Fixed MTP to work with TWRP

arch/powerpc/include/asm/checksum.h

@@ -0,0 +1,132 @@
+#ifndef _ASM_POWERPC_CHECKSUM_H
+#define _ASM_POWERPC_CHECKSUM_H
+#ifdef __KERNEL__
+
+/*
+ * 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 is a version of ip_compute_csum() optimized for IP headers,
+ * which always checksum on 4 octet boundaries.  ihl is the number
+ * of 32-bit words and is always >= 5.
+ */
+#ifdef CONFIG_GENERIC_CSUM
+#include <asm-generic/checksum.h>
+#else
+extern __sum16 ip_fast_csum(const void *iph, unsigned int ihl);
+
+/*
+ * computes the checksum of the TCP/UDP pseudo-header
+ * returns a 16-bit checksum, already complemented
+ */
+extern __sum16 csum_tcpudp_magic(__be32 saddr, __be32 daddr,
+					unsigned short len,
+					unsigned short proto,
+					__wsum sum);
+
+/*
+ * 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 *buff, int len, __wsum sum);
+
+/*
+ * Computes the checksum of a memory block at src, length len,
+ * and adds in "sum" (32-bit), while copying the block to dst.
+ * If an access exception occurs on src or dst, it stores -EFAULT
+ * to *src_err or *dst_err respectively (if that pointer is not
+ * NULL), and, for an error on src, zeroes the rest of dst.
+ *
+ * Like csum_partial, this must be called with even lengths,
+ * except for the last fragment.
+ */
+extern __wsum csum_partial_copy_generic(const void *src, void *dst,
+					      int len, __wsum sum,
+					      int *src_err, int *dst_err);
+
+#ifdef __powerpc64__
+#define _HAVE_ARCH_COPY_AND_CSUM_FROM_USER
+extern __wsum csum_and_copy_from_user(const void __user *src, void *dst,
+				      int len, __wsum sum, int *err_ptr);
+#define HAVE_CSUM_COPY_USER
+extern __wsum csum_and_copy_to_user(const void *src, void __user *dst,
+				    int len, __wsum sum, int *err_ptr);
+#else
+/*
+ * the same as csum_partial, but copies from src to dst while it
+ * checksums.
+ */
+#define csum_partial_copy_from_user(src, dst, len, sum, errp)   \
+        csum_partial_copy_generic((__force const void *)(src), (dst), (len), (sum), (errp), NULL)
+#endif
+
+#define csum_partial_copy_nocheck(src, dst, len, sum)   \
+        csum_partial_copy_generic((src), (dst), (len), (sum), NULL, NULL)
+
+
+/*
+ * turns a 32-bit partial checksum (e.g. from csum_partial) into a
+ * 1's complement 16-bit checksum.
+ */
+static inline __sum16 csum_fold(__wsum sum)
+{
+	unsigned int tmp;
+
+	/* swap the two 16-bit halves of sum */
+	__asm__("rlwinm %0,%1,16,0,31" : "=r" (tmp) : "r" (sum));
+	/* if there is a carry from adding the two 16-bit halves,
+	   it will carry from the lower half into the upper half,
+	   giving us the correct sum in the upper half. */
+	return (__force __sum16)(~((__force u32)sum + tmp) >> 16);
+}
+
+/*
+ * this routine is used for miscellaneous IP-like checksums, mainly
+ * in icmp.c
+ */
+static inline __sum16 ip_compute_csum(const void *buff, int len)
+{
+	return csum_fold(csum_partial(buff, len, 0));
+}
+
+static inline __wsum csum_tcpudp_nofold(__be32 saddr, __be32 daddr,
+                                     unsigned short len,
+                                     unsigned short proto,
+                                     __wsum sum)
+{
+#ifdef __powerpc64__
+	unsigned long s = (__force u32)sum;
+
+	s += (__force u32)saddr;
+	s += (__force u32)daddr;
+	s += proto + len;
+	s += (s >> 32);
+	return (__force __wsum) s;
+#else
+    __asm__("\n\
+	addc %0,%0,%1 \n\
+	adde %0,%0,%2 \n\
+	adde %0,%0,%3 \n\
+	addze %0,%0 \n\
+	"
+	: "=r" (sum)
+	: "r" (daddr), "r"(saddr), "r"(proto + len), "0"(sum));
+	return sum;
+#endif
+}
+
+#endif
+#endif /* __KERNEL__ */
+#endif