1 // SPDX-License-Identifier: GPL-2.0+
3 * Copyright (c) 2011 The Chromium OS Authors.
4 * (C) Copyright 2002-2006
5 * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
8 * Sysgo Real-Time Solutions, GmbH <www.elinos.com>
9 * Marius Groeger <mgroeger@sysgo.de>
14 #include <environment.h>
26 #include <status_led.h>
31 #ifdef CONFIG_MACH_TYPE
32 #include <asm/mach-types.h>
34 #if defined(CONFIG_MP) && defined(CONFIG_PPC)
38 #include <asm/sections.h>
40 #include <linux/errno.h>
43 * Pointer to initial global data area
45 * Here we initialize it if needed.
47 #ifdef XTRN_DECLARE_GLOBAL_DATA_PTR
48 #undef XTRN_DECLARE_GLOBAL_DATA_PTR
49 #define XTRN_DECLARE_GLOBAL_DATA_PTR /* empty = allocate here */
50 DECLARE_GLOBAL_DATA_PTR = (gd_t *)(CONFIG_SYS_INIT_GD_ADDR);
52 DECLARE_GLOBAL_DATA_PTR;
56 * TODO(sjg@chromium.org): IMO this code should be
57 * refactored to a single function, something like:
59 * void led_set_state(enum led_colour_t colour, int on);
61 /************************************************************************
62 * Coloured LED functionality
63 ************************************************************************
64 * May be supplied by boards if desired
66 __weak void coloured_LED_init(void) {}
67 __weak void red_led_on(void) {}
68 __weak void red_led_off(void) {}
69 __weak void green_led_on(void) {}
70 __weak void green_led_off(void) {}
71 __weak void yellow_led_on(void) {}
72 __weak void yellow_led_off(void) {}
73 __weak void blue_led_on(void) {}
74 __weak void blue_led_off(void) {}
77 * Why is gd allocated a register? Prior to reloc it might be better to
78 * just pass it around to each function in this file?
80 * After reloc one could argue that it is hardly used and doesn't need
81 * to be in a register. Or if it is it should perhaps hold pointers to all
82 * global data for all modules, so that post-reloc we can avoid the massive
83 * literal pool we get on ARM. Or perhaps just encourage each module to use
87 #if defined(CONFIG_WATCHDOG) || defined(CONFIG_HW_WATCHDOG)
88 static int init_func_watchdog_init(void)
90 # if defined(CONFIG_HW_WATCHDOG) && \
91 (defined(CONFIG_M68K) || defined(CONFIG_MICROBLAZE) || \
92 defined(CONFIG_SH) || defined(CONFIG_AT91SAM9_WATCHDOG) || \
93 defined(CONFIG_DESIGNWARE_WATCHDOG) || \
94 defined(CONFIG_IMX_WATCHDOG))
96 puts(" Watchdog enabled\n");
103 int init_func_watchdog_reset(void)
109 #endif /* CONFIG_WATCHDOG */
111 __weak void board_add_ram_info(int use_default)
113 /* please define platform specific board_add_ram_info() */
116 static int init_baud_rate(void)
118 gd->baudrate = env_get_ulong("baudrate", 10, CONFIG_BAUDRATE);
