+;source-doc/keyboard/kyb-init.c:12: uint8_t keyboard_init(void) __sdcccall(1) {
 ; ---------------------------------
 ; Function keyboard_init
 ; ---------------------------------
@@ -118,7 +118,8 @@ l_keyboard_init_00105:
 	inc	sp
 	ld	hl, (_keyboard_config)
 	call	_hid_set_idle
-;source-doc/keyboard/kyb-init.c:32: return;
+;source-doc/keyboard/kyb-init.c:32: return 1;
+	ld	a,0x01
 	jr	l_keyboard_init_00108
 l_keyboard_init_00106:
 ;source-doc/keyboard/kyb-init.c:34: } while (++index != MAX_NUMBER_OF_DEVICES + 1);
@@ -130,9 +131,11 @@ l_keyboard_init_00106:
 l_keyboard_init_00107:
 ;source-doc/keyboard/kyb-init.c:36: print_string("\r\nUSB: KEYBOARD: NOT FOUND$");
 	ld	hl,kyb_init_str_2
-	jp	_print_string
+	call	_print_string
+;source-doc/keyboard/kyb-init.c:37: return 0;
+	xor	a
 l_keyboard_init_00108:
-;source-doc/keyboard/kyb-init.c:37: }
+;source-doc/keyboard/kyb-init.c:38: }
 	ret
 kyb_init_str_0:
 	DEFB 0x0d
@@ -147,7 +150,7 @@ kyb_init_str_2:
 	DEFB 0x0a
 	DEFM "USB: KEYBOARD: NOT FOUND$"
 	DEFB 0x00
-;source-doc/keyboard/kyb-init.c:50:
+;source-doc/keyboard/kyb-init.c:51:
 ; ---------------------------------
 ; Function keyboard_buf_put
 ; ---------------------------------
@@ -155,42 +158,42 @@ _keyboard_buf_put:
 	push	ix
 	ld	ix,0
 	add	ix,sp
-;source-doc/keyboard/kyb-init.c:51: void keyboard_buf_put(const uint8_t modifier_keys, const uint8_t key_code) {
+;source-doc/keyboard/kyb-init.c:52: void keyboard_buf_put(const uint8_t modifier_keys, const uint8_t key_code) {
 	ld	a,(ix+5)
 	sub	0x80
 	jr	NC,l_keyboard_buf_put_00112
 	ld	a,(ix+5)
 	or	a
-;source-doc/keyboard/kyb-init.c:52: if (key_code >= 0x80 || key_code == 0)
-;source-doc/keyboard/kyb-init.c:55: // if already reported, just skip it
+;source-doc/keyboard/kyb-init.c:53: if (key_code >= 0x80 || key_code == 0)
+;source-doc/keyboard/kyb-init.c:56: // if already reported, just skip it
 	jr	Z,l_keyboard_buf_put_00112
 	ld	c,0x00
 l_keyboard_buf_put_00110:
 	ld	a, c
 	sub	0x06
 	jr	NC,l_keyboard_buf_put_00106
-;source-doc/keyboard/kyb-init.c:56: for (uint8_t i = 0; i < 6; i++)
+;source-doc/keyboard/kyb-init.c:57: for (uint8_t i = 0; i < 6; i++)
 	ld	b,0x00
 	ld	hl,_previous_keyCodes
 	add	hl, bc
 	ld	a, (hl)
 	sub	(ix+5)
-;source-doc/keyboard/kyb-init.c:57: if (previous_keyCodes[i] == key_code)
+;source-doc/keyboard/kyb-init.c:58: if (previous_keyCodes[i] == key_code)
 	jr	Z,l_keyboard_buf_put_00112
-;source-doc/keyboard/kyb-init.c:55: // if already reported, just skip it
+;source-doc/keyboard/kyb-init.c:56: // if already reported, just skip it
 	inc	c
 	jr	l_keyboard_buf_put_00110
 l_keyboard_buf_put_00106:
-;source-doc/keyboard/kyb-init.c:59:
+;source-doc/keyboard/kyb-init.c:60:
 	ld	a, (_write_index)
 	inc	a
 	and	0x07
 	ld	c, a
-;source-doc/keyboard/kyb-init.c:60: uint8_t next_write_index = (write_index + 1) & KEYBOARD_BUFFER_SIZE_MASK;
+;source-doc/keyboard/kyb-init.c:61: uint8_t next_write_index = (write_index + 1) & KEYBOARD_BUFFER_SIZE_MASK;
 	ld	a,(_read_index)
 	sub	c
 	jr	Z,l_keyboard_buf_put_00112
-;source-doc/keyboard/kyb-init.c:61: if (next_write_index != read_index) { // Check if buffer is not full
+;source-doc/keyboard/kyb-init.c:62: if (next_write_index != read_index) { // Check if buffer is not full
 	ld	de,_buffer+0
 	ld	hl, (_write_index)
 	ld	h,0x00
@@ -198,7 +201,7 @@ l_keyboard_buf_put_00106:
 	add	hl, de
 	ld	a,(ix+4)
 	ld	(hl), a
-;source-doc/keyboard/kyb-init.c:62: buffer[write_index].modifier_keys = modifier_keys;
+;source-doc/keyboard/kyb-init.c:63: buffer[write_index].modifier_keys = modifier_keys;
 	ld	hl, (_write_index)
 	ld	h,0x00
 	add	hl, hl
@@ -206,39 +209,39 @@ l_keyboard_buf_put_00106:
 	inc	hl
