////////////////////////////////////////////////////////////////////////////////
|
////////////////////////////////////////////////////////////////////////////////
|
//
|
//
|
// Filename: syspipe.c
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// Filename: syspipe.c
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//
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//
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// Project: CMod S6 System on a Chip, ZipCPU demonstration project
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// Project: CMod S6 System on a Chip, ZipCPU demonstration project
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//
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//
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// Purpose: This "device" handles the primary device level interaction of
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// Purpose: This "device" handles the primary device level interaction of
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// almost all devices on the ZipOS: the pipe. A pipe, as defined
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// almost all devices on the ZipOS: the pipe. A pipe, as defined
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// here, is an O/S supported FIFO. Information written to the FIFO will
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// here, is an O/S supported FIFO. Information written to the FIFO will
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// be read from the FIFO in the order it was received. Attempts to read
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// be read from the FIFO in the order it was received. Attempts to read
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// from an empty FIFO, or equivalently to write to a full FIFO, will block
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// from an empty FIFO, or equivalently to write to a full FIFO, will block
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// the reading (writing) process until memory is available.
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// the reading (writing) process until memory is available.
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//
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//
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// Creator: Dan Gisselquist, Ph.D.
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// Creator: Dan Gisselquist, Ph.D.
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// Gisselquist Technology, LLC
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// Gisselquist Technology, LLC
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//
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//
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////////////////////////////////////////////////////////////////////////////////
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////////////////////////////////////////////////////////////////////////////////
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//
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//
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// Copyright (C) 2015-2016, Gisselquist Technology, LLC
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// Copyright (C) 2015-2016, Gisselquist Technology, LLC
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//
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//
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// This program is free software (firmware): you can redistribute it and/or
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// This program is free software (firmware): you can redistribute it and/or
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// modify it under the terms of the GNU General Public License as published
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// modify it under the terms of the GNU General Public License as published
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// by the Free Software Foundation, either version 3 of the License, or (at
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// by the Free Software Foundation, either version 3 of the License, or (at
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// your option) any later version.
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// your option) any later version.
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//
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//
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// This program is distributed in the hope that it will be useful, but WITHOUT
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// This program is distributed in the hope that it will be useful, but WITHOUT
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// ANY WARRANTY; without even the implied warranty of MERCHANTIBILITY or
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// ANY WARRANTY; without even the implied warranty of MERCHANTIBILITY or
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// FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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// FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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// for more details.
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// for more details.
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//
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//
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// You should have received a copy of the GNU General Public License along
|
// You should have received a copy of the GNU General Public License along
|
// with this program. (It's in the $(ROOT)/doc directory, run make with no
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// with this program. (It's in the $(ROOT)/doc directory, run make with no
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// target there if the PDF file isn't present.) If not, see
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// target there if the PDF file isn't present.) If not, see
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// <http://www.gnu.org/licenses/> for a copy.
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// <http://www.gnu.org/licenses/> for a copy.
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//
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//
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// License: GPL, v3, as defined and found on www.gnu.org,
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// License: GPL, v3, as defined and found on www.gnu.org,
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// http://www.gnu.org/licenses/gpl.html
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// http://www.gnu.org/licenses/gpl.html
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//
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//
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//
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//
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////////////////////////////////////////////////////////////////////////////////
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////////////////////////////////////////////////////////////////////////////////
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//
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//
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//
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//
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#include "errno.h"
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#include "errno.h"
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#include "board.h"
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#include "board.h"
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#include "taskp.h"
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#include "taskp.h"
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#include "syspipe.h"
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#include "syspipe.h"
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#include "zipsys.h"
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#include "zipsys.h"
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#include "ktraps.h"
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#include "ktraps.h"
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#include "string.h"
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|
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#ifndef NULL
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#ifndef NULL
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#define NULL (void *)0
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#define NULL (void *)0
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#endif
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#endif
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void kpush_syspipe(SYSPIPE *pipe, int val) {
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void kpush_syspipe(SYSPIPE *pipe, char val) {
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int tst = (pipe->m_head+1)&pipe->m_mask;
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int tst = (pipe->m_head+1)&pipe->m_mask;
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if (tst != pipe->m_tail) {
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if (tst != pipe->m_tail) {
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pipe->m_buf[pipe->m_head] = val;
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pipe->m_buf[pipe->m_head] = val;
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pipe->m_head = tst; // Increment the head pointer
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pipe->m_head = tst; // Increment the head pointer
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if ((pipe->m_rdtask)&&(pipe->m_rdtask != INTERRUPT_READ_TASK))
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if ((pipe->m_rdtask)&&(pipe->m_rdtask != INTERRUPT_READ_TASK))
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pipe->m_rdtask->state = SCHED_READY;
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pipe->m_rdtask->state = SCHED_READY;
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} else pipe->m_error = 1;
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} else pipe->m_error = 1;
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}
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}
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|
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extern void pipe_panic(SYSPIPE *p);
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extern void pipe_panic(SYSPIPE *p);
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int kpop_syspipe(SYSPIPE *pipe, int *vl) {
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/*
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* kpop_syspipe
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*
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* Called from an interrupt context to pop one byte off of the syspipe.
