//***************************************************************************** // //! Writes a block of data to the transmit buffer and queues it for //! transmission to the USB controller. //! //! \param psBuffer points to the pointer instance into which data is to be //! written. //! \param pucData points to the first byte of data which is to be written. //! \param ulLength is the number of bytes of data to write to the buffer. //! //! This function copies the supplied data into the transmit buffer. The //! transmit buffer data will be packetized according to the constraints //! imposed by the lower layer in use and sent to the USB controller as soon as //! possible. Once a packet is transmitted and acknowledged, a //! \b USB_EVENT_TX_COMPLETE event will be sent to the application callback //! indicating the number of bytes that have been sent from the buffer. //! //! Attempts to send more data than there is space for in the transmit buffer //! will result in fewer bytes than expected being written. The value returned //! by the function indicates the actual number of bytes copied to the buffer. //! //! \return Returns the number of bytes actually written. // //***************************************************************************** unsigned long USBBufferWrite(const tUSBBuffer *psBuffer, const unsigned char *pucData, unsigned long ulLength) { unsigned long ulSpace; tUSBBufferVars *psVars; // // Check parameter validity. // ASSERT(psBuffer && pucData); ASSERT(psBuffer->bTransmitBuffer == true); // // Get our workspace variables. // psVars = psBuffer->pvWorkspace; // // How much space is left in the buffer? // ulSpace = USBRingBufFree(&psVars->sRingBuf); // // How many bytes will we write? // ulLength = (ulLength > ulSpace) ? ulSpace : ulLength; // // Write the data to the buffer. // if(ulLength) { USBRingBufWrite(&psVars->sRingBuf, pucData, ulLength); } // // Try to transmit the next packet to the host. // ScheduleNextTransmission(psBuffer); // // Tell the caller how many bytes we wrote to the buffer. // return(ulLength); }
//***************************************************************************** // //! Writes a block of data to the transmit buffer and queues it for //! transmission to the USB controller. //! //! \param psBuffer points to the pointer instance into which data is to be //! written. //! \param pui8Data points to the first byte of data which is to be written. //! \param ui32Length is the number of bytes of data to write to the buffer. //! //! This function copies the supplied data into the transmit buffer. The //! transmit buffer data will be packetized according to the constraints //! imposed by the lower layer in use and sent to the USB controller as soon as //! possible. Once a packet is transmitted and acknowledged, a //! \b USB_EVENT_TX_COMPLETE event will be sent to the application callback //! indicating the number of bytes that have been sent from the buffer. //! //! Attempts to send more data than there is space for in the transmit buffer //! will result in fewer bytes than expected being written. The value returned //! by the function indicates the actual number of bytes copied to the buffer. //! //! \return Returns the number of bytes actually written. // //***************************************************************************** uint32_t USBBufferWrite(const tUSBBuffer *psBuffer, const uint8_t *pui8Data, uint32_t ui32Length) { uint32_t ui32Space; tUSBBufferVars *psPrivate; // // Check parameter validity. // ASSERT(psBuffer && pui8Data); ASSERT(psBuffer->bTransmitBuffer == true); // // Create a writable pointer to the private data. // psPrivate = &((tUSBBuffer *)psBuffer)->sPrivateData; // // How much space is left in the buffer? // ui32Space = USBRingBufFree(&psPrivate->sRingBuf); // // How many bytes will we write? // ui32Length = (ui32Length > ui32Space) ? ui32Space : ui32Length; // // Write the data to the buffer. // if(ui32Length) { USBRingBufWrite(&psPrivate->sRingBuf, pui8Data, ui32Length); } // // Try to transmit the next packet to the host. // ScheduleNextTransmission((tUSBBuffer *)psBuffer); // // Tell the caller how many bytes we wrote to the buffer. // return(ui32Length); }
