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Subject[PATCH v2 2/7] ALSA: usb: stream: refactor uac1/2 audio interface parsing
Date
Offload snd_usb_parse_audio_interface() function
which became quite long after adding UAC3 spec support.

Move class-specific parts of uac1/2 parsing to separate
function which now produce audioformat structure that
is ready to be fed to snd_usb_add_audio_stream().

This also broke Blue Microphones workaround (which
relies on audioformat decoded from previous altsetting)
into two parts: prepare quirk flag analyzing previous
altsetting then use it with current altsetting.

Signed-off-by: Ruslan Bilovol <ruslan.bilovol@gmail.com>
---
sound/usb/stream.c | 333 +++++++++++++++++++++++++++++------------------------
1 file changed, 185 insertions(+), 148 deletions(-)

diff --git a/sound/usb/stream.c b/sound/usb/stream.c
index 8ec0a52..3369226 100644
--- a/sound/usb/stream.c
+++ b/sound/usb/stream.c
@@ -656,6 +656,156 @@ static int parse_uac_endpoint_attributes(struct snd_usb_audio *chip,
return fp;
}

+static struct audioformat *
+snd_usb_get_audioformat_uac12(struct snd_usb_audio *chip,
+ struct usb_host_interface *alts,
+ int protocol, int iface_no, int altset_idx,
+ int altno, int stream, int bm_quirk)
+{
+ struct usb_device *dev = chip->dev;
+ struct uac_format_type_i_continuous_descriptor *fmt;
+ unsigned int num_channels = 0, chconfig = 0;
+ struct audioformat *fp;
+ int clock = 0;
+ u64 format;
+
+ /* get audio formats */
+ if (protocol == UAC_VERSION_1) {
+ struct uac1_as_header_descriptor *as =
+ snd_usb_find_csint_desc(alts->extra, alts->extralen,
+ NULL, UAC_AS_GENERAL);
+ struct uac_input_terminal_descriptor *iterm;
+
+ if (!as) {
+ dev_err(&dev->dev,
+ "%u:%d : UAC_AS_GENERAL descriptor not found\n",
+ iface_no, altno);
+ return NULL;
+ }
+
+ if (as->bLength < sizeof(*as)) {
+ dev_err(&dev->dev,
+ "%u:%d : invalid UAC_AS_GENERAL desc\n",
+ iface_no, altno);
+ return NULL;
+ }
+
+ format = le16_to_cpu(as->wFormatTag); /* remember the format value */
+
+ iterm = snd_usb_find_input_terminal_descriptor(chip->ctrl_intf,
+ as->bTerminalLink);
+ if (iterm) {
+ num_channels = iterm->bNrChannels;
+ chconfig = le16_to_cpu(iterm->wChannelConfig);
+ }
+ } else { /* UAC_VERSION_2 */
+ struct uac2_input_terminal_descriptor *input_term;
+ struct uac2_output_terminal_descriptor *output_term;
+ struct uac2_as_header_descriptor *as =
+ snd_usb_find_csint_desc(alts->extra, alts->extralen,
+ NULL, UAC_AS_GENERAL);
+
+ if (!as) {
