mirror of
https://github.com/raphnet/dreamcast_usb
synced 2024-11-18 15:05:02 -05:00
188 lines
7.8 KiB
PHP
188 lines
7.8 KiB
PHP
/* Name: asmcommon.inc
|
|
* Project: V-USB, virtual USB port for Atmel's(r) AVR(r) microcontrollers
|
|
* Author: Christian Starkjohann
|
|
* Creation Date: 2007-11-05
|
|
* Tabsize: 4
|
|
* Copyright: (c) 2007 by OBJECTIVE DEVELOPMENT Software GmbH
|
|
* License: GNU GPL v2 (see License.txt), GNU GPL v3 or proprietary (CommercialLicense.txt)
|
|
*/
|
|
|
|
/* Do not link this file! Link usbdrvasm.S instead, which includes the
|
|
* appropriate implementation!
|
|
*/
|
|
|
|
/*
|
|
General Description:
|
|
This file contains assembler code which is shared among the USB driver
|
|
implementations for different CPU cocks. Since the code must be inserted
|
|
in the middle of the module, it's split out into this file and #included.
|
|
|
|
Jump destinations called from outside:
|
|
sofError: Called when no start sequence was found.
|
|
se0: Called when a package has been successfully received.
|
|
overflow: Called when receive buffer overflows.
|
|
doReturn: Called after sending data.
|
|
|
|
Outside jump destinations used by this module:
|
|
waitForJ: Called to receive an already arriving packet.
|
|
sendAckAndReti:
|
|
sendNakAndReti:
|
|
sendCntAndReti:
|
|
usbSendAndReti:
|
|
|
|
The following macros must be defined before this file is included:
|
|
.macro POP_STANDARD
|
|
.endm
|
|
.macro POP_RETI
|
|
.endm
|
|
*/
|
|
|
|
#define token x1
|
|
|
|
overflow:
|
|
ldi x2, 1<<USB_INTR_PENDING_BIT
|
|
USB_STORE_PENDING(x2) ; clear any pending interrupts
|
|
ignorePacket:
|
|
clr token
|
|
rjmp storeTokenAndReturn
|
|
|
|
;----------------------------------------------------------------------------
|
|
; Processing of received packet (numbers in brackets are cycles after center of SE0)
|
|
;----------------------------------------------------------------------------
|
|
;This is the only non-error exit point for the software receiver loop
|
|
;we don't check any CRCs here because there is no time left.
|
|
se0:
|
|
subi cnt, USB_BUFSIZE ;[5]
|
|
neg cnt ;[6]
|
|
sub YL, cnt ;[7]
|
|
sbci YH, 0 ;[8]
|
|
ldi x2, 1<<USB_INTR_PENDING_BIT ;[9]
|
|
USB_STORE_PENDING(x2) ;[10] clear pending intr and check flag later. SE0 should be over.
|
|
ld token, y ;[11]
|
|
cpi token, USBPID_DATA0 ;[13]
|
|
breq handleData ;[14]
|
|
cpi token, USBPID_DATA1 ;[15]
|
|
breq handleData ;[16]
|
|
lds shift, usbDeviceAddr;[17]
|
|
ldd x2, y+1 ;[19] ADDR and 1 bit endpoint number
|
|
lsl x2 ;[21] shift out 1 bit endpoint number
|
|
cpse x2, shift ;[22]
|
|
rjmp ignorePacket ;[23]
|
|
/* only compute endpoint number in x3 if required later */
|
|
#if USB_CFG_HAVE_INTRIN_ENDPOINT || USB_CFG_IMPLEMENT_FN_WRITEOUT
|
|
ldd x3, y+2 ;[24] endpoint number + crc
|
|
rol x3 ;[26] shift in LSB of endpoint
|
|
#endif
|
|
cpi token, USBPID_IN ;[27]
|
|
breq handleIn ;[28]
|
|
cpi token, USBPID_SETUP ;[29]
|
|
breq handleSetupOrOut ;[30]
|
|
cpi token, USBPID_OUT ;[31]
|
|
brne ignorePacket ;[32] must be ack, nak or whatever
|
|
; rjmp handleSetupOrOut ; fallthrough
|
|
|
|
;Setup and Out are followed by a data packet two bit times (16 cycles) after
|
|
;the end of SE0. The sync code allows up to 40 cycles delay from the start of
|
|
;the sync pattern until the first bit is sampled. That's a total of 56 cycles.
|
|
handleSetupOrOut: ;[32]
|
|
#if USB_CFG_IMPLEMENT_FN_WRITEOUT /* if we have data for endpoint != 0, set usbCurrentTok to address */
|
|
andi x3, 0xf ;[32]
|
|
breq storeTokenAndReturn ;[33]
|
|
mov token, x3 ;[34] indicate that this is endpoint x OUT
|
|
#endif
|
|
storeTokenAndReturn:
|
|
sts usbCurrentTok, token;[35]
|
|
doReturn:
|
|
POP_STANDARD ;[37] 12...16 cycles
|
|
USB_LOAD_PENDING(YL) ;[49]
|
|
sbrc YL, USB_INTR_PENDING_BIT;[50] check whether data is already arriving
|
|
rjmp waitForJ ;[51] save the pops and pushes -- a new interrupt is already pending
|
|
sofError:
|
|
POP_RETI ;macro call
|
|
reti
|
|
|
|
handleData:
|
|
#if USB_CFG_CHECK_CRC
|
|
CRC_CLEANUP_AND_CHECK ; jumps to ignorePacket if CRC error
|
|
#endif
|
|
lds shift, usbCurrentTok;[18]
|
|
tst shift ;[20]
|
|
breq doReturn ;[21]
|
|
lds x2, usbRxLen ;[22]
|
|
tst x2 ;[24]
|
|
brne sendNakAndReti ;[25]
|
|
; 2006-03-11: The following two lines fix a problem where the device was not
|
|
; recognized if usbPoll() was called less frequently than once every 4 ms.
