trs80, fd: update the floppy disk driver

This is sufficient to mount the root file system and go hunting for init. It
will probably go further still once the other bits are in place

diff --git a/Kernel/platform-trs80/devfd.c b/Kernel/platform-trs80/devfd.c
index 170718f..019a03f 100644 (file)
--- a/Kernel/platform-trs80/devfd.c
+++ b/Kernel/platform-trs80/devfd.c
@@ -9,12 +9,12 @@
 #define OPDIR_READ     1
 #define OPDIR_WRITE    2
 
-#define FD_READ                0x88    /* 2797 needs 0x88, 1797 needs 0x80 */
-#define FD_WRITE       0xA8    /* Likewise A8 v A0 */
+#define FD_READ                0x80    /* 2797 needs 0x88, 1797 needs 0x80 */
+#define FD_WRITE       0xA0    /* Likewise A8 v A0 */
 
 static uint8_t motorct;
 static uint8_t fd_selected = 0xFF;
-static uint8_t fd_tab[MAX_FD];
+static uint8_t fd_tab[MAX_FD] = { 0xFF, 0xFF, 0xFF, 0xFF };
 
 /*
  *     We only support normal block I/O for the moment. We do need to
@@ -37,15 +37,19 @@ static int fd_transfer(uint8_t minor, bool is_read, uint8_t rawflag)
         goto bad2;
 
     if (fd_selected != minor) {
-        uint8_t err = fd_motor_on(selmap[minor]);
+        uint8_t err;
+        /* FIXME: We force DD for now */
+        err = fd_motor_on(selmap[minor]|0x80);
         if (err)
             goto bad;
     }
 
+    if (*driveptr == 0xFF)
+        fd_reset(driveptr);
+
     dptr = (uint16_t)udata.u_buf->bf_data;
     block = udata.u_buf->bf_blk;
 
-//    kprintf("Issue command: drive %d\n", minor);
     cmd[0] = is_read ? FD_READ : FD_WRITE;
     cmd[1] = block / 9;                /* 2 sectors per block */
     cmd[2] = ((block % 9) << 1) + 1;   /*eww.. */
@@ -62,7 +66,7 @@ static int fd_transfer(uint8_t minor, bool is_read, uint8_t rawflag)
                 fd_reset(driveptr);
         }
         /* FIXME: should we try the other half and then bale out ? */
-        if (tries == 3)
+        if (tries == 4)
             goto bad;
         cmd[5]++;      /* Move on 256 bytes in the buffer */
         cmd[2]++;      /* Next sector for 2nd block */

diff --git a/Kernel/platform-trs80/floppy.s b/Kernel/platform-trs80/floppy.s
index 400f34e..b26dac5 100644 (file)
--- a/Kernel/platform-trs80/floppy.s
+++ b/Kernel/platform-trs80/floppy.s
@@ -58,14 +58,28 @@ nap:        dec     bc
 ;      The motor off logic is driven from hardware
 ;
 fd_nmi_handler:
+       push    af
+       push    bc
+       ld      a, (fdc_active)
+       or      a
+       jr      z, boring_nmi
        xor     a
        out     (FDCINT), a
        ld      bc, #100
        call    nap
+       pop     bc
+       pop     af
        pop     af              ; discard return address
        jp      fdio_nmiout     ; and jump
 
 ;
+;      FIXME: check for motor off here
+;
+boring_nmi:
+       pop     bc
+       pop     af
+       retn
+;
 ;      Wait for the drive controller to become ready
 ;      Preserve HL, DE
 ;
@@ -85,7 +99,7 @@ waitdisk_l:
        jr      nz, waitdisk_l
        ld      a, #0xD0        ; reset
        out     (FDCREG), a
-       ex      (sp), hl
+       ex      (sp),hl
        ex      (sp),hl
        ex      (sp),hl
        ex      (sp),hl
@@ -103,22 +117,22 @@ fdsetup:
        ld      a, (de)
        out     (FDCTRK), a
        cp      TRACK(ix)
-       jr      z, fdiosetup
+;      jr      z, fdiosetup
 
