From e5223a9107e5ee250ad67ea4cb68eac7f1365e17 Mon Sep 17 00:00:00 2001 From: Hemant Kumar Date: Wed, 7 Jun 2017 18:54:42 -0700 Subject: [PATCH 1/2] usb: core: Add support to parse config summary capability descriptors This descriptor describes the list of functions present in a given configuration. There should be one such descriptor per configuration supported by the device. The order in which these descriptors appear in the BOS descriptor reflects the order of preference of configurations as desired by the device for optimal functionality. Configuration Summary descriptors are used by Host software to decide which Configuration to set to obtain the desired functionality. Change-Id: I7ec095ce19caa690c0d3dc0fdd3add5ad37a74f3 Signed-off-by: Hemant Kumar --- drivers/usb/core/config.c | 8 ++++++++ include/linux/usb.h | 2 ++ include/uapi/linux/usb/ch9.h | 23 +++++++++++++++++++++++ 3 files changed, 33 insertions(+) diff --git a/drivers/usb/core/config.c b/drivers/usb/core/config.c index 325cbc9c35d8..b1298f093f13 100644 --- a/drivers/usb/core/config.c +++ b/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; } diff --git a/include/linux/usb.h b/include/linux/usb.h index a55f127d6836..e8b2ed4ad851 100644 --- a/include/linux/usb.h +++ b/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, diff --git a/include/uapi/linux/usb/ch9.h b/include/uapi/linux/usb/ch9.h index 779a62aafafe..d3ab3f57aa9f 100644 --- a/include/uapi/linux/usb/ch9.h +++ b/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)); /*-------------------------------------------------------------------------*/ From 58e69aad4486408aea8cffbabc4155fc85ac984c Mon Sep 17 00:00:00 2001 From: Hemant Kumar Date: Wed, 7 Jun 2017 19:08:33 -0700 Subject: [PATCH 2/2] usb: core: Add support to handle multi config audio device A USB audio class 3.0 based device may express different audio interface associations representing the same underlying hardware by using multiple USB device configuration descriptors. Using BOS configuration summary descriptor host software can choose which configuration to set. This is done by going over list of configuration summary descriptors and selecting the first available configuration supporting BADD subclass of UAC 3.0 protocol. Change-Id: I548b362437deb525f952d4450cfae7420a524c65 Signed-off-by: Hemant Kumar --- drivers/usb/core/generic.c | 38 ++++++++++++++++++++++++++++++++++++-- 1 file changed, 36 insertions(+), 2 deletions(-) diff --git a/drivers/usb/core/generic.c b/drivers/usb/core/generic.c index 358ca8dd784f..72d1109f13eb 100644 --- a/drivers/usb/core/generic.c +++ b/drivers/usb/core/generic.c @@ -19,6 +19,8 @@ #include #include +#include +#include #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));