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u-boot/arch/mips/cpu/start.S
Weijie Gao c95c3ec025 mips: add a option to support not reserving malloc space on initial stack 
The initial stack on some platforms is too small to hold a large malloc
space. This patch adds a option to allow these platforms not reserving the
malloc space on initial stack. These platforms should set the malloc base
after DRAM is usable.

Reviewed-by: Stefan Roese <sr@denx.de>
Signed-off-by: Weijie Gao <weijie.gao@mediatek.com>
2020-04-27 20:29:33 +02:00

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/* SPDX-License-Identifier: GPL-2.0+ */
/*
* Startup Code for MIPS32 CPU-core
*
* Copyright (c) 2003 Wolfgang Denk <wd@denx.de>
*/
#include <asm-offsets.h>
#include <config.h>
#include <asm/asm.h>
#include <asm/regdef.h>
#include <asm/mipsregs.h>
#ifndef CONFIG_SYS_INIT_SP_ADDR
#define CONFIG_SYS_INIT_SP_ADDR (CONFIG_SYS_SDRAM_BASE + \
CONFIG_SYS_INIT_SP_OFFSET)
#endif
#ifdef CONFIG_32BIT
# define MIPS_RELOC 3
# define STATUS_SET 0
#endif
#ifdef CONFIG_64BIT
# ifdef CONFIG_SYS_LITTLE_ENDIAN
# define MIPS64_R_INFO(ssym, r_type3, r_type2, r_type) \
(((r_type) << 24) | ((r_type2) << 16) | ((r_type3) << 8) | (ssym))
# else
# define MIPS64_R_INFO(ssym, r_type3, r_type2, r_type) \
((r_type) | ((r_type2) << 8) | ((r_type3) << 16) | (ssym) << 24)
# endif
# define MIPS_RELOC MIPS64_R_INFO(0x00, 0x00, 0x12, 0x03)
# define STATUS_SET ST0_KX
#endif
.set noreorder
.macro init_wr sel
MTC0 zero, CP0_WATCHLO,\sel
mtc0 t1, CP0_WATCHHI,\sel
mfc0 t0, CP0_WATCHHI,\sel
bgez t0, wr_done
nop
.endm
.macro uhi_mips_exception
move k0, t9 # preserve t9 in k0
move k1, a0 # preserve a0 in k1
li t9, 15 # UHI exception operation
li a0, 0 # Use hard register context
sdbbp 1 # Invoke UHI operation
.endm
.macro setup_stack_gd
li t0, -16
PTR_LI t1, CONFIG_SYS_INIT_SP_ADDR
and sp, t1, t0 # force 16 byte alignment
PTR_SUBU \
sp, sp, GD_SIZE # reserve space for gd
and sp, sp, t0 # force 16 byte alignment
move k0, sp # save gd pointer
#if CONFIG_VAL(SYS_MALLOC_F_LEN) && \
!CONFIG_IS_ENABLED(INIT_STACK_WITHOUT_MALLOC_F)
li t2, CONFIG_VAL(SYS_MALLOC_F_LEN)
PTR_SUBU \
sp, sp, t2 # reserve space for early malloc
and sp, sp, t0 # force 16 byte alignment
#endif
move fp, sp
/* Clear gd */
move t0, k0
1:
PTR_S zero, 0(t0)
PTR_ADDIU t0, PTRSIZE
blt t0, t1, 1b
nop
#if CONFIG_VAL(SYS_MALLOC_F_LEN) && \
!CONFIG_IS_ENABLED(INIT_STACK_WITHOUT_MALLOC_F)
PTR_S sp, GD_MALLOC_BASE(k0) # gd->malloc_base offset
#endif
.endm
ENTRY(_start)
/* U-Boot entry point */
b reset
mtc0 zero, CP0_COUNT # clear cp0 count for most accurate boot timing
#if defined(CONFIG_MIPS_INSERT_BOOT_CONFIG)
/*
* Store some board-specific boot configuration. This is used by some
* MIPS systems like Malta.
*/
.org 0x10
.word CONFIG_MIPS_BOOT_CONFIG_WORD0
.word CONFIG_MIPS_BOOT_CONFIG_WORD1
#endif
#if defined(CONFIG_ROM_EXCEPTION_VECTORS)
/*
* Exception vector entry points. When running from ROM, an exception
* cannot be handled. Halt execution and transfer control to debugger,
* if one is attached.
