v4.19.13 snapshot.
diff --git a/sound/usb/clock.c b/sound/usb/clock.c
new file mode 100644
index 0000000..db5e39d
--- /dev/null
+++ b/sound/usb/clock.c
@@ -0,0 +1,622 @@
+/*
+ *   Clock domain and sample rate management functions
+ *
+ *   This program is free software; you can redistribute it and/or modify
+ *   it under the terms of the GNU General Public License as published by
+ *   the Free Software Foundation; either version 2 of the License, or
+ *   (at your option) any later version.
+ *
+ *   This program is distributed in the hope that it will be useful,
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *   GNU General Public License for more details.
+ *
+ *   You should have received a copy of the GNU General Public License
+ *   along with this program; if not, write to the Free Software
+ *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
+ *
+ */
+
+#include <linux/bitops.h>
+#include <linux/init.h>
+#include <linux/string.h>
+#include <linux/usb.h>
+#include <linux/usb/audio.h>
+#include <linux/usb/audio-v2.h>
+#include <linux/usb/audio-v3.h>
+
+#include <sound/core.h>
+#include <sound/info.h>
+#include <sound/pcm.h>
+
+#include "usbaudio.h"
+#include "card.h"
+#include "helper.h"
+#include "clock.h"
+#include "quirks.h"
+
+static void *find_uac_clock_desc(struct usb_host_interface *iface, int id,
+				 bool (*validator)(void *, int), u8 type)
+{
+	void *cs = NULL;
+
+	while ((cs = snd_usb_find_csint_desc(iface->extra, iface->extralen,
+					     cs, type))) {
+		if (validator(cs, id))
+			return cs;
+	}
+
+	return NULL;
+}
+
+static bool validate_clock_source_v2(void *p, int id)
+{
+	struct uac_clock_source_descriptor *cs = p;
+	return cs->bLength == sizeof(*cs) && cs->bClockID == id;
+}
+
+static bool validate_clock_source_v3(void *p, int id)
+{
+	struct uac3_clock_source_descriptor *cs = p;
+	return cs->bLength == sizeof(*cs) && cs->bClockID == id;
+}
+
+static bool validate_clock_selector_v2(void *p, int id)
+{
+	struct uac_clock_selector_descriptor *cs = p;
+	return cs->bLength >= sizeof(*cs) && cs->bClockID == id &&
+		cs->bLength == 7 + cs->bNrInPins;
+}
+
+static bool validate_clock_selector_v3(void *p, int id)
+{
+	struct uac3_clock_selector_descriptor *cs = p;
+	return cs->bLength >= sizeof(*cs) && cs->bClockID == id &&
+		cs->bLength == 11 + cs->bNrInPins;
+}
+
+static bool validate_clock_multiplier_v2(void *p, int id)
+{
+	struct uac_clock_multiplier_descriptor *cs = p;
+	return cs->bLength == sizeof(*cs) && cs->bClockID == id;
+}
+
+static bool validate_clock_multiplier_v3(void *p, int id)
+{
+	struct uac3_clock_multiplier_descriptor *cs = p;
+	return cs->bLength == sizeof(*cs) && cs->bClockID == id;
+}
+
+#define DEFINE_FIND_HELPER(name, obj, validator, type)		\
+static obj *name(struct usb_host_interface *iface, int id)	\
+{								\
+	return find_uac_clock_desc(iface, id, validator, type);	\
+}
+
+DEFINE_FIND_HELPER(snd_usb_find_clock_source,
+		   struct uac_clock_source_descriptor,
+		   validate_clock_source_v2, UAC2_CLOCK_SOURCE);
+DEFINE_FIND_HELPER(snd_usb_find_clock_source_v3,
+		   struct uac3_clock_source_descriptor,
+		   validate_clock_source_v3, UAC3_CLOCK_SOURCE);
+
+DEFINE_FIND_HELPER(snd_usb_find_clock_selector,
+		   struct uac_clock_selector_descriptor,
