PCI/ACPI: Add interface acpi_pci_root_create()

Introduce common interface acpi_pci_root_create() and related data
structures to create PCI root bus for ACPI PCI host bridges. It will
be used to kill duplicated arch specific code for IA64 and x86. It may
also help ARM64 in future.

Reviewed-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Tested-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Jiang Liu <jiang.liu@linux.intel.com>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

2 files changed, 228 insertions, 0 deletions

diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c
index 393706a5261b..850d7bf0c873 100644
--- a/drivers/acpi/pci_root.c
+++ b/drivers/acpi/pci_root.c
@@ -652,6 +652,210 @@ static void acpi_pci_root_remove(struct acpi_device *device)
         kfree(root);
 }
 
+/*
+ * Following code to support acpi_pci_root_create() is copied from
+ * arch/x86/pci/acpi.c and modified so it could be reused by x86, IA64
+ * and ARM64.
+ */
+static void acpi_pci_root_validate_resources(struct device *dev,
+                                             struct list_head *resources,
+                                             unsigned long type)
+{
+        LIST_HEAD(list);
+        struct resource *res1, *res2, *root = NULL;
+        struct resource_entry *tmp, *entry, *entry2;
+
+        BUG_ON((type & (IORESOURCE_MEM | IORESOURCE_IO)) == 0);
+        root = (type & IORESOURCE_MEM) ? &iomem_resource : &ioport_resource;
+
+        list_splice_init(resources, &list);
+        resource_list_for_each_entry_safe(entry, tmp, &list) {
+                bool free = false;
+                resource_size_t end;
+
+                res1 = entry->res;
+                if (!(res1->flags & type))
+                        goto next;
+
+                /* Exclude non-addressable range or non-addressable portion */
+                end = min(res1->end, root->end);
+                if (end <= res1->start) {
+                        dev_info(dev, "host bridge window %pR (ignored, not CPU addressable)\n",
+                                 res1);
+                        free = true;
+                        goto next;
+                } else if (res1->end != end) {
+                        dev_info(dev, "host bridge window %pR ([%#llx-%#llx] ignored, not CPU addressable)\n",
+                                 res1, (unsigned long long)end + 1,
+                                 (unsigned long long)res1->end);
+                        res1->end = end;
+                }
+
+                resource_list_for_each_entry(entry2, resources) {
+                        res2 = entry2->res;
+                        if (!(res2->flags & type))
+                                continue;
+
+                        /*
+                         * I don't like throwing away windows because then
+                         * our resources no longer match the ACPI _CRS, but
+                         * the kernel resource tree doesn't allow overlaps.
+                         */
+                        if (resource_overlaps(res1, res2)) {
+                                res2->start = min(res1->start, res2->start);
+                                res2->end = max(res1->end, res2->end);
+                                dev_info(dev, "host bridge window expanded to %pR; %pR ignored\n",
+                                         res2, res1);
+                                free = true;
+                                goto next;
+                        }
+                }
+
+next:
+                resource_list_del(entry);
+                if (free)
+                        resource_list_free_entry(entry);
+                else
+                        resource_list_add_tail(entry, resources);
+        }
+}
+
+int acpi_pci_probe_root_resources(struct acpi_pci_root_info *info)
+{
+        int ret;
+        struct list_head *list = &info->resources;
+        struct acpi_device *device = info->bridge;
+        struct resource_entry *entry, *tmp;
+        unsigned long flags;
+
+        flags = IORESOURCE_IO | IORESOURCE_MEM | IORESOURCE_MEM_8AND16BIT;
+        ret = acpi_dev_get_resources(device, list,
+                                     acpi_dev_filter_resource_type_cb,
+                                     (void *)flags);
+        if (ret < 0)
+                dev_warn(&device->dev,
+                         "failed to parse _CRS method, error code %d\n", ret);
+        else if (ret == 0)
+                dev_dbg(&device->dev,
+                        "no IO and memory resources present in _CRS\n");
+        else {
+                resource_list_for_each_entry_safe(entry, tmp, list) {
+                        if (entry->res->flags & IORESOURCE_DISABLED)
+                                resource_list_destroy_entry(entry);
+                        else
+                                entry->res->name = info->name;
+                }
+                acpi_pci_root_validate_resources(&device->dev, list,
+                                                 IORESOURCE_MEM);
+                acpi_pci_root_validate_resources(&device->dev, list,
+                                                 IORESOURCE_IO);