 	ld	a,(ix+5)
 	ld	(hl), a
-;source-doc/keyboard/kyb-init.c:63: buffer[write_index].key_code      = key_code;
+;source-doc/keyboard/kyb-init.c:64: buffer[write_index].key_code      = key_code;
 	ld	hl,_write_index
 	ld	(hl), c
 l_keyboard_buf_put_00112:
-;source-doc/keyboard/kyb-init.c:65: }
+;source-doc/keyboard/kyb-init.c:66: }
 	pop	ix
 	ret
-;source-doc/keyboard/kyb-init.c:67:
+;source-doc/keyboard/kyb-init.c:68:
 ; ---------------------------------
 ; Function keyboard_buf_size
 ; ---------------------------------
 _keyboard_buf_size:
-;source-doc/keyboard/kyb-init.c:68: uint8_t keyboard_buf_size() __sdcccall(1) {
+;source-doc/keyboard/kyb-init.c:69: uint8_t keyboard_buf_size() __sdcccall(1) {
 	ld	a,(_write_index)
 	ld	hl,_read_index
 	sub	(hl)
 	jr	C,l_keyboard_buf_size_00102
-;source-doc/keyboard/kyb-init.c:69: if (write_index >= read_index)
+;source-doc/keyboard/kyb-init.c:70: if (write_index >= read_index)
 	ld	a,(_write_index)
 	ld	hl,_read_index
 	sub	(hl)
 	jr	l_keyboard_buf_size_00103
 l_keyboard_buf_size_00102:
-;source-doc/keyboard/kyb-init.c:71:
+;source-doc/keyboard/kyb-init.c:72:
 	ld	hl, (_read_index)
 	ld	a,0x08
 	sub	l
 	ld	hl, (_write_index)
 	add	a, l
 l_keyboard_buf_size_00103:
-;source-doc/keyboard/kyb-init.c:72: return KEYBOARD_BUFFER_SIZE - read_index + write_index;
+;source-doc/keyboard/kyb-init.c:73: return KEYBOARD_BUFFER_SIZE - read_index + write_index;
 	ret
-;source-doc/keyboard/kyb-init.c:74:
+;source-doc/keyboard/kyb-init.c:75:
 ; ---------------------------------
 ; Function keyboard_buf_get_next
 ; ---------------------------------
@@ -248,53 +251,53 @@ _keyboard_buf_get_next:
 	add	ix,sp
 	push	af
 	push	af
-;source-doc/keyboard/kyb-init.c:75: uint32_t keyboard_buf_get_next() {
+;source-doc/keyboard/kyb-init.c:76: uint32_t keyboard_buf_get_next() {
 	ld	a,(_write_index)
 	ld	hl,_read_index
 	sub	(hl)
 	jr	NZ,l_keyboard_buf_get_next_00102
-;source-doc/keyboard/kyb-init.c:76: if (write_index == read_index) // Check if buffer is empty
+;source-doc/keyboard/kyb-init.c:77: if (write_index == read_index) // Check if buffer is empty
 	ld	hl,0xff00
 	ld	e, h
 	ld	d, h
 	jr	l_keyboard_buf_get_next_00105
 l_keyboard_buf_get_next_00102:
-;source-doc/keyboard/kyb-init.c:78:
+;source-doc/keyboard/kyb-init.c:79:
 	ld	bc,_buffer+0
 	ld	hl, (_read_index)
 	ld	h,0x00
 	add	hl, hl
 	add	hl, bc
 	ld	b, (hl)
-;source-doc/keyboard/kyb-init.c:79: const uint8_t modifier_key = buffer[read_index].modifier_keys;
+;source-doc/keyboard/kyb-init.c:80: const uint8_t modifier_key = buffer[read_index].modifier_keys;
 	inc	hl
 	ld	c, (hl)
-;source-doc/keyboard/kyb-init.c:80: const uint8_t key_code     = buffer[read_index].key_code;
+;source-doc/keyboard/kyb-init.c:81: const uint8_t key_code     = buffer[read_index].key_code;
 	ld	a, (_read_index)
 	inc	a
 	and	0x07
 	ld	(_read_index),a
-;source-doc/keyboard/kyb-init.c:82:
+;source-doc/keyboard/kyb-init.c:83:
 	ld	a, c
 	sub	0x39
 	jr	NZ,l_keyboard_buf_get_next_00104
-;source-doc/keyboard/kyb-init.c:83: if (key_code == KEY_CODE_CAPS_LOCK) {
+;source-doc/keyboard/kyb-init.c:84: if (key_code == KEY_CODE_CAPS_LOCK) {
 	ld	hl,_caps_lock_engaged
 	ld	a, (hl)
 	xor	0x01
 	ld	(hl), a
-;source-doc/keyboard/kyb-init.c:84: caps_lock_engaged = !caps_lock_engaged;
+;source-doc/keyboard/kyb-init.c:85: caps_lock_engaged = !caps_lock_engaged;
 	call	_keyboard_buf_get_next
 	jr	l_keyboard_buf_get_next_00105
 l_keyboard_buf_get_next_00104:
-;source-doc/keyboard/kyb-init.c:87:
+;source-doc/keyboard/kyb-init.c:88:
 	push	bc
 	ld	l, c
 	ld	a, b
 	call	_scancode_to_char
 	ld	e, a
 	pop	bc
-;source-doc/keyboard/kyb-init.c:89: /* D = modifier, e-> char, H = 0, L=>code */
