1 files changed, 308 insertions, 0 deletions
diff --git a/bsd_eth_drivers/libbsdport/rtems_taskqueue.c b/bsd_eth_drivers/libbsdport/rtems_taskqueue.c
new file mode 100644
index 0000000..97153ca
--- /dev/null
+++ b/bsd_eth_drivers/libbsdport/rtems_taskqueue.c
@@ -0,0 +1,308 @@
+#include <rtems.h>
+#include <rtems/error.h>
+
+#include <rtems/rtems_bsdnet.h>
+#include <rtems/rtems_bsdnet_internal.h>
+
+#include "taskqueue.h"
+
+/*
+#define STATIC static
+*/
+#undef  DEBUG
+
+#ifdef DEBUG
+#include <stdio.h>
+#ifndef STATIC
+#define STATIC
+#endif
+#else
+#ifndef STATIC
+#define STATIC static
+#endif
+#endif
+
+#define TQ_WAKE_EVENT RTEMS_EVENT_0
+
+/* This implementation is extremely simple; we assume
+ * that all taskqueues (and as a matter of fact there is
+ * only a single one) are manipulated with the rtems
+ * bsdnet semaphore held. I.e.,
+ *   taskqueue_enqueue()
+ *   taskqueue_drain()
+ *   etc.
+ * are called from an environment that holds the
+ * bsdnet semaphore.
+ * Likewise, the thread that works the taskqueue
+ * holds the semaphore while doing so.
+ *
+ */
+
+/* use single-linked list; 'drain' which would benefit from
+ * double-linked list is seldom used and performance doesn't
+ * matter much there. OTOH, the frequent case of working
+ * the list + enqueueing is more efficient for the single-linked
+ * list.
+struct task {
+	struct task *ta_next;
+	int		     ta_pending;
+	int		     ta_priority;
+	task_fn      ta_fn;
+	void        *ta_fn_arg;
+};
+ */
+
+struct taskqueue {
+	struct task anchor;
+	struct task *tail;
+	tq_enq_fn   enq_fn;
+	void       *enq_fn_arg;
+	rtems_id    tid;
+};
+
+
+STATIC struct taskqueue the_taskqueue = {
+	{ 0, 0, 0, 0, 0 },
+	&the_taskqueue.anchor,
+	taskqueue_thread_enqueue,
+	&taskqueue_fast,
+	0
+};
+
+struct taskqueue *taskqueue_fast = &the_taskqueue;
+
+struct taskqueue *
+taskqueue_create(const char *name, int mflags, tq_enq_fn enq_fn, void *arg)
+{
+	if ( enq_fn != taskqueue_thread_enqueue )
+		rtems_panic("rtems_taskqueue: attempt to create non-standard TQ; implementation needs to be modified\n");
+	return &the_taskqueue;
+}
+
+struct taskqueue *
+taskqueue_create_fast(const char *name, int mflags, tq_enq_fn enq_fn, void *arg)
+{
+	return taskqueue_create(name, mflags, enq_fn, arg);
+}
+
+/* taskqueue_enqueue must be allowed from an ISR;
+ * hence, all critical list manipulation must lock out
+ * interrupts...
+ */
+int
+taskqueue_enqueue(struct taskqueue *tq, struct task *ta)
+{
+rtems_interrupt_level l;
+
+rtems_interrupt_disable(l);
+	if ( 0 == ta->ta_pending ++ ) {
+		/* hook into list */
+		ta->ta_next       = 0;
+		tq->tail->ta_next = ta;
+		tq->tail          = ta;
+	}
+	tq->enq_fn(tq->enq_fn_arg);
+rtems_interrupt_enable(l);
+	return 0;
+}
+
+void
+taskqueue_thread_enqueue(void *ctxt)
+{
+int                   dopost;
+/* pointer-to-pointer is what bsd provides; we currently
+ * follow the scheme even we don't directly use the argument
+ * passed to taskqueue_create...
+ */
+struct taskqueue *tq = *(struct taskqueue **)ctxt;
+	/* If this is the first entry on the list then the
+	 * task needs to be notified...
+	 */
+	dopost = ( tq->anchor.ta_next == tq->tail && 1 == tq->tail->ta_pending );
+
+	if ( dopost )
+		rtems_event_send(tq->tid, TQ_WAKE_EVENT);
+}
+
+/* Returns 0 on success */
+int
+taskqueue_start_threads(struct taskqueue **ptq, int count, int prio, const char *fmt, ...)
+{
+	if ( count != 1 )
+		rtems_panic("rtems_taskqueue: taskqueue_start_threads cannot currently deal with count != 1\n");
+	
+	/* Do (non thread-safe) lazy init as a fallback */
+	if ( ! the_taskqueue.tid )
+		rtems_taskqueue_initialize();
+	return 0;
+}
+
+void
+taskqueue_drain(struct taskqueue *tq, struct task *ta)
+{
+rtems_interrupt_level l;
+struct task *p, *q;
+int    i;
+
+	/* find predecessor; searching the list should be
+	 * safe; an ISR might append a new record to the tail
+	 * while we are working but that should be OK.
