/*
* External interrupt handling for AT32AP CPUs
*
* Copyright (C) 2006 Atmel Corporation
*
* 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/errno.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/platform_device.h>
#include <linux/random.h>
#include <linux/slab.h>
#include <asm/io.h>
/* EIC register offsets */
#define EIC_IER 0x0000
#define EIC_IDR 0x0004
#define EIC_IMR 0x0008
#define EIC_ISR 0x000c
#define EIC_ICR 0x0010
#define EIC_MODE 0x0014
#define EIC_EDGE 0x0018
#define EIC_LEVEL 0x001c
#define EIC_NMIC 0x0024
/* Bitfields in NMIC */
#define EIC_NMIC_ENABLE (1 << 0)
/* Bit manipulation macros */
#define EIC_BIT(name) \
(1 << EIC_##name##_OFFSET)
#define EIC_BF(name,value) \
(((value) & ((1 << EIC_##name##_SIZE) - 1)) \
<< EIC_##name##_OFFSET)
#define EIC_BFEXT(name,value) \
(((value) >> EIC_##name##_OFFSET) \
& ((1 << EIC_##name##_SIZE) - 1))
#define EIC_BFINS(name,value,old) \
(((old) & ~(((1 << EIC_##name##_SIZE) - 1) \
<< EIC_##name##_OFFSET)) \
| EIC_BF(name,value))
/* Register access macros */
#define eic_readl(port,reg) \
__raw_readl((port)->regs + EIC_##reg)
#define eic_writel(port,reg,value) \
__raw_writel((value), (port)->regs + EIC_##reg)
struct eic {
void __iomem *regs;
struct irq_chip *chip;
unsigned int first_irq;
};
static struct eic *nmi_eic;
static bool nmi_enabled;
static void eic_ack_irq(unsigned int irq)
{
struct eic *eic = get_irq_chip_data(irq);
eic_writel(eic, ICR, 1 << (irq - eic->first_irq));
}
static void eic_mask_irq(unsigned int irq)
{
struct eic *eic = get_irq_chip_data(irq);
eic_writel(eic, IDR, 1 << (irq - eic->first_irq));
}
static void eic_mask_ack_irq(unsigned int irq)
{
struct eic *eic = get_irq_chip_data(irq);
eic_writel(eic, ICR, 1 << (irq - eic->first_irq));
eic_writel(eic, IDR, 1 << (irq - eic->first_irq));
}
static void eic_unmask_irq(unsigned int irq)
{
struct eic *eic = get_irq_chip_data(irq);
eic_writel(eic, IER, 1 << (irq - eic->first_irq));
}
static int eic_set_irq_type(unsigned int irq, unsigned int flow_type)
{
struct eic *eic = get_irq_chip_data(irq);
struct irq_desc *desc;
unsigned int i = irq - eic->first_irq;
u32 mode, edge, level;
int ret = 0;
flow_type &= IRQ_TYPE_SENSE_MASK;
if (flow_type == IRQ_TYPE_NONE)
flow_type = IRQ_TYPE_LEVEL_LOW;
desc = &irq_desc[irq];
mode = eic_readl(eic, MODE);
edge = eic_readl(eic, EDGE);
level = eic_readl(eic, LEVEL);
switch (flow_type) {
case IRQ_TYPE_LEVEL_LOW:
mode |= 1 << i;
level &= ~(1 << i);
break;
case IRQ_TYPE_LEVEL_HIGH:
mode |= 1 << i;
level |= 1 << i;
break;
case IRQ_TYPE_EDGE_RISING:
mode &= ~(1 << i);
edge |= 1 << i;
break;
case IRQ_TYPE_EDGE_FALLING:
mode &= ~(1 << i);
edge &= ~(1 << i);
break;
default:
ret = -EINVAL;
break;
}
if (ret == 0) {
eic_writel(eic, MODE, mode);
eic_writel(eic, EDGE, edge);
eic_writel(eic, LEVEL, level);
if (flow_type & (IRQ_TYPE_LEVEL_LOW | IRQ_TYPE_LEVEL_HIGH)) {
