// SPDX-License-Identifier: GPL-2.0
/*
* Support for Versatile FPGA-based IRQ controllers
*/
#include <linux/bitops.h>
#include <linux/irq.h>
#include <linux/io.h>
#include <linux/irqchip.h>
#include <linux/irqchip/chained_irq.h>
#include <linux/irqdomain.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/of_irq.h>
#include <linux/seq_file.h>
#include <asm/exception.h>
#include <asm/mach/irq.h>
#define IRQ_STATUS 0x00
#define IRQ_RAW_STATUS 0x04
#define IRQ_ENABLE_SET 0x08
#define IRQ_ENABLE_CLEAR 0x0c
#define INT_SOFT_SET 0x10
#define INT_SOFT_CLEAR 0x14
#define FIQ_STATUS 0x20
#define FIQ_RAW_STATUS 0x24
#define FIQ_ENABLE 0x28
#define FIQ_ENABLE_SET 0x28
#define FIQ_ENABLE_CLEAR 0x2C
#define PIC_ENABLES 0x20 /* set interrupt pass through bits */
/**
* struct fpga_irq_data - irq data container for the FPGA IRQ controller
* @base: memory offset in virtual memory
* @domain: IRQ domain for this instance
* @valid: mask for valid IRQs on this controller
* @used_irqs: number of active IRQs on this controller
*/
struct fpga_irq_data {
void __iomem *base;
u32 valid;
struct irq_domain *domain;
u8 used_irqs;
};
/* we cannot allocate memory when the controllers are initially registered */
static struct fpga_irq_data fpga_irq_devices[CONFIG_VERSATILE_FPGA_IRQ_NR];
static int fpga_irq_id;
static void fpga_irq_mask(struct irq_data *d)
{
struct fpga_irq_data *f = irq_data_get_irq_chip_data(d);
u32 mask = 1 << d->hwirq;
writel(mask, f->base + IRQ_ENABLE_CLEAR);
}
static void fpga_irq_unmask(struct irq_data *d)
{
struct fpga_irq_data *f = irq_data_get_irq_chip_data(d);
u32 mask = 1 << d->hwirq;
writel(mask, f->base + IRQ_ENABLE_SET);
}
static void fpga_irq_print_chip(struct irq_data *d, struct seq_file *p)
{
struct fpga_irq_data *f = irq_data_get_irq_chip_data(d);
seq_printf(p, irq_domain_get_of_node(f->domain)->name);
}
static const struct irq_chip fpga_chip = {
.irq_ack = fpga_irq_mask,
.irq_mask = fpga_irq_mask,
.irq_unmask = fpga_irq_unmask,
.irq_print_chip = fpga_irq_print_chip,
};
static void fpga_irq_handle(struct irq_desc *desc)
{
struct irq_chip *chip = irq_desc_get_chip(desc);
struct fpga_irq_data *f = irq_desc_get_handler_data(desc);
u32 status;
chained_irq_enter(chip, desc);
status = readl(f->base + IRQ_STATUS);
if (status == 0) {
do_bad_IRQ(desc);
goto out;
}
do {
unsigned int irq = ffs(status) - 1;
status &= ~(1 << irq);
generic_handle_domain_irq(f->domain, irq);
} while (status);
out:
chained_irq_exit(chip, desc);
}
/*
* Handle each interrupt in a single FPGA IRQ controller. Returns non-zero
* if we've handled at least one interrupt. This does a single read of the
* status register and handles all interrupts in order from LSB first.
*/
static int handle_one_fpga(struct fpga_irq_data *f, struct pt_regs *regs)
{
int handled = 0;
int irq;
u32 status;
while ((status = readl(f->base + IRQ_STATUS))) {
irq = ffs(status) - 1;
generic_handle_domain_irq(f->domain, irq);
handled = 1;
}
return handled;
}
/*
* Keep iterating over all registered FPGA IRQ controllers until there are
* no pending interrupts.