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*/
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int kpop_syspipe(SYSPIPE *pipe, char *vl) {
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if (pipe->m_head != pipe->m_tail) {
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if (pipe->m_head != pipe->m_tail) {
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// The head will *only* equal the tail if the pipe is empty.
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// We come in here, therefore, if the pipe is non-empty
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*vl = pipe->m_buf[pipe->m_tail];
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*vl = pipe->m_buf[pipe->m_tail];
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pipe->m_tail = (pipe->m_tail+1)&pipe->m_mask;
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pipe->m_tail = (pipe->m_tail+1)&pipe->m_mask;
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if (pipe->m_wrtask)
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if (pipe->m_wrtask)
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pipe->m_wrtask->state = SCHED_READY;
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pipe->m_wrtask->state = SCHED_READY;
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return 0;
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return 0;
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}
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}
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return 1; // Error condition
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return 1; // Error condition
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}
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}
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|
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/* Returns how many values are in the pipe
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/*
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* kpop_short_syspipe
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*
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* This is identical to kpop_syspipe, save that we are pulling a short value
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* off of the syspipe (i.e. a pair of chars), not just a single char.
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*/
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*/
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/* Of course ... if it's not used, why include it?
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int kpop_short_syspipe(SYSPIPE *pipe, unsigned short *vl) {
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if (pipe->m_head == pipe->m_tail)
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return 1; // Error condition
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|
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unsigned short *sptr = (unsigned short *)&pipe->m_buf[pipe->m_tail];
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// sv = pipe->m_buf[pipe->m_tail];
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*vl = *sptr;;
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pipe->m_tail = (pipe->m_tail+2)&pipe->m_mask;
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if (pipe->m_wrtask)
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pipe->m_wrtask->state = SCHED_READY;
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return 0;
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}
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/*
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int len_syspipe(SYSPIPE *p) {
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int len_syspipe(SYSPIPE *p) {
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return (p->m_head-p->m_tail) & p->m_mask;
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return (p->m_head-p->m_tail) & p->m_mask;
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} */
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} */
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|
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/* Returns how many empty spaces are in the pipe
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/* Returns how many empty spaces are in the pipe
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*/
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*/
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int num_avail_syspipe(SYSPIPE *p) {
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int num_avail_syspipe(SYSPIPE *p) {
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// if (head+1 == tail) PIPE is full
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// if (head+1 == tail) PIPE is full
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// (mask+tail-tail+1)=mask+1 &mask = 0
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// (mask+tail-tail+1)=mask+1 &mask = 0
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// if (head == tail) PIPE is empty
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// if (head == tail) PIPE is empty
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// (mask+tail-tail)=mask & mask = mask
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// (mask+tail-tail)=mask & mask = mask
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// if (head == tail+2) PIPE has two within it
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// if (head == tail+2) PIPE has two within it
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// (mask+tail-tail-2)=mask-2 & mask = mask-2
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// (mask+tail-tail-2)=mask-2 & mask = mask-2
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//
|
//
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return (p->m_tail-p->m_head-1) & p->m_mask;
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return (p->m_tail-p->m_head-1) & p->m_mask;
|
}
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}
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|
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// This will be called from a user context.
|
// This will be called from a user context.
|
// Another task may write to the pipe during this call. If the pipe becomes
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// Another task may write to the pipe during this call. If the pipe becomes
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// full, that task will block.
