1 files changed, 293 insertions, 0 deletions
diff --git a/drivers/irqchip/irq-loongson-pch-msi.c b/drivers/irqchip/irq-loongson-pch-msi.c
new file mode 100644
index 000000000000..a72ede90ffc6
--- /dev/null
+++ b/drivers/irqchip/irq-loongson-pch-msi.c
@@ -0,0 +1,293 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *  Copyright (C) 2020, Jiaxun Yang <jiaxun.yang@flygoat.com>
+ *  Loongson PCH MSI support
+ */
+
+#define pr_fmt(fmt) "pch-msi: " fmt
+
+#include <linux/irqchip.h>
+#include <linux/msi.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+#include <linux/of_pci.h>
+#include <linux/pci.h>
+#include <linux/slab.h>
+
+static int nr_pics;
+
+struct pch_msi_data {
+	struct mutex	msi_map_lock;
+	phys_addr_t	doorbell;
+	u32		irq_first;	/* The vector number that MSIs starts */
+	u32		num_irqs;	/* The number of vectors for MSIs */
+	unsigned long	*msi_map;
+};
+
+static struct fwnode_handle *pch_msi_handle[MAX_IO_PICS];
+
+static void pch_msi_mask_msi_irq(struct irq_data *d)
+{
+	pci_msi_mask_irq(d);
+	irq_chip_mask_parent(d);
+}
+
+static void pch_msi_unmask_msi_irq(struct irq_data *d)
+{
+	irq_chip_unmask_parent(d);
+	pci_msi_unmask_irq(d);
+}
+
+static struct irq_chip pch_msi_irq_chip = {
+	.name			= "PCH PCI MSI",
+	.irq_mask		= pch_msi_mask_msi_irq,
+	.irq_unmask		= pch_msi_unmask_msi_irq,
+	.irq_ack		= irq_chip_ack_parent,
+	.irq_set_affinity	= irq_chip_set_affinity_parent,
+};
+
+static int pch_msi_allocate_hwirq(struct pch_msi_data *priv, int num_req)
+{
+	int first;
+
+	mutex_lock(&priv->msi_map_lock);
+
+	first = bitmap_find_free_region(priv->msi_map, priv->num_irqs,
+					get_count_order(num_req));
+	if (first < 0) {
+		mutex_unlock(&priv->msi_map_lock);
+		return -ENOSPC;
+	}
+
+	mutex_unlock(&priv->msi_map_lock);
+
+	return priv->irq_first + first;
+}
+
+static void pch_msi_free_hwirq(struct pch_msi_data *priv,
+				int hwirq, int num_req)
+{
+	int first = hwirq - priv->irq_first;
+
+	mutex_lock(&priv->msi_map_lock);
+	bitmap_release_region(priv->msi_map, first, get_count_order(num_req));
+	mutex_unlock(&priv->msi_map_lock);
+}
+
+static void pch_msi_compose_msi_msg(struct irq_data *data,
+					struct msi_msg *msg)
+{
+	struct pch_msi_data *priv = irq_data_get_irq_chip_data(data);
+
+	msg->address_hi = upper_32_bits(priv->doorbell);
+	msg->address_lo = lower_32_bits(priv->doorbell);
+	msg->data = data->hwirq;
+}
+
+static struct msi_domain_info pch_msi_domain_info = {
+	.flags	= MSI_FLAG_USE_DEF_DOM_OPS | MSI_FLAG_USE_DEF_CHIP_OPS |
+		  MSI_FLAG_MULTI_PCI_MSI | MSI_FLAG_PCI_MSIX,
+	.chip	= &pch_msi_irq_chip,
+};
+
+static struct irq_chip middle_irq_chip = {
+	.name			= "PCH MSI",
+	.irq_mask		= irq_chip_mask_parent,
+	.irq_unmask		= irq_chip_unmask_parent,
+	.irq_ack		= irq_chip_ack_parent,
+	.irq_set_affinity	= irq_chip_set_affinity_parent,
+	.irq_compose_msi_msg	= pch_msi_compose_msi_msg,
+};
+
+static int pch_msi_parent_domain_alloc(struct irq_domain *domain,
+					unsigned int virq, int hwirq)
+{
+	struct irq_fwspec fwspec;
+
+	fwspec.fwnode = domain->parent->fwnode;
+	fwspec.param_count = 1;
+	fwspec.param[0] = hwirq;
+
+	return irq_domain_alloc_irqs_parent(domain, virq, 1, &fwspec);
+}
+
+static int pch_msi_middle_domain_alloc(struct irq_domain *domain,
+					   unsigned int virq,
+					   unsigned int nr_irqs, void *args)
+{
+	struct pch_msi_data *priv = domain->host_data;
+	int hwirq, err, i;
+
+	hwirq = pch_msi_allocate_hwirq(priv, nr_irqs);
+	if (hwirq < 0)
+		return hwirq;
+
+	for (i = 0; i < nr_irqs; i++) {
+		err = pch_msi_parent_domain_alloc(domain, virq + i, hwirq + i);
+		if (err)
+			goto err_hwirq;
+
+		irq_domain_set_hwirq_and_chip(domain, virq + i, hwirq + i,
+					      &middle_irq_chip, priv);
+	}
+
+	return 0;
+
+err_hwirq:
+	pch_msi_free_hwirq(priv, hwirq, nr_irqs);
