1 files changed, 147 insertions, 0 deletions
diff --git a/arch/s390/pci/pci_bus.c b/arch/s390/pci/pci_bus.c
new file mode 100644
index 000000000000..e1565b8537de
--- /dev/null
+++ b/arch/s390/pci/pci_bus.c
@@ -0,0 +1,147 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright IBM Corp. 2020
+ *
+ * Author(s):
+ *   Pierre Morel <pmorel@linux.ibm.com>
+ *
+ */
+
+#define KMSG_COMPONENT "zpci"
+#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
+
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/err.h>
+#include <linux/export.h>
+#include <linux/delay.h>
+#include <linux/seq_file.h>
+#include <linux/jump_label.h>
+#include <linux/pci.h>
+#include <linux/printk.h>
+
+#include <asm/pci_clp.h>
+#include <asm/pci_dma.h>
+
+#include "pci_bus.h"
+
+static LIST_HEAD(zbus_list);
+static DEFINE_SPINLOCK(zbus_list_lock);
+static int zpci_nb_devices;
+
+/* zpci_bus_scan
+ * @zbus: the zbus holding the zdevices
+ * @ops: the pci operations
+ *
+ * The domain number must be set before pci_scan_root_bus is called.
+ * This function can be called once the domain is known, hence
+ * when the function_0 is dicovered.
+ */
+static int zpci_bus_scan(struct zpci_bus *zbus, int domain, struct pci_ops *ops)
+{
+	struct pci_bus *bus;
+	int rc;
+
+	rc = zpci_alloc_domain(domain);
+	if (rc < 0)
+		return rc;
+	zbus->domain_nr = rc;
+
+	bus = pci_scan_root_bus(NULL, ZPCI_BUS_NR, ops, zbus, &zbus->resources);
+	if (!bus) {
+		zpci_free_domain(zbus->domain_nr);
+		return -EFAULT;
+	}
+
+	zbus->bus = bus;
+	pci_bus_add_devices(bus);
+	return 0;
+}
+
+static void zpci_bus_release(struct kref *kref)
+{
+	struct zpci_bus *zbus = container_of(kref, struct zpci_bus, kref);
+
+	pci_lock_rescan_remove();
+	pci_stop_root_bus(zbus->bus);
+
+	zpci_free_domain(zbus->domain_nr);
+	pci_free_resource_list(&zbus->resources);
+
+	pci_remove_root_bus(zbus->bus);
+	pci_unlock_rescan_remove();
+
+	spin_lock(&zbus_list_lock);
+	list_del(&zbus->bus_next);
+	spin_unlock(&zbus_list_lock);
+	kfree(zbus);
+}
+
+static void zpci_bus_put(struct zpci_bus *zbus)
+{
+	kref_put(&zbus->kref, zpci_bus_release);
+}
+
+static struct zpci_bus *zpci_bus_alloc(int pchid)
+{
+	struct zpci_bus *zbus;
+
+	zbus = kzalloc(sizeof(*zbus), GFP_KERNEL);
+	if (!zbus)
+		return NULL;
+
+	zbus->pchid = pchid;
+	INIT_LIST_HEAD(&zbus->bus_next);
+	spin_lock(&zbus_list_lock);
+	list_add_tail(&zbus->bus_next, &zbus_list);
+	spin_unlock(&zbus_list_lock);
+
+	kref_init(&zbus->kref);
+	INIT_LIST_HEAD(&zbus->resources);
+
+	return zbus;
+}
+
+int zpci_bus_device_register(struct zpci_dev *zdev, struct pci_ops *ops)
+{
+	struct zpci_bus *zbus;
+	int rc;
+
+	if (zpci_nb_devices == ZPCI_NR_DEVICES) {
+		pr_warn("Adding PCI function %08x failed because the configured limit of %d is reached\n",
+			zdev->fid, ZPCI_NR_DEVICES);
+		return -ENOSPC;
+	}
+	zpci_nb_devices++;
+
+	if (zdev->devfn != ZPCI_DEVFN)
+		return -EINVAL;
+
+	zbus = zpci_bus_alloc(zdev->pchid);
+	if (!zbus)
+		return -ENOMEM;
+
+	zdev->zbus = zbus;
+	zbus->function[ZPCI_DEVFN] = zdev;
+
+	zpci_setup_bus_resources(zdev, &zbus->resources);
+	zbus->max_bus_speed = zdev->max_bus_speed;
+
+	rc = zpci_bus_scan(zbus, (u16)zdev->uid, ops);
+	if (!rc)
+		return 0;
+
+	pr_err("Adding PCI function %08x failed\n", zdev->fid);
+	zdev->zbus = NULL;
+	zpci_bus_put(zbus);
+	return rc;
+}
+
+void zpci_bus_device_unregister(struct zpci_dev *zdev)
+{
+	struct zpci_bus *zbus = zdev->zbus;
+
+	zpci_nb_devices--;
+	zbus->function[ZPCI_DEVFN] = NULL;
+	zpci_bus_put(zbus);
+}