122 static int display_text_info(void)
124 #if !defined(CONFIG_SANDBOX) && !defined(CONFIG_EFI_APP)
125 ulong bss_start, bss_end, text_base;
127 bss_start = (ulong)&__bss_start;
128 bss_end = (ulong)&__bss_end;
130 #ifdef CONFIG_SYS_TEXT_BASE
131 text_base = CONFIG_SYS_TEXT_BASE;
133 text_base = CONFIG_SYS_MONITOR_BASE;
136 debug("U-Boot code: %08lX -> %08lX BSS: -> %08lX\n",
137 text_base, bss_start, bss_end);
143 static int announce_dram_init(void)
149 static int show_dram_config(void)
151 unsigned long long size;
153 #ifdef CONFIG_NR_DRAM_BANKS
156 debug("\nRAM Configuration:\n");
157 for (i = size = 0; i < CONFIG_NR_DRAM_BANKS; i++) {
158 size += gd->bd->bi_dram[i].size;
159 debug("Bank #%d: %llx ", i,
160 (unsigned long long)(gd->bd->bi_dram[i].start));
162 print_size(gd->bd->bi_dram[i].size, "\n");
170 print_size(size, "");
171 board_add_ram_info(0);
177 __weak int dram_init_banksize(void)
179 #if defined(CONFIG_NR_DRAM_BANKS) && defined(CONFIG_SYS_SDRAM_BASE)
180 gd->bd->bi_dram[0].start = CONFIG_SYS_SDRAM_BASE;
181 gd->bd->bi_dram[0].size = get_effective_memsize();
187 #if defined(CONFIG_SYS_I2C)
188 static int init_func_i2c(void)
191 #ifdef CONFIG_SYS_I2C
194 i2c_init(CONFIG_SYS_I2C_SPEED, CONFIG_SYS_I2C_SLAVE);
201 #if defined(CONFIG_VID)
202 __weak int init_func_vid(void)
208 #if defined(CONFIG_HARD_SPI)
209 static int init_func_spi(void)
218 static int setup_mon_len(void)
220 #if defined(__ARM__) || defined(__MICROBLAZE__)
221 gd->mon_len = (ulong)&__bss_end - (ulong)_start;
222 #elif defined(CONFIG_SANDBOX) || defined(CONFIG_EFI_APP)
223 gd->mon_len = (ulong)&_end - (ulong)_init;
224 #elif defined(CONFIG_NIOS2) || defined(CONFIG_XTENSA)
225 gd->mon_len = CONFIG_SYS_MONITOR_LEN;
226 #elif defined(CONFIG_NDS32) || defined(CONFIG_SH) || defined(CONFIG_RISCV)
227 gd->mon_len = (ulong)(&__bss_end) - (ulong)(&_start);
228 #elif defined(CONFIG_SYS_MONITOR_BASE)
229 /* TODO: use (ulong)&__bss_end - (ulong)&__text_start; ? */
230 gd->mon_len = (ulong)&__bss_end - CONFIG_SYS_MONITOR_BASE;
235 __weak int arch_cpu_init(void)
240 __weak int mach_cpu_init(void)
245 /* Get the top of usable RAM */
246 __weak ulong board_get_usable_ram_top(ulong total_size)
248 #ifdef CONFIG_SYS_SDRAM_BASE
250 * Detect whether we have so much RAM that it goes past the end of our
251 * 32-bit address space. If so, clip the usable RAM so it doesn't.
253 if (gd->ram_top < CONFIG_SYS_SDRAM_BASE)
255 * Will wrap back to top of 32-bit space when reservations
263 static int setup_dest_addr(void)
265 debug("Monitor len: %08lX\n", gd->mon_len);
267 * Ram is setup, size stored in gd !!
