From 849369d6c66d3054688672f97d31fceb8e8230fb Mon Sep 17 00:00:00 2001
From: root <root@artemis.panaceas.org>
Date: Fri, 25 Dec 2015 04:40:36 +0000
Subject: initial_commit

---
 arch/alpha/kernel/irq.c | 131 ++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 131 insertions(+)
 create mode 100644 arch/alpha/kernel/irq.c

(limited to 'arch/alpha/kernel/irq.c')

diff --git a/arch/alpha/kernel/irq.c b/arch/alpha/kernel/irq.c
new file mode 100644
index 00000000..381431a2
--- /dev/null
+++ b/arch/alpha/kernel/irq.c
@@ -0,0 +1,131 @@
+/*
+ *	linux/arch/alpha/kernel/irq.c
+ *
+ *	Copyright (C) 1995 Linus Torvalds
+ *
+ * This file contains the code used by various IRQ handling routines:
+ * asking for different IRQ's should be done through these routines
+ * instead of just grabbing them. Thus setups with different IRQ numbers
+ * shouldn't result in any weird surprises, and installing new handlers
+ * should be easier.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/errno.h>
+#include <linux/kernel_stat.h>
+#include <linux/signal.h>
+#include <linux/sched.h>
+#include <linux/ptrace.h>
+#include <linux/interrupt.h>
+#include <linux/random.h>
+#include <linux/init.h>
+#include <linux/irq.h>
+#include <linux/proc_fs.h>
+#include <linux/seq_file.h>
+#include <linux/profile.h>
+#include <linux/bitops.h>
+
+#include <asm/system.h>
+#include <asm/io.h>
+#include <asm/uaccess.h>
+
+volatile unsigned long irq_err_count;
+DEFINE_PER_CPU(unsigned long, irq_pmi_count);
+
+void ack_bad_irq(unsigned int irq)
+{
+	irq_err_count++;
+	printk(KERN_CRIT "Unexpected IRQ trap at vector %u\n", irq);
+}
+
+#ifdef CONFIG_SMP 
+static char irq_user_affinity[NR_IRQS];
+
+int irq_select_affinity(unsigned int irq)
+{
+	struct irq_data *data = irq_get_irq_data(irq);
+	struct irq_chip *chip;
+	static int last_cpu;
+	int cpu = last_cpu + 1;
+
+	if (!data)
+		return 1;
+	chip = irq_data_get_irq_chip(data);
+
+	if (!chip->irq_set_affinity || irq_user_affinity[irq])
+		return 1;
+
+	while (!cpu_possible(cpu) ||
+	       !cpumask_test_cpu(cpu, irq_default_affinity))
+		cpu = (cpu < (NR_CPUS-1) ? cpu + 1 : 0);
+	last_cpu = cpu;
+
+	cpumask_copy(data->affinity, cpumask_of(cpu));
+	chip->irq_set_affinity(data, cpumask_of(cpu), false);
+	return 0;
+}
+#endif /* CONFIG_SMP */
+
+int arch_show_interrupts(struct seq_file *p, int prec)
+{
+	int j;
+
+#ifdef CONFIG_SMP
+	seq_puts(p, "IPI: ");
+	for_each_online_cpu(j)
+		seq_printf(p, "%10lu ", cpu_data[j].ipi_count);
+	seq_putc(p, '\n');
+#endif
+	seq_puts(p, "PMI: ");
+	for_each_online_cpu(j)
+		seq_printf(p, "%10lu ", per_cpu(irq_pmi_count, j));
+	seq_puts(p, "          Performance Monitoring\n");
+	seq_printf(p, "ERR: %10lu\n", irq_err_count);
+	return 0;
+}
+
+/*
+ * handle_irq handles all normal device IRQ's (the special
+ * SMP cross-CPU interrupts have their own specific
+ * handlers).
+ */
+
+#define MAX_ILLEGAL_IRQS 16
+
+void
+handle_irq(int irq)
+{	
+	/* 
+	 * We ack quickly, we don't want the irq controller
+	 * thinking we're snobs just because some other CPU has
+	 * disabled global interrupts (we have already done the
+	 * INT_ACK cycles, it's too late to try to pretend to the
+	 * controller that we aren't taking the interrupt).
+	 *
+	 * 0 return value means that this irq is already being
+	 * handled by some other CPU. (or is disabled)
+	 */
+	static unsigned int illegal_count=0;
+	struct irq_desc *desc = irq_to_desc(irq);
+	
+	if (!desc || ((unsigned) irq > ACTUAL_NR_IRQS &&
+	    illegal_count < MAX_ILLEGAL_IRQS)) {
+		irq_err_count++;
+		illegal_count++;
+		printk(KERN_CRIT "device_interrupt: invalid interrupt %d\n",
+		       irq);
+		return;
+	}
+
+	/*
+	 * From here we must proceed with IPL_MAX. Note that we do not
+	 * explicitly enable interrupts afterwards - some MILO PALcode
+	 * (namely LX164 one) seems to have severe problems with RTI
+	 * at IPL 0.
+	 */
+	local_irq_disable();
+	irq_enter();
+	generic_handle_irq_desc(irq, desc);
+	irq_exit();
+}
-- 
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