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1 // Copyright (c) 1998-2009 Nokia Corporation and/or its subsidiary(-ies). |
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2 // All rights reserved. |
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3 // This component and the accompanying materials are made available |
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4 // under the terms of the License "Eclipse Public License v1.0" |
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5 // which accompanies this distribution, and is available |
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6 // at the URL "http://www.eclipse.org/legal/epl-v10.html". |
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7 // |
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8 // Initial Contributors: |
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9 // Nokia Corporation - initial contribution. |
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10 // |
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11 // Contributors: |
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12 // |
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13 // Description: |
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14 // e32\nkern\nk_timer.cpp |
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15 // Fast Millisecond Timer Implementation |
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16 // This file is just a template - you'd be mad not to machine code this |
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17 // |
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18 // |
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19 |
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20 #include "nk_priv.h" |
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21 |
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22 const TInt KTimerQDfcPriority=6; |
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23 |
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24 GLDEF_D NTimerQ TheTimerQ; |
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25 |
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26 #ifndef __MSTIM_MACHINE_CODED__ |
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27 #ifdef _DEBUG |
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28 #define __DEBUG_CALLBACK(n) {if (iDebugFn) (*iDebugFn)(iDebugPtr,n);} |
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29 #else |
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30 #define __DEBUG_CALLBACK(n) |
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31 #endif |
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32 |
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33 |
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34 /** Starts a nanokernel timer in one-shot mode with ISR callback. |
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35 |
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36 Queues the timer to expire in the specified number of nanokernel ticks. The |
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37 actual wait time will be at least that much and may be up to one tick more. |
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38 The expiry handler will be called in ISR context. |
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39 |
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40 Note that NKern::TimerTicks() can be used to convert milliseconds to ticks. |
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41 |
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42 @param aTime Timeout in nanokernel ticks |
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43 |
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44 @return KErrNone if no error; KErrInUse if timer is already active. |
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45 |
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46 @pre Any context |
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47 |
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48 @see NKern::TimerTicks() |
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49 */ |
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50 EXPORT_C TInt NTimer::OneShot(TInt aTime) |
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51 { |
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52 return OneShot(aTime,FALSE); |
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53 } |
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54 |
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55 |
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56 /** Starts a nanokernel timer in one-shot mode with ISR or DFC callback. |
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57 |
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58 Queues the timer to expire in the specified number of nanokernel ticks. The |
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59 actual wait time will be at least that much and may be up to one tick more. |
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60 The expiry handler will be called in either ISR context or in the context |
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61 of the nanokernel timer thread (DfcThread1). |
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62 |
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63 Note that NKern::TimerTicks() can be used to convert milliseconds to ticks. |
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64 |
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65 @param aTime Timeout in nanokernel ticks |
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66 @param aDfc TRUE if DFC callback required, FALSE if ISR callback required. |
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67 |
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68 @return KErrNone if no error; KErrInUse if timer is already active. |
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69 |
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70 @pre Any context |
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71 |
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72 @see NKern::TimerTicks() |
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73 */ |
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74 EXPORT_C TInt NTimer::OneShot(TInt aTime, TBool aDfc) |
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75 { |
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76 __NK_ASSERT_DEBUG(aTime>=0); |
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77 |
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78 /** iFunction could be set to NULL after NTimer::OneShot(TInt, TDfc&) call. |
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79 Call-back mechanism cannot be changed in the life time of a timer. */ |
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80 __NK_ASSERT_DEBUG(iFunction!=NULL); |
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81 |
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82 TInt irq=NKern::DisableAllInterrupts(); |
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83 if (iState!=EIdle) |
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84 { |
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85 NKern::RestoreInterrupts(irq); |
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86 return KErrInUse; |
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87 } |
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88 iCompleteInDfc=TUint8(aDfc?1:0); |
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89 iTriggerTime=TheTimerQ.iMsCount+(TUint32)aTime; |
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90 TheTimerQ.Add(this); |
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91 NKern::RestoreInterrupts(irq); |
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92 return KErrNone; |
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93 } |
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94 |
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95 /** Starts a nanokernel timer in one-shot mode with callback in dfc thread that provided DFC belongs to. |
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96 |
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97 Queues the timer to expire in the specified number of nanokernel ticks. The |
