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irqchip: Add a driver for Cortina Gemini
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As a part of transitioning the Gemini platform to device tree we
create this clean, device-tree-only irqchip driver.

Cc: Janos Laube <janos.dev@gmail.com>
Cc: Paulius Zaleckas <paulius.zaleckas@gmail.com>
Cc: Hans Ulli Kroll <ulli.kroll@googlemail.com>
Cc: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
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linusw authored and Marc Zyngier committed Feb 8, 2017
1 parent f59098c commit b4d3053
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1 change: 1 addition & 0 deletions drivers/irqchip/Makefile
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Expand Up @@ -6,6 +6,7 @@ obj-$(CONFIG_ATH79) += irq-ath79-misc.o
obj-$(CONFIG_ARCH_BCM2835) += irq-bcm2835.o
obj-$(CONFIG_ARCH_BCM2835) += irq-bcm2836.o
obj-$(CONFIG_ARCH_EXYNOS) += exynos-combiner.o
obj-$(CONFIG_ARCH_GEMINI) += irq-gemini.o
obj-$(CONFIG_ARCH_HIP04) += irq-hip04.o
obj-$(CONFIG_ARCH_LPC32XX) += irq-lpc32xx.o
obj-$(CONFIG_ARCH_MMP) += irq-mmp.o
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185 changes: 185 additions & 0 deletions drivers/irqchip/irq-gemini.c
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/*
* irqchip for the Cortina Systems Gemini Copyright (C) 2017 Linus
* Walleij <linus.walleij@linaro.org>
*
* Based on arch/arm/mach-gemini/irq.c
* Copyright (C) 2001-2006 Storlink, Corp.
* Copyright (C) 2008-2009 Paulius Zaleckas <paulius.zaleckas@teltonika.lt>
*/
#include <linux/bitops.h>
#include <linux/irq.h>
#include <linux/io.h>
#include <linux/irqchip.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 <linux/of_irq.h>
#include <linux/cpu.h>

#include <asm/exception.h>
#include <asm/mach/irq.h>

#define GEMINI_NUM_IRQS 32

#define GEMINI_IRQ_SOURCE(base_addr) (base_addr + 0x00)
#define GEMINI_IRQ_MASK(base_addr) (base_addr + 0x04)
#define GEMINI_IRQ_CLEAR(base_addr) (base_addr + 0x08)
#define GEMINI_IRQ_MODE(base_addr) (base_addr + 0x0C)
#define GEMINI_IRQ_POLARITY(base_addr) (base_addr + 0x10)
#define GEMINI_IRQ_STATUS(base_addr) (base_addr + 0x14)
#define GEMINI_FIQ_SOURCE(base_addr) (base_addr + 0x20)
#define GEMINI_FIQ_MASK(base_addr) (base_addr + 0x24)
#define GEMINI_FIQ_CLEAR(base_addr) (base_addr + 0x28)
#define GEMINI_FIQ_MODE(base_addr) (base_addr + 0x2C)
#define GEMINI_FIQ_POLARITY(base_addr) (base_addr + 0x30)
#define GEMINI_FIQ_STATUS(base_addr) (base_addr + 0x34)

/**
* struct gemini_irq_data - irq data container for the Gemini IRQ controller
* @base: memory offset in virtual memory
* @chip: chip container for this instance
* @domain: IRQ domain for this instance
*/
struct gemini_irq_data {
void __iomem *base;
struct irq_chip chip;
struct irq_domain *domain;
};

static void gemini_irq_mask(struct irq_data *d)
{
struct gemini_irq_data *g = irq_data_get_irq_chip_data(d);
unsigned int mask;

mask = readl(GEMINI_IRQ_MASK(g->base));
mask &= ~BIT(irqd_to_hwirq(d));
writel(mask, GEMINI_IRQ_MASK(g->base));
}

static void gemini_irq_unmask(struct irq_data *d)
{
struct gemini_irq_data *g = irq_data_get_irq_chip_data(d);
unsigned int mask;

mask = readl(GEMINI_IRQ_MASK(g->base));
mask |= BIT(irqd_to_hwirq(d));
writel(mask, GEMINI_IRQ_MASK(g->base));
}

