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/*
* Allwinner A1X SoCs IRQ chip driver.
*
* Copyright (C) 2012 Maxime Ripard
*
* Maxime Ripard <maxime.ripard@free-electrons.com>
*
* Based on code from
* Allwinner Technology Co., Ltd. <www.allwinnertech.com>
* Benn Huang <benn@allwinnertech.com>
*
* This file is licensed under the terms of the GNU General Public
* License version 2. This program is licensed "as is" without any
* warranty of any kind, whether express or implied.
*/
#include <linux/io.h>
#include <linux/irq.h>
#include <linux/irqchip.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/of_irq.h>
#include <asm/exception.h>
#define SUN4I_IRQ_VECTOR_REG 0x00
#define SUN4I_IRQ_PROTECTION_REG 0x08
#define SUN4I_IRQ_NMI_CTRL_REG 0x0c
#define SUN4I_IRQ_PENDING_REG(x) (0x10 + 0x4 * x)
#define SUN4I_IRQ_FIQ_PENDING_REG(x) (0x20 + 0x4 * x)
#define SUN4I_IRQ_ENABLE_REG(x) (0x40 + 0x4 * x)
#define SUN4I_IRQ_MASK_REG(x) (0x50 + 0x4 * x)
static void __iomem *sun4i_irq_base;
static struct irq_domain *sun4i_irq_domain;
static void __exception_irq_entry sun4i_handle_irq(struct pt_regs *regs);
static void sun4i_irq_ack(struct irq_data *irqd)
{
unsigned int irq = irqd_to_hwirq(irqd);
if (irq != 0)
return; /* Only IRQ 0 / the ENMI needs to be acked */
writel(BIT(0), sun4i_irq_base + SUN4I_IRQ_PENDING_REG(0));
}
static void sun4i_irq_mask(struct irq_data *irqd)
{
unsigned int irq = irqd_to_hwirq(irqd);
unsigned int irq_off = irq % 32;
int reg = irq / 32;
u32 val;
val = readl(sun4i_irq_base + SUN4I_IRQ_ENABLE_REG(reg));
writel(val & ~(1 << irq_off),
sun4i_irq_base + SUN4I_IRQ_ENABLE_REG(reg));
}
static void sun4i_irq_unmask(struct irq_data *irqd)
{
unsigned int irq = irqd_to_hwirq(irqd);
unsigned int irq_off = irq % 32;
int reg = irq / 32;
u32 val;
val = readl(sun4i_irq_base + SUN4I_IRQ_ENABLE_REG(reg));
writel(val | (1 << irq_off),
sun4i_irq_base + SUN4I_IRQ_ENABLE_REG(reg));
}
static struct irq_chip sun4i_irq_chip = {
.name = "sun4i_irq",
.irq_eoi = sun4i_irq_ack,
.irq_mask = sun4i_irq_mask,
.irq_unmask = sun4i_irq_unmask,
.flags = IRQCHIP_EOI_THREADED | IRQCHIP_EOI_IF_HANDLED,
};
static int sun4i_irq_map(struct irq_domain *d, unsigned int virq,
irq_hw_number_t hw)
{
irq_set_chip_and_handler(virq, &sun4i_irq_chip, handle_fasteoi_irq);
irq_set_probe(virq);
return 0;
}
static const struct irq_domain_ops sun4i_irq_ops = {
.map = sun4i_irq_map,
.xlate = irq_domain_xlate_onecell,
};
static int __init sun4i_of_init(struct device_node *node,
struct device_node *parent)
{
sun4i_irq_base = of_iomap(node, 0);
if (!sun4i_irq_base)
panic("%pOF: unable to map IC registers\n",
node);
/* Disable all interrupts */
writel(0, sun4i_irq_base + SUN4I_IRQ_ENABLE_REG(0));
writel(0, sun4i_irq_base + SUN4I_IRQ_ENABLE_REG(1));
writel(0, sun4i_irq_base + SUN4I_IRQ_ENABLE_REG(2));
/* Unmask all the interrupts, ENABLE_REG(x) is used for masking */
writel(0, sun4i_irq_base + SUN4I_IRQ_MASK_REG(0));
writel(0, sun4i_irq_base + SUN4I_IRQ_MASK_REG(1));
writel(0, sun4i_irq_base + SUN4I_IRQ_MASK_REG(2));
/* Clear all the pending interrupts */
writel(0xffffffff, sun4i_irq_base + SUN4I_IRQ_PENDING_REG(0));
writel(0xffffffff, sun4i_irq_base + SUN4I_IRQ_PENDING_REG(1));
writel(0xffffffff, sun4i_irq_base + SUN4I_IRQ_PENDING_REG(2));
/* Enable protection mode */
writel(0x01, sun4i_irq_base + SUN4I_IRQ_PROTECTION_REG);
/* Configure the external interrupt source type */
writel(0x00, sun4i_irq_base + SUN4I_IRQ_NMI_CTRL_REG);
sun4i_irq_domain = irq_domain_add_linear(node, 3 * 32,
&sun4i_irq_ops, NULL);
if (!sun4i_irq_domain)
panic("%pOF: unable to create IRQ domain\n", node);
set_handle_irq(sun4i_handle_irq);
return 0;
}
IRQCHIP_DECLARE(allwinner_sun4i_ic, "allwinner,sun4i-a10-ic", sun4i_of_init);
static void __exception_irq_entry sun4i_handle_irq(struct pt_regs *regs)
{
u32 hwirq;
/*
* hwirq == 0 can mean one of 3 things:
* 1) no more irqs pending
* 2) irq 0 pending
* 3) spurious irq
* So if we immediately get a reading of 0, check the irq-pending reg
* to differentiate between 2 and 3. We only do this once to avoid
* the extra check in the common case of 1 hapening after having
* read the vector-reg once.
*/
hwirq = readl(sun4i_irq_base + SUN4I_IRQ_VECTOR_REG) >> 2;
if (hwirq == 0 &&
!(readl(sun4i_irq_base + SUN4I_IRQ_PENDING_REG(0)) & BIT(0)))
return;
do {
handle_domain_irq(sun4i_irq_domain, hwirq, regs);
hwirq = readl(sun4i_irq_base + SUN4I_IRQ_VECTOR_REG) >> 2;
} while (hwirq != 0);
}
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