From e43a939f54c87927e78b95f73648324234db0234 Mon Sep 17 00:00:00 2001
From: Wayne Warthen <wwarthen@gmail.com>
Date: Fri, 21 Apr 2023 17:08:18 -0700
Subject: [PATCH] Improve IDE Device Detection

Per issue #343, some systems could initially detect a non-existent IDE device which would cause a long time-out.  This should resolve the issue.
---
 Source/HBIOS/ide.asm   | 88 ++++++++++++++------------------------
 Source/HBIOS/ppide.asm | 97 ++++++++++++++----------------------------
 Source/ver.inc         |  2 +-
 Source/ver.lib         |  2 +-
 4 files changed, 68 insertions(+), 121 deletions(-)

diff --git a/Source/HBIOS/ide.asm b/Source/HBIOS/ide.asm
index ea823fc4..afd3869e 100644
--- a/Source/HBIOS/ide.asm
+++ b/Source/HBIOS/ide.asm
@@ -1111,6 +1111,7 @@ IDE_PROBE:
 	PRTS(" PROBE$")			; LABEL FOR IO ADDRESS
 #ENDIF
 ;
+	; SELECT DEVICE (MASTER/SLAVE)
 	LD	A,(IDE_DRVHD)
 	;OUT	(IDE_IO_DRVHD),A
 	CALL	IDE_OUT
@@ -1119,21 +1120,44 @@ IDE_PROBE:
 	CALL	PC_SPACE
 	CALL	PRTHEXBYTE
 #ENDIF
-
+;
 	CALL	DELAY			; DELAY ~16US
 ;
-	;LD	C,IDE_IO_STAT
-	;IN	A,(C)
+; TEST FOR PRESENCE OF IDE REGISTERS.  USE LBA0/1 TO SEE
+; IF VALUE CAN BE PERSISTED.  THE USE OF BOTH LBA0 AND LBA1
+; IS TO MAINTAIN CONSISTENCY WITH TGHE THE PPIDE DRIVER BECAUSE
+; PPI ITSELF WILL PERSIST THE LAST VALUE WRITTEN, SO WE USE
+; MULTIPLE REGISTERS TO WORK AROUND THIS FALSE POSITIVE.
+;
+	; $AA -> LBA0
+	LD	A,$AA
+	CALL	IDE_OUT
+	.DB	IDE_REG_LBA0
+;	
+	; $55 => LBA1
+	LD	A,$55
+	CALL	IDE_OUT
+	.DB	IDE_REG_LBA1
+;
+	; TEST LBA0 == $AA
 	CALL	IDE_IN
-	.DB	IDE_REG_STAT
+	.DB	IDE_REG_LBA0
 #IF (IDETRACE >= 3)
 	CALL	PC_SPACE
 	CALL	PRTHEXBYTE
 #ENDIF
-	CP	$FF
-	JP	Z,IDE_NOMEDIA
-	CP	$78
-	JP	Z,IDE_NOMEDIA
+	CP	$AA
+	JP	NZ,IDE_NOMEDIA
+;
+	; TEST LBA1 == $55
+	CALL	IDE_IN
+	.DB	IDE_REG_LBA1
+#IF (IDETRACE >= 3)
+	CALL	PC_SPACE
+	CALL	PRTHEXBYTE
+#ENDIF
+	CP	$55
+	JP	NZ,IDE_NOMEDIA
 ;
 #IF (IDETRACE >= 3)
 	CALL	IDE_REGDUMP
@@ -1159,55 +1183,9 @@ IDE_PROBE0:
 #ENDIF
 	OR	A			; SET FLAGS TO TEST FOR ZERO
 	JP	Z,IDE_NOMEDIA
-;
-	; CHECK SIGNATURE
-#IF (IDETRACE >= 3)
-	CALL	PC_SPACE
-#ENDIF
-	;IN	A,(IDE_IO_COUNT)
-	CALL	IDE_IN
-	.DB	IDE_REG_COUNT
-#IF (IDETRACE >= 3)
-	CALL	PRTHEXBYTE
