xref: /openbmc/u-boot/post/lib_powerpc/b.c (revision 1d2c0506)
1 /*
2  * (C) Copyright 2002
3  * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
4  *
5  * SPDX-License-Identifier:	GPL-2.0+
6  */
7 
8 #include <common.h>
9 
10 /*
11  * CPU test
12  * Branch instructions:		b, bl, bc
13  *
14  * The first 2 instructions (b, bl) are verified by jumping
15  * to a fixed address and checking whether control was transferred
16  * to that very point. For the bl instruction the value of the
17  * link register is checked as well (using mfspr).
18  * To verify the bc instruction various combinations of the BI/BO
19  * fields, the CTR and the condition register values are
20  * checked. The list of such combinations is pre-built and
21  * linked in U-Boot at build time.
22  */
23 
24 #include <post.h>
25 #include "cpu_asm.h"
26 
27 #if CONFIG_POST & CONFIG_SYS_POST_CPU
28 
29 extern void cpu_post_exec_11 (ulong *code, ulong *res, ulong op1);
30 extern void cpu_post_exec_31 (ulong *code, ulong *ctr, ulong *lr, ulong *jump,
31     ulong cr);
32 
33 static int cpu_post_test_bc (ulong cmd, ulong bo, ulong bi,
34     int pjump, int decr, int link, ulong pctr, ulong cr)
35 {
36     int ret = 0;
37     ulong lr = 0;
38     ulong ctr = pctr;
39     ulong jump;
40 
41     unsigned long code[] =
42     {
43 	ASM_MTCR(6),
44 	ASM_MFLR(6),
45 	ASM_MTCTR(3),
46 	ASM_MTLR(4),
47 	ASM_LI(5, 1),
48 	ASM_3O(cmd, bo, bi, 8),
49 	ASM_LI(5, 0),
50 	ASM_MFCTR(3),
51 	ASM_MFLR(4),
52 	ASM_MTLR(6),
53 	ASM_BLR,
54     };
55 
56     cpu_post_exec_31 (code, &ctr, &lr, &jump, cr);
57 
58     if (ret == 0)
59 	ret = pjump == jump ? 0 : -1;
60     if (ret == 0)
61     {
62 	if (decr)
63 	    ret = pctr == ctr + 1 ? 0 : -1;
64 	else
65 	    ret = pctr == ctr ? 0 : -1;
66     }
67     if (ret == 0)
68     {
69 	if (link)
70 	    ret = lr == (ulong) code + 24 ? 0 : -1;
71 	else
72 	    ret = lr == 0 ? 0 : -1;
73     }
74 
75     return ret;
76 }
77 
78 int cpu_post_test_b (void)
79 {
80     int ret = 0;
81     unsigned int i;
82     int flag = disable_interrupts();
83 
84     if (ret == 0)
85     {
86 	ulong code[] =
87 	{
88 	   ASM_MFLR(4),
89 	   ASM_MTLR(3),
90 	   ASM_B(4),
91 	   ASM_MFLR(3),
92 	   ASM_MTLR(4),
93 	   ASM_BLR,
94 	};
95 	ulong res;
96 
97 	cpu_post_exec_11 (code, &res, 0);
98 
99 	ret = res == 0 ? 0 : -1;
100 
101 	if (ret != 0)
102 	{
103 	    post_log ("Error at b1 test !\n");
104 	}
105     }
106 
107     if (ret == 0)
108     {
109 	ulong code[] =
110 	{
111 	   ASM_MFLR(4),
112 	   ASM_MTLR(3),
113 	   ASM_BL(4),
114 	   ASM_MFLR(3),
115 	   ASM_MTLR(4),
116 	   ASM_BLR,
117 	};
118 	ulong res;
119 
120 	cpu_post_exec_11 (code, &res, 0);
121 
122 	ret = res == (ulong)code + 12 ? 0 : -1;
123 
124 	if (ret != 0)
125 	{
126 	    post_log ("Error at b2 test !\n");
127 	}
128     }
129 
130     if (ret == 0)
131     {
132 	ulong cc, cd;
133 	int cond;
134 	ulong ctr;
135 	int link;
136 
137 	i = 0;
138 
139 	for (cc = 0; cc < 4 && ret == 0; cc++)
140 	{
141 	    for (cd = 0; cd < 4 && ret == 0; cd++)
142 	    {
143 		for (link = 0; link <= 1 && ret == 0; link++)
144 		{
145 		    for (cond = 0; cond <= 1 && ret == 0; cond++)
146 		    {
147 			for (ctr = 1; ctr <= 2 && ret == 0; ctr++)
148 			{
149 			    int decr = cd < 2;
150 			    int cr = cond ? 0x80000000 : 0x00000000;
151 			    int jumpc = cc >= 2 ||
152 					(cc == 0 && !cond) ||
153 					(cc == 1 && cond);
154 			    int jumpd = cd >= 2 ||
155 					(cd == 0 && ctr != 1) ||
156 					(cd == 1 && ctr == 1);
157 			    int jump = jumpc && jumpd;
158 
159 			    ret = cpu_post_test_bc (link ? OP_BCL : OP_BC,
160 				(cc << 3) + (cd << 1), 0, jump, decr, link,
161 				ctr, cr);
162 
163 			    if (ret != 0)
164 			    {
165 				post_log ("Error at b3 test %d !\n", i);
166 			    }
167 
168 			    i++;
169 			}
170 		    }
171 		}
172 	    }
173 	}
174     }
175 
176     if (flag)
177 	enable_interrupts();
178 
179     return ret;
180 }
181 
182 #endif
183