irqchip/gemini: Refactor Gemini driver to reflect Faraday origin

The Gemini irqchip turns out to be a standard IP component from
Faraday Technology named FTINTC010 after some research and new
information.

- Rename the driver and all symbols to reflect the new information.
- Add the new compatible string "faraday,ftintc010"
- Create a Kconfig symbol CONFIG_FARADAY_FTINTC010 so that SoCs
  using this interrupt controller can easily select and reuse it
  instead of hardwiring it to ARCH_GEMINI

I have created a separate patch to select the new Kconfig symbol
from the Gemini machine, which will be merged through the ARM
SoC tree.

Cc: Greentime Hu <green.hu@gmail.com>
Cc: Paulius Zaleckas <paulius.zaleckas@gmail.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

1 files changed, 187 insertions, 0 deletions

diff --git a/drivers/irqchip/irq-ftintc010.c b/drivers/irqchip/irq-ftintc010.c
new file mode 100644
index 000000000000..81929aa33990
--- /dev/null
+++ b/drivers/irqchip/irq-ftintc010.c
@@ -0,0 +1,187 @@
+/*
+ * irqchip for the Faraday Technology FTINTC010 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@gmail.com>
+ */
+#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 FT010_NUM_IRQS 32
+
+#define FT010_IRQ_SOURCE(base_addr)	(base_addr + 0x00)
+#define FT010_IRQ_MASK(base_addr)	(base_addr + 0x04)
+#define FT010_IRQ_CLEAR(base_addr)	(base_addr + 0x08)
+#define FT010_IRQ_MODE(base_addr)	(base_addr + 0x0C)
+#define FT010_IRQ_POLARITY(base_addr)	(base_addr + 0x10)
+#define FT010_IRQ_STATUS(base_addr)	(base_addr + 0x14)
+#define FT010_FIQ_SOURCE(base_addr)	(base_addr + 0x20)
+#define FT010_FIQ_MASK(base_addr)	(base_addr + 0x24)
+#define FT010_FIQ_CLEAR(base_addr)	(base_addr + 0x28)
+#define FT010_FIQ_MODE(base_addr)	(base_addr + 0x2C)
+#define FT010_FIQ_POLARITY(base_addr)	(base_addr + 0x30)
+#define FT010_FIQ_STATUS(base_addr)	(base_addr + 0x34)
+
+/**
+ * struct ft010_irq_data - irq data container for the Faraday IRQ controller
+ * @base: memory offset in virtual memory
+ * @chip: chip container for this instance
+ * @domain: IRQ domain for this instance
+ */
+struct ft010_irq_data {
+	void __iomem *base;
+	struct irq_chip chip;
+	struct irq_domain *domain;
+};
+
+static void ft010_irq_mask(struct irq_data *d)
+{
+	struct ft010_irq_data *f = irq_data_get_irq_chip_data(d);
+	unsigned int mask;
+
+	mask = readl(FT010_IRQ_MASK(f->base));
+	mask &= ~BIT(irqd_to_hwirq(d));
+	writel(mask, FT010_IRQ_MASK(f->base));
+}
+
+static void ft010_irq_unmask(struct irq_data *d)
+{
+	struct ft010_irq_data *f = irq_data_get_irq_chip_data(d);
+	unsigned int mask;
+
+	mask = readl(FT010_IRQ_MASK(f->base));
+	mask |= BIT(irqd_to_hwirq(d));
+	writel(mask, FT010_IRQ_MASK(f->base));
+}
+
+static void ft010_irq_ack(struct irq_data *d)
+{
+	struct ft010_irq_data *f = irq_data_get_irq_chip_data(d);
+
+	writel(BIT(irqd_to_hwirq(d)), FT010_IRQ_CLEAR(f->base));
+}
+
+static int ft010_irq_set_type(struct irq_data *d, unsigned int trigger)
+{
+	struct ft010_irq_data *f = irq_data_get_irq_chip_data(d);
+	int offset = irqd_to_hwirq(d);
+	u32 mode, polarity;
+
+	mode = readl(FT010_IRQ_MODE(f->base));
+	polarity = readl(FT010_IRQ_POLARITY(f->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, FT010_IRQ_MODE(f->base));
+	writel(polarity, FT010_IRQ_POLARITY(f->base));
+
+	return 0;
+}
+
+static struct irq_chip ft010_irq_chip = {
+	.name		= "FTINTC010",
+	.irq_ack	= ft010_irq_ack,
+	.irq_mask	= ft010_irq_mask,
+	.irq_unmask	= ft010_irq_unmask,
+	.irq_set_type	= ft010_irq_set_type,
+};
+
+/* Local static for the IRQ entry call */
+static struct ft010_irq_data firq;
+
+asmlinkage void __exception_irq_entry ft010_irqchip_handle_irq(struct pt_regs *regs)
+{
+	struct ft010_irq_data *f = &firq;
+	int irq;
+	u32 status;
+
+	while ((status = readl(FT010_IRQ_STATUS(f->base)))) {
+		irq = ffs(status) - 1;
+		handle_domain_irq(f->domain, irq, regs);
+	}
+}
+
+static int ft010_irqdomain_map(struct irq_domain *d, unsigned int irq,
+				irq_hw_number_t hwirq)
+{
+	struct ft010_irq_data *f = d->host_data;
+
+	irq_set_chip_data(irq, f);
+	/* All IRQs should set up their type, flags as bad by default */
+	irq_set_chip_and_handler(irq, &ft010_irq_chip, handle_bad_irq);
+	irq_set_probe(irq);
+
+	return 0;
+}
+
+static void ft010_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 ft010_irqdomain_ops = {
+	.map = ft010_irqdomain_map,
+	.unmap = ft010_irqdomain_unmap,
+	.xlate = irq_domain_xlate_onetwocell,
+};
+
+int __init ft010_of_init_irq(struct device_node *node,
+			      struct device_node *parent)
+{
+	struct ft010_irq_data *f = &firq;
+
+	/*
+	 * 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);
+
+	f->base = of_iomap(node, 0);
+	WARN(!f->base, "unable to map gemini irq registers\n");
+
+	/* Disable all interrupts */
+	writel(0, FT010_IRQ_MASK(f->base));
+	writel(0, FT010_FIQ_MASK(f->base));
+
+	f->domain = irq_domain_add_simple(node, FT010_NUM_IRQS, 0,
+					  &ft010_irqdomain_ops, f);
+	set_handle_irq(ft010_irqchip_handle_irq);
+
+	return 0;
+}
+IRQCHIP_DECLARE(faraday, "faraday,ftintc010",
+		ft010_of_init_irq);
+IRQCHIP_DECLARE(gemini, "cortina,gemini-interrupt-controller",
+		ft010_of_init_irq);