/*****************************************************************************
Function:
bool AllocateDataTxBuffer(uint16_t bytesNeeded)
Summary:
Allocates a Data Tx buffer for use by the TCP/IP stack.
Description:
Determines if WiFi chip has enough memory to allocate a tx data buffer, and,
if so, allocates it.
Precondition:
None
Parameters:
bytesNeeded -- number of bytes needed for the data tx message
Returns:
True if data tx buffer successfully allocated, else False
Remarks:
None
*****************************************************************************/
bool AllocateDataTxBuffer(uint16_t bytesNeeded)
{
uint16_t bufAvail;
uint16_t byteCount;
/* get total bytes available for DATA tx memory pool */
bufAvail = Read16BitWFRegister(WF_HOST_WFIFO_BCNT0_REG) & 0x0fff; /* LS 12 bits contain length */
/* if enough bytes available to allocate */
if ( bufAvail >= bytesNeeded )
{
/* allocate and create the new Tx buffer (mgmt or data) */
byteCount = RawMove(RAW_DATA_TX_ID, RAW_DATA_POOL, true, bytesNeeded);
if (byteCount == 0)
{
EventEnqueue(WF_EVENT_ERROR, UD_TX_ALLOCATION_FAILED);
return false;
}
/* flag this raw window as mounted (in use) */
SetRawDataWindowState(RAW_DATA_TX_ID, WF_RAW_DATA_MOUNTED);
return true;
}
/* else not enough bytes available at this time to satisfy request */
else
{
return false;
}
}
/*****************************************************************************
Function:
void DeallocateDataRxBuffer(void)
Summary:
Deallocates a Data Rx buffer
Description:
Typically called by MACGetHeader(), the assumption being that when the stack
is checking for a newly received data message it is finished with the previously
received data message. Also called by MACGetHeader() if the SNAP header is invalid
and the packet is thrown away.
Precondition:
None
Parameters:
None
Returns:
None
Remarks:
None
*****************************************************************************/
void DeallocateDataRxBuffer(void)
{
// TODO: verify data rx is mounted
SetRawDataWindowState(RAW_DATA_RX_ID, WF_RAW_UNMOUNTED);
/* perform deallocation of raw rx buffer */
RawMove(RAW_DATA_RX_ID, RAW_DATA_POOL, false, 0);
}
/*
* Initialize RAW (Random Access Window) on MRF24WG
*/
void RawInit()
{
// Used in interrupt routine and functions in this module. The reason for
// this mechanism is because when waiting for a Raw Move complete interrupt
// we need to save the state if any other interrupts occur at the same time so
// we don't lose them
RawMoveState.rawInterruptMask = 0; // interrupt will write to this
RawMoveState.waitingForRawMoveCompleteInterrupt = false; // not waiting for RAW move complete
// By default the MRF24WG firmware mounts Scratch to RAW 1 after reset. This
// is not being used, so unmount the scratch from this RAW window.
ScratchUnmount(RAW_ID_1);
/* Permanently mount scratch memory, index defaults to 0. */
/* If one needs to know, this function returns the number of bytes in scratch memory */
ScratchMount(RAW_SCRATCH_ID);
SetRawDataWindowState(RAW_DATA_TX_ID, WF_RAW_UNMOUNTED);
SetRawDataWindowState(RAW_DATA_RX_ID, WF_RAW_UNMOUNTED);
}
/*
* Mounts most recent Rx message.
* Returns length, a number of bytes in the received message.
*
* This function mounts the most recent Rx message from the WiFi chip, which
* could be either a management or a data message.
*
* Parameters:
* rawId -- RAW ID specifying which raw window to mount the rx packet in.
*/
uint16_t RawMountRxBuffer(uint8_t rawId)
{
uint16_t length;
length = RawMove(rawId, RAW_MAC, true, 0);
// the length should never be 0 if notified of an Rx msg
if (length == 0) {
EventEnqueue(WF_EVENT_ERROR, UD_ERROR_RAW_RX_MOUNT_FAILED);
}
/* if mounting a Raw Rx data frame */
if (rawId == RAW_DATA_RX_ID) {
/* notify WiFi driver that an Rx data frame is mounted */
SetRawDataWindowState(RAW_DATA_RX_ID, WF_RAW_DATA_MOUNTED);
}
return length;
}