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From:   Ruslan Bilovol <ruslan.bilovol@gmail.com>
To:     Felipe Balbi <balbi@kernel.org>
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        linux-usb@vger.kernel.org, linux-doc@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: [PATCH 1/1] usb: gadget: add USB Audio Device Class 3.0 gadget support
Date:   Tue,  7 Nov 2017 03:52:02 +0200
Message-Id: <1510019522-15155-2-git-send-email-ruslan.bilovol@gmail.com>
In-Reply-To: <1510019522-15155-1-git-send-email-ruslan.bilovol@gmail.com>
References: <1510019522-15155-1-git-send-email-ruslan.bilovol@gmail.com>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

Recently released USB Audio Class 3.0 specification
introduces many significant changes comparing to
previous versions, like
 - new Power Domains, support for LPM/L1
 - new Cluster descriptor
 - changed layout of all class-specific descriptors
 - new High Capability descriptors
 - New class-specific String descriptors
 - new and removed units
 - additional sources for interrupts
 - removed Type II Audio Data Formats
 - ... and many other things (check spec)

It also provides backward compatibility through
multiple configurations, as well as requires
mandatory support for BADD (Basic Audio Device
Definition) on each ADC3.0 compliant device

This patch adds UAC3 gadget support basing on UAC3
specification, implementing Generic I/O Profile
(BAOF + BAIF) from BADD document.

There are still few areas for future improvements
because not all functionality is completely
implemented, for example volume, mute and
power management handling has dummy implementation
in some places

Signed-off-by: Ruslan Bilovol <ruslan.bilovol@gmail.com>
---
 Documentation/ABI/testing/configfs-usb-gadget-uac3 |   14 +
 Documentation/usb/gadget-testing.txt               |   41 +
 drivers/usb/gadget/Kconfig                         |   22 +
 drivers/usb/gadget/function/Makefile               |    2 +
 drivers/usb/gadget/function/f_uac3.c               | 1497 ++++++++++++++++++++
 drivers/usb/gadget/function/u_uac3.h               |   38 +
 drivers/usb/gadget/legacy/Kconfig                  |    3 +-
 7 files changed, 1616 insertions(+), 1 deletion(-)
 create mode 100644 Documentation/ABI/testing/configfs-usb-gadget-uac3
 create mode 100644 drivers/usb/gadget/function/f_uac3.c
 create mode 100644 drivers/usb/gadget/function/u_uac3.h

diff --git a/Documentation/ABI/testing/configfs-usb-gadget-uac3 b/Documentation/ABI/testing/configfs-usb-gadget-uac3
new file mode 100644
index 0000000..54bb00e
--- /dev/null
+++ b/Documentation/ABI/testing/configfs-usb-gadget-uac3
@@ -0,0 +1,14 @@
+What:		/config/usb-gadget/gadget/functions/uac3.name
+Date:		Nov 2017
+KernelVersion:	4.16
+Description:
+		The attributes:
+
+		c_chmask - capture channel mask
+		c_srate - capture sampling rate
+		c_ssize - capture sample size (bytes)
+		p_chmask - playback channel mask
+		p_srate - playback sampling rate
+		p_ssize - playback sample size (bytes)
+		req_number - the number of pre-allocated request
+			for both capture and playback
diff --git a/Documentation/usb/gadget-testing.txt b/Documentation/usb/gadget-testing.txt
index fbc397d..36d5e2b 100644
--- a/Documentation/usb/gadget-testing.txt
+++ b/Documentation/usb/gadget-testing.txt
@@ -21,6 +21,7 @@ provided by gadgets.
 18. UVC function
 19. PRINTER function
 20. UAC1 function (new API)
+21. UAC3 function
 
 
 1. ACM function
@@ -817,3 +818,43 @@ e.g.:
 
 $ arecord -f dat -t wav -D hw:CARD=UAC1Gadget,DEV=0 | \
 aplay -D default:CARD=OdroidU3
+
+21. UAC3 function
+=================
+
+The function is provided by usb_f_uac3.ko module.
+
+Function-specific configfs interface
+------------------------------------
+
+The function name to use when creating the function directory is "uac3".
+The uac3 function provides these attributes in its function directory:
+
+	c_chmask - capture channel mask
+	c_srate - capture sampling rate
+	c_ssize - capture sample size (bytes)
+	p_chmask - playback channel mask
+	p_srate - playback sampling rate
+	p_ssize - playback sample size (bytes)
+	req_number - the number of pre-allocated request for both capture
+		     and playback
+
+The attributes have sane default values.
+
+Testing the UAC3 function
+-------------------------
+
+device: run the gadget
+host: aplay -l # should list our USB Audio Gadget
+
+This function does not require real hardware support, it just
+sends a stream of audio data to/from the host. In order to
+actually hear something at the device side, a command similar
+to this must be used at the device side:
+
+$ arecord -f dat -t wav -D hw:2,0 | aplay -D hw:0,0 &
+
+e.g.:
+
+$ arecord -f dat -t wav -D hw:CARD=UAC3Gadget,DEV=0 | \
+aplay -D default:CARD=OdroidU3
diff --git a/drivers/usb/gadget/Kconfig b/drivers/usb/gadget/Kconfig
index 31cce78..d53ae7d 100644
--- a/drivers/usb/gadget/Kconfig
+++ b/drivers/usb/gadget/Kconfig
@@ -200,6 +200,9 @@ config USB_F_UAC1_LEGACY
 config USB_F_UAC2
 	tristate
 
+config USB_F_UAC3
+	tristate
+
 config USB_F_UVC
 	tristate
 
@@ -418,6 +421,25 @@ config USB_CONFIGFS_F_UAC2
 	  received from the USB Host and choose to provide whatever it
 	  wants as audio data to the USB Host.
 
+config USB_CONFIGFS_F_UAC3
+	bool "Audio Class 3.0"
+	depends on USB_CONFIGFS
+	depends on SND
+	select USB_LIBCOMPOSITE
+	select SND_PCM
+	select USB_U_AUDIO
+	select USB_F_UAC3
+	help
+	  This Audio function is compatible with USB Audio Class
+	  specification 3.0. It implements 1 AudioControl interface,
+	  1 AudioStreaming Interface each for USB-OUT and USB-IN.
+	  This driver doesn't expect any real Audio codec to be present
+	  on the device - the audio streams are simply sinked to and
+	  sourced from a virtual ALSA sound card created. The user-space
+	  application may choose to do whatever it wants with the data
+	  received from the USB Host and choose to provide whatever it
+	  wants as audio data to the USB Host.
+
 config USB_CONFIGFS_F_MIDI
 	bool "MIDI function"
 	depends on USB_CONFIGFS
diff --git a/drivers/usb/gadget/function/Makefile b/drivers/usb/gadget/function/Makefile
index 86e8252..6a77eca 100644
--- a/drivers/usb/gadget/function/Makefile
+++ b/drivers/usb/gadget/function/Makefile
@@ -39,6 +39,8 @@ usb_f_uac1_legacy-y		:= f_uac1_legacy.o u_uac1_legacy.o
 obj-$(CONFIG_USB_F_UAC1_LEGACY)	+= usb_f_uac1_legacy.o
 usb_f_uac2-y			:= f_uac2.o
 obj-$(CONFIG_USB_F_UAC2)	+= usb_f_uac2.o
+usb_f_uac3-y			:= f_uac3.o
+obj-$(CONFIG_USB_F_UAC3)	+= usb_f_uac3.o
 usb_f_uvc-y			:= f_uvc.o uvc_queue.o uvc_v4l2.o uvc_video.o uvc_configfs.o
 obj-$(CONFIG_USB_F_UVC)		+= usb_f_uvc.o
 usb_f_midi-y			:= f_midi.o
diff --git a/drivers/usb/gadget/function/f_uac3.c b/drivers/usb/gadget/function/f_uac3.c
new file mode 100644
index 0000000..4dee0a5
--- /dev/null
+++ b/drivers/usb/gadget/function/f_uac3.c
@@ -0,0 +1,1497 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * f_uac3.c -- USB Audio Class 3.0 Function
+ *
+ * Copyright (C) 2017 Ruslan Bilovol <ruslan.bilovol@gmail.com>
+ */
+
+#include <linux/usb/audio.h>
+#include <linux/usb/audio-v2.h>
+#include <linux/usb/audio-v3.h>
+#include <linux/module.h>
+
+#include "u_audio.h"
+#include "u_uac3.h"
+
+/*
+ * The driver implements Generic I/O Profile (BAOF + BAIF)
+ * from BasicAudioDevice3.0 spec:
+ *    USB-OUT -> IT_1 -> FU_2 -> OT_3 -> ALSA Capture
+ *    ALSA Playback -> IT_4 -> FU_5 -> OT_6 -> USB-IN
+ *
+ * Capture and Playback belong to independent Power Domains
+ * PD_10 and PD_11 respectively.
+ *
+ * Capture and Playback sampling rates are independently
+ * controlled by two clock sources:
+ *    CLK_9 := c_srate, and CLK_12 := p_srate
+ *
+ * Entity IDs are taken from BasicAudioDevice3.0 spec.
