Merge "usb: core: Add support to handle multi config audio device"

drivers/usb/core/config.c

@@ -949,6 +949,14 @@ int usb_get_bos_descriptor(struct usb_device *dev)
 			dev->bos->ss_id =
 				(struct usb_ss_container_id_descriptor *)buffer;
 			break;
+		case USB_CAP_TYPE_CONFIG_SUMMARY:
+			/* one such desc per configuration */
+			if (!dev->bos->num_config_summary_desc)
+				dev->bos->config_summary =
+				(struct usb_config_summary_descriptor *)buffer;
+
+			dev->bos->num_config_summary_desc++;
+			break;
 		default:
 			break;
 		}

drivers/usb/core/generic.c

@@ -19,6 +19,8 @@
 
 #include <linux/usb.h>
 #include <linux/usb/hcd.h>
+#include <linux/usb/audio.h>
+#include <linux/usb/audio-v3.h>
 #include "usb.h"
 
 static inline const char *plural(int n)
@@ -40,6 +42,36 @@ static int is_activesync(struct usb_interface_descriptor *desc)
 		&& desc->bInterfaceProtocol == 1;
 }
 
+static int usb_audio_max_rev_config(struct usb_host_bos *bos)
+{
+	int desc_cnt, func_cnt, numfunc;
+	int num_cfg_desc;
+	struct usb_config_summary_descriptor *conf_summary;
+
+	if (!bos || !bos->config_summary)
+		goto done;
+
+	conf_summary = bos->config_summary;
+	num_cfg_desc = bos->num_config_summary_desc;
+
+	for (desc_cnt = 0; desc_cnt < num_cfg_desc; desc_cnt++) {
+		numfunc = conf_summary->bNumFunctions;
+		for (func_cnt = 0; func_cnt < numfunc; func_cnt++) {
+			/* look for BADD 3.0 */
+			if (conf_summary->cs_info[func_cnt].bClass ==
+				USB_CLASS_AUDIO &&
+				conf_summary->cs_info[func_cnt].bProtocol ==
+				UAC_VERSION_3 &&
+				conf_summary->cs_info[func_cnt].bSubClass !=
+				FULL_ADC_PROFILE)
+				return conf_summary->bConfigurationValue;
+		}
+	}
+
+done:
+	return -EINVAL;
+}
+
 int usb_choose_configuration(struct usb_device *udev)
 {
 	int i;
@@ -130,7 +162,6 @@ int usb_choose_configuration(struct usb_device *udev)
 			best = c;
 			break;
 		}
-
 		/* If all the remaining configs are vendor-specific,
 		 * choose the first one. */
 		else if (!best)
@@ -143,7 +174,10 @@ int usb_choose_configuration(struct usb_device *udev)
 			insufficient_power, plural(insufficient_power));
 
 	if (best) {
-		i = best->desc.bConfigurationValue;
+		/* choose usb audio class preferred config if available */
+		i = usb_audio_max_rev_config(udev->bos);
+		if (i < 0)
+			i = best->desc.bConfigurationValue;
 		dev_dbg(&udev->dev,
 			"configuration #%d chosen from %d choice%s\n",
 			i, num_configs, plural(num_configs));

include/linux/usb.h

@@ -330,6 +330,8 @@ struct usb_host_bos {
 	struct usb_ss_cap_descriptor	*ss_cap;
 	struct usb_ssp_cap_descriptor	*ssp_cap;
 	struct usb_ss_container_id_descriptor	*ss_id;
+	struct usb_config_summary_descriptor	*config_summary;
+	unsigned int	num_config_summary_desc;
 };
 
 int __usb_get_extra_descriptor(char *buffer, unsigned size,

include/uapi/linux/usb/ch9.h

@@ -894,6 +894,29 @@ struct usb_ssp_cap_descriptor {
 #define USB_SSP_SUBLINK_SPEED_LSM	(0xff << 16)	/* Lanespeed mantissa */
 } __attribute__((packed));
 
+/*
+ * Configuration Summary descriptors: Defines a list of functions in the
+ * configuration. This descriptor may be used by Host software to decide
+ * which Configuration to use to obtain the desired functionality.
+ */
+#define	USB_CAP_TYPE_CONFIG_SUMMARY	0x10
+
+struct function_class_info {
+	__u8 bClass;
+	__u8 bSubClass;
+	__u8 bProtocol;
+};
+
+struct usb_config_summary_descriptor {
+	__u8 bLength;
+	__u8 bDescriptorType;
+	__u8 bDevCapabilityType;
+	__u16 bcdVersion;
+	__u8 bConfigurationValue;
+	__u8 bMaxPower;
+	__u8 bNumFunctions;
+	struct function_class_info cs_info[];
+} __attribute__((packed));
 
 /*-------------------------------------------------------------------------*/