rockbox/firmware/usbstack/usb_audio.c
Dana Conrad a1837d2d80 usbaudio: block playback while usbaudio is active
Needed due to us commandeering the AUDIO DSP "channel" for USBAudio.
If/When we add another DSP channel, this can be reverted.

Works, but still goes to a "blank" WPS screen for a split second before
cancelling out.

Change-Id: I5fb8a1e226b4d3e46c86c59d593d807f49d7a35f
2025-11-15 07:38:46 -05:00

1443 lines
47 KiB
C

/***************************************************************************
* __________ __ ___.
* Open \______ \ ____ ____ | | _\_ |__ _______ ___
* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
* \/ \/ \/ \/ \/
* $Id: $
*
* Copyright (C) 2010 by Amaury Pouly
*
* All files in this archive are subject to the GNU General Public License.
* See the file COPYING in the source tree root for full license agreement.
*
* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
* KIND, either express or implied.
*
****************************************************************************/
/* NOTE
*
* This is USBAudio 1.0. USBAudio 2.0 is notably _not backwards compatible!_
* USBAudio 1.0 over _USB_ 2.0 is perfectly valid!
*
* Relevant specifications are USB 2.0 and USB Audio Class 1.0.
*/
#include "string.h"
#include "system.h"
#include "usb_core.h"
#include "usb_drv.h"
#include "kernel.h"
#include "sound.h"
#include "usb_class_driver.h"
#include "usb_audio_def.h"
#include "pcm_sampr.h"
#include "audio.h"
#include "sound.h"
#include "stdlib.h"
#include "fixedpoint.h"
#include "misc.h"
#include "settings.h"
#include "core_alloc.h"
#include "pcm_mixer.h"
#include "dsp_core.h"
#define LOGF_ENABLE
#include "logf.h"
// is there a "best practices" for converting between floats and fixed point?
// NOTE: SIGNED
#define TO_16DOT16_FIXEDPT(val) ((int32_t)(val) * (1<<16))
#define TO_DOUBLE(val) ((double)(val) / (1<<16))
/* Audio Control Interface */
static struct usb_interface_descriptor
ac_interface =
{
.bLength = sizeof(struct usb_interface_descriptor),
.bDescriptorType = USB_DT_INTERFACE,
.bInterfaceNumber = 0,
.bAlternateSetting = 0,
.bNumEndpoints = 0,
.bInterfaceClass = USB_CLASS_AUDIO,
.bInterfaceSubClass = USB_SUBCLASS_AUDIO_CONTROL,
.bInterfaceProtocol = 0,
.iInterface = 0
};
/* Audio Control Terminals/Units*/
static struct usb_ac_header ac_header =
{
.bLength = USB_AC_SIZEOF_HEADER(1), /* one interface */
.bDescriptorType = USB_DT_CS_INTERFACE,
.bDescriptorSubType = USB_AC_HEADER,
.bcdADC = 0x0100, /* Identifies this as usb audio class 1.0 */
.wTotalLength = 0, /* fill later */
.bInCollection = 1, /* one interface */
.baInterfaceNr = {0}, /* fill later */
};
enum
{
AC_PLAYBACK_INPUT_TERMINAL_ID = 1,
AC_PLAYBACK_FEATURE_ID,
AC_PLAYBACK_OUTPUT_TERMINAL_ID,
};
static struct usb_ac_input_terminal ac_playback_input =
{
.bLength = sizeof(struct usb_ac_input_terminal),
.bDescriptorType = USB_DT_CS_INTERFACE,
.bDescriptorSubType = USB_AC_INPUT_TERMINAL,
.bTerminalId = AC_PLAYBACK_INPUT_TERMINAL_ID,
.wTerminalType = USB_AC_TERMINAL_STREAMING,
.bAssocTerminal = 0,
.bNrChannels = 2,
.wChannelConfig = USB_AC_CHANNELS_LEFT_RIGHT_FRONT,
.iChannelNames = 0,
.iTerminal = 0,
};
static struct usb_ac_output_terminal ac_playback_output =
{
.bLength = sizeof(struct usb_ac_output_terminal),
.bDescriptorType = USB_DT_CS_INTERFACE,
.bDescriptorSubType = USB_AC_OUTPUT_TERMINAL,
.bTerminalId = AC_PLAYBACK_OUTPUT_TERMINAL_ID,
.wTerminalType = USB_AC_OUTPUT_TERMINAL_HEADPHONES,
.bAssocTerminal = 0,
.bSourceId = AC_PLAYBACK_FEATURE_ID,
.iTerminal = 0,
};
/* Feature Unit with 2 logical channels and 1 byte(8 bits) per control */
DEFINE_USB_AC_FEATURE_UNIT(8, 2)
static struct usb_ac_feature_unit_8_2 ac_playback_feature =
{
.bLength = sizeof(struct usb_ac_feature_unit_8_2),
.bDescriptorType = USB_DT_CS_INTERFACE,
.bDescriptorSubType = USB_AC_FEATURE_UNIT,
.bUnitId = AC_PLAYBACK_FEATURE_ID,
.bSourceId = AC_PLAYBACK_INPUT_TERMINAL_ID,
.bControlSize = 1, /* by definition */
.bmaControls = {
[0] = USB_AC_FU_MUTE | USB_AC_FU_VOLUME,
[1] = 0,
[2] = 0
},
.iFeature = 0
};
/* Audio Streaming Interface */
/* Alternative: no streaming */
static struct usb_interface_descriptor
as_interface_alt_idle_playback =
{
.bLength = sizeof(struct usb_interface_descriptor),
.bDescriptorType = USB_DT_INTERFACE,
.bInterfaceNumber = 0,
.bAlternateSetting = 0,
.bNumEndpoints = 0,
.bInterfaceClass = USB_CLASS_AUDIO,
.bInterfaceSubClass = USB_SUBCLASS_AUDIO_STREAMING,
.bInterfaceProtocol = 0,
.iInterface = 0
};
/* Alternative: output streaming */
static struct usb_interface_descriptor
as_interface_alt_playback =
{
.bLength = sizeof(struct usb_interface_descriptor),
.bDescriptorType = USB_DT_INTERFACE,
.bInterfaceNumber = 0,
.bAlternateSetting = 1,
.bNumEndpoints = 2, // iso audio, iso feedback
.bInterfaceClass = USB_CLASS_AUDIO,
.bInterfaceSubClass = USB_SUBCLASS_AUDIO_STREAMING,
.bInterfaceProtocol = 0,
.iInterface = 0
};
/* Class Specific Audio Streaming Interface */
static struct usb_as_interface
as_playback_cs_interface =
{
.bLength = sizeof(struct usb_as_interface),
.bDescriptorType = USB_DT_CS_INTERFACE,