+ dev_err(&dev->dev,
+ "%u:%d : UAC_AS_GENERAL descriptor not found\n",
+ iface_no, altno);
+ return NULL;
+ }
+
+ if (as->bLength < sizeof(*as)) {
+ dev_err(&dev->dev,
+ "%u:%d : invalid UAC_AS_GENERAL desc\n",
+ iface_no, altno);
+ return NULL;
+ }
+
+ num_channels = as->bNrChannels;
+ format = le32_to_cpu(as->bmFormats);
+ chconfig = le32_to_cpu(as->bmChannelConfig);
+
+ /*
+ * lookup the terminal associated to this interface
+ * to extract the clock
+ */
+ input_term = snd_usb_find_input_terminal_descriptor(chip->ctrl_intf,
+ as->bTerminalLink);
+ if (input_term) {
+ clock = input_term->bCSourceID;
+ if (!chconfig && (num_channels == input_term->bNrChannels))
+ chconfig = le32_to_cpu(input_term->bmChannelConfig);
+ goto found_clock;
+ }
+
+ output_term = snd_usb_find_output_terminal_descriptor(chip->ctrl_intf,
+ as->bTerminalLink);
+ if (output_term) {
+ clock = output_term->bCSourceID;
+ goto found_clock;
+ }
+
+ dev_err(&dev->dev,
+ "%u:%d : bogus bTerminalLink %d\n",
+ iface_no, altno, as->bTerminalLink);
+ return NULL;
+ }
+
+found_clock:
+ /* get format type */
+ fmt = snd_usb_find_csint_desc(alts->extra, alts->extralen,
+ NULL, UAC_FORMAT_TYPE);
+ if (!fmt) {
+ dev_err(&dev->dev,
+ "%u:%d : no UAC_FORMAT_TYPE desc\n",
+ iface_no, altno);
+ return NULL;
+ }
+ if (((protocol == UAC_VERSION_1) && (fmt->bLength < 8))
+ || ((protocol == UAC_VERSION_2) &&
+ (fmt->bLength < 6))) {
+ dev_err(&dev->dev,
+ "%u:%d : invalid UAC_FORMAT_TYPE desc\n",
+ iface_no, altno);
+ return NULL;
+ }
+
+ /*
+ * Blue Microphones workaround: The last altsetting is
+ * identical with the previous one, except for a larger
+ * packet size, but is actually a mislabeled two-channel
+ * setting; ignore it.
+ *
+ * Part 2: analyze quirk flag and format
+ */
+ if (bm_quirk && fmt->bNrChannels == 1 && fmt->bSubframeSize == 2)
+ return NULL;
+
+ fp = audio_format_alloc_init(chip, alts, protocol, iface_no,
+ altset_idx, altno, num_channels, clock);
+ if (!fp)
+ return ERR_PTR(-ENOMEM);
+
+ fp->attributes = parse_uac_endpoint_attributes(chip, alts, protocol,
+ iface_no);
+
+ /* some quirks for attributes here */
+ snd_usb_audioformat_attributes_quirk(chip, fp, stream);
+
+ /* ok, let's parse further... */
+ if (snd_usb_parse_audio_format(chip, fp, format,
+ fmt, stream) < 0) {
+ kfree(fp->rate_table);
+ kfree(fp);
+ return NULL;
+ }
+
+ /* Create chmap */
+ if (fp->channels != num_channels)
+ chconfig = 0;
+
+ fp->chmap = convert_chmap(fp->channels, chconfig, protocol);
+
+ return fp;
+}

