osd-contiki/cpu/6502/net/lan91c96.S
Oliver Schmidt a5d7a06027 Enhanced Ethernet drivers.
Made Ethernet drivers easier to consume by assembly programs.
* Replaced function pointers with JMP instructions.
* Provide return values additionally via Carry flag.

Reset Ethernet chips on initialization.
Both for the CS8900A and the W5100 the data sheets just say that
the RESET bit is automatically cleared after the RESET. This may
be interpreted in two ways:
1) There's no need to be afraid of reading the RESET bit as 1 and
unintentionally trigger a RESET by writing it back after ORing in
some other bit.
2) The RESET process isn't complete before the RESET bit hasn't
become 0 again.
It's impossible for me to empirically falsify the latter option
as the drivers are supposed to work on faster machines than the
ones I have access to. And if the RESET process includes things
like oscillators then the time to complete the RESET could differ
even between multiple exemplars of the same chip. Therefore I
opted to presume the latter option.
However that means a non-exsistent chip may cause an infinite
loop while waiting for the RESET bit to be cleared so I finally
added code to detect the presence of the Ethernet chips. There's
a risk of a chip being locked up in a way that makes the detection
fail - and therefore the RESET not being performed. This catch-22
needs to be solved by the user doing a hard RESET.
2014-06-12 22:56:35 +02:00

427 lines
9.7 KiB
ArmAsm

;
; Copyright (c) 2003-2007, Adam Dunkels, Josef Soucek and Oliver Schmidt
; All rights reserved.
;
; Redistribution and use in source and binary forms, with or without
; modification, are permitted provided that the following conditions
; are met:
; 1. Redistributions of source code must retain the above copyright
; notice, this list of conditions and the following disclaimer.
; 2. Redistributions in binary form must reproduce the above copyright
; notice, this list of conditions and the following disclaimer in the
; documentation and/or other materials provided with the distribution.
; 3. Neither the name of the Institute nor the names of its contributors
; may be used to endorse or promote products derived from this software
; without specific prior written permission.
;
; THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
; ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
; IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
; ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
; FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
; DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
; OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
; HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
; LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
; OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
; SUCH DAMAGE.
;
; This file is part of the Contiki operating system.
;
; Author: Adam Dunkels <adam@sics.se>, Josef Soucek <josef.soucek@ide64.org>,
; Oliver Schmidt <ol.sc@web.de>
;
;---------------------------------------------------------------------
.macpack module
module_header _lan91c96
; Driver signature
.byte $65, $74, $68 ; "eth"
.byte $01 ; Ethernet driver API version number
; Ethernet address
mac: .byte $00, $80, $0F ; OUI of Standard Microsystems
.byte $11, $11, $11
; Buffer attributes
bufaddr:.res 2 ; Address
bufsize:.res 2 ; Size
; Jump table.
jmp init
jmp poll
jmp send
jmp exit
;---------------------------------------------------------------------
.if DYN_DRV
.zeropage
sp: .res 2 ; Stack pointer (Do not trash !)
