Commit 8fdff6a3 authored by Daniel Mack's avatar Daniel Mack Committed by Takashi Iwai
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ALSA: snd-usb: implement new endpoint streaming model



This patch adds a new generic streaming logic for audio over USB.

It defines a model (snd_usb_endpoint) that handles everything that
is related to an USB endpoint and its streaming. There are functions to
activate and deactivate an endpoint (which call usb_set_interface()),
and to start and stop its URBs. It also has function pointers to be
called when data was received or is about to be sent, and pointer to
a sync slave (another snd_usb_endpoint) that is informed when data has
been received.

A snd_usb_endpoint knows about its state and implements a refcounting,
so only the first user will actually start the URBs and only the last
one to stop it will tear them down again.

With this sort of abstraction, the actual streaming is decoupled from
the pcm handling, which makes the "implicit feedback" mechanisms easy to
implement.

In order to split changes properly, this patch only adds the new
implementation but leaves the old one around, so the the driver doesn't
change its behaviour. The switch to actually use the new code is
submitted separately.

Signed-off-by: default avatarDaniel Mack <zonque@gmail.com>
Signed-off-by: default avatarTakashi Iwai <tiwai@suse.de>
parent 596580d0
......@@ -30,13 +30,17 @@ struct audioformat {
};
struct snd_usb_substream;
struct snd_usb_endpoint;
struct snd_urb_ctx {
struct urb *urb;
unsigned int buffer_size; /* size of data buffer, if data URB */
struct snd_usb_substream *subs;
struct snd_usb_endpoint *ep;
int index; /* index for urb array */
int packets; /* number of packets per urb */
int packet_size[MAX_PACKS_HS]; /* size of packets for next submission */
struct list_head ready_list;
};
struct snd_urb_ops {
......@@ -46,6 +50,60 @@ struct snd_urb_ops {
int (*retire_sync)(struct snd_usb_substream *subs, struct snd_pcm_runtime *runtime, struct urb *u);
};
struct snd_usb_endpoint {
struct snd_usb_audio *chip;
int use_count;
int ep_num; /* the referenced endpoint number */
int type; /* SND_USB_ENDPOINT_TYPE_* */
unsigned long flags;
void (*prepare_data_urb) (struct snd_usb_substream *subs,
struct urb *urb);
void (*retire_data_urb) (struct snd_usb_substream *subs,
struct urb *urb);
struct snd_usb_substream *data_subs;
struct snd_usb_endpoint *sync_master;
struct snd_usb_endpoint *sync_slave;
struct snd_urb_ctx urb[MAX_URBS];
struct snd_usb_packet_info {
uint32_t packet_size[MAX_PACKS_HS];
int packets;
} next_packet[MAX_URBS];
int next_packet_read_pos, next_packet_write_pos;
struct list_head ready_playback_urbs;
unsigned int nurbs; /* # urbs */
unsigned long active_mask; /* bitmask of active urbs */
unsigned long unlink_mask; /* bitmask of unlinked urbs */
char *syncbuf; /* sync buffer for all sync URBs */
dma_addr_t sync_dma; /* DMA address of syncbuf */
unsigned int pipe; /* the data i/o pipe */
unsigned int freqn; /* nominal sampling rate in fs/fps in Q16.16 format */
unsigned int freqm; /* momentary sampling rate in fs/fps in Q16.16 format */
int freqshift; /* how much to shift the feedback value to get Q16.16 */
unsigned int freqmax; /* maximum sampling rate, used for buffer management */
unsigned int phase; /* phase accumulator */
unsigned int maxpacksize; /* max packet size in bytes */
unsigned int maxframesize; /* max packet size in frames */
unsigned int curpacksize; /* current packet size in bytes (for capture) */
unsigned int curframesize; /* current packet size in frames (for capture) */
unsigned int syncmaxsize; /* sync endpoint packet size */
unsigned int fill_max:1; /* fill max packet size always */
unsigned int datainterval; /* log_2 of data packet interval */
unsigned int syncinterval; /* P for adaptive mode, 0 otherwise */
unsigned char silence_value;
unsigned int stride;
int iface, alt_idx;
spinlock_t lock;
struct list_head list;
};
struct snd_usb_substream {
struct snd_usb_stream *stream;
struct usb_device *dev;
......