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// full, that task will block.
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//
|
//
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static int uread_syspipe(TASKP tsk __attribute__((__unused__)), SYSPIPE *p, int *dst, int len) {
|
static int uread_syspipe(TASKP tsk __attribute__((__unused__)),
|
|
SYSPIPE *p, char *dst, int len) {
|
int nleft= len, h;
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int nleft= len, h;
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if (len == 0) {
|
if (len == 0) {
|
// We'll only get here if we were released from within a
|
// We'll only get here if we were released from within a
|
// writing task.
|
// writing task.
|
return p->m_nread;
|
return p->m_nread;
|
} else do {
|
} else do {
|
// We have a valid read request, for a new process. Continue
|
// We have a valid read request, for a new process. Continue
|
// 'reading' until we have fulfilled the request.
|
// 'reading' until we have fulfilled the request.
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//
|
//
|
// We can read from head, just not write to it
|
// We can read from head, just not write to it
|
// As for the tail pointer -- we own it, no one else can touch
|
// As for the tail pointer -- we own it, no one else can touch
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// it.
|
// it.
|
h = ((volatile SYSPIPE *)p)->m_head;
|
h = ((volatile SYSPIPE *)p)->m_head;
|
if (h < p->m_tail) {
|
if (h < p->m_tail) {
|
// The buffer wraps around the end. Thus, we first
|
// The buffer wraps around the end. Thus, we first
|
// read anything between the tail pointer and the end
|
// read anything between the tail pointer and the end
|
int ln1 = p->m_mask+1 - p->m_tail; // Navail to be read
|
int ln1 = p->m_mask+1 - p->m_tail; // Navail to be read
|
ln1 = (ln1 > nleft) ? nleft : ln1;
|
ln1 = (ln1 > nleft) ? nleft : ln1;
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if (ln1 > 0) {
|
if (ln1 > 0) {
|
register int *src = &p->m_buf[p->m_tail];
|
memcpy(dst, &p->m_buf[p->m_tail], ln1);
|
for(int i=0; i<ln1; i++)
|
dst += ln1;
|
*dst++ = *src++;
|
|
|
|
p->m_nread += ln1;
|
p->m_nread += ln1;
|
nleft -= ln1;
|
nleft -= ln1;
|
|
|
int nt = p->m_tail+ln1;
|
int nt = p->m_tail+ln1;
|
if ((unsigned)nt > p->m_mask)
|
if ((unsigned)nt > p->m_mask)
|
nt = 0;
|
nt = 0;
|
p->m_tail = nt;
|
p->m_tail = nt;
|
}
|
}
|
|
|
// nleft is either zero, or tail
|
// nleft is either zero, or tail
|
if (nleft & -2)
|
if (nleft & -2)
|
exit(nleft);
|
exit(nleft);
|
else if (p->m_nread & -2)
|
else if (p->m_nread & -2)
|
exit(p->m_nread);
|
exit(p->m_nread);
|
}
|
}
|
|
|
// Then repeat with the second half of the buffer, from the
|
// Then repeat with the second half of the buffer, from the
|
// beginning to the head--unless we've exhausted our buffer.
|
// beginning to the head--unless we've exhausted our buffer.
