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-rw-r--r--arch/nios2/boot/compressed/head.S117
1 files changed, 117 insertions, 0 deletions
diff --git a/arch/nios2/boot/compressed/head.S b/arch/nios2/boot/compressed/head.S
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+/*
+ * Copyright (C) 2009 Thomas Chou <thomas@wytron.com.tw>
+ *
+ * Based on arch/nios2/kernel/head.S
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License. See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ */
+
+/*
+ * This code can be loaded anywhere, eg FLASH ROM as reset vector,
+ * as long as output does not overlap it.
+ */
+
+#include <linux/linkage.h>
+#include <asm/cache.h>
+
+ .text
+ .set noat
+ENTRY(_start)
+ wrctl status, r0 /* disable interrupt */
+ /* invalidate all instruction cache */
+ movia r1, NIOS2_ICACHE_SIZE
+ movui r2, NIOS2_ICACHE_LINE_SIZE
+1: initi r1
+ sub r1, r1, r2
+ bgt r1, r0, 1b
+ /* invalidate all data cache */
+ movia r1, NIOS2_DCACHE_SIZE
+ movui r2, NIOS2_DCACHE_LINE_SIZE
+1: initd 0(r1)
+ sub r1, r1, r2
+ bgt r1, r0, 1b
+
+ nextpc r1 /* Find out where we are */
+chkadr:
+ movia r2, chkadr
+ beq r1, r2, finish_move /* We are running in correct address,
+ done */
+ /* move code, r1: src, r2: dest, r3: last dest */
+ addi r1, r1, (_start - chkadr) /* Source */
+ movia r2, _start /* Destination */
+ movia r3, __bss_start /* End of copy */
+1: ldw r8, 0(r1) /* load a word from [r1] */
+ stw r8, 0(r2) /* stort a word to dest [r2] */
+ addi r1, r1, 4 /* inc the src addr */
+ addi r2, r2, 4 /* inc the dest addr */
+ blt r2, r3, 1b
+ /* flush the data cache after moving */
+ movia r1, NIOS2_DCACHE_SIZE
+ movui r2, NIOS2_DCACHE_LINE_SIZE
+1: flushd 0(r1)
+ sub r1, r1, r2
+ bgt r1, r0, 1b
+ movia r1, finish_move
+ jmp r1 /* jmp to linked address */
+
+finish_move:
+ /* zero out the .bss segment (uninitialized common data) */
+ movia r2, __bss_start /* presume nothing is between */
+ movia r1, _end /* the .bss and _end. */
+1: stb r0, 0(r2)
+ addi r2, r2, 1
+ bne r1, r2, 1b
+ /*
+ * set up the stack pointer, some where higher than _end.
+ * The stack space must be greater than 32K for decompress.
+ */
+ movia sp, 0x10000
+ add sp, sp, r1
+ /* save args passed from u-boot, maybe */
+ addi sp, sp, -16
+ stw r4, 0(sp)
+ stw r5, 4(sp)
+ stw r6, 8(sp)
+ stw r7, 12(sp)
+ /* decompress the kernel */
+ call decompress_kernel
+ /* pass saved args to kernel */
+ ldw r4, 0(sp)
+ ldw r5, 4(sp)
+ ldw r6, 8(sp)
+ ldw r7, 12(sp)
+
+ /* flush all data cache after decompressing */
+ movia r1, NIOS2_DCACHE_SIZE
+ movui r2, NIOS2_DCACHE_LINE_SIZE
+1: flushd 0(r1)
+ sub r1, r1, r2
+ bgt r1, r0, 1b
+ /* flush all instruction cache */
+ movia r1, NIOS2_ICACHE_SIZE
+ movui r2, NIOS2_ICACHE_LINE_SIZE
+1: flushi r1
+ sub r1, r1, r2
+ bgt r1, r0, 1b
+ flushp
+ /* jump to start real kernel */
+ movia r1, (CONFIG_NIOS2_MEM_BASE | CONFIG_NIOS2_KERNEL_REGION_BASE)
+ jmp r1
+
+ .balign 512
+fake_headers_as_bzImage:
+ .short 0
+ .ascii "HdrS"
+ .short 0x0202
+ .short 0
+ .short 0
+ .byte 0x00, 0x10
+ .short 0
+ .byte 0
+ .byte 1
+ .byte 0x00, 0x80
+ .long 0
+ .long 0