1 files changed, 243 insertions, 0 deletions

diff --git a/arch/loongarch/pci/acpi.c b/arch/loongarch/pci/acpi.c
new file mode 100644
index 000000000..8235ec92b
--- /dev/null
+++ b/arch/loongarch/pci/acpi.c
@@ -0,0 +1,243 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2020-2022 Loongson Technology Corporation Limited
+ */
+#include <linux/pci.h>
+#include <linux/acpi.h>
+#include <linux/init.h>
+#include <linux/irq.h>
+#include <linux/slab.h>
+#include <linux/pci-acpi.h>
+#include <linux/pci-ecam.h>
+
+#include <asm/pci.h>
+#include <asm/numa.h>
+#include <asm/loongson.h>
+
+struct pci_root_info {
+	struct acpi_pci_root_info common;
+	struct pci_config_window *cfg;
+};
+
+void pcibios_add_bus(struct pci_bus *bus)
+{
+	acpi_pci_add_bus(bus);
+}
+
+int pcibios_root_bridge_prepare(struct pci_host_bridge *bridge)
+{
+	struct pci_config_window *cfg = bridge->bus->sysdata;
+	struct acpi_device *adev = to_acpi_device(cfg->parent);
+	struct device *bus_dev = &bridge->bus->dev;
+
+	ACPI_COMPANION_SET(&bridge->dev, adev);
+	set_dev_node(bus_dev, pa_to_nid(cfg->res.start));
+
+	return 0;
+}
+
+int acpi_pci_bus_find_domain_nr(struct pci_bus *bus)
+{
+	struct pci_config_window *cfg = bus->sysdata;
+	struct acpi_device *adev = to_acpi_device(cfg->parent);
+	struct acpi_pci_root *root = acpi_driver_data(adev);
+
+	return root->segment;
+}
+
+static void acpi_release_root_info(struct acpi_pci_root_info *ci)
+{
+	struct pci_root_info *info;
+
+	info = container_of(ci, struct pci_root_info, common);
+	pci_ecam_free(info->cfg);
+	kfree(ci->ops);
+	kfree(info);
+}
+
+static int acpi_prepare_root_resources(struct acpi_pci_root_info *ci)
+{
+	int status;
+	struct resource_entry *entry, *tmp;
+	struct acpi_device *device = ci->bridge;
+
+	status = acpi_pci_probe_root_resources(ci);
+	if (status > 0) {
+		resource_list_for_each_entry_safe(entry, tmp, &ci->resources) {
+			if (entry->res->flags & IORESOURCE_MEM) {
+				entry->offset = ci->root->mcfg_addr & GENMASK_ULL(63, 40);
+				entry->res->start |= entry->offset;
+				entry->res->end   |= entry->offset;
+			}
+		}
+		return status;
+	}
+
+	resource_list_for_each_entry_safe(entry, tmp, &ci->resources) {
+		dev_dbg(&device->dev,
+			   "host bridge window %pR (ignored)\n", entry->res);
+		resource_list_destroy_entry(entry);
+	}
+
+	return 0;
+}
+
+/*
+ * Create a PCI config space window
+ *  - reserve mem region
+ *  - alloc struct pci_config_window with space for all mappings
+ *  - ioremap the config space
+ */
+static struct pci_config_window *arch_pci_ecam_create(struct device *dev,
+		struct resource *cfgres, struct resource *busr, const struct pci_ecam_ops *ops)
+{
+	int bsz, bus_range, err;
+	struct resource *conflict;
+	struct pci_config_window *cfg;
+
+	if (busr->start > busr->end)
+		return ERR_PTR(-EINVAL);
+
+	cfg = kzalloc(sizeof(*cfg), GFP_KERNEL);
+	if (!cfg)
+		return ERR_PTR(-ENOMEM);
+
+	cfg->parent = dev;
+	cfg->ops = ops;
+	cfg->busr.start = busr->start;
+	cfg->busr.end = busr->end;
+	cfg->busr.flags = IORESOURCE_BUS;
+	bus_range = resource_size(cfgres) >> ops->bus_shift;
+
+	bsz = 1 << ops->bus_shift;
+
+	cfg->res.start = cfgres->start;
+	cfg->res.end = cfgres->end;
+	cfg->res.flags = IORESOURCE_MEM | IORESOURCE_BUSY;
+	cfg->res.name = "PCI ECAM";
+
+	conflict = request_resource_conflict(&iomem_resource, &cfg->res);
+	if (conflict) {
+		err = -EBUSY;
+		dev_err(dev, "can't claim ECAM area %pR: address conflict with %s %pR\n",
+			&cfg->res, conflict->name, conflict);
+		goto err_exit;
+	}
+
+	cfg->win = pci_remap_cfgspace(cfgres->start, bus_range * bsz);
+	if (!cfg->win)
+		goto err_exit_iomap;
+
+	if (ops->init) {
+		err = ops->init(cfg);
+		if (err)
+			goto err_exit;
+	}
+	dev_info(dev, "ECAM at %pR for %pR\n", &cfg->res, &cfg->busr);
+
+	return cfg;
+
+err_exit_iomap:
+	err = -ENOMEM;
+	dev_err(dev, "ECAM ioremap failed\n");
+err_exit:
+	pci_ecam_free(cfg);
+	return ERR_PTR(err);
+}
+
+/*
+ * Lookup the bus range for the domain in MCFG, and set up config space
+ * mapping.
