[da162c8] | 1 | /** |
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| 2 | * @file |
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| 3 | * |
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| 4 | * @ingroup rtems_bsd_rtems |
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| 5 | * |
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| 6 | * @brief TODO. |
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| 7 | */ |
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| 8 | |
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| 9 | /* |
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[8420b94] | 10 | * COPYRIGHT (c) 2012. |
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| 11 | * On-Line Applications Research Corporation (OAR). |
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| 12 | * All Rights Reserved. |
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[da162c8] | 13 | * |
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[8420b94] | 14 | * Redistribution and use in source and binary forms, with or without |
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| 15 | * modification, are permitted provided that the following conditions |
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| 16 | * are met: |
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| 17 | * 1. Redistributions of source code must retain the above copyright |
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| 18 | * notice, this list of conditions and the following disclaimer. |
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| 19 | * 2. Redistributions in binary form must reproduce the above copyright |
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| 20 | * notice, this list of conditions and the following disclaimer in the |
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| 21 | * documentation and/or other materials provided with the distribution. |
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| 22 | * |
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| 23 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND |
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| 24 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
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| 25 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
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| 26 | * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE |
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| 27 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
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| 28 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
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| 29 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
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| 30 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
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| 31 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
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| 32 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
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| 33 | * SUCH DAMAGE. |
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[da162c8] | 34 | */ |
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| 35 | |
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| 36 | #include <sys/cdefs.h> |
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| 37 | __FBSDID("$FreeBSD$"); |
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| 38 | |
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| 39 | #include <rtems.h> |
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| 40 | #include <rtems/error.h> |
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| 41 | #include <freebsd/machine/rtems-bsd-taskqueue.h> |
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| 42 | |
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| 43 | /* |
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| 44 | #define STATIC static |
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| 45 | */ |
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| 46 | #undef DEBUG |
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| 47 | |
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| 48 | #ifdef DEBUG |
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| 49 | #include <stdio.h> |
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| 50 | #ifndef STATIC |
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| 51 | #define STATIC |
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| 52 | #endif |
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| 53 | #else |
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| 54 | #ifndef STATIC |
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| 55 | #define STATIC static |
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| 56 | #endif |
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| 57 | #endif |
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| 58 | |
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| 59 | #define TQ_WAKE_EVENT RTEMS_EVENT_0 |
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| 60 | |
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| 61 | /* This implementation is extremely simple; we assume |
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| 62 | * that all taskqueues (and as a matter of fact there is |
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| 63 | * only a single one) are manipulated with the rtems |
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| 64 | * bsdnet semaphore held. I.e., |
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| 65 | * taskqueue_enqueue() |
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| 66 | * taskqueue_drain() |
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| 67 | * etc. |
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| 68 | * are called from an environment that holds the |
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| 69 | * bsdnet semaphore. |
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| 70 | * Likewise, the thread that works the taskqueue |
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| 71 | * holds the semaphore while doing so. |
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| 72 | * |
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| 73 | */ |
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| 74 | |
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| 75 | /* use single-linked list; 'drain' which would benefit from |
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| 76 | * double-linked list is seldom used and performance doesn't |
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| 77 | * matter much there. OTOH, the frequent case of working |
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| 78 | * the list + enqueueing is more efficient for the single-linked |
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| 79 | * list. |
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| 80 | struct task { |
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| 81 | struct task *ta_next; |
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| 82 | int ta_pending; |
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| 83 | int ta_priority; |
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| 84 | task_fn ta_fn; |
