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Add a mechanism for early SoC initialization for platforms that need
additional hardware initialization not possible through the regular
device tree and drivers mechanism. With this, a SoC specific
initialization function can be called very early, before DTB parsing
is done by parse_dtb() in Linux RISC-V kernel setup code.
This can be very useful for early hardware initialization for No-MMU
kernels booted directly in M-mode because it is quite likely that no
other booting stage exist prior to the No-MMU kernel.
Example use of a SoC early initialization is as follows:
static void vendor_abc_early_init(const void *fdt)
{
/*
* some early init code here that can use simple matches
* against the flat device tree file.
*/
}
SOC_EARLY_INIT_DECLARE("vendor,abc", abc_early_init);
This early initialization function is executed only if the flat device
tree for the board has a 'compatible = "vendor,abc"' entry;
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: Anup Patel <anup.patel@wdc.com>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
98 lines
1.5 KiB
ArmAsm
98 lines
1.5 KiB
ArmAsm
/* SPDX-License-Identifier: GPL-2.0-only */
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/*
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* Copyright (C) 2012 Regents of the University of California
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* Copyright (C) 2017 SiFive
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*/
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#define LOAD_OFFSET PAGE_OFFSET
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#include <asm/vmlinux.lds.h>
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#include <asm/page.h>
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#include <asm/cache.h>
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#include <asm/thread_info.h>
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#include <asm/set_memory.h>
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#include <linux/sizes.h>
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OUTPUT_ARCH(riscv)
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ENTRY(_start)
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jiffies = jiffies_64;
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SECTIONS
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{
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/* Beginning of code and text segment */
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. = LOAD_OFFSET;
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_start = .;
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HEAD_TEXT_SECTION
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. = ALIGN(PAGE_SIZE);
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__init_begin = .;
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INIT_TEXT_SECTION(PAGE_SIZE)
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INIT_DATA_SECTION(16)
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. = ALIGN(8);
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__soc_early_init_table : {
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__soc_early_init_table_start = .;
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KEEP(*(__soc_early_init_table))
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__soc_early_init_table_end = .;
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}
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/* we have to discard exit text and such at runtime, not link time */
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.exit.text :
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{
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EXIT_TEXT
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}
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.exit.data :
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{
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EXIT_DATA
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}
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PERCPU_SECTION(L1_CACHE_BYTES)
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__init_end = .;
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. = ALIGN(SECTION_ALIGN);
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.text : {
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_text = .;
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_stext = .;
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TEXT_TEXT
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SCHED_TEXT
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CPUIDLE_TEXT
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LOCK_TEXT
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KPROBES_TEXT
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ENTRY_TEXT
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IRQENTRY_TEXT
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SOFTIRQENTRY_TEXT
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*(.fixup)
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_etext = .;
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}
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/* Start of data section */
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_sdata = .;
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RO_DATA(SECTION_ALIGN)
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.srodata : {
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*(.srodata*)
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}
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EXCEPTION_TABLE(0x10)
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. = ALIGN(SECTION_ALIGN);
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_data = .;
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RW_DATA(L1_CACHE_BYTES, PAGE_SIZE, THREAD_SIZE)
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.sdata : {
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__global_pointer$ = . + 0x800;
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*(.sdata*)
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/* End of data section */
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_edata = .;
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}
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BSS_SECTION(PAGE_SIZE, PAGE_SIZE, 0)
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.rel.dyn : {
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*(.rel.dyn*)
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}
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_end = .;
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STABS_DEBUG
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DWARF_DEBUG
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DISCARDS
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}
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