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| /* SPDX-License-Identifier: GPL-2.0-or-later */
| /*
| * low-level functions for the SWIM floppy controller
| *
| * needs assembly language because is very timing dependent
| * this controller exists only on macintosh 680x0 based
| *
| * Copyright (C) 2004,2008 Laurent Vivier <Laurent@lvivier.info>
| *
| * based on Alastair Bridgewater SWIM analysis, 2001
| * based on netBSD IWM driver (c) 1997, 1998 Hauke Fath.
| *
| * 2004-08-21 (lv) - Initial implementation
| * 2008-11-05 (lv) - add get_swim_mode
| */
|
| .equ write_data, 0x0000
| .equ write_mark, 0x0200
| .equ write_CRC, 0x0400
| .equ write_parameter,0x0600
| .equ write_phase, 0x0800
| .equ write_setup, 0x0a00
| .equ write_mode0, 0x0c00
| .equ write_mode1, 0x0e00
| .equ read_data, 0x1000
| .equ read_mark, 0x1200
| .equ read_error, 0x1400
| .equ read_parameter, 0x1600
| .equ read_phase, 0x1800
| .equ read_setup, 0x1a00
| .equ read_status, 0x1c00
| .equ read_handshake, 0x1e00
|
| .equ o_side, 0
| .equ o_track, 1
| .equ o_sector, 2
| .equ o_size, 3
| .equ o_crc0, 4
| .equ o_crc1, 5
|
| .equ seek_time, 30000
| .equ max_retry, 40
| .equ sector_size, 512
|
| .global swim_read_sector_header
| swim_read_sector_header:
| link %a6, #0
| moveml %d1-%d5/%a0-%a4,%sp@-
| movel %a6@(0x0c), %a4
| bsr mfm_read_addrmark
| moveml %sp@+, %d1-%d5/%a0-%a4
| unlk %a6
| rts
|
| sector_address_mark:
| .byte 0xa1, 0xa1, 0xa1, 0xfe
| sector_data_mark:
| .byte 0xa1, 0xa1, 0xa1, 0xfb
|
| mfm_read_addrmark:
| movel %a6@(0x08), %a3
| lea %a3@(read_handshake), %a2
| lea %a3@(read_mark), %a3
| moveq #-1, %d0
| movew #seek_time, %d2
|
| wait_header_init:
| tstb %a3@(read_error - read_mark)
| moveb #0x18, %a3@(write_mode0 - read_mark)
| moveb #0x01, %a3@(write_mode1 - read_mark)
| moveb #0x01, %a3@(write_mode0 - read_mark)
| tstb %a3@(read_error - read_mark)
| moveb #0x08, %a3@(write_mode1 - read_mark)
|
| lea sector_address_mark, %a0
| moveq #3, %d1
|
| wait_addr_mark_byte:
|
| tstb %a2@
| dbmi %d2, wait_addr_mark_byte
| bpl header_exit
|
| moveb %a3@, %d3
| cmpb %a0@+, %d3
| dbne %d1, wait_addr_mark_byte
| bne wait_header_init
|
| moveq #max_retry, %d2
|
| amark0: tstb %a2@
| dbmi %d2, amark0
| bpl signal_nonyb
|
| moveb %a3@, %a4@(o_track)
|
| moveq #max_retry, %d2
|
| amark1: tstb %a2@
| dbmi %d2, amark1
| bpl signal_nonyb
|
| moveb %a3@, %a4@(o_side)
|
| moveq #max_retry, %d2
|
| amark2: tstb %a2@
| dbmi %d2, amark2
| bpl signal_nonyb
|
| moveb %a3@, %a4@(o_sector)
|
| moveq #max_retry, %d2
|
| amark3: tstb %a2@
| dbmi %d2, amark3
| bpl signal_nonyb
|
| moveb %a3@, %a4@(o_size)
|
| moveq #max_retry, %d2
|
| crc0: tstb %a2@
| dbmi %d2, crc0
| bpl signal_nonyb
|
| moveb %a3@, %a4@(o_crc0)
|
| moveq #max_retry, %d2
|
| crc1: tstb %a2@
| dbmi %d2, crc1
| bpl signal_nonyb
|
| moveb %a3@, %a4@(o_crc1)
|
| tstb %a3@(read_error - read_mark)
|
| header_exit:
| moveq #0, %d0
| moveb #0x18, %a3@(write_mode0 - read_mark)
| rts
| signal_nonyb:
| moveq #-1, %d0
| moveb #0x18, %a3@(write_mode0 - read_mark)
| rts
|
| .global swim_read_sector_data
| swim_read_sector_data:
| link %a6, #0
| moveml %d1-%d5/%a0-%a5,%sp@-
| movel %a6@(0x0c), %a4
| bsr mfm_read_data
| moveml %sp@+, %d1-%d5/%a0-%a5
| unlk %a6
| rts
|
| mfm_read_data:
| movel %a6@(0x08), %a3
| lea %a3@(read_handshake), %a2
| lea %a3@(read_data), %a5
| lea %a3@(read_mark), %a3
| movew #seek_time, %d2
|
| wait_data_init:
| tstb %a3@(read_error - read_mark)
| moveb #0x18, %a3@(write_mode0 - read_mark)
| moveb #0x01, %a3@(write_mode1 - read_mark)
| moveb #0x01, %a3@(write_mode0 - read_mark)
| tstb %a3@(read_error - read_mark)
| moveb #0x08, %a3@(write_mode1 - read_mark)
|
| lea sector_data_mark, %a0
| moveq #3, %d1
|
| /* wait data address mark */
|
| wait_data_mark_byte:
|
| tstb %a2@
| dbmi %d2, wait_data_mark_byte
| bpl data_exit
|
| moveb %a3@, %d3
| cmpb %a0@+, %d3
| dbne %d1, wait_data_mark_byte
| bne wait_data_init
|
| /* read data */
|
| tstb %a3@(read_error - read_mark)
|
| movel #sector_size-1, %d4 /* sector size */
| read_new_data:
| movew #max_retry, %d2
| read_data_loop:
| moveb %a2@, %d5
| andb #0xc0, %d5
| dbne %d2, read_data_loop
| beq data_exit
| moveb %a5@, %a4@+
| andb #0x40, %d5
| dbne %d4, read_new_data
| beq exit_loop
| moveb %a5@, %a4@+
| dbra %d4, read_new_data
| exit_loop:
|
| /* read CRC */
|
| movew #max_retry, %d2
| data_crc0:
|
| tstb %a2@
| dbmi %d2, data_crc0
| bpl data_exit
|
| moveb %a3@, %d5
|
| moveq #max_retry, %d2
|
| data_crc1:
|
| tstb %a2@
| dbmi %d2, data_crc1
| bpl data_exit
|
| moveb %a3@, %d5
|
| tstb %a3@(read_error - read_mark)
|
| moveb #0x18, %a3@(write_mode0 - read_mark)
|
| /* return number of bytes read */
|
| movel #sector_size, %d0
| addw #1, %d4
| subl %d4, %d0
| rts
| data_exit:
| moveb #0x18, %a3@(write_mode0 - read_mark)
| moveq #-1, %d0
| rts
|
|