+ * The only difference is in additional playback clock
+ * source which is required for independent sampling rate
+ * of Capture and Playback channels.
+ */
+
+#define USB_OUT_IT_ID	1
+#define USB_OUT_FU_ID	2
+#define IO_OUT_OT_ID	3
+#define IO_IN_IT_ID	4
+#define USB_IN_FU_ID	5
+#define USB_IN_OT_ID	6
+
+#define USB_OUT_CLK_ID	9
+#define USB_IN_CLK_ID	12
+
+#define USB_OUT_PD_ID	10
+#define USB_IN_PD_ID	11
+
+#define CONTROL_ABSENT	0
+#define CONTROL_RDONLY	1
+#define CONTROL_RDWR	3
+
+#define CLK_FREQ_CTRL	0
+#define CLK_VLD_CTRL	2
+
+#define INSRT_CTRL	0
+#define OVRLD_CTRL	2
+#define UNFLW_CTRL	4
+#define OVFLW_CTRL	6
+
+struct uac3_hc_desc {
+	struct uac3_hc_descriptor_header	*hc_header;
+	struct list_head			list;
+};
+
+struct f_uac3 {
+	struct g_audio g_audio;
+
+	/* High Capacity descriptors */
+	struct list_head hc_desc_list;
+
+	u8 ac_intf, as_in_intf, as_out_intf;
+	u8 ac_alt, as_in_alt, as_out_alt;	/* needed for get_alt() */
+};
+
+static inline struct f_uac3 *func_to_uac3(struct usb_function *f)
+{
+	return container_of(f, struct f_uac3, g_audio.func);
+}
+
+static inline struct f_uac3_opts *g_audio_to_uac3_opts(struct g_audio *audio)
+{
+	return container_of(audio->func.fi, struct f_uac3_opts, func_inst);
+}
+
+/* --------- USB Function Interface ------------- */
+enum {
+	STR_ASSOC,
+	STR_IF_CTRL,
+	STR_AS_OUT_ALT0,
+	STR_AS_OUT_ALT1,
+	STR_AS_IN_ALT0,
+	STR_AS_IN_ALT1,
+};
+
+static struct usb_string strings_fn[] = {
+	[STR_ASSOC].s = "Source/Sink",
+	[STR_IF_CTRL].s = "Topology Control",
+	[STR_AS_OUT_ALT0].s = "Playback Inactive",
+	[STR_AS_OUT_ALT1].s = "Playback Active",
+	[STR_AS_IN_ALT0].s = "Capture Inactive",
+	[STR_AS_IN_ALT1].s = "Capture Active",
+	{ },
+};
+
+static struct usb_gadget_strings str_fn = {
+	.language = 0x0409,	/* en-us */
+	.strings = strings_fn,
+};
+
+static struct usb_gadget_strings *fn_strings[] = {
+	&str_fn,
+	NULL,
+};
+
+static struct usb_interface_assoc_descriptor iad_desc = {
+	.bLength = sizeof iad_desc,
+	.bDescriptorType = USB_DT_INTERFACE_ASSOCIATION,
+
+	.bFirstInterface = 0,
+	.bInterfaceCount = 3,
+	.bFunctionClass = USB_CLASS_AUDIO,
+	.bFunctionSubClass = UAC3_FUNCTION_SUBCLASS_GENERIC_IO,
+	.bFunctionProtocol = UAC_VERSION_3,
+};
+
+/* Audio Control Interface */
+static struct usb_interface_descriptor std_ac_if_desc = {
+	.bLength = sizeof std_ac_if_desc,
+	.bDescriptorType = USB_DT_INTERFACE,
+
+	.bAlternateSetting = 0,
+	.bNumEndpoints = 0,
+	.bInterfaceClass = USB_CLASS_AUDIO,
+	.bInterfaceSubClass = USB_SUBCLASS_AUDIOCONTROL,
+	.bInterfaceProtocol = UAC_VERSION_3,
+};
+
+/* Clock source for IN traffic */
+static struct uac3_clock_source_descriptor in_clk_src_desc = {
+	.bLength = sizeof in_clk_src_desc,
+	.bDescriptorType = USB_DT_CS_INTERFACE,
+
+	.bDescriptorSubtype = UAC3_CLOCK_SOURCE,
+	.bClockID = USB_IN_CLK_ID,
+	.bmAttributes = UAC3_CLOCK_SOURCE_TYPE_INT,
+	.bmControls = cpu_to_le32(CONTROL_RDONLY << CLK_FREQ_CTRL),
+	.bReferenceTerminal = 0,
+	.wClockSourceStr = 0, /* Not used */
+};
+
+/* Clock source for OUT traffic */
+static struct uac3_clock_source_descriptor out_clk_src_desc = {
+	.bLength = sizeof out_clk_src_desc,
+	.bDescriptorType = USB_DT_CS_INTERFACE,
+
+	.bDescriptorSubtype = UAC3_CLOCK_SOURCE,
+	.bClockID = USB_OUT_CLK_ID,
+	.bmAttributes = UAC3_CLOCK_SOURCE_TYPE_INT,
+	.bmControls = cpu_to_le32(CONTROL_RDONLY << CLK_FREQ_CTRL),
+	.bReferenceTerminal = 0,
+	.wClockSourceStr = 0, /* Not used */
+};
+
+/* Input Terminal for USB_OUT */
+static struct uac3_input_terminal_descriptor usb_out_it_desc = {
+	.bLength = sizeof usb_out_it_desc,
+	.bDescriptorType = USB_DT_CS_INTERFACE,
+
+	.bDescriptorSubtype = UAC_INPUT_TERMINAL,
+	.bTerminalID = USB_OUT_IT_ID,
+	.wTerminalType = cpu_to_le16(UAC_TERMINAL_STREAMING),
+	.bAssocTerminal = 0,
+	.bCSourceID = USB_OUT_CLK_ID,
+	.bmControls = 0,
+	.wClusterDescrID = 0, /* := dynamic */
+	.wExTerminalDescrID = 0,
+	.wConnectorsDescrID = 0,
+	.wTerminalDescrStr = 0, /* Not used */
+};
+
+/* Output Terminal for I/O-Out */
+static struct uac3_output_terminal_descriptor io_out_ot_desc = {
+	.bLength = sizeof io_out_ot_desc,
+	.bDescriptorType = USB_DT_CS_INTERFACE,
+
+	.bDescriptorSubtype = UAC_OUTPUT_TERMINAL,
+	.bTerminalID = IO_OUT_OT_ID,
+	.wTerminalType = cpu_to_le16(UAC_OUTPUT_TERMINAL_UNDEFINED),
+	.bAssocTerminal = 0,
+	.bSourceID = USB_OUT_FU_ID,
+	.bCSourceID = USB_OUT_CLK_ID,
+	.bmControls = 0,
+	.wExTerminalDescrID = 0,
+	.wConnectorsDescrID = 0,
+	.wTerminalDescrStr = 0, /* Not used */
+};
+
+/* Input Terminal for I/O-In */
+static struct uac3_input_terminal_descriptor io_in_it_desc = {
+	.bLength = sizeof io_in_it_desc,
+	.bDescriptorType = USB_DT_CS_INTERFACE,
+
+	.bDescriptorSubtype = UAC_INPUT_TERMINAL,
+	.bTerminalID = IO_IN_IT_ID,
+	.wTerminalType = cpu_to_le16(UAC_INPUT_TERMINAL_UNDEFINED),
+	.bAssocTerminal = 0,
+	.bCSourceID = USB_IN_CLK_ID,
+	.bmControls = 0,
+	.wClusterDescrID = 0, /* := dynamic */
+	.wExTerminalDescrID = 0,
+	.wConnectorsDescrID = 0,
+	.wTerminalDescrStr = 0, /* Not used */
+};
+
+/* Output Terminal for USB_IN */
+static struct uac3_output_terminal_descriptor usb_in_ot_desc = {
+	.bLength = sizeof usb_in_ot_desc,
+	.bDescriptorType = USB_DT_CS_INTERFACE,
+
+	.bDescriptorSubtype = UAC_OUTPUT_TERMINAL,
+	.bTerminalID = USB_IN_OT_ID,
+	.wTerminalType = cpu_to_le16(UAC_TERMINAL_STREAMING),
+	.bAssocTerminal = 0,
+	.bSourceID = USB_IN_FU_ID,
+	.bCSourceID = USB_IN_CLK_ID,
+	.bmControls = 0,
+	.wExTerminalDescrID = 0,
+	.wConnectorsDescrID = 0,
+	.wTerminalDescrStr = 0, /* Not used */
+};
+
+/* Feature Units - dynamically allocated */
+static struct uac3_feature_unit_descriptor *usb_out_fu_desc;
+static struct uac3_feature_unit_descriptor *usb_in_fu_desc;
+
+DECLARE_UAC3_POWER_DOMAIN_DESCRIPTOR(2);
+
+/* Time to recover from D1 to D0. 30 us, expressed in 50 us increments */
+#define BADP_RECOVERY_TIME_D1D0		0x0258
+/* Time to recover from D2 to D0. 300 ms, expressed in 50 us increments. */
+#define BADP_RECOVERY_TIME_D2D0		0x1770
+
+static struct uac3_power_domain_descriptor_2 usb_out_pd_desc = {
+	.bLength = sizeof usb_out_pd_desc,
+	.bDescriptorType = USB_DT_CS_INTERFACE,
+
+	.bDescriptorSubtype = UAC3_POWER_DOMAIN,
+	.bPowerDomainID = USB_OUT_PD_ID,
