2 * Copyright (c) 2011 The Chromium OS Authors.
3 * (C) Copyright 2002-2006
4 * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
7 * Sysgo Real-Time Solutions, GmbH <www.elinos.com>
8 * Marius Groeger <mgroeger@sysgo.de>
10 * SPDX-License-Identifier: GPL-2.0+
15 #include <environment.h>
27 #include <status_led.h>
32 #ifdef CONFIG_MACH_TYPE
33 #include <asm/mach-types.h>
35 #if defined(CONFIG_MP) && defined(CONFIG_PPC)
39 #include <asm/sections.h>
41 #include <linux/errno.h>
44 * Pointer to initial global data area
46 * Here we initialize it if needed.
48 #ifdef XTRN_DECLARE_GLOBAL_DATA_PTR
49 #undef XTRN_DECLARE_GLOBAL_DATA_PTR
50 #define XTRN_DECLARE_GLOBAL_DATA_PTR /* empty = allocate here */
51 DECLARE_GLOBAL_DATA_PTR = (gd_t *)(CONFIG_SYS_INIT_GD_ADDR);
53 DECLARE_GLOBAL_DATA_PTR;
57 * TODO(sjg@chromium.org): IMO this code should be
58 * refactored to a single function, something like:
60 * void led_set_state(enum led_colour_t colour, int on);
62 /************************************************************************
63 * Coloured LED functionality
64 ************************************************************************
65 * May be supplied by boards if desired
67 __weak void coloured_LED_init(void) {}
68 __weak void red_led_on(void) {}
69 __weak void red_led_off(void) {}
70 __weak void green_led_on(void) {}
71 __weak void green_led_off(void) {}
72 __weak void yellow_led_on(void) {}
73 __weak void yellow_led_off(void) {}
74 __weak void blue_led_on(void) {}
75 __weak void blue_led_off(void) {}
78 * Why is gd allocated a register? Prior to reloc it might be better to
79 * just pass it around to each function in this file?
81 * After reloc one could argue that it is hardly used and doesn't need
82 * to be in a register. Or if it is it should perhaps hold pointers to all
83 * global data for all modules, so that post-reloc we can avoid the massive
84 * literal pool we get on ARM. Or perhaps just encourage each module to use
88 #if defined(CONFIG_WATCHDOG) || defined(CONFIG_HW_WATCHDOG)
89 static int init_func_watchdog_init(void)
91 # if defined(CONFIG_HW_WATCHDOG) && \
92 (defined(CONFIG_M68K) || defined(CONFIG_MICROBLAZE) || \
93 defined(CONFIG_SH) || defined(CONFIG_AT91SAM9_WATCHDOG) || \
94 defined(CONFIG_DESIGNWARE_WATCHDOG) || \
95 defined(CONFIG_IMX_WATCHDOG))
97 puts(" Watchdog enabled\n");
104 int init_func_watchdog_reset(void)
110 #endif /* CONFIG_WATCHDOG */
112 __weak void board_add_ram_info(int use_default)
114 /* please define platform specific board_add_ram_info() */
117 static int init_baud_rate(void)
119 gd->baudrate = env_get_ulong("baudrate", 10, CONFIG_BAUDRATE);
