1 files changed, 139 insertions, 0 deletions
diff --git a/arch/arm/lib/csumpartial.S b/arch/arm/lib/csumpartial.S
new file mode 100644
index 000000000..87c9471be
--- /dev/null
+++ b/arch/arm/lib/csumpartial.S
@@ -0,0 +1,139 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ *  linux/arch/arm/lib/csumpartial.S
+ *
+ *  Copyright (C) 1995-1998 Russell King
+ */
+#include <linux/linkage.h>
+#include <asm/assembler.h>
+
+		.text
+
+/*
+ * Function: __u32 csum_partial(const char *src, int len, __u32 sum)
+ * Params  : r0 = buffer, r1 = len, r2 = checksum
+ * Returns : r0 = new checksum
+ */
+
+buf	.req	r0
+len	.req	r1
+sum	.req	r2
+td0	.req	r3
+td1	.req	r4	@ save before use
+td2	.req	r5	@ save before use
+td3	.req	lr
+
+.Lzero:		mov	r0, sum
+		add	sp, sp, #4
+		ldr	pc, [sp], #4
+
+		/*
+		 * Handle 0 to 7 bytes, with any alignment of source and
+		 * destination pointers.  Note that when we get here, C = 0
+		 */
+.Lless8:		teq	len, #0			@ check for zero count
+		beq	.Lzero
+
+		/* we must have at least one byte. */
+		tst	buf, #1			@ odd address?
+		movne	sum, sum, ror #8
+		ldrbne	td0, [buf], #1
+		subne	len, len, #1
+		adcsne	sum, sum, td0, put_byte_1
+
+.Lless4:		tst	len, #6
+		beq	.Lless8_byte
+
+		/* we are now half-word aligned */
+
+.Lless8_wordlp:
+#if __LINUX_ARM_ARCH__ >= 4
+		ldrh	td0, [buf], #2
+		sub	len, len, #2
+#else
+		ldrb	td0, [buf], #1
+		ldrb	td3, [buf], #1
+		sub	len, len, #2
+#ifndef __ARMEB__
+		orr	td0, td0, td3, lsl #8
+#else
+		orr	td0, td3, td0, lsl #8
+#endif
+#endif
+		adcs	sum, sum, td0
+		tst	len, #6
+		bne	.Lless8_wordlp
+
+.Lless8_byte:	tst	len, #1			@ odd number of bytes
+		ldrbne	td0, [buf], #1		@ include last byte
+		adcsne	sum, sum, td0, put_byte_0	@ update checksum
+
+.Ldone:		adc	r0, sum, #0		@ collect up the last carry
+		ldr	td0, [sp], #4
+		tst	td0, #1			@ check buffer alignment
+		movne	r0, r0, ror #8		@ rotate checksum by 8 bits
+		ldr	pc, [sp], #4		@ return
+
+.Lnot_aligned:	tst	buf, #1			@ odd address
+		ldrbne	td0, [buf], #1		@ make even
+		subne	len, len, #1
+		adcsne	sum, sum, td0, put_byte_1	@ update checksum
+
+		tst	buf, #2			@ 32-bit aligned?
+#if __LINUX_ARM_ARCH__ >= 4
+		ldrhne	td0, [buf], #2		@ make 32-bit aligned
+		subne	len, len, #2
+#else
+		ldrbne	td0, [buf], #1
+		ldrbne	ip, [buf], #1
+		subne	len, len, #2
+#ifndef __ARMEB__
+		orrne	td0, td0, ip, lsl #8
+#else
+		orrne	td0, ip, td0, lsl #8
+#endif
+#endif
+		adcsne	sum, sum, td0		@ update checksum
+		ret	lr
+
+ENTRY(csum_partial)
+		stmfd	sp!, {buf, lr}
+		cmp	len, #8			@ Ensure that we have at least
+		blo	.Lless8			@ 8 bytes to copy.
+
+		tst	buf, #1
+		movne	sum, sum, ror #8
+
+		adds	sum, sum, #0		@ C = 0
+		tst	buf, #3			@ Test destination alignment
+		blne	.Lnot_aligned		@ align destination, return here
+
+1:		bics	ip, len, #31
+		beq	3f
+
+		stmfd	sp!, {r4 - r5}
+2:		ldmia	buf!, {td0, td1, td2, td3}
+		adcs	sum, sum, td0
+		adcs	sum, sum, td1
+		adcs	sum, sum, td2
+		adcs	sum, sum, td3
+		ldmia	buf!, {td0, td1, td2, td3}
+		adcs	sum, sum, td0
+		adcs	sum, sum, td1
+		adcs	sum, sum, td2
+		adcs	sum, sum, td3
+		sub	ip, ip, #32
+		teq	ip, #0
+		bne	2b
+		ldmfd	sp!, {r4 - r5}
+
+3:		tst	len, #0x1c		@ should not change C
+		beq	.Lless4
+
+4:		ldr	td0, [buf], #4
+		sub	len, len, #4
+		adcs	sum, sum, td0
+		tst	len, #0x1c
+		bne	4b
+		b	.Lless4
+ENDPROC(csum_partial)