u-boot/arch/arm/mach-imx/imx_bootaux.c
Igor Opaniuk c0f037f6a2 mach-imx: bootaux: elf firmware support
Currently imx-specific bootaux command doesn't support ELF format
firmware for Cortex-M4 core.

This patches introduces a PoC implementation of handling elf firmware
(load_elf_image_phdr() was copy-pasted from elf.c just for PoC).
ELF64 binaries isn't supported yet.

This has the advantage that the user does not need to know to which
address the binary has been linked to. However, in order to handle
and load the elf sections to the right address, we need to translate the
Cortex-M4 core memory addresses to primary/host CPU memory
addresses (Cortex A7/A9 cores).

This allows to boot firmwares from any location with just using
bootaux, e.g.:
> tftp ${loadaddr} hello_world.elf && bootaux ${loadaddr}

Similar translation table can be found in the Linux remoteproc
driver [1].

[1] https://elixir.bootlin.com/linux/latest/source/drivers/remoteproc/imx_rproc.c

Signed-off-by: Igor Opaniuk <igor.opaniuk@toradex.com>
Signed-off-by: Stefan Agner <stefan.agner@toradex.com>
Reviewed-by: Oleksandr Suvorov <oleksandr.suvorov@toradex.com>
2020-01-07 10:26:56 +01:00

189 lines
4.2 KiB
C

// SPDX-License-Identifier: GPL-2.0+
/*
* Copyright (C) 2016 Freescale Semiconductor, Inc.
*/
#include <common.h>
#include <asm/io.h>
#include <asm/mach-imx/sys_proto.h>
#include <command.h>
#include <elf.h>
#include <imx_sip.h>
#include <linux/compiler.h>
#include <cpu_func.h>
#ifndef CONFIG_IMX8M
const __weak struct rproc_att hostmap[] = { };
static const struct rproc_att *get_host_mapping(unsigned long auxcore)
{
const struct rproc_att *mmap = hostmap;
while (mmap && mmap->size) {
if (mmap->da <= auxcore &&
mmap->da + mmap->size > auxcore)
return mmap;
mmap++;
}
return NULL;
}
/*
* A very simple elf loader, assumes the image is valid, returns the
* entry point address.
*/
static unsigned long load_elf_image_phdr(unsigned long addr)
{
Elf32_Ehdr *ehdr; /* ELF header structure pointer */
Elf32_Phdr *phdr; /* Program header structure pointer */
int i;
ehdr = (Elf32_Ehdr *)addr;
phdr = (Elf32_Phdr *)(addr + ehdr->e_phoff);
/* Load each program header */
for (i = 0; i < ehdr->e_phnum; ++i, ++phdr) {
const struct rproc_att *mmap = get_host_mapping(phdr->p_paddr);
void *dst, *src;
if (phdr->p_type != PT_LOAD)
continue;
if (!mmap) {
printf("Invalid aux core address: %08x",
phdr->p_paddr);
return 0;
}
dst = (void *)(phdr->p_paddr - mmap->da) + mmap->sa;
src = (void *)addr + phdr->p_offset;
debug("Loading phdr %i to 0x%p (%i bytes)\n",
i, dst, phdr->p_filesz);
if (phdr->p_filesz)
memcpy(dst, src, phdr->p_filesz);
if (phdr->p_filesz != phdr->p_memsz)
memset(dst + phdr->p_filesz, 0x00,
phdr->p_memsz - phdr->p_filesz);
flush_cache((unsigned long)dst &
~(CONFIG_SYS_CACHELINE_SIZE - 1),
ALIGN(phdr->p_filesz, CONFIG_SYS_CACHELINE_SIZE));
}
return ehdr->e_entry;
}
#endif
int arch_auxiliary_core_up(u32 core_id, ulong addr)
{
ulong stack, pc;
if (!addr)
return -EINVAL;
#ifdef CONFIG_IMX8M
stack = *(u32 *)addr;
pc = *(u32 *)(addr + 4);
#else
/*
* handling ELF64 binaries
* isn't supported yet.
*/
if (valid_elf_image(addr)) {
stack = 0x0;
pc = load_elf_image_phdr(addr);
if (!pc)
return CMD_RET_FAILURE;
} else {
/*
* Assume binary file with vector table at the beginning.
* Cortex-M4 vector tables start with the stack pointer (SP)
* and reset vector (initial PC).
*/
stack = *(u32 *)addr;
pc = *(u32 *)(addr + 4);
}
#endif
printf("## Starting auxiliary core stack = 0x%08lX, pc = 0x%08lX...\n",
stack, pc);
/* Set the stack and pc to M4 bootROM */
writel(stack, M4_BOOTROM_BASE_ADDR);
writel(pc, M4_BOOTROM_BASE_ADDR + 4);
flush_dcache_all();
/* Enable M4 */
#ifdef CONFIG_IMX8M
call_imx_sip(IMX_SIP_SRC, IMX_SIP_SRC_M4_START, 0, 0, 0);
#else
clrsetbits_le32(SRC_BASE_ADDR + SRC_M4_REG_OFFSET,
SRC_M4C_NON_SCLR_RST_MASK, SRC_M4_ENABLE_MASK);
#endif
return 0;
}
int arch_auxiliary_core_check_up(u32 core_id)
{
#ifdef CONFIG_IMX8M
return call_imx_sip(IMX_SIP_SRC, IMX_SIP_SRC_M4_STARTED, 0, 0, 0);
#else
unsigned int val;
val = readl(SRC_BASE_ADDR + SRC_M4_REG_OFFSET);
if (val & SRC_M4C_NON_SCLR_RST_MASK)
return 0; /* assert in reset */
return 1;
#endif
}
/*
* To i.MX6SX and i.MX7D, the image supported by bootaux needs
* the reset vector at the head for the image, with SP and PC
* as the first two words.
*
* Per the cortex-M reference manual, the reset vector of M4 needs
* to exist at 0x0 (TCMUL). The PC and SP are the first two addresses
* of that vector. So to boot M4, the A core must build the M4's reset
* vector with getting the PC and SP from image and filling them to
* TCMUL. When M4 is kicked, it will load the PC and SP by itself.
* The TCMUL is mapped to (M4_BOOTROM_BASE_ADDR) at A core side for
* accessing the M4 TCMUL.
*/
static int do_bootaux(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
{
ulong addr;
int ret, up;
if (argc < 2)
return CMD_RET_USAGE;
up = arch_auxiliary_core_check_up(0);
if (up) {
printf("## Auxiliary core is already up\n");
return CMD_RET_SUCCESS;
}
addr = simple_strtoul(argv[1], NULL, 16);
if (!addr)
return CMD_RET_FAILURE;
ret = arch_auxiliary_core_up(0, addr);
if (ret)
return CMD_RET_FAILURE;
return CMD_RET_SUCCESS;
}
U_BOOT_CMD(
bootaux, CONFIG_SYS_MAXARGS, 1, do_bootaux,
"Start auxiliary core",
""
);