* Copyright (c) 2007 Jared D. McNeill <jmcneill@invisible.ca>

/* $NetBSD: pad.c,v 1.85 2023/05/27 14:51:47 nat Exp $ */

/*-
* Copyright (c) 2007 Jared D. McNeill <[email protected]>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: pad.c,v 1.85 2023/05/27 14:51:47 nat Exp $");

#include <sys/param.h>
#include <sys/types.h>

#include <sys/audioio.h>
#include <sys/buf.h>
#include <sys/condvar.h>
#include <sys/conf.h>
#include <sys/device.h>
#include <sys/file.h>
#include <sys/filedesc.h>
#include <sys/kauth.h>
#include <sys/kernel.h>
#include <sys/kmem.h>
#include <sys/module.h>
#include <sys/poll.h>
#include <sys/proc.h>
#include <sys/select.h>
#include <sys/stat.h>
#include <sys/vnode.h>

#include <dev/audio/audio_if.h>
#include <dev/audio/audiovar.h>

#include <dev/pad/padvar.h>

#include "ioconf.h"

/* #define PAD_DEBUG */
#ifdef PAD_DEBUG
#define DPRINTF(fmt...) printf(fmt)
#else
#define DPRINTF(fmt...) /**/
#endif

#define PADFREQ 44100
#define PADCHAN 2
#define PADPREC 16

typedef struct pad_block {
uint8_t *pb_ptr;
int pb_len;
} pad_block_t;

enum {
PAD_OUTPUT_CLASS,
PAD_INPUT_CLASS,
PAD_OUTPUT_MASTER_VOLUME,
PAD_INPUT_DAC_VOLUME,
PAD_ENUM_LAST,
};

static int pad_match(device_t, cfdata_t, void *);
static void pad_attach(device_t, device_t, void *);
static int pad_detach(device_t, int);
static void pad_childdet(device_t, device_t);

static int pad_query_format(void *, audio_format_query_t *);
static int pad_set_format(void *, int,
const audio_params_t *, const audio_params_t *,
audio_filter_reg_t *, audio_filter_reg_t *);
static int pad_start_output(void *, void *, int,
void (*)(void *), void *);
static int pad_halt_output(void *);
static int pad_getdev(void *, struct audio_device *);
static int pad_set_port(void *, mixer_ctrl_t *);
static int pad_get_port(void *, mixer_ctrl_t *);
static int pad_query_devinfo(void *, mixer_devinfo_t *);
static int pad_get_props(void *);
static void pad_get_locks(void *, kmutex_t **, kmutex_t **);

static void pad_done_output(void *);
static void pad_swvol_codec(audio_filter_arg_t *);

static void pad_close(struct pad_softc *);
static int pad_read(struct pad_softc *, off_t *, struct uio *,
kauth_cred_t, int);

static int fops_pad_close(struct file *);
static int fops_pad_read(struct file *, off_t *, struct uio *,
kauth_cred_t, int);
static int fops_pad_write(struct file *, off_t *, struct uio *,
kauth_cred_t, int);
static int fops_pad_ioctl(struct file *, u_long, void *);
static int fops_pad_kqfilter(struct file *, struct knote *);
static int fops_pad_poll(struct file *, int);
static int fops_pad_stat(struct file *, struct stat *);
static int fops_pad_mmap(struct file *, off_t *, size_t, int, int *, int *,
struct uvm_object **, int *);

static const struct audio_hw_if pad_hw_if = {
.query_format = pad_query_format,
.set_format = pad_set_format,
.start_output = pad_start_output,
.halt_output = pad_halt_output,
.getdev = pad_getdev,
.set_port = pad_set_port,
.get_port = pad_get_port,
.query_devinfo = pad_query_devinfo,
.get_props = pad_get_props,
.get_locks = pad_get_locks,
};

