[PATCH 1/4] ALSA: usb: stream: refactor audio interface parsing

From: Ruslan Bilovol
Date: Fri Apr 13 2018 - 18:25:09 EST


Offload snd_usb_parse_audio_interface() function which
became quite long after adding UAC3 spec support.

Move class-specific parts to separate functions
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@xxxxxxxxx>
---
sound/usb/stream.c | 613 +++++++++++++++++++++++++++++------------------------
1 file changed, 334 insertions(+), 279 deletions(-)

diff --git a/sound/usb/stream.c b/sound/usb/stream.c
index 6a8f584..586d664 100644
--- a/sound/usb/stream.c
+++ b/sound/usb/stream.c
@@ -626,6 +626,319 @@ static int parse_uac_endpoint_attributes(struct snd_usb_audio *chip,
return NULL;
}

+static struct audioformat *
+snd_usb_get_audioformat_uac12(struct snd_usb_audio *chip,
+ struct usb_host_interface *alts,
+ int protocol, int iface_no,
+ 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 = kzalloc(sizeof(*fp), GFP_KERNEL);
+ if (!fp)
+ return ERR_PTR(-ENOMEM);
+
+ fp->iface = iface_no;
+ fp->altsetting = altno;
+ fp->endpoint = get_endpoint(alts, 0)->bEndpointAddress;
+ fp->ep_attr = get_endpoint(alts, 0)->bmAttributes;
+ fp->datainterval = snd_usb_parse_datainterval(chip, alts);
+ fp->protocol = protocol;
+ fp->maxpacksize = le16_to_cpu(get_endpoint(alts, 0)->wMaxPacketSize);
+ fp->channels = num_channels;
+ if (snd_usb_get_speed(dev) == USB_SPEED_HIGH)
+ fp->maxpacksize = (((fp->maxpacksize >> 11) & 3) + 1)
+ * (fp->maxpacksize & 0x7ff);
+ fp->attributes = parse_uac_endpoint_attributes(chip, alts,
+ protocol, iface_no);
+ fp->clock = clock;
+ INIT_LIST_HEAD(&fp->list);
+
+ /* 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;
+}
+
+static struct audioformat *
+snd_usb_get_audioformat_uac3(struct snd_usb_audio *chip,
+ struct usb_host_interface *alts,
+ int iface_no, int altno, int stream)
+{
+ struct usb_device *dev = chip->dev;
+ struct uac3_input_terminal_descriptor *input_term;
+ struct uac3_output_terminal_descriptor *output_term;
+ struct uac3_cluster_header_descriptor *cluster;
+ struct uac3_as_header_descriptor *as;
+ struct uac3_hc_descriptor_header hc_header;
+ struct snd_pcm_chmap_elem *chmap;
+ unsigned int num_channels;
+ struct audioformat *fp;
+ u16 cluster_id, wLength;
+ int clock = 0;
+ int err;
+
+ 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;
+ }
+
+ cluster_id = le16_to_cpu(as->wClusterDescrID);
+ if (!cluster_id) {
+ dev_err(&dev->dev,
+ "%u:%d : no cluster descriptor\n",
+ iface_no, altno);
+ return NULL;
+ }
+
+ /*
+ * Get number of channels and channel map through
+ * High Capability Cluster Descriptor
+ *
+ * First step: get High Capability header and
