1 files changed, 303 insertions, 0 deletions
diff --git a/arch/i386/mach-visws/visws_apic.c b/arch/i386/mach-visws/visws_apic.c
new file mode 100644
index 00000000000..04e6585849a
--- /dev/null
+++ b/arch/i386/mach-visws/visws_apic.c
@@ -0,0 +1,303 @@
+/*
+ *	linux/arch/i386/mach_visws/visws_apic.c
+ *
+ *	Copyright (C) 1999 Bent Hagemark, Ingo Molnar
+ *
+ *  SGI Visual Workstation interrupt controller
+ *
+ *  The Cobalt system ASIC in the Visual Workstation contains a "Cobalt" APIC
+ *  which serves as the main interrupt controller in the system.  Non-legacy
+ *  hardware in the system uses this controller directly.  Legacy devices
+ *  are connected to the PIIX4 which in turn has its 8259(s) connected to
+ *  a of the Cobalt APIC entry.
+ *
+ *  09/02/2000 - Updated for 2.4 by jbarnes@sgi.com
+ *
+ *  25/11/2002 - Updated for 2.5 by Andrey Panin <pazke@orbita1.ru>
+ */
+
+#include <linux/config.h>
+#include <linux/kernel_stat.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/smp_lock.h>
+#include <linux/init.h>
+
+#include <asm/io.h>
+#include <asm/apic.h>
+#include <asm/i8259.h>
+
+#include "cobalt.h"
+#include "irq_vectors.h"
+
+
+static DEFINE_SPINLOCK(cobalt_lock);
+
+/*
+ * Set the given Cobalt APIC Redirection Table entry to point
+ * to the given IDT vector/index.
+ */
+static inline void co_apic_set(int entry, int irq)
+{
+	co_apic_write(CO_APIC_LO(entry), CO_APIC_LEVEL | (irq + FIRST_EXTERNAL_VECTOR));
+	co_apic_write(CO_APIC_HI(entry), 0);
+}
+
+/*
+ * Cobalt (IO)-APIC functions to handle PCI devices.
+ */
+static inline int co_apic_ide0_hack(void)
+{
+	extern char visws_board_type;
+	extern char visws_board_rev;
+
+	if (visws_board_type == VISWS_320 && visws_board_rev == 5)
+		return 5;
+	return CO_APIC_IDE0;
+}
+
+static int is_co_apic(unsigned int irq)
+{
+	if (IS_CO_APIC(irq))
+		return CO_APIC(irq);
+
+	switch (irq) {
+		case 0: return CO_APIC_CPU;
+		case CO_IRQ_IDE0: return co_apic_ide0_hack();
+		case CO_IRQ_IDE1: return CO_APIC_IDE1;
+		default: return -1;
+	}
+}
+
+
+/*
+ * This is the SGI Cobalt (IO-)APIC:
+ */
+
+static void enable_cobalt_irq(unsigned int irq)
+{
+	co_apic_set(is_co_apic(irq), irq);
+}
+
+static void disable_cobalt_irq(unsigned int irq)
+{
+	int entry = is_co_apic(irq);
+
+	co_apic_write(CO_APIC_LO(entry), CO_APIC_MASK);
+	co_apic_read(CO_APIC_LO(entry));
+}
+
+/*
+ * "irq" really just serves to identify the device.  Here is where we
+ * map this to the Cobalt APIC entry where it's physically wired.
+ * This is called via request_irq -> setup_irq -> irq_desc->startup()
+ */
+static unsigned int startup_cobalt_irq(unsigned int irq)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&cobalt_lock, flags);
+	if ((irq_desc[irq].status & (IRQ_DISABLED | IRQ_INPROGRESS | IRQ_WAITING)))
+		irq_desc[irq].status &= ~(IRQ_DISABLED | IRQ_INPROGRESS | IRQ_WAITING);
+	enable_cobalt_irq(irq);
+	spin_unlock_irqrestore(&cobalt_lock, flags);
+	return 0;
+}
+
+static void ack_cobalt_irq(unsigned int irq)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&cobalt_lock, flags);
+	disable_cobalt_irq(irq);
+	apic_write(APIC_EOI, APIC_EIO_ACK);
+	spin_unlock_irqrestore(&cobalt_lock, flags);
+}
+
+static void end_cobalt_irq(unsigned int irq)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&cobalt_lock, flags);
+	if (!(irq_desc[irq].status & (IRQ_DISABLED | IRQ_INPROGRESS)))
+		enable_cobalt_irq(irq);
+	spin_unlock_irqrestore(&cobalt_lock, flags);
+}
+
+static struct hw_interrupt_type cobalt_irq_type = {
+	.typename =	"Cobalt-APIC",
+	.startup =	startup_cobalt_irq,
+	.shutdown =	disable_cobalt_irq,
+	.enable =	enable_cobalt_irq,
+	.disable =	disable_cobalt_irq,
+	.ack =		ack_cobalt_irq,
+	.end =		end_cobalt_irq,
+};
+
+
+/*
+ * This is the PIIX4-based 8259 that is wired up indirectly to Cobalt
+ * -- not the manner expected by the code in i8259.c.
+ *
+ * there is a 'master' physical interrupt source that gets sent to
+ * the CPU. But in the chipset there are various 'virtual' interrupts
+ * waiting to be handled. We represent this to Linux through a 'master'
+ * interrupt controller type, and through a special virtual interrupt-
+ * controller. Device drivers only see the virtual interrupt sources.
