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x86, VisWS: turn into generic arch, clean up

merge traps_visws.c and apic_visws.c into visws_quirks.c.

(no code changed)

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Ingo Molnar 17 lat temu
rodzic
commit
26dd9fcfc2

+ 1 - 1
arch/x86/kernel/Makefile

@@ -19,7 +19,7 @@ obj-y			:= process_$(BITS).o signal_$(BITS).o entry_$(BITS).o
 obj-y			+= traps_$(BITS).o irq_$(BITS).o
 obj-y			+= time_$(BITS).o ioport.o ldt.o
 obj-y			+= setup.o i8259.o irqinit_$(BITS).o setup_percpu.o
-obj-$(CONFIG_X86_VISWS)	+= visws_quirks.o traps_visws.o apic_visws.o
+obj-$(CONFIG_X86_VISWS)	+= visws_quirks.o
 obj-$(CONFIG_X86_32)	+= probe_roms_32.o
 obj-$(CONFIG_X86_32)	+= sys_i386_32.o i386_ksyms_32.o
 obj-$(CONFIG_X86_64)	+= sys_x86_64.o x8664_ksyms_64.o

+ 0 - 295
arch/x86/kernel/apic_visws.c

@@ -1,295 +0,0 @@
-/*
- *	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/kernel_stat.h>
-#include <linux/interrupt.h>
-#include <linux/init.h>
-
-#include <asm/io.h>
-#include <asm/apic.h>
-#include <asm/i8259.h>
-#include <asm/irq_vectors.h>
-#include <asm/visws/cobalt.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 irq_chip 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 irq_chip piix4_master_irq_type = {
-	.typename =	"PIIX4-master",
-	.startup =	startup_piix4_master_irq,
-	.ack =		ack_cobalt_irq,
-	.end =		end_piix4_master_irq,
-};
-
-
-static struct irq_chip piix4_virtual_irq_type = {
-	.typename =	"PIIX4-virtual",
-	.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)
-{
-	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, 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].chip = &cobalt_irq_type;
-		}
-		else if (i == CO_IRQ_IDE0) {
-			irq_desc[i].chip = &cobalt_irq_type;
-		}
-		else if (i == CO_IRQ_IDE1) {
-			irq_desc[i].chip = &cobalt_irq_type;
-		}
-		else if (i == CO_IRQ_8259) {
-			irq_desc[i].chip = &piix4_master_irq_type;
-		}
-		else if (i < CO_IRQ_APIC0) {
-			irq_desc[i].chip = &piix4_virtual_irq_type;
-		}
-		else if (IS_CO_APIC(i)) {
-			irq_desc[i].chip = &cobalt_irq_type;
-		}
-	}
-
-	setup_irq(CO_IRQ_8259, &master_action);
-	setup_irq(2, &cascade_action);
-}