+	 */
+	for ( p = &tq->anchor; (q = p->ta_next); p=q ) {
+		if ( q == ta ) {
+		rtems_interrupt_disable(l);
+			/* found; do work */
+			/* remember 'pending' count and extract */
+			i              = ta->ta_pending;
+			ta->ta_pending = 0;
+			p->ta_next     = ta->ta_next;
+			ta->ta_next    = 0;
+			/* adjust tail */
+			if ( tq->tail == q )
+				tq->tail = p;
+		rtems_interrupt_enable(l);
+			for ( ; i>0; i-- ) {
+				ta->ta_fn(ta->ta_fn_arg, i);
+			}
+			return;
+		}
+	}
+}
+
+/* work the task queue and return
+ * nonzero if the list is not empty
+ * (which means that some callback has
+ * rescheduled itself)
+ */
+static void *
+taskqueue_work(struct taskqueue *tq)
+{
+rtems_interrupt_level l;
+struct task   *p, *q;
+task_fn        f;
+void        *arg;
+int            i;
+
+/* work off a temporary list in case any callback reschedules
+ * itself or if new tasks are queued from an ISR.
+ */
+rtems_interrupt_disable(l);
+	p = tq->anchor.ta_next;
+
+	tq->anchor.ta_next = 0;
+	tq->tail           = &tq->anchor;
+rtems_interrupt_enable(l);
+
+	while ( (q=p) ) {
+	rtems_interrupt_disable(l);
+		i = q->ta_pending;
+		q->ta_pending = 0;
+		/* extract */
+		p          = q->ta_next;
+		q->ta_next = 0;
+		f          = q->ta_fn;
+		arg        = q->ta_fn_arg;
+	rtems_interrupt_enable(l);
+		for ( ; i>0; i-- ) {
+			f(arg, i);
+		}
+	}
+	return tq->anchor.ta_next;
+}
+
+void
+taskqueue_free(struct taskqueue *tq)
+{
+	taskqueue_work(tq);
+}
+
+static void
+taskqueueDoWork(void *arg)
+{
+struct taskqueue *tq = arg;
+rtems_event_set  evs;
+rtems_status_code sc;
+	while ( 1 ) {
+		sc = rtems_bsdnet_event_receive(TQ_WAKE_EVENT, RTEMS_EVENT_ANY | RTEMS_WAIT, RTEMS_NO_TIMEOUT, &evs);
+		if ( RTEMS_SUCCESSFUL != sc ) {
+			rtems_error(sc,"rtems_taskqueue: taskqueueDoWork() unable to receive wakup event\n");
+			rtems_panic("Can't proceed\n");
+		}
+		if ( taskqueue_work(tq) ) {
+#if 0
+			/* chance to reschedule */
+			rtems_bsdnet_semaphore_release();
+			rtems_task_wake_after(0);
+			rtems_bsdnet_semaphore_obtain();
+#else
+			/* hopefully, releasing the semaphore (as part of bsdnet_event_receive)
+			 * and obtaining the event (which has been posted already)
+			 * yields the CPU if necessary...
+			 */
+#endif
+		}
+	}
+}
+
+#ifdef DEBUG
+struct task_dbg {
+	struct task t;
+	char        *nm;
+};
+
+struct task_dbg taskA = {
+	{0},
+	"taskA"
+};
+
+struct task_dbg taskB = {
+	{0},
+	"taskB"
+};
+
+struct task_dbg taskC = {
+	{0},
+	"taskC"
+};
+
+static void the_task_fn(void *arg, int pending)
+{
+struct task_dbg *td = arg;
+	printf("%s (pending: %i)\n", td->nm, pending);
+	/* Test rescheduling */
+	if ( pending > 3 )
+		taskqueue_enqueue(&the_taskqueue,&td->t);
+}
+
+void taskqueue_dump()
+{
+struct task *p;
+	printf("Anchor %p, Tail %p\n", &the_taskqueue.anchor, the_taskqueue.tail);
+	for ( p = the_taskqueue.anchor.ta_next; p; p=p->ta_next ) {
+		printf("%p: (pending %2i, next %p)\n",
+			p, p->ta_pending, p->ta_next);
+	}
+}
+#endif
+
+rtems_id
+rtems_taskqueue_initialize()
+{
+#ifdef DEBUG
+	TASK_INIT( &taskA.t, 0, the_task_fn, &taskA );
+	TASK_INIT( &taskB.t, 0, the_task_fn, &taskB );
+	TASK_INIT( &taskC.t, 0, the_task_fn, &taskC );
+#endif
+	if ( ! the_taskqueue.tid )
+		the_taskqueue.tid = rtems_bsdnet_newproc("tskq", 10000, taskqueueDoWork, &the_taskqueue);
+	return the_taskqueue.tid;
+}
+
+#ifdef DEBUG
+void
+_cexpModuleInitialize(void *u)
+{
+	rtems_bsdnet_initialize_network();
+	the_taskqueue.tid = rtems_taskqueue_initialize();
+}
+#endif