1 files changed, 379 insertions, 0 deletions

diff --git a/arch/s390/pci/pci_bus.c b/arch/s390/pci/pci_bus.c
new file mode 100644
index 000000000..32245b970
--- /dev/null
+++ b/arch/s390/pci/pci_bus.c
@@ -0,0 +1,379 @@
+// 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"
+#include "pci_iov.h"
+
+static LIST_HEAD(zbus_list);
+static DEFINE_MUTEX(zbus_list_lock);
+static int zpci_nb_devices;
+
+/* zpci_bus_prepare_device - Prepare a zPCI function for scanning
+ * @zdev: the zPCI function to be prepared
+ *
+ * The PCI resources for the function are set up and added to its zbus and the
+ * function is enabled. The function must be added to a zbus which must have
+ * a PCI bus created. If an error occurs the zPCI function is not enabled.
+ *
+ * Return: 0 on success, an error code otherwise
+ */
+static int zpci_bus_prepare_device(struct zpci_dev *zdev)
+{
+	int rc, i;
+
+	if (!zdev_enabled(zdev)) {
+		rc = zpci_enable_device(zdev);
+		if (rc)
+			return rc;
+		rc = zpci_dma_init_device(zdev);
+		if (rc) {
+			zpci_disable_device(zdev);
+			return rc;
+		}
+	}
+
+	if (!zdev->has_resources) {
+		zpci_setup_bus_resources(zdev);
+		for (i = 0; i < PCI_STD_NUM_BARS; i++) {
+			if (zdev->bars[i].res)
+				pci_bus_add_resource(zdev->zbus->bus, zdev->bars[i].res, 0);
+		}
+	}
+
+	return 0;
+}
+
+/* zpci_bus_scan_device - Scan a single device adding it to the PCI core
+ * @zdev: the zdev to be scanned
+ *
+ * Scans the PCI function making it available to the common PCI code.
+ *
+ * Return: 0 on success, an error value otherwise
+ */
+int zpci_bus_scan_device(struct zpci_dev *zdev)
+{
+	struct pci_dev *pdev;
+	int rc;
+
+	rc = zpci_bus_prepare_device(zdev);
+	if (rc)
+		return rc;
+
+	pdev = pci_scan_single_device(zdev->zbus->bus, zdev->devfn);
+	if (!pdev)
+		return -ENODEV;
+
+	pci_lock_rescan_remove();
+	pci_bus_add_device(pdev);
+	pci_unlock_rescan_remove();
+
+	return 0;
+}
+
+/* zpci_bus_remove_device - Removes the given zdev from the PCI core
+ * @zdev: the zdev to be removed from the PCI core
+ * @set_error: if true the device's error state is set to permanent failure
+ *
+ * Sets a zPCI device to a configured but offline state; the zPCI
+ * device is still accessible through its hotplug slot and the zPCI
+ * API but is removed from the common code PCI bus, making it
+ * no longer available to drivers.
+ */
+void zpci_bus_remove_device(struct zpci_dev *zdev, bool set_error)
+{
+	struct zpci_bus *zbus = zdev->zbus;
+	struct pci_dev *pdev;
+
+	if (!zdev->zbus->bus)
+		return;
+
+	pdev = pci_get_slot(zbus->bus, zdev->devfn);
+	if (pdev) {
+		if (set_error)
+			pdev->error_state = pci_channel_io_perm_failure;
+		if (pdev->is_virtfn) {
+			zpci_iov_remove_virtfn(pdev, zdev->vfn);
+			/* balance pci_get_slot */
+			pci_dev_put(pdev);
+			return;
+		}
+		pci_stop_and_remove_bus_device_locked(pdev);
+		/* balance pci_get_slot */
+		pci_dev_put(pdev);
+	}
+}
+
+/* zpci_bus_scan_bus - Scan all configured zPCI functions on the bus
+ * @zbus: the zbus to be scanned
+ *
+ * Enables and scans all PCI functions on the bus making them available to the
+ * common PCI code. If a PCI function fails to be initialized an error will be
+ * returned but attempts will still be made for all other functions on the bus.
+ *
+ * Return: 0 on success, an error value otherwise
+ */
+int zpci_bus_scan_bus(struct zpci_bus *zbus)
+{
+	struct zpci_dev *zdev;
+	int devfn, rc, ret = 0;
+
+	for (devfn = 0; devfn < ZPCI_FUNCTIONS_PER_BUS; devfn++) {
+		zdev = zbus->function[devfn];
+		if (zdev && zdev->state == ZPCI_FN_STATE_CONFIGURED) {
+			rc = zpci_bus_prepare_device(zdev);
+			if (rc)
+				ret = -EIO;
+		}
+	}
+
+	pci_lock_rescan_remove();
+	pci_scan_child_bus(zbus->bus);
+	pci_bus_add_devices(zbus->bus);
+	pci_unlock_rescan_remove();
+
+	return ret;
+}
+
+/* zpci_bus_scan_busses - Scan all registered busses
+ *
+ * Scan all available zbusses
+ *
+ */
+void zpci_bus_scan_busses(void)
+{
+	struct zpci_bus *zbus = NULL;
+
+	mutex_lock(&zbus_list_lock);
+	list_for_each_entry(zbus, &zbus_list, bus_next) {
+		zpci_bus_scan_bus(zbus);
+		cond_resched();
+	}
+	mutex_unlock(&zbus_list_lock);
+}
+
+/* zpci_bus_create_pci_bus - Create the PCI bus associated with this zbus
+ * @zbus: the zbus holding the zdevices
+ * @fr: PCI root function that will determine the bus's domain, and bus speeed
+ * @ops: the pci operations
+ *
+ * The PCI function @fr determines the domain (its UID), multifunction property
+ * and maximum bus speed of the entire bus.