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98 actual wait time will be at least that much and may be up to one tick more. |
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99 On expiry aDfc will be queued in ISR context. |
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100 |
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101 Note that NKern::TimerTicks() can be used to convert milliseconds to ticks. |
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102 |
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103 @param aTime Timeout in nanokernel ticks |
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104 @param aDfc - Dfc to be queued when the timer expires. |
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105 |
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106 @return KErrNone if no error; KErrInUse if timer is already active. |
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107 |
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108 @pre Any context |
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109 |
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110 @see NKern::TimerTicks() |
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111 */ |
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112 EXPORT_C TInt NTimer::OneShot(TInt aTime, TDfc& aDfc) |
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113 { |
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114 __NK_ASSERT_DEBUG(aTime>=0); |
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115 TInt irq=NKern::DisableAllInterrupts(); |
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116 if (iState!=EIdle) |
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117 { |
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118 NKern::RestoreInterrupts(irq); |
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119 return KErrInUse; |
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120 } |
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121 iCompleteInDfc = 0; |
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122 iFunction = NULL; |
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123 iPtr = (TAny*) &aDfc; |
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124 iTriggerTime=TheTimerQ.iMsCount+(TUint32)aTime; |
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125 TheTimerQ.Add(this); |
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126 NKern::RestoreInterrupts(irq); |
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127 return KErrNone; |
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128 } |
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129 |
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130 |
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131 /** Starts a nanokernel timer in zero-drift periodic mode with ISR or DFC callback. |
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132 |
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133 Queues the timer to expire in the specified number of nanokernel ticks, |
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134 measured from the time at which it last expired. This allows exact periodic |
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135 timers to be implemented with no drift caused by delays in requeueing the |
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136 timer. |
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137 |
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138 The expiry handler will be called in the same context as the previous timer |
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139 expiry. Generally the way this is used is that NTimer::OneShot() is used to start |
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140 the first time interval and this specifies whether the callback is in ISR context |
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141 or in the context of the nanokernel timer thread (DfcThread1) or other Dfc thread. |
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142 The expiry handler then uses NTimer::Again() to requeue the timer. |
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143 |
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144 @param aTime Timeout in nanokernel ticks |
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145 |
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146 @return KErrNone if no error; KErrInUse if timer is already active; |
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147 KErrArgument if the requested expiry time is in the past. |
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148 |
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149 @pre Any context |
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150 */ |
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151 EXPORT_C TInt NTimer::Again(TInt aTime) |
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152 // |
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153 // Wait aTime from last trigger time - used for periodic timers |
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154 // |
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155 { |
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156 __NK_ASSERT_DEBUG(aTime>0); |
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157 TInt irq=NKern::DisableAllInterrupts(); |
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158 if (iState!=EIdle) |
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159 { |
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160 NKern::RestoreInterrupts(irq); |
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161 return KErrInUse; |
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162 } |
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163 TUint32 nextTick=TheTimerQ.iMsCount; |
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164 TUint32 trigger=iTriggerTime+(TUint32)aTime; |
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165 TUint32 d=trigger-nextTick; |
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166 if (d>=0x80000000) |
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167 { |
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168 NKern::RestoreInterrupts(irq); |
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169 return KErrArgument; // requested time is in the past |
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170 } |
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171 iTriggerTime=trigger; |
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172 TheTimerQ.Add(this); |
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173 NKern::RestoreInterrupts(irq); |
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174 return KErrNone; |
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175 } |
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176 |
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177 |
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178 /** Cancels a nanokernel timer. |
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179 |
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180 Removes this timer from the nanokernel timer queue. Does nothing if the |
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181 timer is inactive or has already expired. |
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182 Note that if the timer was queued and DFC callback requested it is possible |
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183 for the expiry handler to run even after Cancel() has been called. This will |
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184 occur in the case where DfcThread1 is preempted just before calling the |
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185 expiry handler for this timer and the preempting thread/ISR/IDFC calls |
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186 Cancel() on the timer. |
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187 |
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188 @pre Any context |
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189 @return TRUE if timer was actually cancelled |
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190 @return FALSE if timer was not cancelled - this could be because it was not |
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191 active or because its expiry handler was already running on |
