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/debug.h>
14#include <asm/mipsregs.h>
15
16static void build_segment_config(char *str, unsigned int cfg)
17{
18	unsigned int am;
19	static const char * const am_str[] = {
20		"UK", "MK", "MSK", "MUSK", "MUSUK", "USK",
21		"RSRVD", "UUSK"};
22
23	/* Segment access mode. */
24	am = (cfg & MIPS_SEGCFG_AM) >> MIPS_SEGCFG_AM_SHIFT;
25	str += sprintf(str, "%-5s", am_str[am]);
26
27	/*
28	 * Access modes MK, MSK and MUSK are mapped segments. Therefore
29	 * there is no direct physical address mapping.
30	 */
31	if ((am == 0) || (am > 3)) {
32		str += sprintf(str, "         %03lx",
33			((cfg & MIPS_SEGCFG_PA) >> MIPS_SEGCFG_PA_SHIFT));
34		str += sprintf(str, "         %01ld",
35			((cfg & MIPS_SEGCFG_C) >> MIPS_SEGCFG_C_SHIFT));
36	} else {
37		str += sprintf(str, "         UND");
38		str += sprintf(str, "         U");
39	}
40
41	/* Exception configuration. */
42	str += sprintf(str, "       %01ld\n",
43		((cfg & MIPS_SEGCFG_EU) >> MIPS_SEGCFG_EU_SHIFT));
44}
45
46static int show_segments(struct seq_file *m, void *v)
47{
48	unsigned int segcfg;
49	char str[42];
50
51	seq_puts(m, "Segment   Virtual    Size   Access Mode   Physical   Caching   EU\n");
52	seq_puts(m, "-------   -------    ----   -----------   --------   -------   --\n");
53
54	segcfg = read_c0_segctl0();
55	build_segment_config(str, segcfg);
56	seq_printf(m, "   0      e0000000   512M      %s", str);
57
58	segcfg >>= 16;
59	build_segment_config(str, segcfg);
60	seq_printf(m, "   1      c0000000   512M      %s", str);
61
62	segcfg = read_c0_segctl1();
63	build_segment_config(str, segcfg);
64	seq_printf(m, "   2      a0000000   512M      %s", str);
65
66	segcfg >>= 16;
67	build_segment_config(str, segcfg);
68	seq_printf(m, "   3      80000000   512M      %s", str);
69
70	segcfg = read_c0_segctl2();
71	build_segment_config(str, segcfg);
72	seq_printf(m, "   4      40000000    1G       %s", str);
73
74	segcfg >>= 16;
75	build_segment_config(str, segcfg);
76	seq_printf(m, "   5      00000000    1G       %s\n", str);
77
78	return 0;
79}
80
81static int segments_open(struct inode *inode, struct file *file)
82{
83	return single_open(file, show_segments, NULL);
84}
85
86static const struct file_operations segments_fops = {
87	.open		= segments_open,
88	.read		= seq_read,
89	.llseek		= seq_lseek,
90	.release	= single_release,
91};
92
93static int __init segments_info(void)
94{
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