xref: /openbmc/u-boot/arch/x86/lib/fsp/fsp_car.S (revision 29b103c7)
1/*
2 * Copyright (C) 2014, Bin Meng <bmeng.cn@gmail.com>
3 *
4 * SPDX-License-Identifier:	GPL-2.0+
5 */
6
7#include <config.h>
8#include <asm/post.h>
9
10.globl car_init
11car_init:
12	/*
13	 * Note: ebp holds the BIST value (built-in self test) so far, but ebp
14	 * will be destroyed through the FSP call, thus we have to test the
15	 * BIST value here before we call into FSP.
16	 */
17	test	%ebp, %ebp
18	jz	car_init_start
19	post_code(POST_BIST_FAILURE)
20	jmp	die
21
22car_init_start:
23	post_code(POST_CAR_START)
24	lea	find_fsp_header_romstack, %esp
25	jmp	find_fsp_header
26
27find_fsp_header_ret:
28	/* EAX points to FSP_INFO_HEADER */
29	mov	%eax, %ebp
30
31	/* sanity test */
32	cmp	$CONFIG_FSP_ADDR, %eax
33	jb	die
34
35	/* calculate TempRamInitEntry address */
36	mov	0x30(%ebp), %eax
37	add	0x1c(%ebp), %eax
38
39	/* call FSP TempRamInitEntry to setup temporary stack */
40	lea	temp_ram_init_romstack, %esp
41	jmp	*%eax
42
43temp_ram_init_ret:
44	addl	$4, %esp
45	cmp	$0, %eax
46	jnz	car_init_fail
47
48	post_code(POST_CAR_CPU_CACHE)
49
50	/*
51	 * The FSP TempRamInit initializes the ecx and edx registers to
52	 * point to a temporary but writable memory range (Cache-As-RAM).
53	 * ecx: the start of this temporary memory range,
54	 * edx: the end of this range.
55	 */
56
57	/* stack grows down from top of CAR */
58	movl	%edx, %esp
59	subl	$4, %esp
60
61	xor	%esi, %esi
62	jmp	car_init_done
63
64.global fsp_init_done
65fsp_init_done:
66	/*
67	 * We come here from FspInit with eax pointing to the HOB list.
68	 * Save eax to esi temporarily.
69	 */
70	movl	%eax, %esi
71
72car_init_done:
73	/*
74	 * Re-initialize the ebp (BIST) to zero, as we already reach here
75	 * which means we passed BIST testing before.
76	 */
77	xorl	%ebp, %ebp
78	jmp	car_init_ret
79
80car_init_fail:
81	post_code(POST_CAR_FAILURE)
82
83die:
84	hlt
85	jmp	die
86	hlt
87
88	/*
89	 * The function call before CAR initialization is tricky. It cannot
90	 * be called using the 'call' instruction but only the 'jmp' with
91	 * the help of a handcrafted stack in the ROM. The stack needs to
92	 * contain the function return address as well as the parameters.
93	 */
94	.balign	4
95find_fsp_header_romstack:
96	.long	find_fsp_header_ret
97
98	.balign	4
99temp_ram_init_romstack:
100	.long	temp_ram_init_ret
101	.long	temp_ram_init_params
102temp_ram_init_params:
103_dt_ucode_base_size:
104	/* These next two fields are filled in by ifdtool */
105	.long	0			/* microcode base */
106	.long	0			/* microcode size */
107	.long	CONFIG_SYS_MONITOR_BASE	/* code region base */
108	.long	CONFIG_SYS_MONITOR_LEN	/* code region size */
109