1 files changed, 325 insertions, 0 deletions
diff --git a/drivers/irqchip/irq-loongson-htvec.c b/drivers/irqchip/irq-loongson-htvec.c
new file mode 100644
index 0000000000..0bff728b25
--- /dev/null
+++ b/drivers/irqchip/irq-loongson-htvec.c
@@ -0,0 +1,325 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *  Copyright (C) 2020, Jiaxun Yang <jiaxun.yang@flygoat.com>
+ *  Loongson HyperTransport Interrupt Vector support
+ */
+
+#define pr_fmt(fmt) "htvec: " fmt
+
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/irqchip.h>
+#include <linux/irqdomain.h>
+#include <linux/irqchip/chained_irq.h>
+#include <linux/kernel.h>
+#include <linux/platform_device.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+#include <linux/syscore_ops.h>
+
+/* Registers */
+#define HTVEC_EN_OFF		0x20
+#define HTVEC_MAX_PARENT_IRQ	8
+#define VEC_COUNT_PER_REG	32
+#define VEC_REG_IDX(irq_id)	((irq_id) / VEC_COUNT_PER_REG)
+#define VEC_REG_BIT(irq_id)	((irq_id) % VEC_COUNT_PER_REG)
+
+struct htvec {
+	int			num_parents;
+	void __iomem		*base;
+	struct irq_domain	*htvec_domain;
+	raw_spinlock_t		htvec_lock;
+	u32			saved_vec_en[HTVEC_MAX_PARENT_IRQ];
+};
+
+static struct htvec *htvec_priv;
+
+static void htvec_irq_dispatch(struct irq_desc *desc)
+{
+	int i;
+	u32 pending;
+	bool handled = false;
+	struct irq_chip *chip = irq_desc_get_chip(desc);
+	struct htvec *priv = irq_desc_get_handler_data(desc);
+
+	chained_irq_enter(chip, desc);
+
+	for (i = 0; i < priv->num_parents; i++) {
+		pending = readl(priv->base + 4 * i);
+		while (pending) {
+			int bit = __ffs(pending);
+
+			generic_handle_domain_irq(priv->htvec_domain,
+						  bit + VEC_COUNT_PER_REG * i);
+			pending &= ~BIT(bit);
+			handled = true;
+		}
+	}
+
+	if (!handled)
+		spurious_interrupt();
+
+	chained_irq_exit(chip, desc);
+}
+
+static void htvec_ack_irq(struct irq_data *d)
+{
+	struct htvec *priv = irq_data_get_irq_chip_data(d);
+
+	writel(BIT(VEC_REG_BIT(d->hwirq)),
+	       priv->base + VEC_REG_IDX(d->hwirq) * 4);
+}
+
+static void htvec_mask_irq(struct irq_data *d)
+{
+	u32 reg;
+	void __iomem *addr;
+	struct htvec *priv = irq_data_get_irq_chip_data(d);
+
+	raw_spin_lock(&priv->htvec_lock);
+	addr = priv->base + HTVEC_EN_OFF;
+	addr += VEC_REG_IDX(d->hwirq) * 4;
+	reg = readl(addr);
+	reg &= ~BIT(VEC_REG_BIT(d->hwirq));
+	writel(reg, addr);
+	raw_spin_unlock(&priv->htvec_lock);
+}
+
+static void htvec_unmask_irq(struct irq_data *d)
+{
+	u32 reg;
+	void __iomem *addr;
+	struct htvec *priv = irq_data_get_irq_chip_data(d);
+
+	raw_spin_lock(&priv->htvec_lock);
+	addr = priv->base + HTVEC_EN_OFF;
+	addr += VEC_REG_IDX(d->hwirq) * 4;
+	reg = readl(addr);
+	reg |= BIT(VEC_REG_BIT(d->hwirq));
+	writel(reg, addr);
+	raw_spin_unlock(&priv->htvec_lock);
+}
+
+static struct irq_chip htvec_irq_chip = {
+	.name			= "LOONGSON_HTVEC",
+	.irq_mask		= htvec_mask_irq,
+	.irq_unmask		= htvec_unmask_irq,
+	.irq_ack		= htvec_ack_irq,
+};
+
+static int htvec_domain_alloc(struct irq_domain *domain, unsigned int virq,
+			      unsigned int nr_irqs, void *arg)
+{
+	int ret;
+	unsigned long hwirq;
+	unsigned int type, i;
+	struct htvec *priv = domain->host_data;
+
+	ret = irq_domain_translate_onecell(domain, arg, &hwirq, &type);
+	if (ret)
+		return ret;
+
+	for (i = 0; i < nr_irqs; i++) {
+		irq_domain_set_info(domain, virq + i, hwirq + i, &htvec_irq_chip,
+				    priv, handle_edge_irq, NULL, NULL);
+	}
+
+	return 0;
+}
+
+static void htvec_domain_free(struct irq_domain *domain, unsigned int virq,
+				  unsigned int nr_irqs)
+{
+	int i;
+
+	for (i = 0; i < nr_irqs; i++) {
+		struct irq_data *d = irq_domain_get_irq_data(domain, virq + i);
+
+		irq_set_handler(virq + i, NULL);
+		irq_domain_reset_irq_data(d);
+	}
+}
+
+static const struct irq_domain_ops htvec_domain_ops = {
+	.translate	= irq_domain_translate_onecell,
+	.alloc		= htvec_domain_alloc,
+	.free		= htvec_domain_free,
+};
+
+static void htvec_reset(struct htvec *priv)
+{
+	u32 idx;
+
+	/* Clear IRQ cause registers, mask all interrupts */