+	.waRecoveryTime1 = cpu_to_le16(BADP_RECOVERY_TIME_D1D0),
+	.waRecoveryTime2 = cpu_to_le16(BADP_RECOVERY_TIME_D2D0),
+	.bNrEntities = 2,
+	.baEntityID[0] = USB_OUT_IT_ID,
+	.baEntityID[1] = IO_OUT_OT_ID,
+	.wPDomainDescrStr = 0,	/* Not used */
+};
+
+static struct uac3_power_domain_descriptor_2 usb_in_pd_desc = {
+	.bLength = sizeof usb_out_pd_desc,
+	.bDescriptorType = USB_DT_CS_INTERFACE,
+
+	.bDescriptorSubtype = UAC3_POWER_DOMAIN,
+	.bPowerDomainID = USB_IN_PD_ID,
+	.waRecoveryTime1 = cpu_to_le16(BADP_RECOVERY_TIME_D1D0),
+	.waRecoveryTime2 = cpu_to_le16(BADP_RECOVERY_TIME_D2D0),
+	.bNrEntities = 2,
+	.baEntityID[0] = IO_IN_IT_ID,
+	.baEntityID[1] = USB_IN_OT_ID,
+	.wPDomainDescrStr = 0,	/* Not used */
+};
+
+static struct uac3_ac_header_descriptor ac_hdr_desc = {
+	.bLength = sizeof ac_hdr_desc,
+	.bDescriptorType = USB_DT_CS_INTERFACE,
+
+	.bDescriptorSubtype = UAC_MS_HEADER,
+	.bCategory = UAC3_FUNCTION_IO_BOX,
+	/* .wTotalLength := DYNAMIC */
+	.bmControls = 0,
+};
+
+/* Audio Streaming OUT Interface - Alt0 */
+static struct usb_interface_descriptor std_as_out_if0_desc = {
+	.bLength = sizeof std_as_out_if0_desc,
+	.bDescriptorType = USB_DT_INTERFACE,
+
+	.bAlternateSetting = 0,
+	.bNumEndpoints = 0,
+	.bInterfaceClass = USB_CLASS_AUDIO,
+	.bInterfaceSubClass = USB_SUBCLASS_AUDIOSTREAMING,
+	.bInterfaceProtocol = UAC_VERSION_3,
+};
+
+/* Audio Streaming OUT Interface - Alt1 */
+static struct usb_interface_descriptor std_as_out_if1_desc = {
+	.bLength = sizeof std_as_out_if1_desc,
+	.bDescriptorType = USB_DT_INTERFACE,
+
+	.bAlternateSetting = 1,
+	.bNumEndpoints = 1,
+	.bInterfaceClass = USB_CLASS_AUDIO,
+	.bInterfaceSubClass = USB_SUBCLASS_AUDIOSTREAMING,
+	.bInterfaceProtocol = UAC_VERSION_3,
+};
+
+/* Audio Stream OUT Intface Desc */
+static struct uac3_as_header_descriptor as_out_hdr_desc = {
+	.bLength = sizeof as_out_hdr_desc,
+	.bDescriptorType = USB_DT_CS_INTERFACE,
+
+	.bDescriptorSubtype = UAC_AS_GENERAL,
+	.bTerminalLink = USB_OUT_IT_ID,
+	.bmControls = 0,
+	.wClusterDescrID = 0,
+	.bmFormats = cpu_to_le64(UAC_FORMAT_TYPE_I_PCM),
+	/* .bSubslotSize = DYNAMIC */
+	/* .bBitResolution = DYNAMIC */
+	.bmAuxProtocols = 0,
+	.bControlSize = 0,
+};
+
+/* STD AS ISO OUT Endpoint */
+static struct usb_endpoint_descriptor fs_epout_desc = {
+	.bLength = USB_DT_ENDPOINT_SIZE,
+	.bDescriptorType = USB_DT_ENDPOINT,
+
+	.bEndpointAddress = USB_DIR_OUT,
+	.bmAttributes = USB_ENDPOINT_XFER_ISOC | USB_ENDPOINT_SYNC_ASYNC,
+	.wMaxPacketSize = cpu_to_le16(1023),
+	.bInterval = 1,
+};
+
+static struct usb_endpoint_descriptor hs_epout_desc = {
+	.bLength = USB_DT_ENDPOINT_SIZE,
+	.bDescriptorType = USB_DT_ENDPOINT,
+
+	.bmAttributes = USB_ENDPOINT_XFER_ISOC | USB_ENDPOINT_SYNC_ASYNC,
+	.wMaxPacketSize = cpu_to_le16(1024),
+	.bInterval = 4,
+};
+
+/* CS AS ISO OUT Endpoint */
+static struct uac3_iso_endpoint_descriptor as_iso_out_desc = {
+	.bLength = sizeof as_iso_out_desc,
+	.bDescriptorType = USB_DT_CS_ENDPOINT,
+
+	.bDescriptorSubtype = UAC_EP_GENERAL,
+	.bmControls = 0,
+	.bLockDelayUnits = 0,
+	.wLockDelay = 0,
+};
+
+/* Audio Streaming IN Interface - Alt0 */
+static struct usb_interface_descriptor std_as_in_if0_desc = {
+	.bLength = sizeof std_as_in_if0_desc,
+	.bDescriptorType = USB_DT_INTERFACE,
+
+	.bAlternateSetting = 0,
+	.bNumEndpoints = 0,
+	.bInterfaceClass = USB_CLASS_AUDIO,
+	.bInterfaceSubClass = USB_SUBCLASS_AUDIOSTREAMING,
+	.bInterfaceProtocol = UAC_VERSION_3,
+};
+
+/* Audio Streaming IN Interface - Alt1 */
+static struct usb_interface_descriptor std_as_in_if1_desc = {
+	.bLength = sizeof std_as_in_if1_desc,
+	.bDescriptorType = USB_DT_INTERFACE,
+
+	.bAlternateSetting = 1,
+	.bNumEndpoints = 1,
+	.bInterfaceClass = USB_CLASS_AUDIO,
+	.bInterfaceSubClass = USB_SUBCLASS_AUDIOSTREAMING,
+	.bInterfaceProtocol = UAC_VERSION_3,
+};
+
+/* Audio Stream IN Intface Desc */
+static struct uac3_as_header_descriptor as_in_hdr_desc = {
+	.bLength = sizeof as_in_hdr_desc,
+	.bDescriptorType = USB_DT_CS_INTERFACE,
+
+	.bDescriptorSubtype = UAC_AS_GENERAL,
+	.bTerminalLink = USB_IN_OT_ID,
+	.bmControls = 0,
+	.wClusterDescrID = 0,
+	.bmFormats = cpu_to_le64(UAC_FORMAT_TYPE_I_PCM),
+	/* .bSubslotSize = DYNAMIC */
+	/* .bBitResolution = DYNAMIC */
+	.bmAuxProtocols = 0,
+	.bControlSize = 0,
+};
+
+/* STD AS ISO IN Endpoint */
+static struct usb_endpoint_descriptor fs_epin_desc = {
+	.bLength = USB_DT_ENDPOINT_SIZE,
+	.bDescriptorType = USB_DT_ENDPOINT,
+
+	.bEndpointAddress = USB_DIR_IN,
+	.bmAttributes = USB_ENDPOINT_XFER_ISOC | USB_ENDPOINT_SYNC_ASYNC,
+	.wMaxPacketSize = cpu_to_le16(1023),
+	.bInterval = 1,
+};
+
+static struct usb_endpoint_descriptor hs_epin_desc = {
+	.bLength = USB_DT_ENDPOINT_SIZE,
+	.bDescriptorType = USB_DT_ENDPOINT,
+
+	.bmAttributes = USB_ENDPOINT_XFER_ISOC | USB_ENDPOINT_SYNC_ASYNC,
+	.wMaxPacketSize = cpu_to_le16(1024),
+	.bInterval = 4,
+};
+
+/* CS AS ISO IN Endpoint */
+static struct uac3_iso_endpoint_descriptor as_iso_in_desc = {
+	.bLength = sizeof as_iso_in_desc,
+	.bDescriptorType = USB_DT_CS_ENDPOINT,
+
+	.bDescriptorSubtype = UAC_EP_GENERAL,
+	.bmControls = 0,
+	.bLockDelayUnits = 0,
+	.wLockDelay = 0,
+};
+
+static struct usb_descriptor_header *fs_ac_audio_desc[] = {
+	(struct usb_descriptor_header *)&iad_desc,
+	(struct usb_descriptor_header *)&std_ac_if_desc,
+
+	(struct usb_descriptor_header *)&ac_hdr_desc,
+	(struct usb_descriptor_header *)&in_clk_src_desc,
+	(struct usb_descriptor_header *)&out_clk_src_desc,
+	(struct usb_descriptor_header *)&usb_out_it_desc,
+	(struct usb_descriptor_header *)&io_in_it_desc,
+	(struct usb_descriptor_header *)&usb_in_ot_desc,
+	(struct usb_descriptor_header *)&io_out_ot_desc,
+	(struct usb_descriptor_header *)&usb_in_pd_desc,
+	(struct usb_descriptor_header *)&usb_out_pd_desc,
+	NULL,
+};
+
+static struct usb_descriptor_header *fs_as_audio_desc[] = {
+	(struct usb_descriptor_header *)&std_as_out_if0_desc,
+	(struct usb_descriptor_header *)&std_as_out_if1_desc,
+
+	(struct usb_descriptor_header *)&as_out_hdr_desc,
+	(struct usb_descriptor_header *)&fs_epout_desc,
+	(struct usb_descriptor_header *)&as_iso_out_desc,
+
+	(struct usb_descriptor_header *)&std_as_in_if0_desc,