123 static int display_text_info(void)
125 #if !defined(CONFIG_SANDBOX) && !defined(CONFIG_EFI_APP)
126 ulong bss_start, bss_end, text_base;
128 bss_start = (ulong)&__bss_start;
129 bss_end = (ulong)&__bss_end;
131 #ifdef CONFIG_SYS_TEXT_BASE
132 text_base = CONFIG_SYS_TEXT_BASE;
134 text_base = CONFIG_SYS_MONITOR_BASE;
137 debug("U-Boot code: %08lX -> %08lX BSS: -> %08lX\n",
138 text_base, bss_start, bss_end);
144 static int announce_dram_init(void)
150 static int show_dram_config(void)
152 unsigned long long size;
154 #ifdef CONFIG_NR_DRAM_BANKS
157 debug("\nRAM Configuration:\n");
158 for (i = size = 0; i < CONFIG_NR_DRAM_BANKS; i++) {
159 size += gd->bd->bi_dram[i].size;
160 debug("Bank #%d: %llx ", i,
161 (unsigned long long)(gd->bd->bi_dram[i].start));
163 print_size(gd->bd->bi_dram[i].size, "\n");
171 print_size(size, "");
172 board_add_ram_info(0);
178 __weak int dram_init_banksize(void)
180 #if defined(CONFIG_NR_DRAM_BANKS) && defined(CONFIG_SYS_SDRAM_BASE)
181 gd->bd->bi_dram[0].start = CONFIG_SYS_SDRAM_BASE;
182 gd->bd->bi_dram[0].size = get_effective_memsize();
188 #if defined(CONFIG_SYS_I2C)
189 static int init_func_i2c(void)
192 #ifdef CONFIG_SYS_I2C
195 i2c_init(CONFIG_SYS_I2C_SPEED, CONFIG_SYS_I2C_SLAVE);
202 #if defined(CONFIG_VID)
203 __weak int init_func_vid(void)
209 #if defined(CONFIG_HARD_SPI)
210 static int init_func_spi(void)
219 static int setup_mon_len(void)
221 #if defined(__ARM__) || defined(__MICROBLAZE__)
222 gd->mon_len = (ulong)&__bss_end - (ulong)_start;
223 #elif defined(CONFIG_SANDBOX) || defined(CONFIG_EFI_APP)
224 gd->mon_len = (ulong)&_end - (ulong)_init;
225 #elif defined(CONFIG_NIOS2) || defined(CONFIG_XTENSA)
226 gd->mon_len = CONFIG_SYS_MONITOR_LEN;
227 #elif defined(CONFIG_NDS32) || defined(CONFIG_SH) || defined(CONFIG_RISCV)
228 gd->mon_len = (ulong)(&__bss_end) - (ulong)(&_start);
229 #elif defined(CONFIG_SYS_MONITOR_BASE)
230 /* TODO: use (ulong)&__bss_end - (ulong)&__text_start; ? */
231 gd->mon_len = (ulong)&__bss_end - CONFIG_SYS_MONITOR_BASE;
236 __weak int arch_cpu_init(void)
241 __weak int mach_cpu_init(void)
246 /* Get the top of usable RAM */
247 __weak ulong board_get_usable_ram_top(ulong total_size)
249 #ifdef CONFIG_SYS_SDRAM_BASE
251 * Detect whether we have so much RAM that it goes past the end of our
252 * 32-bit address space. If so, clip the usable RAM so it doesn't.
254 if (gd->ram_top < CONFIG_SYS_SDRAM_BASE)
256 * Will wrap back to top of 32-bit space when reservations
264 static int setup_dest_addr(void)
266 debug("Monitor len: %08lX\n", gd->mon_len);
268 * Ram is setup, size stored in gd !!