.bDescriptorSubType = USB_AS_GENERAL,
.bTerminalLink = AC_PLAYBACK_INPUT_TERMINAL_ID,
.bDelay = 1,
.wFormatTag = USB_AS_FORMAT_TYPE_I_PCM
};
static struct usb_as_format_type_i_discrete
as_playback_format_type_i =
{
.bLength = USB_AS_SIZEOF_FORMAT_TYPE_I_DISCRETE((HW_FREQ_44+1)),
.bDescriptorType = USB_DT_CS_INTERFACE,
.bDescriptorSubType = USB_AS_FORMAT_TYPE,
.bFormatType = USB_AS_FORMAT_TYPE_I,
.bNrChannels = 2, /* Stereo */
.bSubframeSize = 2, /* 2 bytes per sample */
.bBitResolution = 16, /* all 16-bits are used */
.bSamFreqType = (HW_FREQ_44+1),
.tSamFreq = {
// only values 44.1k and higher (array is in descending order)
[0 ... HW_FREQ_44 ] = {0}, /* filled later */
}
};
static struct usb_as_iso_audio_endpoint
as_iso_audio_out_ep =
{
.bLength = sizeof(struct usb_as_iso_audio_endpoint),
.bDescriptorType = USB_DT_ENDPOINT,
.bEndpointAddress = USB_DIR_OUT, /* filled later */
.bmAttributes = USB_ENDPOINT_XFER_ISOC | USB_ENDPOINT_SYNC_ASYNC | USB_ENDPOINT_USAGE_DATA,
.wMaxPacketSize = 0, /* filled later */
.bInterval = 0, /* filled later - 1 for full speed, 4 for high-speed */
.bRefresh = 0,
.bSynchAddress = 0 /* filled later to the address of as_iso_synch_in_ep */
};
/*
* Updaing the desired sample frequency:
*
* The iso OUT ep is inextricably linked to the feedback iso IN ep
* when using Asynchronous mode. It periodically describes to the host
* how fast to send the data.
*
* Some notes from the usbaudio 1.0 documentation:
* - bSyncAddress of the iso OUT ep must be set to the address of the iso IN feedback ep
* - bSyncAddress of the iso IN feedback ep must be zero
* - F_f (desired sampling frequency) describes directly the number of samples the endpoint
* wants to receive per frame to match the actual sampling frequency F_s
* - There is a value, (2^(10-P)), which is how often (in 1mS frames) the F_f value will be sent
* - P appears to be somewhat arbitrary, though the spec wants it to relate the real sample rate
* F_s to the master clock rate F_m by the relationship (F_m = F_s * (2^(P-1)))
* - The above description of P is somewhat moot because of how much buffering we have. I suspect it
* was written for devices with essentially zero buffering.
* - bRefresh of the feedback endpoint descriptor should be set to (10-P). This can range from 1 to 9.
* A value of 1 would mean refreshing every 2^1 mS = 2 mS, a value of 9 would mean refreshing every
* 2^9 mS = 512 mS.
* - The F_f value should be encoded in "10.10" format, but justified to the leftmost 24 bits,
* so it ends up looking like "10.14" format. This format is 3 bytes long. On USB 2.0, it seems that
* the USB spec overrides the UAC 1.0 spec here, so high-speed bus operation needs "16.16" format,
* in a 4 byte packet.
*/
#define FEEDBACK_UPDATE_RATE_P 5
#define FEEDBACK_UPDATE_RATE_REFRESH (10-FEEDBACK_UPDATE_RATE_P)
#define FEEDBACK_UPDATE_RATE_FRAMES (0x1<<FEEDBACK_UPDATE_RATE_REFRESH)
static struct usb_as_iso_synch_endpoint
as_iso_synch_in_ep =
{
.bLength = sizeof(struct usb_as_iso_synch_endpoint),
.bDescriptorType = USB_DT_ENDPOINT,
.bEndpointAddress = USB_DIR_IN, /* filled later */
.bmAttributes = USB_ENDPOINT_XFER_ISOC | USB_ENDPOINT_SYNC_NONE | USB_ENDPOINT_USAGE_FEEDBACK,
.wMaxPacketSize = 4,
.bInterval = 0, /* filled later - 1 or 4 depending on bus speed */
.bRefresh = FEEDBACK_UPDATE_RATE_REFRESH, /* This describes how often this ep will update F_f (see above) */
.bSynchAddress = 0 /* MUST be zero! */
};
static struct usb_as_iso_ctrldata_endpoint
as_iso_ctrldata_samfreq =
{
.bLength = sizeof(struct usb_as_iso_ctrldata_endpoint),
.bDescriptorType = USB_DT_CS_ENDPOINT,
.bDescriptorSubType = USB_AS_EP_GENERAL,
.bmAttributes = USB_AS_EP_CS_SAMPLING_FREQ_CTL,
.bLockDelayUnits = 0, /* undefined */
.wLockDelay = 0 /* undefined */
};
static const struct usb_descriptor_header* const ac_cs_descriptors_list[] =
{
(struct usb_descriptor_header *) &ac_header,
(struct usb_descriptor_header *) &ac_playback_input,
(struct usb_descriptor_header *) &ac_playback_feature,
(struct usb_descriptor_header *) &ac_playback_output,
};
#define AC_CS_DESCRIPTORS_LIST_SIZE (sizeof(ac_cs_descriptors_list)/sizeof(ac_cs_descriptors_list[0]))
// TODO: AudioControl Interrupt endpoint to inform the host that changes were made on-device!
// The most immediately useful of this capability is volume and mute changes.
static const struct usb_descriptor_header* const usb_descriptors_list[] =
{
/* Audio Control */
(struct usb_descriptor_header *) &ac_interface,
(struct usb_descriptor_header *) &ac_header,
(struct usb_descriptor_header *) &ac_playback_input,
(struct usb_descriptor_header *) &ac_playback_feature,
(struct usb_descriptor_header *) &ac_playback_output,
/* Audio Streaming */
/* Idle Playback */
(struct usb_descriptor_header *) &as_interface_alt_idle_playback,
/* Playback */
(struct usb_descriptor_header *) &as_interface_alt_playback,
(struct usb_descriptor_header *) &as_playback_cs_interface,
(struct usb_descriptor_header *) &as_playback_format_type_i,
/* NOTE: the order of these three is important for maximum compatibility.
