/**
* Should allocate a pbuf and transfer the bytes of the incoming
* packet from the interface into the pbuf.
*
* @param pxNetIf the lwip network interface structure for this etherpxNetIf
* @return a pbuf filled with the received packet (including MAC header)
* NULL on memory error
*/
static struct pbuf *prvLowLevelInput( void )
{
struct pbuf *p = NULL, *q;
const uint32_t ulCRCLength = 4UL;
uint32_t ulDataLength;
extern uint8_t *EMAC_NextPacketToRead( void );
uint8_t *pucReceivedData;
/* Obtain the length, minus the CRC. The CRC is four bytes
but the length is already minus 1. */
ulDataLength = EMAC_GetReceiveDataSize() - ( ulCRCLength - 1UL );
if( ulDataLength > 0U )
{
#if ETH_PAD_SIZE
len += ETH_PAD_SIZE; /* allow room for Ethernet padding */
#endif
/* Allocate a pbuf chain of pbufs from the pool. */
p = pbuf_alloc( PBUF_RAW, ulDataLength, PBUF_POOL );
if( p != NULL )
{
#if ETH_PAD_SIZE
pbuf_header( p, -ETH_PAD_SIZE ); /* drop the padding word */
#endif
/* Iterate over the pbuf chain until we have read the entire
packet into the pbuf. */
ulDataLength = 0UL;
pucReceivedData = EMAC_NextPacketToRead();
for( q = p; q != NULL; q = q->next )
{
/* Read enough bytes to fill this pbuf in the chain. The
available data in the pbuf is given by the q->len variable.
This does not necessarily have to be a memcpy, you can also preallocate
pbufs for a DMA-enabled MAC and after receiving truncate it to the
actually received size. In this case, ensure the usTotalLength member of the
pbuf is the sum of the chained pbuf len members. */
memcpy( q->payload, &( pucReceivedData[ ulDataLength ] ), q->len );
ulDataLength += q->len;
}
#if ETH_PAD_SIZE
pbuf_header( p, ETH_PAD_SIZE ); /* reclaim the padding word */
#endif
LINK_STATS_INC( link.recv );
}
}
return p;
}
static void prvEMACHandlerTask( void *pvParameters )
{
size_t xDataLength;
const uint16_t usCRCLength = 4;
xNetworkBufferDescriptor_t *pxNetworkBuffer;
xIPStackEvent_t xRxEvent = { eEthernetRxEvent, NULL };
/* This is not included in the header file for some reason. */
extern uint8_t *EMAC_NextPacketToRead( void );
( void ) pvParameters;
configASSERT( xEMACRxEventSemaphore );
for( ;; )
{
/* Wait for the EMAC interrupt to indicate that another packet has been
received. The while() loop is only needed if INCLUDE_vTaskSuspend is
set to 0 in FreeRTOSConfig.h. */
while( xSemaphoreTake( xEMACRxEventSemaphore, portMAX_DELAY ) == pdFALSE );
/* At least one packet has been received. */
while( EMAC_CheckReceiveIndex() != FALSE )
{
/* Obtain the length, minus the CRC. The CRC is four bytes
but the length is already minus 1. */
xDataLength = ( size_t ) EMAC_GetReceiveDataSize() - ( usCRCLength - 1U );
if( xDataLength > 0U )
{
/* Obtain a network buffer to pass this data into the
stack. No storage is required as the network buffer
will point directly to the buffer that already holds
the received data. */
pxNetworkBuffer = pxNetworkBufferGet( 0, ( portTickType ) 0 );
if( pxNetworkBuffer != NULL )
{
pxNetworkBuffer->pucEthernetBuffer = EMAC_NextPacketToRead();
pxNetworkBuffer->xDataLength = xDataLength;
xRxEvent.pvData = ( void * ) pxNetworkBuffer;
/* Data was received and stored. Send a message to the IP