+		   validate_clock_selector_v2, UAC2_CLOCK_SELECTOR);
+DEFINE_FIND_HELPER(snd_usb_find_clock_selector_v3,
+		   struct uac3_clock_selector_descriptor,
+		   validate_clock_selector_v3, UAC3_CLOCK_SELECTOR);
+
+DEFINE_FIND_HELPER(snd_usb_find_clock_multiplier,
+		   struct uac_clock_multiplier_descriptor,
+		   validate_clock_multiplier_v2, UAC2_CLOCK_MULTIPLIER);
+DEFINE_FIND_HELPER(snd_usb_find_clock_multiplier_v3,
+		   struct uac3_clock_multiplier_descriptor,
+		   validate_clock_multiplier_v3, UAC3_CLOCK_MULTIPLIER);
+
+static int uac_clock_selector_get_val(struct snd_usb_audio *chip, int selector_id)
+{
+	unsigned char buf;
+	int ret;
+
+	ret = snd_usb_ctl_msg(chip->dev, usb_rcvctrlpipe(chip->dev, 0),
+			      UAC2_CS_CUR,
+			      USB_RECIP_INTERFACE | USB_TYPE_CLASS | USB_DIR_IN,
+			      UAC2_CX_CLOCK_SELECTOR << 8,
+			      snd_usb_ctrl_intf(chip) | (selector_id << 8),
+			      &buf, sizeof(buf));
+
+	if (ret < 0)
+		return ret;
+
+	return buf;
+}
+
+static int uac_clock_selector_set_val(struct snd_usb_audio *chip, int selector_id,
+					unsigned char pin)
+{
+	int ret;
+
+	ret = snd_usb_ctl_msg(chip->dev, usb_sndctrlpipe(chip->dev, 0),
+			      UAC2_CS_CUR,
+			      USB_RECIP_INTERFACE | USB_TYPE_CLASS | USB_DIR_OUT,
+			      UAC2_CX_CLOCK_SELECTOR << 8,
+			      snd_usb_ctrl_intf(chip) | (selector_id << 8),
+			      &pin, sizeof(pin));
+	if (ret < 0)
+		return ret;
+
+	if (ret != sizeof(pin)) {
+		usb_audio_err(chip,
+			"setting selector (id %d) unexpected length %d\n",
+			selector_id, ret);
+		return -EINVAL;
+	}
+
+	ret = uac_clock_selector_get_val(chip, selector_id);
+	if (ret < 0)
+		return ret;
+
+	if (ret != pin) {
+		usb_audio_err(chip,
+			"setting selector (id %d) to %x failed (current: %d)\n",
+			selector_id, pin, ret);
+		return -EINVAL;
+	}
+
+	return ret;
+}
+
+static bool uac_clock_source_is_valid(struct snd_usb_audio *chip,
+				      int protocol,
+				      int source_id)
+{
+	int err;
+	unsigned char data;
+	struct usb_device *dev = chip->dev;
+	u32 bmControls;
+
+	if (protocol == UAC_VERSION_3) {
+		struct uac3_clock_source_descriptor *cs_desc =
+			snd_usb_find_clock_source_v3(chip->ctrl_intf, source_id);
+
+		if (!cs_desc)
+			return 0;
+		bmControls = le32_to_cpu(cs_desc->bmControls);
+	} else { /* UAC_VERSION_1/2 */
+		struct uac_clock_source_descriptor *cs_desc =
+			snd_usb_find_clock_source(chip->ctrl_intf, source_id);
+
+		if (!cs_desc)
+			return 0;
+		bmControls = cs_desc->bmControls;
+	}
+
+	/* If a clock source can't tell us whether it's valid, we assume it is */
+	if (!uac_v2v3_control_is_readable(bmControls,
+				      UAC2_CS_CONTROL_CLOCK_VALID))
+		return 1;
+
+	err = snd_usb_ctl_msg(dev, usb_rcvctrlpipe(dev, 0), UAC2_CS_CUR,
+			      USB_TYPE_CLASS | USB_RECIP_INTERFACE | USB_DIR_IN,
+			      UAC2_CS_CONTROL_CLOCK_VALID << 8,
+			      snd_usb_ctrl_intf(chip) | (source_id << 8),
+			      &data, sizeof(data));
+
+	if (err < 0) {
+		dev_warn(&dev->dev,
+			 "%s(): cannot get clock validity for id %d\n",
+			   __func__, source_id);
+		return 0;
+	}
+
+	return !!data;
+}
+
+static int __uac_clock_find_source(struct snd_usb_audio *chip, int entity_id,
+				   unsigned long *visited, bool validate)
+{
+	struct uac_clock_source_descriptor *source;
+	struct uac_clock_selector_descriptor *selector;
