kernel/microkernel/k_pipe_get.c

/* command processing for pipe get operation */

/*
 * Copyright (c) 1997-2014 Wind River Systems, Inc.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * 1) Redistributions of source code must retain the above copyright notice,
 * this list of conditions and the following disclaimer.
 *
 * 2) Redistributions in binary form must reproduce the above copyright notice,
 * this list of conditions and the following disclaimer in the documentation
 * and/or other materials provided with the distribution.
 *
 * 3) Neither the name of Wind River Systems nor the names of its contributors
 * may be used to endorse or promote products derived from this software without
 * specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

#include <micro_private.h>
#include <k_pipe_util.h>
#include <toolchain.h>
#include <sections.h>
#include <misc/__assert.h>

/*******************************************************************************
*
* _k_pipe_get_request - process request command for a pipe get operation
*
* RETURNS: N/A
*/

void _k_pipe_get_request(struct k_args *RequestOrig)
{
	struct k_args *Request;
	struct k_args *RequestProc;

	kpipe_t pipeId = RequestOrig->Args.ChReq.ReqInfo.ChRef.Id;

	/* If it's a poster, then don't deschedule the task */

	/* First we save the pointer to the task's TCB for rescheduling later */
	RequestOrig->Ctxt.proc = _k_current_task;
	_k_state_bit_set(_k_current_task, TF_RECV);

	mycopypacket(&Request, RequestOrig);

	/* if we end up here, we arrived at destination node and the packet
	   Request is not local */

	/* Now, we need a new packet for processing of the request;
	   the Request package is too small b/c of space lost due to possible
	   embedded local data
	 */

	mycopypacket(&RequestProc, Request);
	RequestProc->Args.ChProc.ReqInfo.ChRef.pPipe =
		&(_k_pipe_list[OBJ_INDEX(pipeId)]);

	switch (ChxxxGetReqType(&(RequestProc->Args))) {
	case _SYNCREQ:
		RequestProc->Args.ChProc.pData =
			Request->Args.ChReq.ReqType.Sync.pData;
		RequestProc->Args.ChProc.iSizeTotal =
			Request->Args.ChReq.ReqType.Sync.iSizeTotal;
		break;
	default:
		break;
	}

	RequestProc->Args.ChProc.Status = XFER_IDLE;
	RequestProc->Args.ChProc.iNbrPendXfers = 0;
	RequestProc->Args.ChProc.iSizeXferred = 0;

	RequestProc->Forw = NULL;
	RequestProc->Head = NULL;

	switch (RequestProc->Time.ticks) {
	case TICKS_NONE:
		ChxxxSetTimeType((K_ARGS_ARGS *)&(RequestProc->Args), _TIME_NB);
		break;
	case TICKS_UNLIMITED:
		ChxxxSetTimeType((K_ARGS_ARGS *)&(RequestProc->Args), _TIME_B);
		break;
	default:
		ChxxxSetTimeType((K_ARGS_ARGS *)&(RequestProc->Args), _TIME_BT);
		break;
	}

	/* start processing */

	struct pipe_struct *pPipe;
	struct k_chproc *pChProcArgs;

	pChProcArgs = &(RequestProc->Args.ChProc);
	pPipe = pChProcArgs->ReqInfo.ChRef.pPipe;

	do {
		int iData2ReadFromWriters;
		int iAvailBufferData;
		int iTotalData2Read;
		int32_t ticks;

		iData2ReadFromWriters = CalcAvailWriterData(pPipe->Writers);
		iAvailBufferData =
			pPipe->Buff.iAvailDataCont +pPipe->Buff.iAvailDataAWA;
		iTotalData2Read =
			iAvailBufferData + iData2ReadFromWriters;

		if (0 == iTotalData2Read)
			break; /* special case b/c even not good enough for 1_TO_N */

		/* (possibly) do some processing */
		ticks = RequestProc->Time.ticks;
		RequestProc->Time.timer = NULL;
		_k_pipe_process(pPipe, NULL /* writer */, RequestProc /* reader */);
		RequestProc->Time.ticks = ticks;

		/* check if request was processed */
		if (TERM_XXX & ChReqGetStatus(&(RequestProc->Args.ChProc))) {
			RequestProc->Time.timer = NULL; /* not really required */
			return; /* not listed anymore --> completely processed */
		}

	} while (0);