|
if (nleft > 0) {
|
if (nleft > 0) {
|
// Still need to do more, wrap around our buffer and
|
// Still need to do more, wrap around our buffer and
|
// restart
|
// restart
|
int ln1 = h - p->m_tail;
|
int ln1 = h - p->m_tail;
|
ln1 = (ln1 < nleft) ? ln1 : nleft;
|
ln1 = (ln1 < nleft) ? ln1 : nleft;
|
|
|
int *src = &p->m_buf[p->m_tail];
|
memcpy(dst, &p->m_buf[p->m_tail], ln1);
|
for(int i=0; i<ln1; i++)
|
dst += ln1;
|
*dst++ = *src++;
|
|
|
|
p->m_nread += ln1;
|
p->m_nread += ln1;
|
nleft -= ln1;
|
nleft -= ln1;
|
int nt = p->m_tail+ln1; // nt = new tail value
|
int nt = p->m_tail+ln1; // nt = new tail value
|
if ((unsigned)nt > p->m_mask)
|
if ((unsigned)nt > p->m_mask)
|
nt = 0;
|
nt = 0;
|
p->m_tail = nt;
|
p->m_tail = nt;
|
|
|
if (nleft & -2)
|
if (nleft & -2)
|
exit(nleft);
|
exit(nleft);
|
else if (p->m_nread & -2)
|
else if (p->m_nread & -2)
|
exit(p->m_nread);
|
exit(p->m_nread);
|
}
|
}
|
|
|
if (nleft == 0)
|
if (nleft == 0)
|
break;
|
break;
|
|
|
// We didn't finish our read, check for a blocked writing
|
// We didn't finish our read, check for a blocked writing
|
// process to copy directly from. Note that we don't need
|
// process to copy directly from. Note that we don't need
|
// to check the status of the write task--if it is set and
|
// to check the status of the write task--if it is set and
|
// we are active, then it is blocked and waiting for us to
|
// we are active, then it is blocked and waiting for us to
|
// complete. Note also that this is treated as a volatile
|
// complete. Note also that this is treated as a volatile
|
// pointer. It can change from one time through our loop
|
// pointer. It can change from one time through our loop
|
// to the next.
|
// to the next.
|
if (((volatile SYSPIPE *)p)->m_wrtask) {
|
if (((volatile SYSPIPE *)p)->m_wrtask) {
|
int *src, ln;
|
int ln;
|
|
char *src;
|
|
|
// If the head changed before the write task blocked,
|
// If the head changed before the write task blocked,
|
// then go around again and copy some more before
|
// then go around again and copy some more before
|
// getting started
|
// getting started
|
//
|
//
|
// This should never happen, however. If a write task
|
// This should never happen, however. If a write task
|
// gets assigned while a read task exists, it doesn't
|
// gets assigned while a read task exists, it doesn't
|
// write its values into the buffer, it just waits.
|
// write its values into the buffer, it just waits.
|
// therefore we don't need to check for this.
|
// therefore we don't need to check for this.
|
//
|
//
|
// if (p->m_head != h)
|
// if (p->m_head != h)
|
// continue;
|
// continue;
|
|
|
ln = nleft;
|
ln = nleft;
|
if (p->m_wrtask->context[4] < nleft)
|
if (p->m_wrtask->context[4] < nleft)
|
ln = p->m_wrtask->context[4];
|
ln = p->m_wrtask->context[4];
|
src = (int *)p->m_wrtask->context[3];
|
src = (char *)p->m_wrtask->context[3];
|
|
memcpy(dst, src, ln);
|
for(int i=0; i<ln; i++)
|
dst += ln;
|
*dst++ = *src++;
|
src += ln;
|
|
|
p->m_nwritten += ln;
|
p->m_nwritten += ln;
|
p->m_nread += ln;
|
p->m_nread += ln;
|
|
|
nleft -= ln;
|
nleft -= ln;
|
p->m_wrtask->context[4] -= ln;
|
p->m_wrtask->context[4] -= ln;
|
p->m_wrtask->context[3] = (int)src;
|
p->m_wrtask->context[3] = (int)src;
|
|
|
// We have exhausted the write task. Release it
|
// We have exhausted the write task. Release it
|
if (p->m_wrtask->context[4] == 0) { // wr_len == 0
|
if (p->m_wrtask->context[4] == 0) { // wr_len == 0
|
// Release the write task, it has exhausted
|
// Release the write task, it has exhausted
|
// its buffer
|
// its buffer
|
TASKP w = p->m_wrtask;
|
TASKP w = p->m_wrtask;
|
// Now we allow other tasks to write into our
|
// Now we allow other tasks to write into our
|
// pipe
|
// pipe
|
p->m_wrtask = 0;
|
p->m_wrtask = 0;
|
// And here we actually release the writing
|
// And here we actually release the writing
|
// task
|
// task
|
w->state = SCHED_READY;
|
w->state = SCHED_READY;
|
}
|
}
|
}
|
}
|
|
|
// Realistically, we need to block here 'till more data is
|
// Realistically, we need to block here 'till more data is
|
// available. Need to determine how to do that. Until then,
|
// available. Need to determine how to do that. Until then,
|
// we'll just tell the scheduler to yield. This will in
|
// we'll just tell the scheduler to yield. This will in
|
// effect create a busy wait--not what we want, but it'll work.