#define PAD_NFORMATS 1
static const struct audio_format pad_formats[PAD_NFORMATS] = {
{
.mode = AUMODE_PLAY,
.encoding = AUDIO_ENCODING_SLINEAR_LE,
.validbits = PADPREC,
.precision = PADPREC,
.channels = PADCHAN,
.channel_mask = AUFMT_STEREO,
.frequency_type = 1,
.frequency = { PADFREQ },
},
};

extern void padattach(int);

static int pad_add_block(struct pad_softc *, uint8_t *, int);
static int pad_get_block(struct pad_softc *, pad_block_t *, int, int);

static dev_type_open(pad_open);

const struct cdevsw pad_cdevsw = {
.d_open = pad_open,
.d_close = noclose,
.d_read = noread,
.d_write = nowrite,
.d_ioctl = noioctl,
.d_stop = nostop,
.d_tty = notty,
.d_poll = nopoll,
.d_mmap = nommap,
.d_kqfilter = nokqfilter,
.d_discard = nodiscard,
.d_flag = D_OTHER | D_MPSAFE,
};

const struct fileops pad_fileops = {
.fo_name = "pad",
.fo_read = fops_pad_read,
.fo_write = fops_pad_write,
.fo_ioctl = fops_pad_ioctl,
.fo_fcntl = fnullop_fcntl,
.fo_stat = fops_pad_stat,
.fo_poll = fops_pad_poll,
.fo_close = fops_pad_close,
.fo_mmap = fops_pad_mmap,
.fo_kqfilter = fops_pad_kqfilter,
.fo_restart = fnullop_restart
};

CFATTACH_DECL2_NEW(pad, sizeof(struct pad_softc),
pad_match, pad_attach, pad_detach,
NULL, NULL, pad_childdet);

void
padattach(int n)
{
int error;

error = config_cfattach_attach(pad_cd.cd_name, &pad_ca);
if (error) {
aprint_error("%s: couldn't register cfattach: %d\n",
pad_cd.cd_name, error);
config_cfdriver_detach(&pad_cd);
return;
}
}

static int
pad_match(device_t parent, cfdata_t data, void *opaque)
{

return 1;
}

static void
pad_attach(device_t parent, device_t self, void *opaque)
{
struct pad_softc *sc = device_private(self);

KASSERT(KERNEL_LOCKED_P());

aprint_normal_dev(self, "outputs: 44100Hz, 16-bit, stereo\n");

sc->sc_dev = self;

cv_init(&sc->sc_condvar, device_xname(sc->sc_dev));
mutex_init(&sc->sc_lock, MUTEX_DEFAULT, IPL_NONE);
mutex_init(&sc->sc_intr_lock, MUTEX_DEFAULT, IPL_SOFTCLOCK);
callout_init(&sc->sc_pcallout, CALLOUT_MPSAFE);
callout_setfunc(&sc->sc_pcallout, pad_done_output, sc);

sc->sc_swvol = 255;
sc->sc_buflen = 0;
sc->sc_rpos = sc->sc_wpos = 0;
sc->sc_audiodev = audio_attach_mi(&pad_hw_if, sc, sc->sc_dev);

if (!pmf_device_register(sc->sc_dev, NULL, NULL))
aprint_error_dev(sc->sc_dev,
"couldn't establish power handler\n");

sc->sc_open = 1;
}

static int
pad_detach(device_t self, int flags)
{
struct pad_softc *sc = device_private(self);
int cmaj, mn;
int error;

KASSERT(KERNEL_LOCKED_P());

/* Prevent detach without going through close -- e.g., drvctl. */
if (sc->sc_open)
return EBUSY;

error = config_detach_children(self, flags);
if (error)
return error;

cmaj = cdevsw_lookup_major(&pad_cdevsw);
mn = device_unit(sc->sc_dev);
vdevgone(cmaj, mn, mn, VCHR);

pmf_device_deregister(sc->sc_dev);

callout_destroy(&sc->sc_pcallout);
mutex_destroy(&sc->sc_lock);
mutex_destroy(&sc->sc_intr_lock);
cv_destroy(&sc->sc_condvar);

return 0;
}

static void
pad_childdet(device_t self, device_t child)
{
struct pad_softc *sc = device_private(self);