270 debug("Ram size: %08lX\n", (ulong)gd->ram_size);
271 #if defined(CONFIG_SYS_MEM_TOP_HIDE)
273 * Subtract specified amount of memory to hide so that it won't
274 * get "touched" at all by U-Boot. By fixing up gd->ram_size
275 * the Linux kernel should now get passed the now "corrected"
276 * memory size and won't touch it either. This should work
277 * for arch/ppc and arch/powerpc. Only Linux board ports in
278 * arch/powerpc with bootwrapper support, that recalculate the
279 * memory size from the SDRAM controller setup will have to
282 gd->ram_size -= CONFIG_SYS_MEM_TOP_HIDE;
284 #ifdef CONFIG_SYS_SDRAM_BASE
285 gd->ram_top = CONFIG_SYS_SDRAM_BASE;
287 gd->ram_top += get_effective_memsize();
288 gd->ram_top = board_get_usable_ram_top(gd->mon_len);
289 gd->relocaddr = gd->ram_top;
290 debug("Ram top: %08lX\n", (ulong)gd->ram_top);
291 #if defined(CONFIG_MP) && (defined(CONFIG_MPC86xx) || defined(CONFIG_E500))
293 * We need to make sure the location we intend to put secondary core
294 * boot code is reserved and not used by any part of u-boot
296 if (gd->relocaddr > determine_mp_bootpg(NULL)) {
297 gd->relocaddr = determine_mp_bootpg(NULL);
298 debug("Reserving MP boot page to %08lx\n", gd->relocaddr);
305 /* reserve protected RAM */
306 static int reserve_pram(void)
310 reg = env_get_ulong("pram", 10, CONFIG_PRAM);
311 gd->relocaddr -= (reg << 10); /* size is in kB */
312 debug("Reserving %ldk for protected RAM at %08lx\n", reg,
316 #endif /* CONFIG_PRAM */
318 /* Round memory pointer down to next 4 kB limit */
319 static int reserve_round_4k(void)
321 gd->relocaddr &= ~(4096 - 1);
326 __weak int reserve_mmu(void)
328 #if !(defined(CONFIG_SYS_ICACHE_OFF) && defined(CONFIG_SYS_DCACHE_OFF))
329 /* reserve TLB table */
330 gd->arch.tlb_size = PGTABLE_SIZE;
331 gd->relocaddr -= gd->arch.tlb_size;
333 /* round down to next 64 kB limit */
334 gd->relocaddr &= ~(0x10000 - 1);
336 gd->arch.tlb_addr = gd->relocaddr;
337 debug("TLB table from %08lx to %08lx\n", gd->arch.tlb_addr,
338 gd->arch.tlb_addr + gd->arch.tlb_size);
340 #ifdef CONFIG_SYS_MEM_RESERVE_SECURE
342 * Record allocated tlb_addr in case gd->tlb_addr to be overwritten
343 * with location within secure ram.
345 gd->arch.tlb_allocated = gd->arch.tlb_addr;
353 static int reserve_video(void)
355 #ifdef CONFIG_DM_VIDEO
359 addr = gd->relocaddr;
360 ret = video_reserve(&addr);
363 gd->relocaddr = addr;
364 #elif defined(CONFIG_LCD)
365 # ifdef CONFIG_FB_ADDR
366 gd->fb_base = CONFIG_FB_ADDR;
368 /* reserve memory for LCD display (always full pages) */
369 gd->relocaddr = lcd_setmem(gd->relocaddr);
370 gd->fb_base = gd->relocaddr;
371 # endif /* CONFIG_FB_ADDR */
372 #elif defined(CONFIG_VIDEO) && \
373 (!defined(CONFIG_PPC)) && \
374 !defined(CONFIG_ARM) && !defined(CONFIG_X86) && \
375 !defined(CONFIG_M68K)
376 /* reserve memory for video display (always full pages) */
377 gd->relocaddr = video_setmem(gd->relocaddr);
378 gd->fb_base = gd->relocaddr;
384 static int reserve_trace(void)
387 gd->relocaddr -= CONFIG_TRACE_BUFFER_SIZE;