+	(struct usb_descriptor_header *)&std_as_in_if1_desc,
+
+	(struct usb_descriptor_header *)&as_in_hdr_desc,
+	(struct usb_descriptor_header *)&fs_epin_desc,
+	(struct usb_descriptor_header *)&as_iso_in_desc,
+	NULL,
+};
+
+static struct usb_descriptor_header *hs_as_audio_desc[] = {
+	(struct usb_descriptor_header *)&std_as_out_if0_desc,
+	(struct usb_descriptor_header *)&std_as_out_if1_desc,
+
+	(struct usb_descriptor_header *)&as_out_hdr_desc,
+	(struct usb_descriptor_header *)&hs_epout_desc,
+	(struct usb_descriptor_header *)&as_iso_out_desc,
+
+	(struct usb_descriptor_header *)&std_as_in_if0_desc,
+	(struct usb_descriptor_header *)&std_as_in_if1_desc,
+
+	(struct usb_descriptor_header *)&as_in_hdr_desc,
+	(struct usb_descriptor_header *)&hs_epin_desc,
+	(struct usb_descriptor_header *)&as_iso_in_desc,
+	NULL,
+};
+
+struct cntrl_cur_lay2 {
+	__le16	wCUR;
+};
+
+struct cntrl_range_lay2 {
+	__le16	wNumSubRanges;
+	__le16	wMIN;
+	__le16	wMAX;
+	__le16	wRES;
+} __packed;
+
+struct cntrl_cur_lay3 {
+	__le32	dCUR;
+};
+
+struct cntrl_range_lay3 {
+	__le16	wNumSubRanges;
+	__le32	dMIN;
+	__le32	dMAX;
+	__le32	dRES;
+} __packed;
+
+/*
+ * Cluster descriptor we build here:
+ *  +---------------------------------------+
+ *  | Header                                |
+ *  +---------------------------------------+
+ *  |                 | Information segment |
+ *  | Channel 1 block +---------------------+
+ *  |                 | End segment         |
+ *  +---------------------------------------+
+ *  |                 ...                   |
+ *  +---------------------------------------+
+ *  |                 | Information segment |
+ *  | Channel n block +---------------------+
+ *  |                 | End segment         |
+ *  +---------------------------------------+
+ *
+ *  FIXME: only mono and stereo channels supported at this time
+ */
+static void *build_cluster_descriptor(const struct f_uac3_opts *uac3_opts,
+		bool is_playback)
+{
+	struct uac3_cluster_header_descriptor *cluster_desc;
+	int i, chmask, nr_channels;
+	u16 desc_size;
+	void *p;
+
+	if (is_playback)
+		chmask = uac3_opts->p_chmask;
+	else
+		chmask = uac3_opts->c_chmask;
+
+	nr_channels = num_channels(chmask);
+
+	if (!nr_channels) {
+		pr_err("f_uac3: no channels\n");
+		return NULL;
+	}
+
+	if (chmask & ~(0x3)) {
+		pr_err("f_uac3: only mono/stereo channels supported\n");
+		return NULL;
+	}
+
+	desc_size = sizeof(struct uac3_cluster_header_descriptor) +
+		nr_channels *
+		(sizeof(struct uac3_cluster_information_segment_descriptor) +
+			sizeof(struct uac3_cluster_end_segment_descriptor));
+
+	cluster_desc = kzalloc(desc_size, GFP_KERNEL);
+	if (!cluster_desc)
+		return NULL;
+
+	cluster_desc->wLength = cpu_to_le16(desc_size);
+	cluster_desc->bDescriptorType = UAC3_CS_CLUSTER;
+	cluster_desc->bDescriptorSubtype = UAC3_SEGMENT_UNDEFINED;
+	cluster_desc->bNrChannels = nr_channels;
+
+	p = cluster_desc;
+	p += sizeof(struct uac3_cluster_header_descriptor);
+	for (i = 0; i < nr_channels; i++) {
+		struct uac3_cluster_information_segment_descriptor *is_desc;
+		struct uac3_cluster_end_segment_descriptor *es_desc;
+		u8 ch_relationship;
+
+		is_desc = p;
+		is_desc->wLength = cpu_to_le16(sizeof(*is_desc));
+		is_desc->bSegmentType = UAC3_CHANNEL_INFORMATION;
+		is_desc->bChPurpose = UAC3_PURPOSE_GENERIC_AUDIO;
+
+		switch (nr_channels) {
+		case 1:
+		default:
+			ch_relationship = UAC3_CH_MONO;
+			break;
+		case 2:
+			if (chmask & 1)
+				ch_relationship = UAC3_CH_LEFT;
+			else
+				ch_relationship = UAC3_CH_RIGHT;
+			break;
+		}
+
+		is_desc->bChRelationship = ch_relationship;
+		is_desc->bChGroupID = 0;
+
+		p += sizeof(struct uac3_cluster_information_segment_descriptor);
+		es_desc = p;
+		es_desc->wLength = cpu_to_le16(sizeof(*es_desc));
+		es_desc->bSegmentType = UAC3_END_SEGMENT;
+	}
+	return cluster_desc;
+}
+
+static struct uac3_feature_unit_descriptor *alloc_fu_desc(unsigned int ch,
+							  u8 unit_id,
+							  u8 source_id)
+{
+	struct uac3_feature_unit_descriptor *fu_desc;
+	__le32 *bma_control;
+
+	fu_desc = kzalloc(UAC3_DT_FEATURE_UNIT_SIZE(ch), GFP_KERNEL);
+	if (!fu_desc)
+		return NULL;
+
+	fu_desc->bLength = UAC3_DT_FEATURE_UNIT_SIZE(ch);
+	fu_desc->bDescriptorType = USB_DT_CS_INTERFACE;
+	fu_desc->bDescriptorSubtype = UAC3_FEATURE_UNIT;
+	fu_desc->bUnitID = unit_id;
+	fu_desc->bSourceID = source_id;
+
+	bma_control = (__le32 *)&fu_desc->bmaControls;
+
+	/* REVISIT: currently hardcoded as described in BADP spec */
+	/* Master Channel: Only a Mute Control shall be present */
+	*bma_control++ = cpu_to_le32(CONTROL_RDWR << ((UAC_FU_MUTE - 1) * 2));
+	/* Channel 1+ : Only a Volume Control shall be present  */
+	while (ch--)
+		*bma_control++ = cpu_to_le32(CONTROL_RDWR << ((UAC_FU_VOLUME - 1) * 2));
+
+	/* fu_desc->wFeatureDescrStr := Not used */
+
+	return fu_desc;
+}
+
+static void set_ep_max_packet_size(const struct f_uac3_opts *uac3_opts,
+				   struct usb_endpoint_descriptor *ep_desc,
+				   unsigned int factor, bool is_playback)
+{
+	int chmask, srate, ssize;
+	u16 max_packet_size;
+
+	if (is_playback) {
+		chmask = uac3_opts->p_chmask;
+		srate = uac3_opts->p_srate;
+		ssize = uac3_opts->p_ssize;
+	} else {
+		chmask = uac3_opts->c_chmask;
+		srate = uac3_opts->c_srate;
+		ssize = uac3_opts->c_ssize;
+	}
+
+	max_packet_size = num_channels(chmask) * ssize *
+		DIV_ROUND_UP(srate, factor / (1 << (ep_desc->bInterval - 1)));
+	ep_desc->wMaxPacketSize = cpu_to_le16(min_t(u16, max_packet_size,
+				le16_to_cpu(ep_desc->wMaxPacketSize)));
+}
+
+#define UAC3_COPY_DESCRIPTOR(mem, dst, desc) \
+	do { \
+		memcpy(mem, desc, (desc)->bLength); \
+		*(dst)++ = mem; \
+		mem += (desc)->bLength; \
+	} while (0)
+
+static struct usb_descriptor_header **
+uac3_copy_descriptors(enum usb_device_speed speed)
+{
+	struct usb_descriptor_header **uac3_control_desc = fs_ac_audio_desc;
+	struct usb_descriptor_header **uac3_streaming_desc;
+
+	struct usb_descriptor_header **tmp;
+	unsigned bytes;
+	unsigned n_desc;
+	void *mem;
+	struct usb_descriptor_header **ret;
+
+	switch (speed) {
+	case USB_SPEED_HIGH:
+		uac3_streaming_desc = hs_as_audio_desc;
+		break;
+
+	case USB_SPEED_FULL:
+	default:
+		uac3_streaming_desc = fs_as_audio_desc;
+		break;