|
// effect create a busy wait--not what we want, but it'll work.
|
if (nleft > 0) {
|
if (nleft > 0) {
|
DISABLE_INTS();
|
DISABLE_INTS();
|
h = ((volatile SYSPIPE *)p)->m_head;
|
h = ((volatile SYSPIPE *)p)->m_head;
|
if (h == p->m_tail)
|
if (h == p->m_tail)
|
wait(0,-1);
|
wait(0,-1);
|
else
|
else
|
ENABLE_INTS();
|
ENABLE_INTS();
|
}
|
}
|
} while(nleft > 0);
|
} while(nleft > 0);
|
|
|
len = p->m_nread;
|
len = p->m_nread;
|
p->m_nread = 0;
|
p->m_nread = 0;
|
// Release our ownership of the read end of the pipe
|
// Release our ownership of the read end of the pipe
|
DISABLE_INTS();
|
DISABLE_INTS();
|
p->m_rdtask = NULL;
|
p->m_rdtask = NULL;
|
if (((volatile SYSPIPE *)p)->m_wrtask)
|
if (((volatile SYSPIPE *)p)->m_wrtask)
|
p->m_wrtask->state = SCHED_READY;
|
p->m_wrtask->state = SCHED_READY;
|
ENABLE_INTS();
|
ENABLE_INTS();
|
|
|
// We have accomplished our read
|
// We have accomplished our read
|
//
|
//
|
return len;
|
return len;
|
}
|
}
|
|
|
static int uwrite_syspipe(TASKP tsk __attribute__((__unused__)),
|
static int uwrite_syspipe(TASKP tsk __attribute__((__unused__)),
|
SYSPIPE *p, int *src, int len) {
|
SYSPIPE *p, char *src, int len) {
|
int nleft = len;
|
int nleft = len;
|
|
|
// The kernel guarantees, before we come into here, that we have a
|
// The kernel guarantees, before we come into here, that we have a
|
// valid write request.
|
// valid write request.
|
do {
|
do {
|
// We try to fill this request without going through the pipes
|
// We try to fill this request without going through the pipes
|
// memory at all. Hence, if there is a read task that is
|
// memory at all. Hence, if there is a read task that is
|
// waiting/suspended, waiting on a write (this must've happened
|
// waiting/suspended, waiting on a write (this must've happened
|
// since we started)--write directly into the read buffer first.
|
// since we started)--write directly into the read buffer first.
|
|
|
// If there is a read task blocked, the pipe must be empty
|
// If there is a read task blocked, the pipe must be empty
|
TASKP rdtask = ((volatile SYSPIPE *)p)->m_rdtask;
|
TASKP rdtask = ((volatile SYSPIPE *)p)->m_rdtask;
|
if (rdtask == INTERRUPT_READ_TASK) {
|
if (rdtask == INTERRUPT_READ_TASK) {
|
// We need to copy everything to the buffer
|
// We need to copy everything to the buffer
|
} else if (rdtask) {
|
} else if (rdtask) {
|
int ln = nleft;
|
int ln = nleft;
|
if (ln > p->m_rdtask->context[4])
|
if (ln > p->m_rdtask->context[4])
|
ln = p->m_rdtask->context[4];
|
ln = p->m_rdtask->context[4];
|
int *dst = (int *)p->m_rdtask->context[3];
|
memcpy((char *)p->m_rdtask->context[3], src, ln);
|
for(int i=0; i<ln; i++)
|
src += ln;
|
*dst++ = *src++;
|
|
p->m_nread += ln;
|
p->m_nread += ln;
|
p->m_rdtask->context[3]+= ln;
|
p->m_rdtask->context[3]+= ln;
|
p->m_rdtask->context[4]-= ln;
|
p->m_rdtask->context[4]-= ln;
|
nleft -= ln;
|
nleft -= ln;
|
p->m_nwritten += ln;
|
p->m_nwritten += ln;
|
|
|
// Realistically, we always need to wake up the reader
|
// Realistically, we always need to wake up the reader
|
// at this point. Either 1) we exhausted the readers
|
// at this point. Either 1) we exhausted the readers
|
// buffer, or 2) we exhausted our own and the reader
|
// buffer, or 2) we exhausted our own and the reader
|
// needs to take over. Here, we only handle the first
|
// needs to take over. Here, we only handle the first
|
// case, leaving the rest for later.
