// SPDX-License-Identifier: GPL-2.0-or-later
/*
* ALSA sequencer Timer
* Copyright (c) 1998-1999 by Frank van de Pol <[email protected]>
* Jaroslav Kysela <[email protected]>
*/
#include <sound/core.h>
#include <linux/slab.h>
#include "seq_timer.h"
#include "seq_queue.h"
#include "seq_info.h"
/* allowed sequencer timer frequencies, in Hz */
#define MIN_FREQUENCY 10
#define MAX_FREQUENCY 6250
#define DEFAULT_FREQUENCY 1000
#define SKEW_BASE 0x10000 /* 16bit shift */
static void snd_seq_timer_set_tick_resolution(struct snd_seq_timer *tmr)
{
unsigned int threshold =
tmr->tempo_base == 1000 ? 1000000 : 10000;
if (tmr->tempo < threshold)
tmr->tick.resolution = (tmr->tempo * tmr->tempo_base) / tmr->ppq;
else {
/* might overflow.. */
unsigned int s;
s = tmr->tempo % tmr->ppq;
s = (s * tmr->tempo_base) / tmr->ppq;
tmr->tick.resolution = (tmr->tempo / tmr->ppq) * tmr->tempo_base;
tmr->tick.resolution += s;
}
if (tmr->tick.resolution <= 0)
tmr->tick.resolution = 1;
snd_seq_timer_update_tick(&tmr->tick, 0);
}
/* create new timer (constructor) */
struct snd_seq_timer *snd_seq_timer_new(void)
{
struct snd_seq_timer *tmr;
tmr = kzalloc(sizeof(*tmr), GFP_KERNEL);
if (!tmr)
return NULL;
spin_lock_init(&tmr->lock);
/* reset setup to defaults */
snd_seq_timer_defaults(tmr);
/* reset time */
snd_seq_timer_reset(tmr);
return tmr;
}
/* delete timer (destructor) */
void snd_seq_timer_delete(struct snd_seq_timer **tmr)
{
struct snd_seq_timer *t = *tmr;
*tmr = NULL;
if (t == NULL) {
pr_debug("ALSA: seq: snd_seq_timer_delete() called with NULL timer\n");
return;
}
t->running = 0;
/* reset time */
snd_seq_timer_stop(t);
snd_seq_timer_reset(t);
kfree(t);
}
void snd_seq_timer_defaults(struct snd_seq_timer * tmr)
{
guard(spinlock_irqsave)(&tmr->lock);
/* setup defaults */
tmr->ppq = 96; /* 96 PPQ */
tmr->tempo = 500000; /* 120 BPM */
tmr->tempo_base = 1000; /* 1us */
snd_seq_timer_set_tick_resolution(tmr);
tmr->running = 0;
tmr->type = SNDRV_SEQ_TIMER_ALSA;
tmr->alsa_id.dev_class = seq_default_timer_class;
tmr->alsa_id.dev_sclass = seq_default_timer_sclass;
tmr->alsa_id.card = seq_default_timer_card;
tmr->alsa_id.device = seq_default_timer_device;
tmr->alsa_id.subdevice = seq_default_timer_subdevice;
tmr->preferred_resolution = seq_default_timer_resolution;
tmr->skew = tmr->skew_base = SKEW_BASE;
}
static void seq_timer_reset(struct snd_seq_timer *tmr)
{
/* reset time & songposition */
tmr->cur_time.tv_sec = 0;
tmr->cur_time.tv_nsec = 0;
tmr->tick.cur_tick = 0;
tmr->tick.fraction = 0;
}
void snd_seq_timer_reset(struct snd_seq_timer *tmr)
{
guard(spinlock_irqsave)(&tmr->lock);
seq_timer_reset(tmr);
}
/* called by timer interrupt routine. the period time since previous invocation is passed */
static void snd_seq_timer_interrupt(struct snd_timer_instance *timeri,
unsigned long resolution,
unsigned long ticks)
{
struct snd_seq_queue *q = timeri->callback_data;
struct snd_seq_timer *tmr;
if (q == NULL)
return;
tmr = q->timer;
if (tmr == NULL)
return;
scoped_guard(spinlock_irqsave, &tmr->lock) {
if (!tmr->running)
return;
resolution *= ticks;
if (tmr->skew != tmr->skew_base) {
/* FIXME: assuming skew_base = 0x10000 */
resolution = (resolution >> 16) * tmr->skew +
(((resolution & 0xffff) * tmr->skew) >> 16);
}
/* update timer */
snd_seq_inc_time_nsec(&tmr->cur_time, resolution);
/* calculate current tick */
snd_seq_timer_update_tick(&tmr->tick, resolution);
/* register actual time of this timer update */
ktime_get_ts64(&tmr->last_update);
}
/* check queues and dispatch events */
snd_seq_check_queue(q, 1, 0);
}
