1 files changed, 117 insertions, 0 deletions
diff --git a/drivers/usb/gadget/config.c b/drivers/usb/gadget/config.c
new file mode 100644
index 00000000000..83b4866df9a
--- /dev/null
+++ b/drivers/usb/gadget/config.c
@@ -0,0 +1,117 @@
+/*
+ * usb/gadget/config.c -- simplify building config descriptors
+ *
+ * Copyright (C) 2003 David Brownell
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#include <linux/errno.h>
+#include <linux/kernel.h>
+#include <linux/list.h>
+#include <linux/string.h>
+#include <linux/device.h>
+
+#include <linux/usb_ch9.h>
+#include <linux/usb_gadget.h>
+
+
+/**
+ * usb_descriptor_fillbuf - fill buffer with descriptors
+ * @buf: Buffer to be filled
+ * @buflen: Size of buf
+ * @src: Array of descriptor pointers, terminated by null pointer.
+ *
+ * Copies descriptors into the buffer, returning the length or a
+ * negative error code if they can't all be copied.  Useful when
+ * assembling descriptors for an associated set of interfaces used
+ * as part of configuring a composite device; or in other cases where
+ * sets of descriptors need to be marshaled.
+ */
+int
+usb_descriptor_fillbuf(void *buf, unsigned buflen,
+		const struct usb_descriptor_header **src)
+{
+	u8	*dest = buf;
+
+	if (!src)
+		return -EINVAL;
+
+	/* fill buffer from src[] until null descriptor ptr */
+	for (; 0 != *src; src++) {
+		unsigned		len = (*src)->bLength;
+
+		if (len > buflen)
+			return -EINVAL;
+		memcpy(dest, *src, len);
+		buflen -= len;
+		dest += len;
+	}
+	return dest - (u8 *)buf;
+}
+
+
+/**
+ * usb_gadget_config_buf - builts a complete configuration descriptor
+ * @config: Header for the descriptor, including characteristics such
+ *	as power requirements and number of interfaces.
+ * @desc: Null-terminated vector of pointers to the descriptors (interface,
+ *	endpoint, etc) defining all functions in this device configuration.
+ * @buf: Buffer for the resulting configuration descriptor.
+ * @length: Length of buffer.  If this is not big enough to hold the
+ *	entire configuration descriptor, an error code will be returned.
+ *
+ * This copies descriptors into the response buffer, building a descriptor
+ * for that configuration.  It returns the buffer length or a negative
+ * status code.  The config.wTotalLength field is set to match the length
+ * of the result, but other descriptor fields (including power usage and
+ * interface count) must be set by the caller.
+ *
+ * Gadget drivers could use this when constructing a config descriptor
+ * in response to USB_REQ_GET_DESCRIPTOR.  They will need to patch the
+ * resulting bDescriptorType value if USB_DT_OTHER_SPEED_CONFIG is needed.
+ */
+int usb_gadget_config_buf(
+	const struct usb_config_descriptor	*config,
+	void					*buf,
+	unsigned				length,
+	const struct usb_descriptor_header	**desc
+)
+{
+	struct usb_config_descriptor		*cp = buf;
+	int					len;
+
+	/* config descriptor first */
+	if (length < USB_DT_CONFIG_SIZE || !desc)
+		return -EINVAL;
+	*cp = *config; 
+
+	/* then interface/endpoint/class/vendor/... */
+	len = usb_descriptor_fillbuf(USB_DT_CONFIG_SIZE + (u8*)buf,
+			length - USB_DT_CONFIG_SIZE, desc);
+	if (len < 0)
+		return len;
+	len += USB_DT_CONFIG_SIZE;
+	if (len > 0xffff)
+		return -EINVAL;
+
+	/* patch up the config descriptor */
+	cp->bLength = USB_DT_CONFIG_SIZE;
+	cp->bDescriptorType = USB_DT_CONFIG;
+	cp->wTotalLength = cpu_to_le16(len);
+	cp->bmAttributes |= USB_CONFIG_ATT_ONE;
+	return len;
+}
+