|
|
cpi cnt, 4 ;[26] zero sized data packets are status phase only -- ignore and ack
|
|
brmi sendAckAndReti ;[27] keep rx buffer clean -- we must not NAK next SETUP
|
|
#if USB_CFG_CHECK_DATA_TOGGLING
|
|
sts usbCurrentDataToken, token ; store for checking by C code
|
|
#endif
|
|
sts usbRxLen, cnt ;[28] store received data, swap buffers
|
|
sts usbRxToken, shift ;[30]
|
|
lds x2, usbInputBufOffset;[32] swap buffers
|
|
ldi cnt, USB_BUFSIZE ;[34]
|
|
sub cnt, x2 ;[35]
|
|
sts usbInputBufOffset, cnt;[36] buffers now swapped
|
|
rjmp sendAckAndReti ;[38] 40 + 17 = 57 until SOP
|
|
|
|
handleIn:
|
|
;We don't send any data as long as the C code has not processed the current
|
|
;input data and potentially updated the output data. That's more efficient
|
|
;in terms of code size than clearing the tx buffers when a packet is received.
|
|
lds x1, usbRxLen ;[30]
|
|
cpi x1, 1 ;[32] negative values are flow control, 0 means "buffer free"
|
|
brge sendNakAndReti ;[33] unprocessed input packet?
|
|
ldi x1, USBPID_NAK ;[34] prepare value for usbTxLen
|
|
#if USB_CFG_HAVE_INTRIN_ENDPOINT
|
|
andi x3, 0xf ;[35] x3 contains endpoint
|
|
#if USB_CFG_SUPPRESS_INTR_CODE
|
|
brne sendNakAndReti ;[36]
|
|
#else
|
|
brne handleIn1 ;[36]
|
|
#endif
|
|
#endif
|
|
lds cnt, usbTxLen ;[37]
|
|
sbrc cnt, 4 ;[39] all handshake tokens have bit 4 set
|
|
rjmp sendCntAndReti ;[40] 42 + 16 = 58 until SOP
|
|
sts usbTxLen, x1 ;[41] x1 == USBPID_NAK from above
|
|
ldi YL, lo8(usbTxBuf) ;[43]
|
|
ldi YH, hi8(usbTxBuf) ;[44]
|
|
rjmp usbSendAndReti ;[45] 57 + 12 = 59 until SOP
|
|
|
|
; Comment about when to set usbTxLen to USBPID_NAK:
|
|
; We should set it back when we receive the ACK from the host. This would
|
|
; be simple to implement: One static variable which stores whether the last
|
|
; tx was for endpoint 0 or 1 and a compare in the receiver to distinguish the
|
|
; ACK. However, we set it back immediately when we send the package,
|
|
; assuming that no error occurs and the host sends an ACK. We save one byte
|
|
; RAM this way and avoid potential problems with endless retries. The rest of
|
|
; the driver assumes error-free transfers anyway.
|
|
|
|
#if !USB_CFG_SUPPRESS_INTR_CODE && USB_CFG_HAVE_INTRIN_ENDPOINT /* placed here due to relative jump range */
|
|
handleIn1: ;[38]
|
|
#if USB_CFG_HAVE_INTRIN_ENDPOINT3
|
|
; 2006-06-10 as suggested by O.Tamura: support second INTR IN / BULK IN endpoint
|
|
cpi x3, USB_CFG_EP3_NUMBER;[38]
|
|
breq handleIn3 ;[39]
|
|
#endif
|
|
lds cnt, usbTxLen1 ;[40]
|
|
sbrc cnt, 4 ;[42] all handshake tokens have bit 4 set
|
|
rjmp sendCntAndReti ;[43] 47 + 16 = 63 until SOP
|
|
sts usbTxLen1, x1 ;[44] x1 == USBPID_NAK from above
|
|
ldi YL, lo8(usbTxBuf1) ;[46]
|
|
ldi YH, hi8(usbTxBuf1) ;[47]
|
|
rjmp usbSendAndReti ;[48] 50 + 12 = 62 until SOP
|
|
|
|
#if USB_CFG_HAVE_INTRIN_ENDPOINT3
|
|
handleIn3:
|
|
lds cnt, usbTxLen3 ;[41]
|
|
sbrc cnt, 4 ;[43]
|
|
rjmp sendCntAndReti ;[44] 49 + 16 = 65 until SOP
|
|
sts usbTxLen3, x1 ;[45] x1 == USBPID_NAK from above
|
|
ldi YL, lo8(usbTxBuf3) ;[47]
|
|
ldi YH, hi8(usbTxBuf3) ;[48]
|
|
rjmp usbSendAndReti ;[49] 51 + 12 = 63 until SOP
|
|
#endif
|
|
#endif
|