* Synch ep should follow iso out ep, with ctrldata descriptor coming first. */
(struct usb_descriptor_header *) &as_iso_ctrldata_samfreq,
(struct usb_descriptor_header *) &as_iso_audio_out_ep,
(struct usb_descriptor_header *) &as_iso_synch_in_ep,
};
#define USB_DESCRIPTORS_LIST_SIZE (sizeof(usb_descriptors_list)/sizeof(usb_descriptors_list[0]))
static int usb_interface; /* first interface */
static int usb_as_playback_intf_alt; /* playback streaming interface alternate setting */
static int as_playback_freq_idx; /* audio playback streaming frequency index (in hw_freq_sampr) */
static int out_iso_ep_adr; /* output isochronous endpoint */
static int in_iso_feedback_ep_adr; /* input feedback isochronous endpoint */
/* small buffer used for control transfers */
static unsigned char usb_buffer[128] USB_DEVBSS_ATTR;
/* number of buffers: 2 is double-buffering (one for usb, one for playback),
* 3 is triple-buffering (one for usb, one for playback, one for queuing), ... */
/* Samples come in (maximum) 1023 byte chunks. Samples are also 16 bits per channel per sample.
*
* One buffer holds (1023 / (2Bx2ch)) = 255 (rounded down) samples
* So the _maximum_ play time per buffer is (255 / sps).
* For 44100 Hz: 5.7 mS
* For 48000 Hz: 5.3 mS
* For 192000 Hz: 1.3 mS
*
* From testing on MacOS (likely to be the toughest customer...) on Designware driver
* we get data every Frame (so, every millisecond).
*
* If we get data every millisecond, we need 1mS to transfer 1.3mS of playback
* in order to sustain 192 kHz playback!
* At 44.1 kHz, the requirements are much less - 1mS of data transfer for 5.7mS of playback
* At 48 kHz, 1mS can transfer 5.3mS of playback.
*
* It appears that this is "maximum", but we more likely get "enough for 1mS" every millisecond.
*
* Working backwards:
* 44100 Hz: 45 samples transferred every frame (*2ch * 2bytes) = 180 bytes every frame
* 48000 Hz: 48 samples transferred every frame (*2ch * 2bytes) = 192 bytes every frame
* 192000 Hz: *2ch *2bytes = 768 bytes every frame
*
* We appear to be more limited by our PCM system's need to gobble up data at startup.
* This may actually, contrary to intuition, make us need a higher number of buffers
* for _lower_ sample rates, as we will need more buffers' worth of data up-front due to
* lower amounts of data in each USB frame (assuming the mixer wants the same amount of data upfront
* regardless of sample rate).
*
* Making the executive decision to only export frequencies 44.1k+.
*/
#define NR_BUFFERS 32
#define MINIMUM_BUFFERS_QUEUED 16
/* size of each buffer: must be smaller than 1023 (max isochronous packet size) */
#define BUFFER_SIZE 1023
/* make sure each buffer size is actually a multiple of 32 bytes to avoid any
* issue with strange alignements */
#define REAL_BUF_SIZE ALIGN_UP(BUFFER_SIZE, 32)
bool alloc_failed = false;
bool usb_audio_playing = false;
int tmp_saved_vol;
/* buffers used for usb, queuing and playback */
static unsigned char *rx_buffer;
int rx_buffer_handle;
/* buffer size */
static int rx_buf_size[NR_BUFFERS]; // only used for debug screen counter now
/* index of the next buffer to play */
static int rx_play_idx;
/* index of the next buffer to fill */
static int rx_usb_idx;
/* playback underflowed ? */
bool playback_audio_underflow;
/* usb overflow ? */
bool usb_rx_overflow;
/* dsp processing buffers */
#define DSP_BUF_SIZE (BUFFER_SIZE*4) // arbitrarily x4
#define REAL_DSP_BUF_SIZE ALIGN_UP(DSP_BUF_SIZE, 32)
static uint16_t *dsp_buf;
int dsp_buf_handle;
static int dsp_buf_size[NR_BUFFERS];
struct dsp_config *dsp = NULL;
/* feedback variables */
#define USB_FRAME_MAX 0x7FF
#define NR_SAMPLES_HISTORY 32
int32_t samples_fb;
int32_t buffers_filled_old;
long buffers_filled_accumulator;
long buffers_filled_accumulator_old;
int buffers_filled_avgcount;
int buffers_filled_avgcount_old;
static uint8_t sendFf[4] USB_DEVBSS_ATTR;
static bool sent_fb_this_frame = false;
int fb_startframe = 0;
bool send_fb = false;
/* debug screen sample count display variables */
static unsigned long samples_received;
static unsigned long samples_received_last;
int32_t samples_received_report;
int buffers_filled_min;
int buffers_filled_min_last;
int buffers_filled_max;
int buffers_filled_max_last;
/* frame drop recording variables */
static int last_frame = 0;
static int frames_dropped = 0;
/* for blocking normal playback */
static bool usbaudio_active = false;
/* Schematic view of the RX situation:
* (in case NR_BUFFERS = 4)
*
* +--------+ +--------+ +--------+ +--------+
* | | | | | | | |
* | buf[0] | ---> | buf[1] | ---> | buf[2] | ---> | buf[3] | ---> (back to buf[0])
* | | | | | | | |
* +--------+ +--------+ +--------+ +--------+
* ^ ^ ^ ^
* | | | |
* rx_play_idx (buffer rx_usb_idx (empty buffer)
* (buffer being filled) (buffer being
* played) filled)
*
* Error handling:
* in the RX situation, there are two possible errors
* - playback underflow: playback wants more data but we don't have any to
* provide, so we have to stop audio and wait for some prebuffering before
* starting again
* - usb overflow: usb wants to send more data but don't have any more free buffers,
* so we have to pause usb reception and wait for some playback buffer to become
* free again
*/
/* USB Audio encodes frequencies with 3 bytes... */
static void encode3(uint8_t arr[3], unsigned long freq)
{
/* ugly */
arr[0] = freq & 0xff;
arr[1] = (freq >> 8) & 0xff;
arr[2] = (freq >> 16) & 0xff;
}
static unsigned long decode3(uint8_t arr[3])
{
return arr[0] | (arr[1] << 8) | (arr[2] << 16);
}
// size is samples per frame!
