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/*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*
* Copyright (C) 1992 Linus Torvalds
* Copyright (C) 1994 - 2000 Ralf Baechle
*/
#include <linux/delay.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/kernel.h>
#include <linux/spinlock.h>
#include <asm/i8259.h>
#include <asm/io.h>
#include <asm/sni.h>
DEFINE_SPINLOCK(pciasic_lock);
static void enable_pciasic_irq(unsigned int irq)
{
unsigned int mask = 1 << (irq - PCIMT_IRQ_INT2);
unsigned long flags;
spin_lock_irqsave(&pciasic_lock, flags);
*(volatile u8 *) PCIMT_IRQSEL |= mask;
spin_unlock_irqrestore(&pciasic_lock, flags);
}
static unsigned int startup_pciasic_irq(unsigned int irq)
{
enable_pciasic_irq(irq);
return 0; /* never anything pending */
}
#define shutdown_pciasic_irq disable_pciasic_irq
void disable_pciasic_irq(unsigned int irq)
{
unsigned int mask = ~(1 << (irq - PCIMT_IRQ_INT2));
unsigned long flags;
spin_lock_irqsave(&pciasic_lock, flags);
*(volatile u8 *) PCIMT_IRQSEL &= mask;
spin_unlock_irqrestore(&pciasic_lock, flags);
}
#define mask_and_ack_pciasic_irq disable_pciasic_irq
static void end_pciasic_irq(unsigned int irq)
{
if (!(irq_desc[irq].status & (IRQ_DISABLED|IRQ_INPROGRESS)))
enable_pciasic_irq(irq);
}
static struct irq_chip pciasic_irq_type = {
.typename = "ASIC-PCI",
.startup = startup_pciasic_irq,
.shutdown = shutdown_pciasic_irq,
.enable = enable_pciasic_irq,
.disable = disable_pciasic_irq,
.ack = mask_and_ack_pciasic_irq,
.end = end_pciasic_irq,
};
/*
* hwint0 should deal with MP agent, ASIC PCI, EISA NMI and debug
* button interrupts. Later ...
*/
static void pciasic_hwint0(struct pt_regs *regs)
{
panic("Received int0 but no handler yet ...");
}
/* This interrupt was used for the com1 console on the first prototypes. */
static void pciasic_hwint2(struct pt_regs *regs)
{
/* I think this shouldn't happen on production machines. */
panic("hwint2 and no handler yet");
}
/* hwint5 is the r4k count / compare interrupt */
static void pciasic_hwint5(struct pt_regs *regs)
{
panic("hwint5 and no handler yet");
}
static unsigned int ls1bit8(unsigned int x)
{
int b = 7, s;
s = 4; if ((x & 0x0f) == 0) s = 0; b -= s; x <<= s;
s = 2; if ((x & 0x30) == 0) s = 0; b -= s; x <<= s;
s = 1; if ((x & 0x40) == 0) s = 0; b -= s;
return b;
}
/*
* hwint 1 deals with EISA and SCSI interrupts,
*
* The EISA_INT bit in CSITPEND is high active, all others are low active.
*/
static void pciasic_hwint1(struct pt_regs *regs)
{
u8 pend = *(volatile char *)PCIMT_CSITPEND;
unsigned long flags;
if (pend & IT_EISA) {
int irq;
/*
* Note: ASIC PCI's builtin interrupt achknowledge feature is
* broken. Using it may result in loss of some or all i8259
* interupts, so don't use PCIMT_INT_ACKNOWLEDGE ...
*/
irq = i8259_irq();
if (unlikely(irq < 0))
return;
do_IRQ(irq, regs);
}
if (!(pend & IT_SCSI)) {
flags = read_c0_status();
clear_c0_status(ST0_IM);
do_IRQ(PCIMT_IRQ_SCSI, regs);
write_c0_status(flags);
}
}
/*
* hwint 3 should deal with the PCI A - D interrupts,
*/
static void pciasic_hwint3(struct pt_regs *regs)
{
u8 pend = *(volatile char *)PCIMT_CSITPEND;
int irq;
pend &= (IT_INTA | IT_INTB | IT_INTC | IT_INTD);
clear_c0_status(IE_IRQ3);
irq = PCIMT_IRQ_INT2 + ls1bit8(pend);
do_IRQ(irq, regs);
set_c0_status(IE_IRQ3);
}
/*
* hwint 4 is used for only the onboard PCnet 32.
*/
static void pciasic_hwint4(struct pt_regs *regs)
{
clear_c0_status(IE_IRQ4);
do_IRQ(PCIMT_IRQ_ETHERNET, regs);
set_c0_status(IE_IRQ4);
}
asmlinkage void plat_irq_dispatch(struct pt_regs *regs)
{
unsigned int pending = read_c0_status() & read_c0_cause();
static unsigned char led_cache;
*(volatile unsigned char *) PCIMT_CSLED = ++led_cache;
if (pending & 0x0800)
pciasic_hwint1(regs);
else if (pending & 0x4000)
pciasic_hwint4(regs);
else if (pending & 0x2000)
pciasic_hwint3(regs);
else if (pending & 0x1000)
pciasic_hwint2(regs);
else if (pending & 0x8000)
pciasic_hwint5(regs);
else if (pending & 0x0400)
pciasic_hwint0(regs);
}
void __init init_pciasic(void)
{
unsigned long flags;
spin_lock_irqsave(&pciasic_lock, flags);
* (volatile u8 *) PCIMT_IRQSEL =
IT_EISA | IT_INTA | IT_INTB | IT_INTC | IT_INTD;
spin_unlock_irqrestore(&pciasic_lock, flags);
}
/*
* On systems with i8259-style interrupt controllers we assume for
* driver compatibility reasons interrupts 0 - 15 to be the i8295
* interrupts even if the hardware uses a different interrupt numbering.
*/
void __init arch_init_irq(void)
{
int i;
init_i8259_irqs(); /* Integrated i8259 */
init_pciasic();
/* Actually we've got more interrupts to handle ... */
for (i = PCIMT_IRQ_INT2; i <= PCIMT_IRQ_ETHERNET; i++) {
irq_desc[i].status = IRQ_DISABLED;
irq_desc[i].action = 0;
irq_desc[i].depth = 1;
irq_desc[i].chip = &pciasic_irq_type;
}
change_c0_status(ST0_IM, IE_IRQ1|IE_IRQ2|IE_IRQ3|IE_IRQ4);
}
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