// SPDX-License-Identifier: GPL-2.0
/*
* Copyright IBM Corp. 2020
*
* Author(s):
* Pierre Morel <[email protected]>
*
*/
#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;
}
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);
}
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