static void encodeFBfixedpt(uint8_t arr[4], int32_t value, bool portspeed)
{
uint32_t fixedpt;
// high-speed
if (portspeed)
{
// Q16.16
fixedpt = value;
arr[0] = (fixedpt & 0xFF);
arr[1] = (fixedpt>>8) & 0xFF;
arr[2] = (fixedpt>>16) & 0xFF;
arr[3] = (fixedpt>>24) & 0xFF;
}
else // full-speed
{
// Q16.16 --> Q10.10 --> Q10.14
fixedpt = value / (1<<2); // convert from Q16.16 to Q10.14
// then aligned so it's more like Q10.14
// NOTE: this line left for posterity
// fixedpt = fixedpt << (4);
arr[0] = (fixedpt & 0xFF);
arr[1] = (fixedpt>>8) & 0xFF;
arr[2] = (fixedpt>>16) & 0xFF;
}
}
static void set_playback_sampling_frequency(unsigned long f)
{
// only values 44.1k and higher (array is in descending order)
for(int i = 0; i <= HW_FREQ_44; i++)
{
/* compare errors */
int err = abs((long)hw_freq_sampr[i] - (long)f);
int best_err = abs((long)hw_freq_sampr[as_playback_freq_idx] - (long)f);
if(err < best_err)
as_playback_freq_idx = i;
}
logf("usbaudio: set playback sampling frequency to %lu Hz for a requested %lu Hz",
hw_freq_sampr[as_playback_freq_idx], f);
mixer_set_frequency(hw_freq_sampr[as_playback_freq_idx]);
pcm_apply_settings();
}
unsigned long usb_audio_get_playback_sampling_frequency(void)
{
// logf("usbaudio: get playback sampl freq %lu Hz", hw_freq_sampr[as_playback_freq_idx]);
return hw_freq_sampr[as_playback_freq_idx];
}
void usb_audio_init(void)
{
unsigned int i;
/* initialized tSamFreq array */
logf("usbaudio: (init) supported frequencies");
// only values 44.1k and higher (array is in descending order)
for(i = 0; i <= HW_FREQ_44; i++)
{
logf("usbaudio: %lu Hz", hw_freq_sampr[i]);
encode3(as_playback_format_type_i.tSamFreq[i], hw_freq_sampr[i]);
}
}
int usb_audio_request_buf(void)
{
// stop playback first thing
audio_stop();
// attempt to allocate the receive buffers
rx_buffer_handle = core_alloc(REAL_BUF_SIZE);
if (rx_buffer_handle < 0)
{
alloc_failed = true;
return -1;
}
else
{
alloc_failed = false;
// "pin" the allocation so that the core does not move it in memory
core_pin(rx_buffer_handle);
// get the pointer to the actual buffer location
rx_buffer = core_get_data(rx_buffer_handle);
}
dsp_buf_handle = core_alloc(NR_BUFFERS * REAL_DSP_BUF_SIZE);
if (dsp_buf_handle < 0)
{
alloc_failed = true;
rx_buffer_handle = core_free(rx_buffer_handle);
rx_buffer = NULL;
return -1;
}
else
{
alloc_failed = false;
core_pin(dsp_buf_handle);
dsp_buf = core_get_data(dsp_buf_handle);
}
// logf("usbaudio: got buffer");
return 0;
}
void usb_audio_free_buf(void)
{
// logf("usbaudio: free buffer");
rx_buffer_handle = core_free(rx_buffer_handle);
rx_buffer = NULL;
dsp_buf_handle = core_free(dsp_buf_handle);
dsp_buf = NULL;
}
int usb_audio_request_endpoints(struct usb_class_driver *drv)
{
// make sure we can get the buffers first...
// return -1 if the allocation _failed_
if (usb_audio_request_buf())
return -1;
out_iso_ep_adr = usb_core_request_endpoint(USB_ENDPOINT_XFER_ISOC, USB_DIR_OUT, drv);
if(out_iso_ep_adr < 0)
{
logf("usbaudio: cannot get an out iso endpoint");
return -1;
}
in_iso_feedback_ep_adr = usb_core_request_endpoint(USB_ENDPOINT_XFER_ISOC, USB_DIR_IN, drv);
if(in_iso_feedback_ep_adr < 0)
{
usb_core_release_endpoint(out_iso_ep_adr);
logf("usbaudio: cannot get an in iso endpoint");
return -1;
}
logf("usbaudio: iso out ep is 0x%x, in ep is 0x%x", out_iso_ep_adr, in_iso_feedback_ep_adr);
as_iso_audio_out_ep.bEndpointAddress = out_iso_ep_adr;
as_iso_audio_out_ep.bSynchAddress = in_iso_feedback_ep_adr;
as_iso_synch_in_ep.bEndpointAddress = in_iso_feedback_ep_adr;
as_iso_synch_in_ep.bSynchAddress = 0;
return 0;
}
unsigned int usb_audio_get_out_ep(void)
{
return out_iso_ep_adr;
}
unsigned int usb_audio_get_in_ep(void)
{
return in_iso_feedback_ep_adr;
}
int usb_audio_set_first_interface(int interface)
{
usb_interface = interface;
logf("usbaudio: usb_interface=%d", usb_interface);
return interface + 2; /* Audio Control and Audio Streaming */
}
int usb_audio_get_config_descriptor(unsigned char *dest, int max_packet_size)
{
(void)max_packet_size;
unsigned int i;
unsigned char *orig_dest = dest;
logf("get config descriptors");
/** Configuration */
/* header */
ac_header.baInterfaceNr[0] = usb_interface + 1;
/* audio control interface */
ac_interface.bInterfaceNumber = usb_interface;
/* compute total size of AC headers*/
ac_header.wTotalLength = 0;
for(i = 0; i < AC_CS_DESCRIPTORS_LIST_SIZE; i++)
ac_header.wTotalLength += ac_cs_descriptors_list[i]->bLength;
/* audio streaming */
as_interface_alt_idle_playback.bInterfaceNumber = usb_interface + 1;
as_interface_alt_playback.bInterfaceNumber = usb_interface + 1;
/* endpoints */
as_iso_audio_out_ep.wMaxPacketSize = 1023;
/** Endpoint Interval calculation:
* typically sampling frequency is 44100 Hz and top is 192000 Hz, which
* account for typical 44100*2(stereo)*2(16-bit) ~= 180 kB/s
* and top 770 kB/s. Since there are ~1000 frames per seconds and maximum
* packet size is set to 1023, one transaction per frame is good enough
* for over 1 MB/s.