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192 another CPU or in the timer DFC. |
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193 */ |
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194 EXPORT_C TBool NTimer::Cancel() |
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195 { |
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196 TBool result = TRUE; |
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197 TInt irq=NKern::DisableAllInterrupts(); |
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198 if (iState>ETransferring) // idle or transferring timers are not on a queue |
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199 Deque(); |
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200 switch (iState) |
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201 { |
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202 case ETransferring: // signal DFC to abort this iteration |
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203 TheTimerQ.iTransferringCancelled=TRUE; |
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204 break; |
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205 case ECritical: // signal DFC to abort this iteration |
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206 TheTimerQ.iCriticalCancelled=TRUE; |
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207 break; |
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208 case EFinal: |
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209 { |
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210 // Need to clear bit in iPresent if both final queues now empty |
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211 // NOTE: Timer might actually be on the completed queue rather than the final queue |
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212 // but the check is harmless in any case. |
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213 TInt i=iTriggerTime & NTimerQ::ETimerQMask; |
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214 NTimerQ::STimerQ& q=TheTimerQ.iTickQ[i]; |
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215 if (q.iIntQ.IsEmpty() && q.iDfcQ.IsEmpty()) |
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216 TheTimerQ.iPresent &= ~(1<<i); |
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217 break; |
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218 } |
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219 case EIdle: // nothing to do |
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220 result = FALSE; |
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221 case EHolding: // just deque |
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222 case EOrdered: // just deque |
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223 break; |
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224 } |
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225 iState=EIdle; |
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226 NKern::RestoreInterrupts(irq); |
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227 return result; |
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228 } |
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229 #endif |
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230 |
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231 |
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232 /** Check if a nanokernel timer is pending or not |
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233 |
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234 @return TRUE if the timer is pending (OneShot() etc. would return KErrInUse) |
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235 @return FALSE if the timer is idle (OneShot() etc. would succeed) |
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236 @pre Any context |
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237 |
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238 @publishedPartner |
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239 @prototype |
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240 */ |
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241 EXPORT_C TBool NTimer::IsPending() |
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242 { |
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243 return iState != EIdle; |
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244 } |
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245 |
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246 |
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247 /** Obtains the address of the nanokernel timer queue object. |
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248 |
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249 Not intended for general use. Intended only for base ports in order to get |
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250 the address used to call NTimerQ::Tick() with. |
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251 |
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252 @return The address of the nanokernel timer queue object |
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253 @pre Any context |
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254 */ |
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255 EXPORT_C TAny* NTimerQ::TimerAddress() |
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256 { |
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257 return &TheTimerQ; |
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258 } |
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259 |
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260 NTimerQ::NTimerQ() |
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261 : iDfc(NTimerQ::DfcFn,this,NULL,KTimerQDfcPriority) |
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262 { |
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263 // NOTE: All other members are initialised to zero since the single instance |
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264 // of NTimerQ resides in .bss |
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265 } |
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266 |
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267 void NTimerQ::Init1(TInt aTickPeriod) |
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268 { |
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269 TheTimerQ.iTickPeriod=aTickPeriod; |
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270 __KTRACE_OPT(KBOOT,DEBUGPRINT("NTimerQ::Init1 - period %d us",aTickPeriod)); |
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271 __KTRACE_OPT(KMEMTRACE, DEBUGPRINT("MT:P %d",aTickPeriod)); |
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272 } |
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273 |
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274 void NTimerQ::Init3(TDfcQue* aDfcQ) |
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275 { |
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276 __KTRACE_OPT(KBOOT,DEBUGPRINT("NTimerQ::Init3 DFCQ at %08x",aDfcQ)); |
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277 TheTimerQ.iDfc.SetDfcQ(aDfcQ); |
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278 } |
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279 |
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280 #ifndef __MSTIM_MACHINE_CODED__ |
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281 void NTimerQ::Add(NTimer* aTimer) |
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282 // |
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283 // Internal function to add a timer to the queue. |
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284 // Enter and return with all interrupts disabled. |
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285 // |
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286 { |
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287 TInt t=TInt(aTimer->iTriggerTime-iMsCount); |
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288 if (t<ENumTimerQueues) |
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289 AddFinal(aTimer); |
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290 else |
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291 { |