/* set current tempo */
int snd_seq_timer_set_tempo(struct snd_seq_timer * tmr, int tempo)
{
if (snd_BUG_ON(!tmr))
return -EINVAL;
if (tempo <= 0)
return -EINVAL;
guard(spinlock_irqsave)(&tmr->lock);
if ((unsigned int)tempo != tmr->tempo) {
tmr->tempo = tempo;
snd_seq_timer_set_tick_resolution(tmr);
}
return 0;
}
/* set current tempo, ppq and base in a shot */
int snd_seq_timer_set_tempo_ppq(struct snd_seq_timer *tmr, int tempo, int ppq,
unsigned int tempo_base)
{
int changed;
if (snd_BUG_ON(!tmr))
return -EINVAL;
if (tempo <= 0 || ppq <= 0)
return -EINVAL;
/* allow only 10ns or 1us tempo base for now */
if (tempo_base && tempo_base != 10 && tempo_base != 1000)
return -EINVAL;
guard(spinlock_irqsave)(&tmr->lock);
if (tmr->running && (ppq != tmr->ppq)) {
/* refuse to change ppq on running timers */
/* because it will upset the song position (ticks) */
pr_debug("ALSA: seq: cannot change ppq of a running timer\n");
return -EBUSY;
}
changed = (tempo != tmr->tempo) || (ppq != tmr->ppq);
tmr->tempo = tempo;
tmr->ppq = ppq;
tmr->tempo_base = tempo_base ? tempo_base : 1000;
if (changed)
snd_seq_timer_set_tick_resolution(tmr);
return 0;
}
/* set current tick position */
int snd_seq_timer_set_position_tick(struct snd_seq_timer *tmr,
snd_seq_tick_time_t position)
{
if (snd_BUG_ON(!tmr))
return -EINVAL;
guard(spinlock_irqsave)(&tmr->lock);
tmr->tick.cur_tick = position;
tmr->tick.fraction = 0;
return 0;
}
/* set current real-time position */
int snd_seq_timer_set_position_time(struct snd_seq_timer *tmr,
snd_seq_real_time_t position)
{
if (snd_BUG_ON(!tmr))
return -EINVAL;
snd_seq_sanity_real_time(&position);
guard(spinlock_irqsave)(&tmr->lock);
tmr->cur_time = position;
return 0;
}
/* set timer skew */
int snd_seq_timer_set_skew(struct snd_seq_timer *tmr, unsigned int skew,
unsigned int base)
{
if (snd_BUG_ON(!tmr))
return -EINVAL;
/* FIXME */
if (base != SKEW_BASE) {
pr_debug("ALSA: seq: invalid skew base 0x%x\n", base);
return -EINVAL;
}
guard(spinlock_irqsave)(&tmr->lock);
tmr->skew = skew;
return 0;
}
int snd_seq_timer_open(struct snd_seq_queue *q)
{
struct snd_timer_instance *t;
struct snd_seq_timer *tmr;
char str[32];
int err;
tmr = q->timer;
if (snd_BUG_ON(!tmr))
return -EINVAL;
if (tmr->timeri)
return -EBUSY;
sprintf(str, "sequencer queue %i", q->queue);
if (tmr->type != SNDRV_SEQ_TIMER_ALSA) /* standard ALSA timer */
return -EINVAL;
if (tmr->alsa_id.dev_class != SNDRV_TIMER_CLASS_SLAVE)
tmr->alsa_id.dev_sclass = SNDRV_TIMER_SCLASS_SEQUENCER;
t = snd_timer_instance_new(str);
if (!t)
return -ENOMEM;
t->callback = snd_seq_timer_interrupt;
t->callback_data = q;
t->flags |= SNDRV_TIMER_IFLG_AUTO;
err = snd_timer_open(t, &tmr->alsa_id, q->queue);
if (err < 0 && tmr->alsa_id.dev_class != SNDRV_TIMER_CLASS_SLAVE) {
if (tmr->alsa_id.dev_class != SNDRV_TIMER_CLASS_GLOBAL ||
tmr->alsa_id.device != SNDRV_TIMER_GLOBAL_SYSTEM) {
struct snd_timer_id tid;
memset(&tid, 0, sizeof(tid));
tid.dev_class = SNDRV_TIMER_CLASS_GLOBAL;
tid.dev_sclass = SNDRV_TIMER_SCLASS_SEQUENCER;
tid.card = -1;
tid.device = SNDRV_TIMER_GLOBAL_SYSTEM;
err = snd_timer_open(t, &tid, q->queue);
}
}
if (err < 0) {
pr_err("ALSA: seq fatal error: cannot create timer (%i)\n", err);
snd_timer_instance_free(t);
return err;
}
scoped_guard(spinlock_irq, &tmr->lock) {
if (tmr->timeri)
err = -EBUSY;
else
tmr->timeri = t;
}
if (err < 0) {
snd_timer_close(t);
snd_timer_instance_free(t);
return err;
}
return 0;
}
int snd_seq_timer_close(struct snd_seq_queue *q)
{
struct snd_seq_timer *tmr;
struct snd_timer_instance *t;
tmr = q->timer;
if (snd_BUG_ON(!tmr))
