linux/arch/arm/mach-s5pv310/irq-combiner.c
Changhwan Youn 0c0f909689 ARM: S5PV310: Optimize interrupt source searching code
It is reported by Junseok Jung that using clz instruction is
better instead of using for-loop to find the interrupt source.
This patch modifies interrupt source searching code using __ffs().
The __ffs() is implemented using clz instruction.

Suggested-by: Junseok Jung <jundols.jung@samsung.com>
Signed-off-by: Changhwan Youn <chaos.youn@samsung.com>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>
2010-10-21 07:52:18 +09:00

122 lines
2.9 KiB
C

/* linux/arch/arm/mach-s5pv310/irq-combiner.c
*
* Copyright (c) 2010 Samsung Electronics Co., Ltd.
* http://www.samsung.com
*
* Based on arch/arm/common/gic.c
*
* IRQ COMBINER support
*
* 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/io.h>
#include <asm/mach/irq.h>
#define COMBINER_ENABLE_SET 0x0
#define COMBINER_ENABLE_CLEAR 0x4
#define COMBINER_INT_STATUS 0xC
static DEFINE_SPINLOCK(irq_controller_lock);
struct combiner_chip_data {
unsigned int irq_offset;
void __iomem *base;
};
static struct combiner_chip_data combiner_data[MAX_COMBINER_NR];
static inline void __iomem *combiner_base(unsigned int irq)
{
struct combiner_chip_data *combiner_data = get_irq_chip_data(irq);
return combiner_data->base;
}
static void combiner_mask_irq(unsigned int irq)
{
u32 mask = 1 << (irq % 32);
__raw_writel(mask, combiner_base(irq) + COMBINER_ENABLE_CLEAR);
}
static void combiner_unmask_irq(unsigned int irq)
{
u32 mask = 1 << (irq % 32);
__raw_writel(mask, combiner_base(irq) + COMBINER_ENABLE_SET);
}
static void combiner_handle_cascade_irq(unsigned int irq, struct irq_desc *desc)
{
struct combiner_chip_data *chip_data = get_irq_data(irq);
struct irq_chip *chip = get_irq_chip(irq);
unsigned int cascade_irq, combiner_irq;
unsigned long status;
/* primary controller ack'ing */
chip->ack(irq);
spin_lock(&irq_controller_lock);
status = __raw_readl(chip_data->base + COMBINER_INT_STATUS);
spin_unlock(&irq_controller_lock);
if (status == 0)
goto out;
combiner_irq = __ffs(status);
cascade_irq = combiner_irq + (chip_data->irq_offset & ~31);
if (unlikely(cascade_irq >= NR_IRQS))
do_bad_IRQ(cascade_irq, desc);
else
generic_handle_irq(cascade_irq);
out:
/* primary controller unmasking */
chip->unmask(irq);
}
static struct irq_chip combiner_chip = {
.name = "COMBINER",
.mask = combiner_mask_irq,
.unmask = combiner_unmask_irq,
};
void __init combiner_cascade_irq(unsigned int combiner_nr, unsigned int irq)
{
if (combiner_nr >= MAX_COMBINER_NR)
BUG();
if (set_irq_data(irq, &combiner_data[combiner_nr]) != 0)
BUG();
set_irq_chained_handler(irq, combiner_handle_cascade_irq);
}
void __init combiner_init(unsigned int combiner_nr, void __iomem *base,
unsigned int irq_start)
{
unsigned int i;
if (combiner_nr >= MAX_COMBINER_NR)
BUG();
combiner_data[combiner_nr].base = base;
combiner_data[combiner_nr].irq_offset = irq_start;
/* Disable all interrupts */
__raw_writel(0xffffffff, base + COMBINER_ENABLE_CLEAR);
/* Setup the Linux IRQ subsystem */
for (i = irq_start; i < combiner_data[combiner_nr].irq_offset
+ MAX_IRQ_IN_COMBINER; i++) {
set_irq_chip(i, &combiner_chip);
set_irq_chip_data(i, &combiner_data[combiner_nr]);
set_irq_handler(i, handle_level_irq);
set_irq_flags(i, IRQF_VALID | IRQF_PROBE);
}
}