--- /dev/null
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2019, Jiaxun Yang <jiaxun.yang@flygoat.com>
+ * Loongson-1 platform IRQ support
+ */
+
+#include <linux/errno.h>
+#include <linux/init.h>
+#include <linux/types.h>
+#include <linux/interrupt.h>
+#include <linux/ioport.h>
+#include <linux/irqchip.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+#include <linux/io.h>
+#include <linux/irqchip/chained_irq.h>
+
+#define LS_REG_INTC_STATUS 0x00
+#define LS_REG_INTC_EN 0x04
+#define LS_REG_INTC_SET 0x08
+#define LS_REG_INTC_CLR 0x0c
+#define LS_REG_INTC_POL 0x10
+#define LS_REG_INTC_EDGE 0x14
+
+/**
+ * struct ls1x_intc_priv - private ls1x-intc data.
+ * @domain: IRQ domain.
+ * @intc_base: IO Base of intc registers.
+ */
+
+struct ls1x_intc_priv {
+ struct irq_domain *domain;
+ void __iomem *intc_base;
+};
+
+
+static void ls1x_chained_handle_irq(struct irq_desc *desc)
+{
+ struct ls1x_intc_priv *priv = irq_desc_get_handler_data(desc);
+ struct irq_chip *chip = irq_desc_get_chip(desc);
+ u32 pending;
+
+ chained_irq_enter(chip, desc);
+ pending = readl(priv->intc_base + LS_REG_INTC_STATUS) &
+ readl(priv->intc_base + LS_REG_INTC_EN);
+
+ if (!pending)
+ spurious_interrupt();
+
+ while (pending) {
+ int bit = __ffs(pending);
+
+ generic_handle_irq(irq_find_mapping(priv->domain, bit));
+ pending &= ~BIT(bit);
+ }
+
+ chained_irq_exit(chip, desc);
+}
+
+static void ls_intc_set_bit(struct irq_chip_generic *gc,
+ unsigned int offset,
+ u32 mask, bool set)
+{
+ if (set)
+ writel(readl(gc->reg_base + offset) | mask,
+ gc->reg_base + offset);
+ else
+ writel(readl(gc->reg_base + offset) & ~mask,
+ gc->reg_base + offset);
+}
+
+static int ls_intc_set_type(struct irq_data *data, unsigned int type)
+{
+ struct irq_chip_generic *gc = irq_data_get_irq_chip_data(data);
+ u32 mask = data->mask;
+
+ switch (type) {
+ case IRQ_TYPE_LEVEL_HIGH:
+ ls_intc_set_bit(gc, LS_REG_INTC_EDGE, mask, false);
+ ls_intc_set_bit(gc, LS_REG_INTC_POL, mask, true);
+ break;
+ case IRQ_TYPE_LEVEL_LOW:
+ ls_intc_set_bit(gc, LS_REG_INTC_EDGE, mask, false);
+ ls_intc_set_bit(gc, LS_REG_INTC_POL, mask, false);
+ break;
+ case IRQ_TYPE_EDGE_RISING:
+ ls_intc_set_bit(gc, LS_REG_INTC_EDGE, mask, true);
+ ls_intc_set_bit(gc, LS_REG_INTC_POL, mask, true);
+ break;
+ case IRQ_TYPE_EDGE_FALLING:
+ ls_intc_set_bit(gc, LS_REG_INTC_EDGE, mask, true);
+ ls_intc_set_bit(gc, LS_REG_INTC_POL, mask, false);
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ irqd_set_trigger_type(data, type);
+ return irq_setup_alt_chip(data, type);
+}
+
+
+static int __init ls1x_intc_of_init(struct device_node *node,
+ struct device_node *parent)
+{
+ struct irq_chip_generic *gc;
+ struct irq_chip_type *ct;
+ struct ls1x_intc_priv *priv;
+ int parent_irq, err = 0;
+
+ priv = kzalloc(sizeof(*priv), GFP_KERNEL);
+ if (!priv)
+ return -ENOMEM;
+
+ priv->intc_base = of_iomap(node, 0);
+ if (!priv->intc_base) {
+ err = -ENODEV;
+ goto out_free_priv;
+ }
+
+ parent_irq = irq_of_parse_and_map(node, 0);
+ if (!parent_irq) {
+ pr_err("ls1x-irq: unable to get parent irq\n");
+ err = -ENODEV;
+ goto out_iounmap;
+ }
+
+ /* Set up an IRQ domain */
+ priv->domain = irq_domain_add_linear(node, 32, &irq_generic_chip_ops,
+ NULL);
+ if (!priv->domain) {
+ pr_err("ls1x-irq: cannot add IRQ domain\n");
+ goto out_iounmap;
+ }
+
+ err = irq_alloc_domain_generic_chips(priv->domain, 32, 2,
+ node->full_name, handle_level_irq,
+ IRQ_NOREQUEST | IRQ_NOPROBE | IRQ_NOAUTOEN, 0,
+ IRQ_GC_INIT_MASK_CACHE);
+ if (err) {
+ pr_err("ls1x-irq: unable to register IRQ domain\n");
+ goto out_free_domain;
+ }
+
+ /* Mask all irqs */
+ writel(0x0, priv->intc_base + LS_REG_INTC_EN);
+
+ /* Ack all irqs */
+ writel(0xffffffff, priv->intc_base + LS_REG_INTC_CLR);
+
+ /* Set all irqs to high level triggered */
+ writel(0xffffffff, priv->intc_base + LS_REG_INTC_POL);
+
+ gc = irq_get_domain_generic_chip(priv->domain, 0);
+
+ gc->reg_base = priv->intc_base;
+
+ ct = gc->chip_types;
+ ct[0].type = IRQ_TYPE_LEVEL_MASK;
+ ct[0].regs.mask = LS_REG_INTC_EN;
+ ct[0].regs.ack = LS_REG_INTC_CLR;
+ ct[0].chip.irq_unmask = irq_gc_mask_set_bit;
+ ct[0].chip.irq_mask = irq_gc_mask_clr_bit;
+ ct[0].chip.irq_ack = irq_gc_ack_set_bit;
+ ct[0].chip.irq_set_type = ls_intc_set_type;
+ ct[0].handler = handle_level_irq;
+
+ ct[1].type = IRQ_TYPE_EDGE_BOTH;
+ ct[1].regs.mask = LS_REG_INTC_EN;
+ ct[1].regs.ack = LS_REG_INTC_CLR;
+ ct[1].chip.irq_unmask = irq_gc_mask_set_bit;
+ ct[1].chip.irq_mask = irq_gc_mask_clr_bit;
+ ct[1].chip.irq_ack = irq_gc_ack_set_bit;
+ ct[1].chip.irq_set_type = ls_intc_set_type;
+ ct[1].handler = handle_edge_irq;
+
+ irq_set_chained_handler_and_data(parent_irq,
+ ls1x_chained_handle_irq, priv);
+
+ return 0;
+
+out_free_domain:
+ irq_domain_remove(priv->domain);
+out_iounmap:
+ iounmap(priv->intc_base);
+out_free_priv:
+ kfree(priv);
+
+ return err;
+}
+
+IRQCHIP_DECLARE(ls1x_intc, "loongson,ls1x-intc", ls1x_intc_of_init);
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