diff options
Diffstat (limited to 'drivers/block/swim_asm.S')
| -rw-r--r-- | drivers/block/swim_asm.S | 243 |
1 files changed, 243 insertions, 0 deletions
diff --git a/drivers/block/swim_asm.S b/drivers/block/swim_asm.S new file mode 100644 index 000000000..3d7a2d875 --- /dev/null +++ b/drivers/block/swim_asm.S @@ -0,0 +1,243 @@ +/* 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 |