......@@ -20,9 +20,11 @@
#include <linux/ratelimit.h>
#include <linux/usb.h>
#include <linux/usb/audio.h>
#include <linux/slab.h>
#include <sound/core.h>
#include <sound/pcm.h>
#include <sound/pcm_params.h>
#include "usbaudio.h"
#include "helper.h"
......@@ -30,6 +32,9 @@
#include "endpoint.h"
#include "pcm.h"
#define EP_FLAG_ACTIVATED 0
#define EP_FLAG_RUNNING 1
/*
* convert a sampling rate into our full speed format (fs/1000 in Q16.16)
* this will overflow at approx 524 kHz
......@@ -51,7 +56,7 @@ static inline unsigned get_usb_high_speed_rate(unsigned int rate)
/*
* unlink active urbs.
*/
static int deactivate_urbs(struct snd_usb_substream *subs, int force, int can_sleep)
static int deactivate_urbs_old(struct snd_usb_substream *subs, int force, int can_sleep)
{
struct snd_usb_audio *chip = subs->stream->chip;
unsigned int i;
......@@ -113,7 +118,7 @@ static void release_urb_ctx(struct snd_urb_ctx *u)
/*
* wait until all urbs are processed.
*/
static int wait_clear_urbs(struct snd_usb_substream *subs)
static int wait_clear_urbs_old(struct snd_usb_substream *subs)
{
unsigned long end_time = jiffies + msecs_to_jiffies(1000);
unsigned int i;
......@@ -148,8 +153,8 @@ void snd_usb_release_substream_urbs(struct snd_usb_substream *subs, int force)
int i;
/* stop urbs (to be sure) */
deactivate_urbs(subs, force, 1);
wait_clear_urbs(subs);
deactivate_urbs_old(subs, force, 1);
wait_clear_urbs_old(subs);
for (i = 0; i < MAX_URBS; i++)
release_urb_ctx(&subs->dataurb[i]);
......@@ -164,7 +169,7 @@ void snd_usb_release_substream_urbs(struct snd_usb_substream *subs, int force)
/*
* complete callback from data urb
*/
static void snd_complete_urb(struct urb *urb)
static void snd_complete_urb_old(struct urb *urb)
{
struct snd_urb_ctx *ctx = urb->context;
struct snd_usb_substream *subs = ctx->subs;
......@@ -318,7 +323,7 @@ int snd_usb_init_substream_urbs(struct snd_usb_substream *subs,
u->urb->transfer_flags = URB_ISO_ASAP | URB_NO_TRANSFER_DMA_MAP;
u->urb->interval = 1 << subs->datainterval;
u->urb->context = u;
u->urb->complete = snd_complete_urb;
u->urb->complete = snd_complete_urb_old;
}
if (subs->syncpipe) {
......@@ -856,7 +861,7 @@ static int start_urbs(struct snd_usb_substream *subs, struct snd_pcm_runtime *ru
__error:
// snd_pcm_stop(subs->pcm_substream, SNDRV_PCM_STATE_XRUN);
deactivate_urbs(subs, 0, 0);
deactivate_urbs_old(subs, 0, 0);
return -EPIPE;
}
......@@ -917,7 +922,7 @@ int snd_usb_substream_playback_trigger(struct snd_pcm_substream *substream, int
subs->ops.prepare = prepare_playback_urb;
return 0;
case SNDRV_PCM_TRIGGER_STOP:
return deactivate_urbs(subs, 0, 0);
return deactivate_urbs_old(subs, 0, 0);
case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
subs->ops.prepare = prepare_nodata_playback_urb;
return 0;
......@@ -935,7 +940,7 @@ int snd_usb_substream_capture_trigger(struct snd_pcm_substream *substream, int c
subs->ops.retire = retire_capture_urb;
return start_urbs(subs, substream->runtime);
