u-boot/arch/arm/mach-imx/imx_bootaux.c

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// 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 <imx_sip.h>
#include <linux/compiler.h>
int arch_auxiliary_core_up(u32 core_id, ulong boot_private_data)
{
ulong stack, pc;
if (!boot_private_data)
return -EINVAL;
stack = *(ulong *)boot_private_data;
pc = *(ulong *)(boot_private_data + 4);
/* Set the stack and pc to M4 bootROM */
writel(stack, M4_BOOTROM_BASE_ADDR);
writel(pc, M4_BOOTROM_BASE_ADDR + 4);
/* Enable M4 */
#ifdef CONFIG_MX8M
call_imx_sip(IMX_SIP_SRC, IMX_SIP_SRC_M4_START, 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_MX8M
return call_imx_sip(IMX_SIP_SRC, IMX_SIP_SRC_M4_STARTED, 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);
printf("## Starting auxiliary core at 0x%08lX ...\n", addr);
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",
""
);