scoutos / prex-0.9.0 / sys / kern / irq.c @ 03e9c04a
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1 | 03e9c04a | Brad Neuman | /*-
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2 | * Copyright (c) 2005-2007, Kohsuke Ohtani
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3 | * All rights reserved.
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4 | *
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5 | * Redistribution and use in source and binary forms, with or without
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6 | * modification, are permitted provided that the following conditions
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7 | * are met:
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8 | * 1. Redistributions of source code must retain the above copyright
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9 | * notice, this list of conditions and the following disclaimer.
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10 | * 2. Redistributions in binary form must reproduce the above copyright
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11 | * notice, this list of conditions and the following disclaimer in the
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12 | * documentation and/or other materials provided with the distribution.
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13 | * 3. Neither the name of the author nor the names of any co-contributors
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14 | * may be used to endorse or promote products derived from this software
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15 | * without specific prior written permission.
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16 | *
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17 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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18 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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19 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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20 | * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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21 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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22 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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23 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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24 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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25 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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26 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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27 | * SUCH DAMAGE.
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28 | */
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29 | |||
30 | /*
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31 | * irq.c - interrupt request management routines.
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32 | */
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33 | |||
34 | /**
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35 | * We define the following two different types of interrupt services
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36 | * in order to improve real-time performance.
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37 | *
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38 | * - Interrupt Service Routine (ISR)
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39 | *
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40 | * ISR is started by an actual hardware interrupt. The associated
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41 | * interrupt is disabled in Interrupt Control Unit (ICU), and CPU
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42 | * interrupt is enabled while ISR runs.
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43 | * If ISR determines that the corresponding device generated the
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44 | * interrupt, ISR must program the device to stop that interrupt.
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45 | * Then, ISR should do minimum I/O operation and return control as
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46 | * quickly as possible. ISR will run within a context of the thread
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47 | * running when interrupt occurs. So, only few kernel services are
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48 | * available within ISR.
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49 | *
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50 | * - Interrupt Service Thread (IST)
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51 | *
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52 | * IST is automatically activated if ISR returns INT_CONTINUE. It
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53 | * will be called when the system enters safer condition than ISR.
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54 | * A device driver should use IST to do heavy I/O operation as much
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55 | * as possible. Since ISR for the same IRQ line may be invoked during
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56 | * IST, the shared data, resources, and device registers must be
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57 | * synchronized by disabling interrupts. IST does not have to be
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58 | * reentrant because it is not interrupted by same IST itself.
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59 | */
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60 | |||
61 | #include <kernel.h> |
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62 | #include <event.h> |
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63 | #include <kmem.h> |
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64 | #include <sched.h> |
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65 | #include <thread.h> |
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66 | #include <irq.h> |
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67 | #include <hal.h> |
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68 | |||
69 | /* forward declarations */
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70 | static void irq_thread(void *); |
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71 | |||
72 | static struct irq *irq_table[MAXIRQS]; /* IRQ descriptor table */ |
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73 | |||
74 | /*
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75 | * irq_attach - attach ISR and IST to the specified interrupt.
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76 | *
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77 | * Returns irq handle, or panic on failure. The interrupt of
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78 | * attached irq will be unmasked (enabled) in this routine.
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79 | * TODO: Interrupt sharing is not supported, for now.
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80 | */
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81 | irq_t |
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82 | irq_attach(int vector, int pri, int shared, |
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83 | int (*isr)(void *), void (*ist)(void *), void *data) |
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84 | { |
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85 | struct irq *irq;
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86 | int mode;
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87 | |||
88 | ASSERT(isr != NULL);
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89 | |||
90 | sched_lock(); |
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91 | if ((irq = kmem_alloc(sizeof(*irq))) == NULL) |
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92 | panic("irq_attach");
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93 | |||
94 | memset(irq, 0, sizeof(*irq)); |
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95 | irq->vector = vector; |
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96 | irq->priority = pri; |
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97 | irq->isr = isr; |
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98 | irq->ist = ist; |
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99 | irq->data = data; |
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100 | |||
101 | if (ist != IST_NONE) {
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102 | /*
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103 | * Create a new thread for IST.
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104 | */
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105 | irq->thread = kthread_create(&irq_thread, irq, ISTPRI(pri)); |
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106 | if (irq->thread == NULL) |
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107 | panic("irq_attach");
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108 | |||
109 | event_init(&irq->istevt, "interrupt");
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110 | } |
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111 | irq_table[vector] = irq; |
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112 | mode = shared ? IMODE_LEVEL : IMODE_EDGE; |
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113 | interrupt_setup(vector, mode); |
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114 | interrupt_unmask(vector, pri); |
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115 | |||
116 | sched_unlock(); |
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117 | DPRINTF(("IRQ%d attached priority=%d\n", vector, pri));
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118 | return irq;
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119 | } |
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120 | |||
121 | /*
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122 | * Detach an interrupt handler from the interrupt chain.
