85 lines
2.0 KiB
C
85 lines
2.0 KiB
C
|
/*
|
||
|
|
* Support for hardware-assisted userspace interrupt masking.
|
||
|
|
*
|
||
|
|
* Copyright (C) 2010 Paul Mundt
|
||
|
|
*
|
||
|
|
* 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.
|
||
|
|
*/
|
||
|
|
#define pr_fmt(fmt) "intc: " fmt
|
||
|
|
|
||
|
|
#include <linux/errno.h>
|
||
|
|
#include <linux/device.h>
|
||
|
|
#include <linux/init.h>
|
||
|
|
#include <linux/io.h>
|
||
|
|
#include <linux/stat.h>
|
||
|
|
#include <linux/sizes.h>
|
||
|
|
#include "internals.h"
|
||
|
|
|
||
|
|
static void __iomem *uimask;
|
||
|
|
|
||
|
|
static ssize_t
|
||
|
|
show_intc_userimask(struct device *dev,
|
||
|
|
struct device_attribute *attr, char *buf)
|
||
|
|
{
|
||
|
|
return sprintf(buf, "%d\n", (__raw_readl(uimask) >> 4) & 0xf);
|
||
|
|
}
|
||
|
|
|
||
|
|
static ssize_t
|
||
|
|
store_intc_userimask(struct device *dev,
|
||
|
|
struct device_attribute *attr,
|
||
|
|
const char *buf, size_t count)
|
||
|
|
{
|
||
|
|
unsigned long level;
|
||
|
|
|
||
|
|
level = simple_strtoul(buf, NULL, 10);
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Minimal acceptable IRQ levels are in the 2 - 16 range, but
|
||
|
|
* these are chomped so as to not interfere with normal IRQs.
|
||
|
|
*
|
||
|
|
* Level 1 is a special case on some CPUs in that it's not
|
||
|
|
* directly settable, but given that USERIMASK cuts off below a
|
||
|
|
* certain level, we don't care about this limitation here.
|
||
|
|
* Level 0 on the other hand equates to user masking disabled.
|
||
|
|
*
|
||
|
|
* We use the default priority level as a cut off so that only
|
||
|
|
* special case opt-in IRQs can be mangled.
|
||
|
|
*/
|
||
|
|
if (level >= intc_get_dfl_prio_level())
|
||
|
|
return -EINVAL;
|
||
|
|
|
||
|
|
__raw_writel(0xa5 << 24 | level << 4, uimask);
|
||
|
|
|
||
|
|
return count;
|
||
|
|
}
|
||
|
|
|
||
|
|
static DEVICE_ATTR(userimask, S_IRUSR | S_IWUSR,
|
||
|
|
show_intc_userimask, store_intc_userimask);
|
||
|
|
|
||
|
|
|
||
|
|
static int __init userimask_sysdev_init(void)
|
||
|
|
{
|
||
|
|
if (unlikely(!uimask))
|
||
|
|
return -ENXIO;
|
||
|
|
|
||
|
|
return device_create_file(intc_subsys.dev_root, &dev_attr_userimask);
|
||
|
|
}
|
||
|
|
late_initcall(userimask_sysdev_init);
|
||
|
|
|
||
|
|
int register_intc_userimask(unsigned long addr)
|
||
|
|
{
|
||
|
|
if (unlikely(uimask))
|
||
|
|
return -EBUSY;
|
||
|
|
|
||
|
|
uimask = ioremap(addr, SZ_4K);
|
||
|
|
if (unlikely(!uimask))
|
||
|
|
return -ENOMEM;
|
||
|
|
|
||
|
|
pr_info("userimask support registered for levels 0 -> %d\n",
|
||
|
|
intc_get_dfl_prio_level() - 1);
|
||
|
|
|
||
|
|
return 0;
|
||
|
|
}
|