+	}
+
+	/* Count descriptors and their sizes */
+	for (bytes = 0, n_desc = 0, tmp = uac3_control_desc; *tmp; tmp++, n_desc++)
+		bytes += (*tmp)->bLength;
+	if (usb_out_fu_desc) {
+		bytes += usb_out_fu_desc->bLength;
+		n_desc++;
+	}
+	if (usb_in_fu_desc) {
+		bytes += usb_in_fu_desc->bLength;
+		n_desc++;
+	}
+	for (tmp = uac3_streaming_desc; *tmp; tmp++, n_desc++)
+		bytes += (*tmp)->bLength;
+	bytes += (n_desc + 1) * sizeof(*tmp);
+
+	mem = kmalloc(bytes, GFP_KERNEL);
+	if (!mem)
+		return NULL;
+
+	/* fill in pointers starting at "tmp",
+	 * to descriptors copied starting at "mem";
+	 * and return "ret"
+	 */
+	tmp = mem;
+	ret = mem;
+	mem += (n_desc + 1) * sizeof(*tmp);
+	while (*uac3_control_desc) {
+		memcpy(mem, *uac3_control_desc, (*uac3_control_desc)->bLength);
+		*tmp = mem;
+		tmp++;
+		mem += (*uac3_control_desc)->bLength;
+		uac3_control_desc++;
+	}
+
+	if (usb_out_fu_desc)
+		UAC3_COPY_DESCRIPTOR(mem, tmp, usb_out_fu_desc);
+	if (usb_in_fu_desc)
+		UAC3_COPY_DESCRIPTOR(mem, tmp, usb_in_fu_desc);
+
+	while (*uac3_streaming_desc) {
+		memcpy(mem, *uac3_streaming_desc, (*uac3_streaming_desc)->bLength);
+		*tmp = mem;
+		tmp++;
+		mem += (*uac3_streaming_desc)->bLength;
+		uac3_streaming_desc++;
+	}
+	*tmp = NULL;
+
+	return ret;
+}
+
+static int f_audio_bind(struct usb_configuration *cfg, struct usb_function *fn)
+{
+	struct f_uac3 *uac3 = func_to_uac3(fn);
+	struct g_audio *audio = func_to_g_audio(fn);
+	struct usb_composite_dev *cdev = cfg->cdev;
+	struct usb_gadget *gadget = cdev->gadget;
+	struct device *dev = &gadget->dev;
+	struct f_uac3_opts *uac3_opts;
+	struct uac3_hc_descriptor_header *cluster_desc;
+	struct uac3_hc_desc *hc_desc;
+	struct usb_string *us;
+	u16 hc_desc_id = 1; /* HC id always starts from 1 */
+	int ret;
+
+	uac3_opts = container_of(fn->fi, struct f_uac3_opts, func_inst);
+
+	us = usb_gstrings_attach(cdev, fn_strings, ARRAY_SIZE(strings_fn));
+	if (IS_ERR(us))
+		return PTR_ERR(us);
+
+	iad_desc.iFunction = us[STR_ASSOC].id;
+	std_ac_if_desc.iInterface = us[STR_IF_CTRL].id;
+	std_as_out_if0_desc.iInterface = us[STR_AS_OUT_ALT0].id;
+	std_as_out_if1_desc.iInterface = us[STR_AS_OUT_ALT1].id;
+	std_as_in_if0_desc.iInterface = us[STR_AS_IN_ALT0].id;
+	std_as_in_if1_desc.iInterface = us[STR_AS_IN_ALT1].id;
+
+	INIT_LIST_HEAD(&uac3->hc_desc_list);
+
+	/* Initialize the configurable parameters */
+	cluster_desc = build_cluster_descriptor(uac3_opts, 0); /* capture */
+	if (cluster_desc) {
+		hc_desc = kzalloc(sizeof *hc_desc, GFP_KERNEL);
+		hc_desc->hc_header = cluster_desc;
+		list_add(&hc_desc->list, &uac3->hc_desc_list);
+		cluster_desc->wDescriptorID = cpu_to_le16(hc_desc_id);
+		usb_out_it_desc.wClusterDescrID = cluster_desc->wDescriptorID;
+		as_out_hdr_desc.wClusterDescrID = cluster_desc->wDescriptorID;
+		hc_desc_id++;
+	}
+
+	cluster_desc = build_cluster_descriptor(uac3_opts, 1); /* playback */
+	if (cluster_desc) {
+		hc_desc = kzalloc(sizeof *hc_desc, GFP_KERNEL);
+		hc_desc->hc_header = cluster_desc;
+		list_add(&hc_desc->list, &uac3->hc_desc_list);
+		cluster_desc->wDescriptorID = cpu_to_le16(hc_desc_id);
+		io_in_it_desc.wClusterDescrID = cluster_desc->wDescriptorID;
+		as_in_hdr_desc.wClusterDescrID = cluster_desc->wDescriptorID;
+	}
+
+	as_out_hdr_desc.bSubslotSize = uac3_opts->c_ssize;
+	as_out_hdr_desc.bBitResolution = uac3_opts->c_ssize * 8;
+	as_in_hdr_desc.bSubslotSize = uac3_opts->p_ssize;
+	as_in_hdr_desc.bBitResolution = uac3_opts->p_ssize * 8;
+
+	/* alloc and configure Feature Unit descriptors */
+	usb_out_fu_desc = alloc_fu_desc(num_channels(uac3_opts->c_chmask),
+					USB_OUT_FU_ID,
+					USB_OUT_IT_ID);
+	if (!usb_out_fu_desc) {
+		dev_err(dev, "%s: can't allocate OUT FU descriptor on %s\n",
+				 fn->name, gadget->name);
+		ret = -ENOMEM;
+		goto err_free_hc_desc;
+	}
+
+	usb_in_fu_desc = alloc_fu_desc(num_channels(uac3_opts->p_chmask),
+					USB_IN_FU_ID,
+					IO_IN_IT_ID);
+	if (!usb_in_fu_desc) {
+		dev_err(dev, "%s: can't allocate IN FU descriptor on %s\n",
+				 fn->name, gadget->name);
+		ret = -ENOMEM;
+		goto err_free_out_fu_desc;
+	}
+
+	/* update AC desc size with allocated FUs */
+	ac_hdr_desc.wTotalLength = cpu_to_le16(
+			  sizeof in_clk_src_desc + sizeof out_clk_src_desc
+			+ sizeof usb_out_it_desc + sizeof io_in_it_desc
+			+ sizeof usb_in_ot_desc + sizeof io_out_ot_desc
+			+ sizeof usb_in_pd_desc + sizeof usb_out_pd_desc
+			+ usb_out_fu_desc->bLength + usb_in_fu_desc->bLength);
+
+	ret = usb_interface_id(cfg, fn);
+	if (ret < 0) {
+		dev_err(dev, "%s: can't allocate AC interface id on %s\n",
+				 fn->name, gadget->name);
+		goto err_free_in_fu_desc;
+	}
+	std_ac_if_desc.bInterfaceNumber = ret;
+	uac3->ac_intf = ret;
+	uac3->ac_alt = 0;
+
+	ret = usb_interface_id(cfg, fn);
+	if (ret < 0) {
+		dev_err(dev, "%s: can't allocate AS OUT interface id on %s\n",
+				 fn->name, gadget->name);
+		goto err_free_in_fu_desc;
+	}
+	std_as_out_if0_desc.bInterfaceNumber = ret;
+	std_as_out_if1_desc.bInterfaceNumber = ret;
+	uac3->as_out_intf = ret;
+	uac3->as_out_alt = 0;
+
+	ret = usb_interface_id(cfg, fn);
+	if (ret < 0) {
+		dev_err(dev, "%s: can't allocate AS IN interface id on %s\n",
+				 fn->name, gadget->name);
+		goto err_free_in_fu_desc;
+	}
+	std_as_in_if0_desc.bInterfaceNumber = ret;
+	std_as_in_if1_desc.bInterfaceNumber = ret;
+	uac3->as_in_intf = ret;
+	uac3->as_in_alt = 0;
+
+	/* Calculate wMaxPacketSize according to audio bandwidth */
+	set_ep_max_packet_size(uac3_opts, &fs_epin_desc, 1000, true);
+	set_ep_max_packet_size(uac3_opts, &fs_epout_desc, 1000, false);
+	set_ep_max_packet_size(uac3_opts, &hs_epin_desc, 8000, true);
+	set_ep_max_packet_size(uac3_opts, &hs_epout_desc, 8000, false);
+
+	audio->out_ep = usb_ep_autoconfig(gadget, &fs_epout_desc);
+	if (!audio->out_ep) {
+		dev_err(dev, "%s: can't autoconfigure on %s\n",
+				 fn->name, gadget->name);
+		ret = -ENODEV;
+		goto err_free_in_fu_desc;
+	}
+
+	audio->in_ep = usb_ep_autoconfig(gadget, &fs_epin_desc);
+	if (!audio->in_ep) {
+		dev_err(dev, "%s: can't autoconfigure on %s\n",
+				 fn->name, gadget->name);
+		ret = -ENODEV;
+		goto err_free_in_fu_desc;
+	}
+
+	audio->in_ep_maxpsize = max_t(u16,
+				le16_to_cpu(fs_epin_desc.wMaxPacketSize),
