linux/arch/parisc/kernel/irq.c

355 lines
8.8 KiB
C
Raw Normal View History

/*
* Code to handle x86 style IRQs plus some generic interrupt stuff.
*
* Copyright (C) 1992 Linus Torvalds
* Copyright (C) 1994, 1995, 1996, 1997, 1998 Ralf Baechle
* Copyright (C) 1999 SuSE GmbH (Philipp Rumpf, prumpf@tux.org)
* Copyright (C) 1999-2000 Grant Grundler
* Copyright (c) 2005 Matthew Wilcox
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2, or (at your option)
* any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include <linux/bitops.h>
#include <linux/config.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/kernel_stat.h>
#include <linux/seq_file.h>
#include <linux/spinlock.h>
#include <linux/types.h>
#include <asm/smp.h>
#undef PARISC_IRQ_CR16_COUNTS
extern irqreturn_t timer_interrupt(int, void *, struct pt_regs *);
extern irqreturn_t ipi_interrupt(int, void *, struct pt_regs *);
#define EIEM_MASK(irq) (1UL<<(CPU_IRQ_MAX - irq))
/* Bits in EIEM correlate with cpu_irq_action[].
** Numbered *Big Endian*! (ie bit 0 is MSB)
*/
static volatile unsigned long cpu_eiem = 0;
static void cpu_disable_irq(unsigned int irq)
{
unsigned long eirr_bit = EIEM_MASK(irq);
cpu_eiem &= ~eirr_bit;
/* Do nothing on the other CPUs. If they get this interrupt,
* The & cpu_eiem in the do_cpu_irq_mask() ensures they won't
* handle it, and the set_eiem() at the bottom will ensure it
* then gets disabled */
}
static void cpu_enable_irq(unsigned int irq)
{
unsigned long eirr_bit = EIEM_MASK(irq);
cpu_eiem |= eirr_bit;
/* FIXME: while our interrupts aren't nested, we cannot reset
* the eiem mask if we're already in an interrupt. Once we
* implement nested interrupts, this can go away
*/
if (!in_interrupt())
set_eiem(cpu_eiem);
/* This is just a simple NOP IPI. But what it does is cause
* all the other CPUs to do a set_eiem(cpu_eiem) at the end
* of the interrupt handler */
smp_send_all_nop();
}
static unsigned int cpu_startup_irq(unsigned int irq)
{
cpu_enable_irq(irq);
return 0;
}
void no_ack_irq(unsigned int irq) { }
void no_end_irq(unsigned int irq) { }
static struct hw_interrupt_type cpu_interrupt_type = {
.typename = "CPU",
.startup = cpu_startup_irq,
.shutdown = cpu_disable_irq,
.enable = cpu_enable_irq,
.disable = cpu_disable_irq,
.ack = no_ack_irq,
.end = no_end_irq,
// .set_affinity = cpu_set_affinity_irq,
};
int show_interrupts(struct seq_file *p, void *v)
{
int i = *(loff_t *) v, j;
unsigned long flags;
if (i == 0) {
seq_puts(p, " ");
for_each_online_cpu(j)
seq_printf(p, " CPU%d", j);
#ifdef PARISC_IRQ_CR16_COUNTS
seq_printf(p, " [min/avg/max] (CPU cycle counts)");
#endif
seq_putc(p, '\n');
}
if (i < NR_IRQS) {
struct irqaction *action;
spin_lock_irqsave(&irq_desc[i].lock, flags);
action = irq_desc[i].action;
if (!action)
goto skip;
seq_printf(p, "%3d: ", i);
#ifdef CONFIG_SMP
for_each_online_cpu(j)
seq_printf(p, "%10u ", kstat_cpu(j).irqs[i]);
#else
seq_printf(p, "%10u ", kstat_irqs(i));
#endif
seq_printf(p, " %14s", irq_desc[i].handler->typename);
#ifndef PARISC_IRQ_CR16_COUNTS
seq_printf(p, " %s", action->name);
while ((action = action->next))
seq_printf(p, ", %s", action->name);
#else
for ( ;action; action = action->next) {
unsigned int k, avg, min, max;
min = max = action->cr16_hist[0];
for (avg = k = 0; k < PARISC_CR16_HIST_SIZE; k++) {
int hist = action->cr16_hist[k];
if (hist) {
avg += hist;
} else
break;
if (hist > max) max = hist;
if (hist < min) min = hist;
}
avg /= k;
seq_printf(p, " %s[%d/%d/%d]", action->name,
min,avg,max);
}
#endif
seq_putc(p, '\n');
skip:
spin_unlock_irqrestore(&irq_desc[i].lock, flags);
}
return 0;
