1 files changed, 127 insertions, 0 deletions
diff --git a/arch/alpha/kernel/irq_pyxis.c b/arch/alpha/kernel/irq_pyxis.c
new file mode 100644
index 00000000000..146a20b9e3d
--- /dev/null
+++ b/arch/alpha/kernel/irq_pyxis.c
@@ -0,0 +1,127 @@
+/*
+ *	linux/arch/alpha/kernel/irq_pyxis.c
+ *
+ * Based on code written by David A Rusling (david.rusling@reo.mts.dec.com).
+ *
+ * IRQ Code common to all PYXIS core logic chips.
+ */
+
+#include <linux/init.h>
+#include <linux/sched.h>
+#include <linux/irq.h>
+
+#include <asm/io.h>
+#include <asm/core_cia.h>
+
+#include "proto.h"
+#include "irq_impl.h"
+
+
+/* Note mask bit is true for ENABLED irqs.  */
+static unsigned long cached_irq_mask;
+
+static inline void
+pyxis_update_irq_hw(unsigned long mask)
+{
+	*(vulp)PYXIS_INT_MASK = mask;
+	mb();
+	*(vulp)PYXIS_INT_MASK;
+}
+
+static inline void
+pyxis_enable_irq(unsigned int irq)
+{
+	pyxis_update_irq_hw(cached_irq_mask |= 1UL << (irq - 16));
+}
+
+static void
+pyxis_disable_irq(unsigned int irq)
+{
+	pyxis_update_irq_hw(cached_irq_mask &= ~(1UL << (irq - 16)));
+}
+
+static unsigned int
+pyxis_startup_irq(unsigned int irq)
+{
+	pyxis_enable_irq(irq);
+	return 0;
+}
+
+static void
+pyxis_end_irq(unsigned int irq)
+{
+	if (!(irq_desc[irq].status & (IRQ_DISABLED|IRQ_INPROGRESS)))
+		pyxis_enable_irq(irq);
+}
+
+static void
+pyxis_mask_and_ack_irq(unsigned int irq)
+{
+	unsigned long bit = 1UL << (irq - 16);
+	unsigned long mask = cached_irq_mask &= ~bit;
+
+	/* Disable the interrupt.  */
+	*(vulp)PYXIS_INT_MASK = mask;
+	wmb();
+	/* Ack PYXIS PCI interrupt.  */
+	*(vulp)PYXIS_INT_REQ = bit;
+	mb();
+	/* Re-read to force both writes.  */
+	*(vulp)PYXIS_INT_MASK;
+}
+
+static struct hw_interrupt_type pyxis_irq_type = {
+	.typename	= "PYXIS",
+	.startup	= pyxis_startup_irq,
+	.shutdown	= pyxis_disable_irq,
+	.enable		= pyxis_enable_irq,
+	.disable	= pyxis_disable_irq,
+	.ack		= pyxis_mask_and_ack_irq,
+	.end		= pyxis_end_irq,
+};
+
+void 
+pyxis_device_interrupt(unsigned long vector, struct pt_regs *regs)
+{
+	unsigned long pld;
+	unsigned int i;
+
+	/* Read the interrupt summary register of PYXIS */
+	pld = *(vulp)PYXIS_INT_REQ;
+	pld &= cached_irq_mask;
+
+	/*
+	 * Now for every possible bit set, work through them and call
+	 * the appropriate interrupt handler.
+	 */
+	while (pld) {
+		i = ffz(~pld);
+		pld &= pld - 1; /* clear least bit set */
+		if (i == 7)
+			isa_device_interrupt(vector, regs);
+		else
+			handle_irq(16+i, regs);
+	}
+}
+
+void __init
+init_pyxis_irqs(unsigned long ignore_mask)
+{
+	long i;
+
+	*(vulp)PYXIS_INT_MASK = 0;		/* disable all */
+	*(vulp)PYXIS_INT_REQ  = -1;		/* flush all */
+	mb();
+
+	/* Send -INTA pulses to clear any pending interrupts ...*/
+	*(vuip) CIA_IACK_SC;
+
+	for (i = 16; i < 48; ++i) {
+		if ((ignore_mask >> i) & 1)
+			continue;
+		irq_desc[i].status = IRQ_DISABLED | IRQ_LEVEL;
+		irq_desc[i].handler = &pyxis_irq_type;
+	}
+
+	setup_irq(16+7, &isa_cascade_irqaction);
+}