KASSERT(KERNEL_LOCKED_P());

if (child == sc->sc_audiodev)
sc->sc_audiodev = NULL;
}

static int
pad_add_block(struct pad_softc *sc, uint8_t *blk, int blksize)
{
int foff, flen, tlen;

KASSERT(blksize >= 0);
KASSERT(mutex_owned(&sc->sc_intr_lock));

if (blksize > PAD_BUFSIZE ||
sc->sc_buflen > PAD_BUFSIZE - (unsigned)blksize)
return ENOBUFS;

foff = sc->sc_wpos;
if (sc->sc_wpos + blksize <= PAD_BUFSIZE) {
flen = blksize;
tlen = 0;
} else {
flen = PAD_BUFSIZE - sc->sc_wpos;
tlen = blksize - flen;
}

sc->sc_wpos = foff + blksize;
if (sc->sc_wpos >= PAD_BUFSIZE)
sc->sc_wpos -= PAD_BUFSIZE;

/*
* release interrupt lock for bulk copy to audio buffer
*/
mutex_exit(&sc->sc_intr_lock);
memcpy(sc->sc_audiobuf + foff, blk, flen);
memcpy(sc->sc_audiobuf, blk + flen, tlen);
mutex_enter(&sc->sc_intr_lock);

sc->sc_buflen += blksize;
cv_broadcast(&sc->sc_condvar);

return 0;
}

static int
pad_get_block(struct pad_softc *sc, pad_block_t *pb, int maxblksize, int dowait)
{
int l, blksize, error;

KASSERT(maxblksize > 0);
KASSERT(mutex_owned(&sc->sc_intr_lock));

if (sc->sc_buflen == 0 && !dowait)
return EAGAIN;

while (sc->sc_buflen == 0) {
DPRINTF("%s: wait\n", __func__);
error = cv_wait_sig(&sc->sc_condvar, &sc->sc_intr_lock);
DPRINTF("%s: wake up %d\n", __func__, err);
if (error)
return error;
}
blksize = uimin(maxblksize, sc->sc_buflen);

pb->pb_ptr = (sc->sc_audiobuf + sc->sc_rpos);
if (sc->sc_rpos + blksize < PAD_BUFSIZE) {
pb->pb_len = blksize;
sc->sc_rpos += blksize;
} else {
l = PAD_BUFSIZE - sc->sc_rpos;
pb->pb_len = l;
sc->sc_rpos = 0;
}
sc->sc_buflen -= pb->pb_len;

return 0;
}

static int
pad_open(dev_t dev, int flags, int fmt, struct lwp *l)
{
struct file *fp = NULL;
device_t self;
struct pad_softc *sc = NULL;
cfdata_t cf = NULL;
int error, fd;

error = fd_allocfile(&fp, &fd);
if (error)
goto out;

cf = kmem_alloc(sizeof(*cf), KM_SLEEP);
cf->cf_name = pad_cd.cd_name;
cf->cf_atname = pad_cd.cd_name;
cf->cf_unit = 0;
cf->cf_fstate = FSTATE_STAR;

self = config_attach_pseudo(cf);
if (self == NULL) {
error = ENXIO;
goto out;
}
sc = device_private(self);
KASSERT(sc->sc_dev == self);
cf = NULL;

error = fd_clone(fp, fd, flags, &pad_fileops, sc);
KASSERT(error == EMOVEFD);
fp = NULL;
sc = NULL;

out: if (sc)
pad_close(sc);
if (cf)
kmem_free(cf, sizeof(*cf));
if (fp)
fd_abort(curproc, fp, fd);
return error;
}

static void
pad_close(struct pad_softc *sc)
{
device_t self = sc->sc_dev;
cfdata_t cf = device_cfdata(self);

