/*
* J-Core SoC AIC driver
*
* Copyright (C) 2015-2016 Smart Energy Instruments, Inc.
*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*/
#include <linux/irq.h>
#include <linux/io.h>
#include <linux/irqchip.h>
#include <linux/irqdomain.h>
#include <linux/cpu.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/of_irq.h>
#define JCORE_AIC_MAX_HWIRQ 127
#define JCORE_AIC1_MIN_HWIRQ 16
#define JCORE_AIC2_MIN_HWIRQ 64
#define JCORE_AIC1_INTPRI_REG 8
static struct irq_chip jcore_aic;
/*
* The J-Core AIC1 and AIC2 are cpu-local interrupt controllers and do
* not distinguish or use distinct irq number ranges for per-cpu event
* interrupts (timer, IPI). Since information to determine whether a
* particular irq number should be treated as per-cpu is not available
* at mapping time, we use a wrapper handler function which chooses
* the right handler at runtime based on whether IRQF_PERCPU was used
* when requesting the irq.
*/
static void handle_jcore_irq(struct irq_desc *desc)
{
if (irqd_is_per_cpu(irq_desc_get_irq_data(desc)))
handle_percpu_irq(desc);
else
handle_simple_irq(desc);
}
static int jcore_aic_irqdomain_map(struct irq_domain *d, unsigned int irq,
irq_hw_number_t hwirq)
{
struct irq_chip *aic = d->host_data;
irq_set_chip_and_handler(irq, aic, handle_jcore_irq);
return 0;
}
static const struct irq_domain_ops jcore_aic_irqdomain_ops = {
.map = jcore_aic_irqdomain_map,
.xlate = irq_domain_xlate_onecell,
};
static void noop(struct irq_data *data)
{
}
static int __init aic_irq_of_init(struct device_node *node,
struct device_node *parent)
{
unsigned min_irq = JCORE_AIC2_MIN_HWIRQ;
unsigned dom_sz = JCORE_AIC_MAX_HWIRQ+1;
struct irq_domain *domain;
pr_info("Initializing J-Core AIC\n");
/* AIC1 needs priority initialization to receive interrupts. */
if (of_device_is_compatible(node, "jcore,aic1")) {
unsigned cpu;
for_each_present_cpu(cpu) {
void __iomem *base = of_iomap(node, cpu);
if (!base) {
pr_err("Unable to map AIC for cpu %u\n", cpu);
return -ENOMEM;
}
__raw_writel(0xffffffff, base + JCORE_AIC1_INTPRI_REG);
iounmap(base);
}
min_irq = JCORE_AIC1_MIN_HWIRQ;
}
/*
* The irq chip framework requires either mask/unmask or enable/disable
* function pointers to be provided, but the hardware does not have any
* such mechanism; the only interrupt masking is at the cpu level and
* it affects all interrupts. We provide dummy mask/unmask. The hardware
* handles all interrupt control and clears pending status when the cpu
* accepts the interrupt.
*/
jcore_aic.irq_mask = noop;
jcore_aic.irq_unmask = noop;
jcore_aic.name = "AIC";
domain = irq_domain_add_linear(node, dom_sz, &jcore_aic_irqdomain_ops,
&jcore_aic);
if (!domain)
return -ENOMEM;
irq_create_strict_mappings(domain, min_irq, min_irq, dom_sz - min_irq);
return 0;
}
IRQCHIP_DECLARE(jcore_aic2, "jcore,aic2", aic_irq_of_init);
IRQCHIP_DECLARE(jcore_aic1, "jcore,aic1", aic_irq_of_init);