* Recall that actual is 2^(bInterval - 1) */
/* In simpler language, This is intended to emulate full-speed's
* one-packet-per-frame rate on high-speed, where we have multiple microframes per millisecond.
*/
as_iso_audio_out_ep.bInterval = usb_drv_port_speed() ? 4 : 1;
as_iso_synch_in_ep.bInterval = usb_drv_port_speed() ? 4 : 1; // per spec
logf("usbaudio: port_speed=%s", usb_drv_port_speed()?"hs":"fs");
/** Packing */
for(i = 0; i < USB_DESCRIPTORS_LIST_SIZE; i++)
{
memcpy(dest, usb_descriptors_list[i], usb_descriptors_list[i]->bLength);
dest += usb_descriptors_list[i]->bLength;
}
return dest - orig_dest;
}
static void playback_audio_get_more(const void **start, size_t *size)
{
/* if there are no more filled buffers, playback has just underflowed */
if(rx_play_idx == rx_usb_idx)
{
logf("usbaudio: playback underflow");
playback_audio_underflow = true;
*start = NULL;
*size = 0;
return;
}
/* give buffer and advance */
logf("usbaudio: buf adv");
*start = dsp_buf + (rx_play_idx * REAL_DSP_BUF_SIZE/sizeof(*dsp_buf));
*size = dsp_buf_size[rx_play_idx];
rx_play_idx = (rx_play_idx + 1) % NR_BUFFERS;
/* if usb RX buffers had overflowed, we can start to receive again
* guard against IRQ to avoid race with completion usb completion (although
* this function is probably running in IRQ context anyway) */
int oldlevel = disable_irq_save();
if(usb_rx_overflow)
{
logf("usbaudio: recover usb rx overflow");
usb_rx_overflow = false;
usb_drv_recv_nonblocking(out_iso_ep_adr, rx_buffer, BUFFER_SIZE);
}
restore_irq(oldlevel);
}
static void usb_audio_start_playback(void)
{
usb_audio_playing = true;
usb_rx_overflow = false;
playback_audio_underflow = true;
rx_play_idx = 0;
rx_usb_idx = 0;
// feedback initialization
fb_startframe = usb_drv_get_frame_number();
samples_fb = 0;
samples_received_report = 0;
// debug screen info - frame drop counter
frames_dropped = 0;
last_frame = -1;
buffers_filled_min = -1;
buffers_filled_min_last = -1;
buffers_filled_max = -1;
buffers_filled_max_last = -1;
// debug screen info - sample counters
samples_received = 0;
samples_received_last = 0;
// TODO: implement recording from the USB stream
#if (INPUT_SRC_CAPS != 0)
audio_set_input_source(AUDIO_SRC_PLAYBACK, SRCF_PLAYBACK);
audio_set_output_source(AUDIO_SRC_PLAYBACK);
#endif
logf("usbaudio: start playback at %lu Hz", hw_freq_sampr[as_playback_freq_idx]);
mixer_set_frequency(hw_freq_sampr[as_playback_freq_idx]);
pcm_apply_settings();
mixer_channel_set_amplitude(PCM_MIXER_CHAN_USBAUDIO, MIX_AMP_UNITY);
usb_drv_recv_nonblocking(out_iso_ep_adr, rx_buffer, BUFFER_SIZE);
}
static void usb_audio_stop_playback(void)
{
logf("usbaudio: stop playback");
if(usb_audio_playing)
{
mixer_channel_stop(PCM_MIXER_CHAN_USBAUDIO);
usb_audio_playing = false;
}
send_fb = false;
}
int usb_audio_set_interface(int intf, int alt)
{
if(intf == usb_interface)
{
if(alt != 0)
{
logf("usbaudio: control interface has no alternate %d", alt);
return -1;
}
return 0;
}
if(intf == (usb_interface + 1))
{
if(alt < 0 || alt > 1)
{
logf("usbaudio: playback interface has no alternate %d", alt);
return -1;
}
usb_as_playback_intf_alt = alt;
if(usb_as_playback_intf_alt == 1)
usb_audio_start_playback();
else
usb_audio_stop_playback();
logf("usbaudio: use playback alternate %d", alt);
return 0;
}
else
{
logf("usbaudio: interface %d has no alternate", intf);
return -1;
}
}
int usb_audio_get_interface(int intf)
{
if(intf == usb_interface)
{
logf("usbaudio: control interface alternate is 0");
return 0;
}
else if(intf == (usb_interface + 1))
{
logf("usbaudio: playback interface alternate is %d", usb_as_playback_intf_alt);
return usb_as_playback_intf_alt;
}
else
{
logf("usbaudio: unknown interface %d", intf);
return -1;
}
}
int usb_audio_get_main_intf(void)
{
return usb_interface;
}
int usb_audio_get_alt_intf(void)
{
return usb_as_playback_intf_alt;
}
int32_t usb_audio_get_samplesperframe(void)
{
return samples_fb;
}
int32_t usb_audio_get_samples_rx_perframe(void)
{
return samples_received_report;
}
static bool usb_audio_as_ctrldata_endpoint_request(struct usb_ctrlrequest* req, void *reqdata)
{
/* only support sampling frequency */
if(req->wValue != (USB_AS_EP_CS_SAMPLING_FREQ_CTL << 8))
{
logf("usbaudio: endpoint only handles sampling frequency control");
return false;
}
switch(req->bRequest)
{
case USB_AC_SET_CUR:
if(req->wLength != 3)
{
logf("usbaudio: bad length for SET_CUR");
usb_drv_control_response(USB_CONTROL_STALL, NULL, 0);
return true;
}
logf("usbaudio: SET_CUR sampling freq");
if (reqdata) { /* control write, second pass */
set_playback_sampling_frequency(decode3(reqdata));
usb_drv_control_response(USB_CONTROL_ACK, NULL, 0);
return true;
} else { /* control write, first pass */
bool error = false;
if (req->wLength != 3)
error = true;
/* ... other validation? */
if (error)
usb_drv_control_response(USB_CONTROL_STALL, NULL, 0);
else
usb_drv_control_response(USB_CONTROL_RECEIVE, usb_buffer, 3);
return true;
}
case USB_AC_GET_CUR:
if(req->wLength != 3)
{
logf("usbaudio: bad length for GET_CUR");
usb_drv_control_response(USB_CONTROL_STALL, NULL, 0);
return true;
}
logf("usbaudio: GET_CUR sampling freq");
encode3(usb_buffer, usb_audio_get_playback_sampling_frequency());
usb_drv_control_response(USB_CONTROL_ACK, usb_buffer, req->wLength);
return true;
default:
logf("usbaudio: unhandled ep req 0x%x", req->bRequest);
}
return true;
}
static bool usb_audio_endpoint_request(struct usb_ctrlrequest* req, void *reqdata)
{
int ep = req->wIndex & 0xff;
if(ep == out_iso_ep_adr)
return usb_audio_as_ctrldata_endpoint_request(req, reqdata);
else
{
logf("usbaudio: unhandled ep req (ep=%d)", ep);
return false;
}
}
static bool feature_unit_set_mute(int value, uint8_t cmd)
{
if(cmd != USB_AC_CUR_REQ)
{
logf("usbaudio: feature unit MUTE control only has a CUR setting");
return false;
}
if(value == 1)
{
logf("usbaudio: mute !");
tmp_saved_vol = sound_current(SOUND_VOLUME);
// setvol does range checking for us!
