/* * Startup Code for MIPS32 CPU-core * * Copyright (c) 2003 Wolfgang Denk * * SPDX-License-Identifier: GPL-2.0+ */ #include #include #include #include #include #ifndef CONFIG_SYS_MIPS_CACHE_MODE #define CONFIG_SYS_MIPS_CACHE_MODE CONF_CM_CACHABLE_NONCOHERENT #endif #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 /* * 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 ENTRY(_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_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 STATUS_SET 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, force pointer sized 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 PTRLOG bal 1f nop PTR _gp 1: PTR_L gp, 0(ra) #ifndef CONFIG_SKIP_LOWLEVEL_INIT /* Initialize any external memory */ PTR_LA t9, lowlevel_init jalr t9 nop /* Initialize caches... */ PTR_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 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 #ifdef CONFIG_SYS_MALLOC_F_LEN li t2, CONFIG_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) blt t0, t1, 1b PTR_ADDIU t0, PTRSIZE #ifdef CONFIG_SYS_MALLOC_F_LEN PTR_S sp, GD_MALLOC_BASE(k0) # gd->malloc_base offset #endif move a0, zero # a0 <-- boot_flags = 0 PTR_LA t9, board_init_f jr t9 move ra, zero END(_start) /* * 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 */ ENTRY(relocate_code) move sp, a0 # set new stack pointer move fp, sp move s0, a1 # save gd in s0 move s2, a2 # save destination address in s2 PTR_LI t0, CONFIG_SYS_MONITOR_BASE PTR_SUB s1, s2, t0 # s1 <-- relocation offset PTR_LA t3, in_ram PTR_L t2, -(3 * PTRSIZE)(t3) # t2 <-- __image_copy_end move t1, a2 PTR_ADD gp, s1 # adjust gp /* * t0 = source address * t1 = target address * t2 = source end address */ 1: PTR_L t3, 0(t0) PTR_S t3, 0(t1) PTR_ADDU t0, PTRSIZE blt t0, t2, 1b PTR_ADDU t1, PTRSIZE /* If caches were enabled, we would have to flush them here. */ PTR_SUB a1, t1, s2 # a1 <-- size PTR_LA t9, flush_cache jalr t9 move a0, s2 # a0 <-- destination address /* Jump to where we've relocated ourselves */ PTR_ADDIU t0, s2, in_ram - _start jr t0 nop PTR __rel_dyn_end PTR __rel_dyn_start PTR __image_copy_end PTR _GLOBAL_OFFSET_TABLE_ PTR 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. */ PTR_L t3, -(1 * PTRSIZE)(t0) # t3 <-- num_got_entries PTR_L t8, -(2 * PTRSIZE)(t0) # t8 <-- _GLOBAL_OFFSET_TABLE_ PTR_ADD t8, s1 # t8 now holds relocated _G_O_T_ PTR_ADDIU t8, t8, 2 * PTRSIZE # skipping first two entries PTR_LI t2, 2 1: PTR_L t1, 0(t8) beqz t1, 2f PTR_ADD t1, s1 PTR_S t1, 0(t8) 2: PTR_ADDIU t2, 1 blt t2, t3, 1b PTR_ADDIU t8, PTRSIZE /* Update dynamic relocations */ PTR_L t1, -(4 * PTRSIZE)(t0) # t1 <-- __rel_dyn_start PTR_L t2, -(5 * PTRSIZE)(t0) # t2 <-- __rel_dyn_end b 2f # skip first reserved entry PTR_ADDIU t1, 2 * PTRSIZE 1: lw t8, -4(t1) # t8 <-- relocation info PTR_LI t3, MIPS_RELOC bne t8, t3, 2f # skip non-MIPS_RELOC entries nop PTR_L t3, -(2 * PTRSIZE)(t1) # t3 <-- location to fix up in FLASH PTR_L t8, 0(t3) # t8 <-- original pointer PTR_ADD t8, s1 # t8 <-- adjusted pointer PTR_ADD t3, s1 # t3 <-- location to fix up in RAM PTR_S t8, 0(t3) 2: blt t1, t2, 1b PTR_ADDIU t1, 2 * PTRSIZE # each rel.dyn entry is 2*PTRSIZE bytes /* * Clear BSS * * GOT is now relocated. Thus __bss_start and __bss_end can be * accessed directly via $gp. */ PTR_LA t1, __bss_start # t1 <-- __bss_start PTR_LA t2, __bss_end # t2 <-- __bss_end 1: PTR_S zero, 0(t1) blt t1, t2, 1b PTR_ADDIU t1, PTRSIZE move a0, s0 # a0 <-- gd move a1, s2 PTR_LA t9, board_init_r jr t9 move ra, zero END(relocate_code)