+				le16_to_cpu(hs_epin_desc.wMaxPacketSize));
+	audio->out_ep_maxpsize = max_t(u16,
+				le16_to_cpu(fs_epout_desc.wMaxPacketSize),
+				le16_to_cpu(hs_epout_desc.wMaxPacketSize));
+
+	hs_epout_desc.bEndpointAddress = fs_epout_desc.bEndpointAddress;
+	hs_epin_desc.bEndpointAddress = fs_epin_desc.bEndpointAddress;
+
+	/* Copy descriptors */
+	fn->fs_descriptors = uac3_copy_descriptors(USB_SPEED_FULL);
+	if (!fn->fs_descriptors)
+		goto err_free_in_fu_desc;
+	if (gadget_is_dualspeed(gadget)) {
+		fn->hs_descriptors = uac3_copy_descriptors(USB_SPEED_HIGH);
+		if (!fn->hs_descriptors)
+			goto err_free_in_fu_desc;
+	}
+
+	audio->gadget = gadget;
+
+	audio->params.p_chmask = uac3_opts->p_chmask;
+	audio->params.p_srate = uac3_opts->p_srate;
+	audio->params.p_ssize = uac3_opts->p_ssize;
+	audio->params.c_chmask = uac3_opts->c_chmask;
+	audio->params.c_srate = uac3_opts->c_srate;
+	audio->params.c_ssize = uac3_opts->c_ssize;
+	audio->params.req_number = uac3_opts->req_number;
+	ret = g_audio_setup(audio, "UAC3 PCM", "UAC3_Gadget");
+	if (ret)
+		goto err_free_descs;
+	return 0;
+
+err_free_descs:
+	usb_free_all_descriptors(fn);
+	audio->gadget = NULL;
+err_free_in_fu_desc:
+	kfree(usb_in_fu_desc);
+	usb_in_fu_desc = NULL;
+err_free_out_fu_desc:
+	kfree(usb_out_fu_desc);
+	usb_out_fu_desc = NULL;
+err_free_hc_desc:
+	list_for_each_entry(hc_desc, &uac3->hc_desc_list, list)
+		kfree(hc_desc);
+
+	return ret;
+}
+
+static void f_audio_unbind(struct usb_configuration *c, struct usb_function *f)
+{
+	struct g_audio *audio = func_to_g_audio(f);
+	struct f_uac3 *uac3 = func_to_uac3(f);
+	struct uac3_hc_desc *hc_desc;
+
+	g_audio_cleanup(audio);
+	usb_free_all_descriptors(f);
+	audio->gadget = NULL;
+	kfree(usb_in_fu_desc);
+	usb_in_fu_desc = NULL;
+	kfree(usb_out_fu_desc);
+	usb_out_fu_desc = NULL;
+
+	list_for_each_entry(hc_desc, &uac3->hc_desc_list, list)
+		kfree(hc_desc);
+}
+
+static int f_audio_set_alt(struct usb_function *fn, unsigned intf, unsigned alt)
+{
+	struct usb_composite_dev *cdev = fn->config->cdev;
+	struct f_uac3 *uac3 = func_to_uac3(fn);
+	struct usb_gadget *gadget = cdev->gadget;
+	struct device *dev = &gadget->dev;
+	int ret = 0;
+
+	/* No i/f has more than 2 alt settings */
+	if (alt > 1) {
+		dev_err(dev, "%s: Invalid altsetting %d\n", fn->name, alt);
+		return -EINVAL;
+	}
+
+	if (intf == uac3->ac_intf) {
+		/* Control I/f has only 1 AltSetting - 0 */
+		if (alt) {
+			dev_err(dev,
+				"%s: Invalid Control I/f altsetting %d\n",
+				fn->name, alt);
+			return -EINVAL;
+		}
+		return 0;
+	}
+
+	if (intf == uac3->as_out_intf) {
+		uac3->as_out_alt = alt;
+
+		if (alt)
+			ret = u_audio_start_capture(&uac3->g_audio);
+		else
+			u_audio_stop_capture(&uac3->g_audio);
+	} else if (intf == uac3->as_in_intf) {
+		uac3->as_in_alt = alt;
+
+		if (alt)
+			ret = u_audio_start_playback(&uac3->g_audio);
+		else
+			u_audio_stop_playback(&uac3->g_audio);
+	} else {
+		dev_err(dev, "%s: Invalid interface %d\n", fn->name, intf);
+		return -EINVAL;
+	}
+
+	return ret;
+}
+
+static int f_audio_get_alt(struct usb_function *fn, unsigned intf)
+{
+	struct f_uac3 *uac3 = func_to_uac3(fn);
+	struct g_audio *audio = func_to_g_audio(fn);
+
+	if (intf == uac3->ac_intf)
+		return uac3->ac_alt;
+	else if (intf == uac3->as_out_intf)
+		return uac3->as_out_alt;
+	else if (intf == uac3->as_in_intf)
+		return uac3->as_in_alt;
+	else
+		dev_err(&audio->gadget->dev, "%s: Invalid interface %d\n",
+							fn->name, intf);
+
+	return -EINVAL;
+}
+
+static void f_audio_disable(struct usb_function *fn)
+{
+	struct f_uac3 *uac3 = func_to_uac3(fn);
+
+	uac3->as_in_alt = 0;
+	uac3->as_out_alt = 0;
+	u_audio_stop_capture(&uac3->g_audio);
+	u_audio_stop_playback(&uac3->g_audio);
+}
+
+static int in_rq_cur(struct usb_function *fn, const struct usb_ctrlrequest *cr)
+{
+	struct usb_request *req = fn->config->cdev->req;
+	struct g_audio *audio = func_to_g_audio(fn);
+	struct f_uac3_opts *opts;
+	u16 w_length = le16_to_cpu(cr->wLength);
+	u16 w_index = le16_to_cpu(cr->wIndex);
+	u16 w_value = le16_to_cpu(cr->wValue);
+	u8 entity_id = (w_index >> 8) & 0xff;
+	u8 control_selector = w_value >> 8;
+	int value = -EOPNOTSUPP;
+	int p_srate, c_srate;
+
+	opts = g_audio_to_uac3_opts(audio);
+	p_srate = opts->p_srate;
+	c_srate = opts->c_srate;
+
+	switch (entity_id) {
+	case USB_IN_CLK_ID:
+	case USB_OUT_CLK_ID:
+		if (control_selector == UAC2_CS_CONTROL_SAM_FREQ) {
+			struct cntrl_cur_lay3 c;
+			memset(&c, 0, sizeof(struct cntrl_cur_lay3));
+
+			if (entity_id == USB_IN_CLK_ID)
+				c.dCUR = cpu_to_le32(p_srate);
+			else if (entity_id == USB_OUT_CLK_ID)
+				c.dCUR = cpu_to_le32(c_srate);
+
+			value = min_t(unsigned, w_length, sizeof c);
+			memcpy(req->buf, &c, value);
+		} else if (control_selector == UAC2_CS_CONTROL_CLOCK_VALID) {
+			*(u8 *)req->buf = 1;
+			value = min_t(unsigned, w_length, 1);
+		} else {
+			dev_err(&audio->gadget->dev,
+				"%s:%d control_selector=%d TODO!\n",
+				__func__, __LINE__, control_selector);
+		}
+		break;
+
+	case USB_OUT_PD_ID:
+	case USB_IN_PD_ID:
+		if (control_selector == UAC3_AC_POWER_DOMAIN_CONTROL) {
+			/* FIXME: hardcoded to Power Domain State D0 */
+			*(u8 *)req->buf = 0;
+			value = min_t(unsigned, w_length, 1);
+		} else {
+			dev_err(&audio->gadget->dev,
+				"%s:%d control_selector=%d TODO!\n",
+				__func__, __LINE__, control_selector);
+		}
+		break;
+
+	case USB_IN_FU_ID:
+	case USB_OUT_FU_ID:
+		if (control_selector == UAC_FU_MUTE) {
+			/* FIXME: hardcoded to false (not muted) */
+			*(u8 *)req->buf = 0;
+			value = min_t(unsigned, w_length, 1);
+		} else if (control_selector == UAC_FU_VOLUME) {
+			struct cntrl_cur_lay2 r;
+
+			/* FIXME: hardcoded to 0dB */
+			r.wCUR = 0;
+
+			value = min_t(unsigned, w_length, sizeof r);
+			memcpy(req->buf, &r, value);
+		} else {
+			dev_err(&audio->gadget->dev,
+				"%s:%d control_selector=%d TODO!\n",
+				__func__, __LINE__, control_selector);
+		}
+		break;
+
+	default:
+		value = -EOPNOTSUPP;
+		break;
+	}
+
+	return value;
+}
+
+static int
+in_rq_range(struct usb_function *fn, const struct usb_ctrlrequest *cr)
+{
+	struct usb_request *req = fn->config->cdev->req;
+	struct g_audio *audio = func_to_g_audio(fn);
