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>

/**
 *
 * @brief Process request command for a pipe get operation
 *
 * @return N/A
 */

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

	kpipe_t pipeId = RequestOrig->args.pipe_req.req_info.pipe.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.task = _k_current_task;
	_k_state_bit_set(_k_current_task, TF_RECV);

	mycopypacket(&Request, RequestOrig);

	/* 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.pipe_xfer_req.req_info.pipe.ptr =
		(struct _k_pipe_struct *)pipeId;

	switch (_k_pipe_request_type_get(&RequestProc->args)) {
	case _SYNCREQ:
		RequestProc->args.pipe_xfer_req.data_ptr =
			Request->args.pipe_req.req_type.sync.data_ptr;
		RequestProc->args.pipe_xfer_req.total_size =
			Request->args.pipe_req.req_type.sync.total_size;
		break;
	default:
		break;
	}

	RequestProc->args.pipe_xfer_req.status = XFER_IDLE;
	RequestProc->args.pipe_xfer_req.num_pending_xfers = 0;
	RequestProc->args.pipe_xfer_req.xferred_size = 0;

	RequestProc->next = NULL;
	RequestProc->head = NULL;

	switch (RequestProc->Time.ticks) {
	case TICKS_NONE:
		_k_pipe_time_type_set(&RequestProc->args, _TIME_NB);
		break;
	case TICKS_UNLIMITED:
		_k_pipe_time_type_set(&RequestProc->args, _TIME_B);
		break;
	default:
		_k_pipe_time_type_set(&RequestProc->args, _TIME_BT);
		break;
	}

	/* start processing */

	struct _k_pipe_struct *pipe_ptr;

	pipe_ptr = RequestProc->args.pipe_xfer_req.req_info.pipe.ptr;

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

		iData2ReadFromWriters = CalcAvailWriterData(pipe_ptr->writers);
		iAvailBufferData =
			pipe_ptr->desc.available_data_count + pipe_ptr->desc.available_data_post_wrap_around;
		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(pipe_ptr, NULL /* writer */, RequestProc /* reader */);
		RequestProc->Time.ticks = ticks;

		/* check if request was processed */
		if (TERM_XXX & RequestProc->args.pipe_xfer_req.status) {
			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 != _k_pipe_time_type_get(&RequestProc->args)) {
		/* call is blocking */
		INSERT_ELM(pipe_ptr->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 = _K_SVC_PIPE_GET_TIMEOUT;
		if (_TIME_B == _k_pipe_time_type_get(&RequestProc->args)) {
			/*
			 * The writer specified TICKS_UNLIMITED, so NULL the timer.
			 */
			RequestProc->Time.timer = NULL;
			return;
		} else {
			/* { TIME_BT } */
#ifdef CANCEL_TIMERS
			if (RequestProc->args.pipe_xfer_req.xferred_size != 0) {
				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 == RequestProc->args.pipe_xfer_req.status) {
			INSERT_ELM(pipe_ptr->readers, RequestProc);
		} else {
			__ASSERT_NO_MSG(XFER_IDLE ==
				RequestProc->args.pipe_xfer_req.status);
			__ASSERT_NO_MSG(0 == RequestProc->args.pipe_xfer_req.xferred_size);
			RequestProc->Comm = _K_SVC_PIPE_GET_REPLY;
			_k_pipe_get_reply(RequestProc);
		}
		return;
	}
}

/**
 *
 * @brief Process timeout command for a pipe get operation
 *
 * @return N/A
 */

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

	myfreetimer(&(ReqProc->Time.timer));
	_k_pipe_request_status_set(&ReqProc->args.pipe_xfer_req, TERM_TMO);

	DeListWaiter(ReqProc);
	if (0 == ReqProc->args.pipe_xfer_req.num_pending_xfers) {
		_k_pipe_get_reply(ReqProc);
	}
}

/**
 *
 * @brief Process reply command for a pipe get operation
 *
 * @return N/A
 */

void _k_pipe_get_reply(struct k_args *ReqProc)
{
	__ASSERT_NO_MSG(
		(0 == ReqProc->args.pipe_xfer_req.num_pending_xfers) /*  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;
	PIPE_REQUEST_STATUS status;
	ReqOrig->Comm = _K_SVC_PIPE_GET_ACK;

	/* determine return value */

	status = ReqProc->args.pipe_xfer_req.status;
	if (TERM_TMO == status) {
		ReqOrig->Time.rcode = RC_TIME;
	} else if ((TERM_XXX | XFER_IDLE) & status) {
		K_PIPE_OPTION Option = _k_pipe_option_get(&ReqProc->args);

		if (likely(ReqProc->args.pipe_xfer_req.xferred_size ==
				   ReqProc->args.pipe_xfer_req.total_size)) {
			/* All data has been transferred */
			ReqOrig->Time.rcode = RC_OK;
		} else if (ReqProc->args.pipe_xfer_req.xferred_size != 0) {
			/* 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.pipe_ack.xferred_size =
		ReqProc->args.pipe_xfer_req.xferred_size;
	SENDARGS(ReqOrig);

	FREEARGS(ReqProc);
}

/**
 *
 * @brief Process acknowledgment command for a pipe get operation
 *
 * @return 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.pipe_ack = Request->args.pipe_ack;

	/* Reschedule the sender task */

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

	FREEARGS(Request);
}