flow_type |= IRQ_LEVEL;
__set_irq_handler_unlocked(irq, handle_level_irq);
} else
__set_irq_handler_unlocked(irq, handle_edge_irq);
desc->status &= ~(IRQ_TYPE_SENSE_MASK | IRQ_LEVEL);
desc->status |= flow_type;
}
return ret;
}
static struct irq_chip eic_chip = {
.name = "eic",
.ack = eic_ack_irq,
.mask = eic_mask_irq,
.mask_ack = eic_mask_ack_irq,
.unmask = eic_unmask_irq,
.set_type = eic_set_irq_type,
};
static void demux_eic_irq(unsigned int irq, struct irq_desc *desc)
{
struct eic *eic = desc->handler_data;
unsigned long status, pending;
unsigned int i;
status = eic_readl(eic, ISR);
pending = status & eic_readl(eic, IMR);
while (pending) {
i = fls(pending) - 1;
pending &= ~(1 << i);
generic_handle_irq(i + eic->first_irq);
}
}
int nmi_enable(void)
{
nmi_enabled = true;
if (nmi_eic)
eic_writel(nmi_eic, NMIC, EIC_NMIC_ENABLE);
return 0;
}
void nmi_disable(void)
{
if (nmi_eic)
eic_writel(nmi_eic, NMIC, 0);
nmi_enabled = false;
}
static int __init eic_probe(struct platform_device *pdev)
{
struct eic *eic;
struct resource *regs;
unsigned int i;
unsigned int nr_of_irqs;
unsigned int int_irq;
int ret;
u32 pattern;
regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
int_irq = platform_get_irq(pdev, 0);
if (!regs || !int_irq) {
dev_dbg(&pdev->dev, "missing regs and/or irq resource\n");
return -ENXIO;
}
ret = -ENOMEM;
eic = kzalloc(sizeof(struct eic), GFP_KERNEL);
if (!eic) {
dev_dbg(&pdev->dev, "no memory for eic structure\n");
goto err_kzalloc;
}
eic->first_irq = EIM_IRQ_BASE + 32 * pdev->id;
eic->regs = ioremap(regs->start, regs->end - regs->start + 1);
if (!eic->regs) {
dev_dbg(&pdev->dev, "failed to map regs\n");
goto err_ioremap;
}
/*
* Find out how many interrupt lines that are actually
* implemented in hardware.
*/
eic_writel(eic, IDR, ~0UL);
eic_writel(eic, MODE, ~0UL);
pattern = eic_readl(eic, MODE);
nr_of_irqs = fls(pattern);
/* Trigger on low level unless overridden by driver */
eic_writel(eic, EDGE, 0UL);
eic_writel(eic, LEVEL, 0UL);
eic->chip = &eic_chip;
for (i = 0; i < nr_of_irqs; i++) {
set_irq_chip_and_handler(eic->first_irq + i, &eic_chip,
handle_level_irq);
set_irq_chip_data(eic->first_irq + i, eic);
}
set_irq_chained_handler(int_irq, demux_eic_irq);
set_irq_data(int_irq, eic);
if (pdev->id == 0) {
nmi_eic = eic;
if (nmi_enabled)
/*
* Someone tried to enable NMI before we were
* ready. Do it now.
*/
nmi_enable();
}
dev_info(&pdev->dev,
"External Interrupt Controller at 0x%p, IRQ %u\n",
eic->regs, int_irq);
dev_info(&pdev->dev,
"Handling %u external IRQs, starting with IRQ %u\n",
nr_of_irqs, eic->first_irq);
return 0;
err_ioremap:
kfree(eic);
err_kzalloc:
return ret;
}
static struct platform_driver eic_driver = {
.driver = {
.name = "at32_eic",
},
};
static int __init eic_init(void)
{
return platform_driver_probe(&eic_driver, eic_probe);
}
arch_initcall(eic_init);