*/
static asmlinkage void __exception_irq_entry fpga_handle_irq(struct pt_regs *regs)
{
int i, handled;
do {
for (i = 0, handled = 0; i < fpga_irq_id; ++i)
handled |= handle_one_fpga(&fpga_irq_devices[i], regs);
} while (handled);
}
static int fpga_irqdomain_map(struct irq_domain *d, unsigned int irq,
irq_hw_number_t hwirq)
{
struct fpga_irq_data *f = d->host_data;
/* Skip invalid IRQs, only register handlers for the real ones */
if (!(f->valid & BIT(hwirq)))
return -EPERM;
irq_set_chip_data(irq, f);
irq_set_chip_and_handler(irq, &fpga_chip, handle_level_irq);
irq_set_probe(irq);
return 0;
}
static const struct irq_domain_ops fpga_irqdomain_ops = {
.map = fpga_irqdomain_map,
.xlate = irq_domain_xlate_onetwocell,
};
static void __init fpga_irq_init(void __iomem *base, int parent_irq,
u32 valid, struct device_node *node)
{
struct fpga_irq_data *f;
int i;
if (fpga_irq_id >= ARRAY_SIZE(fpga_irq_devices)) {
pr_err("%s: too few FPGA IRQ controllers, increase CONFIG_VERSATILE_FPGA_IRQ_NR\n", __func__);
return;
}
f = &fpga_irq_devices[fpga_irq_id];
f->base = base;
f->valid = valid;
if (parent_irq != -1) {
irq_set_chained_handler_and_data(parent_irq, fpga_irq_handle,
f);
}
f->domain = irq_domain_add_linear(node, fls(valid),
&fpga_irqdomain_ops, f);
/* This will allocate all valid descriptors in the linear case */
for (i = 0; i < fls(valid); i++)
if (valid & BIT(i)) {
/* Is this still required? */
irq_create_mapping(f->domain, i);
f->used_irqs++;
}
pr_info("FPGA IRQ chip %d \"%s\" @ %p, %u irqs",
fpga_irq_id, node->name, base, f->used_irqs);
if (parent_irq != -1)
pr_cont(", parent IRQ: %d\n", parent_irq);
else
pr_cont("\n");
fpga_irq_id++;
}
#ifdef CONFIG_OF
static int __init fpga_irq_of_init(struct device_node *node,
struct device_node *parent)
{
void __iomem *base;
u32 clear_mask;
u32 valid_mask;
int parent_irq;
if (WARN_ON(!node))
return -ENODEV;
base = of_iomap(node, 0);
WARN(!base, "unable to map fpga irq registers\n");
if (of_property_read_u32(node, "clear-mask", &clear_mask))
clear_mask = 0;
if (of_property_read_u32(node, "valid-mask", &valid_mask))
valid_mask = 0;
writel(clear_mask, base + IRQ_ENABLE_CLEAR);
writel(clear_mask, base + FIQ_ENABLE_CLEAR);
/* Some chips are cascaded from a parent IRQ */
parent_irq = irq_of_parse_and_map(node, 0);
if (!parent_irq) {
set_handle_irq(fpga_handle_irq);
parent_irq = -1;
}
fpga_irq_init(base, parent_irq, valid_mask, node);
/*
* On Versatile AB/PB, some secondary interrupts have a direct
* pass-thru to the primary controller for IRQs 20 and 22-31 which need
* to be enabled. See section 3.10 of the Versatile AB user guide.
*/
if (of_device_is_compatible(node, "arm,versatile-sic"))
writel(0xffd00000, base + PIC_ENABLES);
return 0;
}
IRQCHIP_DECLARE(arm_fpga, "arm,versatile-fpga-irq", fpga_irq_of_init);
IRQCHIP_DECLARE(arm_fpga_sic, "arm,versatile-sic", fpga_irq_of_init);
#endif
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