linux/arch/arc/kernel/irq.c
Vineet Gupta bacdf4809a ARC: Interrupt Handling
This contains:
-bootup arch IRQ init: init_IRQ(), arc_init_IRQ()
-generic IRQ subsystem glue: arch_do_IRQ()
-basic IRQ chip setup for in-core intc

Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
2013-02-11 20:00:37 +05:30

136 lines
2.9 KiB
C

/*
* Copyright (C) 2011-12 Synopsys, Inc. (www.synopsys.com)
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
*/
#include <linux/interrupt.h>
#include <linux/module.h>
#include <asm/sections.h>
#include <asm/irq.h>
/*
* Early Hardware specific Interrupt setup
* -Called very early (start_kernel -> setup_arch -> setup_processor)
* -Platform Independent (must for any ARC700)
* -Needed for each CPU (hence not foldable into init_IRQ)
*
* what it does ?
* -setup Vector Table Base Reg - in case Linux not linked at 0x8000_0000
* -Disable all IRQs (on CPU side)
*/
void __init arc_init_IRQ(void)
{
int level_mask = level_mask;
write_aux_reg(AUX_INTR_VEC_BASE, _int_vec_base_lds);
/* Disable all IRQs: enable them as devices request */
write_aux_reg(AUX_IENABLE, 0);
}
/*
* ARC700 core includes a simple on-chip intc supporting
* -per IRQ enable/disable
* -2 levels of interrupts (high/low)
* -all interrupts being level triggered
*
* To reduce platform code, we assume all IRQs directly hooked-up into intc.
* Platforms with external intc, hence cascaded IRQs, are free to over-ride
* below, per IRQ.
*/
static void arc_mask_irq(struct irq_data *data)
{
arch_mask_irq(data->irq);
}
static void arc_unmask_irq(struct irq_data *data)
{
arch_unmask_irq(data->irq);
}
static struct irq_chip onchip_intc = {
.name = "ARC In-core Intc",
.irq_mask = arc_mask_irq,
.irq_unmask = arc_unmask_irq,
};
void __init init_onchip_IRQ(void)
{
int i;
for (i = 0; i < NR_IRQS; i++)
irq_set_chip_and_handler(i, &onchip_intc, handle_level_irq);
#ifdef CONFIG_SMP
irq_set_chip_and_handler(TIMER0_IRQ, &onchip_intc, handle_percpu_irq);
#endif
}
/*
* Late Interrupt system init called from start_kernel for Boot CPU only
*
* Since slab must already be initialized, platforms can start doing any
* needed request_irq( )s
*/
void __init init_IRQ(void)
{
init_onchip_IRQ();
plat_init_IRQ();
}
/*
* "C" Entry point for any ARC ISR, called from low level vector handler
* @irq is the vector number read from ICAUSE reg of on-chip intc
*/
void arch_do_IRQ(unsigned int irq, struct pt_regs *regs)
{
struct pt_regs *old_regs = set_irq_regs(regs);
irq_enter();
generic_handle_irq(irq);
irq_exit();
set_irq_regs(old_regs);
}
int __init get_hw_config_num_irq(void)
{
uint32_t val = read_aux_reg(ARC_REG_VECBASE_BCR);
switch (val & 0x03) {
case 0:
return 16;
case 1:
return 32;
case 2:
return 8;
default:
return 0;
}
return 0;
}
void arch_local_irq_enable(void)
{
unsigned long flags;
/*
* ARC IDE Drivers tries to re-enable interrupts from hard-isr
* context which is simply wrong
*/
if (in_irq()) {
WARN_ONCE(1, "IRQ enabled from hard-isr");
return;
}
flags = arch_local_save_flags();
flags |= (STATUS_E1_MASK | STATUS_E2_MASK);
arch_local_irq_restore(flags);
}
EXPORT_SYMBOL(arch_local_irq_enable);