388 gd->trace_buff = map_sysmem(gd->relocaddr, CONFIG_TRACE_BUFFER_SIZE);
389 debug("Reserving %dk for trace data at: %08lx\n",
390 CONFIG_TRACE_BUFFER_SIZE >> 10, gd->relocaddr);
396 static int reserve_uboot(void)
399 * reserve memory for U-Boot code, data & bss
400 * round down to next 4 kB limit
402 gd->relocaddr -= gd->mon_len;
403 gd->relocaddr &= ~(4096 - 1);
404 #if defined(CONFIG_E500) || defined(CONFIG_MIPS)
405 /* round down to next 64 kB limit so that IVPR stays aligned */
406 gd->relocaddr &= ~(65536 - 1);
409 debug("Reserving %ldk for U-Boot at: %08lx\n", gd->mon_len >> 10,
412 gd->start_addr_sp = gd->relocaddr;
417 /* reserve memory for malloc() area */
418 static int reserve_malloc(void)
420 gd->start_addr_sp = gd->start_addr_sp - TOTAL_MALLOC_LEN;
421 debug("Reserving %dk for malloc() at: %08lx\n",
422 TOTAL_MALLOC_LEN >> 10, gd->start_addr_sp);
426 /* (permanently) allocate a Board Info struct */
427 static int reserve_board(void)
430 gd->start_addr_sp -= sizeof(bd_t);
431 gd->bd = (bd_t *)map_sysmem(gd->start_addr_sp, sizeof(bd_t));
432 memset(gd->bd, '\0', sizeof(bd_t));
433 debug("Reserving %zu Bytes for Board Info at: %08lx\n",
434 sizeof(bd_t), gd->start_addr_sp);
439 static int setup_machine(void)
441 #ifdef CONFIG_MACH_TYPE
442 gd->bd->bi_arch_number = CONFIG_MACH_TYPE; /* board id for Linux */
447 static int reserve_global_data(void)
449 gd->start_addr_sp -= sizeof(gd_t);
450 gd->new_gd = (gd_t *)map_sysmem(gd->start_addr_sp, sizeof(gd_t));
451 debug("Reserving %zu Bytes for Global Data at: %08lx\n",
452 sizeof(gd_t), gd->start_addr_sp);
456 static int reserve_fdt(void)
458 #ifndef CONFIG_OF_EMBED
460 * If the device tree is sitting immediately above our image then we
461 * must relocate it. If it is embedded in the data section, then it
462 * will be relocated with other data.
465 gd->fdt_size = ALIGN(fdt_totalsize(gd->fdt_blob) + 0x1000, 32);
467 gd->start_addr_sp -= gd->fdt_size;
468 gd->new_fdt = map_sysmem(gd->start_addr_sp, gd->fdt_size);
469 debug("Reserving %lu Bytes for FDT at: %08lx\n",
470 gd->fdt_size, gd->start_addr_sp);
477 static int reserve_bootstage(void)
479 #ifdef CONFIG_BOOTSTAGE
480 int size = bootstage_get_size();
482 gd->start_addr_sp -= size;
483 gd->new_bootstage = map_sysmem(gd->start_addr_sp, size);
484 debug("Reserving %#x Bytes for bootstage at: %08lx\n", size,
491 __weak int arch_reserve_stacks(void)
496 static int reserve_stacks(void)
498 /* make stack pointer 16-byte aligned */
499 gd->start_addr_sp -= 16;
500 gd->start_addr_sp &= ~0xf;
503 * let the architecture-specific code tailor gd->start_addr_sp and
506 return arch_reserve_stacks();
509 static int display_new_sp(void)
511 debug("New Stack Pointer is: %08lx\n", gd->start_addr_sp);
516 #if defined(CONFIG_M68K) || defined(CONFIG_MIPS) || defined(CONFIG_PPC) || \
518 static int setup_board_part1(void)
523 * Save local variables to board info struct
525 bd->bi_memstart = CONFIG_SYS_SDRAM_BASE; /* start of memory */
526 bd->bi_memsize = gd->ram_size; /* size in bytes */