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292 // >=32ms to expiry, so put on holding queue |
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293 aTimer->iState=NTimer::EHolding; |
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294 iHoldingQ.Add(aTimer); |
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295 } |
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296 } |
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297 |
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298 void NTimerQ::AddFinal(NTimer* aTimer) |
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299 // |
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300 // Internal function to add a timer to the corresponding final queue. |
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301 // Enter and return with all interrupts disabled. |
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302 // |
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303 { |
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304 TInt i=aTimer->iTriggerTime & ETimerQMask; |
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305 SDblQue* pQ; |
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306 if (aTimer->iCompleteInDfc) |
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307 pQ=&iTickQ[i].iDfcQ; |
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308 else |
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309 pQ=&iTickQ[i].iIntQ; |
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310 iPresent |= (1<<i); |
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311 aTimer->iState=NTimer::EFinal; |
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312 pQ->Add(aTimer); |
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313 } |
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314 |
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315 void NTimerQ::DfcFn(TAny* aPtr) |
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316 { |
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317 ((NTimerQ*)aPtr)->Dfc(); |
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318 } |
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319 |
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320 void NTimerQ::Dfc() |
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321 // |
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322 // Do deferred timer queue processing and/or DFC completions |
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323 // |
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324 { |
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325 TInt irq; |
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326 |
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327 // First transfer entries on the Ordered queue to the Final queues |
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328 FOREVER |
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329 { |
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330 irq=NKern::DisableAllInterrupts(); |
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331 if (iOrderedQ.IsEmpty()) |
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332 break; |
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333 NTimer* pC=(NTimer*)iOrderedQ.First(); |
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334 TInt remain=pC->iTriggerTime-iMsCount; |
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335 if (remain>=ENumTimerQueues) |
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336 break; |
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337 |
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338 // If remaining time <32 ticks, add it to final queue; |
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339 // also if remain < 0 we've 'missed it' so add to final queue. |
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340 pC->Deque(); |
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341 AddFinal(pC); |
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342 NKern::RestoreInterrupts(irq); |
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343 __DEBUG_CALLBACK(0); |
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344 } |
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345 NKern::RestoreInterrupts(irq); |
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346 __DEBUG_CALLBACK(1); |
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347 |
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348 // Next transfer entries on the Holding queue to the Ordered queue or final queue |
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349 FOREVER |
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350 { |
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351 irq=NKern::DisableAllInterrupts(); |
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352 if (iHoldingQ.IsEmpty()) |
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353 break; |
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354 NTimer* pC=(NTimer*)iHoldingQ.First(); |
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355 pC->Deque(); |
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356 pC->iState=NTimer::ETransferring; |
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357 iTransferringCancelled=FALSE; |
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358 TUint32 trigger=pC->iTriggerTime; |
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359 if (TInt(trigger-iMsCount)<ENumTimerQueues) |
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360 { |
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361 // <32ms remaining so put it on final queue |
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362 AddFinal(pC); |
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363 } |
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364 else |
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365 { |
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366 FOREVER |
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367 { |
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368 NKern::RestoreInterrupts(irq); |
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369 __DEBUG_CALLBACK(2); |
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370 |
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371 // we now need to walk ordered queue to find correct position for pC |
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372 SDblQueLink* anchor=&iOrderedQ.iA; |
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373 iCriticalCancelled=FALSE; |
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374 irq=NKern::DisableAllInterrupts(); |
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375 NTimer* pN=(NTimer*)iOrderedQ.First(); |
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376 while (pN!=anchor && !iTransferringCancelled) |
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377 { |
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378 if ((pN->iTriggerTime-trigger)<0x80000000u) |
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379 break; // insert before pN |
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380 pN->iState=NTimer::ECritical; |
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381 NKern::RestoreInterrupts(irq); |
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382 __DEBUG_CALLBACK(3); |
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383 irq=NKern::DisableAllInterrupts(); |
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384 if (iCriticalCancelled) |
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385 break; |
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386 pN->iState=NTimer::EOrdered; |
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387 pN=(NTimer*)pN->iNext; |
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388 } |
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389 |
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390 if (iTransferringCancelled) |
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391 break; // this one has been cancelled, go on to next one |
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392 if (!iCriticalCancelled) |
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393 { |
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394 pC->InsertBefore(pN); |
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395 pC->iState=NTimer::EOrdered; |