+ */
+static struct pci_config_window *
+pci_acpi_setup_ecam_mapping(struct acpi_pci_root *root)
+{
+	int ret, bus_shift;
+	u16 seg = root->segment;
+	struct device *dev = &root->device->dev;
+	struct resource cfgres;
+	struct resource *bus_res = &root->secondary;
+	struct pci_config_window *cfg;
+	const struct pci_ecam_ops *ecam_ops;
+
+	ret = pci_mcfg_lookup(root, &cfgres, &ecam_ops);
+	if (ret < 0) {
+		dev_err(dev, "%04x:%pR ECAM region not found, use default value\n", seg, bus_res);
+		ecam_ops = &loongson_pci_ecam_ops;
+		root->mcfg_addr = mcfg_addr_init(0);
+	}
+
+	bus_shift = ecam_ops->bus_shift ? : 20;
+
+	if (bus_shift == 20)
+		cfg = pci_ecam_create(dev, &cfgres, bus_res, ecam_ops);
+	else {
+		cfgres.start = root->mcfg_addr + (bus_res->start << bus_shift);
+		cfgres.end = cfgres.start + (resource_size(bus_res) << bus_shift) - 1;
+		cfgres.end |= BIT(28) + (((PCI_CFG_SPACE_EXP_SIZE - 1) & 0xf00) << 16);
+		cfgres.flags = IORESOURCE_MEM;
+		cfg = arch_pci_ecam_create(dev, &cfgres, bus_res, ecam_ops);
+	}
+
+	if (IS_ERR(cfg)) {
+		dev_err(dev, "%04x:%pR error %ld mapping ECAM\n", seg, bus_res, PTR_ERR(cfg));
+		return NULL;
+	}
+
+	return cfg;
+}
+
+struct pci_bus *pci_acpi_scan_root(struct acpi_pci_root *root)
+{
+	struct pci_bus *bus;
+	struct pci_root_info *info;
+	struct acpi_pci_root_ops *root_ops;
+	int domain = root->segment;
+	int busnum = root->secondary.start;
+
+	info = kzalloc(sizeof(*info), GFP_KERNEL);
+	if (!info) {
+		pr_warn("pci_bus %04x:%02x: ignored (out of memory)\n", domain, busnum);
+		return NULL;
+	}
+
+	root_ops = kzalloc(sizeof(*root_ops), GFP_KERNEL);
+	if (!root_ops) {
+		kfree(info);
+		return NULL;
+	}
+
+	info->cfg = pci_acpi_setup_ecam_mapping(root);
+	if (!info->cfg) {
+		kfree(info);
+		kfree(root_ops);
+		return NULL;
+	}
+
+	root_ops->release_info = acpi_release_root_info;
+	root_ops->prepare_resources = acpi_prepare_root_resources;
+	root_ops->pci_ops = (struct pci_ops *)&info->cfg->ops->pci_ops;
+
+	bus = pci_find_bus(domain, busnum);
+	if (bus) {
+		memcpy(bus->sysdata, info->cfg, sizeof(struct pci_config_window));
+		kfree(info);
+	} else {
+		struct pci_bus *child;
+
+		bus = acpi_pci_root_create(root, root_ops,
+					   &info->common, info->cfg);
+		if (!bus) {
+			kfree(info);
+			kfree(root_ops);
+			return NULL;
+		}
+
+		pci_bus_size_bridges(bus);
+		pci_bus_assign_resources(bus);
+		list_for_each_entry(child, &bus->children, node)
+			pcie_bus_configure_settings(child);
+	}
+
+	return bus;
+}