269 debug("Ram size: %08lX\n", (ulong)gd->ram_size);
270 #if defined(CONFIG_SYS_MEM_TOP_HIDE)
272 * Subtract specified amount of memory to hide so that it won't
273 * get "touched" at all by U-Boot. By fixing up gd->ram_size
274 * the Linux kernel should now get passed the now "corrected"
275 * memory size and won't touch it either. This should work
276 * for arch/ppc and arch/powerpc. Only Linux board ports in
277 * arch/powerpc with bootwrapper support, that recalculate the
278 * memory size from the SDRAM controller setup will have to
281 gd->ram_size -= CONFIG_SYS_MEM_TOP_HIDE;
283 #ifdef CONFIG_SYS_SDRAM_BASE
284 gd->ram_top = CONFIG_SYS_SDRAM_BASE;
286 gd->ram_top += get_effective_memsize();
287 gd->ram_top = board_get_usable_ram_top(gd->mon_len);
288 gd->relocaddr = gd->ram_top;
289 debug("Ram top: %08lX\n", (ulong)gd->ram_top);
290 #if defined(CONFIG_MP) && (defined(CONFIG_MPC86xx) || defined(CONFIG_E500))
292 * We need to make sure the location we intend to put secondary core
293 * boot code is reserved and not used by any part of u-boot
295 if (gd->relocaddr > determine_mp_bootpg(NULL)) {
296 gd->relocaddr = determine_mp_bootpg(NULL);
297 debug("Reserving MP boot page to %08lx\n", gd->relocaddr);
304 /* reserve protected RAM */
305 static int reserve_pram(void)
309 reg = env_get_ulong("pram", 10, CONFIG_PRAM);
310 gd->relocaddr -= (reg << 10); /* size is in kB */
311 debug("Reserving %ldk for protected RAM at %08lx\n", reg,
315 #endif /* CONFIG_PRAM */
317 /* Round memory pointer down to next 4 kB limit */
318 static int reserve_round_4k(void)
320 gd->relocaddr &= ~(4096 - 1);
325 __weak int reserve_mmu(void)
327 #if !(defined(CONFIG_SYS_ICACHE_OFF) && defined(CONFIG_SYS_DCACHE_OFF))
328 /* reserve TLB table */
329 gd->arch.tlb_size = PGTABLE_SIZE;
330 gd->relocaddr -= gd->arch.tlb_size;
332 /* round down to next 64 kB limit */
333 gd->relocaddr &= ~(0x10000 - 1);
335 gd->arch.tlb_addr = gd->relocaddr;
336 debug("TLB table from %08lx to %08lx\n", gd->arch.tlb_addr,
337 gd->arch.tlb_addr + gd->arch.tlb_size);
339 #ifdef CONFIG_SYS_MEM_RESERVE_SECURE
341 * Record allocated tlb_addr in case gd->tlb_addr to be overwritten
342 * with location within secure ram.
344 gd->arch.tlb_allocated = gd->arch.tlb_addr;
352 static int reserve_video(void)
354 #ifdef CONFIG_DM_VIDEO
358 addr = gd->relocaddr;
359 ret = video_reserve(&addr);
362 gd->relocaddr = addr;
363 #elif defined(CONFIG_LCD)
364 # ifdef CONFIG_FB_ADDR
365 gd->fb_base = CONFIG_FB_ADDR;
367 /* reserve memory for LCD display (always full pages) */
368 gd->relocaddr = lcd_setmem(gd->relocaddr);
369 gd->fb_base = gd->relocaddr;
370 # endif /* CONFIG_FB_ADDR */
371 #elif defined(CONFIG_VIDEO) && \
372 (!defined(CONFIG_PPC)) && \
373 !defined(CONFIG_ARM) && !defined(CONFIG_X86) && \
374 !defined(CONFIG_M68K)
375 /* reserve memory for video display (always full pages) */
376 gd->relocaddr = video_setmem(gd->relocaddr);
377 gd->fb_base = gd->relocaddr;
383 static int reserve_trace(void)
386 gd->relocaddr -= CONFIG_TRACE_BUFFER_SIZE;
