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sh: intc: userimask support.

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This adds support for hardware-assisted userspace irq masking for
special priority levels. Due to the SR.IMASK interactivity, only some
platforms implement this in hardware (including but not limited to
SH-4A interrupt controllers, and ARM-based SH-Mobile CPUs). Each CPU
needs to wire this up on its own, for now only SH7786 is wired up as an
example.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>
This commit is contained in:
Paul Mundt
2010-04-13 14:43:03 +09:00
parent 12129fea50
commit 43b8774dc4
5 changed files with 94 additions and 2 deletions
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69
drivers/sh/intc.c
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@@ -27,6 +27,7 @@
#include <linux/topology.h>
#include <linux/bitmap.h>
#include <linux/cpumask.h>
#include <asm/sizes.h>
#define _INTC_MK(fn, mode, addr_e, addr_d, width, shift) \
((shift) | ((width) << 5) | ((fn) << 9) | ((mode) << 13) | \
@@ -94,7 +95,8 @@ static DEFINE_SPINLOCK(vector_lock);
#define SMP_NR(d, x) 1
#endif
static unsigned int intc_prio_level[NR_IRQS]; /* for now */
static unsigned int intc_prio_level[NR_IRQS]; /* for now */
static unsigned int default_prio_level = 2; /* 2 - 16 */
static unsigned long ack_handle[NR_IRQS];
static inline struct intc_desc_int *get_intc_desc(unsigned int irq)
@@ -787,7 +789,7 @@ static void __init intc_register_irq(struct intc_desc *desc,
/* set priority level
* - this needs to be at least 2 for 5-bit priorities on 7780
*/
intc_prio_level[irq] = 2;
intc_prio_level[irq] = default_prio_level;
/* enable secondary masking method if present */
if (data[!primary])
@@ -1037,6 +1039,64 @@ err0:
return -ENOMEM;
}
#ifdef CONFIG_INTC_USERIMASK
static void __iomem *uimask;
int register_intc_userimask(unsigned long addr)
{
if (unlikely(uimask))
return -EBUSY;
uimask = ioremap_nocache(addr, SZ_4K);
if (unlikely(!uimask))
return -ENOMEM;
pr_info("intc: userimask support registered for levels 0 -> %d\n",
default_prio_level - 1);
return 0;
}
static ssize_t
show_intc_userimask(struct sysdev_class *cls,
struct sysdev_class_attribute *attr, char *buf)
{
return sprintf(buf, "%d\n", (__raw_readl(uimask) >> 4) & 0xf);
}
static ssize_t
store_intc_userimask(struct sysdev_class *cls,
struct sysdev_class_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 default_prio_level as a cut off so that only special
* case opt-in IRQs can be mangled.
*/
if (level >= default_prio_level)
return -EINVAL;
__raw_writel(0xa5 << 24 | level << 4, uimask);
return count;
}
static SYSDEV_CLASS_ATTR(userimask, S_IRUSR | S_IWUSR,
show_intc_userimask, store_intc_userimask);
#endif
static ssize_t
show_intc_name(struct sys_device *dev, struct sysdev_attribute *attr, char *buf)
{
@@ -1108,6 +1168,11 @@ static int __init register_intc_sysdevs(void)
int id = 0;
error = sysdev_class_register(&intc_sysdev_class);
#ifdef CONFIG_INTC_USERIMASK
if (!error && uimask)
error = sysdev_class_create_file(&intc_sysdev_class,
&attr_userimask);
#endif
if (!error) {
list_for_each_entry(d, &intc_list, list) {
d->sysdev.id = id;