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freebsd-skq/stand/powerpc/uboot/start.S

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MFp4 (e500): Add support for U-Boot. This uses the U-Boot API as developed by Rafal and which is (will be) part of U-Boot 1.3.2 and later. Credits to: raj@
2008-02-16 22:40:55 +00:00
/*-
* Copyright (c) 2007 Semihalf, Rafal Jaworowski <raj@semihalf.com>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
Move the $FreeBSD$ tag in a comment as __FBSDID doesn't work.
2008-02-17 20:38:22 +00:00
*
* $FreeBSD$
MFp4 (e500): Add support for U-Boot. This uses the U-Boot API as developed by Rafal and which is (will be) part of U-Boot 1.3.2 and later. Credits to: raj@
2008-02-16 22:40:55 +00:00
*/
#include <machine/asm.h>
/*
* Entry point to the loader that U-Boot passes control to.
*/
o Keep running on U-Boot's stack. o Disable interrupts while not running U-Boot code. We clobber registers that the U-Boot interrupt handlers assume to be fixed as per the U-Boot register usage. At this time this only applies to r14. U-Boot uses r2 now for what they used r29 for. After we restore r14 in preparation of doing the syscall, we re-enable interrupts. When we return from the syscall, we disable interrupts and restore the callee-saved r14.
2008-02-23 18:42:53 +00:00
.text
.globl _start
MFp4 (e500): Add support for U-Boot. This uses the U-Boot API as developed by Rafal and which is (will be) part of U-Boot 1.3.2 and later. Credits to: raj@
2008-02-16 22:40:55 +00:00
_start:
o Keep running on U-Boot's stack. o Disable interrupts while not running U-Boot code. We clobber registers that the U-Boot interrupt handlers assume to be fixed as per the U-Boot register usage. At this time this only applies to r14. U-Boot uses r2 now for what they used r29 for. After we restore r14 in preparation of doing the syscall, we re-enable interrupts. When we return from the syscall, we disable interrupts and restore the callee-saved r14.
2008-02-23 18:42:53 +00:00
/* Hint where to look for the API signature */
lis %r11, uboot_address@ha
addi %r11, %r11, uboot_address@l
Use current SP instead of global data ptr for the U-Boot API signature search hint. Global data (pointed by R2 on PowerPC) in principle is not guaranteed to be in proximity of U-Boot heap (where the API signature is placed) accross different architectures and platforms. Instead, use U-Boot stack pointer as a hint for the search instead of the global data; this method tends to be more uniform accross different platforms. Obtained from: Semihalf
2008-09-03 16:38:27 +00:00
stw %r1, 0(%r11)
o Keep running on U-Boot's stack. o Disable interrupts while not running U-Boot code. We clobber registers that the U-Boot interrupt handlers assume to be fixed as per the U-Boot register usage. At this time this only applies to r14. U-Boot uses r2 now for what they used r29 for. After we restore r14 in preparation of doing the syscall, we re-enable interrupts. When we return from the syscall, we disable interrupts and restore the callee-saved r14.
2008-02-23 18:42:53 +00:00
/* Save U-Boot's r14 */
MFp4 (e500): Add support for U-Boot. This uses the U-Boot API as developed by Rafal and which is (will be) part of U-Boot 1.3.2 and later. Credits to: raj@
2008-02-16 22:40:55 +00:00
lis %r11, saved_regs@ha
addi %r11, %r11, saved_regs@l
stw %r14, 0(%r11)
o Keep running on U-Boot's stack. o Disable interrupts while not running U-Boot code. We clobber registers that the U-Boot interrupt handlers assume to be fixed as per the U-Boot register usage. At this time this only applies to r14. U-Boot uses r2 now for what they used r29 for. After we restore r14 in preparation of doing the syscall, we re-enable interrupts. When we return from the syscall, we disable interrupts and restore the callee-saved r14.