+ 0 - 71
arch/x86/kernel/traps_visws.c

@@ -1,71 +0,0 @@
-/* VISWS traps */
-
-#include <linux/sched.h>
-#include <linux/kernel.h>
-#include <linux/init.h>
-#include <linux/pci.h>
-#include <linux/pci_ids.h>
-
-#include <asm/io.h>
-#include <asm/apic.h>
-#include <asm/arch_hooks.h>
-#include <asm/visws/cobalt.h>
-#include <asm/visws/lithium.h>
-
-
-#define A01234 (LI_INTA_0 | LI_INTA_1 | LI_INTA_2 | LI_INTA_3 | LI_INTA_4)
-#define BCD (LI_INTB | LI_INTC | LI_INTD)
-#define ALLDEVS (A01234 | BCD)
-
-static __init void lithium_init(void)
-{
-	set_fixmap(FIX_LI_PCIA, LI_PCI_A_PHYS);
-	set_fixmap(FIX_LI_PCIB, LI_PCI_B_PHYS);
-
-	if ((li_pcia_read16(PCI_VENDOR_ID) != PCI_VENDOR_ID_SGI) ||
-	    (li_pcia_read16(PCI_DEVICE_ID) != PCI_DEVICE_ID_SGI_LITHIUM)) {
-		printk(KERN_EMERG "Lithium hostbridge %c not found\n", 'A');
-/*		panic("This machine is not SGI Visual Workstation 320/540"); */
-	}
-
-	if ((li_pcib_read16(PCI_VENDOR_ID) != PCI_VENDOR_ID_SGI) ||
-	    (li_pcib_read16(PCI_DEVICE_ID) != PCI_DEVICE_ID_SGI_LITHIUM)) {
-		printk(KERN_EMERG "Lithium hostbridge %c not found\n", 'B');
-/*		panic("This machine is not SGI Visual Workstation 320/540"); */
-	}
-
-	li_pcia_write16(LI_PCI_INTEN, ALLDEVS);
-	li_pcib_write16(LI_PCI_INTEN, ALLDEVS);
-}
-
-static __init void cobalt_init(void)
-{
-	/*
-	 * On normal SMP PC this is used only with SMP, but we have to
-	 * use it and set it up here to start the Cobalt clock
-	 */
-	set_fixmap(FIX_APIC_BASE, APIC_DEFAULT_PHYS_BASE);
-	setup_local_APIC();
-	printk(KERN_INFO "Local APIC Version %#x, ID %#x\n",
-		(unsigned int)apic_read(APIC_LVR),
-		(unsigned int)apic_read(APIC_ID));
-
-	set_fixmap(FIX_CO_CPU, CO_CPU_PHYS);
-	set_fixmap(FIX_CO_APIC, CO_APIC_PHYS);
-	printk(KERN_INFO "Cobalt Revision %#lx, APIC ID %#lx\n",
-		co_cpu_read(CO_CPU_REV), co_apic_read(CO_APIC_ID));
-
-	/* Enable Cobalt APIC being careful to NOT change the ID! */
-	co_apic_write(CO_APIC_ID, co_apic_read(CO_APIC_ID) | CO_APIC_ENABLE);
-
-	printk(KERN_INFO "Cobalt APIC enabled: ID reg %#lx\n",
-		co_apic_read(CO_APIC_ID));
-}
-
-int __init visws_trap_init_quirk(void)
-{
-	lithium_init();
-	cobalt_init();
-
-	return 1;
-}

+ 371 - 2
arch/x86/kernel/visws_quirks.c

@@ -1,8 +1,22 @@
 /*
- *  Unmaintained SGI Visual Workstation support.
+ *  SGI Visual Workstation support and quirks, unmaintained.
+ *
  *  Split out from setup.c by davej@suse.de
+ *
+ *	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/interrupt.h>
 #include <linux/module.h>
 #include <linux/init.h>
@@ -25,6 +39,30 @@
 #include <linux/init.h>
 #include <linux/smp.h>
 
+#include <linux/kernel_stat.h>
+#include <linux/interrupt.h>
+#include <linux/init.h>
+
+#include <asm/io.h>
+#include <asm/apic.h>
+#include <asm/i8259.h>
+#include <asm/irq_vectors.h>
+#include <asm/visws/cobalt.h>
+#include <asm/visws/lithium.h>
+#include <asm/visws/piix4.h>
+
+#include <linux/sched.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/pci.h>
+#include <linux/pci_ids.h>
+
+#include <asm/io.h>
+#include <asm/apic.h>
+#include <asm/arch_hooks.h>
+#include <asm/visws/cobalt.h>
+#include <asm/visws/lithium.h>
+
 char visws_board_type	= -1;
 char visws_board_rev	= -1;
 