+ * read size of Cluster Descriptor
+ */
+ err = snd_usb_ctl_msg(chip->dev,
+ usb_rcvctrlpipe(chip->dev, 0),
+ UAC3_CS_REQ_HIGH_CAPABILITY_DESCRIPTOR,
+ USB_RECIP_INTERFACE | USB_TYPE_CLASS | USB_DIR_IN,
+ cluster_id,
+ snd_usb_ctrl_intf(chip),
+ &hc_header, sizeof(hc_header));
+ if (err < 0)
+ return ERR_PTR(err);
+ else if (err != sizeof(hc_header)) {
+ dev_err(&dev->dev,
+ "%u:%d : can't get High Capability descriptor\n",
+ iface_no, altno);
+ return ERR_PTR(-EIO);
+ }
+
+ /*
+ * Second step: allocate needed amount of memory
+ * and request Cluster Descriptor
+ */
+ wLength = le16_to_cpu(hc_header.wLength);
+ cluster = kzalloc(wLength, GFP_KERNEL);
+ if (!cluster)
+ return ERR_PTR(-ENOMEM);
+ err = snd_usb_ctl_msg(chip->dev,
+ usb_rcvctrlpipe(chip->dev, 0),
+ UAC3_CS_REQ_HIGH_CAPABILITY_DESCRIPTOR,
+ USB_RECIP_INTERFACE | USB_TYPE_CLASS | USB_DIR_IN,
+ cluster_id,
+ snd_usb_ctrl_intf(chip),
+ cluster, wLength);
+ if (err < 0) {
+ kfree(cluster);
+ return ERR_PTR(err);
+ } else if (err != wLength) {
+ dev_err(&dev->dev,
+ "%u:%d : can't get Cluster Descriptor\n",
+ iface_no, altno);
+ kfree(cluster);
+ return ERR_PTR(-EIO);
+ }
+
+ num_channels = cluster->bNrChannels;
+ chmap = convert_chmap_v3(cluster);
+ kfree(cluster);
+
+ /*
+ * 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;
+ 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:
+ fp = kzalloc(sizeof(*fp), GFP_KERNEL);
+ if (!fp)
+ return ERR_PTR(-ENOMEM);
+
+ fp->iface = iface_no;
+ fp->altsetting = altno;
+ fp->endpoint = get_endpoint(alts, 0)->bEndpointAddress;
+ fp->ep_attr = get_endpoint(alts, 0)->bmAttributes;
+ fp->datainterval = snd_usb_parse_datainterval(chip, alts);
+ fp->protocol = UAC_VERSION_3;
+ fp->maxpacksize = le16_to_cpu(get_endpoint(alts, 0)->wMaxPacketSize);
+ fp->channels = num_channels;
+ if (snd_usb_get_speed(dev) == USB_SPEED_HIGH)
+ fp->maxpacksize = (((fp->maxpacksize >> 11) & 3) + 1)
+ * (fp->maxpacksize & 0x7ff);
+ fp->attributes = parse_uac_endpoint_attributes(chip, alts,
+ UAC_VERSION_3,
+ iface_no);
+ fp->clock = clock;
+ fp->chmap = chmap;
+ INIT_LIST_HEAD(&fp->list);
+
+ /* ok, let's parse further... */
+ if (snd_usb_parse_audio_format_v3(chip, fp, as, stream) < 0) {
+ kfree(fp->rate_table);
+ kfree(fp);
+ return NULL;
+ }
+
+ return fp;
+}
+
int snd_usb_parse_audio_interface(struct snd_usb_audio *chip, int iface_no)
{
struct usb_device *dev;
@@ -633,13 +946,8 @@ int snd_usb_parse_audio_interface(struct snd_usb_audio *chip, int iface_no)
struct usb_host_interface *alts;
struct usb_interface_descriptor *altsd;
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;
+ int num, protocol;

