1 files changed, 378 insertions, 0 deletions
diff --git a/drivers/irqchip/irq-loongson-pch-pic.c b/drivers/irqchip/irq-loongson-pch-pic.c
new file mode 100644
index 000000000..583939509
--- /dev/null
+++ b/drivers/irqchip/irq-loongson-pch-pic.c
@@ -0,0 +1,378 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *  Copyright (C) 2020, Jiaxun Yang <jiaxun.yang@flygoat.com>
+ *  Loongson PCH PIC support
+ */
+
+#define pr_fmt(fmt) "pch-pic: " fmt
+
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/irqchip.h>
+#include <linux/irqdomain.h>
+#include <linux/kernel.h>
+#include <linux/platform_device.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+#include <linux/of_platform.h>
+
+/* Registers */
+#define PCH_PIC_MASK		0x20
+#define PCH_PIC_HTMSI_EN	0x40
+#define PCH_PIC_EDGE		0x60
+#define PCH_PIC_CLR		0x80
+#define PCH_PIC_AUTO0		0xc0
+#define PCH_PIC_AUTO1		0xe0
+#define PCH_INT_ROUTE(irq)	(0x100 + irq)
+#define PCH_INT_HTVEC(irq)	(0x200 + irq)
+#define PCH_PIC_POL		0x3e0
+
+#define PIC_COUNT_PER_REG	32
+#define PIC_REG_COUNT		2
+#define PIC_COUNT		(PIC_COUNT_PER_REG * PIC_REG_COUNT)
+#define PIC_REG_IDX(irq_id)	((irq_id) / PIC_COUNT_PER_REG)
+#define PIC_REG_BIT(irq_id)	((irq_id) % PIC_COUNT_PER_REG)
+
+static int nr_pics;
+
+struct pch_pic {
+	void __iomem		*base;
+	struct irq_domain	*pic_domain;
+	u32			ht_vec_base;
+	raw_spinlock_t		pic_lock;
+	u32			vec_count;
+	u32			gsi_base;
+};
+
+static struct pch_pic *pch_pic_priv[MAX_IO_PICS];
+
+struct fwnode_handle *pch_pic_handle[MAX_IO_PICS];
+
+static void pch_pic_bitset(struct pch_pic *priv, int offset, int bit)
+{
+	u32 reg;
+	void __iomem *addr = priv->base + offset + PIC_REG_IDX(bit) * 4;
+
+	raw_spin_lock(&priv->pic_lock);
+	reg = readl(addr);
+	reg |= BIT(PIC_REG_BIT(bit));
+	writel(reg, addr);
+	raw_spin_unlock(&priv->pic_lock);
+}
+
+static void pch_pic_bitclr(struct pch_pic *priv, int offset, int bit)
+{
+	u32 reg;
+	void __iomem *addr = priv->base + offset + PIC_REG_IDX(bit) * 4;
+
+	raw_spin_lock(&priv->pic_lock);
+	reg = readl(addr);
+	reg &= ~BIT(PIC_REG_BIT(bit));
+	writel(reg, addr);
+	raw_spin_unlock(&priv->pic_lock);
+}
+
+static void pch_pic_mask_irq(struct irq_data *d)
+{
+	struct pch_pic *priv = irq_data_get_irq_chip_data(d);
+
+	pch_pic_bitset(priv, PCH_PIC_MASK, d->hwirq);
+	irq_chip_mask_parent(d);
+}
+
+static void pch_pic_unmask_irq(struct irq_data *d)
+{
+	struct pch_pic *priv = irq_data_get_irq_chip_data(d);
+
+	writel(BIT(PIC_REG_BIT(d->hwirq)),
+			priv->base + PCH_PIC_CLR + PIC_REG_IDX(d->hwirq) * 4);
+
+	irq_chip_unmask_parent(d);
+	pch_pic_bitclr(priv, PCH_PIC_MASK, d->hwirq);
+}
+
+static int pch_pic_set_type(struct irq_data *d, unsigned int type)
+{
+	struct pch_pic *priv = irq_data_get_irq_chip_data(d);
+	int ret = 0;
+
+	switch (type) {
+	case IRQ_TYPE_EDGE_RISING:
+		pch_pic_bitset(priv, PCH_PIC_EDGE, d->hwirq);
+		pch_pic_bitclr(priv, PCH_PIC_POL, d->hwirq);
+		irq_set_handler_locked(d, handle_edge_irq);
+		break;
+	case IRQ_TYPE_EDGE_FALLING:
+		pch_pic_bitset(priv, PCH_PIC_EDGE, d->hwirq);
+		pch_pic_bitset(priv, PCH_PIC_POL, d->hwirq);
+		irq_set_handler_locked(d, handle_edge_irq);
+		break;
+	case IRQ_TYPE_LEVEL_HIGH:
+		pch_pic_bitclr(priv, PCH_PIC_EDGE, d->hwirq);
+		pch_pic_bitclr(priv, PCH_PIC_POL, d->hwirq);