387 gd->trace_buff = map_sysmem(gd->relocaddr, CONFIG_TRACE_BUFFER_SIZE);
388 debug("Reserving %dk for trace data at: %08lx\n",
389 CONFIG_TRACE_BUFFER_SIZE >> 10, gd->relocaddr);
395 static int reserve_uboot(void)
398 * reserve memory for U-Boot code, data & bss
399 * round down to next 4 kB limit
401 gd->relocaddr -= gd->mon_len;
402 gd->relocaddr &= ~(4096 - 1);
403 #if defined(CONFIG_E500) || defined(CONFIG_MIPS)
404 /* round down to next 64 kB limit so that IVPR stays aligned */
405 gd->relocaddr &= ~(65536 - 1);
408 debug("Reserving %ldk for U-Boot at: %08lx\n", gd->mon_len >> 10,
411 gd->start_addr_sp = gd->relocaddr;
416 /* reserve memory for malloc() area */
417 static int reserve_malloc(void)
419 gd->start_addr_sp = gd->start_addr_sp - TOTAL_MALLOC_LEN;
420 debug("Reserving %dk for malloc() at: %08lx\n",
421 TOTAL_MALLOC_LEN >> 10, gd->start_addr_sp);
425 /* (permanently) allocate a Board Info struct */
426 static int reserve_board(void)
429 gd->start_addr_sp -= sizeof(bd_t);
430 gd->bd = (bd_t *)map_sysmem(gd->start_addr_sp, sizeof(bd_t));
431 memset(gd->bd, '\0', sizeof(bd_t));
432 debug("Reserving %zu Bytes for Board Info at: %08lx\n",
433 sizeof(bd_t), gd->start_addr_sp);
438 static int setup_machine(void)
440 #ifdef CONFIG_MACH_TYPE
441 gd->bd->bi_arch_number = CONFIG_MACH_TYPE; /* board id for Linux */
446 static int reserve_global_data(void)
448 gd->start_addr_sp -= sizeof(gd_t);
449 gd->new_gd = (gd_t *)map_sysmem(gd->start_addr_sp, sizeof(gd_t));
450 debug("Reserving %zu Bytes for Global Data at: %08lx\n",
451 sizeof(gd_t), gd->start_addr_sp);
455 static int reserve_fdt(void)
457 #ifndef CONFIG_OF_EMBED
459 * If the device tree is sitting immediately above our image then we
460 * must relocate it. If it is embedded in the data section, then it
461 * will be relocated with other data.
464 gd->fdt_size = ALIGN(fdt_totalsize(gd->fdt_blob) + 0x1000, 32);
466 gd->start_addr_sp -= gd->fdt_size;
467 gd->new_fdt = map_sysmem(gd->start_addr_sp, gd->fdt_size);
468 debug("Reserving %lu Bytes for FDT at: %08lx\n",
469 gd->fdt_size, gd->start_addr_sp);
476 static int reserve_bootstage(void)
478 #ifdef CONFIG_BOOTSTAGE
479 int size = bootstage_get_size();
481 gd->start_addr_sp -= size;
482 gd->new_bootstage = map_sysmem(gd->start_addr_sp, size);
483 debug("Reserving %#x Bytes for bootstage at: %08lx\n", size,
490 __weak int arch_reserve_stacks(void)
495 static int reserve_stacks(void)
497 /* make stack pointer 16-byte aligned */
498 gd->start_addr_sp -= 16;
499 gd->start_addr_sp &= ~0xf;
502 * let the architecture-specific code tailor gd->start_addr_sp and
505 return arch_reserve_stacks();
508 static int display_new_sp(void)
510 debug("New Stack Pointer is: %08lx\n", gd->start_addr_sp);
515 #if defined(CONFIG_M68K) || defined(CONFIG_MIPS) || defined(CONFIG_PPC) || \
517 static int setup_board_part1(void)
522 * Save local variables to board info struct
524 bd->bi_memstart = CONFIG_SYS_SDRAM_BASE; /* start of memory */
525 bd->bi_memsize = gd->ram_size; /* size in bytes */