dev = chip->dev;

@@ -688,303 +996,50 @@ 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;
- }
-
- 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;
- }
-
- dev_err(&dev->dev,
- "%u:%d : bogus bTerminalLink %d\n",
- iface_no, altno, as->bTerminalLink);
- continue;
- }
-
- 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;
-
- 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;
- }
-
- cluster_id = le16_to_cpu(as->wClusterDescrID);
- if (!cluster_id) {
- dev_err(&dev->dev,
- "%u:%d : no cluster descriptor\n",
- iface_no, altno);
- continue;
- }
-
- /*
- * Get number of channels and channel map through
- * High Capability Cluster Descriptor
- *
- * First step: get High Capability header and
- * read size of Cluster Descriptor
- */
- err = snd_usb_ctl_msg(chip->dev,
- usb_rcvctrlpipe(chip->dev, 0),
- UAC3_CS_REQ_HIGH_CAPABILITY_DESCRIPTOR,
- USB_RECIP_INTERFACE | USB_TYPE_CLASS | USB_DIR_IN,
- cluster_id,
- snd_usb_ctrl_intf(chip),
- &hc_header, sizeof(hc_header));
- if (err < 0)
- return err;
- else if (err != sizeof(hc_header)) {
- dev_err(&dev->dev,
- "%u:%d : can't get High Capability descriptor\n",
- iface_no, altno);
- return -EIO;
- }
-
- /*
- * Second step: allocate needed amount of memory
- * and request Cluster Descriptor
- */
- wLength = le16_to_cpu(hc_header.wLength);
- cluster = kzalloc(wLength, GFP_KERNEL);
- if (!cluster)
- return -ENOMEM;
- err = snd_usb_ctl_msg(chip->dev,
- usb_rcvctrlpipe(chip->dev, 0),
- UAC3_CS_REQ_HIGH_CAPABILITY_DESCRIPTOR,
- USB_RECIP_INTERFACE | USB_TYPE_CLASS | USB_DIR_IN,
- cluster_id,
- snd_usb_ctrl_intf(chip),
- cluster, wLength);
- if (err < 0) {
- kfree(cluster);
- return err;
- } else if (err != wLength) {
- dev_err(&dev->dev,
- "%u:%d : can't get Cluster Descriptor\n",
- iface_no, altno);
- kfree(cluster);
- return -EIO;
- }
-
- num_channels = cluster->bNrChannels;
- chmap_v3 = convert_chmap_v3(cluster);
-
- kfree(cluster);
-
- format = le64_to_cpu(as->bmFormats);
-
- /* 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;
- break;
- }
-
- output_term = snd_usb_find_output_terminal_descriptor(chip->ctrl_intf,
- as->bTerminalLink);
- if (output_term) {
- clock = output_term->bCSourceID;
- break;
- }
-
- dev_err(&dev->dev,
- "%u:%d : bogus bTerminalLink %d\n",
- iface_no, altno, as->bTerminalLink);
- continue;
- }
- }
-
- 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);
- continue;
- }
+ int bm_quirk = 0;

/*
* 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 (fmt->bNrChannels == 1 &&
- fmt->bSubframeSize == 2 &&
- altno == 2 && num == 3 &&
+ 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)
- continue;
+ bm_quirk = 1;
+
+ fp = snd_usb_get_audioformat_uac12(chip, alts, protocol,
+ iface_no, altno,
+ stream, bm_quirk);
+ break;
+ }
+ case UAC_VERSION_3:
+ fp = snd_usb_get_audioformat_uac3(chip, alts,
+ iface_no, altno, stream);
+ break;
}

- fp = kzalloc(sizeof(*fp), GFP_KERNEL);
if (!fp)
- return -ENOMEM;
+ continue;
+ else if (IS_ERR(fp))
+ return PTR_ERR(fp);

- fp->iface = iface_no;
- fp->altsetting = altno;
fp->altset_idx = i;
- fp->endpoint = get_endpoint(alts, 0)->bEndpointAddress;
- fp->ep_attr = get_endpoint(alts, 0)->bmAttributes;
- fp->datainterval = snd_usb_parse_datainterval(chip, alts);
- fp->protocol = protocol;
- fp->maxpacksize = le16_to_cpu(get_endpoint(alts, 0)->wMaxPacketSize);
- fp->channels = num_channels;
- if (snd_usb_get_speed(dev) == USB_SPEED_HIGH)
- fp->maxpacksize = (((fp->maxpacksize >> 11) & 3) + 1)
- * (fp->maxpacksize & 0x7ff);
- fp->attributes = parse_uac_endpoint_attributes(chip, alts, protocol, iface_no);
- fp->clock = clock;
- INIT_LIST_HEAD(&fp->list);
-
- /* some quirks for attributes here */
- snd_usb_audioformat_attributes_quirk(chip, fp, stream);
-
- /* 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;
- }
- }
-
- /* 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);

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);
--
1.9.1