+	struct uac_clock_multiplier_descriptor *multiplier;
+
+	entity_id &= 0xff;
+
+	if (test_and_set_bit(entity_id, visited)) {
+		usb_audio_warn(chip,
+			 "%s(): recursive clock topology detected, id %d.\n",
+			 __func__, entity_id);
+		return -EINVAL;
+	}
+
+	/* first, see if the ID we're looking for is a clock source already */
+	source = snd_usb_find_clock_source(chip->ctrl_intf, entity_id);
+	if (source) {
+		entity_id = source->bClockID;
+		if (validate && !uac_clock_source_is_valid(chip, UAC_VERSION_2,
+								entity_id)) {
+			usb_audio_err(chip,
+				"clock source %d is not valid, cannot use\n",
+				entity_id);
+			return -ENXIO;
+		}
+		return entity_id;
+	}
+
+	selector = snd_usb_find_clock_selector(chip->ctrl_intf, entity_id);
+	if (selector) {
+		int ret, i, cur;
+
+		/* the entity ID we are looking for is a selector.
+		 * find out what it currently selects */
+		ret = uac_clock_selector_get_val(chip, selector->bClockID);
+		if (ret < 0)
+			return ret;
+
+		/* Selector values are one-based */
+
+		if (ret > selector->bNrInPins || ret < 1) {
+			usb_audio_err(chip,
+				"%s(): selector reported illegal value, id %d, ret %d\n",
+				__func__, selector->bClockID, ret);
+
+			return -EINVAL;
+		}
+
+		cur = ret;
+		ret = __uac_clock_find_source(chip, selector->baCSourceID[ret - 1],
+					       visited, validate);
+		if (!validate || ret > 0 || !chip->autoclock)
+			return ret;
+
+		/* The current clock source is invalid, try others. */
+		for (i = 1; i <= selector->bNrInPins; i++) {
+			int err;
+
+			if (i == cur)
+				continue;
+
+			ret = __uac_clock_find_source(chip, selector->baCSourceID[i - 1],
+				visited, true);
+			if (ret < 0)
+				continue;
+
+			err = uac_clock_selector_set_val(chip, entity_id, i);
+			if (err < 0)
+				continue;
+
+			usb_audio_info(chip,
+				 "found and selected valid clock source %d\n",
+				 ret);
+			return ret;
+		}
+
+		return -ENXIO;
+	}
+
+	/* FIXME: multipliers only act as pass-thru element for now */
+	multiplier = snd_usb_find_clock_multiplier(chip->ctrl_intf, entity_id);
+	if (multiplier)
+		return __uac_clock_find_source(chip, multiplier->bCSourceID,
+						visited, validate);
+
+	return -EINVAL;
+}
+
+static int __uac3_clock_find_source(struct snd_usb_audio *chip, int entity_id,
+				   unsigned long *visited, bool validate)
+{
+	struct uac3_clock_source_descriptor *source;
+	struct uac3_clock_selector_descriptor *selector;
+	struct uac3_clock_multiplier_descriptor *multiplier;
+
+	entity_id &= 0xff;
+
+	if (test_and_set_bit(entity_id, visited)) {
+		usb_audio_warn(chip,
+			 "%s(): recursive clock topology detected, id %d.\n",
+			 __func__, entity_id);
+		return -EINVAL;
+	}
+
+	/* first, see if the ID we're looking for is a clock source already */
+	source = snd_usb_find_clock_source_v3(chip->ctrl_intf, entity_id);
+	if (source) {
+		entity_id = source->bClockID;
+		if (validate && !uac_clock_source_is_valid(chip, UAC_VERSION_3,
+								entity_id)) {
+			usb_audio_err(chip,
+				"clock source %d is not valid, cannot use\n",
+				entity_id);
+			return -ENXIO;
+		}
+		return entity_id;
+	}
+
+	selector = snd_usb_find_clock_selector_v3(chip->ctrl_intf, entity_id);
+	if (selector) {
+		int ret, i, cur;
+
+		/* the entity ID we are looking for is a selector.
