dm: mips: Import libgcc components from Linux

Import ashldr3, ashrdi3 and lshrdi3 to squash possible libgcc fp mismatch,
resulting in the following warning:

mips-linux-gnu-ld: Warning: /usr/lib/gcc/mips-linux-gnu/4.7/libgcc.a(_lshrdi3.o) uses hard float, u-boot uses soft float
mips-linux-gnu-ld: Warning: /usr/lib/gcc/mips-linux-gnu/4.7/libgcc.a(_ashldi3.o) uses hard float, u-boot uses soft float

Imported from Linux (linux-next 20120723) as of commit:

commit 72fbfb260197a52c2bc2583f3e8f15d261d0f924
Author: Ralf Baechle <ralf@linux-mips.org>
Date:   Wed Jun 7 13:25:37 2006 +0100

    [MIPS] Fix optimization for size build.

    It took a while longer than on other architectures but gcc has finally
    started to strike us as well ...

    This also fixes the damage by 6edfba1b33c701108717f4e036320fc39abe1912.

    Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Daniel Schwierzeck <daniel.schwierzeck@googlemail.com>
[<daniel.schwierzeck@gmail.com>: removed USE_PRIVATE_LIBGCC = yes]
Signed-off-by: Daniel Schwierzeck <daniel.schwierzeck@gmail.com>

arch/mips/lib/Makefile

@@ -25,6 +25,13 @@ include $(TOPDIR)/config.mk
 
 LIB	= $(obj)lib$(ARCH).o
 
+## Build a couple of necessary functions into a private libgcc
+LIBGCC	= $(obj)libgcc.o
+GLSOBJS	+= ashldi3.o
+GLSOBJS	+= ashrdi3.o
+GLSOBJS	+= lshrdi3.o
+LGOBJS	:= $(addprefix $(obj),$(GLSOBJS))
+
 SOBJS-y	+=
 
 COBJS-y	+= board.o
@@ -37,9 +44,22 @@ endif
 SRCS	:= $(SOBJS-y:.o=.S) $(COBJS-y:.o=.c)
 OBJS	:= $(addprefix $(obj),$(SOBJS-y) $(COBJS-y))
 
+# Always build libmips.o
+TARGETS	:= $(LIB)
+
+# Build private libgcc only when asked for
+ifdef USE_PRIVATE_LIBGCC
+TARGETS	+= $(LIBGCC)
+endif
+
+all:	$(TARGETS)
+
 $(LIB):	$(obj).depend $(OBJS)
 	$(call cmd_link_o_target, $(OBJS))
 
+$(LIBGCC): $(obj).depend $(LGOBJS)
+	$(call cmd_link_o_target, $(LGOBJS))
+
 #########################################################################
 
 # defines $(obj).depend target

arch/mips/lib/ashldi3.c

@@ -0,0 +1,25 @@
+#include "libgcc.h"
+
+long long __ashldi3(long long u, word_type b)
+{
+	DWunion uu, w;
+	word_type bm;
+
+	if (b == 0)
+		return u;
+
+	uu.ll = u;
+	bm = 32 - b;
+
+	if (bm <= 0) {
+		w.s.low = 0;
+		w.s.high = (unsigned int) uu.s.low << -bm;
+	} else {
+		const unsigned int carries = (unsigned int) uu.s.low >> bm;
+
+		w.s.low = (unsigned int) uu.s.low << b;
+		w.s.high = ((unsigned int) uu.s.high << b) | carries;
+	}
+
+	return w.ll;
+}

arch/mips/lib/ashrdi3.c

@@ -0,0 +1,27 @@
+#include "libgcc.h"
+
+long long __ashrdi3(long long u, word_type b)
+{
+	DWunion uu, w;
+	word_type bm;
+
+	if (b == 0)
+		return u;
+
+	uu.ll = u;
+	bm = 32 - b;
+
+	if (bm <= 0) {
+		/* w.s.high = 1..1 or 0..0 */
+		w.s.high =
+		    uu.s.high >> 31;
+		w.s.low = uu.s.high >> -bm;
+	} else {
+		const unsigned int carries = (unsigned int) uu.s.high << bm;
+
+		w.s.high = uu.s.high >> b;
+		w.s.low = ((unsigned int) uu.s.low >> b) | carries;
+	}
+
+	return w.ll;
+}

arch/mips/lib/libgcc.h

@@ -0,0 +1,25 @@
+#ifndef __ASM_LIBGCC_H
+#define __ASM_LIBGCC_H
+
+#include <asm/byteorder.h>
+
+typedef int word_type __attribute__ ((mode (__word__)));
+
+#ifdef __BIG_ENDIAN
+struct DWstruct {
+	int high, low;
+};
+#elif defined(__LITTLE_ENDIAN)
+struct DWstruct {
+	int low, high;
+};
+#else
+#error I feel sick.
+#endif
+
+typedef union {
+	struct DWstruct s;
+	long long ll;
+} DWunion;
+
+#endif /* __ASM_LIBGCC_H */

arch/mips/lib/lshrdi3.c

@@ -0,0 +1,25 @@
+#include "libgcc.h"
+
+long long __lshrdi3(long long u, word_type b)
+{
+	DWunion uu, w;
+	word_type bm;
+
+	if (b == 0)
+		return u;
+
+	uu.ll = u;
+	bm = 32 - b;
+
+	if (bm <= 0) {
+		w.s.high = 0;
+		w.s.low = (unsigned int) uu.s.high >> -bm;
+	} else {
+		const unsigned int carries = (unsigned int) uu.s.high << bm;
+
+		w.s.high = (unsigned int) uu.s.high >> b;
+		w.s.low = ((unsigned int) uu.s.low >> b) | carries;
+	}
+
+	return w.ll;
+}