528 #ifdef CONFIG_SYS_SRAM_BASE
529 bd->bi_sramstart = CONFIG_SYS_SRAM_BASE; /* start of SRAM */
530 bd->bi_sramsize = CONFIG_SYS_SRAM_SIZE; /* size of SRAM */
533 #if defined(CONFIG_E500) || defined(CONFIG_MPC86xx)
534 bd->bi_immr_base = CONFIG_SYS_IMMR; /* base of IMMR register */
536 #if defined(CONFIG_M68K)
537 bd->bi_mbar_base = CONFIG_SYS_MBAR; /* base of internal registers */
539 #if defined(CONFIG_MPC83xx)
540 bd->bi_immrbar = CONFIG_SYS_IMMR;
547 #if defined(CONFIG_PPC) || defined(CONFIG_M68K)
548 static int setup_board_part2(void)
552 bd->bi_intfreq = gd->cpu_clk; /* Internal Freq, in Hz */
553 bd->bi_busfreq = gd->bus_clk; /* Bus Freq, in Hz */
554 #if defined(CONFIG_CPM2)
555 bd->bi_cpmfreq = gd->arch.cpm_clk;
556 bd->bi_brgfreq = gd->arch.brg_clk;
557 bd->bi_sccfreq = gd->arch.scc_clk;
558 bd->bi_vco = gd->arch.vco_out;
559 #endif /* CONFIG_CPM2 */
560 #if defined(CONFIG_M68K) && defined(CONFIG_PCI)
561 bd->bi_pcifreq = gd->pci_clk;
563 #if defined(CONFIG_EXTRA_CLOCK)
564 bd->bi_inpfreq = gd->arch.inp_clk; /* input Freq in Hz */
565 bd->bi_vcofreq = gd->arch.vco_clk; /* vco Freq in Hz */
566 bd->bi_flbfreq = gd->arch.flb_clk; /* flexbus Freq in Hz */
574 static int init_post(void)
576 post_bootmode_init();
577 post_run(NULL, POST_ROM | post_bootmode_get(0));
583 static int reloc_fdt(void)
585 #ifndef CONFIG_OF_EMBED
586 if (gd->flags & GD_FLG_SKIP_RELOC)
589 memcpy(gd->new_fdt, gd->fdt_blob, gd->fdt_size);
590 gd->fdt_blob = gd->new_fdt;
597 static int reloc_bootstage(void)
599 #ifdef CONFIG_BOOTSTAGE
600 if (gd->flags & GD_FLG_SKIP_RELOC)
602 if (gd->new_bootstage) {
603 int size = bootstage_get_size();
605 debug("Copying bootstage from %p to %p, size %x\n",
606 gd->bootstage, gd->new_bootstage, size);
607 memcpy(gd->new_bootstage, gd->bootstage, size);
608 gd->bootstage = gd->new_bootstage;
615 static int setup_reloc(void)
617 if (gd->flags & GD_FLG_SKIP_RELOC) {
618 debug("Skipping relocation due to flag\n");
622 #ifdef CONFIG_SYS_TEXT_BASE
624 gd->reloc_off = gd->relocaddr - (unsigned long)__image_copy_start;
625 #elif defined(CONFIG_M68K)
627 * On all ColdFire arch cpu, monitor code starts always
628 * just after the default vector table location, so at 0x400
630 gd->reloc_off = gd->relocaddr - (CONFIG_SYS_TEXT_BASE + 0x400);
632 gd->reloc_off = gd->relocaddr - CONFIG_SYS_TEXT_BASE;
635 memcpy(gd->new_gd, (char *)gd, sizeof(gd_t));
637 debug("Relocation Offset is: %08lx\n", gd->reloc_off);
638 debug("Relocating to %08lx, new gd at %08lx, sp at %08lx\n",
639 gd->relocaddr, (ulong)map_to_sysmem(gd->new_gd),
645 #ifdef CONFIG_OF_BOARD_FIXUP
646 static int fix_fdt(void)
648 return board_fix_fdt((void *)gd->fdt_blob);
652 /* ARM calls relocate_code from its crt0.S */
653 #if !defined(CONFIG_ARM) && !defined(CONFIG_SANDBOX) && \
654 !CONFIG_IS_ENABLED(X86_64)
656 static int jump_to_copy(void)
658 if (gd->flags & GD_FLG_SKIP_RELOC)
661 * x86 is special, but in a nice way. It uses a trampoline which
662 * enables the dcache if possible.