static void gemini_irq_ack(struct irq_data *d)
{
struct gemini_irq_data *g = irq_data_get_irq_chip_data(d);

writel(BIT(irqd_to_hwirq(d)), GEMINI_IRQ_CLEAR(g->base));
}

static int gemini_irq_set_type(struct irq_data *d, unsigned int trigger)
{
struct gemini_irq_data *g = irq_data_get_irq_chip_data(d);
int offset = irqd_to_hwirq(d);
u32 mode, polarity;

mode = readl(GEMINI_IRQ_MODE(g->base));
polarity = readl(GEMINI_IRQ_POLARITY(g->base));

if (trigger & (IRQ_TYPE_LEVEL_HIGH)) {
irq_set_handler_locked(d, handle_level_irq);
/* Disable edge detection */
mode &= ~BIT(offset);
polarity &= ~BIT(offset);
} else if (trigger & IRQ_TYPE_EDGE_RISING) {
irq_set_handler_locked(d, handle_edge_irq);
mode |= BIT(offset);
polarity |= BIT(offset);
} else if (trigger & IRQ_TYPE_EDGE_FALLING) {
irq_set_handler_locked(d, handle_edge_irq);
mode |= BIT(offset);
polarity &= ~BIT(offset);
} else {
irq_set_handler_locked(d, handle_bad_irq);
pr_warn("GEMINI IRQ: no supported trigger selected for line %d\n",
offset);
}

writel(mode, GEMINI_IRQ_MODE(g->base));
writel(polarity, GEMINI_IRQ_POLARITY(g->base));

return 0;
}

static struct irq_chip gemini_irq_chip = {
.name = "GEMINI",
.irq_ack = gemini_irq_ack,
.irq_mask = gemini_irq_mask,
.irq_unmask = gemini_irq_unmask,
.irq_set_type = gemini_irq_set_type,
};

/* Local static for the IRQ entry call */
static struct gemini_irq_data girq;

asmlinkage void __exception_irq_entry gemini_irqchip_handle_irq(struct pt_regs *regs)
{
struct gemini_irq_data *g = &girq;
int irq;
u32 status;

while ((status = readl(GEMINI_IRQ_STATUS(g->base)))) {
irq = ffs(status) - 1;
handle_domain_irq(g->domain, irq, regs);
}
}

static int gemini_irqdomain_map(struct irq_domain *d, unsigned int irq,
irq_hw_number_t hwirq)
{
struct gemini_irq_data *g = d->host_data;

irq_set_chip_data(irq, g);
/* All IRQs should set up their type, flags as bad by default */
irq_set_chip_and_handler(irq, &gemini_irq_chip, handle_bad_irq);
irq_set_probe(irq);

return 0;
}

static void gemini_irqdomain_unmap(struct irq_domain *d, unsigned int irq)
{
irq_set_chip_and_handler(irq, NULL, NULL);
irq_set_chip_data(irq, NULL);
}

static const struct irq_domain_ops gemini_irqdomain_ops = {
.map = gemini_irqdomain_map,
.unmap = gemini_irqdomain_unmap,
.xlate = irq_domain_xlate_onetwocell,
};

int __init gemini_of_init_irq(struct device_node *node,
struct device_node *parent)
{
struct gemini_irq_data *g = &girq;

/*
* Disable the idle handler by default since it is buggy
* For more info see arch/arm/mach-gemini/idle.c
*/
cpu_idle_poll_ctrl(true);

g->base = of_iomap(node, 0);
WARN(!g->base, "unable to map gemini irq registers\n");

/* Disable all interrupts */
writel(0, GEMINI_IRQ_MASK(g->base));
writel(0, GEMINI_FIQ_MASK(g->base));

g->domain = irq_domain_add_simple(node, GEMINI_NUM_IRQS, 0,
&gemini_irqdomain_ops, g);
set_handle_irq(gemini_irqchip_handle_irq);

return 0;
}
IRQCHIP_DECLARE(gemini, "cortina,gemini-interrupt-controller",
gemini_of_init_irq);

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