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396 break; // done this one |
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397 } |
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398 } |
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399 } |
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400 NKern::RestoreInterrupts(irq); |
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401 __DEBUG_CALLBACK(4); |
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402 } |
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403 NKern::RestoreInterrupts(irq); |
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404 __DEBUG_CALLBACK(5); |
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405 |
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406 // Finally do call backs for timers which requested DFC callback |
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407 FOREVER |
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408 { |
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409 irq=NKern::DisableAllInterrupts(); |
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410 if (iCompletedQ.IsEmpty()) |
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411 break; |
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412 NTimer* pC=(NTimer*)iCompletedQ.First(); |
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413 pC->Deque(); |
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414 pC->iState=NTimer::EIdle; |
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415 TAny* p=pC->iPtr; |
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416 NTimerFn f=pC->iFunction; |
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417 NKern::RestoreInterrupts(irq); |
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418 __DEBUG_CALLBACK(7); |
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419 (*f)(p); |
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420 } |
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421 NKern::RestoreInterrupts(irq); |
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422 } |
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423 |
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424 |
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425 /** Tick over the nanokernel timer queue. |
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426 This function should be called by the base port in the system tick timer ISR. |
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427 It should not be called at any other time. |
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428 The value of 'this' to pass is the value returned by NTimerQ::TimerAddress(). |
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429 |
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430 @see NTimerQ::TimerAddress() |
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431 */ |
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432 EXPORT_C void NTimerQ::Tick() |
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433 { |
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434 #ifdef _DEBUG |
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435 // If there are threads waiting to be released by the tick, enqueue the dfc |
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436 if (!TheScheduler.iDelayedQ.IsEmpty()) |
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437 TheScheduler.iDelayDfc.Add(); |
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438 #endif |
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439 TheScheduler.TimesliceTick(); |
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440 TInt irq=NKern::DisableAllInterrupts(); |
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441 TInt i=iMsCount & ETimerQMask; |
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442 iMsCount++; |
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443 STimerQ* pQ=iTickQ+i; |
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444 iPresent &= ~(1<<i); |
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445 TBool doDfc=FALSE; |
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446 if (!pQ->iDfcQ.IsEmpty()) |
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447 { |
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448 // transfer DFC completions to completed queue and queue DFC |
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449 iCompletedQ.MoveFrom(&pQ->iDfcQ); |
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450 doDfc=TRUE; |
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451 } |
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452 if ((i&(ETimerQMask>>1))==0) |
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453 { |
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454 // Every 16 ticks we check if a DFC is required. |
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455 // This allows a DFC latency of up to 16 ticks before timers are missed. |
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456 if (!iHoldingQ.IsEmpty()) |
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457 doDfc=TRUE; // if holding queue nonempty, queue DFC to sort |
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458 else if (!iOrderedQ.IsEmpty()) |
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459 { |
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460 // if first ordered queue entry expires in <32ms, queue the DFC to transfer |
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461 NTimer* pC=(NTimer*)iOrderedQ.First(); |
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462 #ifdef __EPOC32__ |
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463 __ASSERT_WITH_MESSAGE_DEBUG(iMsCount<=pC->iTriggerTime, "iMsCount has exceeded pC->iTriggerTime; function called later than expected ","NKTimer::Tick()"); |
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464 #endif |
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465 if (TInt(pC->iTriggerTime-iMsCount)<ENumTimerQueues) |
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466 doDfc=TRUE; |
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467 } |
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468 } |
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469 if (!pQ->iIntQ.IsEmpty()) |
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470 { |
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471 // transfer ISR completions to a temporary queue |
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472 // careful here - higher priority interrupts could dequeue timers! |
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473 SDblQue q(&pQ->iIntQ,0); |
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474 while(!q.IsEmpty()) |
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475 { |
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476 NTimer* pC=(NTimer*)q.First(); |
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477 pC->Deque(); |
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478 pC->iState=NTimer::EIdle; |
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479 NKern::RestoreInterrupts(irq); |
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480 if (pC->iFunction) |
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481 (*pC->iFunction)(pC->iPtr); |
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482 else |
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483 ((TDfc*)(pC->iPtr))->Add(); |
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484 irq=NKern::DisableAllInterrupts(); |
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485 } |
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486 } |
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487 NKern::RestoreInterrupts(irq); |
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488 if (doDfc) |
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489 iDfc.Add(); |
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490 } |
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491 |
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492 |
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493 /** Return the number of ticks before the next nanokernel timer expiry. |
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494 May on occasion return a pessimistic estimate (i.e. too low). |