-#ENDIF
-	CP	$01
-	JP	NZ,IDE_NOMEDIA
-#IF (IDETRACE >= 3)
-	CALL	PC_SPACE
-#ENDIF
-	;IN	A,(IDE_IO_SECT)
-	CALL	IDE_IN
-	.DB	IDE_REG_SECT
-#IF (IDETRACE >= 3)
-	CALL	PRTHEXBYTE
-#ENDIF
-	CP	$01
-	JP	NZ,IDE_NOMEDIA
-#IF (IDETRACE >= 3)
-	CALL	PC_SPACE
-#ENDIF
-	;IN	A,(IDE_IO_CYLLO)
-	CALL	IDE_IN
-	.DB	IDE_REG_CYLLO
-#IF (IDETRACE >= 3)
-	CALL	PRTHEXBYTE
-#ENDIF
-	CP	$00
-	JP	NZ,IDE_NOMEDIA
-#IF (IDETRACE >= 3)
-	CALL	PC_SPACE
-#ENDIF
-	;IN	A,(IDE_IO_CYLHI)
-	CALL	IDE_IN
-	.DB	IDE_REG_CYLHI
-#IF (IDETRACE >= 3)
-	CALL	PRTHEXBYTE
-#ENDIF
-	CP	$00
-	JP	NZ,IDE_NOMEDIA
 ;
 IDE_PROBE1:
-	; SIGNATURE MATCHES ATA DEVICE, RECORD TYPE AND RETURN SUCCESS
+	; ASSUME ATA DEVICE FOR NOW, RECORD TYPE AND RETURN SUCCESS
 	LD	A,IDE_TYPEATA		; TYPE = ATA
 	LD	(IY+IDE_TYPE),A		; SET IT IN INSTANCE DATA
 	XOR	A			; SIGNAL SUCCESS
diff --git a/Source/HBIOS/ppide.asm b/Source/HBIOS/ppide.asm
index 9fc40047..271b1d72 100644
--- a/Source/HBIOS/ppide.asm
+++ b/Source/HBIOS/ppide.asm
@@ -1127,6 +1127,7 @@ PPIDE_PROBE:
 	PRTS(" PROBE$")			; LABEL FOR IO ADDRESS
 #ENDIF
 ;
+	; SELECT DEVICE (MASTER/SLAVE)
 	LD	A,(PPIDE_DRVHD)
 	;OUT	(IDE_IO_DRVHD),A
 	CALL	PPIDE_OUT
@@ -1135,30 +1136,44 @@ PPIDE_PROBE:
 	CALL	PC_SPACE
 	CALL	PRTHEXBYTE
 #ENDIF
-
+;
 	CALL	DELAY			; DELAY ~16US
 ;
-	; BELOW TESTS FOR EXISTENCE OF AN IDE CONTROLLER ON THE
-	; PPIDE INTERFACE.  WE WRITE A VALUE OF ZERO FIRST SO THAT
-	; THE PPI BUS HOLD WILL RETURN A VALUE OF ZERO IF THERE IS
-	; NOTHING CONNECTED TO PPI PORT A.  THEN WE READ THE STATUS
-	; REGISTER.  IF AN IDE CONTROLLER IS THERE, IT SHOULD ALWAYS
-	; RETURN SOMETHING OTHER THAN ZERO.  IF AN IDE CONTROLLER IS
-	; THERE, THEN THE VALUE WRITTEN TO PPI PORT A IS IGNORED
-	; BECAUSE THE WRITE SIGNAL IS NEVER PULSED.
-	XOR	A
-	;OUT	(PPIDE_IO_DATALO),A
-	LD	C,(IY+PPIDE_DATALO)	; PPI PORT A, DATALO
-	OUT	(C),A
-;	IN	A,(PPIDE_REG_STAT)	; GET STATUS
+; TEST FOR PRESENCE OF IDE REGISTERS.  USE LBA0/1 TO SEE
+; IF VALUE CAN BE PERSISTED.  THE USE OF BOTH LBA0 AND LBA1
+; IS TO MAINTAIN CONSISTENCY WITH TGHE THE PPIDE DRIVER BECAUSE
+; PPI ITSELF WILL PERSIST THE LAST VALUE WRITTEN, SO WE USE
+; MULTIPLE REGISTERS TO WORK AROUND THIS FALSE POSITIVE.
