From 57f0f512b273f60d52568b8c6b77e17f5636edc0 Mon Sep 17 00:00:00 2001
From: André Fabian Silva Delgado <emulatorman@parabola.nu>
Date: Wed, 5 Aug 2015 17:04:01 -0300
Subject: Initial import

---
 arch/blackfin/kernel/irqchip.c | 132 +++++++++++++++++++++++++++++++++++++++++
 1 file changed, 132 insertions(+)
 create mode 100644 arch/blackfin/kernel/irqchip.c

(limited to 'arch/blackfin/kernel/irqchip.c')

diff --git a/arch/blackfin/kernel/irqchip.c b/arch/blackfin/kernel/irqchip.c
new file mode 100644
index 000000000..0ba25764b
--- /dev/null
+++ b/arch/blackfin/kernel/irqchip.c
@@ -0,0 +1,132 @@
+/*
+ * Copyright 2005-2009 Analog Devices Inc.
+ *
+ * Licensed under the GPL-2 or later
+ */
+
+#include <linux/kernel_stat.h>
+#include <linux/module.h>
+#include <linux/random.h>
+#include <linux/seq_file.h>
+#include <linux/kallsyms.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/seq_file.h>
+#include <asm/irq_handler.h>
+#include <asm/trace.h>
+#include <asm/pda.h>
+
+static atomic_t irq_err_count;
+void ack_bad_irq(unsigned int irq)
+{
+	atomic_inc(&irq_err_count);
+	printk(KERN_ERR "IRQ: spurious interrupt %d\n", irq);
+}
+
+static struct irq_desc bad_irq_desc = {
+	.handle_irq = handle_bad_irq,
+	.lock = __RAW_SPIN_LOCK_UNLOCKED(bad_irq_desc.lock),
+};
+
+#ifdef CONFIG_CPUMASK_OFFSTACK
+/* We are not allocating a variable-sized bad_irq_desc.affinity */
+#error "Blackfin architecture does not support CONFIG_CPUMASK_OFFSTACK."
+#endif
+
+#ifdef CONFIG_PROC_FS
+int arch_show_interrupts(struct seq_file *p, int prec)
+{
+	int j;
+
+	seq_printf(p, "%*s: ", prec, "NMI");
+	for_each_online_cpu(j)
+		seq_printf(p, "%10u ", cpu_pda[j].__nmi_count);
+	seq_printf(p, "  CORE  Non Maskable Interrupt\n");
+	seq_printf(p, "%*s: %10u\n", prec, "ERR", atomic_read(&irq_err_count));
+	return 0;
+}
+#endif
+
+#ifdef CONFIG_DEBUG_STACKOVERFLOW
+static void check_stack_overflow(int irq)
+{
+	/* Debugging check for stack overflow: is there less than STACK_WARN free? */
+	long sp = __get_SP() & (THREAD_SIZE - 1);
+
+	if (unlikely(sp < (sizeof(struct thread_info) + STACK_WARN))) {
+		dump_stack();
+		pr_emerg("irq%i: possible stack overflow only %ld bytes free\n",
+			irq, sp - sizeof(struct thread_info));
+	}
+}
+#else
+static inline void check_stack_overflow(int irq) { }
+#endif
+
+#ifndef CONFIG_IPIPE
+static void maybe_lower_to_irq14(void)
+{
+	unsigned short pending, other_ints;
+
+	/*
+	 * If we're the only interrupt running (ignoring IRQ15 which
+	 * is for syscalls), lower our priority to IRQ14 so that
+	 * softirqs run at that level.  If there's another,
+	 * lower-level interrupt, irq_exit will defer softirqs to
+	 * that. If the interrupt pipeline is enabled, we are already
+	 * running at IRQ14 priority, so we don't need this code.
+	 */
+	CSYNC();
+	pending = bfin_read_IPEND() & ~0x8000;
+	other_ints = pending & (pending - 1);
+	if (other_ints == 0)
+		lower_to_irq14();
+}
+#else
+static inline void maybe_lower_to_irq14(void) { }
+#endif
+
+/*
+ * do_IRQ handles all hardware IRQs.  Decoded IRQs should not
+ * come via this function.  Instead, they should provide their
+ * own 'handler'
+ */
+#ifdef CONFIG_DO_IRQ_L1
+__attribute__((l1_text))
+#endif
+asmlinkage void asm_do_IRQ(unsigned int irq, struct pt_regs *regs)
+{
+	struct pt_regs *old_regs = set_irq_regs(regs);
+
+	irq_enter();
+
+	check_stack_overflow(irq);
+
+	/*
+	 * Some hardware gives randomly wrong interrupts.  Rather
+	 * than crashing, do something sensible.
+	 */
+	if (irq >= NR_IRQS)
+		handle_bad_irq(irq, &bad_irq_desc);
+	else
+		generic_handle_irq(irq);
+
+	maybe_lower_to_irq14();
+
+	irq_exit();
+
+	set_irq_regs(old_regs);
+}
+
+void __init init_IRQ(void)
+{
+	init_arch_irq();
+
+#ifdef CONFIG_DEBUG_BFIN_HWTRACE_EXPAND
+	/* Now that evt_ivhw is set up, turn this on */
+	trace_buff_offset = 0;
+	bfin_write_TBUFCTL(BFIN_TRACE_ON);
+	printk(KERN_INFO "Hardware Trace expanded to %ik\n",
+	  1 << CONFIG_DEBUG_BFIN_HWTRACE_EXPAND_LEN);
+#endif
+}
-- 
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