global_status.volume = sound_min(SOUND_VOLUME);
setvol();
return true;
}
else if(value == 0)
{
logf("usbaudio: not muted !");
// setvol does range checking for us!
global_status.volume = tmp_saved_vol;
setvol();
return true;
}
else
{
logf("usbaudio: invalid value for CUR setting of feature unit (%d)", value);
return false;
}
}
static bool feature_unit_get_mute(int *value, uint8_t cmd)
{
if(cmd != USB_AC_CUR_REQ)
{
logf("usbaudio: feature unit MUTE control only has a CUR setting");
return false;
}
*value = (sound_current(SOUND_VOLUME) == sound_min(SOUND_VOLUME));
return true;
}
/*
* USB volume is a signed 16-bit value, -127.9961 dB (0x8001) to +127.9961 dB (0x7FFF)
* in steps of 1/256 dB (0.00390625 dB)
*
* We need to account for different devices having different numbers of decimals
*/
// TODO: do we need to explicitly round these? Will we have a "walking" round conversion issue?
// Step values of 1 dB (and multiples), and 0.5 dB should be able to be met exactly,
// presuming that it starts on an even number.
static int usb_audio_volume_to_db(int vol, int numdecimals)
{
int tmp = (signed long)((signed short)vol * ipow(10, numdecimals)) / 256;
// logf("vol=0x%04X, numdecimals=%d, tmp=%d", vol, numdecimals, tmp);
return tmp;
}
static int db_to_usb_audio_volume(int db, int numdecimals)
{
int tmp = (signed long)(db * 256) / ipow(10, numdecimals);
// logf("db=%d, numdecimals=%d, tmpTodB=%d", db, numdecimals, usb_audio_volume_to_db(tmp, numdecimals));
return tmp;
}
#if defined(LOGF_ENABLE) && defined(ROCKBOX_HAS_LOGF)
static const char *usb_audio_ac_ctl_req_str(uint8_t cmd)
{
switch(cmd)
{
case USB_AC_CUR_REQ: return "CUR";
case USB_AC_MIN_REQ: return "MIN";
case USB_AC_MAX_REQ: return "MAX";
case USB_AC_RES_REQ: return "RES";
case USB_AC_MEM_REQ: return "MEM";
default: return "<unknown>";
}
}
#endif
static bool feature_unit_set_volume(int value, uint8_t cmd)
{
if(cmd != USB_AC_CUR_REQ)
{
logf("usbaudio: feature unit VOLUME doesn't support %s setting", usb_audio_ac_ctl_req_str(cmd));
return false;
}
logf("usbaudio: set volume=%d dB", usb_audio_volume_to_db(value, sound_numdecimals(SOUND_VOLUME)));
// setvol does range checking for us!
// we cannot guarantee the host will send us a volume within our range
global_status.volume = usb_audio_volume_to_db(value, sound_numdecimals(SOUND_VOLUME));
setvol();
return true;
}
static bool feature_unit_get_volume(int *value, uint8_t cmd)
{
switch(cmd)
{
case USB_AC_CUR_REQ: *value = db_to_usb_audio_volume(sound_current(SOUND_VOLUME), sound_numdecimals(SOUND_VOLUME)); break;
case USB_AC_MIN_REQ: *value = db_to_usb_audio_volume(sound_min(SOUND_VOLUME), sound_numdecimals(SOUND_VOLUME)); break;
case USB_AC_MAX_REQ: *value = db_to_usb_audio_volume(sound_max(SOUND_VOLUME), sound_numdecimals(SOUND_VOLUME)); break;
case USB_AC_RES_REQ: *value = db_to_usb_audio_volume(sound_steps(SOUND_VOLUME), sound_numdecimals(SOUND_VOLUME)); break;
default:
logf("usbaudio: feature unit VOLUME doesn't support %s setting", usb_audio_ac_ctl_req_str(cmd));
return false;
}
// logf("usbaudio: get %s volume=%d dB", usb_audio_ac_ctl_req_str(cmd), usb_audio_volume_to_db(*value, sound_numdecimals(SOUND_VOLUME)));
return true;
}
int usb_audio_get_cur_volume(void)
{
int vol;
feature_unit_get_volume(&vol, USB_AC_CUR_REQ);
return usb_audio_volume_to_db(vol, sound_numdecimals(SOUND_VOLUME));
}
static bool usb_audio_set_get_feature_unit(struct usb_ctrlrequest* req, void *reqdata)
{
int channel = req->wValue & 0xff;
int selector = req->wValue >> 8;
uint8_t cmd = (req->bRequest & ~USB_AC_GET_REQ);
int value = 0;
int i;
bool handled;
/* master channel only */
if(channel != 0)
{
logf("usbaudio: set/get on feature unit only apply to master channel (%d)", channel);
return false;
}
/* selectors */
/* all send/received values are integers already - read data if necessary and store in it in an integer */
if(req->bRequest & USB_AC_GET_REQ)
{
/* get */
switch(selector)
{
case USB_AC_FU_MUTE:
handled = (req->wLength == 1) && feature_unit_get_mute(&value, cmd);
break;
case USB_AC_VOLUME_CONTROL:
handled = (req->wLength == 2) && feature_unit_get_volume(&value, cmd);
break;
default:
handled = false;
logf("usbaudio: unhandled control selector of feature unit (0x%x)", selector);
break;
}
if(!handled)
{
logf("usbaudio: unhandled get control 0x%x selector 0x%x of feature unit", cmd, selector);
usb_drv_control_response(USB_CONTROL_STALL, NULL, 0);
return true;
}
if(req->wLength == 0 || req->wLength > 4)
{
logf("usbaudio: get data payload size is invalid (%d)", req->wLength);
return false;
}
for(i = 0; i < req->wLength; i++)
usb_buffer[i] = (value >> (8 * i)) & 0xff;
usb_drv_control_response(USB_CONTROL_ACK, usb_buffer, req->wLength);
return true;
}
else
{
/* set */
if(req->wLength == 0 || req->wLength > 4)
{
logf("usbaudio: set data payload size is invalid (%d)", req->wLength);
return false;
}
if (reqdata) {
for(i = 0; i < req->wLength; i++)
value = value | (usb_buffer[i] << (i * 8));