case SNDRV_PCM_TRIGGER_STOP:
return deactivate_urbs(subs, 0, 0);
return deactivate_urbs_old(subs, 0, 0);
case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
subs->ops.retire = retire_paused_capture_urb;
return 0;
......@@ -951,8 +956,8 @@ int snd_usb_substream_prepare(struct snd_usb_substream *subs,
struct snd_pcm_runtime *runtime)
{
/* clear urbs (to be sure) */
deactivate_urbs(subs, 0, 1);
wait_clear_urbs(subs);
deactivate_urbs_old(subs, 0, 1);
wait_clear_urbs_old(subs);
/* for playback, submit the URBs now; otherwise, the first hwptr_done
* updates for all URBs would happen at the same time when starting */
......@@ -964,3 +969,904 @@ int snd_usb_substream_prepare(struct snd_usb_substream *subs,
return 0;
}
int snd_usb_endpoint_implict_feedback_sink(struct snd_usb_endpoint *ep)
{
return ep->sync_master &&
ep->sync_master->type == SND_USB_ENDPOINT_TYPE_DATA &&
ep->type == SND_USB_ENDPOINT_TYPE_DATA &&
usb_pipeout(ep->pipe);
}
/* determine the number of frames in the next packet */
static int next_packet_size(struct snd_usb_endpoint *ep)
{
unsigned long flags;
int ret;
if (ep->fill_max)
return ep->maxframesize;
spin_lock_irqsave(&ep->lock, flags);
ep->phase = (ep->phase & 0xffff)
+ (ep->freqm << ep->datainterval);
ret = min(ep->phase >> 16, ep->maxframesize);
spin_unlock_irqrestore(&ep->lock, flags);
return ret;
}
static void retire_outbound_urb(struct snd_usb_endpoint *ep,
struct snd_urb_ctx *urb_ctx)
{
if (ep->retire_data_urb)
ep->retire_data_urb(ep->data_subs, urb_ctx->urb);
}
static void retire_inbound_urb(struct snd_usb_endpoint *ep,
struct snd_urb_ctx *urb_ctx)
{
struct urb *urb = urb_ctx->urb;
if (ep->sync_slave)
snd_usb_handle_sync_urb(ep->sync_slave, ep, urb);
if (ep->retire_data_urb)
ep->retire_data_urb(ep->data_subs, urb);
}
static void prepare_outbound_urb_sizes(struct snd_usb_endpoint *ep,
struct snd_urb_ctx *ctx)
{
int i;
for (i = 0; i < ctx->packets; ++i)
ctx->packet_size[i] = next_packet_size(ep);
}
/*
* Prepare a PLAYBACK urb for submission to the bus.
*/
static void prepare_outbound_urb(struct snd_usb_endpoint *ep,
struct snd_urb_ctx *ctx)
{
int i;
struct urb *urb = ctx->urb;
unsigned char *cp = urb->transfer_buffer;
urb->dev = ep->chip->dev; /* we need to set this at each time */
switch (ep->type) {
case SND_USB_ENDPOINT_TYPE_DATA:
if (ep->prepare_data_urb) {
ep->prepare_data_urb(ep->data_subs, urb);
} else {
/* no data provider, so send silence */
unsigned int offs = 0;
for (i = 0; i < ctx->packets; ++i) {
int counts = ctx->packet_size[i];
urb->iso_frame_desc[i].offset = offs * ep->stride;
urb->iso_frame_desc[i].length = counts * ep->stride;
offs += counts;
}
urb->number_of_packets = ctx->packets;
urb->transfer_buffer_length = offs * ep->stride;
memset(urb->transfer_buffer, ep->silence_value,
offs * ep->stride);
}
break;
case SND_USB_ENDPOINT_TYPE_SYNC:
if (snd_usb_get_speed(ep->chip->dev) >= USB_SPEED_HIGH) {
/*
* fill the length and offset of each urb descriptor.