+		irq_set_handler_locked(d, handle_level_irq);
+		break;
+	case IRQ_TYPE_LEVEL_LOW:
+		pch_pic_bitclr(priv, PCH_PIC_EDGE, d->hwirq);
+		pch_pic_bitset(priv, PCH_PIC_POL, d->hwirq);
+		irq_set_handler_locked(d, handle_level_irq);
+		break;
+	default:
+		ret = -EINVAL;
+		break;
+	}
+
+	return ret;
+}
+
+static void pch_pic_ack_irq(struct irq_data *d)
+{
+	unsigned int reg;
+	struct pch_pic *priv = irq_data_get_irq_chip_data(d);
+
+	reg = readl(priv->base + PCH_PIC_EDGE + PIC_REG_IDX(d->hwirq) * 4);
+	if (reg & BIT(PIC_REG_BIT(d->hwirq))) {
+		writel(BIT(PIC_REG_BIT(d->hwirq)),
+			priv->base + PCH_PIC_CLR + PIC_REG_IDX(d->hwirq) * 4);
+	}
+	irq_chip_ack_parent(d);
+}
+
+static struct irq_chip pch_pic_irq_chip = {
+	.name			= "PCH PIC",
+	.irq_mask		= pch_pic_mask_irq,
+	.irq_unmask		= pch_pic_unmask_irq,
+	.irq_ack		= pch_pic_ack_irq,
+	.irq_set_affinity	= irq_chip_set_affinity_parent,
+	.irq_set_type		= pch_pic_set_type,
+};
+
+static int pch_pic_domain_translate(struct irq_domain *d,
+					struct irq_fwspec *fwspec,
+					unsigned long *hwirq,
+					unsigned int *type)
+{
+	struct pch_pic *priv = d->host_data;
+	struct device_node *of_node = to_of_node(fwspec->fwnode);
+
+	if (fwspec->param_count < 1)
+		return -EINVAL;
+
+	if (of_node) {
+		if (fwspec->param_count < 2)
+			return -EINVAL;
+
+		*hwirq = fwspec->param[0];
+		*type = fwspec->param[1] & IRQ_TYPE_SENSE_MASK;
+	} else {
+		*hwirq = fwspec->param[0] - priv->gsi_base;
+		*type = IRQ_TYPE_NONE;
+	}
+
+	return 0;
+}
+
+static int pch_pic_alloc(struct irq_domain *domain, unsigned int virq,
+			      unsigned int nr_irqs, void *arg)
+{
+	int err;
+	unsigned int type;
+	unsigned long hwirq;
+	struct irq_fwspec *fwspec = arg;
+	struct irq_fwspec parent_fwspec;
+	struct pch_pic *priv = domain->host_data;
+
+	err = pch_pic_domain_translate(domain, fwspec, &hwirq, &type);
+	if (err)
+		return err;
+
+	parent_fwspec.fwnode = domain->parent->fwnode;
+	parent_fwspec.param_count = 1;
+	parent_fwspec.param[0] = hwirq + priv->ht_vec_base;
+
+	err = irq_domain_alloc_irqs_parent(domain, virq, 1, &parent_fwspec);
+	if (err)
+		return err;
+
+	irq_domain_set_info(domain, virq, hwirq,
+			    &pch_pic_irq_chip, priv,
+			    handle_level_irq, NULL, NULL);
+	irq_set_probe(virq);
+
+	return 0;
+}
+
+static const struct irq_domain_ops pch_pic_domain_ops = {
+	.translate	= pch_pic_domain_translate,
+	.alloc		= pch_pic_alloc,
+	.free		= irq_domain_free_irqs_parent,
+};
+
+static void pch_pic_reset(struct pch_pic *priv)
+{
+	int i;
+
+	for (i = 0; i < PIC_COUNT; i++) {
+		/* Write vector ID */
+		writeb(priv->ht_vec_base + i, priv->base + PCH_INT_HTVEC(i));
+		/* Hardcode route to HT0 Lo */
+		writeb(1, priv->base + PCH_INT_ROUTE(i));
+	}
+
+	for (i = 0; i < PIC_REG_COUNT; i++) {
+		/* Clear IRQ cause registers, mask all interrupts */
+		writel_relaxed(0xFFFFFFFF, priv->base + PCH_PIC_MASK + 4 * i);
+		writel_relaxed(0xFFFFFFFF, priv->base + PCH_PIC_CLR + 4 * i);
+		/* Clear auto bounce, we don't need that */
+		writel_relaxed(0, priv->base + PCH_PIC_AUTO0 + 4 * i);
+		writel_relaxed(0, priv->base + PCH_PIC_AUTO1 + 4 * i);
+		/* Enable HTMSI transformer */
+		writel_relaxed(0xFFFFFFFF, priv->base + PCH_PIC_HTMSI_EN + 4 * i);
+	}
+}
+
