1/*
 2 * Support for hardware-assisted userspace interrupt masking.
 3 *
 4 * Copyright (C) 2010  Paul Mundt
 5 *
 6 * This file is subject to the terms and conditions of the GNU General Public
 7 * License.  See the file "COPYING" in the main directory of this archive
 8 * for more details.
 9 */
10#define pr_fmt(fmt) "intc: " fmt
11
12#include <linux/errno.h>
13#include <linux/sysdev.h>
14#include <linux/init.h>
15#include <linux/io.h>
 
16#include <asm/sizes.h>
17#include "internals.h"
18
19static void __iomem *uimask;
20
21static ssize_t
22show_intc_userimask(struct sysdev_class *cls,
23		    struct sysdev_class_attribute *attr, char *buf)
24{
25	return sprintf(buf, "%d\n", (__raw_readl(uimask) >> 4) & 0xf);
26}
27
28static ssize_t
29store_intc_userimask(struct sysdev_class *cls,
30		     struct sysdev_class_attribute *attr,
31		     const char *buf, size_t count)
32{
33	unsigned long level;
34
35	level = simple_strtoul(buf, NULL, 10);
36
37	/*
38	 * Minimal acceptable IRQ levels are in the 2 - 16 range, but
39	 * these are chomped so as to not interfere with normal IRQs.
40	 *
41	 * Level 1 is a special case on some CPUs in that it's not
42	 * directly settable, but given that USERIMASK cuts off below a
43	 * certain level, we don't care about this limitation here.
44	 * Level 0 on the other hand equates to user masking disabled.
45	 *
46	 * We use the default priority level as a cut off so that only
47	 * special case opt-in IRQs can be mangled.
48	 */
49	if (level >= intc_get_dfl_prio_level())
50		return -EINVAL;
51
52	__raw_writel(0xa5 << 24 | level << 4, uimask);
53
54	return count;
55}
56
57static SYSDEV_CLASS_ATTR(userimask, S_IRUSR | S_IWUSR,
58			 show_intc_userimask, store_intc_userimask);
59
60
61static int __init userimask_sysdev_init(void)
62{
63	if (unlikely(!uimask))
64		return -ENXIO;
65
66	return sysdev_class_create_file(&intc_sysdev_class, &attr_userimask);
67}
68late_initcall(userimask_sysdev_init);
69
70int register_intc_userimask(unsigned long addr)
71{
72	if (unlikely(uimask))
73		return -EBUSY;
74
75	uimask = ioremap_nocache(addr, SZ_4K);
76	if (unlikely(!uimask))
77		return -ENOMEM;
78
79	pr_info("userimask support registered for levels 0 -> %d\n",
80		intc_get_dfl_prio_level() - 1);
81
82	return 0;
83}

 1/*
 2 * Support for hardware-assisted userspace interrupt masking.
 3 *
 4 * Copyright (C) 2010  Paul Mundt
 5 *
 6 * This file is subject to the terms and conditions of the GNU General Public
 7 * License.  See the file "COPYING" in the main directory of this archive
 8 * for more details.
 9 */
10#define pr_fmt(fmt) "intc: " fmt
11
12#include <linux/errno.h>
13#include <linux/device.h>
14#include <linux/init.h>
15#include <linux/io.h>
16#include <linux/stat.h>
17#include <asm/sizes.h>
18#include "internals.h"
19
20static void __iomem *uimask;
21
22static ssize_t
23show_intc_userimask(struct device *dev,
24		    struct device_attribute *attr, char *buf)
25{
26	return sprintf(buf, "%d\n", (__raw_readl(uimask) >> 4) & 0xf);
27}
28
29static ssize_t
30store_intc_userimask(struct device *dev,
31		     struct device_attribute *attr,
32		     const char *buf, size_t count)
33{
34	unsigned long level;
35
36	level = simple_strtoul(buf, NULL, 10);
37
38	/*
39	 * Minimal acceptable IRQ levels are in the 2 - 16 range, but
40	 * these are chomped so as to not interfere with normal IRQs.
41	 *
42	 * Level 1 is a special case on some CPUs in that it's not
43	 * directly settable, but given that USERIMASK cuts off below a
44	 * certain level, we don't care about this limitation here.
45	 * Level 0 on the other hand equates to user masking disabled.
46	 *
47	 * We use the default priority level as a cut off so that only
48	 * special case opt-in IRQs can be mangled.
49	 */
50	if (level >= intc_get_dfl_prio_level())
51		return -EINVAL;
52
53	__raw_writel(0xa5 << 24 | level << 4, uimask);
54
55	return count;
56}
57
58static DEVICE_ATTR(userimask, S_IRUSR | S_IWUSR,
59		   show_intc_userimask, store_intc_userimask);
60
61
62static int __init userimask_sysdev_init(void)
63{
64	if (unlikely(!uimask))
65		return -ENXIO;
66
67	return device_create_file(intc_subsys.dev_root, &dev_attr_userimask);
68}
69late_initcall(userimask_sysdev_init);
70
71int register_intc_userimask(unsigned long addr)
72{
73	if (unlikely(uimask))
74		return -EBUSY;
75
76	uimask = ioremap_nocache(addr, SZ_4K);
77	if (unlikely(!uimask))
78		return -ENOMEM;
79
80	pr_info("userimask support registered for levels 0 -> %d\n",
81		intc_get_dfl_prio_level() - 1);
82
83	return 0;
84}