1 /*
2 * This file is subject to the terms and conditions of the GNU General Public
3 * License. See the file "COPYING" in the main directory of this archive
4 * for more details.
5 *
6 * Copyright (C) 2013 Imagination Technologies Ltd.
7 */
8
9 #include <linux/kernel.h>
10 #include <linux/debugfs.h>
11 #include <linux/seq_file.h>
12 #include <asm/cpu.h>
13 #include <asm/mipsregs.h>
14
build_segment_config(char * str,unsigned int cfg)15 static void build_segment_config(char *str, unsigned int cfg)
16 {
17 unsigned int am;
18 static const char * const am_str[] = {
19 "UK", "MK", "MSK", "MUSK", "MUSUK", "USK",
20 "RSRVD", "UUSK"};
21
22 /* Segment access mode. */
23 am = (cfg & MIPS_SEGCFG_AM) >> MIPS_SEGCFG_AM_SHIFT;
24 str += sprintf(str, "%-5s", am_str[am]);
25
26 /*
27 * Access modes MK, MSK and MUSK are mapped segments. Therefore
28 * there is no direct physical address mapping.
29 */
30 if ((am == 0) || (am > 3)) {
31 str += sprintf(str, " %03lx",
32 ((cfg & MIPS_SEGCFG_PA) >> MIPS_SEGCFG_PA_SHIFT));
33 str += sprintf(str, " %01ld",
34 ((cfg & MIPS_SEGCFG_C) >> MIPS_SEGCFG_C_SHIFT));
35 } else {
36 str += sprintf(str, " UND");
37 str += sprintf(str, " U");
38 }
39
40 /* Exception configuration. */
41 str += sprintf(str, " %01ld\n",
42 ((cfg & MIPS_SEGCFG_EU) >> MIPS_SEGCFG_EU_SHIFT));
43 }
44
show_segments(struct seq_file * m,void * v)45 static int show_segments(struct seq_file *m, void *v)
46 {
47 unsigned int segcfg;
48 char str[42];
49
50 seq_puts(m, "Segment Virtual Size Access Mode Physical Caching EU\n");
51 seq_puts(m, "------- ------- ---- ----------- -------- ------- --\n");
52
53 segcfg = read_c0_segctl0();
54 build_segment_config(str, segcfg);
55 seq_printf(m, " 0 e0000000 512M %s", str);
56
57 segcfg >>= 16;
58 build_segment_config(str, segcfg);
59 seq_printf(m, " 1 c0000000 512M %s", str);
60
61 segcfg = read_c0_segctl1();
62 build_segment_config(str, segcfg);
63 seq_printf(m, " 2 a0000000 512M %s", str);
64
65 segcfg >>= 16;
66 build_segment_config(str, segcfg);
67 seq_printf(m, " 3 80000000 512M %s", str);
68
69 segcfg = read_c0_segctl2();
70 build_segment_config(str, segcfg);
71 seq_printf(m, " 4 40000000 1G %s", str);
72
73 segcfg >>= 16;
74 build_segment_config(str, segcfg);
75 seq_printf(m, " 5 00000000 1G %s\n", str);
76
77 return 0;
78 }
79
segments_open(struct inode * inode,struct file * file)80 static int segments_open(struct inode *inode, struct file *file)
81 {
82 return single_open(file, show_segments, NULL);
83 }
84
85 static const struct file_operations segments_fops = {
86 .open = segments_open,
87 .read = seq_read,
88 .llseek = seq_lseek,
89 .release = single_release,
90 };
91
segments_info(void)92 static int __init segments_info(void)
93 {
94 extern struct dentry *mips_debugfs_dir;
95 struct dentry *segments;
96
97 if (cpu_has_segments) {
98 if (!mips_debugfs_dir)
99 return -ENODEV;
100
101 segments = debugfs_create_file("segments", S_IRUGO,
102 mips_debugfs_dir, NULL,
103 &segments_fops);
104 if (!segments)
105 return -ENOMEM;
106 }
107 return 0;
108 }
109
110 device_initcall(segments_info);
111