* the fixed 12.13 frequency is passed as 16.16 through the pipe.
*/
urb->iso_frame_desc[0].length = 4;
urb->iso_frame_desc[0].offset = 0;
cp[0] = ep->freqn;
cp[1] = ep->freqn >> 8;
cp[2] = ep->freqn >> 16;
cp[3] = ep->freqn >> 24;
} else {
/*
* fill the length and offset of each urb descriptor.
* the fixed 10.14 frequency is passed through the pipe.
*/
urb->iso_frame_desc[0].length = 3;
urb->iso_frame_desc[0].offset = 0;
cp[0] = ep->freqn >> 2;
cp[1] = ep->freqn >> 10;
cp[2] = ep->freqn >> 18;
}
break;
}
}
/*
* Prepare a CAPTURE or SYNC urb for submission to the bus.
*/
static inline void prepare_inbound_urb(struct snd_usb_endpoint *ep,
struct snd_urb_ctx *urb_ctx)
{
int i, offs;
struct urb *urb = urb_ctx->urb;
urb->dev = ep->chip->dev; /* we need to set this at each time */
switch (ep->type) {
case SND_USB_ENDPOINT_TYPE_DATA:
offs = 0;
for (i = 0; i < urb_ctx->packets; i++) {
urb->iso_frame_desc[i].offset = offs;
urb->iso_frame_desc[i].length = ep->curpacksize;
offs += ep->curpacksize;
}
urb->transfer_buffer_length = offs;
urb->number_of_packets = urb_ctx->packets;
break;
case SND_USB_ENDPOINT_TYPE_SYNC:
urb->iso_frame_desc[0].length = min(4u, ep->syncmaxsize);
urb->iso_frame_desc[0].offset = 0;
break;
}
}
static void queue_pending_output_urbs(struct snd_usb_endpoint *ep)
{
while (test_bit(EP_FLAG_RUNNING, &ep->flags)) {
unsigned long flags;
struct snd_usb_packet_info *packet;
struct snd_urb_ctx *ctx = NULL;
struct urb *urb;
int err, i;
spin_lock_irqsave(&ep->lock, flags);
if (ep->next_packet_read_pos != ep->next_packet_write_pos) {
packet = ep->next_packet + ep->next_packet_read_pos;
ep->next_packet_read_pos++;
ep->next_packet_read_pos %= MAX_URBS;
/* take URB out of FIFO */
if (!list_empty(&ep->ready_playback_urbs))
ctx = list_first_entry(&ep->ready_playback_urbs,
struct snd_urb_ctx, ready_list);
}
spin_unlock_irqrestore(&ep->lock, flags);
if (ctx == NULL)
return;
list_del_init(&ctx->ready_list);
urb = ctx->urb;
/* copy over the length information */
for (i = 0; i < packet->packets; i++)
ctx->packet_size[i] = packet->packet_size[i];
prepare_outbound_urb(ep, ctx);
err = usb_submit_urb(ctx->urb, GFP_ATOMIC);
if (err < 0)
snd_printk(KERN_ERR "Unable to submit urb #%d: %d (urb %p)\n",
ctx->index, err, ctx->urb);
else
set_bit(ctx->index, &ep->active_mask);
}
}
/*
* complete callback for urbs
*/
static void snd_complete_urb(struct urb *urb)
{
struct snd_urb_ctx *ctx = urb->context;
struct snd_usb_endpoint *ep = ctx->ep;
int err;
if (unlikely(urb->status == -ENOENT || /* unlinked */
urb->status == -ENODEV || /* device removed */
urb->status == -ECONNRESET || /* unlinked */
urb->status == -ESHUTDOWN || /* device disabled */
ep->chip->shutdown)) /* device disconnected */
goto exit_clear;
if (usb_pipeout(ep->pipe)) {
retire_outbound_urb(ep, ctx);
/* can be stopped during retire callback */
if (unlikely(!test_bit(EP_FLAG_RUNNING, &ep->flags)))
goto exit_clear;
