120 lines
		
	
	
		
			3.8 KiB
		
	
	
	
		
			C
		
	
	
	
			
		
		
	
	
			120 lines
		
	
	
		
			3.8 KiB
		
	
	
	
		
			C
		
	
	
	
/*
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 * usb/gadget/config.c -- simplify building config descriptors
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 *
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 * Copyright (C) 2003 David Brownell
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 *
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 * This program is free software; you can redistribute it and/or modify
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 * it under the terms of the GNU General Public License as published by
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 * the Free Software Foundation; either version 2 of the License, or
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 * (at your option) any later version.
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 *
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 * This program is distributed in the hope that it will be useful,
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 * but WITHOUT ANY WARRANTY; without even the implied warranty of
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 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
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 * GNU General Public License for more details.
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 *
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 * You should have received a copy of the GNU General Public License
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 * along with this program; if not, write to the Free Software
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 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
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 *
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 * Ported to U-boot by: Thomas Smits <ts.smits@gmail.com> and
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 *                      Remy Bohmer <linux@bohmer.net>
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 */
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#include <common.h>
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#include <asm/errno.h>
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#include <linux/list.h>
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#include <linux/string.h>
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#include <linux/usb/ch9.h>
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#include <linux/usb/gadget.h>
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/**
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 * usb_descriptor_fillbuf - fill buffer with descriptors
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 * @buf: Buffer to be filled
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 * @buflen: Size of buf
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 * @src: Array of descriptor pointers, terminated by null pointer.
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 *
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 * Copies descriptors into the buffer, returning the length or a
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 * negative error code if they can't all be copied.  Useful when
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 * assembling descriptors for an associated set of interfaces used
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 * as part of configuring a composite device; or in other cases where
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 * sets of descriptors need to be marshaled.
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 */
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int
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usb_descriptor_fillbuf(void *buf, unsigned buflen,
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		const struct usb_descriptor_header **src)
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{
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	u8	*dest = buf;
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	if (!src)
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		return -EINVAL;
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	/* fill buffer from src[] until null descriptor ptr */
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	for (; NULL != *src; src++) {
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		unsigned		len = (*src)->bLength;
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		if (len > buflen)
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			return -EINVAL;
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		memcpy(dest, *src, len);
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		buflen -= len;
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		dest += len;
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	}
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	return dest - (u8 *)buf;
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}
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/**
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 * usb_gadget_config_buf - builts a complete configuration descriptor
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 * @config: Header for the descriptor, including characteristics such
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 *	as power requirements and number of interfaces.
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 * @desc: Null-terminated vector of pointers to the descriptors (interface,
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 *	endpoint, etc) defining all functions in this device configuration.
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 * @buf: Buffer for the resulting configuration descriptor.
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 * @length: Length of buffer.  If this is not big enough to hold the
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 *	entire configuration descriptor, an error code will be returned.
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 *
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 * This copies descriptors into the response buffer, building a descriptor
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 * for that configuration.  It returns the buffer length or a negative
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 * status code.  The config.wTotalLength field is set to match the length
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 * of the result, but other descriptor fields (including power usage and
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 * interface count) must be set by the caller.
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 *
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 * Gadget drivers could use this when constructing a config descriptor
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 * in response to USB_REQ_GET_DESCRIPTOR.  They will need to patch the
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 * resulting bDescriptorType value if USB_DT_OTHER_SPEED_CONFIG is needed.
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 */
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int usb_gadget_config_buf(
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	const struct usb_config_descriptor	*config,
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	void					*buf,
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	unsigned				length,
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	const struct usb_descriptor_header	**desc
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)
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{
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	struct usb_config_descriptor		*cp = buf;
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	int					len;
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	/* config descriptor first */
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	if (length < USB_DT_CONFIG_SIZE || !desc)
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		return -EINVAL;
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	*cp = *config;
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	/* then interface/endpoint/class/vendor/... */
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	len = usb_descriptor_fillbuf(USB_DT_CONFIG_SIZE + (u8 *)buf,
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			length - USB_DT_CONFIG_SIZE, desc);
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	if (len < 0)
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		return len;
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	len += USB_DT_CONFIG_SIZE;
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	if (len > 0xffff)
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		return -EINVAL;
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	/* patch up the config descriptor */
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	cp->bLength = USB_DT_CONFIG_SIZE;
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	cp->bDescriptorType = USB_DT_CONFIG;
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	cp->wTotalLength = cpu_to_le16(len);
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	cp->bmAttributes |= USB_CONFIG_ATT_ONE;
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	return len;
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}
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