xref: /openbmc/u-boot/arch/arm/mach-imx/imx_bootaux.c (revision baefb63a)
1 /*
2  * Copyright (C) 2016 Freescale Semiconductor, Inc.
3  *
4  * SPDX-License-Identifier:	GPL-2.0+
5  */
6 
7 #include <common.h>
8 #include <command.h>
9 
10 /* Allow for arch specific config before we boot */
11 static int __arch_auxiliary_core_up(u32 core_id, u32 boot_private_data)
12 {
13 	/* please define platform specific arch_auxiliary_core_up() */
14 	return CMD_RET_FAILURE;
15 }
16 
17 int arch_auxiliary_core_up(u32 core_id, u32 boot_private_data)
18 	__attribute__((weak, alias("__arch_auxiliary_core_up")));
19 
20 /* Allow for arch specific config before we boot */
21 static int __arch_auxiliary_core_check_up(u32 core_id)
22 {
23 	/* please define platform specific arch_auxiliary_core_check_up() */
24 	return 0;
25 }
26 
27 int arch_auxiliary_core_check_up(u32 core_id)
28 	__attribute__((weak, alias("__arch_auxiliary_core_check_up")));
29 
30 /*
31  * To i.MX6SX and i.MX7D, the image supported by bootaux needs
32  * the reset vector at the head for the image, with SP and PC
33  * as the first two words.
34  *
35  * Per the cortex-M reference manual, the reset vector of M4 needs
36  * to exist at 0x0 (TCMUL). The PC and SP are the first two addresses
37  * of that vector.  So to boot M4, the A core must build the M4's reset
38  * vector with getting the PC and SP from image and filling them to
39  * TCMUL. When M4 is kicked, it will load the PC and SP by itself.
40  * The TCMUL is mapped to (M4_BOOTROM_BASE_ADDR) at A core side for
41  * accessing the M4 TCMUL.
42  */
43 int do_bootaux(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
44 {
45 	ulong addr;
46 	int ret, up;
47 
48 	if (argc < 2)
49 		return CMD_RET_USAGE;
50 
51 	up = arch_auxiliary_core_check_up(0);
52 	if (up) {
53 		printf("## Auxiliary core is already up\n");
54 		return CMD_RET_SUCCESS;
55 	}
56 
57 	addr = simple_strtoul(argv[1], NULL, 16);
58 
59 	printf("## Starting auxiliary core at 0x%08lX ...\n", addr);
60 
61 	ret = arch_auxiliary_core_up(0, addr);
62 	if (ret)
63 		return CMD_RET_FAILURE;
64 
65 	return CMD_RET_SUCCESS;
66 }
67 
68 U_BOOT_CMD(
69 	bootaux, CONFIG_SYS_MAXARGS, 1,	do_bootaux,
70 	"Start auxiliary core",
71 	""
72 );
73