664 * For now, other archs use relocate_code(), which is implemented
665 * similarly for all archs. When we do generic relocation, hopefully
666 * we can make all archs enable the dcache prior to relocation.
668 #if defined(CONFIG_X86) || defined(CONFIG_ARC)
670 * SDRAM and console are now initialised. The final stack can now
671 * be setup in SDRAM. Code execution will continue in Flash, but
672 * with the stack in SDRAM and Global Data in temporary memory
675 arch_setup_gd(gd->new_gd);
676 board_init_f_r_trampoline(gd->start_addr_sp);
678 relocate_code(gd->start_addr_sp, gd->new_gd, gd->relocaddr);
685 /* Record the board_init_f() bootstage (after arch_cpu_init()) */
686 static int initf_bootstage(void)
688 bool from_spl = IS_ENABLED(CONFIG_SPL_BOOTSTAGE) &&
689 IS_ENABLED(CONFIG_BOOTSTAGE_STASH);
692 ret = bootstage_init(!from_spl);
696 const void *stash = map_sysmem(CONFIG_BOOTSTAGE_STASH_ADDR,
697 CONFIG_BOOTSTAGE_STASH_SIZE);
699 ret = bootstage_unstash(stash, CONFIG_BOOTSTAGE_STASH_SIZE);
700 if (ret && ret != -ENOENT) {
701 debug("Failed to unstash bootstage: err=%d\n", ret);
706 bootstage_mark_name(BOOTSTAGE_ID_START_UBOOT_F, "board_init_f");
711 static int initf_console_record(void)
713 #if defined(CONFIG_CONSOLE_RECORD) && CONFIG_VAL(SYS_MALLOC_F_LEN)
714 return console_record_init();
720 static int initf_dm(void)
722 #if defined(CONFIG_DM) && CONFIG_VAL(SYS_MALLOC_F_LEN)
725 bootstage_start(BOOTSTATE_ID_ACCUM_DM_F, "dm_f");
726 ret = dm_init_and_scan(true);
727 bootstage_accum(BOOTSTATE_ID_ACCUM_DM_F);
731 #ifdef CONFIG_TIMER_EARLY
732 ret = dm_timer_init();
740 /* Architecture-specific memory reservation */
741 __weak int reserve_arch(void)
746 __weak int arch_cpu_init_dm(void)
751 static const init_fnc_t init_sequence_f[] = {
753 #ifdef CONFIG_OF_CONTROL
761 initf_bootstage, /* uses its own timer, so does not need DM */
762 initf_console_record,
763 #if defined(CONFIG_HAVE_FSP)
766 arch_cpu_init, /* basic arch cpu dependent setup */
767 mach_cpu_init, /* SoC/machine dependent CPU setup */
770 #if defined(CONFIG_BOARD_EARLY_INIT_F)
773 #if defined(CONFIG_PPC) || defined(CONFIG_SYS_FSL_CLK) || defined(CONFIG_M68K)
774 /* get CPU and bus clocks according to the environment variable */
775 get_clocks, /* get CPU and bus clocks (etc.) */
777 #if !defined(CONFIG_M68K)
778 timer_init, /* initialize timer */
780 #if defined(CONFIG_BOARD_POSTCLK_INIT)
783 env_init, /* initialize environment */
784 init_baud_rate, /* initialze baudrate settings */
785 serial_init, /* serial communications setup */
786 console_init_f, /* stage 1 init of console */
787 display_options, /* say that we are here */
788 display_text_info, /* show debugging info if required */
789 #if defined(CONFIG_PPC) || defined(CONFIG_SH) || defined(CONFIG_X86)
792 #if defined(CONFIG_DISPLAY_CPUINFO)
793 print_cpuinfo, /* display cpu info (and speed) */
795 #if defined(CONFIG_DTB_RESELECT)
798 #if defined(CONFIG_DISPLAY_BOARDINFO)
801 INIT_FUNC_WATCHDOG_INIT
802 #if defined(CONFIG_MISC_INIT_F)
805 INIT_FUNC_WATCHDOG_RESET
806 #if defined(CONFIG_SYS_I2C)
809 #if defined(CONFIG_VID) && !defined(CONFIG_SPL)
812 #if defined(CONFIG_HARD_SPI)
816 dram_init, /* configure available RAM banks */
820 INIT_FUNC_WATCHDOG_RESET
821 #if defined(CONFIG_SYS_DRAM_TEST)
823 #endif /* CONFIG_SYS_DRAM_TEST */
824 INIT_FUNC_WATCHDOG_RESET
829 INIT_FUNC_WATCHDOG_RESET
831 * Now that we have DRAM mapped and working, we can
832 * relocate the code and continue running from DRAM.