|
// case, leaving the rest for later.
|
if (p->m_rdtask->context[4] == 0) {
|
if (p->m_rdtask->context[4] == 0) {
|
TASKP r = p->m_rdtask;
|
TASKP r = p->m_rdtask;
|
// Detach the reader task
|
// Detach the reader task
|
p->m_rdtask = 0;
|
p->m_rdtask = 0;
|
// Wake up the reader
|
// Wake up the reader
|
r->state = SCHED_READY;
|
r->state = SCHED_READY;
|
}
|
}
|
|
|
// While it might appear that we might close our loop
|
// While it might appear that we might close our loop
|
// here, that's not quite the case. It may be that the
|
// here, that's not quite the case. It may be that the
|
// pipe is read from an interrupt context. In that
|
// pipe is read from an interrupt context. In that
|
// case, there will never be any reader tasks, but we
|
// case, there will never be any reader tasks, but we
|
// will still need to loop.
|
// will still need to loop.
|
|
|
// Now that we've filled any existing reader task, we
|
// Now that we've filled any existing reader task, we
|
// check whether or not we fit into the buffer. The
|
// check whether or not we fit into the buffer. The
|
// rule is: don't write into the buffer unless
|
// rule is: don't write into the buffer unless
|
// everything will fit. Why? Well, if you have to
|
// everything will fit. Why? Well, if you have to
|
// block anyway, why not see if you can't avoid a
|
// block anyway, why not see if you can't avoid a
|
// double copy?
|
// double copy?
|
if (nleft == 0)
|
if (nleft == 0)
|
break;
|
break;
|
}
|
}
|
|
|
// Copy whatever we have into the pipe's buffer
|
// Copy whatever we have into the pipe's buffer
|
int navail = num_avail_syspipe(p);
|
int navail = num_avail_syspipe(p);
|
if ((nleft <= navail)
|
if ((nleft <= navail)
|
||((rdtask == INTERRUPT_READ_TASK)&&(navail>0))) {
|
||((rdtask == INTERRUPT_READ_TASK)&&(navail>0))) {
|
// Either there is no immediate reader task, or
|
// Either there is no immediate reader task, or
|
// the reader has been exhausted, but we've go
|
// the reader has been exhausted, but we've go
|
// more to write.
|
// more to write.
|
//
|
//
|
// Note that we no longer need to check what
|
// Note that we no longer need to check what
|
// will fit into the pipe. We know the entire
|
// will fit into the pipe. We know the entire
|
// rest of our buffer will fit.
|
// rest of our buffer will fit.
|
|
|
{ // Write into the first half of the pipe
|
{ // Write into the first half of the pipe
|
// Be careful not to change head until all is written
|
// Be careful not to change head until all is written
|
// so that it remains consistent under interrupt
|
// so that it remains consistent under interrupt
|
// conditions.
|
// conditions.
