1 files changed, 146 insertions, 0 deletions
diff --git a/drivers/irqchip/irq-loongson-htpic.c b/drivers/irqchip/irq-loongson-htpic.c
new file mode 100644
index 000000000..f4abdf156
--- /dev/null
+++ b/drivers/irqchip/irq-loongson-htpic.c
@@ -0,0 +1,146 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *  Copyright (C) 2020, Jiaxun Yang <jiaxun.yang@flygoat.com>
+ *  Loongson HTPIC IRQ support
+ */
+
+#include <linux/init.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+#include <linux/irqchip.h>
+#include <linux/irqchip/chained_irq.h>
+#include <linux/irq.h>
+#include <linux/io.h>
+#include <linux/syscore_ops.h>
+
+#include <asm/i8259.h>
+
+#define HTPIC_MAX_PARENT_IRQ	4
+#define HTINT_NUM_VECTORS	8
+#define HTINT_EN_OFF		0x20
+
+struct loongson_htpic {
+	void __iomem *base;
+	struct irq_domain *domain;
+};
+
+static struct loongson_htpic *htpic;
+
+static void htpic_irq_dispatch(struct irq_desc *desc)
+{
+	struct loongson_htpic *priv = irq_desc_get_handler_data(desc);
+	struct irq_chip *chip = irq_desc_get_chip(desc);
+	uint32_t pending;
+
+	chained_irq_enter(chip, desc);
+	pending = readl(priv->base);
+	/* Ack all IRQs at once, otherwise IRQ flood might happen */
+	writel(pending, priv->base);
+
+	if (!pending)
+		spurious_interrupt();
+
+	while (pending) {
+		int bit = __ffs(pending);
+
+		if (unlikely(bit > 15)) {
+			spurious_interrupt();
+			break;
+		}
+
+		generic_handle_domain_irq(priv->domain, bit);
+		pending &= ~BIT(bit);
+	}
+	chained_irq_exit(chip, desc);
+}
+
+static void htpic_reg_init(void)
+{
+	int i;
+
+	for (i = 0; i < HTINT_NUM_VECTORS; i++) {
+		/* Disable all HT Vectors */
+		writel(0x0, htpic->base + HTINT_EN_OFF + i * 0x4);
+		/* Read back to force write */
+		(void) readl(htpic->base + i * 0x4);
+		/* Ack all possible pending IRQs */
+		writel(GENMASK(31, 0), htpic->base + i * 0x4);
+	}
+
+	/* Enable 16 vectors for PIC */
+	writel(0xffff, htpic->base + HTINT_EN_OFF);
+}
+
+static void htpic_resume(void)
+{
+	htpic_reg_init();
+}
+
+struct syscore_ops htpic_syscore_ops = {
+	.resume		= htpic_resume,
+};
+
+static int __init htpic_of_init(struct device_node *node, struct device_node *parent)
+{
+	unsigned int parent_irq[4];
+	int i, err;
+	int num_parents = 0;
+
+	if (htpic) {
+		pr_err("loongson-htpic: Only one HTPIC is allowed in the system\n");
+		return -ENODEV;
+	}
+
+	htpic = kzalloc(sizeof(*htpic), GFP_KERNEL);
+	if (!htpic)
+		return -ENOMEM;
+
+	htpic->base = of_iomap(node, 0);
+	if (!htpic->base) {
+		err = -ENODEV;
+		goto out_free;
+	}
+
+	htpic->domain = __init_i8259_irqs(node);
+	if (!htpic->domain) {
+		pr_err("loongson-htpic: Failed to initialize i8259 IRQs\n");
+		err = -ENOMEM;
+		goto out_iounmap;
+	}
+
+	/* Interrupt may come from any of the 4 interrupt line */
+	for (i = 0; i < HTPIC_MAX_PARENT_IRQ; i++) {
+		parent_irq[i] = irq_of_parse_and_map(node, i);
+		if (parent_irq[i] <= 0)
+			break;
+
+		num_parents++;
+	}
+
+	if (!num_parents) {
+		pr_err("loongson-htpic: Failed to get parent irqs\n");
+		err = -ENODEV;
+		goto out_remove_domain;
+	}
+
+	htpic_reg_init();
+
+	for (i = 0; i < num_parents; i++) {
+		irq_set_chained_handler_and_data(parent_irq[i],
+						htpic_irq_dispatch, htpic);
+	}
+
+	register_syscore_ops(&htpic_syscore_ops);
+
+	return 0;
+
+out_remove_domain:
+	irq_domain_remove(htpic->domain);
+out_iounmap:
+	iounmap(htpic->base);
+out_free:
+	kfree(htpic);
+	return err;
+}
+
+IRQCHIP_DECLARE(loongson_htpic, "loongson,htpic-1.0", htpic_of_init);