+	for (idx = 0; idx < priv->num_parents; idx++) {
+		writel_relaxed(0x0, priv->base + HTVEC_EN_OFF + 4 * idx);
+		writel_relaxed(0xFFFFFFFF, priv->base + 4 * idx);
+	}
+}
+
+static int htvec_suspend(void)
+{
+	int i;
+
+	for (i = 0; i < htvec_priv->num_parents; i++)
+		htvec_priv->saved_vec_en[i] = readl(htvec_priv->base + HTVEC_EN_OFF + 4 * i);
+
+	return 0;
+}
+
+static void htvec_resume(void)
+{
+	int i;
+
+	for (i = 0; i < htvec_priv->num_parents; i++)
+		writel(htvec_priv->saved_vec_en[i], htvec_priv->base + HTVEC_EN_OFF + 4 * i);
+}
+
+static struct syscore_ops htvec_syscore_ops = {
+	.suspend = htvec_suspend,
+	.resume = htvec_resume,
+};
+
+static int htvec_init(phys_addr_t addr, unsigned long size,
+		int num_parents, int parent_irq[], struct fwnode_handle *domain_handle)
+{
+	int i;
+	struct htvec *priv;
+
+	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	priv->num_parents = num_parents;
+	priv->base = ioremap(addr, size);
+	raw_spin_lock_init(&priv->htvec_lock);
+
+	/* Setup IRQ domain */
+	priv->htvec_domain = irq_domain_create_linear(domain_handle,
+					(VEC_COUNT_PER_REG * priv->num_parents),
+					&htvec_domain_ops, priv);
+	if (!priv->htvec_domain) {
+		pr_err("loongson-htvec: cannot add IRQ domain\n");
+		goto iounmap_base;
+	}
+
+	htvec_reset(priv);
+
+	for (i = 0; i < priv->num_parents; i++) {
+		irq_set_chained_handler_and_data(parent_irq[i],
+						 htvec_irq_dispatch, priv);
+	}
+
+	htvec_priv = priv;
+
+	register_syscore_ops(&htvec_syscore_ops);
+
+	return 0;
+
+iounmap_base:
+	iounmap(priv->base);
+	kfree(priv);
+
+	return -EINVAL;
+}
+
+#ifdef CONFIG_OF
+
+static int htvec_of_init(struct device_node *node,
+				struct device_node *parent)
+{
+	int i, err;
+	int parent_irq[8];
+	int num_parents = 0;
+	struct resource res;
+
+	if (of_address_to_resource(node, 0, &res))
+		return -EINVAL;
+
+	/* Interrupt may come from any of the 8 interrupt lines */
+	for (i = 0; i < HTVEC_MAX_PARENT_IRQ; i++) {
+		parent_irq[i] = irq_of_parse_and_map(node, i);
+		if (parent_irq[i] <= 0)
+			break;
+
+		num_parents++;
+	}
+
+	err = htvec_init(res.start, resource_size(&res),
+			num_parents, parent_irq, of_node_to_fwnode(node));
+	if (err < 0)
+		return err;
+
+	return 0;
+}
+
+IRQCHIP_DECLARE(htvec, "loongson,htvec-1.0", htvec_of_init);
+
+#endif
+
+#ifdef CONFIG_ACPI
+static int __init pch_pic_parse_madt(union acpi_subtable_headers *header,
+					const unsigned long end)
+{
+	struct acpi_madt_bio_pic *pchpic_entry = (struct acpi_madt_bio_pic *)header;
+
+	return pch_pic_acpi_init(htvec_priv->htvec_domain, pchpic_entry);
+}
+
+static int __init pch_msi_parse_madt(union acpi_subtable_headers *header,
+					const unsigned long end)
+{
+	struct acpi_madt_msi_pic *pchmsi_entry = (struct acpi_madt_msi_pic *)header;
+
+	return pch_msi_acpi_init(htvec_priv->htvec_domain, pchmsi_entry);
+}
+
+static int __init acpi_cascade_irqdomain_init(void)
+{
+	int r;
+
+	r = acpi_table_parse_madt(ACPI_MADT_TYPE_BIO_PIC, pch_pic_parse_madt, 0);
+	if (r < 0)
+		return r;
+
+	r = acpi_table_parse_madt(ACPI_MADT_TYPE_MSI_PIC, pch_msi_parse_madt, 0);
+	if (r < 0)
+		return r;
+
+	return 0;
+}
+
+int __init htvec_acpi_init(struct irq_domain *parent,
+				   struct acpi_madt_ht_pic *acpi_htvec)
+{
+	int i, ret;
+	int num_parents, parent_irq[8];
+	struct fwnode_handle *domain_handle;
+
+	if (!acpi_htvec)
+		return -EINVAL;
+
+	num_parents = HTVEC_MAX_PARENT_IRQ;
+
+	domain_handle = irq_domain_alloc_fwnode(&acpi_htvec->address);
+	if (!domain_handle) {
+		pr_err("Unable to allocate domain handle\n");
+		return -ENOMEM;
+	}
+
+	/* Interrupt may come from any of the 8 interrupt lines */
+	for (i = 0; i < HTVEC_MAX_PARENT_IRQ; i++)
+		parent_irq[i] = irq_create_mapping(parent, acpi_htvec->cascade[i]);
+
+	ret = htvec_init(acpi_htvec->address, acpi_htvec->size,
+			num_parents, parent_irq, domain_handle);
+
+	if (ret == 0)
+		ret = acpi_cascade_irqdomain_init();
+	else
+		irq_domain_free_fwnode(domain_handle);
+
+	return ret;
+}
+
+#endif