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u-boot/arch/microblaze/cpu/start.S
Albert ARIBAUD ecc306639e Fix board init code to respect the C runtime environment 
board_init_f_mem() alters the C runtime environment's
stack it is actually already using. This is not a valid
behaviour within a C runtime environment.

Split board_init_f_mem into C functions which do not alter
their own stack and always behave properly with respect to
their C runtime environment.

Signed-off-by: Albert ARIBAUD <albert.u.boot@aribaud.net>
Acked-by: Thomas Chou <thomas@wytron.com.tw>
2016-01-13 21:05:17 -05:00

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/*
* (C) Copyright 2007 Michal Simek
* (C) Copyright 2004 Atmark Techno, Inc.
*
* Michal SIMEK <monstr@monstr.eu>
* Yasushi SHOJI <yashi@atmark-techno.com>
*
* SPDX-License-Identifier: GPL-2.0+
*/
#include <asm-offsets.h>
#include <config.h>
.text
.global _start
_start:
/*
* reserve registers:
* r10: Stores little/big endian offset for vectors
* r2: Stores imm opcode
* r3: Stores brai opcode
*/
mts rmsr, r0 /* disable cache */
addi r8, r0, __end
mts rslr, r8
/* TODO: Redo this code to call board_init_f_*() */
#if defined(CONFIG_SPL_BUILD)
addi r1, r0, CONFIG_SPL_STACK_ADDR
mts rshr, r1
addi r1, r1, -4 /* Decrement SP to top of memory */
#else
#if defined(CONFIG_SYS_MALLOC_F_LEN)
addi r1, r0, CONFIG_SYS_INIT_SP_OFFSET - CONFIG_SYS_MALLOC_F_LEN
#else
addi r1, r0, CONFIG_SYS_INIT_SP_OFFSET
#endif
mts rshr, r1
addi r1, r1, -4 /* Decrement SP to top of memory */
/* Find-out if u-boot is running on BIG/LITTLE endian platform
* There are some steps which is necessary to keep in mind:
* 1. Setup offset value to r6
* 2. Store word offset value to address 0x0
* 3. Load just byte from address 0x0
* 4a) LITTLE endian - r10 contains 0x2 because it is the smallest
* value that's why is on address 0x0
* 4b) BIG endian - r10 contains 0x0 because 0x2 offset is on addr 0x3
*/
addik r6, r0, 0x2 /* BIG/LITTLE endian offset */
lwi r7, r0, 0x28
swi r6, r0, 0x28 /* used first unused MB vector */
lbui r10, r0, 0x28 /* used first unused MB vector */
swi r7, r0, 0x28
/* add opcode instruction for 32bit jump - 2 instruction imm & brai */
addi r2, r0, 0xb0000000 /* hex b000 opcode imm */
addi r3, r0, 0xb8080000 /* hew b808 opcode brai */
#ifdef CONFIG_SYS_RESET_ADDRESS
/* reset address */
swi r2, r0, 0x0 /* reset address - imm opcode */
swi r3, r0, 0x4 /* reset address - brai opcode */
addik r6, r0, CONFIG_SYS_RESET_ADDRESS
sw r6, r1, r0
lhu r7, r1, r10
rsubi r8, r10, 0x2
sh r7, r0, r8
rsubi r8, r10, 0x6
sh r6, r0, r8
#endif
#ifdef CONFIG_SYS_USR_EXCEP
/* user_vector_exception */
swi r2, r0, 0x8 /* user vector exception - imm opcode */
swi r3, r0, 0xC /* user vector exception - brai opcode */
addik r6, r0, _exception_handler
sw r6, r1, r0
/*
* BIG ENDIAN memory map for user exception
* 0x8: 0xB000XXXX
* 0xC: 0xB808XXXX
*
* then it is necessary to count address for storing the most significant
* 16bits from _exception_handler address and copy it to
* 0xa address. Big endian use offset in r10=0 that's why is it just
* 0xa address. The same is done for the least significant 16 bits
* for 0xe address.
*
* LITTLE ENDIAN memory map for user exception
* 0x8: 0xXXXX00B0
* 0xC: 0xXXXX08B8
*
* Offset is for little endian setup to 0x2. rsubi instruction decrease
* address value to ensure that points to proper place which is
* 0x8 for the most significant 16 bits and
* 0xC for the least significant 16 bits
*/
lhu r7, r1, r10
rsubi r8, r10, 0xa
sh r7, r0, r8
rsubi r8, r10, 0xe
sh r6, r0, r8
#endif
/* interrupt_handler */
swi r2, r0, 0x10 /* interrupt - imm opcode */
swi r3, r0, 0x14 /* interrupt - brai opcode */
addik r6, r0, _interrupt_handler
sw r6, r1, r0
lhu r7, r1, r10
rsubi r8, r10, 0x12
sh r7, r0, r8
rsubi r8, r10, 0x16
sh r6, r0, r8
/* hardware exception */
swi r2, r0, 0x20 /* hardware exception - imm opcode */
swi r3, r0, 0x24 /* hardware exception - brai opcode */
addik r6, r0, _hw_exception_handler
sw r6, r1, r0
lhu r7, r1, r10
