ARM: Add macros.h to be used in assembler file.

Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>

include/asm-arm/macro.h

+/*
+ * include/asm-arm/macro.h
+ *
+ * Copyright (C) 2009 Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
+ *
+ * See file CREDITS for list of people who contributed to this
+ * project.
+ *
+ * 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 program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
+ * MA 02111-1307 USA
+ */
+
+#ifndef __ASM_ARM_MACRO_H__
+#define __ASM_ARM_MACRO_H__
+#ifdef __ASSEMBLY__
+
+/*
+ * These macros provide a convenient way to write 8, 16 and 32 bit data
+ * to any address.
+ * Registers r4 and r5 are used, any data in these registers are
+ * overwritten by the macros.
+ * The macros are valid for any ARM architecture, they do not implement
+ * any memory barriers so caution is recommended when using these when the
+ * caches are enabled or on a multi-core system.
+ */
+
+.macro	write32, addr, data
+	ldr	r4, =\addr
+	ldr	r5, =\data
+	str	r5, [r4]
+.endm
+
+.macro	write16, addr, data
+	ldr	r4, =\addr
+	ldrh	r5, =\data
+	strh	r5, [r4]
+.endm
+
+.macro	write8, addr, data
+	ldr	r4, =\addr
+	ldrb	r5, =\data
+	strb	r5, [r4]
+.endm
+
+/*
+ * This macro generates a loop that can be used for delays in the code.
+ * Register r4 is used, any data in this register is overwritten by the
+ * macro.
+ * The macro is valid for any ARM architeture. The actual time spent in the
+ * loop will vary from CPU to CPU though.
+ */
+
+.macro	wait_timer, time
+	ldr	r4, =\time
+1:
+	nop
+	subs	r4, r4, #1
+	bcs	1b
+.endm
+
+#endif /* __ASSEMBLY__ */
+#endif /* __ASM_ARM_MACRO_H__ */