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author | Dzmitry Sankouski <dsankouski@gmail.com> | 2022-02-22 21:49:52 +0300 |
---|---|---|
committer | Tom Rini <trini@konsulko.com> | 2022-04-04 14:53:26 -0400 |
commit | 12a3e1ada06c702c403cf1eebb063ef7a34688cd (patch) | |
tree | d58972054d39b90b0b0a92d5c9b093d0547264a6 /arch | |
parent | 5c9b420ada3b4f2a08da4789571f0ea373881565 (diff) | |
download | u-boot-12a3e1ada06c702c403cf1eebb063ef7a34688cd.zip u-boot-12a3e1ada06c702c403cf1eebb063ef7a34688cd.tar.gz u-boot-12a3e1ada06c702c403cf1eebb063ef7a34688cd.tar.bz2 |
arm: init: save previous bootloader data
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>
Diffstat (limited to 'arch')
-rw-r--r-- | arch/arm/lib/Makefile | 5 | ||||
-rw-r--r-- | arch/arm/lib/save_prev_bl_data.c | 91 |
2 files changed, 96 insertions, 0 deletions
diff --git a/arch/arm/lib/Makefile b/arch/arm/lib/Makefile index 594fc12..c603fe6 100644 --- a/arch/arm/lib/Makefile +++ b/arch/arm/lib/Makefile @@ -48,6 +48,11 @@ obj-$(CONFIG_$(SPL_TPL_)USE_ARCH_MEMCPY) += memcpy.o endif obj-$(CONFIG_$(SPL_TPL_)SEMIHOSTING) += semihosting.o +ifneq ($(filter y,$(CONFIG_SAVE_PREV_BL_INITRAMFS_START_ADDR) $(CONFIG_SAVE_PREV_BL_FDT_ADDR)),) +obj-y += save_prev_bl_data.o +endif + +# obj-$(CONFIG_SAVE_PREV_BL_INITRAMFS_START_ADDR) += save_prev_bl_data.o obj-y += bdinfo.o obj-y += sections.o CFLAGS_REMOVE_sections.o := $(LTO_CFLAGS) diff --git a/arch/arm/lib/save_prev_bl_data.c b/arch/arm/lib/save_prev_bl_data.c new file mode 100644 index 0000000..f4ee86a --- /dev/null +++ b/arch/arm/lib/save_prev_bl_data.c @@ -0,0 +1,91 @@ +// 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; +} |