switch(selector)
{
case USB_AC_FU_MUTE:
handled = (req->wLength == 1) && feature_unit_set_mute(value, cmd);
break;
case USB_AC_VOLUME_CONTROL:
handled = (req->wLength == 2) && feature_unit_set_volume(value, cmd);
break;
default:
handled = false;
logf("usbaudio: unhandled control selector of feature unit (0x%x)", selector);
break;
}
if(!handled)
{
logf("usbaudio: unhandled set control 0x%x selector 0x%x of feature unit", cmd, selector);
usb_drv_control_response(USB_CONTROL_STALL, NULL, 0);
return true;
}
usb_drv_control_response(USB_CONTROL_ACK, NULL, 0);
return true;
} else {
/*
* should handle the following (req->wValue >> 8):
* USB_AC_FU_MUTE
* USB_AC_VOLUME_CONTROL
*/
bool error = false;
if (error)
usb_drv_control_response(USB_CONTROL_STALL, NULL, 0);
else
usb_drv_control_response(USB_CONTROL_RECEIVE, usb_buffer, 3);
return true;
}
return true;
}
}
static bool usb_audio_ac_set_get_request(struct usb_ctrlrequest* req, void *reqdata)
{
switch(req->wIndex >> 8)
{
case AC_PLAYBACK_FEATURE_ID:
return usb_audio_set_get_feature_unit(req, reqdata);
default:
logf("usbaudio: unhandled set/get on entity %d", req->wIndex >> 8);
return false;
}
}
static bool usb_audio_interface_request(struct usb_ctrlrequest* req, void *reqdata)
{
int intf = req->wIndex & 0xff;
if(intf == usb_interface)
{
switch(req->bRequest)
{
case USB_AC_SET_CUR: case USB_AC_SET_MIN: case USB_AC_SET_MAX: case USB_AC_SET_RES:
case USB_AC_SET_MEM: case USB_AC_GET_CUR: case USB_AC_GET_MIN: case USB_AC_GET_MAX:
case USB_AC_GET_RES: case USB_AC_GET_MEM:
return usb_audio_ac_set_get_request(req, reqdata);
default:
logf("usbaudio: unhandled ac intf req 0x%x", req->bRequest);
return false;
}
}
else
{
logf("usbaudio: unhandled intf req (intf=%d)", intf);
return false;
}
}
bool usb_audio_control_request(struct usb_ctrlrequest* req, void *reqdata, unsigned char* dest)
{
(void) reqdata;
(void) dest;
switch(req->bRequestType & USB_RECIP_MASK)
{
case USB_RECIP_ENDPOINT:
return usb_audio_endpoint_request(req, reqdata);
case USB_RECIP_INTERFACE:
return usb_audio_interface_request(req, reqdata);
default:
logf("usbaudio: unhandled req type 0x%x", req->bRequestType);
return false;
}
}
void usb_audio_init_connection(void)
{
logf("usbaudio: init connection");
usbaudio_active = true;
dsp = dsp_get_config(CODEC_IDX_AUDIO);
dsp_configure(dsp, DSP_RESET, 0);
dsp_configure(dsp, DSP_SET_STEREO_MODE, STEREO_INTERLEAVED);
dsp_configure(dsp, DSP_SET_SAMPLE_DEPTH, 16);
#ifdef HAVE_PITCHCONTROL
sound_set_pitch(PITCH_SPEED_100);
dsp_set_timestretch(PITCH_SPEED_100);
#endif
usb_as_playback_intf_alt = 0;
set_playback_sampling_frequency(HW_SAMPR_DEFAULT);
tmp_saved_vol = sound_current(SOUND_VOLUME);
usb_audio_playing = false;
}
void usb_audio_disconnect(void)
{
logf("usbaudio: disconnect");
usb_audio_stop_playback();
usb_audio_free_buf();
usbaudio_active = false;
}
bool usb_audio_get_active(void)
{
return usbaudio_active;
}
bool usb_audio_get_alloc_failed(void)
{
return alloc_failed;
}
bool usb_audio_get_playing(void)
{
return usb_audio_playing;
}
/* determine if enough prebuffering has been done to restart audio */
bool prebuffering_done(void)
{
/* restart audio if at least MINIMUM_BUFFERS_QUEUED buffers are filled */
int diff = (rx_usb_idx - rx_play_idx + NR_BUFFERS) % NR_BUFFERS;
return diff >= MINIMUM_BUFFERS_QUEUED;
}
int usb_audio_get_prebuffering(void)
{
return (rx_usb_idx - rx_play_idx + NR_BUFFERS) % NR_BUFFERS;
}
int32_t usb_audio_get_prebuffering_avg(void)
{
if (buffers_filled_avgcount == 0)
{
return TO_16DOT16_FIXEDPT(usb_audio_get_prebuffering());
} else {
return (TO_16DOT16_FIXEDPT(buffers_filled_accumulator)/buffers_filled_avgcount) + TO_16DOT16_FIXEDPT(MINIMUM_BUFFERS_QUEUED);
}
}
int usb_audio_get_prebuffering_maxmin(bool max)
{
if (max)
{
return buffers_filled_max == -1 ? buffers_filled_max_last : buffers_filled_max;
}
else
{
return buffers_filled_min == -1 ? buffers_filled_min_last : buffers_filled_min;
}
}
bool usb_audio_get_underflow(void)
{
return playback_audio_underflow;
}
bool usb_audio_get_overflow(void)
{
return usb_rx_overflow;
}
int usb_audio_get_frames_dropped(void)
{
return frames_dropped;
}
void usb_audio_transfer_complete(int ep, int dir, int status, int length)
{
/* normal handler is too slow to handle the completion rate, because
* of the low thread schedule rate */
(void) ep;
(void) dir;
(void) status;
(void) length;
}
bool usb_audio_fast_transfer_complete(int ep, int dir, int status, int length)
{
(void) dir;
bool retval = false;
if(ep == out_iso_ep_adr && usb_as_playback_intf_alt == 1)
{
// check for dropped frames
if (last_frame != usb_drv_get_frame_number())
{
if ((((last_frame + 1) % (USB_FRAME_MAX + 1)) != usb_drv_get_frame_number()) && (last_frame != -1))
{
frames_dropped++;
}
last_frame = usb_drv_get_frame_number();
}
// If audio and feedback EPs happen to have the same base number (with opposite directions, of course),
// we will get replies to the feedback here, don't want that to be interpreted as data.