        ;
        ;       So we can verify
        ;
-       ld      a, SECTOR(ix)
+       ld      a, TRACK(ix)
        out     (FDCDATA), a
+       ld      a, SECTOR(ix)
+       out     (FDCSEC), a
        ;
        ;       Need to seek the disk
        ;
-       ld      a, #0x14        ; seek
+       ld      a, #0x18        ; seek
        out     (FDCREG), a
-       ex      (sp),hl
-       ex      (sp),hl
-       ex      (sp),hl
-       ex      (sp),hl
+       ld      b, #100
+seekwt:        djnz    seekwt
        call    waitdisk
        jr      nz, setuptimeout
        and     #0x18           ; error bits
@@ -152,16 +166,16 @@ fdiosetup:
        ld      de, #0          ; timeout handling
        
        out     (FDCREG), a     ; issue the command
-       ex      (sp),hl ; give the FDC a moment to think
-       ex      (sp),hl
-       ex      (sp),hl
-       ex      (sp),hl
+       ld      b, #0
+rwiowt:        djnz    rwiowt
        ld      a, DIRECT(ix)
        dec     a
        ld      a, (fdcctrl)
        ld      d, a                    ; we need this in a register
                                        ; to meet timing
-       set     6,d                     ; halt mode bit
+       ld      a, #1
+       ld      (fdc_active), a         ; NMI pop and jump
+;      set     6,d                     ; halt mode bit
        jr      z, fdio_in
        jr      nc, fdio_out
 ;
@@ -170,6 +184,8 @@ fdiosetup:
 fdxferdone:
        ei
 fdxferdone2:
+       xor     a
+       ld      (fdc_active), a
        in      a, (FDCREG)
        and     #0x19           ; Error bits + busy
        bit     0, a            ; Wait for busy to drop, return in a
@@ -178,7 +194,7 @@ fdxferdone2:
        out     (FDCCTRL), a
        jr      fdxferdone2
 ;
-;      Write to the disk - HL points to the target buffer
+;      Read from the disk - HL points to the target buffer
 ;
 fdio_in:
        ld      e, #0x16                ; bits to check
@@ -263,20 +279,20 @@ _fd_reset:
        out     (FDCSEC), a
        xor     a
        out     (FDCTRK), a
+       ld      a, #0x0C
        out     (FDCREG), a     ; restore
-       dec     a
+       ld      a, #0xFF
        ld      (hl), a         ; Zap track pointer
-       ex      (sp),hl         ; give the FDC a moment to think
-       ex      (sp),hl
-       ex      (sp),hl
-       ex      (sp),hl
+       ld      b, #0
+_fdr_wait:
+       djnz    _fdr_wait
        
        call    waitdisk
        cp      #0xff
        ret     z
-       and     #0x10           ; Error bit from the reset
+       and     #0x99           ; Error bit from the reset
        ret     nz
-       ld      (hl), a         ; Track 0 correctly hit
+       ld      (hl), a         ; Track 0 correctly hit (so 0)
        ret
 ;
 ;      fd_operation(uint16_t *cmd, uint16_t *drive)
@@ -332,13 +348,10 @@ _fd_motor_on:
 ;      Select our drive
 ;
 notsel:
-       ld      h, a            ; save state as it was
-       or      l
+       ld      a, l
        out     (FDCCTRL), a
        out     (FDCCTRL), a    ; TRS80 erratum apparently needs this
        ld      (fdcctrl), a
-       bit     4, h            ; FIXME - motor bit
-       jr      nz, motor_was_on
        ld      bc, #0x7F00     ; Long delay (may need FE or FF for some disks)
        call    nap
        ; FIXME: longer motor spin up delay goes here (0.5 or 1 second)
@@ -368,11 +381,11 @@ _fd_motor_off:
        ld      (motor_running), a
        ret
 
-       .area _COMMONDATA
 curdrive:
        .db     0xff
 motor_running:
        .db     0
 fdcctrl:
        .db     0
-  
\ No newline at end of file
+fdc_active:
+       .db     0