527 #ifdef CONFIG_SYS_SRAM_BASE
528 bd->bi_sramstart = CONFIG_SYS_SRAM_BASE; /* start of SRAM */
529 bd->bi_sramsize = CONFIG_SYS_SRAM_SIZE; /* size of SRAM */
532 #if defined(CONFIG_E500) || defined(CONFIG_MPC86xx)
533 bd->bi_immr_base = CONFIG_SYS_IMMR; /* base of IMMR register */
535 #if defined(CONFIG_M68K)
536 bd->bi_mbar_base = CONFIG_SYS_MBAR; /* base of internal registers */
538 #if defined(CONFIG_MPC83xx)
539 bd->bi_immrbar = CONFIG_SYS_IMMR;
546 #if defined(CONFIG_PPC) || defined(CONFIG_M68K)
547 static int setup_board_part2(void)
551 bd->bi_intfreq = gd->cpu_clk; /* Internal Freq, in Hz */
552 bd->bi_busfreq = gd->bus_clk; /* Bus Freq, in Hz */
553 #if defined(CONFIG_CPM2)
554 bd->bi_cpmfreq = gd->arch.cpm_clk;
555 bd->bi_brgfreq = gd->arch.brg_clk;
556 bd->bi_sccfreq = gd->arch.scc_clk;
557 bd->bi_vco = gd->arch.vco_out;
558 #endif /* CONFIG_CPM2 */
559 #if defined(CONFIG_M68K) && defined(CONFIG_PCI)
560 bd->bi_pcifreq = gd->pci_clk;
562 #if defined(CONFIG_EXTRA_CLOCK)
563 bd->bi_inpfreq = gd->arch.inp_clk; /* input Freq in Hz */
564 bd->bi_vcofreq = gd->arch.vco_clk; /* vco Freq in Hz */
565 bd->bi_flbfreq = gd->arch.flb_clk; /* flexbus Freq in Hz */
573 static int init_post(void)
575 post_bootmode_init();
576 post_run(NULL, POST_ROM | post_bootmode_get(0));
582 static int reloc_fdt(void)
584 #ifndef CONFIG_OF_EMBED
585 if (gd->flags & GD_FLG_SKIP_RELOC)
588 memcpy(gd->new_fdt, gd->fdt_blob, gd->fdt_size);
589 gd->fdt_blob = gd->new_fdt;
596 static int reloc_bootstage(void)
598 #ifdef CONFIG_BOOTSTAGE
599 if (gd->flags & GD_FLG_SKIP_RELOC)
601 if (gd->new_bootstage) {
602 int size = bootstage_get_size();
604 debug("Copying bootstage from %p to %p, size %x\n",
605 gd->bootstage, gd->new_bootstage, size);
606 memcpy(gd->new_bootstage, gd->bootstage, size);
607 gd->bootstage = gd->new_bootstage;
614 static int setup_reloc(void)
616 if (gd->flags & GD_FLG_SKIP_RELOC) {
617 debug("Skipping relocation due to flag\n");
621 #ifdef CONFIG_SYS_TEXT_BASE
623 gd->reloc_off = gd->relocaddr - (unsigned long)__image_copy_start;
624 #elif defined(CONFIG_M68K)
626 * On all ColdFire arch cpu, monitor code starts always
627 * just after the default vector table location, so at 0x400
629 gd->reloc_off = gd->relocaddr - (CONFIG_SYS_TEXT_BASE + 0x400);
631 gd->reloc_off = gd->relocaddr - CONFIG_SYS_TEXT_BASE;
634 memcpy(gd->new_gd, (char *)gd, sizeof(gd_t));
636 debug("Relocation Offset is: %08lx\n", gd->reloc_off);
637 debug("Relocating to %08lx, new gd at %08lx, sp at %08lx\n",
638 gd->relocaddr, (ulong)map_to_sysmem(gd->new_gd),
644 #ifdef CONFIG_OF_BOARD_FIXUP
645 static int fix_fdt(void)
647 return board_fix_fdt((void *)gd->fdt_blob);
651 /* ARM calls relocate_code from its crt0.S */
652 #if !defined(CONFIG_ARM) && !defined(CONFIG_SANDBOX) && \
653 !CONFIG_IS_ENABLED(X86_64)
655 static int jump_to_copy(void)
657 if (gd->flags & GD_FLG_SKIP_RELOC)
660 * x86 is special, but in a nice way. It uses a trampoline which
661 * enables the dcache if possible.