+		 * find out what it currently selects */
+		ret = uac_clock_selector_get_val(chip, selector->bClockID);
+		if (ret < 0)
+			return ret;
+
+		/* Selector values are one-based */
+
+		if (ret > selector->bNrInPins || ret < 1) {
+			usb_audio_err(chip,
+				"%s(): selector reported illegal value, id %d, ret %d\n",
+				__func__, selector->bClockID, ret);
+
+			return -EINVAL;
+		}
+
+		cur = ret;
+		ret = __uac3_clock_find_source(chip, selector->baCSourceID[ret - 1],
+					       visited, validate);
+		if (!validate || ret > 0 || !chip->autoclock)
+			return ret;
+
+		/* The current clock source is invalid, try others. */
+		for (i = 1; i <= selector->bNrInPins; i++) {
+			int err;
+
+			if (i == cur)
+				continue;
+
+			ret = __uac3_clock_find_source(chip, selector->baCSourceID[i - 1],
+				visited, true);
+			if (ret < 0)
+				continue;
+
+			err = uac_clock_selector_set_val(chip, entity_id, i);
+			if (err < 0)
+				continue;
+
+			usb_audio_info(chip,
+				 "found and selected valid clock source %d\n",
+				 ret);
+			return ret;
+		}
+
+		return -ENXIO;
+	}
+
+	/* FIXME: multipliers only act as pass-thru element for now */
+	multiplier = snd_usb_find_clock_multiplier_v3(chip->ctrl_intf,
+						      entity_id);
+	if (multiplier)
+		return __uac3_clock_find_source(chip, multiplier->bCSourceID,
+						visited, validate);
+
+	return -EINVAL;
+}
+
+/*
+ * For all kinds of sample rate settings and other device queries,
+ * the clock source (end-leaf) must be used. However, clock selectors,
+ * clock multipliers and sample rate converters may be specified as
+ * clock source input to terminal. This functions walks the clock path
+ * to its end and tries to find the source.
+ *
+ * The 'visited' bitfield is used internally to detect recursive loops.
+ *
+ * Returns the clock source UnitID (>=0) on success, or an error.
