From 1264da89c8ff46f575ecb3d61d3c9eef05eaea09 Mon Sep 17 00:00:00 2001
From: Alan Cox <alan@linux.intel.com>
Date: Sat, 14 Feb 2015 16:43:58 +0000
Subject: [PATCH] disciple: sector wrap, notes on +D

---
 Kernel/platform-zx128/devfd.c    | 23 +++++++++++--------
 Kernel/platform-zx128/disciple.s | 39 ++++++++++----------------------
 2 files changed, 26 insertions(+), 36 deletions(-)

diff --git a/Kernel/platform-zx128/devfd.c b/Kernel/platform-zx128/devfd.c
index 45ab1c19..a4407a0d 100644
--- a/Kernel/platform-zx128/devfd.c
+++ b/Kernel/platform-zx128/devfd.c
@@ -10,8 +10,7 @@
 #define OPDIR_WRITE	2
 
 #define FD_READ		0x80
-#define FD_WRITE	0xA0
-#define FD_WRITE_PCOMP	0xA4
+#define FD_WRITE	0xA2
 
 /*
  *	TODO:
@@ -19,8 +18,6 @@
  *	- detect SS v DS
  */
 
-static uint8_t motorct;
-
 /* We are a bit rude with this as we just bash it without sharing */
 __sfr __at 0x1F control;
 
@@ -39,6 +36,7 @@ static int fd_transfer(uint8_t minor, bool is_read, uint8_t rawflag)
     uint8_t *driveptr = fd_tab + minor;
     uint8_t nblock;
     uint8_t cval;
+    uint8_t sec;
 
     if(rawflag == 2)
         goto bad2;
@@ -60,7 +58,7 @@ static int fd_transfer(uint8_t minor, bool is_read, uint8_t rawflag)
 
     fd_cmd[0] = is_read ? FD_READ : FD_WRITE;
     fd_cmd[1] = block / 20;
-    fd_cmd[2] = (block % 20) + 1;
+    sec = (block % 20) + 1;
     fd_cmd[3] = is_read ? OPDIR_READ: OPDIR_WRITE;
     fd_cmd[4] = dptr & 0xFF;
     fd_cmd[5] = dptr >> 8;
@@ -72,10 +70,13 @@ static int fd_transfer(uint8_t minor, bool is_read, uint8_t rawflag)
 
 
     while (ct < nblock) {
-        if (fd_cmd[2] > 10)
+        if (sec > 10) {
             control = cval | 2;
-        else
+            fd_cmd[2] = sec - 10;
+        } else {
             control = cval;
+            fd_cmd[2] = sec;
+        }
         if (!is_read && fd_cmd[1] > 64)
             fd_cmd[0] |= 4;	/* Write precompensation on */
 
@@ -89,9 +90,13 @@ static int fd_transfer(uint8_t minor, bool is_read, uint8_t rawflag)
         /* FIXME: need to do SD v DD detection */
         if (tries == 4)
             goto bad;
-        /* FIXME: this doesn't work for a big raw read that changes track */
         fd_cmd[5]+= 2;	/* Move on 512 bytes in the buffer */
-        fd_cmd[2]++;	/* Next sector */
+        sec++;
+        /* Step a track */
+        if (sec > 20) {
+            sec = 1;
+            fd_cmd[1]++;
+        }
         ct++;
     }
     return 1;
diff --git a/Kernel/platform-zx128/disciple.s b/Kernel/platform-zx128/disciple.s
index 6b10b0e7..2a7dc40a 100644
--- a/Kernel/platform-zx128/disciple.s
+++ b/Kernel/platform-zx128/disciple.s
@@ -35,12 +35,22 @@
 ;	0x58 - step in
 ;	0xA0 - write + 0x02 for spin up etc, + 0x08? for precomp
 ;	0xD0 - reset (then wait about 1mS)
+;
+;
+;	This code ought to work on the Plus-D as well with a few changes
+;
+;	The +D uses ports
+;	0xE3	status/cmd
+;	0xEB	track
+;	0xF3	sector
+;	0xFB	data
+;	0xEF	control
+;	bits 0-1: drive select
+;	bit 7: side select
 ;
 
 	.globl _fd_reset
 	.globl _fd_operation
-	.globl _fd_motor_on
-	.globl _fd_motor_off
 	.globl _fd_selected
 	.globl _fd_tab
 	.globl _fd_cmd
@@ -335,35 +345,10 @@ _fd_operation:
 	ld	h, #0
 	pop	ix
 	ret
-;
-;	C interface fd_motor_on(uint16_t drivesel)
-;
-;	Selects this drive and turns on the motors. Also pass in the
-;	choice of density
-;
-;	bits 0-3:	select that drive
-;	bit 4:		side (must rewrite each drive change)
-;	bit 5:		precompensation (not set here but in the I/O ops)
-;	bit 6:		synchronize I/O by stalling the CPU (don't set this)
-;	bit 7:		set for double density (MFM)
-;
-;
-_fd_motor_on:
-	ret
-
-;
-;	C interface fd_motor_off(void)
-;
-;	Turns off the drive motors, deselects all drives
-;
-_fd_motor_off:
-	ret
 
 	.area _COMMONDATA
 curdrive:
 	.db	0xff
-motor_running:
-	.db	0
 fdcctrl:
 	.db	0
 fdc_active:
-- 
2.34.1