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MIPS: Add debugfs file to print the segmentation control registers 

Add a new mips/segments debugfs file to print the 6 segmentation
control registers for supported cores. A sample from a proAptiv core
is given below:

Signed-off-by: John Crispin <blogic@openwrt.org>
Patchwork: http://patchwork.linux-mips.org/patch/6137/
Segment   Virtual    Size   Access Mode   Physical   Caching   EU
-------   -------    ----   -----------   --------   -------   --
   0      e0000000   512M      MK           UND         U       0
   1      c0000000   512M      MSK          UND         U       0
   2      a0000000   512M      UK           000         2       0
   3      80000000   512M      UK           000         3       0
   4      40000000    1G       MUSK         UND         U       1
   5      00000000    1G       MUSK         UND         U       1

Reviewed-by: James Hogan <james.hogan@imgtec.com>
Signed-off-by: Steven J. Hill <Steven.Hill@imgtec.com>
Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
This commit is contained in:
Steven J. Hill 2013-11-14 16:12:32 +00:00 committed by Ralf Baechle
parent 75b5b5e0a2
commit 29f9087c52
2 changed files with 111 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
arch/mips/kernel/Makefile
View File

@ -30,6 +30,7 @@ obj-$(CONFIG_CSRC_R4K) += csrc-r4k.o
obj-$(CONFIG_CSRC_SB1250) += csrc-sb1250.o
obj-$(CONFIG_SYNC_R4K) += sync-r4k.o
obj-$(CONFIG_DEBUG_FS) += segment.o
obj-$(CONFIG_STACKTRACE) += stacktrace.o
obj-$(CONFIG_MODULES) += mips_ksyms.o module.o
obj-$(CONFIG_MODULES_USE_ELF_RELA) += module-rela.o

110
arch/mips/kernel/segment.c Normal file
View File

@ -0,0 +1,110 @@
/*
* 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/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.
*/
if ((am == 0) || (am > 3)) {
str += sprintf(str, " %03lx",
((cfg & MIPS_SEGCFG_PA) >> MIPS_SEGCFG_PA_SHIFT));
str += sprintf(str, " %01ld",
((cfg & MIPS_SEGCFG_C) >> MIPS_SEGCFG_C_SHIFT));
} else {
str += sprintf(str, " UND");
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)
{
extern struct dentry *mips_debugfs_dir;
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);