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Commit 29f9087c authored by Steven J. Hill's avatar Steven J. Hill Committed by Ralf Baechle
Browse files

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: default avatarJohn 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: default avatarJames Hogan <james.hogan@imgtec.com>
Signed-off-by: default avatarSteven J. Hill <Steven.Hill@imgtec.com>
Signed-off-by: default avatarMarkos Chandras <markos.chandras@imgtec.com>
parent 75b5b5e0

arch/mips/kernel/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -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

arch/mips/kernel/segment.c

0 → 100644
+110 −0
Original line number Diff line number Diff line 
/*

 * 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);