2008-02-23 18:42:53 +00:00
/* Disable interrupts */
mfmsr %r11
andi. %r11, %r11, ~0x8000@l
mtmsr %r11
MFp4 (e500): Add support for U-Boot. This uses the U-Boot API as developed by Rafal and which is (will be) part of U-Boot 1.3.2 and later. Credits to: raj@
2008-02-16 22:40:55 +00:00
b main
/*
* syscall()
*/
ENTRY(syscall)
stwu %r1, -16(%r1)
mflr %r0
stw %r14, 8(%r1)
stw %r0, 20(%r1)
o Keep running on U-Boot's stack. o Disable interrupts while not running U-Boot code. We clobber registers that the U-Boot interrupt handlers assume to be fixed as per the U-Boot register usage. At this time this only applies to r14. U-Boot uses r2 now for what they used r29 for. After we restore r14 in preparation of doing the syscall, we re-enable interrupts. When we return from the syscall, we disable interrupts and restore the callee-saved r14.
2008-02-23 18:42:53 +00:00
/* Restore U-Boot's r14 */
MFp4 (e500): Add support for U-Boot. This uses the U-Boot API as developed by Rafal and which is (will be) part of U-Boot 1.3.2 and later. Credits to: raj@
2008-02-16 22:40:55 +00:00
lis %r11, saved_regs@ha
addi %r11, %r11, saved_regs@l
lwz %r14, 0(%r11)
o Keep running on U-Boot's stack. o Disable interrupts while not running U-Boot code. We clobber registers that the U-Boot interrupt handlers assume to be fixed as per the U-Boot register usage. At this time this only applies to r14. U-Boot uses r2 now for what they used r29 for. After we restore r14 in preparation of doing the syscall, we re-enable interrupts. When we return from the syscall, we disable interrupts and restore the callee-saved r14.
2008-02-23 18:42:53 +00:00
/* Enable interrupts */
mfmsr %r11
ori %r11, %r11, 0x8000@l
mtmsr %r11
/* Call into U-Boot */
MFp4 (e500): Add support for U-Boot. This uses the U-Boot API as developed by Rafal and which is (will be) part of U-Boot 1.3.2 and later. Credits to: raj@
2008-02-16 22:40:55 +00:00
lis %r11, syscall_ptr@ha
addi %r11, %r11, syscall_ptr@l
lwz %r11, 0(%r11)
mtctr %r11
bctrl
o Keep running on U-Boot's stack. o Disable interrupts while not running U-Boot code. We clobber registers that the U-Boot interrupt handlers assume to be fixed as per the U-Boot register usage. At this time this only applies to r14. U-Boot uses r2 now for what they used r29 for. After we restore r14 in preparation of doing the syscall, we re-enable interrupts. When we return from the syscall, we disable interrupts and restore the callee-saved r14.
2008-02-23 18:42:53 +00:00
/* Disable interrupts */
mfmsr %r11
andi. %r11, %r11, ~0x8000@l
mtmsr %r11
MFp4 (e500): Add support for U-Boot. This uses the U-Boot API as developed by Rafal and which is (will be) part of U-Boot 1.3.2 and later. Credits to: raj@
2008-02-16 22:40:55 +00:00
/* Epilogue */
lwz %r11, 0(%r1)
lwz %r0, 4(%r11)
mtlr %r0
lwz %r14, 8(%r1)
mr %r1, %r11
blr
/*
* Data section
*/
.data
GLOBAL(syscall_ptr)
.long 0
GLOBAL(saved_regs)
.long 0 /* R14 */
o Keep running on U-Boot's stack. o Disable interrupts while not running U-Boot code. We clobber registers that the U-Boot interrupt handlers assume to be fixed as per the U-Boot register usage. At this time this only applies to r14. U-Boot uses r2 now for what they used r29 for. After we restore r14 in preparation of doing the syscall, we re-enable interrupts. When we return from the syscall, we disable interrupts and restore the callee-saved r14.
2008-02-23 18:42:53 +00:00
GLOBAL(uboot_address)
.long 0
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