+ */
+int snd_usb_clock_find_source(struct snd_usb_audio *chip, int protocol,
+			      int entity_id, bool validate)
+{
+	DECLARE_BITMAP(visited, 256);
+	memset(visited, 0, sizeof(visited));
+
+	switch (protocol) {
+	case UAC_VERSION_2:
+		return __uac_clock_find_source(chip, entity_id, visited,
+					       validate);
+	case UAC_VERSION_3:
+		return __uac3_clock_find_source(chip, entity_id, visited,
+					       validate);
+	default:
+		return -EINVAL;
+	}
+}
+
+static int set_sample_rate_v1(struct snd_usb_audio *chip, int iface,
+			      struct usb_host_interface *alts,
+			      struct audioformat *fmt, int rate)
+{
+	struct usb_device *dev = chip->dev;
+	unsigned int ep;
+	unsigned char data[3];
+	int err, crate;
+
+	if (get_iface_desc(alts)->bNumEndpoints < 1)
+		return -EINVAL;
+	ep = get_endpoint(alts, 0)->bEndpointAddress;
+
+	/* if endpoint doesn't have sampling rate control, bail out */
+	if (!(fmt->attributes & UAC_EP_CS_ATTR_SAMPLE_RATE))
+		return 0;
+
+	data[0] = rate;
+	data[1] = rate >> 8;
+	data[2] = rate >> 16;
+	err = snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0), UAC_SET_CUR,
+			      USB_TYPE_CLASS | USB_RECIP_ENDPOINT | USB_DIR_OUT,
+			      UAC_EP_CS_ATTR_SAMPLE_RATE << 8, ep,
+			      data, sizeof(data));
+	if (err < 0) {
+		dev_err(&dev->dev, "%d:%d: cannot set freq %d to ep %#x\n",
+			iface, fmt->altsetting, rate, ep);
+		return err;
+	}
+
+	/* Don't check the sample rate for devices which we know don't
+	 * support reading */
+	if (snd_usb_get_sample_rate_quirk(chip))
+		return 0;
+	/* the firmware is likely buggy, don't repeat to fail too many times */
+	if (chip->sample_rate_read_error > 2)
+		return 0;
+
+	err = snd_usb_ctl_msg(dev, usb_rcvctrlpipe(dev, 0), UAC_GET_CUR,
+			      USB_TYPE_CLASS | USB_RECIP_ENDPOINT | USB_DIR_IN,
+			      UAC_EP_CS_ATTR_SAMPLE_RATE << 8, ep,
+			      data, sizeof(data));
+	if (err < 0) {
+		dev_err(&dev->dev, "%d:%d: cannot get freq at ep %#x\n",
+			iface, fmt->altsetting, ep);
+		chip->sample_rate_read_error++;
+		return 0; /* some devices don't support reading */
+	}
+
+	crate = data[0] | (data[1] << 8) | (data[2] << 16);
+	if (crate != rate) {
+		dev_warn(&dev->dev, "current rate %d is different from the runtime rate %d\n", crate, rate);
+		// runtime->rate = crate;
+	}
+
+	return 0;
+}
+
+static int get_sample_rate_v2v3(struct snd_usb_audio *chip, int iface,
+			      int altsetting, int clock)
+{
+	struct usb_device *dev = chip->dev;
+	__le32 data;
+	int err;
+
+	err = snd_usb_ctl_msg(dev, usb_rcvctrlpipe(dev, 0), UAC2_CS_CUR,
+			      USB_TYPE_CLASS | USB_RECIP_INTERFACE | USB_DIR_IN,
+			      UAC2_CS_CONTROL_SAM_FREQ << 8,
+			      snd_usb_ctrl_intf(chip) | (clock << 8),
+			      &data, sizeof(data));
+	if (err < 0) {
+		dev_warn(&dev->dev, "%d:%d: cannot get freq (v2/v3): err %d\n",
+			 iface, altsetting, err);
+		return 0;
+	}
+
+	return le32_to_cpu(data);
+}
+
+static int set_sample_rate_v2v3(struct snd_usb_audio *chip, int iface,
+			      struct usb_host_interface *alts,
+			      struct audioformat *fmt, int rate)
+{
+	struct usb_device *dev = chip->dev;
+	__le32 data;
+	int err, cur_rate, prev_rate;
+	int clock;
+	bool writeable;
+	u32 bmControls;
+
+	/* First, try to find a valid clock. This may trigger
+	 * automatic clock selection if the current clock is not
+	 * valid.
