sh: intc: userimask support.
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>
diff --git a/drivers/sh/intc.c b/drivers/sh/intc.c
index 65e1582..77d10ac 100644
--- a/drivers/sh/intc.c
+++ b/drivers/sh/intc.c
@@ -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 @@
#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 @@
/* 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 @@
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 @@
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;