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123 | * The detached interrupt will be masked off if nobody
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124 | * attaches to it, anymore.
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125 | */
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126 | void
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127 | irq_detach(irq_t irq) |
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128 | { |
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129 | ASSERT(irq != NULL);
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130 | ASSERT(irq->vector < MAXIRQS); |
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131 | |||
132 | interrupt_mask(irq->vector); |
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133 | irq_table[irq->vector] = NULL;
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134 | if (irq->thread != NULL) |
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135 | kthread_terminate(irq->thread); |
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136 | |||
137 | kmem_free(irq); |
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138 | } |
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139 | |||
140 | /*
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141 | * Interrupt service thread.
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142 | * This is a common dispatcher to all interrupt threads.
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143 | */
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144 | static void |
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145 | irq_thread(void *arg)
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146 | { |
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147 | void (*fn)(void *); |
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148 | void *data;
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149 | struct irq *irq;
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150 | |||
151 | splhigh(); |
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152 | |||
153 | irq = (struct irq *)arg;
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154 | fn = irq->ist; |
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155 | data = irq->data; |
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156 | |||
157 | for (;;) {
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158 | if (irq->istreq <= 0) { |
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159 | /*
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160 | * Since the interrupt is disabled above,
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161 | * an interrupt for this vector keeps
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162 | * pending until this thread enters sleep
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163 | * state. Thus, we don't lose any IST
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164 | * requests even if the interrupt is fired
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165 | * here.
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166 | */
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167 | sched_sleep(&irq->istevt); |
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168 | } |
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169 | irq->istreq--; |
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170 | ASSERT(irq->istreq >= 0);
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171 | |||
172 | /*
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173 | * Call IST
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174 | */
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175 | spl0(); |
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176 | (*fn)(data); |
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177 | splhigh(); |
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178 | } |
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179 | /* NOTREACHED */
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180 | } |
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181 | |||
182 | /*
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183 | * Interrupt handler.
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184 | *
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185 | * This routine will call the corresponding ISR for the
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186 | * requested interrupt vector. HAL code must call this
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187 | * routine with scheduler locked.
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188 | */
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189 | void
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190 | irq_handler(int vector)
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191 | { |
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192 | struct irq *irq;
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193 | int rc;
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194 | |||
195 | irq = irq_table[vector]; |
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196 | if (irq == NULL) { |
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197 | DPRINTF(("Random interrupt ignored\n"));
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198 | return;
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199 | } |
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200 | ASSERT(irq->isr != NULL);
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201 | |||
202 | /* Profile */
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203 | irq->count++; |
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204 | |||
205 | /*
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206 | * Call ISR
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207 | */
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208 | rc = (*irq->isr)(irq->data); |
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209 | |||
210 | if (rc == INT_CONTINUE) {
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211 | /*
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212 | * Kick IST
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213 | */
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214 | ASSERT(irq->ist != IST_NONE); |
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215 | irq->istreq++; |
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216 | sched_wakeup(&irq->istevt); |
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217 | ASSERT(irq->istreq != 0);
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218 | } |
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219 | } |
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220 | |||
221 | /*
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222 | * Return irq information.
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223 | */
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224 | int
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225 | irq_info(struct irqinfo *info)
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226 | { |
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227 | int vec = info->cookie;
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228 | int found = 0; |
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229 | struct irq *irq;
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230 | |||
231 | while (vec < MAXIRQS) {
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232 | if (irq_table[vec]) {
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233 | found = 1;
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234 | break;
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235 | } |
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236 | vec++; |
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237 | } |
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238 | if (!found)
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239 | return ESRCH;
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240 | |||
241 | irq = irq_table[vec]; |
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242 | info->vector = irq->vector; |
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243 | info->count = irq->count; |
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244 | info->priority = irq->priority; |
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245 | info->istreq = irq->istreq; |
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246 | info->thread = irq->thread; |
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247 | info->cookie = vec + 1;
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248 | return 0; |
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249 | } |
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250 | |||
251 | /*
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252 | * Start interrupt processing.
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253 | */
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254 | void
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255 | irq_init(void)
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256 | { |
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257 | |||
258 | interrupt_init(); |
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259 | |||
260 | /* Enable interrupts */
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261 | spl0(); |
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262 | } |