1/*- 2 * Copyright (c) 2008 Semihalf, Rafal Czubak 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24 * SUCH DAMAGE. 25 * 26 * $FreeBSD$ 27 */ 28 29#include <machine/asm.h> 30 31/* 32 * Entry point to the loader that U-Boot passes control to. 33 */ 34 .text 35 .globl _start 36_start: 37 /* Hint where to look for the API signature */ 38 ldr ip, =uboot_address 39 str sp, [ip] 40 41 /* Save U-Boot's r8 */ 42 ldr ip, =saved_regs 43 str r8, [ip, #0] 44 45 /* Start loader */ 46 b main 47 48/* 49 * syscall() 50 */ 51ENTRY(syscall) 52 /* Save caller's lr */ 53 ldr ip, =saved_regs 54 str lr, [ip, #4] 55 /* Save loader's r8 */ 56 ldr ip, =saved_regs 57 str r8, [ip, #8] 58 59 /* Restore U-Boot's r8 */ 60 ldr ip, =saved_regs 61 ldr r8, [ip, #0] 62 /* Call into U-Boot */ 63 ldr lr, =return_from_syscall 64 ldr ip, =syscall_ptr 65 ldr pc, [ip] 66 67return_from_syscall: 68 /* Restore loader's r8 */ 69 ldr ip, =saved_regs 70 ldr r8, [ip, #8] 71 /* Restore caller's lr */ 72 ldr ip, =saved_regs 73 ldr lr, [ip, #4] 74 /* Return to caller */ 75 mov pc, lr 76 77/* 78 * Data section 79 */ 80 .data 81 .align 4 82 .globl syscall_ptr 83syscall_ptr: 84 .long 0 85 86 .globl uboot_address 87uboot_address: 88 .long 0 89 90saved_regs: 91 .long 0 /* U-Boot's r8 */ 92 .long 0 /* Loader's r8 */ 93 .long 0 /* Loader's lr */ 94