/*
* XXX This is not quite enough to prevent racing with drvctl
* detach. What can happen:
*
* cpu0 cpu1
*
* pad_close
* take kernel lock
* sc->sc_open = 0
* drop kernel lock
* wait for config_misc_lock
* drvctl detach
* take kernel lock
* drop kernel lock
* wait for config_misc_lock
* retake kernel lock
* drop config_misc_lock
* take config_misc_lock
* wait for kernel lock
* pad_detach (sc_open=0 already)
* free device
* drop kernel lock
* use device after free
*
* We need a way to grab a reference to the device so it won't
* be freed until we're done -- it's OK if we config_detach
* twice as long as it's idempotent, but not OK if the first
* config_detach frees the struct device before the second one
* has finished handling it.
*/
KERNEL_LOCK(1, NULL);
KASSERT(sc->sc_open);
sc->sc_open = 0;
(void)config_detach(self, DETACH_FORCE);
KERNEL_UNLOCK_ONE(NULL);

kmem_free(cf, sizeof(*cf));
}

static int
fops_pad_close(struct file *fp)
{
struct pad_softc *sc = fp->f_pad;

pad_close(sc);

return 0;
}

static int
fops_pad_poll(struct file *fp, int events)
{

return POLLERR;
}

static int
fops_pad_kqfilter(struct file *fp, struct knote *kn)
{
struct pad_softc *sc = fp->f_pad;
dev_t dev;

dev = makedev(cdevsw_lookup_major(&pad_cdevsw),
device_unit(sc->sc_dev));

return seltrue_kqfilter(dev, kn);
}

static int
fops_pad_ioctl(struct file *fp, u_long cmd, void *data)
{

return ENODEV;
}

static int
fops_pad_stat(struct file *fp, struct stat *st)
{
struct pad_softc *sc = fp->f_pad;

memset(st, 0, sizeof(*st));

st->st_dev = makedev(cdevsw_lookup_major(&pad_cdevsw),
device_unit(sc->sc_dev));

st->st_uid = kauth_cred_geteuid(fp->f_cred);
st->st_gid = kauth_cred_getegid(fp->f_cred);
st->st_mode = S_IFCHR;

return 0;
}

static int
fops_pad_mmap(struct file *fp, off_t *offp, size_t len, int prot, int *flagsp,
int *advicep, struct uvm_object **uobjp, int *maxprotp)
{

return 1;
}

static int
fops_pad_read(struct file *fp, off_t *offp, struct uio *uio, kauth_cred_t cred,
int ioflag)
{
struct pad_softc *sc = fp->f_pad;

return pad_read(sc, offp, uio, cred, ioflag);
}

static int
pad_read(struct pad_softc *sc, off_t *offp, struct uio *uio, kauth_cred_t cred,
int ioflag)
{
pad_block_t pb;
int err, first;

err = 0;
first = 1;
DPRINTF("%s: resid=%zu\n", __func__, uio->uio_resid);
while (uio->uio_resid > 0) {
mutex_enter(&sc->sc_intr_lock);
err = pad_get_block(sc, &pb, MIN(uio->uio_resid, INT_MAX), first);
mutex_exit(&sc->sc_intr_lock);
first = 0;
if (err == EAGAIN) {
err = 0;
break;
}
if (err)
break;

DPRINTF("%s: move %d\n", __func__, pb.pb_len);
err = uiomove(pb.pb_ptr, pb.pb_len, uio);
if (err)
break;
}

return err;
}

static int
fops_pad_write(struct file *fp, off_t *offp, struct uio *uio, kauth_cred_t cred,
int ioflag)
{

return EOPNOTSUPP;
}

static int
pad_query_format(void *opaque, audio_format_query_t *afp)
{

return audio_query_format(pad_formats, PAD_NFORMATS, afp);
}

static int
pad_set_format(void *opaque, int setmode,
const audio_params_t *play, const audio_params_t *rec,
audio_filter_reg_t *pfil, audio_filter_reg_t *rfil)
{
struct pad_softc *sc = opaque;

KASSERT(mutex_owned(&sc->sc_lock));