*/
.org 0x200
/* TLB refill, 32 bit task */
uhi_mips_exception
.org 0x280
/* XTLB refill, 64 bit task */
uhi_mips_exception
.org 0x300
/* Cache error exception */
uhi_mips_exception
.org 0x380
/* General exception */
uhi_mips_exception
.org 0x400
/* Catch interrupt exceptions */
uhi_mips_exception
.org 0x480
/* EJTAG debug exception */
1: b 1b
nop
.org 0x500
#endif
reset:
#if __mips_isa_rev >= 6
mfc0 t0, CP0_CONFIG, 5
and t0, t0, MIPS_CONF5_VP
beqz t0, 1f
nop
b 2f
mfc0 t0, CP0_GLOBALNUMBER
#endif
#ifdef CONFIG_ARCH_BMIPS
1: mfc0 t0, CP0_DIAGNOSTIC, 3
and t0, t0, (1 << 31)
#else
1: mfc0 t0, CP0_EBASE
and t0, t0, EBASE_CPUNUM
#endif
/* Hang if this isn't the first CPU in the system */
2: beqz t0, 4f
nop
3: wait
b 3b
nop
/* Init CP0 Status */
4: mfc0 t0, CP0_STATUS
and t0, ST0_IMPL
or t0, ST0_BEV | ST0_ERL | STATUS_SET
mtc0 t0, CP0_STATUS
/*
* Check whether CP0 Config1 is implemented. If not continue
* with legacy Watch register initialization.
*/
mfc0 t0, CP0_CONFIG
bgez t0, wr_legacy
nop
/*
* Check WR bit in CP0 Config1 to determine if Watch registers
* are implemented.
*/
mfc0 t0, CP0_CONFIG, 1
andi t0, (1 << 3)
beqz t0, wr_done
nop
/* Clear Watch Status bits and disable watch exceptions */
li t1, 0x7 # Clear I, R and W conditions
init_wr 0
init_wr 1
init_wr 2
init_wr 3
init_wr 4
init_wr 5
init_wr 6
init_wr 7
b wr_done
nop
wr_legacy:
MTC0 zero, CP0_WATCHLO
mtc0 zero, CP0_WATCHHI
wr_done:
/* Clear WP, IV and SW interrupts */
mtc0 zero, CP0_CAUSE
/* Clear timer interrupt (CP0_COUNT cleared on branch to 'reset') */
mtc0 zero, CP0_COMPARE
#ifndef CONFIG_SKIP_LOWLEVEL_INIT
mfc0 t0, CP0_CONFIG
and t0, t0, MIPS_CONF_IMPL
or t0, t0, CONF_CM_UNCACHED
mtc0 t0, CP0_CONFIG
ehb
#endif
#ifdef CONFIG_MIPS_CM
PTR_LA t9, mips_cm_map
jalr t9
nop
#endif
#ifdef CONFIG_MIPS_INIT_STACK_IN_SRAM
#ifdef CONFIG_MIPS_SRAM_INIT
/* Initialize the SRAM first */
PTR_LA t9, mips_sram_init
jalr t9
nop
#endif
/* Set up initial stack and global data */
setup_stack_gd
# ifdef CONFIG_DEBUG_UART
/* Earliest point to set up debug uart */
PTR_LA t9, debug_uart_init
jalr t9
nop
# endif
#endif
#ifndef CONFIG_SKIP_LOWLEVEL_INIT
# ifdef CONFIG_SYS_MIPS_CACHE_INIT_RAM_LOAD
/* Initialize any external memory */
PTR_LA t9, lowlevel_init
jalr t9
nop
# endif
/* Initialize caches... */
PTR_LA t9, mips_cache_reset
jalr t9
nop
# ifndef CONFIG_SYS_MIPS_CACHE_INIT_RAM_LOAD
/* Initialize any external memory */
PTR_LA t9, lowlevel_init
jalr t9
nop
# endif
#endif
#ifndef CONFIG_MIPS_INIT_STACK_IN_SRAM
/* Set up initial stack and global data */
setup_stack_gd
# ifdef CONFIG_DEBUG_UART
/* Earliest point to set up debug uart */
PTR_LA t9, debug_uart_init
jalr t9
nop
# endif
#endif
move a0, zero # a0 <-- boot_flags = 0
PTR_LA t9, board_init_f
jr t9
move ra, zero
END(_start)
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