[PATCH] xtensa: Architecture support for Tensilica Xtensa Part 3

The attached patches provides part 3 of an architecture implementation for the
Tensilica Xtensa CPU series.

Signed-off-by: Chris Zankel <chris@zankel.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 192 insertions, 0 deletions

diff --git a/arch/xtensa/kernel/irq.c b/arch/xtensa/kernel/irq.c
new file mode 100644
index 000000000000..4cbf6d91571f
--- /dev/null
+++ b/arch/xtensa/kernel/irq.c
@@ -0,0 +1,192 @@
+/*
+ * linux/arch/xtensa/kernel/irq.c
+ *
+ * Xtensa built-in interrupt controller and some generic functions copied
+ * from i386.
+ *
+ * Copyright (C) 2002 - 2005 Tensilica, Inc.
+ * Copyright (C) 1992, 1998 Linus Torvalds, Ingo Molnar
+ *
+ *
+ * Chris Zankel <chris@zankel.net>
+ * Kevin Chea
+ *
+ */
+
+#include <linux/module.h>
+#include <linux/seq_file.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/kernel_stat.h>
+
+#include <asm/uaccess.h>
+#include <asm/platform.h>
+
+static void enable_xtensa_irq(unsigned int irq);
+static void disable_xtensa_irq(unsigned int irq);
+static void mask_and_ack_xtensa(unsigned int irq);
+static void end_xtensa_irq(unsigned int irq);
+
+static unsigned int cached_irq_mask;
+
+atomic_t irq_err_count;
+
+/*
+ * 'what should we do if we get a hw irq event on an illegal vector'.
+ * each architecture has to answer this themselves.
+ */
+void ack_bad_irq(unsigned int irq)
+{
+          printk("unexpected IRQ trap at vector %02x\n", irq);
+}
+
+/*
+ * do_IRQ handles all normal device IRQ's (the special
+ * SMP cross-CPU interrupts have their own specific
+ * handlers).
+ */
+
+unsigned int  do_IRQ(int irq, struct pt_regs *regs)
+{
+	irq_enter();
+
+#ifdef CONFIG_DEBUG_STACKOVERFLOW
+	/* Debugging check for stack overflow: is there less than 1KB free? */
+	{
+		unsigned long sp;
+
+		__asm__ __volatile__ ("mov %0, a1\n" : "=a" (sp));
+		sp &= THREAD_SIZE - 1;
+
+		if (unlikely(sp < (sizeof(thread_info) + 1024)))
+			printk("Stack overflow in do_IRQ: %ld\n",
+			       sp - sizeof(struct thread_info));
+	}
+#endif
+
+	__do_IRQ(irq, regs);
+
+	irq_exit();
+
+	return 1;
+}
+
+/*
+ * Generic, controller-independent functions:
+ */
+
+int show_interrupts(struct seq_file *p, void *v)
+{
+	int i = *(loff_t *) v, j;
+	struct irqaction * action;
+	unsigned long flags;
+
+	if (i == 0) {
+		seq_printf(p, "           ");
+		for (j=0; j<NR_CPUS; j++)
+			if (cpu_online(j))
+				seq_printf(p, "CPU%d       ",j);
+		seq_putc(p, '\n');
+	}
+
+	if (i < NR_IRQS) {
+		spin_lock_irqsave(&irq_desc[i].lock, flags);
+		action = irq_desc[i].action;
+		if (!action)
+			goto skip;
+		seq_printf(p, "%3d: ",i);
+#ifndef CONFIG_SMP
+		seq_printf(p, "%10u ", kstat_irqs(i));
+#else
+		for (j = 0; j < NR_CPUS; j++)
+			if (cpu_online(j))
+				seq_printf(p, "%10u ", kstat_cpu(j).irqs[i]);
+#endif
+		seq_printf(p, " %14s", irq_desc[i].handler->typename);
+		seq_printf(p, "  %s", action->name);
+
+		for (action=action->next; action; action = action->next)
+			seq_printf(p, ", %s", action->name);
+
+		seq_putc(p, '\n');
+skip:
+		spin_unlock_irqrestore(&irq_desc[i].lock, flags);
+	} else if (i == NR_IRQS) {
+		seq_printf(p, "NMI: ");
+		for (j = 0; j < NR_CPUS; j++)
+			if (cpu_online(j))
+				seq_printf(p, "%10u ", nmi_count(j));
+		seq_putc(p, '\n');
+		seq_printf(p, "ERR: %10u\n", atomic_read(&irq_err_count));
+	}
+	return 0;
+}
+/* shutdown is same as "disable" */
+#define shutdown_xtensa_irq disable_xtensa_irq
+
+static unsigned int startup_xtensa_irq(unsigned int irq)
+{
+	enable_xtensa_irq(irq);
+	return 0;               /* never anything pending */
+}
+
+static struct hw_interrupt_type xtensa_irq_type = {
+	"Xtensa-IRQ",
+	startup_xtensa_irq,
+	shutdown_xtensa_irq,
+	enable_xtensa_irq,
+	disable_xtensa_irq,
+	mask_and_ack_xtensa,
+	end_xtensa_irq
+};
+
+static inline void mask_irq(unsigned int irq)
+{
+	cached_irq_mask &= ~(1 << irq);
+	set_sr (cached_irq_mask, INTENABLE);
+}
+
+static inline void unmask_irq(unsigned int irq)
+{
+	cached_irq_mask |= 1 << irq;
+	set_sr (cached_irq_mask, INTENABLE);
+}
+
+static void disable_xtensa_irq(unsigned int irq)
+{
+	unsigned long flags;
+	local_save_flags(flags);
+	mask_irq(irq);
+	local_irq_restore(flags);
+}
+
+static void enable_xtensa_irq(unsigned int irq)
+{
+	unsigned long flags;
+	local_save_flags(flags);
+	unmask_irq(irq);
+	local_irq_restore(flags);
+}
+
+static void mask_and_ack_xtensa(unsigned int irq)
+{
+        disable_xtensa_irq(irq);
+}
+
+static void end_xtensa_irq(unsigned int irq)
+{
+        enable_xtensa_irq(irq);
+}
+
+
+void __init init_IRQ(void)
+{
+	int i;
+
+	for (i=0; i < XTENSA_NR_IRQS; i++)
+		irq_desc[i].handler = &xtensa_irq_type;
+
+	cached_irq_mask = 0;
+
+	platform_init_irq();
+}