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
15static 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
45static 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
80static int segments_open(struct inode *inode, struct file *file)
81{
82	return single_open(file, show_segments, NULL);
83}
84
85static const struct file_operations segments_fops = {
86	.open		= segments_open,
87	.read		= seq_read,
88	.llseek		= seq_lseek,
89	.release	= single_release,
90};
91
92static 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
110device_initcall(segments_info);
111