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| 85 | void *ta_fn_arg; |
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| 86 | }; |
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| 87 | */ |
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| 88 | |
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| 89 | struct taskqueue { |
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| 90 | struct task anchor; |
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| 91 | struct task *tail; |
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| 92 | tq_enq_fn enq_fn; |
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| 93 | void *enq_fn_arg; |
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| 94 | rtems_id tid; |
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| 95 | }; |
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| 96 | |
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| 97 | |
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| 98 | STATIC struct taskqueue the_taskqueue = { |
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| 99 | { 0, 0, 0, 0, 0 }, |
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| 100 | &the_taskqueue.anchor, |
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| 101 | taskqueue_thread_enqueue, |
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| 102 | &taskqueue_fast, |
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| 103 | 0 |
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| 104 | }; |
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| 105 | |
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| 106 | struct taskqueue *taskqueue_fast = &the_taskqueue; |
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| 107 | struct taskqueue *taskqueue_swi = NULL; |
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| 108 | |
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| 109 | struct taskqueue * |
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| 110 | taskqueue_create(const char *name, int mflags, tq_enq_fn enq_fn, void *arg) |
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| 111 | { |
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| 112 | if ( enq_fn != taskqueue_thread_enqueue ) |
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| 113 | rtems_panic("rtems_taskqueue: attempt to create non-standard TQ; implementation needs to be modified\n"); |
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| 114 | return &the_taskqueue; |
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| 115 | } |
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| 116 | |
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| 117 | struct taskqueue * |
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| 118 | taskqueue_create_fast(const char *name, int mflags, tq_enq_fn enq_fn, void *arg) |
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| 119 | { |
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| 120 | return taskqueue_create(name, mflags, enq_fn, arg); |
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| 121 | } |
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| 122 | |
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| 123 | /* taskqueue_enqueue must be allowed from an ISR; |
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| 124 | * hence, all critical list manipulation must lock out |
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| 125 | * interrupts... |
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| 126 | */ |
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| 127 | int |
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| 128 | taskqueue_enqueue(struct taskqueue *tq, struct task *ta) |
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| 129 | { |
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| 130 | rtems_interrupt_level l; |
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| 131 | |
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| 132 | rtems_interrupt_disable(l); |
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| 133 | if ( 0 == ta->ta_pending ++ ) { |
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| 134 | /* hook into list */ |
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| 135 | ta->ta_next = 0; |
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| 136 | tq->tail->ta_next = ta; |
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| 137 | tq->tail = ta; |
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| 138 | } |
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| 139 | tq->enq_fn(tq->enq_fn_arg); |
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| 140 | rtems_interrupt_enable(l); |
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| 141 | return 0; |
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| 142 | } |
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| 143 | |
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[8f6d129] | 144 | int |
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| 145 | taskqueue_enqueue_fast(struct taskqueue *queue, struct task *task) |
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| 146 | { |
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| 147 | return taskqueue_enqueue(queue, task); |
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| 148 | } |
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| 149 | |
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[da162c8] | 150 | void |
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| 151 | taskqueue_thread_enqueue(void *ctxt) |
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| 152 | { |
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| 153 | int dopost; |
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| 154 | /* pointer-to-pointer is what bsd provides; we currently |
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| 155 | * follow the scheme even we don't directly use the argument |
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| 156 | * passed to taskqueue_create... |
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| 157 | */ |
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| 158 | struct taskqueue *tq = *(struct taskqueue **)ctxt; |
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| 159 | /* If this is the first entry on the list then the |
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| 160 | * task needs to be notified... |
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| 161 | */ |
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| 162 | dopost = ( tq->anchor.ta_next == tq->tail && 1 == tq->tail->ta_pending ); |
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| 163 | |
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| 164 | if ( dopost ) |
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| 165 | rtems_event_send(tq->tid, TQ_WAKE_EVENT); |
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| 166 | } |
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| 167 | |
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| 168 | /* Returns 0 on success */ |
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| 169 | int |
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| 170 | taskqueue_start_threads(struct taskqueue **ptq, int count, int prio, const char *fmt, ...) |
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| 171 | { |