+	irq_domain_free_irqs_parent(domain, virq, i - 1);
+
+	return err;
+}
+
+static void pch_msi_middle_domain_free(struct irq_domain *domain,
+					   unsigned int virq,
+					   unsigned int nr_irqs)
+{
+	struct irq_data *d = irq_domain_get_irq_data(domain, virq);
+	struct pch_msi_data *priv = irq_data_get_irq_chip_data(d);
+
+	irq_domain_free_irqs_parent(domain, virq, nr_irqs);
+	pch_msi_free_hwirq(priv, d->hwirq, nr_irqs);
+}
+
+static const struct irq_domain_ops pch_msi_middle_domain_ops = {
+	.alloc	= pch_msi_middle_domain_alloc,
+	.free	= pch_msi_middle_domain_free,
+};
+
+static int pch_msi_init_domains(struct pch_msi_data *priv,
+				struct irq_domain *parent,
+				struct fwnode_handle *domain_handle)
+{
+	struct irq_domain *middle_domain, *msi_domain;
+
+	middle_domain = irq_domain_create_linear(domain_handle,
+						priv->num_irqs,
+						&pch_msi_middle_domain_ops,
+						priv);
+	if (!middle_domain) {
+		pr_err("Failed to create the MSI middle domain\n");
+		return -ENOMEM;
+	}
+
+	middle_domain->parent = parent;
+	irq_domain_update_bus_token(middle_domain, DOMAIN_BUS_NEXUS);
+
+	msi_domain = pci_msi_create_irq_domain(domain_handle,
+					       &pch_msi_domain_info,
+					       middle_domain);
+	if (!msi_domain) {
+		pr_err("Failed to create PCI MSI domain\n");
+		irq_domain_remove(middle_domain);
+		return -ENOMEM;
+	}
+
+	return 0;
+}
+
+static int pch_msi_init(phys_addr_t msg_address, int irq_base, int irq_count,
+			struct irq_domain *parent_domain, struct fwnode_handle *domain_handle)
+{
+	int ret;
+	struct pch_msi_data *priv;
+
+	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	mutex_init(&priv->msi_map_lock);
+
+	priv->doorbell = msg_address;
+	priv->irq_first = irq_base;
+	priv->num_irqs = irq_count;
+
+	priv->msi_map = bitmap_zalloc(priv->num_irqs, GFP_KERNEL);
+	if (!priv->msi_map)
+		goto err_priv;
+
+	pr_debug("Registering %d MSIs, starting at %d\n",
+		 priv->num_irqs, priv->irq_first);
+
+	ret = pch_msi_init_domains(priv, parent_domain, domain_handle);
+	if (ret)
+		goto err_map;
+
+	pch_msi_handle[nr_pics++] = domain_handle;
+	return 0;
+
+err_map:
+	bitmap_free(priv->msi_map);
+err_priv:
+	kfree(priv);
+
+	return -EINVAL;
+}
+
+#ifdef CONFIG_OF
+static int pch_msi_of_init(struct device_node *node, struct device_node *parent)
+{
+	int err;
+	int irq_base, irq_count;
+	struct resource res;
+	struct irq_domain *parent_domain;
+
+	parent_domain = irq_find_host(parent);
+	if (!parent_domain) {
+		pr_err("Failed to find the parent domain\n");
+		return -ENXIO;
+	}
+
+	if (of_address_to_resource(node, 0, &res)) {
+		pr_err("Failed to allocate resource\n");
+		return -EINVAL;
+	}
+
+	if (of_property_read_u32(node, "loongson,msi-base-vec", &irq_base)) {
+		pr_err("Unable to parse MSI vec base\n");
+		return -EINVAL;
+	}
+
+	if (of_property_read_u32(node, "loongson,msi-num-vecs", &irq_count)) {
+		pr_err("Unable to parse MSI vec number\n");
+		return -EINVAL;
+	}
+
+	err = pch_msi_init(res.start, irq_base, irq_count, parent_domain, of_node_to_fwnode(node));
+	if (err < 0)
+		return err;
+
+	return 0;
+}
+
+IRQCHIP_DECLARE(pch_msi, "loongson,pch-msi-1.0", pch_msi_of_init);
+#endif
+
+#ifdef CONFIG_ACPI
+struct fwnode_handle *get_pch_msi_handle(int pci_segment)
+{
+	int i;
+
+	for (i = 0; i < MAX_IO_PICS; i++) {
+		if (msi_group[i].pci_segment == pci_segment)
+			return pch_msi_handle[i];
+	}
+	return NULL;
+}
+
+int __init pch_msi_acpi_init(struct irq_domain *parent,
+					struct acpi_madt_msi_pic *acpi_pchmsi)
+{
+	int ret;
+	struct fwnode_handle *domain_handle;
+
+	domain_handle = irq_domain_alloc_fwnode(&acpi_pchmsi->msg_address);
+	ret = pch_msi_init(acpi_pchmsi->msg_address, acpi_pchmsi->start,
+				acpi_pchmsi->count, parent, domain_handle);
+	if (ret < 0)
+		irq_domain_free_fwnode(domain_handle);
+
+	return ret;
+}
+#endif