/*
* 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 "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 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);
}