663 * For now, other archs use relocate_code(), which is implemented
664 * similarly for all archs. When we do generic relocation, hopefully
665 * we can make all archs enable the dcache prior to relocation.
667 #if defined(CONFIG_X86) || defined(CONFIG_ARC)
669 * SDRAM and console are now initialised. The final stack can now
670 * be setup in SDRAM. Code execution will continue in Flash, but
671 * with the stack in SDRAM and Global Data in temporary memory
674 arch_setup_gd(gd->new_gd);
675 board_init_f_r_trampoline(gd->start_addr_sp);
677 relocate_code(gd->start_addr_sp, gd->new_gd, gd->relocaddr);
684 /* Record the board_init_f() bootstage (after arch_cpu_init()) */
685 static int initf_bootstage(void)
687 bool from_spl = IS_ENABLED(CONFIG_SPL_BOOTSTAGE) &&
688 IS_ENABLED(CONFIG_BOOTSTAGE_STASH);
691 ret = bootstage_init(!from_spl);
695 const void *stash = map_sysmem(CONFIG_BOOTSTAGE_STASH_ADDR,
696 CONFIG_BOOTSTAGE_STASH_SIZE);
698 ret = bootstage_unstash(stash, CONFIG_BOOTSTAGE_STASH_SIZE);
699 if (ret && ret != -ENOENT) {
700 debug("Failed to unstash bootstage: err=%d\n", ret);
705 bootstage_mark_name(BOOTSTAGE_ID_START_UBOOT_F, "board_init_f");
710 static int initf_console_record(void)
712 #if defined(CONFIG_CONSOLE_RECORD) && CONFIG_VAL(SYS_MALLOC_F_LEN)
713 return console_record_init();
719 static int initf_dm(void)
721 #if defined(CONFIG_DM) && CONFIG_VAL(SYS_MALLOC_F_LEN)
724 bootstage_start(BOOTSTATE_ID_ACCUM_DM_F, "dm_f");
725 ret = dm_init_and_scan(true);
726 bootstage_accum(BOOTSTATE_ID_ACCUM_DM_F);
730 #ifdef CONFIG_TIMER_EARLY
731 ret = dm_timer_init();
739 /* Architecture-specific memory reservation */
740 __weak int reserve_arch(void)
745 __weak int arch_cpu_init_dm(void)
750 static const init_fnc_t init_sequence_f[] = {
752 #ifdef CONFIG_OF_CONTROL
760 initf_bootstage, /* uses its own timer, so does not need DM */
761 initf_console_record,
762 #if defined(CONFIG_HAVE_FSP)
765 arch_cpu_init, /* basic arch cpu dependent setup */
766 mach_cpu_init, /* SoC/machine dependent CPU setup */
769 #if defined(CONFIG_BOARD_EARLY_INIT_F)
772 #if defined(CONFIG_PPC) || defined(CONFIG_SYS_FSL_CLK) || defined(CONFIG_M68K)
773 /* get CPU and bus clocks according to the environment variable */
774 get_clocks, /* get CPU and bus clocks (etc.) */
776 #if !defined(CONFIG_M68K)
777 timer_init, /* initialize timer */
779 #if defined(CONFIG_BOARD_POSTCLK_INIT)
782 env_init, /* initialize environment */
783 init_baud_rate, /* initialze baudrate settings */
784 serial_init, /* serial communications setup */
785 console_init_f, /* stage 1 init of console */
786 display_options, /* say that we are here */
787 display_text_info, /* show debugging info if required */
788 #if defined(CONFIG_PPC) || defined(CONFIG_SH) || defined(CONFIG_X86)
791 #if defined(CONFIG_DISPLAY_CPUINFO)
792 print_cpuinfo, /* display cpu info (and speed) */
794 #if defined(CONFIG_DTB_RESELECT)
797 #if defined(CONFIG_DISPLAY_BOARDINFO)
800 INIT_FUNC_WATCHDOG_INIT
801 #if defined(CONFIG_MISC_INIT_F)
804 INIT_FUNC_WATCHDOG_RESET
805 #if defined(CONFIG_SYS_I2C)
808 #if defined(CONFIG_VID) && !defined(CONFIG_SPL)
811 #if defined(CONFIG_HARD_SPI)
815 dram_init, /* configure available RAM banks */
819 INIT_FUNC_WATCHDOG_RESET
820 #if defined(CONFIG_SYS_DRAM_TEST)
822 #endif /* CONFIG_SYS_DRAM_TEST */
823 INIT_FUNC_WATCHDOG_RESET
828 INIT_FUNC_WATCHDOG_RESET
830 * Now that we have DRAM mapped and working, we can
831 * relocate the code and continue running from DRAM.