+;source-doc/keyboard/kyb-init.c:90: /* D = modifier, e-> char, H = 0, L=>code */
 	xor	a
 	ld	(ix-1),b
 	xor	a
@@ -311,32 +314,32 @@ l_keyboard_buf_get_next_00104:
 	pop	hl
 	push	hl
 l_keyboard_buf_get_next_00105:
-;source-doc/keyboard/kyb-init.c:90: return (uint32_t)modifier_key << 24 | (uint32_t)c << 16 | key_code;
+;source-doc/keyboard/kyb-init.c:91: return (uint32_t)modifier_key << 24 | (uint32_t)c << 16 | key_code;
 	ld	sp, ix
 	pop	ix
 	ret
-;source-doc/keyboard/kyb-init.c:92:
+;source-doc/keyboard/kyb-init.c:93:
 ; ---------------------------------
 ; Function keyboard_buf_flush
 ; ---------------------------------
 _keyboard_buf_flush:
-;source-doc/keyboard/kyb-init.c:93: void keyboard_buf_flush() {
-;source-doc/keyboard/kyb-init.c:94: write_index = 0;
+;source-doc/keyboard/kyb-init.c:94: void keyboard_buf_flush() {
+;source-doc/keyboard/kyb-init.c:95: write_index = 0;
 	xor	a
 	ld	(_write_index),a
 	ld	(_read_index),a
-;source-doc/keyboard/kyb-init.c:95: read_index  = 0;
+;source-doc/keyboard/kyb-init.c:96: read_index  = 0;
 	ret
-;source-doc/keyboard/kyb-init.c:101:
+;source-doc/keyboard/kyb-init.c:102:
 ; ---------------------------------
 ; Function keyboard_tick
 ; ---------------------------------
 _keyboard_tick:
-;source-doc/keyboard/kyb-init.c:102: void keyboard_tick(void) {
+;source-doc/keyboard/kyb-init.c:103: void keyboard_tick(void) {
 	ld	hl,_in_critical_usb_section
 	ld	a, (hl)
 	or	a
-;source-doc/keyboard/kyb-init.c:103: if (is_in_critical_section())
+;source-doc/keyboard/kyb-init.c:104: if (is_in_critical_section())
 	jr	NZ,l_keyboard_tick_00111
 ;././source-doc/base-drv//ch376.h:110: #endif
 	ld	l,0x0b
@@ -349,7 +352,7 @@ _keyboard_tick:
 	ld	a,0x1f
 	ld	bc,_CH376_DATA_PORT
 	out	(c), a
-;source-doc/keyboard/kyb-init.c:106: ch_configure_nak_retry_disable();
+;source-doc/keyboard/kyb-init.c:107: ch_configure_nak_retry_disable();
 	ld	bc,_report
 	ld	hl, (_keyboard_config)
 	ld	a,0x08
@@ -374,10 +377,10 @@ _keyboard_tick:
 	ld	a,0xdf
 	ld	bc,_CH376_DATA_PORT
 	out	(c), a
-;source-doc/keyboard/kyb-init.c:108: ch_configure_nak_retry_3s();
+;source-doc/keyboard/kyb-init.c:109: ch_configure_nak_retry_3s();
 	ld	hl,_result
 	ld	a, (hl)
-;source-doc/keyboard/kyb-init.c:109: if (result == 0)
+;source-doc/keyboard/kyb-init.c:110: if (result == 0)
 	or	a
 	jr	NZ,l_keyboard_tick_00111
 	ld	c,a
@@ -385,7 +388,7 @@ l_keyboard_tick_00109:
 	ld	a, c
 	sub	0x06
 	ret	NC
-;source-doc/keyboard/kyb-init.c:110: for (uint8_t i = 0; i < 6; i++) {
+;source-doc/keyboard/kyb-init.c:111: for (uint8_t i = 0; i < 6; i++) {
 	ld	a,+((_report+2) & 0xFF)
 	add	a, c
 	ld	e, a
@@ -404,17 +407,17 @@ l_keyboard_tick_00109:
 	pop	af
 	pop	de
 	pop	bc
-;source-doc/keyboard/kyb-init.c:111: keyboard_buf_put(report.bModifierKeys, report.keyCode[i]);
+;source-doc/keyboard/kyb-init.c:112: keyboard_buf_put(report.bModifierKeys, report.keyCode[i]);
 	ld	b,0x00
 	ld	hl,_previous_keyCodes
 	add	hl, bc
 	ld	a, (de)
 	ld	(hl), a
-;source-doc/keyboard/kyb-init.c:109: if (result == 0)
+;source-doc/keyboard/kyb-init.c:110: if (result == 0)
 	inc	c
 	jr	l_keyboard_tick_00109
 l_keyboard_tick_00111:
-;source-doc/keyboard/kyb-init.c:113: }
+;source-doc/keyboard/kyb-init.c:114: }
 	ret
 _keyboard_config:
 	DEFW +0x0000
diff --git a/Source/HBIOS/ch376-native/source-doc/keyboard/kyb-init.c b/Source/HBIOS/ch376-native/source-doc/keyboard/kyb-init.c
index e0b1e59a..aba62ac5 100644
--- a/Source/HBIOS/ch376-native/source-doc/keyboard/kyb-init.c
+++ b/Source/HBIOS/ch376-native/source-doc/keyboard/kyb-init.c
@@ -9,7 +9,7 @@
 static device_config_keyboard *keyboard_config = 0;
 extern bool                    caps_lock_engaged;
 
