The SuperspeedPlus Device Capability Descriptor has a variable size
depending on the number of sublink speed attributes.
This patch adds a macro to calculate that size. The macro takes one
argument, the Sublink Speed Attribute Count (SSAC) as reported by the
descriptor in bmAttributes[4:0].
See USB 3.1 9.6.2.5, Table 9-19.
Signed-off-by: John Youn <johnyoun@xxxxxxxxxxxx>
---
include/uapi/linux/usb/ch9.h | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/include/uapi/linux/usb/ch9.h b/include/uapi/linux/usb/ch9.h
index 779a62a..9ffaaaa 100644
--- a/include/uapi/linux/usb/ch9.h
+++ b/include/uapi/linux/usb/ch9.h
@@ -894,6 +894,11 @@ struct usb_ssp_cap_descriptor {
#define USB_SSP_SUBLINK_SPEED_LSM (0xff << 16) /* Lanespeed mantissa */
} __attribute__((packed));
+/*
+ * The size of the descriptor for the Sublink Speed Attribute Count
+ * (SSAC) specified in bmAttributes[4:0].
+ */
+#define USB_DT_USB_SSP_CAP_SIZE(ssac) (16 + ssac * 4)
/*-------------------------------------------------------------------------*/
--
2.6.3
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