/*
* Copyright (C) 2004-2006 Atmel Corporation
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#ifndef __ASM_AVR32_CHECKSUM_H
#define __ASM_AVR32_CHECKSUM_H
/*
* computes the checksum of a memory block at buff, length len,
* and adds in "sum" (32-bit)
*
* returns a 32-bit number suitable for feeding into itself
* or csum_tcpudp_magic
*
* this function must be called with even lengths, except
* for the last fragment, which may be odd
*
* it's best to have buff aligned on a 32-bit boundary
*/
unsigned int csum_partial(const unsigned char * buff, int len,
unsigned int sum);
/*
* the same as csum_partial, but copies from src while it
* checksums, and handles user-space pointer exceptions correctly, when needed.
*
* here even more important to align src and dst on a 32-bit (or even
* better 64-bit) boundary
*/
unsigned int csum_partial_copy_generic(const char *src, char *dst, int len,
int sum, int *src_err_ptr,
int *dst_err_ptr);
/*
* Note: when you get a NULL pointer exception here this means someone
* passed in an incorrect kernel address to one of these functions.
*
* If you use these functions directly please don't forget the
* verify_area().
*/
static inline
unsigned int csum_partial_copy_nocheck(const char *src, char *dst,
int len, int sum)
{
return csum_partial_copy_generic(src, dst, len, sum, NULL, NULL);
}
static inline
unsigned int csum_partial_copy_from_user (const char __user *src, char *dst,
int len, int sum, int *err_ptr)
{
return csum_partial_copy_generic((const char __force *)src, dst, len,
sum, err_ptr, NULL);
}
/*
* This is a version of ip_compute_csum() optimized for IP headers,
* which always checksum on 4 octet boundaries.
*/
static inline unsigned short ip_fast_csum(unsigned char *iph,
unsigned int ihl)
{
unsigned int sum, tmp;
__asm__ __volatile__(
" ld.w %0, %1++\n"
" ld.w %3, %1++\n"
" sub %2, 4\n"
" add %0, %3\n"
" ld.w %3, %1++\n"
" adc %0, %0, %3\n"
" ld.w %3, %1++\n"
" adc %0, %0, %3\n"
" acr %0\n"
"1: ld.w %3, %1++\n"
" add %0, %3\n"
" acr %0\n"
" sub %2, 1\n"
" brne 1b\n"
" lsl %3, %0, 16\n"
" andl %0, 0\n"
" mov %2, 0xffff\n"
" add %0, %3\n"
" adc %0, %0, %2\n"
" com %0\n"
" lsr %0, 16\n"
: "=r"(sum), "=r"(iph), "=r"(ihl), "=r"(tmp)
: "1"(iph), "2"(ihl)
: "memory", "cc");
return sum;
}
/*
* Fold a partial checksum
*/
static inline unsigned int csum_fold(unsigned int sum)
{
unsigned int tmp;
asm(" bfextu %1, %0, 0, 16\n"
" lsr %0, 16\n"
" add %0, %1\n"
" bfextu %1, %0, 16, 16\n"
" add %0, %1"
: "=&r"(sum), "=&r"(tmp)
: "0"(sum));
return ~sum;
}
static inline unsigned long csum_tcpudp_nofold(unsigned long saddr,
unsigned long daddr,
unsigned short len,
unsigned short proto,
unsigned int sum)
{
asm(" add %0, %1\n"
" adc %0, %0, %2\n"
" adc %0, %0, %3\n"
" acr %0"
: "=r"(sum)
: "r"(daddr), "r"(saddr), "r"(ntohs(len) | (proto << 16)),
"0"(sum)
: "cc");
return sum;
}
/*
* computes the checksum of the TCP/UDP pseudo-header
* returns a 16-bit checksum, already complemented
*/
static inline unsigned short int csum_tcpudp_magic(unsigned long saddr,
unsigned long daddr,
unsigned short len,
unsigned short proto,
unsigned int sum)
{
return csum_fold(csum_tcpudp_nofold(saddr,daddr,len,proto,sum));
}
/*
* this routine is used for miscellaneous IP-like checksums, mainly
* in icmp.c
*/
static inline unsigned short ip_compute_csum(unsigned char * buff, int len)
{
return csum_fold(csum_partial(buff, len, 0));
}
#endif /* __ASM_AVR32_CHECKSUM_H */