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495 Used by base port to disable the system tick interrupt when the system |
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496 is idle. |
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497 |
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498 @return The number of ticks before the next nanokernel timer expiry. |
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499 |
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500 @pre Interrupts must be disabled. |
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501 |
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502 @post Interrupts are disabled. |
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503 */ |
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504 EXPORT_C TInt NTimerQ::IdleTime() |
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505 { |
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506 CHECK_PRECONDITIONS(MASK_INTERRUPTS_DISABLED,"NTimerQ::IdleTime"); |
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507 #ifdef _DEBUG |
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508 // If there are threads waiting to be released by the tick we can't idle |
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509 if (!TheScheduler.iDelayedQ.IsEmpty()) |
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510 return 1; |
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511 #endif |
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512 NTimerQ& m=TheTimerQ; |
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513 TUint32 next=m.iMsCount; // number of next tick |
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514 TUint32 p=m.iPresent; |
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515 TInt r=KMaxTInt; |
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516 if (p) |
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517 { |
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518 // Final queues nonempty |
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519 TInt nx=next&0x1f; // number of next tick modulo 32 |
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520 p=(p>>nx)|(p<<(32-nx)); // rotate p right by nx (so lsb corresponds to next tick) |
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521 r=__e32_find_ls1_32(p); // find number of zeros before LS 1 |
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522 } |
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523 if (!m.iHoldingQ.IsEmpty()) |
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524 { |
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525 // Sort operation required - need to process next tick divisible by 16 |
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526 TInt nx=next&0x0f; // number of next tick modulo 16 |
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527 TInt r2=nx?(16-nx):0; // number of ticks before next divisible by 16 |
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528 if (r2<r) |
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529 r=r2; |
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530 } |
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531 if (!m.iOrderedQ.IsEmpty()) |
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532 { |
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533 // Timers present on ordered queue |
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534 NTimer* pC=(NTimer*)m.iOrderedQ.First(); |
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535 TUint32 tt=pC->iTriggerTime; |
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536 tt=(tt&~0x0f)-16; // time at which transfer to final queue would occur |
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537 TInt r3=(TInt)(tt-next); |
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538 if (r3<r) |
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539 r=r3; |
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540 } |
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541 return r; |
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542 } |
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543 #endif |
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544 |
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545 |
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546 /** Advance the nanokernel timer queue by the specified number of ticks. |
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547 It is assumed that no timers expire as a result of this. |
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548 Used by base port when system comes out of idle mode after disabling the |
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549 system tick interrupt to bring the timer queue up to date. |
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550 |
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551 @param aTicks Number of ticks skipped due to tick suppression |
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552 |
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553 @pre Interrupts must be disabled. |
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554 |
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555 @post Interrupts are disabled. |
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556 */ |
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557 EXPORT_C void NTimerQ::Advance(TInt aTicks) |
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558 { |
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559 CHECK_PRECONDITIONS(MASK_INTERRUPTS_DISABLED,"NTimerQ::Advance"); |
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560 TheTimerQ.iMsCount+=(TUint32)aTicks; |
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561 } |
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562 |
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563 |
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564 /** Returns the period of the nanokernel timer. |
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565 @return Period in microseconds |
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566 @pre any context |
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567 @see NTimer |
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568 */ |
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569 EXPORT_C TInt NKern::TickPeriod() |
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570 { |
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571 return TheTimerQ.iTickPeriod; |
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572 } |
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573 |
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574 |
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575 /** Converts a time interval to timer ticks. |
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576 |
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577 @param aMilliseconds time interval in milliseconds. |
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578 @return Number of nanokernel timer ticks. Non-integral results are rounded up. |
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579 |
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580 @pre aMilliseconds should be <=2147483 to avoid integer overflow. |
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581 @pre any context |
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582 */ |
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583 EXPORT_C TInt NKern::TimerTicks(TInt aMilliseconds) |
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584 { |
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585 __ASSERT_WITH_MESSAGE_DEBUG(aMilliseconds<=2147483,"aMilliseconds should be <=2147483","NKern::TimerTicks"); |
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586 TUint32 msp=TheTimerQ.iTickPeriod; |
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587 if (msp==1000) // will be true except on pathological hardware |
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588 return aMilliseconds; |
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589 TUint32 us=(TUint32)aMilliseconds*1000; |
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590 return (us+msp-1)/msp; |
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591 } |
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592 |