/* XXX playback only */
pfil->codec = pad_swvol_codec;
pfil->context = sc;

return 0;
}

static int
pad_start_output(void *opaque, void *block, int blksize,
void (*intr)(void *), void *intrarg)
{
struct pad_softc *sc = opaque;
int err;
u_int framesize;
int ticks;

KASSERT(mutex_owned(&sc->sc_intr_lock));

sc->sc_intr = intr;
sc->sc_intrarg = intrarg;

DPRINTF("%s: blksize=%d\n", __func__, blksize);
err = pad_add_block(sc, block, blksize);
if (err) {
DPRINTF("%s: failed: %d\n", __func__, err);
/* "Silently" drop overflows, but keep pace */
err = 0;
}

framesize = PADCHAN * (PADPREC / NBBY) * PADFREQ;

sc->sc_resid += blksize;
ticks = mstohz(sc->sc_resid * 1000 / framesize);
sc->sc_resid -= hztoms(ticks) * framesize / 1000;

DPRINTF("%s: callout ms=%d\n", __func__, ms);
callout_schedule(&sc->sc_pcallout, ticks);

return err;
}

static int
pad_halt_output(void *opaque)
{
struct pad_softc *sc = opaque;

DPRINTF("%s\n", __func__);
KASSERT(mutex_owned(&sc->sc_intr_lock));

callout_halt(&sc->sc_pcallout, &sc->sc_intr_lock);

sc->sc_intr = NULL;
sc->sc_intrarg = NULL;
sc->sc_buflen = 0;
sc->sc_resid = 0;
sc->sc_rpos = sc->sc_wpos = 0;

return 0;
}

static void
pad_done_output(void *arg)
{
struct pad_softc *sc = arg;

DPRINTF("%s\n", __func__);

mutex_enter(&sc->sc_intr_lock);
(*sc->sc_intr)(sc->sc_intrarg);
mutex_exit(&sc->sc_intr_lock);
}

static int
pad_getdev(void *opaque, struct audio_device *ret)
{

strlcpy(ret->name, "Virtual Audio", sizeof(ret->name));
strlcpy(ret->version, osrelease, sizeof(ret->version));
strlcpy(ret->config, "pad", sizeof(ret->config));

return 0;
}

static int
pad_set_port(void *opaque, mixer_ctrl_t *mc)
{
struct pad_softc *sc = opaque;

KASSERT(mutex_owned(&sc->sc_lock));

switch (mc->dev) {
case PAD_OUTPUT_MASTER_VOLUME:
case PAD_INPUT_DAC_VOLUME:
if (mc->un.value.num_channels != 1)
return EINVAL;
sc->sc_swvol = mc->un.value.level[AUDIO_MIXER_LEVEL_MONO];
return 0;
}

return ENXIO;
}

static int
pad_get_port(void *opaque, mixer_ctrl_t *mc)
{
struct pad_softc *sc = opaque;

KASSERT(mutex_owned(&sc->sc_lock));

switch (mc->dev) {
case PAD_OUTPUT_MASTER_VOLUME:
case PAD_INPUT_DAC_VOLUME:
if (mc->un.value.num_channels != 1)
return EINVAL;
mc->un.value.level[AUDIO_MIXER_LEVEL_MONO] = sc->sc_swvol;
return 0;
}

return ENXIO;
}

static int
pad_query_devinfo(void *opaque, mixer_devinfo_t *di)
{
struct pad_softc *sc __diagused = opaque;

KASSERT(mutex_owned(&sc->sc_lock));

