X-Git-Url: http://git.linex4red.de/pub/USBasp.git/blobdiff_plain/6ffa080eb257892c7cad9f80f8bfef99b4896082..39f1c0c136520a3f4746ad6381d1242979125ff3:/firmware/usbdrv/asmcommon.inc

diff --git a/firmware/usbdrv/asmcommon.inc b/firmware/usbdrv/asmcommon.inc
new file mode 100644
index 000000000..1af53b8ba
--- /dev/null
+++ b/firmware/usbdrv/asmcommon.inc
@@ -0,0 +1,185 @@
+/* Name: asmcommon.inc
+ * Project: AVR USB driver
+ * 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)
+ * Revision: $Id$
+ */
+
+/* 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:
+    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