/*
* OpenRISC irq.c
*
* Linux architectural port borrowing liberally from similar works of
* others. All original copyrights apply as per the original source
* declaration.
*
* Modifications for the OpenRISC architecture:
* Copyright (C) 2010-2011 Jonas Bonn <jonas@southpole.se>
*
* 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 of the License, or (at your option) any later version.
*/
#include <linux/ptrace.h>
#include <linux/errno.h>
#include <linux/interrupt.h>
#include <linux/init.h>
#include <linux/of.h>
#include <linux/ftrace.h>
#include <linux/irq.h>
#include <linux/seq_file.h>
#include <linux/kernel_stat.h>
#include <linux/export.h>
#include <linux/irqflags.h>
/* read interrupt enabled status */
unsigned long arch_local_save_flags(void)
{
return mfspr(SPR_SR) & (SPR_SR_IEE|SPR_SR_TEE);
}
EXPORT_SYMBOL(arch_local_save_flags);
/* set interrupt enabled status */
void arch_local_irq_restore(unsigned long flags)
{
mtspr(SPR_SR, ((mfspr(SPR_SR) & ~(SPR_SR_IEE|SPR_SR_TEE)) | flags));
}
EXPORT_SYMBOL(arch_local_irq_restore);
/* OR1K PIC implementation */
/* We're a couple of cycles faster than the generic implementations with
* these 'fast' versions.
*/
static void or1k_pic_mask(struct irq_data *data)
{
mtspr(SPR_PICMR, mfspr(SPR_PICMR) & ~(1UL << data->irq));
}
static void or1k_pic_unmask(struct irq_data *data)
{
mtspr(SPR_PICMR, mfspr(SPR_PICMR) | (1UL << data->irq));
}
static void or1k_pic_ack(struct irq_data *data)
{
/* EDGE-triggered interrupts need to be ack'ed in order to clear
* the latch.
* LEVER-triggered interrupts do not need to be ack'ed; however,
* ack'ing the interrupt has no ill-effect and is quicker than
* trying to figure out what type it is...
*/
/* The OpenRISC 1000 spec says to write a 1 to the bit to ack the
* interrupt, but the OR1200 does this backwards and requires a 0
* to be written...
*/
#ifdef CONFIG_OR1K_1200
/* There are two oddities with the OR1200 PIC implementation:
* i) LEVEL-triggered interrupts are latched and need to be cleared
* ii) the interrupt latch is cleared by writing a 0 to the bit,
* as opposed to a 1 as mandated by the spec
*/
mtspr(SPR_PICSR, mfspr(SPR_PICSR) & ~(1UL << data->irq));
#else
WARN(1, "Interrupt handling possibily broken\n");
mtspr(SPR_PICSR, (1UL << irq));
#endif
}
static void or1k_pic_mask_ack(struct irq_data *data)
{
/* Comments for pic_ack apply here, too */
#ifdef CONFIG_OR1K_1200
mtspr(SPR_PICSR, mfspr(SPR_PICSR) & ~(1UL << data->irq));
#else
WARN(1, "Interrupt handling possibily broken\n");
mtspr(SPR_PICSR, (1UL << irq));
#endif
}
static int or1k_pic_set_type(struct irq_data *data, unsigned int flow_type)
{
/* There's nothing to do in the PIC configuration when changing
* flow type. Level and edge-triggered interrupts are both
* supported, but it's PIC-implementation specific which type
* is handled. */
return irq_setup_alt_chip(data, flow_type);
}
static inline int pic_get_irq(int first)
{
int irq;
irq = ffs(mfspr(SPR_PICSR) >> first);
return irq ? irq + first - 1 : NO_IRQ;
}
static void __init or1k_irq_init(void)
{
struct irq_chip_generic *gc;
struct irq_chip_type *ct;
/* Disable all interrupts until explicitly requested */
mtspr(SPR_PICMR, (0UL));
gc = irq_alloc_generic_chip("or1k-PIC", 1, 0, 0, handle_level_irq);
ct = gc->chip_types;
ct->chip.irq_unmask = or1k_pic_unmask;
ct->chip.irq_mask = or1k_pic_mask;
ct->chip.irq_ack = or1k_pic_ack;
ct->chip.irq_mask_ack = or1k_pic_mask_ack;
ct->chip.irq_set_type = or1k_pic_set_type;
/* The OR1K PIC can handle both level and edge trigged
* interrupts in roughly the same manner
*/
#if 0
/* FIXME: chip.type??? */
ct->chip.type = IRQ_TYPE_EDGE_BOTH | IRQ_TYPE_LEVEL_MASK;
#endif
irq_setup_generic_chip(gc, IRQ_MSK(NR_IRQS), 0,
IRQ_NOREQUEST, IRQ_LEVEL | IRQ_NOPROBE);
}
void __init init_IRQ(void)
{
or1k_irq_init();
}
void __irq_entry do_IRQ(struct pt_regs *regs)
{
int irq = -1;
struct pt_regs *old_regs = set_irq_regs(regs);
irq_enter();
while ((irq = pic_get_irq(irq + 1)) != NO_IRQ)
generic_handle_irq(irq);
irq_exit();
set_irq_regs(old_regs);
}
unsigned int irq_create_of_mapping(struct device_node *controller,
const u32 *intspec, unsigned int intsize)
{
return intspec[0];
}
EXPORT_SYMBOL_GPL(irq_create_of_mapping);
