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imx_bootaux.c 1.92 KiB
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  • /*
     * Copyright (C) 2016 Freescale Semiconductor, Inc.
     *
     * SPDX-License-Identifier:	GPL-2.0+
     */
    
    #include <common.h>
    #include <command.h>
    
    /* Allow for arch specific config before we boot */
    static int __arch_auxiliary_core_up(u32 core_id, u32 boot_private_data)
    {
    	/* please define platform specific arch_auxiliary_core_up() */
    	return CMD_RET_FAILURE;
    }
    
    int arch_auxiliary_core_up(u32 core_id, u32 boot_private_data)
    	__attribute__((weak, alias("__arch_auxiliary_core_up")));
    
    /* Allow for arch specific config before we boot */
    static int __arch_auxiliary_core_check_up(u32 core_id)
    {
    	/* please define platform specific arch_auxiliary_core_check_up() */
    	return 0;
    }
    
    int arch_auxiliary_core_check_up(u32 core_id)
    	__attribute__((weak, alias("__arch_auxiliary_core_check_up")));
    
    /*
     * 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.
     */
    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",
    	""
    );