switch (di->index) {
case PAD_OUTPUT_CLASS:
di->mixer_class = PAD_OUTPUT_CLASS;
strcpy(di->label.name, AudioCoutputs);
di->type = AUDIO_MIXER_CLASS;
di->next = di->prev = AUDIO_MIXER_LAST;
return 0;
case PAD_INPUT_CLASS:
di->mixer_class = PAD_INPUT_CLASS;
strcpy(di->label.name, AudioCinputs);
di->type = AUDIO_MIXER_CLASS;
di->next = di->prev = AUDIO_MIXER_LAST;
return 0;
case PAD_OUTPUT_MASTER_VOLUME:
di->mixer_class = PAD_OUTPUT_CLASS;
strcpy(di->label.name, AudioNmaster);
di->type = AUDIO_MIXER_VALUE;
di->next = di->prev = AUDIO_MIXER_LAST;
di->un.v.num_channels = 1;
strcpy(di->un.v.units.name, AudioNvolume);
return 0;
case PAD_INPUT_DAC_VOLUME:
di->mixer_class = PAD_INPUT_CLASS;
strcpy(di->label.name, AudioNdac);
di->type = AUDIO_MIXER_VALUE;
di->next = di->prev = AUDIO_MIXER_LAST;
di->un.v.num_channels = 1;
strcpy(di->un.v.units.name, AudioNvolume);
return 0;
}

return ENXIO;
}

static int
pad_get_props(void *opaque)
{

return AUDIO_PROP_PLAYBACK;
}

static void
pad_get_locks(void *opaque, kmutex_t **intr, kmutex_t **thread)
{
struct pad_softc *sc = opaque;

*intr = &sc->sc_intr_lock;
*thread = &sc->sc_lock;
}

static void
pad_swvol_codec(audio_filter_arg_t *arg)
{
struct pad_softc *sc = arg->context;
const uint8_t *src;
uint8_t *dst;
u_int sample_count;
u_int i;
u_int bits;

src = arg->src;
dst = arg->dst;
sample_count = arg->count * arg->srcfmt->channels;
bits = arg->srcfmt->precision;

for (i = 0; i < sample_count; i++) {
int64_t v;

switch (howmany(bits, NBBY)) {
case 2: /* AUDIO_INTERNAL_BITS == 16 */
v = *(const int16_t *)src;
src += sizeof(int16_t);
break;
case 4: /* AUDIO_INTERNAL_BITS == 32 */
v = *(const int32_t *)src;
src += sizeof(int32_t);
break;
default:
v = 0;
break;
}

v = v * sc->sc_swvol / 255;

if (PADPREC > bits)
v = v << (PADPREC - bits);
else if (PADPREC < bits)
v = v >> (bits - PADPREC);

/* AUDIO_ENCODING_SLINEAR_LE */
#if PADPREC > 0
*dst++ = v;
#endif
#if PADPREC > 8
v >>= 8;
*dst++ = v;
#endif
#if PADPREC > 16
v >>= 8;
*dst++ = v;
#endif
#if PADPREC > 24
v >>= 8;
*dst++ = v;
#endif
}
}

MODULE(MODULE_CLASS_DRIVER, pad, "audio");

#ifdef _MODULE

#include "ioconf.c"

devmajor_t cmajor = NODEVMAJOR, bmajor = NODEVMAJOR;

/*
* We need our own version of cfattach since config(1)'s ioconf does not
* generate what we need
*/

static struct cfattach *pad_cfattachinit[] = { &pad_ca, NULL };

static struct cfattachinit pad_cfattach[] = {
{ "pad", pad_cfattachinit },
{ NULL, NULL }
};
#endif

static int
pad_modcmd(modcmd_t cmd, void *arg)
{
int error = 0;

switch (cmd) {
case MODULE_CMD_INIT:
#ifdef _MODULE
error = devsw_attach(pad_cd.cd_name, NULL, &bmajor,
&pad_cdevsw, &cmajor);
if (error)
break;

pad_cfattach[1] = cfattach_ioconf_pad[0];
error = config_init_component(cfdriver_ioconf_pad,
pad_cfattach, cfdata_ioconf_pad);
if (error) {
devsw_detach(NULL, &pad_cdevsw);
break;
}
#endif
break;

case MODULE_CMD_FINI:
#ifdef _MODULE
error = config_fini_component(cfdriver_ioconf_pad,
pad_cfattach, cfdata_ioconf_pad);
if (error == 0)
devsw_detach(NULL, &pad_cdevsw);
#endif
break;

default:
error = ENOTTY;
}

return error;
}