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

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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: nicolas Pitre <nico@linaro.org>
This commit is contained in:
Nicolas Pitre 2012-04-12 03:04:28 -04:00
parent 2726143514
commit b22537c682
3 changed files with 80 additions and 0 deletions
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8
arch/arm/Kconfig
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@ -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

1
arch/arm/common/Makefile
View File

@ -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

71
arch/arm/common/bL_switcher_dummy_if.c Normal file
View File

@ -0,0 +1,71 @@
/*
* 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);