if (length <= 4)
{
return true;
}
logf("usbaudio: frame: %d bytes: %d", usb_drv_get_frame_number(), length);
if(status != 0)
return true; /* FIXME how to handle error here ? */
/* store length, queue buffer */
rx_buf_size[rx_usb_idx] = length;
// debug screen counter
samples_received = samples_received + length;
// process through DSP right away!
struct dsp_buffer src;
src.remcount = length/4; // in samples
src.pin[0] = rx_buffer;
src.proc_mask = 0;
struct dsp_buffer dst;
dst.remcount = 0;
dst.bufcount = DSP_BUF_SIZE/4; // in samples
dst.p16out = dsp_buf + (rx_usb_idx * REAL_DSP_BUF_SIZE/sizeof(*dsp_buf)); // array index
dsp_process(dsp, &src, &dst, false);
dsp_buf_size[rx_usb_idx] = dst.remcount * 2 * sizeof(*dsp_buf); // need value in bytes
rx_usb_idx = (rx_usb_idx + 1) % NR_BUFFERS;
/* guard against IRQ to avoid race with completion audio completion */
int oldlevel = disable_irq_save();
/* setup a new transaction except if we ran out of buffers */
if(rx_usb_idx != rx_play_idx)
{
logf("usbaudio: new transaction");
usb_drv_recv_nonblocking(out_iso_ep_adr, rx_buffer, BUFFER_SIZE);
}
else
{
logf("usbaudio: rx overflow");
usb_rx_overflow = true;
}
/* if audio underflowed and prebuffering is done, restart audio */
if(playback_audio_underflow && prebuffering_done())
{
logf("usbaudio: prebuffering done");
playback_audio_underflow = false;
usb_rx_overflow = false;
mixer_channel_play_data(PCM_MIXER_CHAN_USBAUDIO, playback_audio_get_more, NULL, 0);
}
restore_irq(oldlevel);
retval = true;
}
else
{
retval = false;
}
// send feedback value every N frames!
// NOTE: important that we need to queue this up _the frame before_ it's needed - on MacOS especially!
if ((usb_drv_get_frame_number()+1) % FEEDBACK_UPDATE_RATE_FRAMES == 0 && send_fb)
{
if (!sent_fb_this_frame)
{
/* NOTE: the division of frequency must be staged to avoid overflow of 16-bit signed int
* as well as truncating the result to ones place!
* Must avoid values > 32,768 (2^15)
* Largest value: 192,000 --> /10: 19,200 --> /100: 192
* Smallest value: 44,100 --> /10: 4,410 --> /100: 44.1
*/
int32_t samples_base = TO_16DOT16_FIXEDPT(hw_freq_sampr[as_playback_freq_idx]/10)/100;
int32_t buffers_filled = 0;
if (buffers_filled_avgcount != 0)
{
buffers_filled = TO_16DOT16_FIXEDPT((int32_t)buffers_filled_accumulator) / buffers_filled_avgcount;
}
buffers_filled_accumulator = buffers_filled_accumulator - buffers_filled_accumulator_old;
buffers_filled_avgcount = buffers_filled_avgcount - buffers_filled_avgcount_old;
buffers_filled_accumulator_old = buffers_filled_accumulator;
buffers_filled_avgcount_old = buffers_filled_avgcount;
// someone who has implemented actual PID before might be able to do this correctly,
// but this seems to work good enough?
// Coefficients were 1, 0.25, 0.025 in float math --> 1, /4, /40 in fixed-point math
samples_fb = samples_base - (buffers_filled/4) + ((buffers_filled_old - buffers_filled)/40);
buffers_filled_old = buffers_filled;
// must limit to +/- 1 sample from nominal
samples_fb = samples_fb > (samples_base + TO_16DOT16_FIXEDPT(1)) ? samples_base + TO_16DOT16_FIXEDPT(1) : samples_fb;
samples_fb = samples_fb < (samples_base - TO_16DOT16_FIXEDPT(1)) ? samples_base - TO_16DOT16_FIXEDPT(1) : samples_fb;
encodeFBfixedpt(sendFf, samples_fb, usb_drv_port_speed());
logf("usbaudio: frame %d fbval 0x%02X%02X%02X%02X", usb_drv_get_frame_number(), sendFf[3], sendFf[2], sendFf[1], sendFf[0]);
usb_drv_send_nonblocking(in_iso_feedback_ep_adr, sendFf, usb_drv_port_speed()?4:3);
// debug screen counters
//
// samples_received NOTE: need some "division staging" to not overflow signed 16-bit value
// samples / (feedback frames * 2) --> samples/2
// samples_report / (2ch * 2bytes per sample) --> samples/4
// total: samples/8
samples_received_report = TO_16DOT16_FIXEDPT(samples_received/8) / FEEDBACK_UPDATE_RATE_FRAMES;
samples_received = samples_received - samples_received_last;
samples_received_last = samples_received;
buffers_filled_max_last = buffers_filled_max;
buffers_filled_max = -1;
buffers_filled_min_last = buffers_filled_min;
buffers_filled_min = -1;
}
sent_fb_this_frame = true;
}
else
{
sent_fb_this_frame = false;
if (!send_fb)
{
// arbitrary wait during startup
if (usb_drv_get_frame_number() == (fb_startframe + (FEEDBACK_UPDATE_RATE_FRAMES*2))%(USB_FRAME_MAX+1))
{
send_fb = true;
}
}
buffers_filled_accumulator = buffers_filled_accumulator + (usb_audio_get_prebuffering() - MINIMUM_BUFFERS_QUEUED);
buffers_filled_avgcount++;
if (usb_audio_get_prebuffering() < buffers_filled_min || buffers_filled_min == -1)
{
buffers_filled_min = usb_audio_get_prebuffering();
} else if (usb_audio_get_prebuffering() > buffers_filled_max)
{
buffers_filled_max = usb_audio_get_prebuffering();
}
}
return retval;
}