+ */
+static unsigned int startup_piix4_master_irq(unsigned int irq)
+{
+	init_8259A(0);
+
+	return startup_cobalt_irq(irq);
+}
+
+static void end_piix4_master_irq(unsigned int irq)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&cobalt_lock, flags);
+	enable_cobalt_irq(irq);
+	spin_unlock_irqrestore(&cobalt_lock, flags);
+}
+
+static struct hw_interrupt_type piix4_master_irq_type = {
+	.typename =	"PIIX4-master",
+	.startup =	startup_piix4_master_irq,
+	.ack =		ack_cobalt_irq,
+	.end =		end_piix4_master_irq,
+};
+
+
+static struct hw_interrupt_type piix4_virtual_irq_type = {
+	.typename =	"PIIX4-virtual",
+	.startup =	startup_8259A_irq,
+	.shutdown =	disable_8259A_irq,
+	.enable =	enable_8259A_irq,
+	.disable =	disable_8259A_irq,
+};
+
+
+/*
+ * PIIX4-8259 master/virtual functions to handle interrupt requests
+ * from legacy devices: floppy, parallel, serial, rtc.
+ *
+ * None of these get Cobalt APIC entries, neither do they have IDT
+ * entries. These interrupts are purely virtual and distributed from
+ * the 'master' interrupt source: CO_IRQ_8259.
+ *
+ * When the 8259 interrupts its handler figures out which of these
+ * devices is interrupting and dispatches to its handler.
+ *
+ * CAREFUL: devices see the 'virtual' interrupt only. Thus disable/
+ * enable_irq gets the right irq. This 'master' irq is never directly
+ * manipulated by any driver.
+ */
+static irqreturn_t piix4_master_intr(int irq, void *dev_id, struct pt_regs * regs)
+{
+	int realirq;
+	irq_desc_t *desc;
+	unsigned long flags;
+
+	spin_lock_irqsave(&i8259A_lock, flags);
+
+	/* Find out what's interrupting in the PIIX4 master 8259 */
+	outb(0x0c, 0x20);		/* OCW3 Poll command */
+	realirq = inb(0x20);
+
+	/*
+	 * Bit 7 == 0 means invalid/spurious
+	 */
+	if (unlikely(!(realirq & 0x80)))
+		goto out_unlock;
+
+	realirq &= 7;
+
+	if (unlikely(realirq == 2)) {
+		outb(0x0c, 0xa0);
+		realirq = inb(0xa0);
+
+		if (unlikely(!(realirq & 0x80)))
+			goto out_unlock;
+
+		realirq = (realirq & 7) + 8;
+	}
+
+	/* mask and ack interrupt */
+	cached_irq_mask |= 1 << realirq;
+	if (unlikely(realirq > 7)) {
+		inb(0xa1);
+		outb(cached_slave_mask, 0xa1);
+		outb(0x60 + (realirq & 7), 0xa0);
+		outb(0x60 + 2, 0x20);
+	} else {
+		inb(0x21);
+		outb(cached_master_mask, 0x21);
+		outb(0x60 + realirq, 0x20);
+	}
+
+	spin_unlock_irqrestore(&i8259A_lock, flags);
+
+	desc = irq_desc + realirq;
+
+	/*
+	 * handle this 'virtual interrupt' as a Cobalt one now.
+	 */
+	kstat_cpu(smp_processor_id()).irqs[realirq]++;
+
+	if (likely(desc->action != NULL))
+		handle_IRQ_event(realirq, regs, desc->action);
+
+	if (!(desc->status & IRQ_DISABLED))
+		enable_8259A_irq(realirq);
+
+	return IRQ_HANDLED;
+
+out_unlock:
+	spin_unlock_irqrestore(&i8259A_lock, flags);
+	return IRQ_NONE;
+}
+
+static struct irqaction master_action = {
+	.handler =	piix4_master_intr,
+	.name =		"PIIX4-8259",
+};
+
+static struct irqaction cascade_action = {
+	.handler = 	no_action,
+	.name =		"cascade",
+};
+
+
+void init_VISWS_APIC_irqs(void)
+{
+	int i;
+
+	for (i = 0; i < CO_IRQ_APIC0 + CO_APIC_LAST + 1; i++) {
+		irq_desc[i].status = IRQ_DISABLED;
+		irq_desc[i].action = 0;
+		irq_desc[i].depth = 1;
+
+		if (i == 0) {
+			irq_desc[i].handler = &cobalt_irq_type;
+		}
+		else if (i == CO_IRQ_IDE0) {
+			irq_desc[i].handler = &cobalt_irq_type;
+		}
+		else if (i == CO_IRQ_IDE1) {
+			irq_desc[i].handler = &cobalt_irq_type;
+		}
+		else if (i == CO_IRQ_8259) {
+			irq_desc[i].handler = &piix4_master_irq_type;
+		}
+		else if (i < CO_IRQ_APIC0) {
+			irq_desc[i].handler = &piix4_virtual_irq_type;
+		}
+		else if (IS_CO_APIC(i)) {
+			irq_desc[i].handler = &cobalt_irq_type;
+		}
+	}
+
+	setup_irq(CO_IRQ_8259, &master_action);
+	setup_irq(2, &cascade_action);
+}