ARC: Boot #1: low-level, setup_arch(), /proc/cpuinfo, mem init
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
diff --git a/arch/arc/kernel/head.S b/arch/arc/kernel/head.S
new file mode 100644
index 0000000..e63f6a4
--- /dev/null
+++ b/arch/arc/kernel/head.S
@@ -0,0 +1,78 @@
+/*
+ * ARC CPU startup Code
+ *
+ * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * Vineetg: Dec 2007
+ * -Check if we are running on Simulator or on real hardware
+ * to skip certain things during boot on simulator
+ */
+
+#include <asm/asm-offsets.h>
+#include <asm/entry.h>
+#include <linux/linkage.h>
+#include <asm/arcregs.h>
+
+ .cpu A7
+
+ .section .init.text, "ax",@progbits
+ .type stext, @function
+ .globl stext
+stext:
+ ;-------------------------------------------------------------------
+ ; Don't clobber r0-r4 yet. It might have bootloader provided info
+ ;-------------------------------------------------------------------
+
+ ; Clear BSS before updating any globals
+ ; XXX: use ZOL here
+ mov r5, __bss_start
+ mov r6, __bss_stop
+1:
+ st.ab 0, [r5,4]
+ brlt r5, r6, 1b
+
+#ifdef CONFIG_CMDLINE_UBOOT
+ ; support for bootloader provided cmdline
+ ; If cmdline passed by u-boot, then
+ ; r0 = 1 (because ATAGS parsing, now retired, used to use 0)
+ ; r1 = magic number (board identity)
+ ; r2 = addr of cmdline string (somewhere in memory/flash)
+
+ brne r0, 1, .Lother_bootup_chores ; u-boot didn't pass cmdline
+ breq r2, 0, .Lother_bootup_chores ; or cmdline is NULL
+
+ mov r5, @command_line
+1:
+ ldb.ab r6, [r2, 1]
+ breq r6, 0, .Lother_bootup_chores
+ b.d 1b
+ stb.ab r6, [r5, 1]
+#endif
+
+.Lother_bootup_chores:
+
+ ; Identify if running on ISS vs Silicon
+ ; IDENTITY Reg [ 3 2 1 0 ]
+ ; (chip-id) ^^^^^ ==> 0xffff for ISS
+ lr r0, [identity]
+ lsr r3, r0, 16
+ cmp r3, 0xffff
+ mov.z r4, 0
+ mov.nz r4, 1
+ st r4, [@running_on_hw]
+
+ ; setup "current" tsk and optionally cache it in dedicated r25
+ mov r9, @init_task
+ SET_CURR_TASK_ON_CPU r9, r0 ; r9 = tsk, r0 = scratch
+
+ ; setup stack (fp, sp)
+ mov fp, 0
+
+ ; tsk->thread_info is really a PAGE, whose bottom hoists stack
+ GET_TSK_STACK_BASE r9, sp ; r9 = tsk, sp = stack base(output)
+
+ j start_kernel ; "C" entry point