834 * Reserve memory at end of RAM for (top down in that order):
835 * - area that won't get touched by U-Boot and Linux (optional)
836 * - kernel log buffer
840 * - board info struct
863 #if defined(CONFIG_M68K) || defined(CONFIG_MIPS) || defined(CONFIG_PPC) || \
867 #if defined(CONFIG_PPC) || defined(CONFIG_M68K)
868 INIT_FUNC_WATCHDOG_RESET
872 #ifdef CONFIG_OF_BOARD_FIXUP
875 INIT_FUNC_WATCHDOG_RESET
879 #if defined(CONFIG_X86) || defined(CONFIG_ARC)
884 #if defined(CONFIG_XTENSA)
887 #if !defined(CONFIG_ARM) && !defined(CONFIG_SANDBOX) && \
888 !CONFIG_IS_ENABLED(X86_64)
894 void board_init_f(ulong boot_flags)
896 gd->flags = boot_flags;
897 gd->have_console = 0;
899 if (initcall_run_list(init_sequence_f))
902 #if !defined(CONFIG_ARM) && !defined(CONFIG_SANDBOX) && \
903 !defined(CONFIG_EFI_APP) && !CONFIG_IS_ENABLED(X86_64) && \
905 /* NOTREACHED - jump_to_copy() does not return */
910 #if defined(CONFIG_X86) || defined(CONFIG_ARC)
912 * For now this code is only used on x86.
914 * init_sequence_f_r is the list of init functions which are run when
915 * U-Boot is executing from Flash with a semi-limited 'C' environment.
916 * The following limitations must be considered when implementing an
918 * - 'static' variables are read-only
919 * - Global Data (gd->xxx) is read/write
921 * The '_f_r' sequence must, as a minimum, copy U-Boot to RAM (if
922 * supported). It _should_, if possible, copy global data to RAM and
923 * initialise the CPU caches (to speed up the relocation process)
925 * NOTE: At present only x86 uses this route, but it is intended that
926 * all archs will move to this when generic relocation is implemented.
928 static const init_fnc_t init_sequence_f_r[] = {
929 #if !CONFIG_IS_ENABLED(X86_64)
936 void board_init_f_r(void)
938 if (initcall_run_list(init_sequence_f_r))
942 * The pre-relocation drivers may be using memory that has now gone
943 * away. Mark serial as unavailable - this will fall back to the debug
946 * Do the same with log drivers since the memory may not be available.
948 gd->flags &= ~(GD_FLG_SERIAL_READY | GD_FLG_LOG_READY);
954 * U-Boot has been copied into SDRAM, the BSS has been cleared etc.
955 * Transfer execution from Flash to RAM by calculating the address
956 * of the in-RAM copy of board_init_r() and calling it
958 (board_init_r + gd->reloc_off)((gd_t *)gd, gd->relocaddr);
960 /* NOTREACHED - board_init_r() does not return */
963 #endif /* CONFIG_X86 */