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// SPDX-License-Identifier: GPL-2.0-only
// Copyright 2021 Jonathan Neuschäfer
#include <linux/irqchip.h>
#include <linux/of_address.h>
#include <linux/of_irq.h>
#include <linux/printk.h>
#include <asm/exception.h>
#define AIC_SCR(x) ((x)*4) /* Source control registers */
#define AIC_GEN 0x84 /* Interrupt group enable control register */
#define AIC_GRSR 0x88 /* Interrupt group raw status register */
#define AIC_IRSR 0x100 /* Interrupt raw status register */
#define AIC_IASR 0x104 /* Interrupt active status register */
#define AIC_ISR 0x108 /* Interrupt status register */
#define AIC_IPER 0x10c /* Interrupt priority encoding register */
#define AIC_ISNR 0x110 /* Interrupt source number register */
#define AIC_IMR 0x114 /* Interrupt mask register */
#define AIC_OISR 0x118 /* Output interrupt status register */
#define AIC_MECR 0x120 /* Mask enable command register */
#define AIC_MDCR 0x124 /* Mask disable command register */
#define AIC_SSCR 0x128 /* Source set command register */
#define AIC_SCCR 0x12c /* Source clear command register */
#define AIC_EOSCR 0x130 /* End of service command register */
#define AIC_SCR_SRCTYPE_LOW_LEVEL (0 << 6)
#define AIC_SCR_SRCTYPE_HIGH_LEVEL (1 << 6)
#define AIC_SCR_SRCTYPE_NEG_EDGE (2 << 6)
#define AIC_SCR_SRCTYPE_POS_EDGE (3 << 6)
#define AIC_SCR_PRIORITY(x) (x)
#define AIC_SCR_PRIORITY_MASK 0x7
#define AIC_NUM_IRQS 32
struct wpcm450_aic {
void __iomem *regs;
struct irq_domain *domain;
};
static struct wpcm450_aic *aic;
static void wpcm450_aic_init_hw(void)
{
int i;
/* Disable (mask) all interrupts */
writel(0xffffffff, aic->regs + AIC_MDCR);
/*
* Make sure the interrupt controller is ready to serve new interrupts.
* Reading from IPER indicates that the nIRQ signal may be deasserted,
* and writing to EOSCR indicates that interrupt handling has finished.
*/
readl(aic->regs + AIC_IPER);
writel(0, aic->regs + AIC_EOSCR);
/* Initialize trigger mode and priority of each interrupt source */
for (i = 0; i < AIC_NUM_IRQS; i++)
writel(AIC_SCR_SRCTYPE_HIGH_LEVEL | AIC_SCR_PRIORITY(7),
aic->regs + AIC_SCR(i));
}
static void __exception_irq_entry wpcm450_aic_handle_irq(struct pt_regs *regs)
{
int hwirq;
/* Determine the interrupt source */
/* Read IPER to signal that nIRQ can be de-asserted */
hwirq = readl(aic->regs + AIC_IPER) / 4;
generic_handle_domain_irq(aic->domain, hwirq);
}
static void wpcm450_aic_eoi(struct irq_data *d)
{
/* Signal end-of-service */
writel(0, aic->regs + AIC_EOSCR);
}
static void wpcm450_aic_mask(struct irq_data *d)
{
unsigned int mask = BIT(d->hwirq);
/* Disable (mask) the interrupt */
writel(mask, aic->regs + AIC_MDCR);
}
static void wpcm450_aic_unmask(struct irq_data *d)
{
unsigned int mask = BIT(d->hwirq);
/* Enable (unmask) the interrupt */
writel(mask, aic->regs + AIC_MECR);
}
static int wpcm450_aic_set_type(struct irq_data *d, unsigned int flow_type)
{
/*
* The hardware supports high/low level, as well as rising/falling edge
* modes, and the DT binding accommodates for that, but as long as
* other modes than high level mode are not used and can't be tested,
* they are rejected in this driver.
*/
if ((flow_type & IRQ_TYPE_SENSE_MASK) != IRQ_TYPE_LEVEL_HIGH)
return -EINVAL;
return 0;
}
static struct irq_chip wpcm450_aic_chip = {
.name = "wpcm450-aic",
.irq_eoi = wpcm450_aic_eoi,
.irq_mask = wpcm450_aic_mask,
.irq_unmask = wpcm450_aic_unmask,
.irq_set_type = wpcm450_aic_set_type,
};
static int wpcm450_aic_map(struct irq_domain *d, unsigned int irq, irq_hw_number_t hwirq)
{
if (hwirq >= AIC_NUM_IRQS)
return -EPERM;
irq_set_chip_and_handler(irq, &wpcm450_aic_chip, handle_fasteoi_irq);
irq_set_chip_data(irq, aic);
irq_set_probe(irq);
return 0;
}
static const struct irq_domain_ops wpcm450_aic_ops = {
.map = wpcm450_aic_map,
.xlate = irq_domain_xlate_twocell,
};
static int __init wpcm450_aic_of_init(struct device_node *node,
struct device_node *parent)
{
if (parent)
return -EINVAL;
aic = kzalloc(sizeof(*aic), GFP_KERNEL);
if (!aic)
return -ENOMEM;
aic->regs = of_iomap(node, 0);
if (!aic->regs) {
pr_err("Failed to map WPCM450 AIC registers\n");
return -ENOMEM;
}
wpcm450_aic_init_hw();
set_handle_irq(wpcm450_aic_handle_irq);
aic->domain = irq_domain_add_linear(node, AIC_NUM_IRQS, &wpcm450_aic_ops, aic);
return 0;
}
IRQCHIP_DECLARE(wpcm450_aic, "nuvoton,wpcm450-aic", wpcm450_aic_of_init);
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