+ *
+ * Return: 0 on success, an error code otherwise
+ */
+static int zpci_bus_create_pci_bus(struct zpci_bus *zbus, struct zpci_dev *fr, struct pci_ops *ops)
+{
+	struct pci_bus *bus;
+	int domain;
+
+	domain = zpci_alloc_domain((u16)fr->uid);
+	if (domain < 0)
+		return domain;
+
+	zbus->domain_nr = domain;
+	zbus->multifunction = fr->rid_available;
+	zbus->max_bus_speed = fr->max_bus_speed;
+
+	/*
+	 * Note that the zbus->resources are taken over and zbus->resources
+	 * is empty after a successful call
+	 */
+	bus = pci_create_root_bus(NULL, ZPCI_BUS_NR, ops, zbus, &zbus->resources);
+	if (!bus) {
+		zpci_free_domain(zbus->domain_nr);
+		return -EFAULT;
+	}
+
+	zbus->bus = bus;
+
+	return 0;
+}
+
+static void zpci_bus_release(struct kref *kref)
+{
+	struct zpci_bus *zbus = container_of(kref, struct zpci_bus, kref);
+
+	if (zbus->bus) {
+		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();
+	}
+
+	mutex_lock(&zbus_list_lock);
+	list_del(&zbus->bus_next);
+	mutex_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_get(int pchid)
+{
+	struct zpci_bus *zbus;
+
+	mutex_lock(&zbus_list_lock);
+	list_for_each_entry(zbus, &zbus_list, bus_next) {
+		if (pchid == zbus->pchid) {
+			kref_get(&zbus->kref);
+			goto out_unlock;
+		}
+	}
+	zbus = NULL;
+out_unlock:
+	mutex_unlock(&zbus_list_lock);
+	return zbus;
+}
+
+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);
+	mutex_lock(&zbus_list_lock);
+	list_add_tail(&zbus->bus_next, &zbus_list);
+	mutex_unlock(&zbus_list_lock);
+
+	kref_init(&zbus->kref);
+	INIT_LIST_HEAD(&zbus->resources);
+
+	zbus->bus_resource.start = 0;
+	zbus->bus_resource.end = ZPCI_BUS_NR;
+	zbus->bus_resource.flags = IORESOURCE_BUS;
+	pci_add_resource(&zbus->resources, &zbus->bus_resource);
+
+	return zbus;
+}
+
+void pcibios_bus_add_device(struct pci_dev *pdev)
+{
+	struct zpci_dev *zdev = to_zpci(pdev);
+
+	/*
+	 * With pdev->no_vf_scan the common PCI probing code does not
+	 * perform PF/VF linking.
+	 */
+	if (zdev->vfn) {
+		zpci_iov_setup_virtfn(zdev->zbus, pdev, zdev->vfn);
+		pdev->no_command_memory = 1;
+	}
+}
+
+static int zpci_bus_add_device(struct zpci_bus *zbus, struct zpci_dev *zdev)
+{
+	int rc = -EINVAL;
+
+	if (zbus->function[zdev->devfn]) {
+		pr_err("devfn %04x is already assigned\n", zdev->devfn);
+		return rc;
+	}
+
+	zdev->zbus = zbus;
+	zbus->function[zdev->devfn] = zdev;
+	zpci_nb_devices++;
+
+	if (zbus->multifunction && !zdev->rid_available) {
+		WARN_ONCE(1, "rid_available not set for multifunction\n");
+		goto error;
+	}
+	rc = zpci_init_slot(zdev);
+	if (rc)
+		goto error;
+	zdev->has_hp_slot = 1;
+
+	return 0;
+
+error:
+	zbus->function[zdev->devfn] = NULL;
+	zdev->zbus = NULL;
+	zpci_nb_devices--;
+	return rc;
+}
+
+int zpci_bus_device_register(struct zpci_dev *zdev, struct pci_ops *ops)
+{
+	struct zpci_bus *zbus = NULL;
+	int rc = -EBADF;
+
+	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;
+	}
+
+	if (zdev->devfn >= ZPCI_FUNCTIONS_PER_BUS)
+		return -EINVAL;
+
+	if (!s390_pci_no_rid && zdev->rid_available)
+		zbus = zpci_bus_get(zdev->pchid);
+
+	if (!zbus) {
+		zbus = zpci_bus_alloc(zdev->pchid);
+		if (!zbus)
+			return -ENOMEM;
+	}
+
+	if (!zbus->bus) {
+		/* The UID of the first PCI function registered with a zpci_bus
+		 * is used as the domain number for that bus. Currently there
+		 * is exactly one zpci_bus per domain.
+		 */
+		rc = zpci_bus_create_pci_bus(zbus, zdev, ops);
+		if (rc)
+			goto error;
+	}
+
+	rc = zpci_bus_add_device(zbus, zdev);
+	if (rc)
+		goto error;
+
+	return 0;
+
+error:
+	pr_err("Adding PCI function %08x failed\n", zdev->fid);
+	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[zdev->devfn] = NULL;
+	zpci_bus_put(zbus);
+}