diff options
| -rw-r--r-- | libmaple/usb/usb.c | 102 | ||||
| -rw-r--r-- | libmaple/usb/usb.h | 4 |
2 files changed, 56 insertions, 50 deletions
diff --git a/libmaple/usb/usb.c b/libmaple/usb/usb.c index 8dbf9c9..6c010d9 100644 --- a/libmaple/usb/usb.c +++ b/libmaple/usb/usb.c @@ -225,10 +225,11 @@ RESULT usbPowerOff(void) { return USB_SUCCESS; } + +// These two functions (usbEnbISR/usbDsbISR) are implementented in ST style, +// and at least the DsbISR doesn't seem to work? void usbEnbISR(void) { NVIC_InitTypeDef NVIC_InitStructure; - - NVIC_InitStructure.NVIC_IRQChannel = USB_LP_IRQ; NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0; NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0; @@ -339,64 +340,62 @@ void usbWaitReset(void) { systemHardReset(); } - -/* todo, change this function to behave like below */ -/* copies data out of sendBuf into the packet memory for - usb, but waits until any previous usb transmissions have - completed before doing this. It returns without waiting - for its data to be sent. most efficient when 64 bytes are copied - at a time. users responsible for not overflowing sendbuf - with len! if > 64 bytes are being sent, then the function - will simply send the first 64 and return. It is the USERS JOB - to implement any blocking. return -1 implies connection failure, - return 0 implies buffer filled, return < len implies another - transaction is needed to complete the send. -*/ - -/* current behavior: - sendBytes will block until bytes are actually sent over the pipe. - broken pipes could stall this function. DTR and RTS are used to check - for a valid connection. - */ -int16 usbSendBytes(uint8* sendBuf, uint16 len) { +/* This low-level send bytes function is NON-BLOCKING; blocking behavior, with + * a timeout, is implemented in usercode (or in the Wirish C++ high level + * implementation). + * + * This function will quickly copy up to 64 bytes of data (out of an + * arbitrarily large buffer) into the USB peripheral TX buffer and return the + * number placed in that buffer. It is up to usercode to divide larger packets + * into 64-byte chunks to guarantee delivery. Use usbGetCountTx() to determine + * whether the bytes were ACTUALLY recieved by the host or just transfered to + * the buffer. + * + * The function will return -1 if it doesn't think that the USB host is + * "connected", but it can't detect this state robustly. "Connected" in this + * context means that an actual program on the Host operating system is + * connected to the virtual COM/ttyACM device and is recieving the bytes; the + * Host operating system is almost always configured and keeping this endpoint + * alive, but the bytes never get read out of the endpoint buffer. + * + * The behavior of this function is subtle and frustrating; it has gone through + * many simpler and cleaner implementation that frustratingly don't work cross + * platform. + * + * */ +uint16 usbSendBytes(uint8* sendBuf, uint16 len) { + + uint16 loaded = 0; if (bDeviceState != CONFIGURED || (!usbGetDTR() && !usbGetRTS())) { - return -1; /* indicates to caller to stop trying, were not connected */ + // Indicates to caller to stop trying, were not configured/connected + // The DTR and RTS lines are handled differently on major platforms, so + // the above logic is unreliable + return 0; } - /* - if (countTx >= VCOM_TX_EPSIZE) { - return 0; // indicates to caller that the buffer is full + // Due to a variety of shit this is how we roll; all buffering etc is pushed + // upstream + if (countTx) { + return 0; } - */ - while (countTx) - ; - - uint16 sent = len; - - while (len > VCOM_TX_EPSIZE) { - countTx = VCOM_TX_EPSIZE; - - UserToPMABufferCopy(sendBuf,VCOM_TX_ADDR,VCOM_TX_EPSIZE); - _SetEPTxCount(VCOM_TX_ENDP, VCOM_TX_EPSIZE); - _SetEPTxValid(VCOM_TX_ENDP); - - while (countTx) - ; - - len -= VCOM_TX_EPSIZE; - sendBuf += VCOM_TX_EPSIZE; + // We can only put VCOM_TX_EPSIZE bytes in the buffer + if(len > VCOM_TX_EPSIZE) { + loaded = VCOM_TX_EPSIZE; + } else { + loaded = len; } - if (len != 0) { - countTx = len; - UserToPMABufferCopy(sendBuf,VCOM_TX_ADDR,len); - _SetEPTxCount(VCOM_TX_ENDP,len); + // Try to load some bytes if we can + if (loaded) { + UserToPMABufferCopy(sendBuf,VCOM_TX_ADDR + countTx, loaded); + _SetEPTxCount(VCOM_TX_ENDP, countTx+loaded); _SetEPTxValid(VCOM_TX_ENDP); + countTx += loaded; } - return sent; + return loaded; } /* returns the number of available bytes are in the recv FIFO */ @@ -453,3 +452,8 @@ uint8 usbGetDTR() { uint8 usbGetRTS() { return ((line_dtr_rts & CONTROL_LINE_RTS) != 0); } + +uint16 usbGetPending() { + return countTx; +} + diff --git a/libmaple/usb/usb.h b/libmaple/usb/usb.h index 6451f7e..66e820c 100644 --- a/libmaple/usb/usb.h +++ b/libmaple/usb/usb.h @@ -51,14 +51,16 @@ typedef enum void usbWaitReset(void); /* blocking functions for send/receive */ - int16 usbSendBytes(uint8* sendBuf,uint16 len); + uint16 usbSendBytes(uint8* sendBuf,uint16 len); uint8 usbBytesAvailable(void); uint8 usbReceiveBytes(uint8* recvBuf, uint8 len); uint8 usbGetDTR(void); uint8 usbGetRTS(void); + uint16 usbGetPending(void); void usbSendHello(void); + #ifdef __cplusplus } // extern "C" #endif |