linux/arch/alpha/kernel/irq_i8259.c

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/*
* linux/arch/alpha/kernel/irq_i8259.c
*
* This is the 'legacy' 8259A Programmable Interrupt Controller,
* present in the majority of PC/AT boxes.
*
* Started hacking from linux-2.3.30pre6/arch/i386/kernel/i8259.c.
*/
#include <linux/init.h>
#include <linux/cache.h>
#include <linux/sched.h>
#include <linux/irq.h>
#include <linux/interrupt.h>
#include <asm/io.h>
#include "proto.h"
#include "irq_impl.h"
/* Note mask bit is true for DISABLED irqs. */
static unsigned int cached_irq_mask = 0xffff;
static DEFINE_SPINLOCK(i8259_irq_lock);
static inline void
i8259_update_irq_hw(unsigned int irq, unsigned long mask)
{
int port = 0x21;
if (irq & 8) mask >>= 8;
if (irq & 8) port = 0xA1;
outb(mask, port);
}
inline void
i8259a_enable_irq(unsigned int irq)
{
spin_lock(&i8259_irq_lock);
i8259_update_irq_hw(irq, cached_irq_mask &= ~(1 << irq));
spin_unlock(&i8259_irq_lock);
}
static inline void
__i8259a_disable_irq(unsigned int irq)
{
i8259_update_irq_hw(irq, cached_irq_mask |= 1 << irq);
}
void
i8259a_disable_irq(unsigned int irq)
{
spin_lock(&i8259_irq_lock);
__i8259a_disable_irq(irq);
spin_unlock(&i8259_irq_lock);
}
void
i8259a_mask_and_ack_irq(unsigned int irq)
{
spin_lock(&i8259_irq_lock);
__i8259a_disable_irq(irq);
/* Ack the interrupt making it the lowest priority. */
if (irq >= 8) {
outb(0xE0 | (irq - 8), 0xa0); /* ack the slave */
irq = 2;
}
outb(0xE0 | irq, 0x20); /* ack the master */
spin_unlock(&i8259_irq_lock);
}
unsigned int
i8259a_startup_irq(unsigned int irq)
{
i8259a_enable_irq(irq);
return 0; /* never anything pending */
}
void
i8259a_end_irq(unsigned int irq)
{
if (!(irq_desc[irq].status & (IRQ_DISABLED|IRQ_INPROGRESS)))
i8259a_enable_irq(irq);
}
struct hw_interrupt_type i8259a_irq_type = {
.typename = "XT-PIC",
.startup = i8259a_startup_irq,
.shutdown = i8259a_disable_irq,
.enable = i8259a_enable_irq,
.disable = i8259a_disable_irq,
.ack = i8259a_mask_and_ack_irq,
.end = i8259a_end_irq,
};
void __init
init_i8259a_irqs(void)
{
static struct irqaction cascade = {
.handler = no_action,
.name = "cascade",
};
long i;
outb(0xff, 0x21); /* mask all of 8259A-1 */
outb(0xff, 0xA1); /* mask all of 8259A-2 */
for (i = 0; i < 16; i++) {
irq_desc[i].status = IRQ_DISABLED;
[PATCH] genirq: rename desc->handler to desc->chip This patch-queue improves the generic IRQ layer to be truly generic, by adding various abstractions and features to it, without impacting existing functionality. While the queue can be best described as "fix and improve everything in the generic IRQ layer that we could think of", and thus it consists of many smaller features and lots of cleanups, the one feature that stands out most is the new 'irq chip' abstraction. The irq-chip abstraction is about describing and coding and IRQ controller driver by mapping its raw hardware capabilities [and quirks, if needed] in a straightforward way, without having to think about "IRQ flow" (level/edge/etc.) type of details. This stands in contrast with the current 'irq-type' model of genirq architectures, which 'mixes' raw hardware capabilities with 'flow' details. The patchset supports both types of irq controller designs at once, and converts i386 and x86_64 to the new irq-chip design. As a bonus side-effect of the irq-chip approach, chained interrupt controllers (master/slave PIC constructs, etc.) are now supported by design as well. The end result of this patchset intends to be simpler architecture-level code and more consolidation between architectures. We reused many bits of code and many concepts from Russell King's ARM IRQ layer, the merging of which was one of the motivations for this patchset. This patch: rename desc->handler to desc->chip. Originally i did not want to do this, because it's a big patch. But having both "desc->handler", "desc->handle_irq" and "action->handler" caused a large degree of confusion and made the code appear alot less clean than it truly is. I have also attempted a dual approach as well by introducing a desc->chip alias - but that just wasnt robust enough and broke frequently. So lets get over with this quickly. The conversion was done automatically via scripts and converts all the code in the kernel. This renaming patch is the first one amongst the patches, so that the remaining patches can stay flexible and can be merged and split up without having some big monolithic patch act as a merge barrier. [akpm@osdl.org: build fix] [akpm@osdl.org: another build fix] Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-29 09:24:36 +00:00
irq_desc[i].chip = &i8259a_irq_type;
}
setup_irq(2, &cascade);
}
#if defined(CONFIG_ALPHA_GENERIC)
# define IACK_SC alpha_mv.iack_sc
#elif defined(CONFIG_ALPHA_APECS)
# define IACK_SC APECS_IACK_SC
#elif defined(CONFIG_ALPHA_LCA)
# define IACK_SC LCA_IACK_SC
#elif defined(CONFIG_ALPHA_CIA)
# define IACK_SC CIA_IACK_SC
#elif defined(CONFIG_ALPHA_PYXIS)
# define IACK_SC PYXIS_IACK_SC
#elif defined(CONFIG_ALPHA_TITAN)
# define IACK_SC TITAN_IACK_SC
#elif defined(CONFIG_ALPHA_TSUNAMI)
# define IACK_SC TSUNAMI_IACK_SC
#elif defined(CONFIG_ALPHA_IRONGATE)
# define IACK_SC IRONGATE_IACK_SC
#endif
/* Note that CONFIG_ALPHA_POLARIS is intentionally left out here, since
sys_rx164 wants to use isa_no_iack_sc_device_interrupt for some reason. */
#if defined(IACK_SC)
void
isa_device_interrupt(unsigned long vector)
{
/*
* Generate a PCI interrupt acknowledge cycle. The PIC will
* respond with the interrupt vector of the highest priority
* interrupt that is pending. The PALcode sets up the
* interrupts vectors such that irq level L generates vector L.
*/
int j = *(vuip) IACK_SC;
j &= 0xff;
handle_irq(j, get_irq_regs());
}
#endif
#if defined(CONFIG_ALPHA_GENERIC) || !defined(IACK_SC)
void
isa_no_iack_sc_device_interrupt(unsigned long vector, struct pt_regs *regs)
{
unsigned long pic;
/*
* It seems to me that the probability of two or more *device*
* interrupts occurring at almost exactly the same time is
* pretty low. So why pay the price of checking for
* additional interrupts here if the common case can be
* handled so much easier?
*/
/*
* The first read of gives you *all* interrupting lines.
* Therefore, read the mask register and and out those lines
* not enabled. Note that some documentation has 21 and a1
* write only. This is not true.
*/
pic = inb(0x20) | (inb(0xA0) << 8); /* read isr */
pic &= 0xFFFB; /* mask out cascade & hibits */
while (pic) {
int j = ffz(~pic);
pic &= pic - 1;
handle_irq(j, regs);
}
}
#endif