rsubi r8, r10, 0x22
sh r7, r0, r8
rsubi r8, r10, 0x26
sh r6, r0, r8
#endif /* BUILD_SPL */
/* Flush cache before enable cache */
addik r5, r0, 0
addik r6, r0, XILINX_DCACHE_BYTE_SIZE
bralid r15, flush_cache
nop
/* enable instruction and data cache */
mfs r12, rmsr
ori r12, r12, 0x1a0
mts rmsr, r12
/* TODO: Redo this code to call board_init_f_*() */
clear_bss:
/* clear BSS segments */
addi r5, r0, __bss_start
addi r4, r0, __bss_end
cmp r6, r5, r4
beqi r6, 3f
2:
swi r0, r5, 0 /* write zero to loc */
addi r5, r5, 4 /* increment to next loc */
cmp r6, r5, r4 /* check if we have reach the end */
bnei r6, 2b
3: /* jumping to board_init */
#ifndef CONFIG_SPL_BUILD
or r5, r0, r0 /* flags - empty */
addi r31, r0, _gd
#if defined(CONFIG_SYS_MALLOC_F_LEN)
addi r6, r0, CONFIG_SYS_INIT_SP_OFFSET
swi r6, r31, GD_MALLOC_BASE
#endif
brai board_init_f
#else
addi r31, r0, _gd
#if defined(CONFIG_SYS_MALLOC_F_LEN)
addi r6, r0, CONFIG_SPL_STACK_ADDR
swi r6, r31, GD_MALLOC_BASE
#endif
brai board_init_r
#endif
1: bri 1b
.section .bss
.align 4
_gd:
.space GENERATED_GBL_DATA_SIZE
#ifndef CONFIG_SPL_BUILD
/*
* Read 16bit little endian
*/
.text
.global in16
.ent in16
.align 2
in16: lhu r3, r0, r5
bslli r4, r3, 8
bsrli r3, r3, 8
andi r4, r4, 0xffff
or r3, r3, r4
rtsd r15, 8
sext16 r3, r3
.end in16
/*
* Write 16bit little endian
* first parameter(r5) - address, second(r6) - short value
*/
.text
.global out16
.ent out16
.align 2
out16: bslli r3, r6, 8
bsrli r6, r6, 8
andi r3, r3, 0xffff
or r3, r3, r6
sh r3, r0, r5
rtsd r15, 8
or r0, r0, r0
.end out16
/*
* Relocate u-boot
*/
.text
.global relocate_code
.ent relocate_code
.align 2
relocate_code:
/*
* r5 - start_addr_sp
* r6 - new_gd
* r7 - reloc_addr
*/
addi r1, r5, 0 /* Start to use new SP */
addi r31, r6, 0 /* Start to use new GD */
add r23, r0, r7 /* Move reloc addr to r23 */
/* Relocate text and data - r12 temp value */
addi r21, r0, _start
addi r22, r0, __end - 4 /* Include BSS too */
rsub r6, r21, r22
or r5, r0, r0
1: lw r12, r21, r5 /* Load u-boot data */
sw r12, r23, r5 /* Write zero to loc */
cmp r12, r5, r6 /* Check if we have reach the end */
bneid r12, 1b
addi r5, r5, 4 /* Increment to next loc - relocate code */
/* R23 points to the base address. */
add r23, r0, r7 /* Move reloc addr to r23 */
addi r24, r0, CONFIG_SYS_TEXT_BASE /* Get reloc offset */
rsub r23, r24, r23 /* keep - this is already here gd->reloc_off */
addik r6, r0, 0x2 /* BIG/LITTLE endian offset */
lwi r7, r0, 0x28
swi r6, r0, 0x28 /* used first unused MB vector */
lbui r10, r0, 0x28 /* used first unused MB vector */
swi r7, r0, 0x28
#ifdef CONFIG_SYS_USR_EXCEP
addik r6, r0, _exception_handler
addk r6, r6, r23 /* add offset */
sw r6, r1, r0
lhu r7, r1, r10
rsubi r8, r10, 0xa
sh r7, r0, r8
rsubi r8, r10, 0xe
sh r6, r0, r8
#endif
addik r6, r0, _hw_exception_handler
addk r6, r6, r23 /* add offset */
sw r6, r1, r0
lhu r7, r1, r10
rsubi r8, r10, 0x22
sh r7, r0, r8
rsubi r8, r10, 0x26
sh r6, r0, r8
addik r6, r0, _interrupt_handler
addk r6, r6, r23 /* add offset */
sw r6, r1, r0
lhu r7, r1, r10
rsubi r8, r10, 0x12
sh r7, r0, r8
rsubi r8, r10, 0x16
sh r6, r0, r8
/* Check if GOT exist */
addik r21, r23, _got_start
addik r22, r23, _got_end
cmpu r12, r21, r22
beqi r12, 2f /* No GOT table - jump over */
/* Skip last 3 entries plus 1 because of loop boundary below */
addik r22, r22, -0x10
/* Relocate the GOT. */
3: lw r12, r21, r0 /* Load entry */
addk r12, r12, r23 /* Add reloc offset */
sw r12, r21, r0 /* Save entry back */
cmpu r12, r21, r22 /* Check if this cross boundary */
bneid r12, 3b
addik r21. r21, 4
/* Update pointer to GOT */
mfs r20, rpc
addik r20, r20, _GLOBAL_OFFSET_TABLE_ + 8
addk r20, r20, r23
/* Flush caches to ensure consistency */
addik r5, r0, 0
addik r6, r0, XILINX_DCACHE_BYTE_SIZE
bralid r15, flush_cache
nop
2: addi r5, r31, 0 /* gd is initialized in board_r.c */
addi r6, r0, CONFIG_SYS_TEXT_BASE
addi r12, r23, board_init_r
bra r12 /* Jump to relocated code */
.end relocate_code
#endif
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