+static int pch_pic_init(phys_addr_t addr, unsigned long size, int vec_base,
+			struct irq_domain *parent_domain, struct fwnode_handle *domain_handle,
+			u32 gsi_base)
+{
+	struct pch_pic *priv;
+
+	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	raw_spin_lock_init(&priv->pic_lock);
+	priv->base = ioremap(addr, size);
+	if (!priv->base)
+		goto free_priv;
+
+	priv->ht_vec_base = vec_base;
+	priv->vec_count = ((readq(priv->base) >> 48) & 0xff) + 1;
+	priv->gsi_base = gsi_base;
+
+	priv->pic_domain = irq_domain_create_hierarchy(parent_domain, 0,
+						priv->vec_count, domain_handle,
+						&pch_pic_domain_ops, priv);
+
+	if (!priv->pic_domain) {
+		pr_err("Failed to create IRQ domain\n");
+		goto iounmap_base;
+	}
+
+	pch_pic_reset(priv);
+	pch_pic_handle[nr_pics] = domain_handle;
+	pch_pic_priv[nr_pics++] = priv;
+
+	return 0;
+
+iounmap_base:
+	iounmap(priv->base);
+free_priv:
+	kfree(priv);
+
+	return -EINVAL;
+}
+
+#ifdef CONFIG_OF
+
+static int pch_pic_of_init(struct device_node *node,
+				struct device_node *parent)
+{
+	int err, vec_base;
+	struct resource res;
+	struct irq_domain *parent_domain;
+
+	if (of_address_to_resource(node, 0, &res))
+		return -EINVAL;
+
+	parent_domain = irq_find_host(parent);
+	if (!parent_domain) {
+		pr_err("Failed to find the parent domain\n");
+		return -ENXIO;
+	}
+
+	if (of_property_read_u32(node, "loongson,pic-base-vec", &vec_base)) {
+		pr_err("Failed to determine pic-base-vec\n");
+		return -EINVAL;
+	}
+
+	err = pch_pic_init(res.start, resource_size(&res), vec_base,
+				parent_domain, of_node_to_fwnode(node), 0);
+	if (err < 0)
+		return err;
+
+	return 0;
+}
+
+IRQCHIP_DECLARE(pch_pic, "loongson,pch-pic-1.0", pch_pic_of_init);
+
+#endif
+
+#ifdef CONFIG_ACPI
+int find_pch_pic(u32 gsi)
+{
+	int i;
+
+	/* Find the PCH_PIC that manages this GSI. */
+	for (i = 0; i < MAX_IO_PICS; i++) {
+		struct pch_pic *priv = pch_pic_priv[i];
+
+		if (!priv)
+			return -1;
+
+		if (gsi >= priv->gsi_base && gsi < (priv->gsi_base + priv->vec_count))
+			return i;
+	}
+
+	pr_err("ERROR: Unable to locate PCH_PIC for GSI %d\n", gsi);
+	return -1;
+}
+
+static int __init pch_lpc_parse_madt(union acpi_subtable_headers *header,
+					const unsigned long end)
+{
+	struct acpi_madt_lpc_pic *pchlpc_entry = (struct acpi_madt_lpc_pic *)header;
+
+	return pch_lpc_acpi_init(pch_pic_priv[0]->pic_domain, pchlpc_entry);
+}
+
+static int __init acpi_cascade_irqdomain_init(void)
+{
+	int r;
+
+	r = acpi_table_parse_madt(ACPI_MADT_TYPE_LPC_PIC, pch_lpc_parse_madt, 0);
+	if (r < 0)
+		return r;
+
+	return 0;
+}
+
+int __init pch_pic_acpi_init(struct irq_domain *parent,
+					struct acpi_madt_bio_pic *acpi_pchpic)
+{
+	int ret;
+	struct fwnode_handle *domain_handle;
+
+	if (find_pch_pic(acpi_pchpic->gsi_base) >= 0)
+		return 0;
+
+	domain_handle = irq_domain_alloc_fwnode(&acpi_pchpic->address);
+	if (!domain_handle) {
+		pr_err("Unable to allocate domain handle\n");
+		return -ENOMEM;
+	}
+
+	ret = pch_pic_init(acpi_pchpic->address, acpi_pchpic->size,
+				0, parent, domain_handle, acpi_pchpic->gsi_base);
+
+	if (ret < 0) {
+		irq_domain_free_fwnode(domain_handle);
+		return ret;
+	}
+
+	if (acpi_pchpic->id == 0)
+		ret = acpi_cascade_irqdomain_init();
+
+	return ret;
+}
+#endif