+        }
+
+        return ret;
+}
+
+static void pci_acpi_root_add_resources(struct acpi_pci_root_info *info)
+{
+        struct resource_entry *entry, *tmp;
+        struct resource *res, *conflict, *root = NULL;
+
+        resource_list_for_each_entry_safe(entry, tmp, &info->resources) {
+                res = entry->res;
+                if (res->flags & IORESOURCE_MEM)
+                        root = &iomem_resource;
+                else if (res->flags & IORESOURCE_IO)
+                        root = &ioport_resource;
+                else
+                        continue;
+
+                conflict = insert_resource_conflict(root, res);
+                if (conflict) {
+                        dev_info(&info->bridge->dev,
+                                 "ignoring host bridge window %pR (conflicts with %s %pR)\n",
+                                 res, conflict->name, conflict);
+                        resource_list_destroy_entry(entry);
+                }
+        }
+}
+
+static void __acpi_pci_root_release_info(struct acpi_pci_root_info *info)
+{
+        struct resource *res;
+        struct resource_entry *entry, *tmp;
+
+        if (!info)
+                return;
+
+        resource_list_for_each_entry_safe(entry, tmp, &info->resources) {
+                res = entry->res;
+                if (res->parent &&
+                    (res->flags & (IORESOURCE_MEM | IORESOURCE_IO)))
+                        release_resource(res);
+                resource_list_destroy_entry(entry);
+        }
+
+        info->ops->release_info(info);
+}
+
+static void acpi_pci_root_release_info(struct pci_host_bridge *bridge)
+{
+        struct resource *res;
+        struct resource_entry *entry;
+
+        resource_list_for_each_entry(entry, &bridge->windows) {
+                res = entry->res;
+                if (res->parent &&
+                    (res->flags & (IORESOURCE_MEM | IORESOURCE_IO)))
+                        release_resource(res);
+        }
+        __acpi_pci_root_release_info(bridge->release_data);
+}
+
+struct pci_bus *acpi_pci_root_create(struct acpi_pci_root *root,
+                                     struct acpi_pci_root_ops *ops,
+                                     struct acpi_pci_root_info *info,
+                                     void *sysdata)
+{
+        int ret, busnum = root->secondary.start;
+        struct acpi_device *device = root->device;
+        int node = acpi_get_node(device->handle);
+        struct pci_bus *bus;
+
+        info->root = root;
+        info->bridge = device;
+        info->ops = ops;
+        INIT_LIST_HEAD(&info->resources);
+        snprintf(info->name, sizeof(info->name), "PCI Bus %04x:%02x",
+                 root->segment, busnum);
+
+        if (ops->init_info && ops->init_info(info))
+                goto out_release_info;
+        if (ops->prepare_resources)
+                ret = ops->prepare_resources(info);
+        else
+                ret = acpi_pci_probe_root_resources(info);
+        if (ret < 0)
+                goto out_release_info;
+
+        pci_acpi_root_add_resources(info);
+        pci_add_resource(&info->resources, &root->secondary);
+        bus = pci_create_root_bus(NULL, busnum, ops->pci_ops,
+                                  sysdata, &info->resources);
+        if (!bus)
+                goto out_release_info;
+
+        pci_scan_child_bus(bus);
+        pci_set_host_bridge_release(to_pci_host_bridge(bus->bridge),
+                                    acpi_pci_root_release_info, info);
+        if (node != NUMA_NO_NODE)
+                dev_printk(KERN_DEBUG, &bus->dev, "on NUMA node %d\n", node);
+        return bus;
+
+out_release_info:
+        __acpi_pci_root_release_info(info);
+        return NULL;
+}
+
 void __init acpi_pci_root_init(void)
 {
         acpi_hest_init();
diff --git a/include/linux/pci-acpi.h b/include/linux/pci-acpi.h
index a965efa52152..89ab0572dbc6 100644
--- a/include/linux/pci-acpi.h
+++ b/include/linux/pci-acpi.h
@@ -52,6 +52,30 @@ static inline acpi_handle acpi_pci_get_bridge_handle(struct pci_bus *pbus)
         return ACPI_HANDLE(dev);
 }
 
+struct acpi_pci_root;
+struct acpi_pci_root_ops;
+
+struct acpi_pci_root_info {
+        struct acpi_pci_root            *root;
+        struct acpi_device              *bridge;
+        struct acpi_pci_root_ops        *ops;
+        struct list_head                resources;
+        char                            name[16];
+};
+
+struct acpi_pci_root_ops {
+        struct pci_ops *pci_ops;
+        int (*init_info)(struct acpi_pci_root_info *info);
+        void (*release_info)(struct acpi_pci_root_info *info);
+        int (*prepare_resources)(struct acpi_pci_root_info *info);
+};
+
+extern int acpi_pci_probe_root_resources(struct acpi_pci_root_info *info);
+extern struct pci_bus *acpi_pci_root_create(struct acpi_pci_root *root,
+                                            struct acpi_pci_root_ops *ops,
+                                            struct acpi_pci_root_info *info,
+                                            void *sd);
+
 void acpi_pci_add_bus(struct pci_bus *bus);
 void acpi_pci_remove_bus(struct pci_bus *bus);