[RFC 15/15] ASoC: Intel: avs: Add USB machine board

[Cezary Rojewski <cezary.rojewski@intel.com>]

Provide machine board driver that represents USB Audio sound card. The
card connects ASoC USB codec driver with Intel AudioDSP avs-driver
driver so that user can enjoy streaming over USB device without engaging
their CPU - transfer is offloaded onto DSP instead.

Signed-off-by: Cezary Rojewski <cezary.rojewski@intel.com>
---
 sound/soc/intel/avs/boards/Kconfig  |   8 ++
 sound/soc/intel/avs/boards/Makefile |   2 +
 sound/soc/intel/avs/boards/usb.c    | 115 ++++++++++++++++++++++++++++
 3 files changed, 125 insertions(+)
 create mode 100644 sound/soc/intel/avs/boards/usb.c

diff --git a/sound/soc/intel/avs/boards/Kconfig b/sound/soc/intel/avs/boards/Kconfig
index 7938e6d6e44d..f036cb96c48f 100644
--- a/sound/soc/intel/avs/boards/Kconfig
+++ b/sound/soc/intel/avs/boards/Kconfig
@@ -244,4 +244,12 @@ config SND_SOC_INTEL_AVS_MACH_TDF8532
 	  Say Y or m if you have such a device. This is a recommended option.
 	  If unsure select "N".
 
+config SND_SOC_INTEL_AVS_MACH_USB
+	tristate "USB-Audio board"
+	depends on USB_XHCI_PCI || COMPILE_TEST
+	select SND_SOC_USB_CODEC
+	help
+	  This allows Intel AVS driver to pair with xHCI Audio Sideband.
+	  If unsure select "N".
+
 endmenu
diff --git a/sound/soc/intel/avs/boards/Makefile b/sound/soc/intel/avs/boards/Makefile
index 7c718c0ce120..4fdea026a216 100644
--- a/sound/soc/intel/avs/boards/Makefile
+++ b/sound/soc/intel/avs/boards/Makefile
@@ -24,6 +24,7 @@ snd-soc-avs-rt5663-y := rt5663.o
 snd-soc-avs-rt5682-y := rt5682.o
 snd-soc-avs-ssm4567-y := ssm4567.o
 snd-soc-avs-tdf8532-y := tdf8532.o
+snd-soc-avs-usb-y := usb.o
 