}
/*
** The following form a "set": Virtual IRQ, Transaction Address, Trans Data.
** Respectively, these map to IRQ region+EIRR, Processor HPA, EIRR bit.
**
** To use txn_XXX() interfaces, get a Virtual IRQ first.
** Then use that to get the Transaction address and data.
*/
int cpu_claim_irq(unsigned int irq, struct hw_interrupt_type *type, void *data)
{
if (irq_desc[irq].action)
return -EBUSY;
if (irq_desc[irq].handler != &cpu_interrupt_type)
return -EBUSY;
if (type) {
irq_desc[irq].handler = type;
irq_desc[irq].handler_data = data;
cpu_interrupt_type.enable(irq);
}
return 0;
}
int txn_claim_irq(int irq)
{
return cpu_claim_irq(irq, NULL, NULL) ? -1 : irq;
}
/*
* The bits_wide parameter accommodates the limitations of the HW/SW which
* use these bits:
* Legacy PA I/O (GSC/NIO): 5 bits (architected EIM register)
* V-class (EPIC): 6 bits
* N/L/A-class (iosapic): 8 bits
* PCI 2.2 MSI: 16 bits
* Some PCI devices: 32 bits (Symbios SCSI/ATM/HyperFabric)
*
* On the service provider side:
* o PA 1.1 (and PA2.0 narrow mode) 5-bits (width of EIR register)
* o PA 2.0 wide mode 6-bits (per processor)
* o IA64 8-bits (0-256 total)
*
* So a Legacy PA I/O device on a PA 2.0 box can't use all the bits supported
* by the processor...and the N/L-class I/O subsystem supports more bits than
* PA2.0 has. The first case is the problem.
*/
int txn_alloc_irq(unsigned int bits_wide)
{
int irq;
/* never return irq 0 cause that's the interval timer */
for (irq = CPU_IRQ_BASE + 1; irq <= CPU_IRQ_MAX; irq++) {
if (cpu_claim_irq(irq, NULL, NULL) < 0)
continue;
if ((irq - CPU_IRQ_BASE) >= (1 << bits_wide))
continue;
return irq;
}
/* unlikely, but be prepared */
return -1;
}
unsigned long txn_alloc_addr(unsigned int virt_irq)
{
static int next_cpu = -1;
next_cpu++; /* assign to "next" CPU we want this bugger on */
/* validate entry */
while ((next_cpu < NR_CPUS) && (!cpu_data[next_cpu].txn_addr ||
!cpu_online(next_cpu)))
next_cpu++;
if (next_cpu >= NR_CPUS)
next_cpu = 0; /* nothing else, assign monarch */
return cpu_data[next_cpu].txn_addr;
}
unsigned int txn_alloc_data(unsigned int virt_irq)
{
return virt_irq - CPU_IRQ_BASE;
}
/* ONLY called from entry.S:intr_extint() */
void do_cpu_irq_mask(struct pt_regs *regs)
{
unsigned long eirr_val;
irq_enter();
/*
[PARISC] Disable nesting of interrupts Disable nesting of interrupts - still has holes The offending sequence starts out like this: 1) take external interrupt 2) set_eiem() to only allow TIMER_IRQ; local interrupts still disabled 3) read the EIRR to get a "list" of pending interrupts 4) clear EIRR of pending interrupts we intend to handle 5) call __do_IRQ() to handle IRQ. 6) handle_IRQ_event() enables local interrupts (I-Bit) 7) take a timer interrupt 8) read EIRR to get a new list of pending interrupts 9) clear EIRR of pending interrupts we just read 10) handle pending interrupts found in (8) 11) set_eiem(cpu_eiem) and return [ TROUBLE! all enabled CPU IRQs are unmasked. } 12) handle remaining interrupts pending from (3) e.g. call __do_IRQ() -> handle_IRQ_event()..etc [ TROUBLE! call to handle_IRQ_event() can now enable *any* IRQ. } 13) set_eiem(cpu_eiem) and return The problem is we now get into ugly race conditions with Timer and IPI interrupts at this point. I'm not exactly sure what happens when things go wrong (perhaps nest calls to IPI or timer interrupt?). But I'm certain it's not good. This sequence will break sooner if (10) would accidentally leave interrupts enabled. I'm pretty sure the right answer is now to make cpu_eiem a per CPU variable since all external interrupts on parisc are per CPU. This means we will NOT need to send an IPI to every CPU in the system when enabling or disabling an IRQ since only one CPU needs to change it's EIEM. Thanks to James Bottomley for (once again) pointing out the problem. Signed-off-by: Grant Grundler <grundler@parisc-linux.org> Signed-off-by: Kyle McMartin <kyle@parisc-linux.org>
2005-11-17 21:26:20 +00:00
* Don't allow TIMER or IPI nested interrupts.
* Allowing any single interrupt to nest can lead to that CPU
* handling interrupts with all enabled interrupts unmasked.
*/
[PARISC] Disable nesting of interrupts Disable nesting of interrupts - still has holes The offending sequence starts out like this: 1) take external interrupt 2) set_eiem() to only allow TIMER_IRQ; local interrupts still disabled 3) read the EIRR to get a "list" of pending interrupts 4) clear EIRR of pending interrupts we intend to handle 5) call __do_IRQ() to handle IRQ. 6) handle_IRQ_event() enables local interrupts (I-Bit) 7) take a timer interrupt 8) read EIRR to get a new list of pending interrupts 9) clear EIRR of pending interrupts we just read 10) handle pending interrupts found in (8) 11) set_eiem(cpu_eiem) and return [ TROUBLE! all enabled CPU IRQs are unmasked. } 12) handle remaining interrupts pending from (3) e.g. call __do_IRQ() -> handle_IRQ_event()..etc [ TROUBLE! call to handle_IRQ_event() can now enable *any* IRQ. } 13) set_eiem(cpu_eiem) and return The problem is we now get into ugly race conditions with Timer and IPI interrupts at this point. I'm not exactly sure what happens when things go wrong (perhaps nest calls to IPI or timer interrupt?). But I'm certain it's not good. This sequence will break sooner if (10) would accidentally leave interrupts enabled. I'm pretty sure the right answer is now to make cpu_eiem a per CPU variable since all external interrupts on parisc are per CPU. This means we will NOT need to send an IPI to every CPU in the system when enabling or disabling an IRQ since only one CPU needs to change it's EIEM. Thanks to James Bottomley for (once again) pointing out the problem. Signed-off-by: Grant Grundler <grundler@parisc-linux.org> Signed-off-by: Kyle McMartin <kyle@parisc-linux.org>
2005-11-17 21:26:20 +00:00
set_eiem(0UL);
/* 1) only process IRQs that are enabled/unmasked (cpu_eiem)
* 2) We loop here on EIRR contents in order to avoid
* nested interrupts or having to take another interrupt
* when we could have just handled it right away.