//***************************************************************************** // // Handles USB_EVENT_RX_AVAILABLE for a receive buffer. // // \param psBuffer points to the buffer which is receiving the event. // \param ulSize is the size reported in the event. // \param pucData is the pointer provided in the event. // // This function is responsible for reading data from the lower layer into // the buffer or, if we had previously passed a section of the buffer to the // lower layer for it to write into directly, updating the buffer write pointer // to add the new data to the buffer. // // If the pointer provided is NULL, we call the low level pfnTransfer function // to get the new data. If the pointer is not NULL and not within the existing // ring buffer, we copy the data directly from the pointer to the buffer and // return the number of bytes read. // // \return Returns the number of bytes read from the lower layer. // //***************************************************************************** static unsigned long HandleRxAvailable(tUSBBuffer *psBuffer, unsigned long ulSize, unsigned char *pucData) { tUSBBufferVars *psVars; unsigned long ulAvail, ulRead, ulPacket, ulRetCount; // // Get a pointer to our workspace variables. // psVars = psBuffer->pvWorkspace; // // Has the data already been read into memory? // if(pucData) { // // Yes - is it already in our ring buffer? // if((pucData >= psBuffer->pcBuffer) && (pucData < psBuffer->pcBuffer + psBuffer->ulBufferSize)) { // // The data is already in our ring buffer so merely update the // write pointer to add the new data. // USBRingBufAdvanceWrite(&psVars->sRingBuf, ulSize); // // In this case, we pass back 0 to indicate that the lower layer // doesn't need to make any buffer pointer updates. // ulRetCount = 0; } else { // // The data is not within our buffer so we need to copy it into // the buffer. // // How much space does the buffer have available? // ulAvail = USBRingBufFree(&psVars->sRingBuf); // // How much should we copy? // ulRead = (ulAvail < ulSize) ? ulAvail : ulSize; // // Copy the data into the buffer. // USBRingBufWrite(&psVars->sRingBuf, pucData, ulRead); // // We need to return the number of bytes we read in this case // since the buffer supplied to us was owned by the lower layer and // it may need to update its read pointer. // ulRetCount = ulRead; } } else { // // We were passed a NULL pointer so the low level driver has not read // the data into memory yet. We need to call the transfer function to // get the packet. // // How big is the packet that we need to receive? // ulPacket = psBuffer->pfnAvailable(psBuffer->pvHandle); // // How much contiguous space do we have in the buffer? // ulAvail = USBRingBufContigFree(&psVars->sRingBuf); // // Get as much of the packet as we can in the available space. // ulRead = psBuffer->pfnTransfer(psBuffer->pvHandle, (psVars->sRingBuf.pucBuf + psVars->sRingBuf.ulWriteIndex), ulAvail, true); // // Advance the ring buffer write pointer to add our new data. // if(ulRead) { USBRingBufAdvanceWrite(&psVars->sRingBuf, ulRead); } // // Did we get the whole packet? // if(ulRead < ulPacket) { // // No - how much space do we have in the buffer? // ulAvail = USBRingBufContigFree(&psVars->sRingBuf); // // If there is any space left, read as much of the remainder of // the packet as we can. // if(ulAvail) { ulPacket = psBuffer->pfnTransfer(psBuffer->pvHandle, (psVars->sRingBuf.pucBuf + psVars->sRingBuf.ulWriteIndex), ulAvail, true); // // Update the write pointer after we read more data into the // buffer. // if(ulPacket) { USBRingBufAdvanceWrite(&psVars->sRingBuf, ulPacket); } } } // // We need to return 0 in this case to indicate that the lower layer // need not perform any buffer maintenance as a result of the callback. // ulRetCount = 0; } // // How much data do we have in the buffer? // ulAvail = USBRingBufUsed(&psVars->sRingBuf); // // Pass the event on to the client with the current read pointer and // available data size. The client is expected to understand the ring // structure and be able to deal with wrap if it wants to read the data // directly from the buffer. // ulRead = psBuffer->pfnCallback(psBuffer->pvCBData, USB_EVENT_RX_AVAILABLE, ulAvail, (psVars->sRingBuf.pucBuf + psVars->sRingBuf.ulReadIndex)); // // If the client read anything from the buffer, update the read pointer. // USBRingBufAdvanceRead(&psVars->sRingBuf, ulRead); // // Return the correct value to the low level driver. // return(ulRetCount); }