|
int ln = p->m_mask+1-p->m_head;
|
int ln = p->m_mask+1-p->m_head;
|
int *dst = &p->m_buf[p->m_head];
|
|
if (ln > nleft) ln = nleft;
|
if (ln > nleft) ln = nleft;
|
if (ln > navail) ln = navail;
|
if (ln > navail) ln = navail;
|
|
|
for(int i=0; i<ln; i++)
|
memcpy((void *)&p->m_buf[p->m_head], src, ln);
|
*dst++ = *src++;
|
src += ln;
|
|
|
p->m_head = (p->m_head+ln)&p->m_mask;
|
p->m_head = (p->m_head+ln)&p->m_mask;
|
nleft -= ln;
|
nleft -= ln;
|
p->m_nwritten += ln;
|
p->m_nwritten += ln;
|
navail -= ln;
|
navail -= ln;
|
}
|
}
|
|
|
/*
|
|
// Write into the rest of the pipe
|
|
if ((0 == p->m_head)&&(nleft>0)&&(navail>0)) {
|
|
int ln = navail;
|
|
if (nleft < ln)
|
|
ln = nleft;
|
|
int *dst = &p->m_buf[p->m_head];
|
|
|
|
for(int i=0; i<ln; i++)
|
|
*dst++ = *src++;
|
|
|
|
p->m_head += ln;
|
|
p->m_nwritten += ln;
|
|
nleft -= ln;
|
|
}*/
|
|
}
|
}
|
|
|
if ((nleft > 0)&&(navail == 0)) {
|
if ((nleft > 0)&&(navail == 0)) {
|
if (rdtask == INTERRUPT_READ_TASK) {
|
if (rdtask == INTERRUPT_READ_TASK) {
|
DISABLE_INTS();
|
DISABLE_INTS();
|
if (0==num_avail_syspipe(p))
|
if (0==num_avail_syspipe(p))
|
wait(0,-1);
|
wait(0,-1);
|
else ENABLE_INTS();
|
else ENABLE_INTS();
|
} else {
|
} else {
|
DISABLE_INTS();
|
DISABLE_INTS();
|
if (!((volatile SYSPIPE *)p)->m_rdtask)
|
if (!((volatile SYSPIPE *)p)->m_rdtask)
|
wait(0,-1); // Should really be a wait
|
wait(0,-1); // Should really be a wait
|
// on JIFFIES and if JIFFIES expired
|
// on JIFFIES and if JIFFIES expired
|
// (i.e. write timeout) then break;
|
// (i.e. write timeout) then break;
|
else ENABLE_INTS();
|
else ENABLE_INTS();
|
}
|
}
|
}
|
}
|
} while(nleft > 0);
|
} while(nleft > 0);
|
|
|
int nw= p->m_nwritten;
|
int nw= p->m_nwritten;
|
p->m_wrtask = 0;
|
p->m_wrtask = 0;
|
return nw;
|
return nw;
|
}
|
}
|
|
|
// This will be called from a kernel (interrupt) context
|
// This will be called from a kernel (interrupt) context
|
void kread_syspipe(TASKP tsk, int dev, int *dst, int len) {
|
void kread_syspipe(TASKP tsk, int dev, char *dst, int len) {
|
SYSPIPE *p = (SYSPIPE *)dev;
|
SYSPIPE *p = (SYSPIPE *)dev;
|
if (p->m_rdtask != NULL) {
|
if (p->m_rdtask != NULL) {
|
// If the pipe already has a read task, then we fail
|
// If the pipe already has a read task, then we fail
|
tsk->context[1] = -EBUSY;
|
tsk->context[1] = -EBUSY;
|
zip_halt();
|
zip_halt();
|
} else if (p->m_error) {
|
} else if (p->m_error) {
|
// If there's been an overrun, let the reader know on the
|
// If there's been an overrun, let the reader know on the
|
// next read--i.e. this one. Also, clear the error condition
|
// next read--i.e. this one. Also, clear the error condition
|
// so that the following read will succeed.
|
// so that the following read will succeed.
|
tsk->context[1] = -EIO;
|
tsk->context[1] = -EIO;
|
p->m_tail = p->m_head;
|
p->m_tail = p->m_head;
|
p->m_error = 0;
|
p->m_error = 0;
|
} else if (len <= 0) {
|
} else if (len <= 0) {
|
tsk->context[1] = -EFAULT;
|
tsk->context[1] = -EFAULT;
|
zip_halt();
|
zip_halt();
|
} else if (!valid_ram_region(dst, len)) {
|
} else if (!valid_ram_region(dst, len)) {
|
// Bad parameters
|
// Bad parameters
|
tsk->context[1] = -EFAULT;
|
tsk->context[1] = -EFAULT;
|
zip_halt();
|
zip_halt();
|
} else {
|
} else {
|
// Take ownership of the read end of the pipe
|
// Take ownership of the read end of the pipe
|
p->m_rdtask = tsk;
|
p->m_rdtask = tsk;
|
p->m_nread = 0;
|
p->m_nread = 0;
|
tsk->context[1] = (int)tsk;
|
tsk->context[1] = (int)tsk;
