coreboot-kgpe-d16/payloads/libpayload/arch/mips/head.S
Ionela Voinescu ce22c02387 libpayload: arch/mips: Add basic MIPS architecture support
Add the basic build infrastructure and architectural support
required to build for targets using the MIPS architecture.
This will require the addition of cache maintenance.

BUG=chrome-os-partner:31438
TEST=tested on Pistachio FPGA with Depthcharge as payload;
     successfully executed payload.
BRANCH=none

Change-Id: I75cfd0536860b6d84b53a567940fe6668d9b2cbb
Signed-off-by: Patrick Georgi <pgeorgi@chromium.org>
Original-Commit-Id: 758c8cb9a6846e6ca32be409ec5f7a888ac9c888
Original-Signed-off-by: Ionela Voinescu <ionela.voinescu@imgtec.com>
Original-Change-Id: I0b9af983bf5032335a519ce2510a0b3aca082edf
Original-Reviewed-on: https://chromium-review.googlesource.com/219740
Original-Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: http://review.coreboot.org/8741
Tested-by: build bot (Jenkins)
Reviewed-by: Patrick Georgi <pgeorgi@google.com>
2015-03-21 11:07:50 +01:00

110 lines
2.2 KiB
ArmAsm

/*
* This file is part of the libpayload project.
*
* Copyright (C) 2014 Imagination Technologies
*
* 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; version 2 of the License.
*
* 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., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include <arch/cpu.h>
/* Disable interrupts and mark the kernel mode */
.macro setup_c0_status clr
.set push
mfc0 $t0, $CP0_STATUS
or $t0, ST0_CU0 | 0x1f | \clr
xor $t0, 0x1f | \clr
mtc0 $t0, $CP0_STATUS
.set noreorder
sll $zero, 3
.set pop
.endm
/* Don't reorder instructions */
.set noreorder
.align 4
.global cb_header_ptr
cb_header_ptr:
.word 0
.global old_sp
old_sp:
.word 0
.global _entry, _leave
.text
/* Our entry point */
_entry:
/*
* This function saves off the previous stack and switches us to our
* own execution environment.
*/
/* Clear watch and cause registers */
mtc0 $zero, $CP0_WATCHLO
mtc0 $zero, $CP0_WATCHHI
mtc0 $zero, $CP0_CAUSE
/* Disable interrupts */
setup_c0_status 0
/* Don't use at in synthetic instr. */
.set noat
/* Init timer */
mtc0 $zero, $CP0_COUNT
mtc0 $zero, $CP0_COMPARE
/* Initialize $gp */
bal 1f
nop
.word _gp
1:
lw $gp, 0($ra)
/* Clear .bss: start_bss = _edata, end_bss = _end */
la $t0, _edata
sw $zero, ($t0)
la $t1, _end - 4
clear_bss:
addiu $t0, 4
sw $zero, ($t0)
bne $t0, $t1, clear_bss
nop
/* Save off the location of the coreboot tables */
la $at, cb_header_ptr
sw $a0, 0x00($at)
/* Save old stack pointer */
la $at, old_sp
sw $sp, 0x00($at)
/* Setup new stack */
la $sp, _stack
/* Let's rock */
la $a2, start_main
jalr $a2
nop
_leave:
/* Restore old stack. */
lw $sp, old_sp
/* Return to the original context. */
eret