/*
* Support for Versatile FPGA-based IRQ controllers
*/
#include <linux/bitops.h>
#include <linux/irq.h>
#include <linux/io.h>
#include <linux/irqchip/versatile-fpga.h>
#include <linux/irqdomain.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_address.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
/**
* struct fpga_irq_data - irq data container for the FPGA IRQ controller
* @base: memory offset in virtual memory
* @chip: chip container for this instance
* @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;
struct irq_chip chip;
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_handle(unsigned int irq, struct irq_desc *desc)
{
struct fpga_irq_data *f = irq_desc_get_handler_data(desc);
u32 status = readl(f->base + IRQ_STATUS);
if (status == 0) {
do_bad_IRQ(irq, desc);
return;
}
do {
irq = ffs(status) - 1;
status &= ~(1 << irq);
generic_handle_irq(irq_find_mapping(f->domain, irq));
} while (status);
}
/*
* 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;
handle_IRQ(irq_find_mapping(f->domain, irq), regs);
handled = 1;
}
return handled;
}
/*
* Keep iterating over all registered FPGA IRQ controllers until there are
* no pending interrupts.
*/
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, &f->chip,
handle_level_irq);
set_irq_flags(irq, IRQF_VALID | IRQF_PROBE);
return 0;
}
static struct irq_domain_ops fpga_irqdomain_ops = {
.map = fpga_irqdomain_map,
.xlate = irq_domain_xlate_onetwocell,
};
void __init fpga_irq_init(void __iomem *base, const char *name, int irq_start,
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->chip.name = name;
f->chip.irq_ack = fpga_irq_mask;
f->chip.irq_mask = fpga_irq_mask;
f->chip.irq_unmask = fpga_irq_unmask;
f->valid = valid;
if (parent_irq != -1) {
irq_set_handler_data(parent_irq, f);
irq_set_chained_handler(parent_irq, fpga_irq_handle);
}
/* This will also allocate irq descriptors */
f->domain = irq_domain_add_simple(node, fls(valid), irq_start,
&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)) {
if (!irq_start)
irq_create_mapping(f->domain, i);
f->used_irqs++;
}
pr_info("FPGA IRQ chip %d \"%s\" @ %p, %u irqs\n",
fpga_irq_id, name, base, f->used_irqs);
fpga_irq_id++;
}
#ifdef CONFIG_OF
int __init fpga_irq_of_init(struct device_node *node,
struct device_node *parent)
{
void __iomem *base;
u32 clear_mask;
u32 valid_mask;
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;
fpga_irq_init(base, node->name, 0, -1, valid_mask, node);
writel(clear_mask, base + IRQ_ENABLE_CLEAR);
writel(clear_mask, base + FIQ_ENABLE_CLEAR);
return 0;
}
#endif
