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/*
* 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/interrupt.h>
#include <linux/init.h>
#include <linux/of.h>
#include <linux/ftrace.h>
#include <linux/irq.h>
#include <linux/export.h>
#include <linux/irqdomain.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->hwirq));
}
static void or1k_pic_unmask(struct irq_data *data)
{
mtspr(SPR_PICMR, mfspr(SPR_PICMR) | (1UL << data->hwirq));
}
static void or1k_pic_ack(struct irq_data *data)
{
/* EDGE-triggered interrupts need to be ack'ed in order to clear
* the latch.
* LEVEL-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->hwirq));
#else
WARN(1, "Interrupt handling possibly broken\n");
mtspr(SPR_PICSR, (1UL << data->hwirq));
#endif
}
static void or1k_pic_mask_ack(struct irq_data *data)
{
/* Comments for pic_ack apply here, too */
#ifdef CONFIG_OR1K_1200
mtspr(SPR_PICMR, mfspr(SPR_PICMR) & ~(1UL << data->hwirq));
mtspr(SPR_PICSR, mfspr(SPR_PICSR) & ~(1UL << data->hwirq));
#else
WARN(1, "Interrupt handling possibly broken\n");
mtspr(SPR_PICMR, (1UL << data->hwirq));
mtspr(SPR_PICSR, (1UL << data->hwirq));
#endif
}
#if 0
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);
}
#endif
static struct irq_chip or1k_dev = {
.name = "or1k-PIC",
.irq_unmask = or1k_pic_unmask,
.irq_mask = or1k_pic_mask,
.irq_ack = or1k_pic_ack,
.irq_mask_ack = or1k_pic_mask_ack,
};
static struct irq_domain *root_domain;
static inline int pic_get_irq(int first)
{
int hwirq;
hwirq = ffs(mfspr(SPR_PICSR) >> first);
if (!hwirq)
return NO_IRQ;
else
hwirq = hwirq + first -1;
return irq_find_mapping(root_domain, hwirq);
}
static int or1k_map(struct irq_domain *d, unsigned int irq, irq_hw_number_t hw)
{
irq_set_chip_and_handler_name(irq, &or1k_dev,
handle_level_irq, "level");
irq_set_status_flags(irq, IRQ_LEVEL | IRQ_NOPROBE);
return 0;
}
static const struct irq_domain_ops or1k_irq_domain_ops = {
.xlate = irq_domain_xlate_onecell,
.map = or1k_map,
};
/*
* This sets up the IRQ domain for the PIC built in to the OpenRISC
* 1000 CPU. This is the "root" domain as these are the interrupts
* that directly trigger an exception in the CPU.
*/
static void __init or1k_irq_init(void)
{
struct device_node *intc = NULL;
/* The interrupt controller device node is mandatory */
intc = of_find_compatible_node(NULL, NULL, "opencores,or1k-pic");
BUG_ON(!intc);
/* Disable all interrupts until explicitly requested */
mtspr(SPR_PICMR, (0UL));
root_domain = irq_domain_add_linear(intc, 32,
&or1k_irq_domain_ops, NULL);
}
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);
}
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