int snd_usb_parse_audio_interface(struct snd_usb_audio *chip, int iface_no)
{
@@ -663,14 +813,13 @@ int snd_usb_parse_audio_interface(struct snd_usb_audio *chip, int iface_no)
struct usb_interface *iface;
struct usb_host_interface *alts;
struct usb_interface_descriptor *altsd;
+ struct uac3_as_header_descriptor *as = NULL;
int i, altno, err, stream;
u64 format = 0;
unsigned int num_channels = 0;
struct audioformat *fp = NULL;
int num, protocol, clock = 0;
- struct uac_format_type_i_continuous_descriptor *fmt = NULL;
struct snd_pcm_chmap_elem *chmap_v3 = NULL;
- unsigned int chconfig;

dev = chip->dev;

@@ -719,98 +868,41 @@ int snd_usb_parse_audio_interface(struct snd_usb_audio *chip, int iface_no)
protocol <= 2)
protocol = UAC_VERSION_1;

- chconfig = 0;
- /* get audio formats */
switch (protocol) {
default:
dev_dbg(&dev->dev, "%u:%d: unknown interface protocol %#02x, assuming v1\n",
iface_no, altno, protocol);
protocol = UAC_VERSION_1;
/* fall through */
-
- case UAC_VERSION_1: {
- struct uac1_as_header_descriptor *as =
- snd_usb_find_csint_desc(alts->extra, alts->extralen, NULL, UAC_AS_GENERAL);
- struct uac_input_terminal_descriptor *iterm;
-
- if (!as) {
- dev_err(&dev->dev,
- "%u:%d : UAC_AS_GENERAL descriptor not found\n",
- iface_no, altno);
- continue;
- }
-
- if (as->bLength < sizeof(*as)) {
- dev_err(&dev->dev,
- "%u:%d : invalid UAC_AS_GENERAL desc\n",
- iface_no, altno);
- continue;
- }
-
- format = le16_to_cpu(as->wFormatTag); /* remember the format value */
-
- iterm = snd_usb_find_input_terminal_descriptor(chip->ctrl_intf,
- as->bTerminalLink);
- if (iterm) {
- num_channels = iterm->bNrChannels;
- chconfig = le16_to_cpu(iterm->wChannelConfig);
- }
-
- break;
- }
-
+ case UAC_VERSION_1:
+ /* fall through */
case UAC_VERSION_2: {
- struct uac2_input_terminal_descriptor *input_term;
- struct uac2_output_terminal_descriptor *output_term;
- struct uac2_as_header_descriptor *as =
- snd_usb_find_csint_desc(alts->extra, alts->extralen, NULL, UAC_AS_GENERAL);
-
- if (!as) {
- dev_err(&dev->dev,
- "%u:%d : UAC_AS_GENERAL descriptor not found\n",
- iface_no, altno);
- continue;
- }
-
- if (as->bLength < sizeof(*as)) {
- dev_err(&dev->dev,
- "%u:%d : invalid UAC_AS_GENERAL desc\n",
- iface_no, altno);
- continue;
- }
+ int bm_quirk = 0;

- num_channels = as->bNrChannels;
- format = le32_to_cpu(as->bmFormats);
- chconfig = le32_to_cpu(as->bmChannelConfig);
-
- /* lookup the terminal associated to this interface
- * to extract the clock */
- input_term = snd_usb_find_input_terminal_descriptor(chip->ctrl_intf,
- as->bTerminalLink);
- if (input_term) {
- clock = input_term->bCSourceID;
- if (!chconfig && (num_channels == input_term->bNrChannels))
- chconfig = le32_to_cpu(input_term->bmChannelConfig);
- break;
- }
-
- output_term = snd_usb_find_output_terminal_descriptor(chip->ctrl_intf,
- as->bTerminalLink);
- if (output_term) {
- clock = output_term->bCSourceID;
- break;
- }
+ /*
+ * Blue Microphones workaround: The last altsetting is
+ * identical with the previous one, except for a larger
+ * packet size, but is actually a mislabeled two-channel
+ * setting; ignore it.
+ *
+ * Part 1: prepare quirk flag
+ */
+ if (altno == 2 && num == 3 &&
+ fp && fp->altsetting == 1 && fp->channels == 1 &&
+ fp->formats == SNDRV_PCM_FMTBIT_S16_LE &&
+ protocol == UAC_VERSION_1 &&
+ le16_to_cpu(get_endpoint(alts, 0)->wMaxPacketSize) ==
+ fp->maxpacksize * 2)
+ bm_quirk = 1;