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| 172 | if ( count != 1 ) |
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| 173 | rtems_panic("rtems_taskqueue: taskqueue_start_threads cannot currently deal with count != 1\n"); |
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| 174 | |
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| 175 | /* Do (non thread-safe) lazy init as a fallback */ |
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| 176 | if ( ! the_taskqueue.tid ) |
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| 177 | rtems_taskqueue_initialize(); |
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| 178 | return 0; |
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| 179 | } |
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| 180 | |
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| 181 | void |
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| 182 | taskqueue_drain(struct taskqueue *tq, struct task *ta) |
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| 183 | { |
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| 184 | rtems_interrupt_level l; |
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| 185 | struct task *p, *q; |
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| 186 | int i; |
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| 187 | |
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| 188 | /* find predecessor; searching the list should be |
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| 189 | * safe; an ISR might append a new record to the tail |
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| 190 | * while we are working but that should be OK. |
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| 191 | */ |
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| 192 | for ( p = &tq->anchor; (q = p->ta_next); p=q ) { |
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| 193 | if ( q == ta ) { |
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| 194 | rtems_interrupt_disable(l); |
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| 195 | /* found; do work */ |
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| 196 | /* remember 'pending' count and extract */ |
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| 197 | i = ta->ta_pending; |
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| 198 | ta->ta_pending = 0; |
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| 199 | p->ta_next = ta->ta_next; |
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| 200 | ta->ta_next = 0; |
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| 201 | /* adjust tail */ |
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| 202 | if ( tq->tail == q ) |
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| 203 | tq->tail = p; |
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| 204 | rtems_interrupt_enable(l); |
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| 205 | for ( ; i>0; i-- ) { |
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| 206 | ta->ta_fn(ta->ta_fn_arg, i); |
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| 207 | } |
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| 208 | return; |
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| 209 | } |
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| 210 | } |
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| 211 | } |
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| 212 | |
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| 213 | /* work the task queue and return |
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| 214 | * nonzero if the list is not empty |
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| 215 | * (which means that some callback has |
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| 216 | * rescheduled itself) |
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| 217 | */ |
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| 218 | static void * |
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| 219 | taskqueue_work(struct taskqueue *tq) |
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| 220 | { |
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| 221 | rtems_interrupt_level l; |
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| 222 | struct task *p, *q; |
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| 223 | task_fn f; |
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| 224 | void *arg; |
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| 225 | int i; |
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| 226 | |
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| 227 | /* work off a temporary list in case any callback reschedules |
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| 228 | * itself or if new tasks are queued from an ISR. |
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| 229 | */ |
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| 230 | rtems_interrupt_disable(l); |
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| 231 | p = tq->anchor.ta_next; |
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| 232 | |
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| 233 | tq->anchor.ta_next = 0; |
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| 234 | tq->tail = &tq->anchor; |
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| 235 | rtems_interrupt_enable(l); |
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| 236 | |
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| 237 | while ( (q=p) ) { |
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| 238 | rtems_interrupt_disable(l); |
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| 239 | i = q->ta_pending; |
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| 240 | q->ta_pending = 0; |
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| 241 | /* extract */ |
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| 242 | p = q->ta_next; |
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| 243 | q->ta_next = 0; |
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| 244 | f = q->ta_fn; |
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| 245 | arg = q->ta_fn_arg; |
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| 246 | rtems_interrupt_enable(l); |
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| 247 | for ( ; i>0; i-- ) { |
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| 248 | f(arg, i); |
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| 249 | } |
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| 250 | } |
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| 251 | return tq->anchor.ta_next; |
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| 252 | } |
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| 253 | |
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| 254 | void |
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| 255 | taskqueue_free(struct taskqueue *tq) |
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| 256 | { |
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| 257 | taskqueue_work(tq); |
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| 258 | } |
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| 259 | |
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| 260 | static void |
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| 261 | taskqueueDoWork(void *arg) |
