// SPDX-License-Identifier: GPL-2.0-or-later
/*
* ALSA sequencer Priority Queue
* Copyright (c) 1998-1999 by Frank van de Pol <[email protected]>
*/
#include <linux/time.h>
#include <linux/slab.h>
#include <sound/core.h>
#include "seq_timer.h"
#include "seq_prioq.h"
/* Implementation is a simple linked list for now...
This priority queue orders the events on timestamp. For events with an
equeal timestamp the queue behaves as a FIFO.
*
* +-------+
* Head --> | first |
* +-------+
* |next
* +-----v-+
* | |
* +-------+
* |
* +-----v-+
* | |
* +-------+
* |
* +-----v-+
* Tail --> | last |
* +-------+
*
*/
/* create new prioq (constructor) */
struct snd_seq_prioq *snd_seq_prioq_new(void)
{
struct snd_seq_prioq *f;
f = kzalloc(sizeof(*f), GFP_KERNEL);
if (!f)
return NULL;
spin_lock_init(&f->lock);
f->head = NULL;
f->tail = NULL;
f->cells = 0;
return f;
}
/* delete prioq (destructor) */
void snd_seq_prioq_delete(struct snd_seq_prioq **fifo)
{
struct snd_seq_prioq *f = *fifo;
*fifo = NULL;
if (f == NULL) {
pr_debug("ALSA: seq: snd_seq_prioq_delete() called with NULL prioq\n");
return;
}
/* release resources...*/
/*....................*/
if (f->cells > 0) {
/* drain prioQ */
while (f->cells > 0)
snd_seq_cell_free(snd_seq_prioq_cell_out(f, NULL));
}
kfree(f);
}
/* compare timestamp between events */
/* return 1 if a >= b; 0 */
static inline int compare_timestamp(struct snd_seq_event *a,
struct snd_seq_event *b)
{
if ((a->flags & SNDRV_SEQ_TIME_STAMP_MASK) == SNDRV_SEQ_TIME_STAMP_TICK) {
/* compare ticks */
return (snd_seq_compare_tick_time(&a->time.tick, &b->time.tick));
} else {
/* compare real time */
return (snd_seq_compare_real_time(&a->time.time, &b->time.time));
}
}
/* compare timestamp between events */
/* return negative if a < b;
* zero if a = b;
* positive if a > b;
*/
static inline int compare_timestamp_rel(struct snd_seq_event *a,
struct snd_seq_event *b)
{
if ((a->flags & SNDRV_SEQ_TIME_STAMP_MASK) == SNDRV_SEQ_TIME_STAMP_TICK) {
/* compare ticks */
if (a->time.tick > b->time.tick)
return 1;
else if (a->time.tick == b->time.tick)
return 0;
else
return -1;
} else {
/* compare real time */
if (a->time.time.tv_sec > b->time.time.tv_sec)
return 1;
else if (a->time.time.tv_sec == b->time.time.tv_sec) {
if (a->time.time.tv_nsec > b->time.time.tv_nsec)
return 1;
else if (a->time.time.tv_nsec == b->time.time.tv_nsec)
return 0;
else
return -1;
} else
return -1;
}
}
/* enqueue cell to prioq */
int snd_seq_prioq_cell_in(struct snd_seq_prioq * f,
struct snd_seq_event_cell * cell)
{
struct snd_seq_event_cell *cur, *prev;
int count;
int prior;
if (snd_BUG_ON(!f || !cell))
return -EINVAL;
/* check flags */
prior = (cell->event.flags & SNDRV_SEQ_PRIORITY_MASK);
guard(spinlock_irqsave)(&f->lock);
/* check if this element needs to inserted at the end (ie. ordered
data is inserted) This will be very likeley if a sequencer
application or midi file player is feeding us (sequential) data */
if (f->tail && !prior) {
if (compare_timestamp(&cell->event, &f->tail->event)) {
/* add new cell to tail of the fifo */
f->tail->next = cell;
f->tail = cell;
cell->next = NULL;
f->cells++;
return 0;
}
}
/* traverse list of elements to find the place where the new cell is
to be inserted... Note that this is a order n process ! */
prev = NULL; /* previous cell */
cur = f->head; /* cursor */
count = 10000; /* FIXME: enough big, isn't it? */
while (cur != NULL) {
/* compare timestamps */
int rel = compare_timestamp_rel(&cell->event, &cur->event);
if (rel < 0)
/* new cell has earlier schedule time, */
break;
else if (rel == 0 && prior)
/* equal schedule time and prior to others */
break;
/* new cell has equal or larger schedule time, */
/* move cursor to next cell */
prev = cur;
cur = cur->next;
if (! --count) {
pr_err("ALSA: seq: cannot find a pointer.. infinite loop?\n");
return -EINVAL;
}
}
/* insert it before cursor */
if (prev != NULL)
prev->next = cell;
cell->next = cur;
if (f->head == cur) /* this is the first cell, set head to it */
f->head = cell;
if (cur == NULL) /* reached end of the list */
f->tail = cell;
f->cells++;
return 0;
}
/* return 1 if the current time >= event timestamp */
static int event_is_ready(struct snd_seq_event *ev, void *current_time)
{
if ((ev->flags & SNDRV_SEQ_TIME_STAMP_MASK) == SNDRV_SEQ_TIME_STAMP_TICK)
return snd_seq_compare_tick_time(current_time, &ev->time.tick);
else
return snd_seq_compare_real_time(current_time, &ev->time.time);
}
/* dequeue cell from prioq */