+;
+	; $AA -> LBA0
+	LD	A,$AA
+	CALL	PPIDE_OUT
+	.DB	PPIDE_REG_LBA0
+;	
+	; $55 => LBA1
+	LD	A,$55
+	CALL	PPIDE_OUT
+	.DB	PPIDE_REG_LBA1
+;
+	; TEST LBA0 == $AA
 	CALL	PPIDE_IN
-	.DB	PPIDE_REG_STAT
+	.DB	PPIDE_REG_LBA0
 #IF (PPIDETRACE >= 3)
 	CALL	PC_SPACE
 	CALL	PRTHEXBYTE
 #ENDIF
-	OR	A
-	JP	Z,PPIDE_NOMEDIA
+	CP	$AA
+	JP	NZ,PPIDE_NOMEDIA
+;
+	; TEST LBA1 == $55
+	CALL	PPIDE_IN
+	.DB	PPIDE_REG_LBA1
+#IF (PPIDETRACE >= 3)
+	CALL	PC_SPACE
+	CALL	PRTHEXBYTE
+#ENDIF
+	CP	$55
+	JP	NZ,PPIDE_NOMEDIA
 ;
 #IF (PPIDETRACE >= 3)
 	CALL	PPIDE_REGDUMP
@@ -1184,55 +1199,9 @@ PPIDE_PROBE0:
 #ENDIF
 	OR	A			; SET FLAGS TO TEST FOR ZERO
 	JP	Z,PPIDE_NOMEDIA		; CONTINUE IF NON-ZERO
-;
-	; CHECK SIGNATURE
-#IF (PPIDETRACE >= 3)
-	CALL	PC_SPACE
-#ENDIF
-	;IN	A,(PPIDE_REG_COUNT)
-	CALL	PPIDE_IN
-	.DB	PPIDE_REG_COUNT
-#IF (PPIDETRACE >= 3)
-	CALL	PRTHEXBYTE
-#ENDIF
-	CP	$01
-	JP	NZ,PPIDE_NOMEDIA
-#IF (PPIDETRACE >= 3)
-	CALL	PC_SPACE
-#ENDIF
-	;IN	A,(PPIDE_REG_SECT)
-	CALL	PPIDE_IN
-	.DB	PPIDE_REG_SECT
-#IF (PPIDETRACE >= 3)
-	CALL	PRTHEXBYTE
-#ENDIF
-	CP	$01
-	JP	NZ,PPIDE_NOMEDIA
-#IF (PPIDETRACE >= 3)
-	CALL	PC_SPACE
-#ENDIF
-	;IN	A,(PPIDE_REG_CYLLO)
-	CALL	PPIDE_IN
-	.DB	PPIDE_REG_CYLLO
-#IF (PPIDETRACE >= 3)
-	CALL	PRTHEXBYTE
-#ENDIF
-	CP	$00
-	JP	NZ,PPIDE_NOMEDIA
-#IF (PPIDETRACE >= 3)
-	CALL	PC_SPACE
-#ENDIF
-	;IN	A,(PPIDE_REG_CYLHI)
-	CALL	PPIDE_IN
-	.DB	PPIDE_REG_CYLHI
-#IF (PPIDETRACE >= 3)
-	CALL	PRTHEXBYTE
-#ENDIF
-	CP	$00
-	JP	NZ,PPIDE_NOMEDIA
 ;
 PPIDE_PROBE1:
-	; SIGNATURE MATCHES ATA DEVICE, RECORD TYPE AND RETURN SUCCESS
+	; ASSUME ATA DEVICE FOR NOW, RECORD TYPE AND RETURN SUCCESS
 	LD	A,PPIDE_TYPEATA		; TYPE = ATA
 	LD	(IY+PPIDE_TYPE),A	; SET IT IN INSTANCE DATA
 	XOR	A			; SIGNAL SUCCESS
diff --git a/Source/ver.inc b/Source/ver.inc
index 390fc590..d5e9990c 100644
--- a/Source/ver.inc
+++ b/Source/ver.inc
@@ -2,7 +2,7 @@
 #DEFINE	RMN	3
 #DEFINE	RUP	0
 #DEFINE	RTP	0
-#DEFINE BIOSVER	"3.3.0-dev.4"
+#DEFINE BIOSVER	"3.3.0-dev.5"
 #define rmj	RMJ
 #define rmn	RMN
 #define rup	RUP
diff --git a/Source/ver.lib b/Source/ver.lib
index f5a6b1f8..845f0f6b 100644
--- a/Source/ver.lib
+++ b/Source/ver.lib
@@ -3,5 +3,5 @@ rmn	equ	3
 rup	equ	0
 rtp	equ	0
 biosver	macro
-	db	"3.3.0-dev.4"
+	db	"3.3.0-dev.5"
 	endm