diff options
| -rw-r--r-- | drivers/usb/gadget/composite.c | 29 | ||||
| -rw-r--r-- | include/linux/usb/composite.h | 11 |
2 files changed, 40 insertions, 0 deletions
diff --git a/drivers/usb/gadget/composite.c b/drivers/usb/gadget/composite.c index 8060de6562cd..2f87b1697bf5 100644 --- a/drivers/usb/gadget/composite.c +++ b/drivers/usb/gadget/composite.c @@ -21,6 +21,22 @@ #include <linux/usb/composite.h> #include <asm/unaligned.h> +/** + * struct usb_os_string - represents OS String to be reported by a gadget + * @bLength: total length of the entire descritor, always 0x12 + * @bDescriptorType: USB_DT_STRING + * @qwSignature: the OS String proper + * @bMS_VendorCode: code used by the host for subsequent requests + * @bPad: not used, must be zero + */ +struct usb_os_string { + __u8 bLength; + __u8 bDescriptorType; + __u8 qwSignature[OS_STRING_QW_SIGN_LEN]; + __u8 bMS_VendorCode; + __u8 bPad; +} __packed; + /* * The code in this file is utility code, used to build a gadget driver * from one or more "function" drivers, one or more "configuration" @@ -961,6 +977,19 @@ static int get_string(struct usb_composite_dev *cdev, return s->bLength; } + if (cdev->use_os_string && language == 0 && id == OS_STRING_IDX) { + struct usb_os_string *b = buf; + b->bLength = sizeof(*b); + b->bDescriptorType = USB_DT_STRING; + compiletime_assert( + sizeof(b->qwSignature) == sizeof(cdev->qw_sign), + "qwSignature size must be equal to qw_sign"); + memcpy(&b->qwSignature, cdev->qw_sign, sizeof(b->qwSignature)); + b->bMS_VendorCode = cdev->b_vendor_code; + b->bPad = 0; + return sizeof(*b); + } + list_for_each_entry(uc, &cdev->gstrings, list) { struct usb_gadget_strings **sp; diff --git a/include/linux/usb/composite.h b/include/linux/usb/composite.h index d3ca3b53837c..7d29ee9363e8 100644 --- a/include/linux/usb/composite.h +++ b/include/linux/usb/composite.h @@ -335,11 +335,17 @@ static inline struct usb_composite_driver *to_cdriver( return container_of(gdrv, struct usb_composite_driver, gadget_driver); } +#define OS_STRING_QW_SIGN_LEN 14 +#define OS_STRING_IDX 0xEE + /** * struct usb_composite_device - represents one composite usb gadget * @gadget: read-only, abstracts the gadget's usb peripheral controller * @req: used for control responses; buffer is pre-allocated * @config: the currently active configuration + * @qw_sign: qwSignature part of the OS string + * @b_vendor_code: bMS_VendorCode part of the OS string + * @use_os_string: false by default, interested gadgets set it * * One of these devices is allocated and initialized before the * associated device driver's bind() is called. @@ -372,6 +378,11 @@ struct usb_composite_dev { struct usb_configuration *config; + /* OS String is a custom (yet popular) extension to the USB standard. */ + u8 qw_sign[OS_STRING_QW_SIGN_LEN]; + u8 b_vendor_code; + unsigned int use_os_string:1; + /* private: */ /* internals */ unsigned int suspended:1; |