| /* |
| * Startup Code for MIPS32 CPU-core |
| * |
| * Copyright (c) 2003 Wolfgang Denk <wd@denx.de> |
| * |
| * SPDX-License-Identifier: GPL-2.0+ |
| */ |
| |
| #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: |
| /* U-boot entry point */ |
| b reset |
| nop |
| |
| .org 0x10 |
| #if defined(CONFIG_SYS_XWAY_EBU_BOOTCFG) |
| /* |
| * Almost all Lantiq XWAY SoC devices have an external bus unit (EBU) to |
| * access external NOR flashes. If the board boots from NOR flash the |
| * internal BootROM does a blind read at address 0xB0000010 to read the |
| * initial configuration for that EBU in order to access the flash |
| * device with correct parameters. This config option is board-specific. |
| */ |
| .word CONFIG_SYS_XWAY_EBU_BOOTCFG |
| .word 0x0 |
| #elif defined(CONFIG_QEMU_MALTA) |
| /* |
| * Linux expects the Board ID here. |
| */ |
| .word 0x00000420 # 0x420 (Malta Board with CoreLV) |
| .word 0x00000000 |
| #endif |
| |
| .org 0x200 |
| /* TLB refill, 32 bit task */ |
| 1: b 1b |
| nop |
| |
| .org 0x280 |
| /* XTLB refill, 64 bit task */ |
| 1: b 1b |
| nop |
| |
| .org 0x300 |
| /* Cache error exception */ |
| 1: b 1b |
| nop |
| |
| .org 0x380 |
| /* General exception */ |
| 1: b 1b |
| nop |
| |
| .org 0x400 |
| /* Catch interrupt exceptions */ |
| 1: b 1b |
| nop |
| |
| .org 0x480 |
| /* EJTAG debug exception */ |
| 1: b 1b |
| nop |
| |
| .align 4 |
| reset: |
| |
| /* Clear watch registers */ |
| mtc0 zero, CP0_WATCHLO |
| mtc0 zero, CP0_WATCHHI |
| |
| /* WP(Watch Pending), SW0/1 should be cleared */ |
| mtc0 zero, CP0_CAUSE |
| |
| setup_c0_status 0 0 |
| |
| /* Init Timer */ |
| mtc0 zero, CP0_COUNT |
| mtc0 zero, CP0_COMPARE |
| |
| #ifndef CONFIG_SKIP_LOWLEVEL_INIT |
| /* CONFIG0 register */ |
| li t0, CONF_CM_UNCACHED |
| mtc0 t0, CP0_CONFIG |
| #endif |
| |
| /* Initialize $gp */ |
| bal 1f |
| nop |
| .word _gp |
| 1: |
| lw gp, 0(ra) |
| |
| #ifndef CONFIG_SKIP_LOWLEVEL_INIT |
| /* Initialize any external memory */ |
| la t9, lowlevel_init |
| jalr t9 |
| nop |
| |
| /* Initialize caches... */ |
| la t9, mips_cache_reset |
| jalr t9 |
| nop |
| |
| /* ... and enable them */ |
| li t0, CONFIG_SYS_MIPS_CACHE_MODE |
| mtc0 t0, CP0_CONFIG |
| #endif |
| |
| /* Set up temporary stack */ |
| li sp, CONFIG_SYS_SDRAM_BASE + CONFIG_SYS_INIT_SP_OFFSET |
| |
| la 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 |
| |
| li t0, CONFIG_SYS_MONITOR_BASE |
| sub s1, s2, t0 # s1 <-- relocation offset |
| |
| la t3, in_ram |
| lw t2, -12(t3) # t2 <-- __image_copy_end |
| move t1, a2 |
| |
| add gp, s1 # adjust gp |
| |
| /* |
| * t0 = source address |
| * t1 = target address |
| * t2 = source end address |
| */ |
| 1: |
| lw t3, 0(t0) |
| sw t3, 0(t1) |
| addu t0, 4 |
| blt t0, t2, 1b |
| addu t1, 4 |
| |
| /* If caches were enabled, we would have to flush them here. */ |
| sub a1, t1, s2 # a1 <-- size |
| la t9, flush_cache |
| jalr t9 |
| move a0, s2 # a0 <-- destination address |
| |
| /* Jump to where we've relocated ourselves */ |
| addi t0, s2, in_ram - _start |
| jr t0 |
| nop |
| |
| .word __rel_dyn_end |
| .word __rel_dyn_start |
| .word __image_copy_end |
| .word _GLOBAL_OFFSET_TABLE_ |
| .word 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. |
| */ |
| lw t3, -4(t0) # t3 <-- num_got_entries |
| lw t8, -8(t0) # t8 <-- _GLOBAL_OFFSET_TABLE_ |
| add t8, s1 # t8 now holds relocated _G_O_T_ |
| addi t8, t8, 8 # skipping first two entries |
| li t2, 2 |
| 1: |
| lw t1, 0(t8) |
| beqz t1, 2f |
| add t1, s1 |
| sw t1, 0(t8) |
| 2: |
| addi t2, 1 |
| blt t2, t3, 1b |
| addi t8, 4 |
| |
| /* Update dynamic relocations */ |
| lw t1, -16(t0) # t1 <-- __rel_dyn_start |
| lw t2, -20(t0) # t2 <-- __rel_dyn_end |
| |
| b 2f # skip first reserved entry |
| addi t1, 8 |
| |
| 1: |
| lw t8, -4(t1) # t8 <-- relocation info |
| |
| li t3, 3 |
| bne t8, t3, 2f # skip non R_MIPS_REL32 entries |
| nop |
| |
| lw t3, -8(t1) # t3 <-- location to fix up in FLASH |
| |
| lw t8, 0(t3) # t8 <-- original pointer |
| add t8, s1 # t8 <-- adjusted pointer |
| |
| add t3, s1 # t3 <-- location to fix up in RAM |
| sw t8, 0(t3) |
| |
| 2: |
| blt t1, t2, 1b |
| addi t1, 8 # each rel.dyn entry is 8 bytes |
| |
| /* |
| * Clear BSS |
| * |
| * GOT is now relocated. Thus __bss_start and __bss_end can be |
| * accessed directly via $gp. |
| */ |
| la t1, __bss_start # t1 <-- __bss_start |
| la t2, __bss_end # t2 <-- __bss_end |
| |
| 1: |
| sw zero, 0(t1) |
| blt t1, t2, 1b |
| addi t1, 4 |
| |
| move a0, s0 # a0 <-- gd |
| la t9, board_init_r |
| jr t9 |
| move a1, s2 |
| |
| .end relocate_code |