reg: .res 2 ; Address of register base
ptr: .res 2 ; Indirect addressing pointer
len: .res 2 ; Frame length
.else
.include "zeropage.inc"
reg := ptr1 ; Address of register base
ptr := ptr2 ; Indirect addressing pointer
len := ptr3 ; Frame length
.endif
;---------------------------------------------------------------------
.rodata
fixup: .byte fixup02-fixup01, fixup03-fixup02, fixup04-fixup03
.byte fixup05-fixup04, fixup06-fixup05, fixup07-fixup06
.byte fixup08-fixup07, fixup09-fixup08, fixup10-fixup09
.byte fixup11-fixup10, fixup12-fixup11, fixup13-fixup12
.byte fixup14-fixup13, fixup15-fixup14, fixup16-fixup15
.byte fixup17-fixup16, fixup18-fixup17, fixup19-fixup18
.byte fixup20-fixup19, fixup21-fixup20, fixup22-fixup21
.byte fixup23-fixup22, fixup24-fixup23, fixup25-fixup24
.byte fixup26-fixup25, fixup27-fixup26, fixup28-fixup27
.byte fixup29-fixup28, fixup30-fixup29, fixup31-fixup30
.byte fixup32-fixup31, fixup33-fixup32, fixup34-fixup33
.byte fixup35-fixup34, fixup36-fixup35, fixup37-fixup36
.byte fixup38-fixup37, fixup39-fixup38, fixup40-fixup39
fixups = * - fixup
;---------------------------------------------------------------------
ethbsr := $FF0E ; Bank select register R/W (2B)
; Register bank 0
ethtcr := $FF00 ; Transmition control register R/W (2B)
ethephsr := $FF02 ; EPH status register R/O (2B)
ethrcr := $FF04 ; Receive control register R/W (2B)
ethecr := $FF06 ; Counter register R/O (2B)
ethmir := $FF08 ; Memory information register R/O (2B)
ethmcr := $FF0A ; Memory Config. reg. +0 R/W +1 R/O (2B)
; Register bank 1
ethcr := $FF00 ; Configuration register R/W (2B)
ethbar := $FF02 ; Base address register R/W (2B)
ethiar := $FF04 ; Individual address register R/W (6B)
ethgpr := $FF0A ; General address register R/W (2B)
ethctr := $FF0C ; Control register R/W (2B)
; Register bank 2
ethmmucr := $FF00 ; MMU command register W/O (1B)
ethautotx := $FF01 ; AUTO TX start register R/W (1B)
ethpnr := $FF02 ; Packet number register R/W (1B)
etharr := $FF03 ; Allocation result register R/O (1B)
ethfifo := $FF04 ; FIFO ports register R/O (2B)
ethptr := $FF06 ; Pointer register R/W (2B)
ethdata := $FF08 ; Data register R/W (4B)
ethist := $FF0C ; Interrupt status register R/O (1B)
ethack := $FF0C ; Interrupt acknowledge register W/O (1B)
ethmsk := $FF0D ; Interrupt mask register R/W (1B)
; Register bank 3
ethmt := $FF00 ; Multicast table R/W (8B)
ethmgmt := $FF08 ; Management interface R/W (2B)
ethrev := $FF0A ; Revision register R/W (2B)
ethercv := $FF0C ; Early RCV register R/W (2B)
.data
;---------------------------------------------------------------------
init:
; Save address of register base
sta reg
stx reg+1
; Start with first fixup location
lda #<(fixup01+1)
ldx #>(fixup01+1)
sta ptr
stx ptr+1
ldx #$FF
ldy #$00
; Fixup address at location
: lda reg
ora (ptr),y
sta (ptr),y
iny
lda reg+1
sta (ptr),y
dey
; Advance to next fixup location
inx
cpx #fixups
bcs :+
lda ptr
clc
adc fixup,x
sta ptr
bcc :-
inc ptr+1
bcs :- ; Always
; Reset ETH card
: lda #$00 ; Bank 0
fixup01:sta ethbsr
lda #%10000000 ; Software reset
fixup02:sta ethrcr+1
ldy #$00
fixup03:sty ethrcr
fixup04:sty ethrcr+1
; Delay
: cmp ($FF,x) ; 6 cycles
cmp ($FF,x) ; 6 cycles
iny ; 2 cycles
bne :- ; 3 cycles
; 17 * 256 = 4352 -> 4,4 ms
; Enable transmit and receive
lda #%10000001 ; Enable transmit TXENA, PAD_EN
ldx #%00000011 ; Enable receive, strip CRC ???
