/* SPDX-License-Identifier: GPL-2.0-only */
/*
 * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
 *
 * Joern Rennecke  <joern.rennecke@embecosm.com>: Jan 2012
 *  -Insn Scheduling improvements to csum core routines.
 *      = csum_fold( ) largely derived from ARM version.
 *      = ip_fast_cum( ) to have module scheduling
 *  -gcc 4.4.x broke networking. Alias analysis needed to be primed.
 *   worked around by adding memory clobber to ip_fast_csum( )
 *
 * vineetg: May 2010
 *  -Rewrote ip_fast_cscum( ) and csum_fold( ) with fast inline asm
 */

#ifndef _ASM_ARC_CHECKSUM_H
#define _ASM_ARC_CHECKSUM_H

/*
 *      Fold a partial checksum
 *
 *  The 2 swords comprising the 32bit sum are added, any carry to 16th bit
 *  added back and final sword result inverted.
 */
static inline __sum16 csum_fold(__wsum s)
{
        unsigned int r = s << 16 | s >> 16;     /* ror */
        s = ~s;
        s -= r;
        return s >> 16;
}

/*
 *      This is a version of ip_compute_csum() optimized for IP headers,
 *      which always checksum on 4 octet boundaries.
 */
static inline __sum16
ip_fast_csum(const void *iph, unsigned int ihl)
{
        const void *ptr = iph;
        unsigned int tmp, tmp2, sum;

        __asm__(
        "       ld.ab  %0, [%3, 4]              \n"
        "       ld.ab  %2, [%3, 4]              \n"
        "       sub    %1, %4, 2                \n"
        "       lsr.f  lp_count, %1, 1          \n"
        "       bcc    0f                       \n"
        "       add.f  %0, %0, %2               \n"
        "       ld.ab  %2, [%3, 4]              \n"
        "0:     lp     1f                       \n"
        "       ld.ab  %1, [%3, 4]              \n"
        "       adc.f  %0, %0, %2               \n"
        "       ld.ab  %2, [%3, 4]              \n"
        "       adc.f  %0, %0, %1               \n"
        "1:     adc.f  %0, %0, %2               \n"
        "       add.cs %0,%0,1                  \n"
        : "=&r"(sum), "=r"(tmp), "=&r"(tmp2), "+&r" (ptr)
        : "r"(ihl)
        : "cc", "lp_count", "memory");

        return csum_fold(sum);
}

/*
 * TCP pseudo Header is 12 bytes:
 * SA [4], DA [4], zeroes [1], Proto[1], TCP Seg(hdr+data) Len [2]
 */
static inline __wsum
csum_tcpudp_nofold(__be32 saddr, __be32 daddr, __u32 len,
                   __u8 proto, __wsum sum)
{
        __asm__ __volatile__(
        "       add.f %0, %0, %1        \n"
        "       adc.f %0, %0, %2        \n"
        "       adc.f %0, %0, %3        \n"
        "       adc.f %0, %0, %4        \n"
        "       adc   %0, %0, 0         \n"
        : "+&r"(sum)
        : "r"(saddr), "r"(daddr),
#ifdef CONFIG_CPU_BIG_ENDIAN
          "r"(len),
#else
          "r"(len << 8),
#endif
          "r"(htons(proto))
        : "cc");

        return sum;
}

#define csum_fold csum_fold
#define ip_fast_csum ip_fast_csum
#define csum_tcpudp_nofold csum_tcpudp_nofold

#include <asm-generic/checksum.h>

#endif /* _ASM_ARC_CHECKSUM_H */