833 * Reserve memory at end of RAM for (top down in that order):
834 * - area that won't get touched by U-Boot and Linux (optional)
835 * - kernel log buffer
839 * - board info struct
862 #if defined(CONFIG_M68K) || defined(CONFIG_MIPS) || defined(CONFIG_PPC) || \
866 #if defined(CONFIG_PPC) || defined(CONFIG_M68K)
867 INIT_FUNC_WATCHDOG_RESET
871 #ifdef CONFIG_OF_BOARD_FIXUP
874 INIT_FUNC_WATCHDOG_RESET
878 #if defined(CONFIG_X86) || defined(CONFIG_ARC)
883 #if defined(CONFIG_XTENSA)
886 #if !defined(CONFIG_ARM) && !defined(CONFIG_SANDBOX) && \
887 !CONFIG_IS_ENABLED(X86_64)
893 void board_init_f(ulong boot_flags)
895 gd->flags = boot_flags;
896 gd->have_console = 0;
898 if (initcall_run_list(init_sequence_f))
901 #if !defined(CONFIG_ARM) && !defined(CONFIG_SANDBOX) && \
902 !defined(CONFIG_EFI_APP) && !CONFIG_IS_ENABLED(X86_64) && \
904 /* NOTREACHED - jump_to_copy() does not return */
909 #if defined(CONFIG_X86) || defined(CONFIG_ARC)
911 * For now this code is only used on x86.
913 * init_sequence_f_r is the list of init functions which are run when
914 * U-Boot is executing from Flash with a semi-limited 'C' environment.
915 * The following limitations must be considered when implementing an
917 * - 'static' variables are read-only
918 * - Global Data (gd->xxx) is read/write
920 * The '_f_r' sequence must, as a minimum, copy U-Boot to RAM (if
921 * supported). It _should_, if possible, copy global data to RAM and
922 * initialise the CPU caches (to speed up the relocation process)
924 * NOTE: At present only x86 uses this route, but it is intended that
925 * all archs will move to this when generic relocation is implemented.
927 static const init_fnc_t init_sequence_f_r[] = {
928 #if !CONFIG_IS_ENABLED(X86_64)
935 void board_init_f_r(void)
937 if (initcall_run_list(init_sequence_f_r))
941 * The pre-relocation drivers may be using memory that has now gone
942 * away. Mark serial as unavailable - this will fall back to the debug
945 * Do the same with log drivers since the memory may not be available.
947 gd->flags &= ~(GD_FLG_SERIAL_READY | GD_FLG_LOG_READY);
953 * U-Boot has been copied into SDRAM, the BSS has been cleared etc.
954 * Transfer execution from Flash to RAM by calculating the address
955 * of the in-RAM copy of board_init_r() and calling it
957 (board_init_r + gd->reloc_off)((gd_t *)gd, gd->relocaddr);
959 /* NOTREACHED - board_init_r() does not return */
962 #endif /* CONFIG_X86 */