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| 262 | { |
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| 263 | struct taskqueue *tq = arg; |
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| 264 | rtems_event_set evs; |
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| 265 | rtems_status_code sc; |
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| 266 | while ( 1 ) { |
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[134df2e] | 267 | sc = rtems_event_receive(TQ_WAKE_EVENT, RTEMS_EVENT_ANY | RTEMS_WAIT, RTEMS_NO_TIMEOUT, &evs); |
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[da162c8] | 268 | if ( RTEMS_SUCCESSFUL != sc ) { |
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| 269 | rtems_error(sc,"rtems_taskqueue: taskqueueDoWork() unable to receive wakup event\n"); |
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| 270 | rtems_panic("Can't proceed\n"); |
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| 271 | } |
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| 272 | if ( taskqueue_work(tq) ) { |
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| 273 | #if 0 |
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| 274 | /* chance to reschedule */ |
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| 275 | rtems_bsdnet_semaphore_release(); |
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| 276 | rtems_task_wake_after(0); |
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| 277 | rtems_bsdnet_semaphore_obtain(); |
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| 278 | #else |
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| 279 | /* hopefully, releasing the semaphore (as part of bsdnet_event_receive) |
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| 280 | * and obtaining the event (which has been posted already) |
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| 281 | * yields the CPU if necessary... |
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| 282 | */ |
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| 283 | #endif |
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| 284 | } |
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| 285 | } |
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| 286 | } |
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| 287 | |
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| 288 | #ifdef DEBUG |
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| 289 | struct task_dbg { |
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| 290 | struct task t; |
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| 291 | char *nm; |
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| 292 | }; |
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| 293 | |
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| 294 | struct task_dbg taskA = { |
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| 295 | {0}, |
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| 296 | "taskA" |
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| 297 | }; |
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| 298 | |
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| 299 | struct task_dbg taskB = { |
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| 300 | {0}, |
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| 301 | "taskB" |
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| 302 | }; |
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| 303 | |
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| 304 | struct task_dbg taskC = { |
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| 305 | {0}, |
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| 306 | "taskC" |
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| 307 | }; |
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| 308 | |
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| 309 | static void the_task_fn(void *arg, int pending) |
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| 310 | { |
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| 311 | struct task_dbg *td = arg; |
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| 312 | printf("%s (pending: %i)\n", td->nm, pending); |
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| 313 | /* Test rescheduling */ |
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| 314 | if ( pending > 3 ) |
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| 315 | taskqueue_enqueue(&the_taskqueue,&td->t); |
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| 316 | } |
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| 317 | |
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| 318 | void taskqueue_dump() |
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| 319 | { |
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| 320 | struct task *p; |
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| 321 | printf("Anchor %p, Tail %p\n", &the_taskqueue.anchor, the_taskqueue.tail); |
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| 322 | for ( p = the_taskqueue.anchor.ta_next; p; p=p->ta_next ) { |
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| 323 | printf("%p: (pending %2i, next %p)\n", |
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| 324 | p, p->ta_pending, p->ta_next); |
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| 325 | } |
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| 326 | } |
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| 327 | #endif |
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| 328 | |
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| 329 | rtems_id |
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| 330 | rtems_taskqueue_initialize() |
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| 331 | { |
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| 332 | #ifdef DEBUG |
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| 333 | TASK_INIT( &taskA.t, 0, the_task_fn, &taskA ); |
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| 334 | TASK_INIT( &taskB.t, 0, the_task_fn, &taskB ); |
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| 335 | TASK_INIT( &taskC.t, 0, the_task_fn, &taskC ); |
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| 336 | #endif |
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| 337 | if ( ! the_taskqueue.tid ) |
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| 338 | the_taskqueue.tid = rtems_bsdnet_newproc("tskq", 10000, taskqueueDoWork, &the_taskqueue); |
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| 339 | return the_taskqueue.tid; |
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| 340 | } |
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| 341 | |
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| 342 | #ifdef DEBUG |
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| 343 | void |
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| 344 | _cexpModuleInitialize(void *u) |
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| 345 | { |
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| 346 | rtems_bsdnet_initialize_network(); |
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| 347 | the_taskqueue.tid = rtems_taskqueue_initialize(); |
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| 348 | } |
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| 349 | #endif |
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