diff options
Diffstat (limited to 'usbdrv/asmcommon.inc')
| -rw-r--r-- | usbdrv/asmcommon.inc | 187 |
1 files changed, 187 insertions, 0 deletions
diff --git a/usbdrv/asmcommon.inc b/usbdrv/asmcommon.inc new file mode 100644 index 0000000..d2a4f7c --- /dev/null +++ b/usbdrv/asmcommon.inc @@ -0,0 +1,187 @@ +/* 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 |