@@ -336,3 +374,334 @@ void __init visws_early_detect(void)
 	       (visws_board_type == VISWS_540 ? "540" :
 		"unknown")), visws_board_rev);
 }
+
+#define A01234 (LI_INTA_0 | LI_INTA_1 | LI_INTA_2 | LI_INTA_3 | LI_INTA_4)
+#define BCD (LI_INTB | LI_INTC | LI_INTD)
+#define ALLDEVS (A01234 | BCD)
+
+static __init void lithium_init(void)
+{
+	set_fixmap(FIX_LI_PCIA, LI_PCI_A_PHYS);
+	set_fixmap(FIX_LI_PCIB, LI_PCI_B_PHYS);
+
+	if ((li_pcia_read16(PCI_VENDOR_ID) != PCI_VENDOR_ID_SGI) ||
+	    (li_pcia_read16(PCI_DEVICE_ID) != PCI_DEVICE_ID_SGI_LITHIUM)) {
+		printk(KERN_EMERG "Lithium hostbridge %c not found\n", 'A');
+/*		panic("This machine is not SGI Visual Workstation 320/540"); */
+	}
+
+	if ((li_pcib_read16(PCI_VENDOR_ID) != PCI_VENDOR_ID_SGI) ||
+	    (li_pcib_read16(PCI_DEVICE_ID) != PCI_DEVICE_ID_SGI_LITHIUM)) {
+		printk(KERN_EMERG "Lithium hostbridge %c not found\n", 'B');
+/*		panic("This machine is not SGI Visual Workstation 320/540"); */
+	}
+
+	li_pcia_write16(LI_PCI_INTEN, ALLDEVS);
+	li_pcib_write16(LI_PCI_INTEN, ALLDEVS);
+}
+
+static __init void cobalt_init(void)
+{
+	/*
+	 * On normal SMP PC this is used only with SMP, but we have to
+	 * use it and set it up here to start the Cobalt clock
+	 */
+	set_fixmap(FIX_APIC_BASE, APIC_DEFAULT_PHYS_BASE);
+	setup_local_APIC();
+	printk(KERN_INFO "Local APIC Version %#x, ID %#x\n",
+		(unsigned int)apic_read(APIC_LVR),
+		(unsigned int)apic_read(APIC_ID));
+
+	set_fixmap(FIX_CO_CPU, CO_CPU_PHYS);
+	set_fixmap(FIX_CO_APIC, CO_APIC_PHYS);
+	printk(KERN_INFO "Cobalt Revision %#lx, APIC ID %#lx\n",
+		co_cpu_read(CO_CPU_REV), co_apic_read(CO_APIC_ID));
+
+	/* Enable Cobalt APIC being careful to NOT change the ID! */
+	co_apic_write(CO_APIC_ID, co_apic_read(CO_APIC_ID) | CO_APIC_ENABLE);
+
+	printk(KERN_INFO "Cobalt APIC enabled: ID reg %#lx\n",
+		co_apic_read(CO_APIC_ID));
+}
+
+int __init visws_trap_init_quirk(void)
+{
+	lithium_init();
+	cobalt_init();
+
+	return 1;
+}
+
+/*
+ * IRQ controller / APIC support:
+ */
+
+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 irq_chip 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 irq_chip piix4_master_irq_type = {
+	.typename =	"PIIX4-master",
+	.startup =	startup_piix4_master_irq,
+	.ack =		ack_cobalt_irq,
+	.end =		end_piix4_master_irq,
+};
+
+
+static struct irq_chip piix4_virtual_irq_type = {
+	.typename =	"PIIX4-virtual",
+	.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)
+{
+	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, 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].chip = &cobalt_irq_type;
+		}
+		else if (i == CO_IRQ_IDE0) {
+			irq_desc[i].chip = &cobalt_irq_type;
+		}
+		else if (i == CO_IRQ_IDE1) {
+			irq_desc[i].chip = &cobalt_irq_type;
+		}
+		else if (i == CO_IRQ_8259) {
+			irq_desc[i].chip = &piix4_master_irq_type;
+		}
+		else if (i < CO_IRQ_APIC0) {
+			irq_desc[i].chip = &piix4_virtual_irq_type;
+		}
+		else if (IS_CO_APIC(i)) {
+			irq_desc[i].chip = &cobalt_irq_type;
+		}
+	}
+
+	setup_irq(CO_IRQ_8259, &master_action);
+	setup_irq(2, &cascade_action);
+}