[PATCH] RFT: mips: implement __udivdi3

[Linus Walleij]

Squashfs wasn't compiling because the lldiv() directives
turn into __udivdi3 and we are using private libgcc.
This is just copied from the Linux kernel v6.6-rc1
arch/mips/include/asm/div64.h and then adjusted for
U-Boot.

After this squashfs compiles for MIPS.

Cc: Daniel Schwierzeck <daniel.schwierzeck at gmail.com>
Cc: Mauro Condarelli <mc5686 at mclink.it>
Cc: Ralf Baechle <ralf at linux-mips.org>
Signed-off-by: Linus Walleij <linus.walleij at linaro.org>
---
I can't test this because it didn't work for MTD devices
as I had expected, but I saw Mauro had this problem
before so I think I might have fixed it. I better put
the patch out there rather than let it sit on my drive.
---
 arch/mips/lib/Makefile  |  2 +-
 arch/mips/lib/udivdi3.c | 86 +++++++++++++++++++++++++++++++++++++++++
 2 files changed, 87 insertions(+), 1 deletion(-)
 create mode 100644 arch/mips/lib/udivdi3.c

diff --git a/arch/mips/lib/Makefile b/arch/mips/lib/Makefile
index 9ee1fcb5c702..1621cc9a1ff9 100644
--- a/arch/mips/lib/Makefile
+++ b/arch/mips/lib/Makefile
@@ -14,4 +14,4 @@ obj-$(CONFIG_CMD_BOOTM) += bootm.o
 obj-$(CONFIG_CMD_GO) += boot.o
 obj-$(CONFIG_SPL_BUILD) += spl.o
 
-lib-$(CONFIG_USE_PRIVATE_LIBGCC) += ashldi3.o ashrdi3.o lshrdi3.o
+lib-$(CONFIG_USE_PRIVATE_LIBGCC) += ashldi3.o ashrdi3.o lshrdi3.o udivdi3.o
diff --git a/arch/mips/lib/udivdi3.c b/arch/mips/lib/udivdi3.c
new file mode 100644
index 000000000000..6a4ee5fa46ab
--- /dev/null
+++ b/arch/mips/lib/udivdi3.c
@@ -0,0 +1,86 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2000, 2004, 2021  Maciej W. Rozycki
+ * Copyright (C) 2003, 07 Ralf Baechle (ralf at linux-mips.org)
+ */
+
+#include "libgcc.h"
+
+/*
+ * No traps on overflows for any of these...
+ */
+
+#define do_div64_32(res, high, low, base) ({				\
+	unsigned long __cf, __tmp, __tmp2, __i;				\
+	unsigned long __quot32, __mod32;				\
+									\
+	__asm__(							\
+	"	.set	push					\n"	\
+	"	.set	noat					\n"	\
+	"	.set	noreorder				\n"	\
+	"	move	%2, $0					\n"	\
+	"	move	%3, $0					\n"	\
+	"	b	1f					\n"	\
+	"	 li	%4, 0x21				\n"	\
+	"0:							\n"	\
+	"	sll	$1, %0, 0x1				\n"	\
+	"	srl	%3, %0, 0x1f				\n"	\
+	"	or	%0, $1, %5				\n"	\
+	"	sll	%1, %1, 0x1				\n"	\
+	"	sll	%2, %2, 0x1				\n"	\
+	"1:							\n"	\
+	"	bnez	%3, 2f					\n"	\
+	"	 sltu	%5, %0, %z6				\n"	\
+	"	bnez	%5, 3f					\n"	\
+	"2:							\n"	\
+	"	 addiu	%4, %4, -1				\n"	\
+	"	subu	%0, %0, %z6				\n"	\
+	"	addiu	%2, %2, 1				\n"	\
+	"3:							\n"	\
+	"	bnez	%4, 0b					\n"	\
+	"	 srl	%5, %1, 0x1f				\n"	\
+	"	.set	pop"						\
+	: "=&r" (__mod32), "=&r" (__tmp),				\
+	  "=&r" (__quot32), "=&r" (__cf),				\
+	  "=&r" (__i), "=&r" (__tmp2)					\
+	: "Jr" (base), "0" (high), "1" (low));				\
+									\
+	(res) = __quot32;						\
+	__mod32;							\
+})
+
+#define __div64_32(n, base) ({						\
+	unsigned long __upper, __low, __high, __radix;			\
+	unsigned long long __quot;					\
+	unsigned long long __div;					\
+	unsigned long __mod;						\
+									\
+	__div = (*n);							\
+	__radix = (base);						\
+									\
+	__high = __div >> 32;						\
+	__low = __div;							\
+									\
+	if (__high < __radix) {						\
+		__upper = __high;					\
+		__high = 0;						\
+	} else {							\
+		__upper = __high % __radix;				\
+		__high /= __radix;					\
+	}								\
+									\
+	__mod = do_div64_32(__low, __upper, __low, __radix);		\
+									\
+	__quot = __high;						\
+	__quot = __quot << 32 | __low;					\
+	(*n) = __quot;							\
+	__mod;								\
+})
+
+long long __udivdi3(long long u, word_type b)
+{
+	long long ret = u;
+
+	__div64_32(&ret, b);
+	return ret;
+}
-- 
2.41.0