return -EINVAL;
scoped_guard(spinlock_irq, &tmr->lock) {
t = tmr->timeri;
tmr->timeri = NULL;
}
if (t) {
snd_timer_close(t);
snd_timer_instance_free(t);
}
return 0;
}
static int seq_timer_stop(struct snd_seq_timer *tmr)
{
if (! tmr->timeri)
return -EINVAL;
if (!tmr->running)
return 0;
tmr->running = 0;
snd_timer_pause(tmr->timeri);
return 0;
}
int snd_seq_timer_stop(struct snd_seq_timer *tmr)
{
guard(spinlock_irqsave)(&tmr->lock);
return seq_timer_stop(tmr);
}
static int initialize_timer(struct snd_seq_timer *tmr)
{
struct snd_timer *t;
unsigned long freq;
t = tmr->timeri->timer;
if (!t)
return -EINVAL;
freq = tmr->preferred_resolution;
if (!freq)
freq = DEFAULT_FREQUENCY;
else if (freq < MIN_FREQUENCY)
freq = MIN_FREQUENCY;
else if (freq > MAX_FREQUENCY)
freq = MAX_FREQUENCY;
tmr->ticks = 1;
if (!(t->hw.flags & SNDRV_TIMER_HW_SLAVE)) {
unsigned long r = snd_timer_resolution(tmr->timeri);
if (r) {
tmr->ticks = (unsigned int)(1000000000uL / (r * freq));
if (! tmr->ticks)
tmr->ticks = 1;
}
}
tmr->initialized = 1;
return 0;
}
static int seq_timer_start(struct snd_seq_timer *tmr)
{
if (! tmr->timeri)
return -EINVAL;
if (tmr->running)
seq_timer_stop(tmr);
seq_timer_reset(tmr);
if (initialize_timer(tmr) < 0)
return -EINVAL;
snd_timer_start(tmr->timeri, tmr->ticks);
tmr->running = 1;
ktime_get_ts64(&tmr->last_update);
return 0;
}
int snd_seq_timer_start(struct snd_seq_timer *tmr)
{
guard(spinlock_irqsave)(&tmr->lock);
return seq_timer_start(tmr);
}
static int seq_timer_continue(struct snd_seq_timer *tmr)
{
if (! tmr->timeri)
return -EINVAL;
if (tmr->running)
return -EBUSY;
if (! tmr->initialized) {
seq_timer_reset(tmr);
if (initialize_timer(tmr) < 0)
return -EINVAL;
}
snd_timer_start(tmr->timeri, tmr->ticks);
tmr->running = 1;
ktime_get_ts64(&tmr->last_update);
return 0;
}
int snd_seq_timer_continue(struct snd_seq_timer *tmr)
{
guard(spinlock_irqsave)(&tmr->lock);
return seq_timer_continue(tmr);
}
/* return current 'real' time. use timeofday() to get better granularity. */
snd_seq_real_time_t snd_seq_timer_get_cur_time(struct snd_seq_timer *tmr,
bool adjust_ktime)
{
snd_seq_real_time_t cur_time;
guard(spinlock_irqsave)(&tmr->lock);
cur_time = tmr->cur_time;
if (adjust_ktime && tmr->running) {
struct timespec64 tm;
ktime_get_ts64(&tm);
tm = timespec64_sub(tm, tmr->last_update);
cur_time.tv_nsec += tm.tv_nsec;
cur_time.tv_sec += tm.tv_sec;
snd_seq_sanity_real_time(&cur_time);
}
return cur_time;
}
/* TODO: use interpolation on tick queue (will only be useful for very
high PPQ values) */
snd_seq_tick_time_t snd_seq_timer_get_cur_tick(struct snd_seq_timer *tmr)
{
guard(spinlock_irqsave)(&tmr->lock);
return tmr->tick.cur_tick;
}
#ifdef CONFIG_SND_PROC_FS
/* exported to seq_info.c */
void snd_seq_info_timer_read(struct snd_info_entry *entry,
struct snd_info_buffer *buffer)
{
int idx;
struct snd_seq_queue *q;
struct snd_seq_timer *tmr;
struct snd_timer_instance *ti;
unsigned long resolution;
for (idx = 0; idx < SNDRV_SEQ_MAX_QUEUES; idx++) {
q = queueptr(idx);
if (q == NULL)
continue;
scoped_guard(mutex, &q->timer_mutex) {
tmr = q->timer;
if (!tmr)
break;
ti = tmr->timeri;
if (!ti)
break;
snd_iprintf(buffer, "Timer for queue %i : %s\n", q->queue, ti->timer->name);
resolution = snd_timer_resolution(ti) * tmr->ticks;
snd_iprintf(buffer, " Period time : %lu.%09lu\n", resolution / 1000000000, resolution % 1000000000);
snd_iprintf(buffer, " Skew : %u / %u\n", tmr->skew, tmr->skew_base);
}
queuefree(q);
}
}
#endif /* CONFIG_SND_PROC_FS */
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