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/* TDMA Scheduler Implementation */
/* (C) 2010 by Harald Welte <laforge@gnumonks.org>
*
* All Rights Reserved
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
*/
#include <stdint.h>
#include <stdio.h>
#include <string.h>
#include <defines.h>
#include <debug.h>
#include <osmocom/gsm/gsm_utils.h>
#include <layer1/tdma_sched.h>
#include <layer1/sync.h>
#include <calypso/dsp.h>
/* dummy function to mark end of set */
int tdma_end_set(__unused uint8_t p1, __unused uint8_t p2,
__unused uint16_t p3)
{
return 0;
}
static uint8_t wrap_bucket(uint8_t offset)
{
uint16_t bucket;
bucket = (l1s.tdma_sched.cur_bucket + offset)
% ARRAY_SIZE(l1s.tdma_sched.bucket);
return bucket;
}
/* Schedule an item at 'frame_offset' TDMA frames in the future */
int tdma_schedule(uint8_t frame_offset, tdma_sched_cb *cb,
uint8_t p1, uint8_t p2, uint16_t p3, int16_t prio)
{
struct tdma_scheduler *sched = &l1s.tdma_sched;
uint8_t bucket_nr = wrap_bucket(frame_offset);
struct tdma_sched_bucket *bucket = &sched->bucket[bucket_nr];
struct tdma_sched_item *sched_item;
if (bucket->num_items >= ARRAY_SIZE(bucket->item)) {
puts("tdma_schedule bucket overflow\n");
return -1;
}
sched_item = &bucket->item[bucket->num_items++];
sched_item->cb = cb;
sched_item->p1 = p1;
sched_item->p2 = p2;
sched_item->p3 = p3;
sched_item->prio = prio;
return 0;
}
/* Schedule a set of items starting from 'frame_offset' TDMA frames in the future */
int tdma_schedule_set(uint8_t frame_offset, const struct tdma_sched_item *item_set, uint16_t p3)
{
struct tdma_scheduler *sched = &l1s.tdma_sched;
uint8_t bucket_nr = wrap_bucket(frame_offset);
int i, j;
for (i = 0, j = 0; 1; i++) {
const struct tdma_sched_item *sched_item = &item_set[i];
struct tdma_sched_bucket *bucket = &sched->bucket[bucket_nr];
if (sched_item->cb == &tdma_end_set) {
/* end of scheduler set, return */
break;
}
if (sched_item->cb == NULL) {
/* advance to next bucket (== TDMA frame) */
bucket_nr = wrap_bucket(++frame_offset);
j++;
continue;
}
/* check for bucket overflow */
if (bucket->num_items >= ARRAY_SIZE(bucket->item)) {
puts("tdma_schedule bucket overflow\n");
return -1;
}
/* copy the item from the set into the current bucket item position */
memcpy(&bucket->item[bucket->num_items], sched_item, sizeof(*sched_item));
bucket->item[bucket->num_items].p3 = p3;
bucket->num_items++;
}
return j;
}
/* Advance TDMA scheduler to the next bucket */
void tdma_sched_advance(void)
{
struct tdma_scheduler *sched = &l1s.tdma_sched;
uint8_t next_bucket;
/* advance to the next bucket */
next_bucket = wrap_bucket(1);
sched->cur_bucket = next_bucket;
}
/* Scan current frame scheduled items for flags */
uint16_t tdma_sched_flag_scan(void)
{
struct tdma_scheduler *sched = &l1s.tdma_sched;
struct tdma_sched_bucket *bucket;
int i;
uint16_t flags = 0;
/* determine current bucket */
bucket = &sched->bucket[sched->cur_bucket];
/* iterate over items in this bucket and call callback function */
for (i=0; i<bucket->num_items; i++) {
struct tdma_sched_item *item = &bucket->item[i];
flags |= item->flags;
}
return flags;
}
/* Sort a bucket entries by priority */
static void _tdma_sched_bucket_sort(struct tdma_sched_bucket *bucket, int *seq)
{
int i, j, k;
struct tdma_sched_item *item_i, *item_j;
/* initial sequence */
/* we need all the items because some call back may schedule
* new call backs 'on the fly' */
for (i=0; i<TDMASCHED_NUM_CB; i++)
seq[i] = i;
/* iterate over items in this bucket and sort them */
for (i=0; i<bucket->num_items; i++)
{
item_i = &bucket->item[seq[i]];
for (j=i+1; j<bucket->num_items; j++)
{
item_j = &bucket->item[seq[j]];
if (item_i->prio > item_j->prio)
{
item_i = item_j;
k = seq[i];
seq[i] = seq[j];
seq[j] = k;
}
}
}
}
/* Execute pre-scheduled events for current frame */
int tdma_sched_execute(void)
{
struct tdma_scheduler *sched = &l1s.tdma_sched;
struct tdma_sched_bucket *bucket;
int i, num_events = 0;
int seq[TDMASCHED_NUM_CB];
/* determine current bucket */
bucket = &sched->bucket[sched->cur_bucket];
/* get sequence in priority order */
_tdma_sched_bucket_sort(bucket, seq);
/* iterate over items in this bucket and call callback function */
for (i = 0; i < bucket->num_items; i++) {
struct tdma_sched_item *item = &bucket->item[seq[i]];
int rc;
num_events++;
rc = item->cb(item->p1, item->p2, item->p3);
if (rc < 0) {
printf("Error %d during processing of item %u of bucket %u\n",
rc, i, sched->cur_bucket);
return rc;
}
/* if the cb() we just called has scheduled more items for the
* current TDMA, bucket->num_items will have increased and we
* will simply continue to execute them as intended. Priorities
* won't work though ! */
}
/* clear/reset the bucket */
bucket->num_items = 0;
/* return number of items that we called */
return num_events;
}
void tdma_sched_reset(void)
{
struct tdma_scheduler *sched = &l1s.tdma_sched;
unsigned int bucket_nr;
for (bucket_nr = 0; bucket_nr < ARRAY_SIZE(sched->bucket); bucket_nr++) {
struct tdma_sched_bucket *bucket = &sched->bucket[bucket_nr];
/* current bucket will be reset by iteration code above! */
if (bucket_nr != sched->cur_bucket)
bucket->num_items = 0;
}
/* Don't reset cur_bucket, as it would upset the bucket iteration code
* in tdma_sched_execute() */
}
void tdma_sched_dump(void)
{
unsigned int i;
printf("\n(%2u)", l1s.tdma_sched.cur_bucket);
for (i = 0; i < ARRAY_SIZE(l1s.tdma_sched.bucket); i++) {
int bucket_nr = wrap_bucket(i);
struct tdma_sched_bucket *bucket = &l1s.tdma_sched.bucket[bucket_nr];
printf("%u:", bucket->num_items);
}
putchar('\n');
}
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