*/
for (;;) {
unsigned long bit = (1UL << (BITS_PER_LONG - 1));
unsigned int irq;
eirr_val = mfctl(23) & cpu_eiem;
if (!eirr_val)
break;
mtctl(eirr_val, 23); /* reset bits we are going to process */
/* Work our way from MSb to LSb...same order we alloc EIRs */
for (irq = TIMER_IRQ; eirr_val && bit; bit>>=1, irq++) {
if (!(bit & eirr_val))
continue;
/* clear bit in mask - can exit loop sooner */
eirr_val &= ~bit;
__do_IRQ(irq, regs);
}
}
[PARISC] Disable nesting of interrupts Disable nesting of interrupts - still has holes The offending sequence starts out like this: 1) take external interrupt 2) set_eiem() to only allow TIMER_IRQ; local interrupts still disabled 3) read the EIRR to get a "list" of pending interrupts 4) clear EIRR of pending interrupts we intend to handle 5) call __do_IRQ() to handle IRQ. 6) handle_IRQ_event() enables local interrupts (I-Bit) 7) take a timer interrupt 8) read EIRR to get a new list of pending interrupts 9) clear EIRR of pending interrupts we just read 10) handle pending interrupts found in (8) 11) set_eiem(cpu_eiem) and return [ TROUBLE! all enabled CPU IRQs are unmasked. } 12) handle remaining interrupts pending from (3) e.g. call __do_IRQ() -> handle_IRQ_event()..etc [ TROUBLE! call to handle_IRQ_event() can now enable *any* IRQ. } 13) set_eiem(cpu_eiem) and return The problem is we now get into ugly race conditions with Timer and IPI interrupts at this point. I'm not exactly sure what happens when things go wrong (perhaps nest calls to IPI or timer interrupt?). But I'm certain it's not good. This sequence will break sooner if (10) would accidentally leave interrupts enabled. I'm pretty sure the right answer is now to make cpu_eiem a per CPU variable since all external interrupts on parisc are per CPU. This means we will NOT need to send an IPI to every CPU in the system when enabling or disabling an IRQ since only one CPU needs to change it's EIEM. Thanks to James Bottomley for (once again) pointing out the problem. Signed-off-by: Grant Grundler <grundler@parisc-linux.org> Signed-off-by: Kyle McMartin <kyle@parisc-linux.org>
2005-11-17 21:26:20 +00:00
set_eiem(cpu_eiem); /* restore original mask */
irq_exit();
}
static struct irqaction timer_action = {
.handler = timer_interrupt,
.name = "timer",
.flags = SA_INTERRUPT,
};
#ifdef CONFIG_SMP
static struct irqaction ipi_action = {
.handler = ipi_interrupt,
.name = "IPI",
.flags = SA_INTERRUPT,
};
#endif
static void claim_cpu_irqs(void)
{
int i;
for (i = CPU_IRQ_BASE; i <= CPU_IRQ_MAX; i++) {
irq_desc[i].handler = &cpu_interrupt_type;
}
irq_desc[TIMER_IRQ].action = &timer_action;
irq_desc[TIMER_IRQ].status |= IRQ_PER_CPU;
#ifdef CONFIG_SMP
irq_desc[IPI_IRQ].action = &ipi_action;
irq_desc[IPI_IRQ].status = IRQ_PER_CPU;
#endif
}
void __init init_IRQ(void)
{
local_irq_disable(); /* PARANOID - should already be disabled */
mtctl(~0UL, 23); /* EIRR : clear all pending external intr */
claim_cpu_irqs();
#ifdef CONFIG_SMP
if (!cpu_eiem)
cpu_eiem = EIEM_MASK(IPI_IRQ) | EIEM_MASK(TIMER_IRQ);
#else
cpu_eiem = EIEM_MASK(TIMER_IRQ);
#endif
set_eiem(cpu_eiem); /* EIEM : enable all external intr */
}
void hw_resend_irq(struct hw_interrupt_type *type, unsigned int irq)
{
/* XXX: Needs to be written. We managed without it so far, but
* we really ought to write it.
*/
}
void ack_bad_irq(unsigned int irq)
{
printk("unexpected IRQ %d\n", irq);
}