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