+	struct f_uac3_opts *opts;
+	u16 w_length = le16_to_cpu(cr->wLength);
+	u16 w_index = le16_to_cpu(cr->wIndex);
+	u16 w_value = le16_to_cpu(cr->wValue);
+	u8 entity_id = (w_index >> 8) & 0xff;
+	u8 control_selector = w_value >> 8;
+	int value = -EOPNOTSUPP;
+	int p_srate, c_srate;
+
+	opts = g_audio_to_uac3_opts(audio);
+	p_srate = opts->p_srate;
+	c_srate = opts->c_srate;
+
+
+	switch (entity_id) {
+	case USB_IN_CLK_ID:
+	case USB_OUT_CLK_ID: {
+		if (control_selector == UAC2_CS_CONTROL_SAM_FREQ) {
+			struct cntrl_range_lay3 r;
+
+			if (entity_id == USB_IN_CLK_ID)
+				r.dMIN = cpu_to_le32(p_srate);
+			else if (entity_id == USB_OUT_CLK_ID)
+				r.dMIN = cpu_to_le32(c_srate);
+			else
+				return -EOPNOTSUPP;
+
+			r.dMAX = r.dMIN;
+			r.dRES = 0;
+			r.wNumSubRanges = cpu_to_le16(1);
+
+			value = min_t(unsigned, w_length, sizeof r);
+			memcpy(req->buf, &r, value);
+		} else {
+			dev_err(&audio->gadget->dev,
+				"%s:%d control_selector=%d TODO!\n",
+				__func__, __LINE__, control_selector);
+		}
+		break;
+	}
+	case USB_IN_FU_ID:
+	case USB_OUT_FU_ID: {
+		if (control_selector == UAC_FU_VOLUME) {
+			struct cntrl_range_lay2 r;
+
+			r.wMIN = cpu_to_le16(0x8001); /* -127.9961 dB */
+			r.wMAX = 0; /* 0 dB */
+			r.wRES = cpu_to_le16(0x0001); /* in steps of 1/256 dB */
+			r.wNumSubRanges = cpu_to_le16(1);
+
+			value = min_t(unsigned, w_length, sizeof r);
+			memcpy(req->buf, &r, value);
+		} else {
+			dev_err(&audio->gadget->dev,
+				"%s:%d control_selector=%d TODO!\n",
+				__func__, __LINE__, control_selector);
+		}
+		break;
+	}
+	default:
+		dev_err(&audio->gadget->dev,
+			"%s:%d control_selector=%d TODO!\n",
+			__func__, __LINE__, control_selector);
+
+	}
+
+
+	return value;
+}
+
+static int out_rq_cur(struct usb_function *fn, const struct usb_ctrlrequest *cr)
+{
+	struct g_audio *audio = func_to_g_audio(fn);
+	u16 w_length = le16_to_cpu(cr->wLength);
+	u16 w_value = le16_to_cpu(cr->wValue);
+	u16 w_index = le16_to_cpu(cr->wIndex);
+	u8 entity_id = (w_index >> 8) & 0xff;
+	u8 control_selector = w_value >> 8;
+	int value = -EOPNOTSUPP;
+
+	/* TODO: implement real clock/mute/volume handling */
+	switch (entity_id) {
+	case USB_IN_CLK_ID:
+	case USB_OUT_CLK_ID:
+		if (control_selector == UAC2_CS_CONTROL_SAM_FREQ)
+			value = w_length;
+		break;
+
+	case USB_IN_FU_ID:
+	case USB_OUT_FU_ID:
+		if ((control_selector == UAC_FU_MUTE)
+				|| (control_selector == UAC_FU_VOLUME))
+			value = w_length;
+		break;
+
+	default:
+		dev_err(&audio->gadget->dev,
+			"%s:%d control_selector=%d TODO!\n",
+			__func__, __LINE__, control_selector);
+	}
+
+	return value;
+}
+
+static int
+in_rq_hc_desc(struct usb_function *fn, const struct usb_ctrlrequest *cr)
+{
+	struct f_uac3 *uac3 = func_to_uac3(fn);
+	struct g_audio *audio = func_to_g_audio(fn);
+	struct usb_request *req = fn->config->cdev->req;
+	u16 w_length = le16_to_cpu(cr->wLength);
+	u16 w_value = le16_to_cpu(cr->wValue);
+	struct uac3_hc_desc *hc_desc;
+	u16 hc_desc_len;
+	int value;
+
+	list_for_each_entry(hc_desc, &uac3->hc_desc_list, list) {
+		u16 w_desc_id;
+
+		w_desc_id = le16_to_cpu(hc_desc->hc_header->wDescriptorID);
+		if (w_desc_id == w_value)
+			goto found;
+	}
+	dev_err(&audio->gadget->dev, "No High Capability descriptor %d\n",
+				     w_value);
+	return -EOPNOTSUPP;
+
+found:
+	hc_desc_len = le16_to_cpu(hc_desc->hc_header->wLength);
+	value = min_t(unsigned, w_length, hc_desc_len);
+	memcpy(req->buf, hc_desc->hc_header, value);
+
+	return value;
+}
+
+static int ac_rq_in(struct usb_function *fn, const struct usb_ctrlrequest *cr)
+{
+	if (cr->bRequest == UAC3_CS_REQ_CUR)
+		return in_rq_cur(fn, cr);
+	else if (cr->bRequest == UAC3_CS_REQ_RANGE)
+		return in_rq_range(fn, cr);
+	else if (cr->bRequest == UAC3_CS_REQ_HIGH_CAPABILITY_DESCRIPTOR)
+		return in_rq_hc_desc(fn, cr);
+	else
+		return -EOPNOTSUPP;
+}
+
+static int
+setup_rq_inf(struct usb_function *fn, const struct usb_ctrlrequest *cr)
+{
+	struct f_uac3 *uac3 = func_to_uac3(fn);
+	struct g_audio *audio = func_to_g_audio(fn);
+	u16 w_index = le16_to_cpu(cr->wIndex);
+	u8 intf = w_index & 0xff;
+
+	if (intf != uac3->ac_intf) {
+		dev_err(&audio->gadget->dev,
+			"%s:%d Error!\n", __func__, __LINE__);
+		return -EOPNOTSUPP;
+	}
+
+	if (cr->bRequestType & USB_DIR_IN)
+		return ac_rq_in(fn, cr);
+	else if (cr->bRequest == UAC3_CS_REQ_CUR)
+		return out_rq_cur(fn, cr);
+
+	return -EOPNOTSUPP;
+}
+
+static int
+f_audio_setup(struct usb_function *fn, const struct usb_ctrlrequest *cr)
+{
+	struct usb_composite_dev *cdev = fn->config->cdev;
+	struct g_audio *audio = func_to_g_audio(fn);
+	struct usb_request *req = cdev->req;
+	u16 w_length = le16_to_cpu(cr->wLength);
+	int value = -EOPNOTSUPP;
+
+	/* Only Class specific requests are supposed to reach here */
+	if ((cr->bRequestType & USB_TYPE_MASK) != USB_TYPE_CLASS)
+		return -EOPNOTSUPP;
+
+	if ((cr->bRequestType & USB_RECIP_MASK) == USB_RECIP_INTERFACE)
+		value = setup_rq_inf(fn, cr);
+	else
+		dev_err(&audio->gadget->dev, "%s:%d Error!\n",
+				__func__, __LINE__);
+
+	if (value >= 0) {
+		req->length = value;
+		req->zero = value < w_length;
+		value = usb_ep_queue(cdev->gadget->ep0, req, GFP_ATOMIC);
+		if (value < 0) {
+			dev_err(&audio->gadget->dev,
+				"%s:%d Error!\n", __func__, __LINE__);
+			req->status = 0;
+		}
+	}
+
+	return value;
+}
+
+static inline struct f_uac3_opts *to_f_uac3_opts(struct config_item *item)
+{
+	return container_of(to_config_group(item), struct f_uac3_opts,
+			    func_inst.group);
+}
+
+static void f_uac3_attr_release(struct config_item *item)
+{
+	struct f_uac3_opts *opts = to_f_uac3_opts(item);
+
+	usb_put_function_instance(&opts->func_inst);
+}
+
+static struct configfs_item_operations f_uac3_item_ops = {
+	.release	= f_uac3_attr_release,
+};
+
+#define UAC3_ATTRIBUTE_CHMASK(name)					\
+static ssize_t f_uac3_opts_##name##_show(struct config_item *item,	\
+					 char *page)			\
+{									\
+	struct f_uac3_opts *opts = to_f_uac3_opts(item);		\
+	int result;							\
+									\
+	mutex_lock(&opts->lock);					\
+	result = sprintf(page, "%u\n", opts->name);			\
+	mutex_unlock(&opts->lock);					\
+									\
+	return result;							\
+}									\
+									\