struct snd_seq_event_cell *snd_seq_prioq_cell_out(struct snd_seq_prioq *f,
void *current_time)
{
struct snd_seq_event_cell *cell;
if (f == NULL) {
pr_debug("ALSA: seq: snd_seq_prioq_cell_in() called with NULL prioq\n");
return NULL;
}
guard(spinlock_irqsave)(&f->lock);
cell = f->head;
if (cell && current_time && !event_is_ready(&cell->event, current_time))
cell = NULL;
if (cell) {
f->head = cell->next;
/* reset tail if this was the last element */
if (f->tail == cell)
f->tail = NULL;
cell->next = NULL;
f->cells--;
}
return cell;
}
/* return number of events available in prioq */
int snd_seq_prioq_avail(struct snd_seq_prioq * f)
{
if (f == NULL) {
pr_debug("ALSA: seq: snd_seq_prioq_cell_in() called with NULL prioq\n");
return 0;
}
return f->cells;
}
/* remove cells matching with the condition */
static void prioq_remove_cells(struct snd_seq_prioq *f,
bool (*match)(struct snd_seq_event_cell *cell,
void *arg),
void *arg)
{
register struct snd_seq_event_cell *cell, *next;
struct snd_seq_event_cell *prev = NULL;
struct snd_seq_event_cell *freefirst = NULL, *freeprev = NULL, *freenext;
/* collect all removed cells */
scoped_guard(spinlock_irqsave, &f->lock) {
for (cell = f->head; cell; cell = next) {
next = cell->next;
if (!match(cell, arg)) {
prev = cell;
continue;
}
/* remove cell from prioq */
if (cell == f->head)
f->head = cell->next;
else
prev->next = cell->next;
if (cell == f->tail)
f->tail = cell->next;
f->cells--;
/* add cell to free list */
cell->next = NULL;
if (freefirst == NULL)
freefirst = cell;
else
freeprev->next = cell;
freeprev = cell;
}
}
/* remove selected cells */
while (freefirst) {
freenext = freefirst->next;
snd_seq_cell_free(freefirst);
freefirst = freenext;
}
}
struct prioq_match_arg {
int client;
int timestamp;
};
static inline bool prioq_match(struct snd_seq_event_cell *cell, void *arg)
{
struct prioq_match_arg *v = arg;
if (cell->event.source.client == v->client ||
cell->event.dest.client == v->client)
return true;
if (!v->timestamp)
return false;
switch (cell->event.flags & SNDRV_SEQ_TIME_STAMP_MASK) {
case SNDRV_SEQ_TIME_STAMP_TICK:
if (cell->event.time.tick)
return true;
break;
case SNDRV_SEQ_TIME_STAMP_REAL:
if (cell->event.time.time.tv_sec ||
cell->event.time.time.tv_nsec)
return true;
break;
}
return false;
}
/* remove cells for left client */
void snd_seq_prioq_leave(struct snd_seq_prioq *f, int client, int timestamp)
{
struct prioq_match_arg arg = { client, timestamp };
return prioq_remove_cells(f, prioq_match, &arg);
}
struct prioq_remove_match_arg {
int client;
struct snd_seq_remove_events *info;
};
static bool prioq_remove_match(struct snd_seq_event_cell *cell, void *arg)
{
struct prioq_remove_match_arg *v = arg;
struct snd_seq_event *ev = &cell->event;
struct snd_seq_remove_events *info = v->info;
int res;
if (ev->source.client != v->client)
return false;
if (info->remove_mode & SNDRV_SEQ_REMOVE_DEST) {
if (ev->dest.client != info->dest.client ||
ev->dest.port != info->dest.port)
return false;
}
if (info->remove_mode & SNDRV_SEQ_REMOVE_DEST_CHANNEL) {
if (! snd_seq_ev_is_channel_type(ev))
return false;
/* data.note.channel and data.control.channel are identical */
if (ev->data.note.channel != info->channel)
return false;
}
if (info->remove_mode & SNDRV_SEQ_REMOVE_TIME_AFTER) {
if (info->remove_mode & SNDRV_SEQ_REMOVE_TIME_TICK)
res = snd_seq_compare_tick_time(&ev->time.tick, &info->time.tick);
else
res = snd_seq_compare_real_time(&ev->time.time, &info->time.time);
if (!res)
return false;
}
if (info->remove_mode & SNDRV_SEQ_REMOVE_TIME_BEFORE) {
if (info->remove_mode & SNDRV_SEQ_REMOVE_TIME_TICK)
res = snd_seq_compare_tick_time(&ev->time.tick, &info->time.tick);
else
res = snd_seq_compare_real_time(&ev->time.time, &info->time.time);
if (res)
return false;
}
if (info->remove_mode & SNDRV_SEQ_REMOVE_EVENT_TYPE) {
if (ev->type != info->type)
return false;
}
if (info->remove_mode & SNDRV_SEQ_REMOVE_IGNORE_OFF) {
/* Do not remove off events */
switch (ev->type) {
case SNDRV_SEQ_EVENT_NOTEOFF:
/* case SNDRV_SEQ_EVENT_SAMPLE_STOP: */
return false;
default:
break;
}
}
if (info->remove_mode & SNDRV_SEQ_REMOVE_TAG_MATCH) {
if (info->tag != ev->tag)
return false;
}
return true;
}
/* remove cells matching remove criteria */
void snd_seq_prioq_remove_events(struct snd_seq_prioq * f, int client,
struct snd_seq_remove_events *info)
{
struct prioq_remove_match_arg arg = { client, info };
return prioq_remove_cells(f, prioq_remove_match, &arg);
}
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