1456183b0f0df8d4688f3d577e71e7525445196f
1 /**
2 * Copyright (C) ARM Limited 2010-2012. All rights reserved.
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License version 2 as
6 * published by the Free Software Foundation.
7 */
9 #include <stdlib.h>
10 #include <string.h>
11 #include <unistd.h>
12 #include "Fifo.h"
13 #include "Logging.h"
15 extern void handleException();
17 Fifo::Fifo(int numBuffers, int bufferSize) {
18 int which;
20 if (numBuffers > FIFO_BUFFER_LIMIT) {
21 logg->logError(__FILE__, __LINE__, "Number of fifo buffers exceeds maximum");
22 handleException();
23 }
24 mNumBuffers = numBuffers;
25 mBufferSize = bufferSize;
26 mWriteCurrent = 0;
27 mReadCurrent = mNumBuffers - 1; // (n-1) pipelined
29 for (which=0; which<mNumBuffers; which++) {
30 // initialized read-to-write sem to 1, so that first wait goes through; write-to-read init'd to 0
31 if (sem_init(&mReadToWriteSem[which], 0, 1) ||
32 sem_init(&mWriteToReadSem[which], 0, 0)) {
33 logg->logError(__FILE__, __LINE__, "sem_init(%d) failed", which);
34 handleException();
35 }
36 // page-align allocate buffers
37 mBuffer[which] = (char*)valloc(bufferSize);
38 if (mBuffer[which] == NULL) {
39 logg->logError(__FILE__, __LINE__, "failed to allocate %d bytes", bufferSize);
40 handleException();
41 }
42 // touch each page to fault it in
43 for (int i=0; i<bufferSize; i+= getpagesize()) {
44 *mBuffer[which] = 0;
45 }
46 }
47 }
49 Fifo::~Fifo() {
50 for (int which=0; which<mNumBuffers; which++) {
51 if (mBuffer[which] != NULL) {
52 free(mBuffer[which]);
53 mBuffer[which] = NULL;
54 }
55 }
56 }
58 int Fifo::depth(void) {
59 return mNumBuffers;
60 }
62 int Fifo::numReadToWriteBuffersFilled() {
63 int value;
64 int numFilled = 0;
65 for (int which=0; which<mNumBuffers; which++) {
66 if (sem_getvalue(&mReadToWriteSem[which], &value) == 0) numFilled += value;
67 }
68 return numFilled;
69 }
71 int Fifo::numWriteToReadBuffersFilled() {
72 int value;
73 int numFilled = 0;
74 for (int which=0; which<mNumBuffers; which++) {
75 if (sem_getvalue(&mWriteToReadSem[which], &value) == 0) numFilled += value;
76 }
77 return numFilled;
78 }
80 char* Fifo::start() {
81 sem_wait(&mReadToWriteSem[mWriteCurrent]);
82 return mBuffer[mWriteCurrent];
83 }
85 char* Fifo::write(int length) {
86 mLength[mWriteCurrent] = length;
87 sem_post(&mWriteToReadSem[mWriteCurrent]);
88 mWriteCurrent = (mWriteCurrent + 1) % mNumBuffers;
89 sem_wait(&mReadToWriteSem[mWriteCurrent]);
90 return mBuffer[mWriteCurrent];
91 }
93 char* Fifo::read(int* length) {
94 static bool firstTime = true;
95 if (!firstTime) {
96 sem_post(&mReadToWriteSem[mReadCurrent]);
97 }
98 firstTime = false;
99 mReadCurrent = (mReadCurrent + 1) % mNumBuffers;
100 sem_wait(&mWriteToReadSem[mReadCurrent]);
101 *length = mLength[mReadCurrent];
102 return mBuffer[mReadCurrent];
103 }