arm64: IRQ handling

This patch adds the support for IRQ handling. The actual interrupt
controller will be part of a separate patch (going into
drivers/irqchip/).

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Tony Lindgren <tony@atomide.com>
Acked-by: Nicolas Pitre <nico@linaro.org>
Acked-by: Olof Johansson <olof@lixom.net>
Acked-by: Santosh Shilimkar <santosh.shilimkar@ti.com>

4 files changed, 230 insertions, 0 deletions

diff --git a/arch/arm64/include/asm/hardirq.h b/arch/arm64/include/asm/hardirq.h
new file mode 100644
index 000000000000..c6c95145c17c
--- /dev/null
+++ b/arch/arm64/include/asm/hardirq.h
@@ -0,0 +1,47 @@
+/*
+ * Copyright (C) 2012 ARM Ltd.
+ *
+ * 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.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+#ifndef __ASM_HARDIRQ_H
+#define __ASM_HARDIRQ_H
+
+#include <linux/cache.h>
+#include <linux/threads.h>
+#include <asm/irq.h>
+
+typedef struct {
+        unsigned int __softirq_pending;
+} ____cacheline_aligned irq_cpustat_t;
+
+#include <linux/irq_cpustat.h>  /* Standard mappings for irq_cpustat_t above */
+
+#define __inc_irq_stat(cpu, member)     __IRQ_STAT(cpu, member)++
+#define __get_irq_stat(cpu, member)     __IRQ_STAT(cpu, member)
+
+#ifdef CONFIG_SMP
+u64 smp_irq_stat_cpu(unsigned int cpu);
+#define arch_irq_stat_cpu       smp_irq_stat_cpu
+#endif
+
+#define __ARCH_IRQ_EXIT_IRQS_DISABLED   1
+
+static inline void ack_bad_irq(unsigned int irq)
+{
+        extern unsigned long irq_err_count;
+        irq_err_count++;
+}
+
+extern void handle_IRQ(unsigned int, struct pt_regs *);
+
+#endif /* __ASM_HARDIRQ_H */
diff --git a/arch/arm64/include/asm/irq.h b/arch/arm64/include/asm/irq.h
new file mode 100644
index 000000000000..a4e1cad3202a
--- /dev/null
+++ b/arch/arm64/include/asm/irq.h
@@ -0,0 +1,8 @@
+#ifndef __ASM_IRQ_H
+#define __ASM_IRQ_H
+
+#include <asm-generic/irq.h>
+
+extern void (*handle_arch_irq)(struct pt_regs *);
+
+#endif
diff --git a/arch/arm64/include/asm/irqflags.h b/arch/arm64/include/asm/irqflags.h
new file mode 100644
index 000000000000..aa11943b8502
--- /dev/null
+++ b/arch/arm64/include/asm/irqflags.h
@@ -0,0 +1,91 @@
+/*
+ * Copyright (C) 2012 ARM Ltd.
+ *
+ * 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.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+#ifndef __ASM_IRQFLAGS_H
+#define __ASM_IRQFLAGS_H
+
+#ifdef __KERNEL__
+
+#include <asm/ptrace.h>
+
+/*
+ * CPU interrupt mask handling.
+ */
+static inline unsigned long arch_local_irq_save(void)
+{
+        unsigned long flags;
+        asm volatile(
+                "mrs    %0, daif                // arch_local_irq_save\n"
+                "msr    daifset, #2"
+                : "=r" (flags)
+                :
+                : "memory");
+        return flags;
+}
+
+static inline void arch_local_irq_enable(void)
+{
+        asm volatile(
+                "msr    daifclr, #2             // arch_local_irq_enable"
+                :
+                :
+                : "memory");
+}
+
+static inline void arch_local_irq_disable(void)
+{
+        asm volatile(
+                "msr    daifset, #2             // arch_local_irq_disable"
+                :
+                :
+                : "memory");
+}
+
+#define local_fiq_enable()      asm("msr        daifclr, #1" : : : "memory")
+#define local_fiq_disable()     asm("msr        daifset, #1" : : : "memory")
+
+/*
+ * Save the current interrupt enable state.
+ */
+static inline unsigned long arch_local_save_flags(void)
+{
+        unsigned long flags;
+        asm volatile(
+                "mrs    %0, daif                // arch_local_save_flags"
+                : "=r" (flags)
+                :
+                : "memory");
+        return flags;
+}
+
+/*
+ * restore saved IRQ state
+ */
+static inline void arch_local_irq_restore(unsigned long flags)
+{
+        asm volatile(
+                "msr    daif, %0                // arch_local_irq_restore"
+        :
+        : "r" (flags)
+        : "memory");
+}
+
+static inline int arch_irqs_disabled_flags(unsigned long flags)
+{
+        return flags & PSR_I_BIT;
+}
+
+#endif
+#endif
diff --git a/arch/arm64/kernel/irq.c b/arch/arm64/kernel/irq.c
new file mode 100644
index 000000000000..0373c6609eaf
--- /dev/null
+++ b/arch/arm64/kernel/irq.c
@@ -0,0 +1,84 @@
+/*
+ * Based on arch/arm/kernel/irq.c
+ *
+ * Copyright (C) 1992 Linus Torvalds
+ * Modifications for ARM processor Copyright (C) 1995-2000 Russell King.
+ * Support for Dynamic Tick Timer Copyright (C) 2004-2005 Nokia Corporation.
+ * Dynamic Tick Timer written by Tony Lindgren <tony@atomide.com> and
+ * Tuukka Tikkanen <tuukka.tikkanen@elektrobit.com>.
+ * Copyright (C) 2012 ARM Ltd.
+ *
+ * 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.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <linux/kernel_stat.h>
+#include <linux/irq.h>
+#include <linux/smp.h>
+#include <linux/init.h>
+#include <linux/of_irq.h>
+#include <linux/seq_file.h>
+#include <linux/ratelimit.h>
+
+unsigned long irq_err_count;
+
+int arch_show_interrupts(struct seq_file *p, int prec)
+{
+#ifdef CONFIG_SMP
+        show_ipi_list(p, prec);
+#endif
+        seq_printf(p, "%*s: %10lu\n", prec, "Err", irq_err_count);
+        return 0;
+}
+
+/*
+ * handle_IRQ handles all hardware IRQ's.  Decoded IRQs should
+ * not come via this function.  Instead, they should provide their
+ * own 'handler'.  Used by platform code implementing C-based 1st
+ * level decoding.
+ */
+void handle_IRQ(unsigned int irq, struct pt_regs *regs)
+{
+        struct pt_regs *old_regs = set_irq_regs(regs);
+
+        irq_enter();
+
+        /*
+         * Some hardware gives randomly wrong interrupts.  Rather
+         * than crashing, do something sensible.
+         */
+        if (unlikely(irq >= nr_irqs)) {
+                pr_warn_ratelimited("Bad IRQ%u\n", irq);
+                ack_bad_irq(irq);
+        } else {
+                generic_handle_irq(irq);
+        }
+
+        irq_exit();
+        set_irq_regs(old_regs);
+}
+
+/*
+ * Interrupt controllers supported by the kernel.
+ */
+static const struct of_device_id intctrl_of_match[] __initconst = {
+        /* IRQ controllers { .compatible, .data } info to go here */
+        {}
+};
+
+void __init init_IRQ(void)
+{
+        of_irq_init(intctrl_of_match);
+
+        if (!handle_arch_irq)
+                panic("No interrupt controller found.");
+}