|
tsk->context[2] = (int)p;
|
tsk->context[2] = (int)p;
|
// These are already set, else we'd set them again
|
// These are already set, else we'd set them again
|
// tsk->context[3] = (int)dst;
|
// tsk->context[3] = (int)dst;
|
// tsk->context[4] = len;
|
// tsk->context[4] = len;
|
tsk->context[15] = (int)uread_syspipe;
|
tsk->context[15] = (int)uread_syspipe;
|
|
|
// If there is already a write task, make sure it is awake
|
// If there is already a write task, make sure it is awake
|
if (p->m_wrtask) {
|
if (p->m_wrtask) {
|
tsk->state = SCHED_WAITING;
|
tsk->state = SCHED_WAITING;
|
p->m_wrtask->state = SCHED_READY;
|
p->m_wrtask->state = SCHED_READY;
|
} else if (p->m_head == p->m_tail)
|
} else if (p->m_head == p->m_tail)
|
// If the pipe is empty, block the read task
|
// If the pipe is empty, block the read task
|
tsk->state = SCHED_WAITING;
|
tsk->state = SCHED_WAITING;
|
|
|
// On return, this will bring us back to user space, inside our
|
// On return, this will bring us back to user space, inside our
|
// user space version of the read system call
|
// user space version of the read system call
|
}
|
}
|
}
|
}
|
|
|
void kwrite_syspipe(TASKP tsk, int dev, int *src, int len) {
|
void kwrite_syspipe(TASKP tsk, int dev, char *src, int len) {
|
SYSPIPE *p = (SYSPIPE *)dev;
|
SYSPIPE *p = (SYSPIPE *)dev;
|
if (p->m_wrtask != NULL) {
|
if (p->m_wrtask != NULL) {
|
// If the pipe already has a write task, then we fail
|
// If the pipe already has a write task, then we fail
|
tsk->context[1] = -EBUSY;
|
tsk->context[1] = -EBUSY;
|
} else if (len <= 0) {
|
} else if (len <= 0) {
|
tsk->context[1] = -EFAULT;
|
tsk->context[1] = -EFAULT;
|
} else if (!valid_mem_region(src, len)) {
|
} else if (!valid_mem_region(src, len)) {
|
// Bad parameters
|
// Bad parameters
|
tsk->context[1] = -EFAULT;
|
tsk->context[1] = -EFAULT;
|
zip_halt();
|
zip_halt();
|
} else {
|
} else {
|
// Take ownership of the write end of the pipe
|
// Take ownership of the write end of the pipe
|
p->m_wrtask = tsk;
|
p->m_wrtask = tsk;
|
p->m_nwritten = 0;
|
p->m_nwritten = 0;
|
tsk->context[1] = (int)tsk;
|
tsk->context[1] = (int)tsk;
|
tsk->context[2] = (int)p;
|
tsk->context[2] = (int)p;
|
// These are already set, else we'd set them again
|
// These are already set, else we'd set them again
|
// tsk->context[3] = (int)src;
|
// tsk->context[3] = (int)src;
|
// tsk->context[4] = len;
|
// tsk->context[4] = len;
|
tsk->context[15] = (int)uwrite_syspipe;
|
tsk->context[15] = (int)uwrite_syspipe;
|
|
|
// If a reader task currently exists, then block until that
|
// If a reader task currently exists, then block until that
|
// task either finishes or releases us
|
// task either finishes or releases us
|
if ((p->m_rdtask)&&(p->m_rdtask != INTERRUPT_READ_TASK)) {
|
if ((p->m_rdtask)&&(p->m_rdtask != INTERRUPT_READ_TASK)) {
|
tsk->state = SCHED_WAITING;
|
tsk->state = SCHED_WAITING;
|
p->m_rdtask->state = SCHED_READY;
|
p->m_rdtask->state = SCHED_READY;
|
} else if (((p->m_head+1)&p->m_mask) == (unsigned)p->m_tail)
|
} else if (((p->m_head+1)&p->m_mask) == (unsigned)p->m_tail)
|
// If the pipe is empty, block until there's data
|
// If the pipe is empty, block until there's data
|
tsk->state = SCHED_WAITING;
|
tsk->state = SCHED_WAITING;
|
|
|
// On return, this will bring us back to user space, in our
|
// On return, this will bring us back to user space, in our
|
// user space write call
|
// user space write call
|
}
|
}
|
}
|
}
|
|
|