	/*
	 * if we got up to here, we did none or SOME (partial)
	 * processing on the request
	 */

	if (_TIME_NB != ChxxxGetTimeType((K_ARGS_ARGS *)&(RequestProc->Args))) {
		/* call is blocking */
		INSERT_ELM(pPipe->Readers, RequestProc);
		/*
		 * NOTE: It is both faster and simpler to blindly assign the
		 * PIPE_GET_TIMEOUT microkernel command to the packet even though it
		 * is only useful to the finite timeout case.
		 */
		RequestProc->Comm = PIPE_GET_TIMEOUT;
		if (_TIME_B ==
			ChxxxGetTimeType((K_ARGS_ARGS *)&(RequestProc->Args))) {
			/*
			 * The writer specified TICKS_UNLIMITED, so NULL the timer.
			 */
			RequestProc->Time.timer = NULL;
			return;
		} else {
			/* { TIME_BT } */
#ifdef CANCEL_TIMERS
			if (ChReqSizeXferred(&(RequestProc->Args.ChProc))) {
				RequestProc->Time.timer = NULL;
			} else
#endif
				/* enlist a new timer into the timeout chain */
				_k_timeout_alloc(RequestProc);

			return;
		}
	} else {
		/* call is non-blocking;
		   Check if we don't have to queue it b/c it could not
		   be processed at once
		 */
		RequestProc->Time.timer = NULL;

		if (XFER_BUSY == ChReqGetStatus(&(RequestProc->Args.ChProc))) {
			INSERT_ELM(pPipe->Readers, RequestProc);
		} else {
			__ASSERT_NO_MSG(XFER_IDLE ==
				   ChReqGetStatus(&(RequestProc->Args.ChProc)));
			__ASSERT_NO_MSG(0 ==
				   ChReqSizeXferred(&(RequestProc->Args.ChProc)));
			RequestProc->Comm = PIPE_GET_REPLY;
			_k_pipe_get_reply(RequestProc);
		}
		return;
	}
}

/*******************************************************************************
*
* _k_pipe_get_timeout - process timeout command for a pipe get operation
*
* RETURNS: N/A
*/

void _k_pipe_get_timeout(struct k_args *ReqProc)
{
	__ASSERT_NO_MSG(NULL != ReqProc->Time.timer);

	myfreetimer(&(ReqProc->Time.timer));
	ChReqSetStatus(&(ReqProc->Args.ChProc), TERM_TMO);

	DeListWaiter(ReqProc);
	if (0 == ReqProc->Args.ChProc.iNbrPendXfers) {
		_k_pipe_get_reply(ReqProc);
	}
}

/*******************************************************************************
*
* _k_pipe_get_reply - process reply command for a pipe get operation
*
* RETURNS: N/A
*/

void _k_pipe_get_reply(struct k_args *ReqProc)
{
	__ASSERT_NO_MSG(
		(0 == ReqProc->Args.ChProc.iNbrPendXfers) /*  no pending Xfers */
	    && (NULL == ReqProc->Time.timer) /*  no pending timer */
	    && (NULL == ReqProc->Head)); /*  not in list */

	/* orig packet must be sent back, not ReqProc */

	struct k_args *ReqOrig = ReqProc->Ctxt.args;
	CHREQ_STATUS ChReqStatus;
	ReqOrig->Comm = PIPE_GET_ACK;

	/* determine return value */

	ChReqStatus = ChReqGetStatus(&(ReqProc->Args.ChProc));
	if (TERM_TMO == ChReqStatus) {
		ReqOrig->Time.rcode = RC_TIME;
	} else if ((TERM_XXX | XFER_IDLE) & ChReqStatus) {
		K_PIPE_OPTION Option = ChxxxGetChOpt(&(ReqProc->Args));

		if (likely(0 == ChReqSizeLeft(&(ReqProc->Args.ChProc)))) {
			/* All data has been transferred */
			ReqOrig->Time.rcode = RC_OK;
		} else if (ChReqSizeXferred(&(ReqProc->Args.ChProc))) {
			/* Some but not all data has been transferred */
			ReqOrig->Time.rcode = (Option == _ALL_N) ?
								  RC_INCOMPLETE : RC_OK;
		} else {
			/* No data has been transferred */
			ReqOrig->Time.rcode = (Option == _0_TO_N) ? RC_OK : RC_FAIL;
		}
	} else {
		/* unknown (invalid) status */
		__ASSERT_NO_MSG(1 == 0); /* should not come here */
	}

	ReqOrig->Args.ChAck.iSizeXferred = ReqProc->Args.ChProc.iSizeXferred;
	SENDARGS(ReqOrig);

	FREEARGS(ReqProc);
}

/*******************************************************************************
*
* _k_pipe_get_ack - process acknowledgment command for a pipe get operation
*
* RETURNS: N/A
*/

void _k_pipe_get_ack(struct k_args *Request)
{
	struct k_args *LocalReq;

	LocalReq = Request->Ctxt.args;
	LocalReq->Time.rcode = Request->Time.rcode;
	LocalReq->Args.ChAck = Request->Args.ChAck;

	/* Reschedule the sender task */

	_k_state_bit_reset(LocalReq->Ctxt.proc, TF_RECV | TF_RECVDATA);

	FREEARGS(Request);
}