if (snd_usb_endpoint_implict_feedback_sink(ep)) {
unsigned long flags;
spin_lock_irqsave(&ep->lock, flags);
list_add_tail(&ctx->ready_list, &ep->ready_playback_urbs);
spin_unlock_irqrestore(&ep->lock, flags);
queue_pending_output_urbs(ep);
goto exit_clear;
}
prepare_outbound_urb_sizes(ep, ctx);
prepare_outbound_urb(ep, ctx);
} else {
retire_inbound_urb(ep, ctx);
/* can be stopped during retire callback */
if (unlikely(!test_bit(EP_FLAG_RUNNING, &ep->flags)))
goto exit_clear;
prepare_inbound_urb(ep, ctx);
}
err = usb_submit_urb(urb, GFP_ATOMIC);
if (err == 0)
return;
snd_printk(KERN_ERR "cannot submit urb (err = %d)\n", err);
//snd_pcm_stop(substream, SNDRV_PCM_STATE_XRUN);
exit_clear:
clear_bit(ctx->index, &ep->active_mask);
}
struct snd_usb_endpoint *snd_usb_add_endpoint(struct snd_usb_audio *chip,
struct usb_host_interface *alts,
int ep_num, int direction, int type)
{
struct list_head *p;
struct snd_usb_endpoint *ep;
int ret, is_playback = direction == SNDRV_PCM_STREAM_PLAYBACK;
mutex_lock(&chip->mutex);
list_for_each(p, &chip->ep_list) {
ep = list_entry(p, struct snd_usb_endpoint, list);
if (ep->ep_num == ep_num &&
ep->iface == alts->desc.bInterfaceNumber &&
ep->alt_idx == alts->desc.bAlternateSetting) {
snd_printdd(KERN_DEBUG "Re-using EP %x in iface %d,%d @%p\n",
ep_num, ep->iface, ep->alt_idx, ep);
goto __exit_unlock;
}
}
snd_printdd(KERN_DEBUG "Creating new %s %s endpoint #%x\n",
is_playback ? "playback" : "capture",
type == SND_USB_ENDPOINT_TYPE_DATA ? "data" : "sync",
ep_num);
/* select the alt setting once so the endpoints become valid */
ret = usb_set_interface(chip->dev, alts->desc.bInterfaceNumber,
alts->desc.bAlternateSetting);
if (ret < 0) {
snd_printk(KERN_ERR "%s(): usb_set_interface() failed, ret = %d\n",
__func__, ret);
ep = NULL;
goto __exit_unlock;
}
ep = kzalloc(sizeof(*ep), GFP_KERNEL);
if (!ep)
goto __exit_unlock;
ep->chip = chip;
spin_lock_init(&ep->lock);
ep->type = type;
ep->ep_num = ep_num;
ep->iface = alts->desc.bInterfaceNumber;
ep->alt_idx = alts->desc.bAlternateSetting;
INIT_LIST_HEAD(&ep->ready_playback_urbs);
ep_num &= USB_ENDPOINT_NUMBER_MASK;
if (is_playback)
ep->pipe = usb_sndisocpipe(chip->dev, ep_num);
else
ep->pipe = usb_rcvisocpipe(chip->dev, ep_num);
if (type == SND_USB_ENDPOINT_TYPE_SYNC) {
if (get_endpoint(alts, 1)->bLength >= USB_DT_ENDPOINT_AUDIO_SIZE &&
get_endpoint(alts, 1)->bRefresh >= 1 &&
get_endpoint(alts, 1)->bRefresh <= 9)
ep->syncinterval = get_endpoint(alts, 1)->bRefresh;
else if (snd_usb_get_speed(chip->dev) == USB_SPEED_FULL)
ep->syncinterval = 1;
else if (get_endpoint(alts, 1)->bInterval >= 1 &&
get_endpoint(alts, 1)->bInterval <= 16)
ep->syncinterval = get_endpoint(alts, 1)->bInterval - 1;
else
ep->syncinterval = 3;
ep->syncmaxsize = le16_to_cpu(get_endpoint(alts, 1)->wMaxPacketSize);
}
list_add_tail(&ep->list, &chip->ep_list);
__exit_unlock:
mutex_unlock(&chip->mutex);
return ep;
}
/*
* wait until all urbs are processed.
