segment.c
/*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*
* Copyright (C) 2013 Imagination Technologies Ltd.
*/
#include <linux/kernel.h>
#include <linux/debugfs.h>
#include <linux/seq_file.h>
#include <asm/cpu.h>
#include <asm/debug.h>
#include <asm/mipsregs.h>
static void build_segment_config(char *str, unsigned int cfg)
{
unsigned int am;
static const char * const am_str[] = {
"UK", "MK", "MSK", "MUSK", "MUSUK", "USK",
"RSRVD", "UUSK"};
/* Segment access mode. */
am = (cfg & MIPS_SEGCFG_AM) >> MIPS_SEGCFG_AM_SHIFT;
str += sprintf(str, "%-5s", am_str[am]);
/*
* Access modes MK, MSK and MUSK are mapped segments. Therefore
* there is no direct physical address mapping unless it becomes
* unmapped uncached at error level due to EU.
*/
if ((am == 0) || (am > 3) || (cfg & MIPS_SEGCFG_EU))
str += sprintf(str, " %03lx",
((cfg & MIPS_SEGCFG_PA) >> MIPS_SEGCFG_PA_SHIFT));
else
str += sprintf(str, " UND");
if ((am == 0) || (am > 3))
str += sprintf(str, " %01ld",
((cfg & MIPS_SEGCFG_C) >> MIPS_SEGCFG_C_SHIFT));
else
str += sprintf(str, " U");
/* Exception configuration. */
str += sprintf(str, " %01ld\n",
((cfg & MIPS_SEGCFG_EU) >> MIPS_SEGCFG_EU_SHIFT));
}
static int show_segments(struct seq_file *m, void *v)
{
unsigned int segcfg;
char str[42];
seq_puts(m, "Segment Virtual Size Access Mode Physical Caching EU\n");
seq_puts(m, "------- ------- ---- ----------- -------- ------- --\n");
segcfg = read_c0_segctl0();
build_segment_config(str, segcfg);
seq_printf(m, " 0 e0000000 512M %s", str);
segcfg >>= 16;
build_segment_config(str, segcfg);
seq_printf(m, " 1 c0000000 512M %s", str);
segcfg = read_c0_segctl1();
build_segment_config(str, segcfg);
seq_printf(m, " 2 a0000000 512M %s", str);
segcfg >>= 16;
build_segment_config(str, segcfg);
seq_printf(m, " 3 80000000 512M %s", str);
segcfg = read_c0_segctl2();
build_segment_config(str, segcfg);
seq_printf(m, " 4 40000000 1G %s", str);
segcfg >>= 16;
build_segment_config(str, segcfg);
seq_printf(m, " 5 00000000 1G %s\n", str);
return 0;
}
static int segments_open(struct inode *inode, struct file *file)
{
return single_open(file, show_segments, NULL);
}
static const struct file_operations segments_fops = {
.open = segments_open,
.read = seq_read,
.llseek = seq_lseek,
.release = single_release,
};
static int __init segments_info(void)
{
struct dentry *segments;
if (cpu_has_segments) {
if (!mips_debugfs_dir)
return -ENODEV;
segments = debugfs_create_file("segments", S_IRUGO,
mips_debugfs_dir, NULL,
&segments_fops);
if (!segments)
return -ENOMEM;
}
return 0;
}
device_initcall(segments_info);