 obj-$(CONFIG_SND_SOC_INTEL_AVS_MACH_DA7219) += snd-soc-avs-da7219.o
 obj-$(CONFIG_SND_SOC_INTEL_AVS_MACH_DMIC) += snd-soc-avs-dmic.o
@@ -49,3 +50,4 @@ obj-$(CONFIG_SND_SOC_INTEL_AVS_MACH_RT5663) += snd-soc-avs-rt5663.o
 obj-$(CONFIG_SND_SOC_INTEL_AVS_MACH_RT5682) += snd-soc-avs-rt5682.o
 obj-$(CONFIG_SND_SOC_INTEL_AVS_MACH_SSM4567) += snd-soc-avs-ssm4567.o
 obj-$(CONFIG_SND_SOC_INTEL_AVS_MACH_TDF8532) += snd-soc-avs-tdf8532.o
+obj-$(CONFIG_SND_SOC_INTEL_AVS_MACH_USB) += snd-soc-avs-usb.o
diff --git a/sound/soc/intel/avs/boards/usb.c b/sound/soc/intel/avs/boards/usb.c
new file mode 100644
index 000000000000..d103a8a5474b
--- /dev/null
+++ b/sound/soc/intel/avs/boards/usb.c
@@ -0,0 +1,115 @@
+// SPDX-License-Identifier: GPL-2.0
+//
+// Copyright(c) 2025 Intel Corporation
+//
+// Author: Cezary Rojewski <cezary.rojewski@intel.com>
+//
+
+#include <linux/mod_devicetable.h>
+#include <linux/platform_device.h>
+#include <linux/usb.h>
+#include <sound/soc.h>
+#include <sound/soc-card.h>
+#include <sound/usb.h>
+
+static int uao_create_dai_links(struct device *dev, struct snd_usb_audio *chip,
+				struct snd_soc_dai_link **links, int *num_links)
+{
+	struct snd_soc_dai_link *dl;
+	int i;
+
+	dl = devm_kcalloc(dev, chip->pcm_devs, sizeof(*dl), GFP_KERNEL);
+	if (!dl)
+		return -ENOMEM;
+
+	for (i = 0; i < chip->pcm_devs; i++) {
+		dl[i].name = devm_kasprintf(dev, GFP_KERNEL, "uao-be-link%d", i);
+		if (!dl[i].name)
+			return -ENOMEM;
+		dl[i].stream_name = dl[i].name;
+
+		dl[i].no_pcm = 1;
+		dl[i].num_cpus = 1;
+		dl[i].num_codecs = 1;
+		dl[i].nonatomic = 1;
+		dl[i].codecs = devm_kzalloc(dev, sizeof(*dl[i].codecs), GFP_KERNEL);
+		dl[i].cpus = devm_kzalloc(dev, sizeof(*dl[i].cpus), GFP_KERNEL);
+		if (!dl[i].codecs || !dl[i].cpus)
+			return -ENOMEM;
+		dl[i].codecs->name = "usb-codec";
+		dl[i].codecs->dai_name = devm_kasprintf(dev, GFP_KERNEL, "usb-codec-dai%d", i);
+		if (!dl[i].codecs->dai_name)
+			return -ENOMEM;
+		dl[i].cpus->dai_name = "uaol-cpu0";
+	}
+
+	*links = dl;
+	*num_links = chip->pcm_devs;
+	return 0;
+}
+
+static int uao_board_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct snd_usb_audio *chip;
+	struct snd_soc_card *card;
+	struct usb_device *udev;
+	char shortname[32];
+	char longname[80];
+	int ret;
+
+	chip = dev_get_drvdata(dev->parent);
+	udev = chip->dev;
+
+	switch (udev->speed) {
+	case USB_SPEED_FULL:
+	case USB_SPEED_HIGH:
+		break;
+	default:
+		return -EOPNOTSUPP;
+	}
+
+	card = devm_kzalloc(dev, sizeof(*card), GFP_KERNEL);
+	if (!card)
+		return -ENOMEM;
+
+	ret = uao_create_dai_links(dev, chip, &card->dai_link, &card->num_links);
+	if (ret)
+		return ret;
+
+	card->dev = dev;
+	card->owner = THIS_MODULE;
+	card->fully_routed = true;
+	card->driver_name = "USB-Audio";
+
+	snd_usb_make_card_names(chip, shortname, longname);
+	/* card->driver/shortname/longname set by ASoC. */
+	/* card->private_data/free redundant for ASoC-based. */
+	card->name = devm_kstrdup(dev, shortname, GFP_KERNEL);
+	card->long_name = devm_kstrdup(dev, longname, GFP_KERNEL);
+	card->components = devm_kasprintf(dev, GFP_KERNEL, "USB%04x:%04x",
+					  usb_device_vid(udev), usb_device_pid(udev));
+	if (!card->name || !card->long_name || !card->components)
+		return -ENOMEM;
+
+	return devm_snd_soc_register_card(dev, card);
+}
+
+static const struct platform_device_id uao_board_driver_ids[] = {
+	{ .name = "uao_board", },
+	{ },
+};
+
+static struct platform_driver uao_board_driver = {
+	.probe = uao_board_probe,
+	.driver = {
+		.name = "uao_board",
+		.pm = &snd_soc_pm_ops,
+	},
+	.id_table = uao_board_driver_ids,
+};
+
+module_platform_driver(uao_board_driver);
+
+MODULE_DESCRIPTION("USB Audio Offload machine driver");
+MODULE_LICENSE("GPL");
-- 
2.25.1