+static ssize_t f_uac3_opts_##name##_store(struct config_item *item,	\
+					  const char *page, size_t len)	\
+{									\
+	struct f_uac3_opts *opts = to_f_uac3_opts(item);		\
+	int ret;							\
+	u32 num;							\
+									\
+	mutex_lock(&opts->lock);					\
+	if (opts->refcnt) {						\
+		ret = -EBUSY;						\
+		goto end;						\
+	}								\
+									\
+	ret = kstrtou32(page, 0, &num);					\
+	if (ret)							\
+		goto end;						\
+	/* FIXME: only mono/stereo supported at this time */		\
+	if (num & (~0x3)) {						\
+		ret = -EINVAL;						\
+		goto end;						\
+	}								\
+									\
+	opts->name = num;						\
+	ret = len;							\
+									\
+end:									\
+	mutex_unlock(&opts->lock);					\
+	return ret;							\
+}									\
+									\
+CONFIGFS_ATTR(f_uac3_opts_, name)
+
+#define UAC3_ATTRIBUTE(name)						\
+static ssize_t f_uac3_opts_##name##_show(struct config_item *item,	\
+					 char *page)			\
+{									\
+	struct f_uac3_opts *opts = to_f_uac3_opts(item);		\
+	int result;							\
+									\
+	mutex_lock(&opts->lock);					\
+	result = sprintf(page, "%u\n", opts->name);			\
+	mutex_unlock(&opts->lock);					\
+									\
+	return result;							\
+}									\
+									\
+static ssize_t f_uac3_opts_##name##_store(struct config_item *item,	\
+					  const char *page, size_t len)	\
+{									\
+	struct f_uac3_opts *opts = to_f_uac3_opts(item);		\
+	int ret;							\
+	u32 num;							\
+									\
+	mutex_lock(&opts->lock);					\
+	if (opts->refcnt) {						\
+		ret = -EBUSY;						\
+		goto end;						\
+	}								\
+									\
+	ret = kstrtou32(page, 0, &num);					\
+	if (ret)							\
+		goto end;						\
+									\
+	opts->name = num;						\
+	ret = len;							\
+									\
+end:									\
+	mutex_unlock(&opts->lock);					\
+	return ret;							\
+}									\
+									\
+CONFIGFS_ATTR(f_uac3_opts_, name)
+
+UAC3_ATTRIBUTE_CHMASK(p_chmask);
+UAC3_ATTRIBUTE(p_srate);
+UAC3_ATTRIBUTE(p_ssize);
+UAC3_ATTRIBUTE_CHMASK(c_chmask);
+UAC3_ATTRIBUTE(c_srate);
+UAC3_ATTRIBUTE(c_ssize);
+UAC3_ATTRIBUTE(req_number);
+
+static struct configfs_attribute *f_uac3_attrs[] = {
+	&f_uac3_opts_attr_p_chmask,
+	&f_uac3_opts_attr_p_srate,
+	&f_uac3_opts_attr_p_ssize,
+	&f_uac3_opts_attr_c_chmask,
+	&f_uac3_opts_attr_c_srate,
+	&f_uac3_opts_attr_c_ssize,
+	&f_uac3_opts_attr_req_number,
+	NULL,
+};
+
+static struct config_item_type f_uac3_func_type = {
+	.ct_item_ops	= &f_uac3_item_ops,
+	.ct_attrs	= f_uac3_attrs,
+	.ct_owner	= THIS_MODULE,
+};
+
+static void f_audio_free_inst(struct usb_function_instance *f)
+{
+	struct f_uac3_opts *opts;
+
+	opts = container_of(f, struct f_uac3_opts, func_inst);
+	kfree(opts);
+}
+
+static struct usb_function_instance *f_audio_alloc_inst(void)
+{
+	struct f_uac3_opts *opts;
+
+	opts = kzalloc(sizeof(*opts), GFP_KERNEL);
+	if (!opts)
+		return ERR_PTR(-ENOMEM);
+
+	mutex_init(&opts->lock);
+	opts->func_inst.free_func_inst = f_audio_free_inst;
+
+	config_group_init_type_name(&opts->func_inst.group, "",
+				    &f_uac3_func_type);
+
+	opts->p_chmask = UAC3_DEF_PCHMASK;
+	opts->p_srate = UAC3_DEF_PSRATE;
+	opts->p_ssize = UAC3_DEF_PSSIZE;
+	opts->c_chmask = UAC3_DEF_CCHMASK;
+	opts->c_srate = UAC3_DEF_CSRATE;
+	opts->c_ssize = UAC3_DEF_CSSIZE;
+	opts->req_number = UAC3_DEF_REQ_NUM;
+	return &opts->func_inst;
+}
+
+static void f_audio_free(struct usb_function *f)
+{
+	struct g_audio *audio;
+	struct f_uac3_opts *opts;
+
+	audio = func_to_g_audio(f);
+	opts = container_of(f->fi, struct f_uac3_opts, func_inst);
+	kfree(audio);
+	mutex_lock(&opts->lock);
+	--opts->refcnt;
+	mutex_unlock(&opts->lock);
+}
+
+static struct usb_function *f_audio_alloc(struct usb_function_instance *fi)
+{
+	struct f_uac3	*uac3;
+	struct f_uac3_opts *opts;
+
+	uac3 = kzalloc(sizeof(*uac3), GFP_KERNEL);
+	if (!uac3)
+		return ERR_PTR(-ENOMEM);
+
+	opts = container_of(fi, struct f_uac3_opts, func_inst);
+	mutex_lock(&opts->lock);
+	++opts->refcnt;
+	mutex_unlock(&opts->lock);
+
+	uac3->g_audio.func.name = "uac3_func";
+	uac3->g_audio.func.bind = f_audio_bind;
+	uac3->g_audio.func.unbind = f_audio_unbind;
+	uac3->g_audio.func.set_alt = f_audio_set_alt;
+	uac3->g_audio.func.get_alt = f_audio_get_alt;
+	uac3->g_audio.func.disable = f_audio_disable;
+	uac3->g_audio.func.setup = f_audio_setup;
+	uac3->g_audio.func.free_func = f_audio_free;
+
+	return &uac3->g_audio.func;
+}
+
+DECLARE_USB_FUNCTION_INIT(uac3, f_audio_alloc_inst, f_audio_alloc);
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR("Ruslan Bilovol");
diff --git a/drivers/usb/gadget/function/u_uac3.h b/drivers/usb/gadget/function/u_uac3.h
new file mode 100644
index 0000000..0ad594f
--- /dev/null
+++ b/drivers/usb/gadget/function/u_uac3.h
@@ -0,0 +1,38 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * u_uac3.h
+ *
+ * Utility definitions for UAC3 function
+ *
+ * Author: Ruslan Bilovol <ruslan.bilovol@gmail.com>
+ */
+
+#ifndef __U_UAC3_H
+#define __U_UAC3_H
+
+#include <linux/usb/composite.h>
+
+#define UAC3_DEF_PCHMASK 0x3
+#define UAC3_DEF_PSRATE 48000
+#define UAC3_DEF_PSSIZE 2
+#define UAC3_DEF_CCHMASK 0x3
+#define UAC3_DEF_CSRATE 48000
+#define UAC3_DEF_CSSIZE 2
+#define UAC3_DEF_REQ_NUM 2
+
+struct f_uac3_opts {
+	struct usb_function_instance	func_inst;
+	int				p_chmask;
+	int				p_srate;
+	int				p_ssize;
+	int				c_chmask;
+	int				c_srate;
+	int				c_ssize;
+	int				req_number;
+	bool				bound;
+
+	struct mutex			lock;
+	int				refcnt;
+};
+
+#endif /* __U_UAC3_H */
diff --git a/drivers/usb/gadget/legacy/Kconfig b/drivers/usb/gadget/legacy/Kconfig
index a12fb45..dc104974 100644
--- a/drivers/usb/gadget/legacy/Kconfig
+++ b/drivers/usb/gadget/legacy/Kconfig
@@ -57,7 +57,8 @@ config USB_AUDIO
 	select USB_F_UAC1 if (GADGET_UAC1 && !GADGET_UAC1_LEGACY)
 	select USB_F_UAC1_LEGACY if (GADGET_UAC1 && GADGET_UAC1_LEGACY)
 	select USB_F_UAC2 if !GADGET_UAC1
-	select USB_U_AUDIO if (USB_F_UAC2 || USB_F_UAC1)
+	select USB_F_UAC3 if !GADGET_UAC1_LEGACY
+	select USB_U_AUDIO if (USB_F_UAC3 || USB_F_UAC2 || USB_F_UAC1)
 	help
 	  This Gadget Audio driver is compatible with USB Audio Class
 	  specification 2.0. It implements 1 AudioControl interface,
-- 
1.9.1


From 1583367946918313594@xxx Tue Nov 07 01:15:44 +0000 2017
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