u-boot/arch/mips/cpu/mips64/start.S
Gabor Juhos 67d80c9f97 MIPS: start.S: don't save flush_cache parameters in advance
Saving the parameters in advance unnecessarily complicates
the code. The destination address is already saved in the
's2' register, and that register is not clobbered by the
copy loop. The size of the copied data can be computed
after the copy loop is done.

Change the code to compute the size parameter right
before calling flush_cache, and set the destination
address parameter in the delay slot of the actuall
call.

Signed-off-by: Gabor Juhos <juhosg@openwrt.org>
Cc: Daniel Schwierzeck <daniel.schwierzeck@googlemail.com>
2013-01-27 16:40:15 +01:00

248 lines
4.9 KiB
ArmAsm

/*
* Startup Code for MIPS64 CPU-core
*
* Copyright (c) 2003 Wolfgang Denk <wd@denx.de>
*
* See file CREDITS for list of people who contributed to this
* project.
*
* 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; either version 2 of
* the License, or (at your option) any dlater version.
*
* 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 PARTICUdlaR 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., 59 Temple Pdlace, Suite 330, Boston,
* MA 02111-1307 USA
*/
#include <asm-offsets.h>
#include <config.h>
#include <asm/regdef.h>
#include <asm/mipsregs.h>
#ifndef CONFIG_SYS_MIPS_CACHE_MODE
#define CONFIG_SYS_MIPS_CACHE_MODE CONF_CM_CACHABLE_NONCOHERENT
#endif
/*
* For the moment disable interrupts, mark the kernel mode and
* set ST0_KX so that the CPU does not spit fire when using
* 64-bit addresses.
*/
.macro setup_c0_status set clr
.set push
mfc0 t0, CP0_STATUS
or t0, ST0_CU0 | \set | 0x1f | \clr
xor t0, 0x1f | \clr
mtc0 t0, CP0_STATUS
.set noreorder
sll zero, 3 # ehb
.set pop
.endm
.set noreorder
.globl _start
.text
_start:
.org 0x000
b reset
nop
.org 0x080
b romReserved
nop
.org 0x100
b romReserved
nop
.org 0x180
b romReserved
nop
.org 0x200
b romReserved
nop
.org 0x280
b romReserved
nop
.org 0x300
b romReserved
nop
.org 0x380
b romReserved
nop
.org 0x480
b romReserved
nop
/*
* We hope there are no more reserved vectors!
* 128 * 8 == 1024 == 0x400
* so this is address R_VEC+0x400 == 0xbfc00400
*/
.org 0x500
.align 4
reset:
/* Clear watch registers */
dmtc0 zero, CP0_WATCHLO
dmtc0 zero, CP0_WATCHHI
/* WP(Watch Pending), SW0/1 should be cleared */
mtc0 zero, CP0_CAUSE
setup_c0_status ST0_KX 0
/* Init Timer */
mtc0 zero, CP0_COUNT
mtc0 zero, CP0_COMPARE
#ifndef CONFIG_SKIP_LOWLEVEL_INIT
/* CONFIG0 register */
dli t0, CONF_CM_UNCACHED
mtc0 t0, CP0_CONFIG
#endif
/*
* Initialize $gp, force 8 byte alignment of bal instruction to forbid
* the compiler to put nop's between bal and _gp. This is required to
* keep _gp and ra aligned to 8 byte.
*/
.align 3
bal 1f
nop
.dword _gp
1:
ld gp, 0(ra)
#ifndef CONFIG_SKIP_LOWLEVEL_INIT
/* Initialize any external memory */
dla t9, lowlevel_init
jalr t9
nop
/* Initialize caches... */
dla t9, mips_cache_reset
jalr t9
nop
/* ... and enable them */
dli t0, CONFIG_SYS_MIPS_CACHE_MODE
mtc0 t0, CP0_CONFIG
#endif
/* Set up temporary stack */
dli sp, CONFIG_SYS_SDRAM_BASE + CONFIG_SYS_INIT_SP_OFFSET
dla t9, board_init_f
jr t9
nop
/*
* void relocate_code (addr_sp, gd, addr_moni)
*
* This "function" does not return, instead it continues in RAM
* after relocating the monitor code.
*
* a0 = addr_sp
* a1 = gd
* a2 = destination address
*/
.globl relocate_code
.ent relocate_code
relocate_code:
move sp, a0 # set new stack pointer
move s0, a1 # save gd in s0
move s2, a2 # save destination address in s2
dli t0, CONFIG_SYS_MONITOR_BASE
dsub s1, s2, t0 # s1 <-- relocation offset
dla t3, in_ram
ld t2, -24(t3) # t2 <-- uboot_end_data
move t1, a2
dadd gp, s1 # adjust gp
/*
* t0 = source address
* t1 = target address
* t2 = source end address
*/
1:
lw t3, 0(t0)
sw t3, 0(t1)
daddu t0, 4
blt t0, t2, 1b
daddu t1, 4
/* If caches were enabled, we would have to flush them here. */
dsub a1, t1, s2 # a1 <-- size
dla t9, flush_cache
jalr t9
move a0, s2 # a0 <-- destination address
/* Jump to where we've relocated ourselves */
daddi t0, s2, in_ram - _start
jr t0
nop
.dword _gp
.dword _GLOBAL_OFFSET_TABLE_
.dword uboot_end_data
.dword uboot_end
.dword num_got_entries
in_ram:
/*
* Now we want to update GOT.
*
* GOT[0] is reserved. GOT[1] is also reserved for the dynamic object
* generated by GNU ld. Skip these reserved entries from relocation.
*/
ld t3, -8(t0) # t3 <-- num_got_entries
ld t8, -32(t0) # t8 <-- _GLOBAL_OFFSET_TABLE_
ld t9, -40(t0) # t9 <-- _gp
dsub t8, t9 # compute offset
dadd t8, t8, gp # t8 now holds relocated _G_O_T_
daddi t8, t8, 16 # skipping first two entries
dli t2, 2
1:
ld t1, 0(t8)
beqz t1, 2f
dadd t1, s1
sd t1, 0(t8)
2:
daddi t2, 1
blt t2, t3, 1b
daddi t8, 8
/* Clear BSS */
ld t1, -24(t0) # t1 <-- uboot_end_data
ld t2, -16(t0) # t2 <-- uboot_end
dadd t1, s1 # adjust pointers
dadd t2, s1
dsub t1, 8
1:
daddi t1, 8
bltl t1, t2, 1b
sd zero, 0(t1)
move a0, s0 # a0 <-- gd
dla t9, board_init_r
jr t9
move a1, s2
.end relocate_code
/* Exception handlers */
romReserved:
b romReserved
nop