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VCP HAL transmit buffer fixes

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Fixes issues that could cause the tail of the ring buffer to be moved before data transmission is complete thus allowing the head to overwrite unsent data. Also adds 512 byte blocking when queueing the output data with the endpoint (helps with slow receivers).

Fixes a bug in the transmit buffer logic if the TX and RX buffers were different sizes.
This commit is contained in:
Bruce Luckcuck 2019-02-09 21:00:10 -05:00
parent ca98ee7df0
commit 620a3c3be4
2 changed files with 36 additions and 30 deletions
Download patch file Download diff file Expand all files Collapse all files

64
src/main/vcp_hal/usbd_cdc_interface.c
View file

@ -61,6 +61,8 @@
#define APP_RX_DATA_SIZE 2048
#define APP_TX_DATA_SIZE 2048
#define APP_TX_BLOCK_SIZE 512
/* Private macro -------------------------------------------------------------*/
/* Private variables ---------------------------------------------------------*/
USBD_CDC_LineCodingTypeDef LineCoding =
@ -241,35 +243,42 @@ static int8_t CDC_Itf_Control (uint8_t cmd, uint8_t* pbuf, uint16_t length)
*/
void HAL_TIM_PeriodElapsedCallback(TIM_HandleTypeDef *htim)
{
if (htim->Instance != TIMusb) return;
if (htim->Instance != TIMusb) {
return;
}
uint32_t buffptr;
uint32_t buffsize;
static uint32_t lastBuffsize = 0;
if (UserTxBufPtrOut != UserTxBufPtrIn)
{
if (UserTxBufPtrOut > UserTxBufPtrIn) /* Roll-back */
{
buffsize = APP_RX_DATA_SIZE - UserTxBufPtrOut;
}
else
{
buffsize = UserTxBufPtrIn - UserTxBufPtrOut;
}
USBD_CDC_HandleTypeDef *hcdc = (USBD_CDC_HandleTypeDef*)USBD_Device.pCDC_ClassData;
buffptr = UserTxBufPtrOut;
USBD_CDC_SetTxBuffer(&USBD_Device, (uint8_t*)&UserTxBuffer[buffptr], buffsize);
if (USBD_CDC_TransmitPacket(&USBD_Device) == USBD_OK)
{
UserTxBufPtrOut += buffsize;
if (UserTxBufPtrOut == APP_TX_DATA_SIZE)
{
if (hcdc->TxState == 0) {
// endpoint has finished transmitting previous block
if (lastBuffsize) {
// move the ring buffer tail based on the previous succesful transmission
UserTxBufPtrOut += lastBuffsize;
if (UserTxBufPtrOut == APP_TX_DATA_SIZE) {
UserTxBufPtrOut = 0;
}
lastBuffsize = 0;
}
}
if (UserTxBufPtrOut != UserTxBufPtrIn) {
if (UserTxBufPtrOut > UserTxBufPtrIn) { /* Roll-back */
buffsize = APP_TX_DATA_SIZE - UserTxBufPtrOut;
} else {
buffsize = UserTxBufPtrIn - UserTxBufPtrOut;
}
if (buffsize > APP_TX_BLOCK_SIZE) {
buffsize = APP_TX_BLOCK_SIZE;
}
USBD_CDC_SetTxBuffer(&USBD_Device, (uint8_t*)&UserTxBuffer[UserTxBufPtrOut], buffsize);
if (USBD_CDC_TransmitPacket(&USBD_Device) == USBD_OK) {
lastBuffsize = buffsize;
}
}
}
}
/**
@ -379,16 +388,13 @@ uint32_t CDC_Send_FreeBytes(void)
*/
uint32_t CDC_Send_DATA(const uint8_t *ptrBuffer, uint32_t sendLength)
{
USBD_CDC_HandleTypeDef *hcdc = (USBD_CDC_HandleTypeDef*)USBD_Device.pCDC_ClassData;
while (hcdc->TxState != 0);
for (uint32_t i = 0; i < sendLength; i++)
{
UserTxBuffer[UserTxBufPtrIn] = ptrBuffer[i];
UserTxBufPtrIn = (UserTxBufPtrIn + 1) % APP_TX_DATA_SIZE;
for (uint32_t i = 0; i < sendLength; i++) {
while (CDC_Send_FreeBytes() == 0) {
// block until there is free space in the ring buffer
delay(1);
}
UserTxBuffer[UserTxBufPtrIn] = ptrBuffer[i];
UserTxBufPtrIn = (UserTxBufPtrIn + 1) % APP_TX_DATA_SIZE;
}
return sendLength;
}

2
src/main/vcp_hal/usbd_cdc_interface.h
View file

@ -65,7 +65,7 @@
/* Periodically, the state of the buffer "UserTxBuffer" is checked.
The period depends on CDC_POLLING_INTERVAL */
#define CDC_POLLING_INTERVAL 10 /* in ms. The max is 65 and the min is 1 */
#define CDC_POLLING_INTERVAL 5 /* in ms. The max is 65 and the min is 1 */
/* Exported typef ------------------------------------------------------------*/
/* The following structures groups all needed parameters to be configured for the