- dev_err(&dev->dev,
- "%u:%d : bogus bTerminalLink %d\n",
- iface_no, altno, as->bTerminalLink);
- continue;
+ fp = snd_usb_get_audioformat_uac12(chip, alts, protocol,
+ iface_no, i, altno,
+ stream, bm_quirk);
+ break;
}
-
case UAC_VERSION_3: {
struct uac3_input_terminal_descriptor *input_term;
struct uac3_output_terminal_descriptor *output_term;
- struct uac3_as_header_descriptor *as;
struct uac3_cluster_header_descriptor *cluster;
struct uac3_hc_descriptor_header hc_header;
u16 cluster_id, wLength;
@@ -923,40 +1015,12 @@ int snd_usb_parse_audio_interface(struct snd_usb_audio *chip, int iface_no)
}

if (protocol == UAC_VERSION_1 || protocol == UAC_VERSION_2) {
- /* get format type */
- fmt = snd_usb_find_csint_desc(alts->extra,
- alts->extralen,
- NULL, UAC_FORMAT_TYPE);
- if (!fmt) {
- dev_err(&dev->dev,
- "%u:%d : no UAC_FORMAT_TYPE desc\n",
- iface_no, altno);
- continue;
- }
- if (((protocol == UAC_VERSION_1) && (fmt->bLength < 8))
- || ((protocol == UAC_VERSION_2) &&
- (fmt->bLength < 6))) {
- dev_err(&dev->dev,
- "%u:%d : invalid UAC_FORMAT_TYPE desc\n",
- iface_no, altno);
+ if (!fp)
continue;
- }
+ else if (IS_ERR(fp))
+ return PTR_ERR(fp);

- /*
- * Blue Microphones workaround: The last altsetting is
- * identical with the previous one, except for a larger
- * packet size, but is actually a mislabeled two-channel
- * setting; ignore it.
- */
- if (fmt->bNrChannels == 1 &&
- fmt->bSubframeSize == 2 &&
- altno == 2 && num == 3 &&
- fp && fp->altsetting == 1 && fp->channels == 1 &&
- fp->formats == SNDRV_PCM_FMTBIT_S16_LE &&
- protocol == UAC_VERSION_1 &&
- le16_to_cpu(get_endpoint(alts, 0)->wMaxPacketSize) ==
- fp->maxpacksize * 2)
- continue;
+ goto skip_uac3;
}

fp = audio_format_alloc_init(chip, alts, protocol, iface_no, i,
@@ -967,45 +1031,18 @@ int snd_usb_parse_audio_interface(struct snd_usb_audio *chip, int iface_no)
fp->attributes = parse_uac_endpoint_attributes(chip, alts,
protocol,
iface_no);
-
- /* some quirks for attributes here */
- snd_usb_audioformat_attributes_quirk(chip, fp, stream);
+ fp->chmap = chmap_v3;

/* ok, let's parse further... */
- if (protocol == UAC_VERSION_1 || protocol == UAC_VERSION_2) {
- if (snd_usb_parse_audio_format(chip, fp, format,
- fmt, stream) < 0) {
- kfree(fp->rate_table);
- kfree(fp);
- fp = NULL;
- continue;
- }
- } else {
- struct uac3_as_header_descriptor *as;
-
- as = snd_usb_find_csint_desc(alts->extra,
- alts->extralen,
- NULL, UAC_AS_GENERAL);
-
- if (snd_usb_parse_audio_format_v3(chip, fp, as,
- stream) < 0) {
- kfree(fp->rate_table);
- kfree(fp);
- fp = NULL;
- continue;
- }
+ if (snd_usb_parse_audio_format_v3(chip, fp, as,
+ stream) < 0) {
+ kfree(fp->rate_table);
+ kfree(fp);
+ fp = NULL;
+ continue;
}

- /* Create chmap */
- if (fp->channels != num_channels)
- chconfig = 0;
-
- if (protocol == UAC_VERSION_3)
- fp->chmap = chmap_v3;
- else
- fp->chmap = convert_chmap(fp->channels, chconfig,
- protocol);
-
+skip_uac3:
dev_dbg(&dev->dev, "%u:%d: add audio endpoint %#x\n", iface_no, altno, fp->endpoint);
err = snd_usb_add_audio_stream(chip, stream, fp);
if (err < 0) {
--
1.9.1
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