mirror of
https://github.com/AsahiLinux/u-boot
synced 2024-11-15 09:27:35 +00:00
12a3e1ada0
When u-boot is used as a chain-loaded bootloader (replacing OS kernel), previous bootloader leaves data in RAM, that can be reused. For example, on recent arm linux system, when chainloading u-boot, there are initramfs and fdt in RAM prepared for OS booting. Initramfs may be modified to store u-boot's payload, thus providing the ability to use chainloaded u-boot to boot OS without any storage support. Two config options added: - SAVE_PREV_BL_INITRAMFS_START_ADDR saves initramfs start address to 'prevbl_initrd_start_addr' environment variable - SAVE_PREV_BL_FDT_ADDR saves fdt address to 'prevbl_fdt_addr' environment variable Signed-off-by: Dzmitry Sankouski <dsankouski@gmail.com> Cc: Tom Rini <trini@konsulko.com>
91 lines
2.2 KiB
C
91 lines
2.2 KiB
C
// SPDX-License-Identifier: GPL-2.0+
|
|
/*
|
|
* save_prev_bl_data - saving previous bootloader data
|
|
* to environment variables.
|
|
*
|
|
* Copyright (c) 2022 Dzmitry Sankouski (dsankouski@gmail.com)
|
|
*/
|
|
#include <init.h>
|
|
#include <env.h>
|
|
#include <fdtdec.h>
|
|
#include <fdt_support.h>
|
|
#include <fdt.h>
|
|
#include <common.h>
|
|
#include <linux/errno.h>
|
|
#include <asm/system.h>
|
|
#include <asm/armv8/mmu.h>
|
|
|
|
static ulong reg0 __section(".data");
|
|
|
|
/**
|
|
* Save x0 register value, assuming previous bootloader set it to
|
|
* point on loaded fdt or (for older linux kernels)atags.
|
|
*/
|
|
void save_boot_params(ulong r0)
|
|
{
|
|
reg0 = r0;
|
|
save_boot_params_ret();
|
|
}
|
|
|
|
bool is_addr_accessible(phys_addr_t addr)
|
|
{
|
|
struct mm_region *mem = mem_map;
|
|
phys_addr_t bank_start;
|
|
phys_addr_t bank_end;
|
|
|
|
while (mem->size) {
|
|
bank_start = mem->phys;
|
|
bank_end = bank_start + mem->size;
|
|
debug("check if block %pap - %pap includes %pap\n", &bank_start, &bank_end, &addr);
|
|
if (addr > bank_start && addr < bank_end)
|
|
return true;
|
|
mem++;
|
|
}
|
|
|
|
return false;
|
|
}
|
|
|
|
int save_prev_bl_data(void)
|
|
{
|
|
struct fdt_header *fdt_blob;
|
|
int node;
|
|
u64 initrd_start_prop;
|
|
|
|
if (!is_addr_accessible((phys_addr_t)reg0))
|
|
return -ENODATA;
|
|
|
|
fdt_blob = (struct fdt_header *)reg0;
|
|
if (!fdt_valid(&fdt_blob)) {
|
|
pr_warn("%s: address 0x%lx is not a valid fdt\n", __func__, reg0);
|
|
return -ENODATA;
|
|
}
|
|
|
|
if (CONFIG_IS_ENABLED(SAVE_PREV_BL_FDT_ADDR))
|
|
env_set_addr("prevbl_fdt_addr", (void *)reg0);
|
|
if (!CONFIG_IS_ENABLED(SAVE_PREV_BL_INITRAMFS_START_ADDR))
|
|
return 0;
|
|
|
|
node = fdt_path_offset(fdt_blob, "/chosen");
|
|
if (!node) {
|
|
pr_warn("%s: chosen node not found in device tree at addr: 0x%lx\n",
|
|
__func__, reg0);
|
|
return -ENODATA;
|
|
}
|
|
/*
|
|
* linux,initrd-start property might be either 64 or 32 bit,
|
|
* depending on primary bootloader implementation.
|
|
*/
|
|
initrd_start_prop = fdtdec_get_uint64(fdt_blob, node, "linux,initrd-start", 0);
|
|
if (!initrd_start_prop) {
|
|
debug("%s: attempt to get uint64 linux,initrd-start property failed, trying uint\n",
|
|
__func__);
|
|
initrd_start_prop = fdtdec_get_uint(fdt_blob, node, "linux,initrd-start", 0);
|
|
if (!initrd_start_prop) {
|
|
debug("%s: attempt to get uint failed, too\n", __func__);
|
|
return -ENODATA;
|
|
}
|
|
}
|
|
env_set_addr("prevbl_initrd_start_addr", (void *)initrd_start_prop);
|
|
|
|
return 0;
|
|
}
|