task to let it know. */
if( xQueueSendToBack( xNetworkEventQueue, &xRxEvent, ( portTickType ) 0 ) == pdFALSE )
{
vNetworkBufferRelease( pxNetworkBuffer );
iptraceETHERNET_RX_EVENT_LOST();
}
}
else
{
iptraceETHERNET_RX_EVENT_LOST();
}
iptraceNETWORK_INTERFACE_RECEIVE();
}
/* Release the frame. */
EMAC_UpdateRxConsumeIndex();
}
}
}
static void prvEMACDeferredInterruptHandlerTask( void *pvParameters )
{
xNetworkBufferDescriptor_t *pxNetworkBuffer;
xIPStackEvent_t xRxEvent = { eEthernetRxEvent, NULL };
( void ) pvParameters;
configASSERT( xEMACRxEventSemaphore );
for( ;; )
{
/* Wait for the EMAC interrupt to indicate that another packet has been
received. The while() loop is only needed if INCLUDE_vTaskSuspend is
set to 0 in FreeRTOSConfig.h. If INCLUDE_vTaskSuspend is set to 1
then portMAX_DELAY would be an indefinite block time and
xSemaphoreTake() would only return when the semaphore was actually
obtained. */
while( xSemaphoreTake( xEMACRxEventSemaphore, portMAX_DELAY ) == pdFALSE );
/* At least one packet has been received. */
while( EMAC_CheckReceiveIndex() != FALSE )
{
/* The buffer filled by the DMA is going to be passed into the IP
stack. Allocate another buffer for the DMA descriptor. */
pxNetworkBuffer = pxNetworkBufferGet( ipTOTAL_ETHERNET_FRAME_SIZE, ( TickType_t ) 0 );
if( pxNetworkBuffer != NULL )
{
/* Swap the buffer just allocated and referenced from the
pxNetworkBuffer with the buffer that has already been filled by
the DMA. pxNetworkBuffer will then hold a reference to the
buffer that already contains the data without any data having
been copied between buffers. */
EMAC_NextPacketToRead( pxNetworkBuffer );
#if ipconfigETHERNET_DRIVER_FILTERS_FRAME_TYPES == 1
{
if( pxNetworkBuffer->xDataLength > 0 )
{
/* If the frame would not be processed by the IP stack then
don't even bother sending it to the IP stack. */
if( eConsiderFrameForProcessing( pxNetworkBuffer->pucEthernetBuffer ) != eProcessBuffer )
{
pxNetworkBuffer->xDataLength = 0;
}
}
}
#endif
if( pxNetworkBuffer->xDataLength > 0 )
{
/* Store a pointer to the network buffer structure in the
padding space that was left in front of the Ethernet frame.
The pointer is needed to ensure the network buffer structure
can be located when it is time for it to be freed if the
Ethernet frame gets used as a zero copy buffer. */
*( ( xNetworkBufferDescriptor_t ** ) ( ( pxNetworkBuffer->pucEthernetBuffer - ipBUFFER_PADDING ) ) ) = pxNetworkBuffer;
/* Data was received and stored. Send it to the IP task
for processing. */
xRxEvent.pvData = ( void * ) pxNetworkBuffer;
if( xQueueSendToBack( xNetworkEventQueue, &xRxEvent, ( TickType_t ) 0 ) == pdFALSE )
{
/* The buffer could not be sent to the IP task so the
buffer must be released. */
vNetworkBufferRelease( pxNetworkBuffer );
iptraceETHERNET_RX_EVENT_LOST();
}
else
{
iptraceNETWORK_INTERFACE_RECEIVE();
}
}
else
{
/* The buffer does not contain any data so there is no
point sending it to the IP task. Just release it. */
vNetworkBufferRelease( pxNetworkBuffer );
iptraceETHERNET_RX_EVENT_LOST();
}
}
else
{
iptraceETHERNET_RX_EVENT_LOST();
}
/* Release the descriptor. */
EMAC_UpdateRxConsumeIndex();
}
}
}