*/
static int wait_clear_urbs(struct snd_usb_endpoint *ep)
{
unsigned long end_time = jiffies + msecs_to_jiffies(1000);
unsigned int i;
int alive;
do {
alive = 0;
for (i = 0; i < ep->nurbs; i++)
if (test_bit(i, &ep->active_mask))
alive++;
if (!alive)
break;
schedule_timeout_uninterruptible(1);
} while (time_before(jiffies, end_time));
if (alive)
snd_printk(KERN_ERR "timeout: still %d active urbs on EP #%x\n",
alive, ep->ep_num);
return 0;
}
/*
* unlink active urbs.
*/
static int deactivate_urbs(struct snd_usb_endpoint *ep, int force, int can_sleep)
{
unsigned long flags;
unsigned int i;
int async;
if (!force && ep->chip->shutdown) /* to be sure... */
return -EBADFD;
async = !can_sleep && ep->chip->async_unlink;
clear_bit(EP_FLAG_RUNNING, &ep->flags);
INIT_LIST_HEAD(&ep->ready_playback_urbs);
ep->next_packet_read_pos = 0;
ep->next_packet_write_pos = 0;
if (!async && in_interrupt())
return 0;
for (i = 0; i < ep->nurbs; i++) {
if (test_bit(i, &ep->active_mask)) {
if (!test_and_set_bit(i, &ep->unlink_mask)) {
struct urb *u = ep->urb[i].urb;
if (async)
usb_unlink_urb(u);
else
usb_kill_urb(u);
}
}
}
return 0;
}
/*
* release an endpoint's urbs
*/
static void release_urbs(struct snd_usb_endpoint *ep, int force)
{
int i;
/* route incoming urbs to nirvana */
ep->retire_data_urb = NULL;
ep->prepare_data_urb = NULL;
/* stop urbs */
deactivate_urbs(ep, force, 1);
wait_clear_urbs(ep);
for (i = 0; i < ep->nurbs; i++)
release_urb_ctx(&ep->urb[i]);
if (ep->syncbuf)
usb_free_coherent(ep->chip->dev, SYNC_URBS * 4,
ep->syncbuf, ep->sync_dma);
ep->syncbuf = NULL;
ep->nurbs = 0;
}
static int data_ep_set_params(struct snd_usb_endpoint *ep,
struct snd_pcm_hw_params *hw_params,
struct audioformat *fmt,
struct snd_usb_endpoint *sync_ep)
{
unsigned int maxsize, i, urb_packs, total_packs, packs_per_ms;
int period_bytes = params_period_bytes(hw_params);
int format = params_format(hw_params);
int is_playback = usb_pipeout(ep->pipe);
int frame_bits = snd_pcm_format_physical_width(params_format(hw_params)) *
params_channels(hw_params);
ep->datainterval = fmt->datainterval;
ep->stride = frame_bits >> 3;
ep->silence_value = format == SNDRV_PCM_FORMAT_U8 ? 0x80 : 0;
/* calculate max. frequency */