+	 */
+	clock = snd_usb_clock_find_source(chip, fmt->protocol,
+					  fmt->clock, true);
+	if (clock < 0) {
+		/* We did not find a valid clock, but that might be
+		 * because the current sample rate does not match an
+		 * external clock source. Try again without validation
+		 * and we will do another validation after setting the
+		 * rate.
+		 */
+		clock = snd_usb_clock_find_source(chip, fmt->protocol,
+						  fmt->clock, false);
+		if (clock < 0)
+			return clock;
+	}
+
+	prev_rate = get_sample_rate_v2v3(chip, iface, fmt->altsetting, clock);
+	if (prev_rate == rate)
+		goto validation;
+
+	if (fmt->protocol == UAC_VERSION_3) {
+		struct uac3_clock_source_descriptor *cs_desc;
+
+		cs_desc = snd_usb_find_clock_source_v3(chip->ctrl_intf, clock);
+		bmControls = le32_to_cpu(cs_desc->bmControls);
+	} else {
+		struct uac_clock_source_descriptor *cs_desc;
+
+		cs_desc = snd_usb_find_clock_source(chip->ctrl_intf, clock);
+		bmControls = cs_desc->bmControls;
+	}
+
+	writeable = uac_v2v3_control_is_writeable(bmControls,
+						  UAC2_CS_CONTROL_SAM_FREQ);
+	if (writeable) {
+		data = cpu_to_le32(rate);
+		err = snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0), UAC2_CS_CUR,
+				      USB_TYPE_CLASS | USB_RECIP_INTERFACE | USB_DIR_OUT,
+				      UAC2_CS_CONTROL_SAM_FREQ << 8,
+				      snd_usb_ctrl_intf(chip) | (clock << 8),
+				      &data, sizeof(data));
+		if (err < 0) {
+			usb_audio_err(chip,
+				"%d:%d: cannot set freq %d (v2/v3): err %d\n",
+				iface, fmt->altsetting, rate, err);
+			return err;
+		}
+
+		cur_rate = get_sample_rate_v2v3(chip, iface,
+						fmt->altsetting, clock);
+	} else {
+		cur_rate = prev_rate;
+	}
+
+	if (cur_rate != rate) {
+		if (!writeable) {
+			usb_audio_warn(chip,
+				 "%d:%d: freq mismatch (RO clock): req %d, clock runs @%d\n",
+				 iface, fmt->altsetting, rate, cur_rate);
+			return -ENXIO;
+		}
+		usb_audio_dbg(chip,
+			"current rate %d is different from the runtime rate %d\n",
+			cur_rate, rate);
+	}
+
+	/* Some devices doesn't respond to sample rate changes while the
+	 * interface is active. */
+	if (rate != prev_rate) {
+		usb_set_interface(dev, iface, 0);
+		snd_usb_set_interface_quirk(dev);
+		usb_set_interface(dev, iface, fmt->altsetting);
+		snd_usb_set_interface_quirk(dev);
+	}
+
+validation:
+	/* validate clock after rate change */
+	if (!uac_clock_source_is_valid(chip, fmt->protocol, clock))
+		return -ENXIO;
+	return 0;
+}
+
+int snd_usb_init_sample_rate(struct snd_usb_audio *chip, int iface,
+			     struct usb_host_interface *alts,
+			     struct audioformat *fmt, int rate)
+{
+	switch (fmt->protocol) {
+	case UAC_VERSION_1:
+	default:
+		return set_sample_rate_v1(chip, iface, alts, fmt, rate);
+
+	case UAC_VERSION_3:
+		if (chip->badd_profile >= UAC3_FUNCTION_SUBCLASS_GENERIC_IO) {
+			if (rate != UAC3_BADD_SAMPLING_RATE)
+				return -ENXIO;
+			else
+				return 0;
+		}
+	/* fall through */
+	case UAC_VERSION_2:
+		return set_sample_rate_v2v3(chip, iface, alts, fmt, rate);
+	}
+}
+