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Commit b22537c6 authored by Nicolas Pitre's avatar Nicolas Pitre
Browse files

ARM: bL_switcher: add a simple /dev user interface for debugging purposes 



Only the basic call to aid debugging.

*** NOT FOR PRODUCTION ***

Usage:

	echo <cpuid>,<clusterid> > /dev/b.L_switcher

where <cpuid> is the logical CPU number, and <clusterid> is 0 for the
first cluster and 1 for the second cluster.

Signed-off-by: default avatarnicolas Pitre <nico@linaro.org>
parent 27261435

arch/arm/Kconfig

+8 −0
Original line number Diff line number Diff line
@@ -1556,6 +1556,14 @@ config BL_SWITCHER 
	  transparently handle transition between a cluster of A15's

	  and a cluster of A7's in a big.LITTLE system.



config BL_SWITCHER_DUMMY_IF

	tristate "Simple big.LITTLE switcher user interface"

	depends on BL_SWITCHER && DEBUG_KERNEL

	help

	  This is a simple and dummy char dev interface to control

	  the big.LITTLE switcher core code.  It is meant for

	  debugging purposes only.



choice

	prompt "Memory split"

	default VMSPLIT_3G

arch/arm/common/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -18,3 +18,4 @@ AFLAGS_mcpm_head.o := -march=armv7-a 
AFLAGS_vlock.o			:= -march=armv7-a

obj-$(CONFIG_TI_PRIV_EDMA)	+= edma.o

obj-$(CONFIG_BL_SWITCHER)	+= bL_switcher.o

obj-$(CONFIG_BL_SWITCHER_DUMMY_IF) += bL_switcher_dummy_if.o

arch/arm/common/bL_switcher_dummy_if.c

0 → 100644
+71 −0
Original line number Diff line number Diff line 
/*

 * arch/arm/common/bL_switcher_dummy_if.c -- b.L switcher dummy interface

 *

 * Created by:	Nicolas Pitre, November 2012

 * Copyright:	(C) 2012-2013  Linaro Limited

 *

 * Dummy interface to user space for debugging purpose only.

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License version 2 as

 * published by the Free Software Foundation.

 */



#include <linux/init.h>

#include <linux/module.h>

#include <linux/fs.h>

#include <linux/miscdevice.h>

#include <asm/uaccess.h>

#include <asm/bL_switcher.h>



static ssize_t bL_switcher_write(struct file *file, const char __user *buf,

			size_t len, loff_t *pos)

{

	unsigned char val[3];

	unsigned int cpu, cluster;

	int ret;



	pr_debug("%s\n", __func__);



	if (len < 3)

		return -EINVAL;



	if (copy_from_user(val, buf, 3))

		return -EFAULT;



	/* format: <cpu#>,<cluster#> */

	if (val[0] < '0' || val[0] > '9' ||

	    val[1] != ',' ||

	    val[2] < '0' || val[2] > '1')

		return -EINVAL;



	cpu = val[0] - '0';

	cluster = val[2] - '0';

	ret = bL_switch_request(cpu, cluster);



	return ret ? : len;

}



static const struct file_operations bL_switcher_fops = {

	.write		= bL_switcher_write,

	.owner	= THIS_MODULE,

};



static struct miscdevice bL_switcher_device = {

	MISC_DYNAMIC_MINOR,

	"b.L_switcher",

	&bL_switcher_fops

};



static int __init bL_switcher_dummy_if_init(void)

{

	return misc_register(&bL_switcher_device);

}



static void __exit bL_switcher_dummy_if_exit(void)

{

	misc_deregister(&bL_switcher_device);

}



module_init(bL_switcher_dummy_if_init);

module_exit(bL_switcher_dummy_if_exit);