fixup05:sta ethtcr
fixup06:stx ethrcr+1
lda #$01 ; Bank 1
fixup07:sta ethbsr
; Check ISA mode base address register for reset values
lda #$18^67 ; I/O base $300 + ROM $CC000
fixup08:eor ethbar
fixup09:eor ethbar+1
beq :+
sec
rts
:
fixup10:lda ethcr+1
ora #%00010000 ; No wait (IOCHRDY)
fixup11:sta ethcr+1
lda #%00001001 ; Auto release
fixup12:sta ethctr+1
; Set MAC address
ldy #$00
: lda mac,y
fixup13:sta ethiar,y
iny
cpy #$06
bcc :-
; Set interrupt mask
lda #$02 ; Bank 2
fixup14:sta ethbsr
lda #%00000000 ; No interrupts
fixup15:sta ethmsk
tax
clc
rts
;---------------------------------------------------------------------
poll:
fixup16:lda ethist
and #%00000001 ; RCV INT
beq :+
; Process the incoming packet
; ---------------------------
lda #$00
ldx #%11100000 ; RCV, AUTO INCR., READ
fixup17:sta ethptr
fixup18:stx ethptr+1
; Last word contains 'last data byte' and $60 or 'fill byte' and $40
fixup19:lda ethdata ; Status word
fixup20:lda ethdata ; Need high byte only
; Move ODDFRM bit into carry:
; - Even packet length -> carry clear -> subtract 6 bytes
; - Odd packet length -> carry set -> subtract 5 bytes
lsr
lsr
lsr
lsr
lsr
; The packet contains 3 extra words
fixup21:lda ethdata ; Total number of bytes
sbc #$05 ; Actually 5 or 6 depending on carry
sta len
fixup22:lda ethdata
sbc #$00
sta len+1
; Is bufsize < len ?
lda bufsize
cmp len
lda bufsize+1
sbc len+1
bcs :++
; Yes, skip packet
; Remove and release RX packet from the FIFO
lda #%10000000
fixup23:sta ethmmucr
; No packet available
lda #$00
: tax
sec
rts
; Read bytes into buffer
: jsr adjustptr
:
fixup24:lda ethdata
sta (ptr),y
iny
bne :-
inc ptr+1
dex
bpl :-
; Remove and release RX packet from the FIFO
lda #%10000000
fixup25:sta ethmmucr
; Return packet length
lda len
ldx len+1
clc
rts
;---------------------------------------------------------------------
send:
; Save packet length
sta len
stx len+1
; Allocate memory for TX
txa
ora #%00100000
fixup26:sta ethmmucr
; 8 retries
ldy #$08
; Wait for allocation ready
:
fixup27:lda ethist
and #%00001000 ; ALLOC INT
bne :+
; Shouldn't we do something here to actively free memory,
; maybe removing and releasing an RX packet from the FIFO ???
; And try again
dey
bne :-
sec
rts
; Acknowledge interrupt, is it necessary ???
: lda #%00001000
fixup28:sta ethack
; Set packet address
fixup29:lda etharr
fixup30:sta ethpnr
lda #$00
ldx #%01000000 ; AUTO INCR.
fixup31:sta ethptr
fixup32:stx ethptr+1
; Status written by CSMA
lda #$00
fixup33:sta ethdata
fixup34:sta ethdata
; Check packet length parity:
; - Even packet length -> carry set -> add 6 bytes
; - Odd packet length -> carry clear -> add 5 bytes
lda len
eor #$01
lsr
; The packet contains 3 extra words
lda len
adc #$05 ; Actually 5 or 6 depending on carry
fixup35:sta ethdata
lda len+1
adc #$00
fixup36:sta ethdata
; Send the packet
; ---------------
; Write bytes from buffer
jsr adjustptr
: lda (ptr),y
fixup37:sta ethdata
iny
bne :-
inc ptr+1
dex
bpl :-
; Odd packet length ?
lda len
lsr
bcc :+
; Yes
lda #%00100000 ; ODD
bne :++ ; Always
; No
: lda #$00
fixup38:sta ethdata ; Fill byte
:
fixup39:sta ethdata ; Control byte
; Add packet to FIFO
lda #%11000000 ; ENQUEUE PACKET - transmit packet
fixup40:sta ethmmucr
clc
rts
;---------------------------------------------------------------------
exit:
rts
;---------------------------------------------------------------------
adjustptr:
lda len
ldx len+1
eor #$FF ; Two's complement part 1
tay
iny ; Two's complement part 2
sty reg
sec
lda bufaddr
sbc reg
sta ptr
lda bufaddr+1
sbc #$00
sta ptr+1
rts
;---------------------------------------------------------------------