From 1f1b7dfac87235698d333e7078e8bd28397b0315 Mon Sep 17 00:00:00 2001
From: Leo C <erbl259-lmu@yahoo.de>
Date: Tue, 7 Jun 2016 09:47:46 +0200
Subject: [PATCH] cf_init: do not depend on reset state of the ide command
 block registers.

---
 cbios/cfio.180 | 57 ++++++++++++++++++++++++++++----------------------
 1 file changed, 32 insertions(+), 25 deletions(-)

diff --git a/cbios/cfio.180 b/cbios/cfio.180
index d7d6697..a237bd6 100644
--- a/cbios/cfio.180
+++ b/cbios/cfio.180
@@ -324,30 +324,33 @@ ptab_read:
 	ret
 
 cf_init:
-	ld	hl,25600	;32000/1.25 ms
-	call	wait_nbsy_to
+	ld	hl,25600	; 32000/1.25 ms
+	call	wait_nbsy_to	; wait for BSY == 0
 	jr	c,cfi_error	; return error on timeout
-	in	a,(IDESCnt)
-	dec	a
-	jr	nz,cfi_error
-	in	a,(IDESNum)
-	dec	a
-	jr	nz,cfi_error
-	in	a,(IDECLo)
-	or	a
-	jr	nz,cfi_error
-	in	a,(IDECHi)
-	or	a
-	jr	nz,cfi_error
-	in	a,(IDESDH)
-	or	a
-	jr	nz,cfi_error
-	ld	hl,25600	;32000/1.25 ms
-	call	wait_rdy_to
+
+	ld	hl,25600	; 32000/1.25 ms
+	call	wait_rdy_to	; wait for RDY == 1
 	jr	c,cfi_error	; return error on timeout
 
 	ld	a,0E0h		; assume unit 0, lba mode
 	out	(IdeSDH),a	;
+
+	xor	a		; execute NOP command
+	out	(IdeCmd),a	;
+	ld	hl,100
+	call	wait_rdy_to
+	jr	c,cfi_error
+	and	11111001b	;
+	cp	01010001b	; should return error
+	jr	nz,cfi_error	;
+	ld	a,10h		; execute RECALIBRATE command
+	out	(IdeCmd),a	;
+	ld	hl,100
+	call	wait_rdy_to
+	and	11111001b	;
+	cp	01010000b	; should return ok
+	jr	nz,cfi_error	;
+
 	ld	a,1		; Enable 8-bit data transfer.
 	out	(IDEFeat),a
 	ld	a,CmdSF		; Set feature command
@@ -408,7 +411,9 @@ chk_1:
 
 ; Wait while device is busy with time out
 ;     hl: timer tics (1.25ms) to wait
-;     return carry flag set, if time out
+;     return:
+;	 a: IDE status register
+;	 carry flag set, if time out
 
 wait_nbsy_to:
 	ld	a,1
@@ -421,11 +426,14 @@ wnb_l:
 	call	chk_to
 	jr	nc,wnb_l
 wnb_e:
+	in	a,(IdeCmd)
 	ret
 
 ; Wait for ready signal with time out
 ;     hl: timer tics (1.25ms) to wait
-;     return carry flag set, if time out
+;     return:
+;	 a: IDE status register
+;	 carry flag set, if time out
 
 wait_rdy_to:
 	ld	a,1
@@ -439,6 +447,7 @@ wrdy_l:
 	call	chk_to
 	jr	nc,wrdy_l
 wrdy_e:
+	in	a,(IdeCmd)
 	ret
 
 ;-------------------------------------------------------------------------------
@@ -691,9 +700,8 @@ retry:
 	ld	e,(iy+PTAB_SIZE+0)
 	ld	d,(iy+PTAB_SIZE+1)
 	sbc	hl,de
-	ld	l,a
+	ld	e,a
 	sbc	a,(iy+PTAB_SIZE+2)
-	ld	a,l
 	pop	hl
 	jr	c,lba_ok
 	ld	a,1		; block# >= partition size, return error
@@ -701,8 +709,7 @@ retry:
 
 lba_ok:
 	WAITREADY
-	ld	e,a		; add partition start
-	ld	a,(iy+PTAB_START+0)
+	ld	a,(iy+PTAB_START+0)	; add partition start
 	add	a,l
 	out	(IdeSNum),a
 	ld	a,(iy+PTAB_START+1)
-- 
2.39.2