/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _PARISC_CHECKSUM_H
#define _PARISC_CHECKSUM_H

#include <linux/in6.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
 */
extern __wsum csum_partial(const void *, int, __wsum);

/*
 * The same as csum_partial, but copies from src while it checksums.
 *
 * Here even more important to align src and dst on a 32-bit (or even
 * better 64-bit) boundary
 */
extern __wsum csum_partial_copy_nocheck(const void *, void *, int, __wsum);

/*
 * this is a new version of the above that records errors it finds in *errp,
 * but continues and zeros the rest of the buffer.
 */
extern __wsum csum_partial_copy_from_user(const void __user *src,
                void *dst, int len, __wsum sum, int *errp);

/*
 *      Optimized for IP headers, which always checksum on 4 octet boundaries.
 *
 *      Written by Randolph Chung <tausq@debian.org>, and then mucked with by
 *      LaMont Jones <lamont@debian.org>
 */
static inline __sum16 ip_fast_csum(const void *iph, unsigned int ihl)
{
        unsigned int sum;

        __asm__ __volatile__ (
"       ldws,ma         4(%1), %0\n"
"       addib,<=        -4, %2, 2f\n"
"\n"
"       ldws            4(%1), %%r20\n"
"       ldws            8(%1), %%r21\n"
"       add             %0, %%r20, %0\n"
"       ldws,ma         12(%1), %%r19\n"
"       addc            %0, %%r21, %0\n"
"       addc            %0, %%r19, %0\n"
"1:     ldws,ma         4(%1), %%r19\n"
"       addib,<         0, %2, 1b\n"
"       addc            %0, %%r19, %0\n"
"\n"
"       extru           %0, 31, 16, %%r20\n"
"       extru           %0, 15, 16, %%r21\n"
"       addc            %%r20, %%r21, %0\n"
"       extru           %0, 15, 16, %%r21\n"
"       add             %0, %%r21, %0\n"
"       subi            -1, %0, %0\n"
"2:\n"
        : "=r" (sum), "=r" (iph), "=r" (ihl)
        : "1" (iph), "2" (ihl)
        : "r19", "r20", "r21", "memory");

        return (__force __sum16)sum;
}

/*
 *      Fold a partial checksum
 */
static inline __sum16 csum_fold(__wsum csum)
{
        u32 sum = (__force u32)csum;
        /* add the swapped two 16-bit halves of sum,
           a possible carry from adding the two 16-bit halves,
           will carry from the lower half into the upper half,
           giving us the correct sum in the upper half. */
        sum += (sum << 16) + (sum >> 16);
        return (__force __sum16)(~sum >> 16);
}
 
static inline __wsum csum_tcpudp_nofold(__be32 saddr, __be32 daddr,
                                        __u32 len, __u8 proto,
                                        __wsum sum)
{
        __asm__(
        "       add  %1, %0, %0\n"
        "       addc %2, %0, %0\n"
        "       addc %3, %0, %0\n"
        "       addc %%r0, %0, %0\n"
                : "=r" (sum)
                : "r" (daddr), "r"(saddr), "r"(proto+len), "0"(sum));
        return sum;
}

/*
 * computes the checksum of the TCP/UDP pseudo-header
 * returns a 16-bit checksum, already complemented
 */
static inline __sum16 csum_tcpudp_magic(__be32 saddr, __be32 daddr,
                                        __u32 len, __u8 proto,
                                        __wsum 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 __sum16 ip_compute_csum(const void *buf, int len)
{
         return csum_fold (csum_partial(buf, len, 0));
}


#define _HAVE_ARCH_IPV6_CSUM
static __inline__ __sum16 csum_ipv6_magic(const struct in6_addr *saddr,
                                          const struct in6_addr *daddr,
                                          __u32 len, __u8 proto,
                                          __wsum sum)
{
        __asm__ __volatile__ (

#if BITS_PER_LONG > 32

        /*
        ** We can execute two loads and two adds per cycle on PA 8000.
        ** But add insn's get serialized waiting for the carry bit.
        ** Try to keep 4 registers with "live" values ahead of the ALU.
        */

"       ldd,ma          8(%1), %%r19\n" /* get 1st saddr word */
"       ldd,ma          8(%2), %%r20\n" /* get 1st daddr word */
"       add             %8, %3, %3\n"/* add 16-bit proto + len */
"       add             %%r19, %0, %0\n"
"       ldd,ma          8(%1), %%r21\n" /* 2cd saddr */
"       ldd,ma          8(%2), %%r22\n" /* 2cd daddr */
"       add,dc          %%r20, %0, %0\n"
"       add,dc          %%r21, %0, %0\n"
"       add,dc          %%r22, %0, %0\n"
"       add,dc          %3, %0, %0\n"  /* fold in proto+len | carry bit */
"       extrd,u         %0, 31, 32, %%r19\n"    /* copy upper half down */
"       depdi           0, 31, 32, %0\n"        /* clear upper half */
"       add             %%r19, %0, %0\n"        /* fold into 32-bits */
"       addc            0, %0, %0\n"            /* add carry */

#else

        /*
        ** For PA 1.x, the insn order doesn't matter as much.
        ** Insn stream is serialized on the carry bit here too.
        ** result from the previous operation (eg r0 + x)
        */

"       ldw,ma          4(%1), %%r19\n" /* get 1st saddr word */
"       ldw,ma          4(%2), %%r20\n" /* get 1st daddr word */
"       add             %8, %3, %3\n"   /* add 16-bit proto + len */
"       add             %%r19, %0, %0\n"
"       ldw,ma          4(%1), %%r21\n" /* 2cd saddr */
"       addc            %%r20, %0, %0\n"
"       ldw,ma          4(%2), %%r22\n" /* 2cd daddr */
"       addc            %%r21, %0, %0\n"
"       ldw,ma          4(%1), %%r19\n" /* 3rd saddr */
"       addc            %%r22, %0, %0\n"
"       ldw,ma          4(%2), %%r20\n" /* 3rd daddr */
"       addc            %%r19, %0, %0\n"
"       ldw,ma          4(%1), %%r21\n" /* 4th saddr */
"       addc            %%r20, %0, %0\n"
"       ldw,ma          4(%2), %%r22\n" /* 4th daddr */
"       addc            %%r21, %0, %0\n"
"       addc            %%r22, %0, %0\n"
"       addc            %3, %0, %0\n"   /* fold in proto+len, catch carry */

#endif
        : "=r" (sum), "=r" (saddr), "=r" (daddr), "=r" (len)
        : "0" (sum), "1" (saddr), "2" (daddr), "3" (len), "r" (proto)
        : "r19", "r20", "r21", "r22", "memory");
        return csum_fold(sum);
}

/* 
 *      Copy and checksum to user
 */
#define HAVE_CSUM_COPY_USER
static __inline__ __wsum csum_and_copy_to_user(const void *src,
                                                      void __user *dst,
                                                      int len, __wsum sum,
                                                      int *err_ptr)
{
        /* code stolen from include/asm-mips64 */
        sum = csum_partial(src, len, sum);
         
        if (copy_to_user(dst, src, len)) {
                *err_ptr = -EFAULT;
                return (__force __wsum)-1;
        }

        return sum;
}

#endif