-void keyboard_init(void) {
+uint8_t keyboard_init(void) __sdcccall(1) {
 
   uint8_t index   = 1;
   keyboard_config = NULL;
@@ -29,11 +29,12 @@ void keyboard_init(void) {
 
       hid_set_protocol(keyboard_config, 1);
       hid_set_idle(keyboard_config, 0x80);
-      return;
+      return 1;
     }
   } while (++index != MAX_NUMBER_OF_DEVICES + 1);
 
   print_string("\r\nUSB: KEYBOARD: NOT FOUND$");
+  return 0;
 }
 
 #define KEYBOARD_BUFFER_SIZE      8
diff --git a/Source/HBIOS/ch376kyb.asm b/Source/HBIOS/ch376kyb.asm
index b6f3af6c..ac971673 100644
--- a/Source/HBIOS/ch376kyb.asm
+++ b/Source/HBIOS/ch376kyb.asm
@@ -38,6 +38,10 @@ SCAN_INT_PERIOD:	.EQU	2
 UKY_INTSTK:	; 128 bytes for keyboard interrupt stack - need ~52 bytes???
 
 CHUKB_INIT:
+	CALL	_keyboard_init
+	OR	A
+	RET	Z
+
 	; INSTALL INTERRUPT HANDLER
 	LD	HL, (VEC_TICK+1)
 	LD	(VEC_CHUKB_TICK+1), HL
@@ -45,7 +49,7 @@ CHUKB_INIT:
 	LD	HL, CHUKB_TICK
 	LD	(VEC_TICK+1), HL
 
-	JP	_keyboard_init
+	RET
 
 CHUKB_TICK:
 	LD      A, SCAN_INT_PERIOD			; SCAN THE KEYBOARD EVERY 'SCAN_INT_PERIOD' INTERRUPTS.