// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright IBM Corp. 2012
 *
 * Author(s):
 *   Jan Glauber <jang@linux.vnet.ibm.com>
 *
 * The System z PCI code is a rewrite from a prototype by
 * the following people (Kudoz!):
 *   Alexander Schmidt
 *   Christoph Raisch
 *   Hannes Hering
 *   Hoang-Nam Nguyen
 *   Jan-Bernd Themann
 *   Stefan Roscher
 *   Thomas Klein
 */

#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/isc.h>
#include <asm/airq.h>
#include <asm/facility.h>
#include <asm/pci_insn.h>
#include <asm/pci_clp.h>
#include <asm/pci_dma.h>

#include "pci_bus.h"
#include "pci_iov.h"

/* list of all detected zpci devices */
static LIST_HEAD(zpci_list);
static DEFINE_SPINLOCK(zpci_list_lock);

static DECLARE_BITMAP(zpci_domain, ZPCI_DOMAIN_BITMAP_SIZE);
static DEFINE_SPINLOCK(zpci_domain_lock);

#define ZPCI_IOMAP_ENTRIES                                              \
        min(((unsigned long) ZPCI_NR_DEVICES * PCI_STD_NUM_BARS / 2),   \
            ZPCI_IOMAP_MAX_ENTRIES)

unsigned int s390_pci_no_rid;

static DEFINE_SPINLOCK(zpci_iomap_lock);
static unsigned long *zpci_iomap_bitmap;
struct zpci_iomap_entry *zpci_iomap_start;
EXPORT_SYMBOL_GPL(zpci_iomap_start);

DEFINE_STATIC_KEY_FALSE(have_mio);

static struct kmem_cache *zdev_fmb_cache;

struct zpci_dev *get_zdev_by_fid(u32 fid)
{
        struct zpci_dev *tmp, *zdev = NULL;

        spin_lock(&zpci_list_lock);
        list_for_each_entry(tmp, &zpci_list, entry) {
                if (tmp->fid == fid) {
                        zdev = tmp;
                        break;
                }
        }
        spin_unlock(&zpci_list_lock);
        return zdev;
}

void zpci_remove_reserved_devices(void)
{
        struct zpci_dev *tmp, *zdev;
        enum zpci_state state;
        LIST_HEAD(remove);

        spin_lock(&zpci_list_lock);
        list_for_each_entry_safe(zdev, tmp, &zpci_list, entry) {
                if (zdev->state == ZPCI_FN_STATE_STANDBY &&
                    !clp_get_state(zdev->fid, &state) &&
                    state == ZPCI_FN_STATE_RESERVED)
                        list_move_tail(&zdev->entry, &remove);
        }
        spin_unlock(&zpci_list_lock);

        list_for_each_entry_safe(zdev, tmp, &remove, entry)
                zpci_device_reserved(zdev);
}

int pci_domain_nr(struct pci_bus *bus)
{
        return ((struct zpci_bus *) bus->sysdata)->domain_nr;
}
EXPORT_SYMBOL_GPL(pci_domain_nr);

int pci_proc_domain(struct pci_bus *bus)
{
        return pci_domain_nr(bus);
}
EXPORT_SYMBOL_GPL(pci_proc_domain);

/* Modify PCI: Register I/O address translation parameters */
int zpci_register_ioat(struct zpci_dev *zdev, u8 dmaas,
                       u64 base, u64 limit, u64 iota)
{
        u64 req = ZPCI_CREATE_REQ(zdev->fh, dmaas, ZPCI_MOD_FC_REG_IOAT);
        struct zpci_fib fib = {0};
        u8 cc, status;

        WARN_ON_ONCE(iota & 0x3fff);
        fib.pba = base;
        fib.pal = limit;
        fib.iota = iota | ZPCI_IOTA_RTTO_FLAG;
        cc = zpci_mod_fc(req, &fib, &status);
        if (cc)
                zpci_dbg(3, "reg ioat fid:%x, cc:%d, status:%d\n", zdev->fid, cc, status);
        return cc;
}

/* Modify PCI: Unregister I/O address translation parameters */
int zpci_unregister_ioat(struct zpci_dev *zdev, u8 dmaas)
{
        u64 req = ZPCI_CREATE_REQ(zdev->fh, dmaas, ZPCI_MOD_FC_DEREG_IOAT);
        struct zpci_fib fib = {0};
        u8 cc, status;

        cc = zpci_mod_fc(req, &fib, &status);
        if (cc)
                zpci_dbg(3, "unreg ioat fid:%x, cc:%d, status:%d\n", zdev->fid, cc, status);
        return cc;
}

/* Modify PCI: Set PCI function measurement parameters */
int zpci_fmb_enable_device(struct zpci_dev *zdev)
{
        u64 req = ZPCI_CREATE_REQ(zdev->fh, 0, ZPCI_MOD_FC_SET_MEASURE);
        struct zpci_fib fib = {0};
        u8 cc, status;

        if (zdev->fmb || sizeof(*zdev->fmb) < zdev->fmb_length)
                return -EINVAL;

        zdev->fmb = kmem_cache_zalloc(zdev_fmb_cache, GFP_KERNEL);
        if (!zdev->fmb)
                return -ENOMEM;
        WARN_ON((u64) zdev->fmb & 0xf);

        /* reset software counters */
        atomic64_set(&zdev->allocated_pages, 0);
        atomic64_set(&zdev->mapped_pages, 0);
        atomic64_set(&zdev->unmapped_pages, 0);

        fib.fmb_addr = virt_to_phys(zdev->fmb);
        cc = zpci_mod_fc(req, &fib, &status);
        if (cc) {
                kmem_cache_free(zdev_fmb_cache, zdev->fmb);
                zdev->fmb = NULL;
        }
        return cc ? -EIO : 0;
}

/* Modify PCI: Disable PCI function measurement */
int zpci_fmb_disable_device(struct zpci_dev *zdev)
{
        u64 req = ZPCI_CREATE_REQ(zdev->fh, 0, ZPCI_MOD_FC_SET_MEASURE);
        struct zpci_fib fib = {0};
        u8 cc, status;

        if (!zdev->fmb)
                return -EINVAL;

        /* Function measurement is disabled if fmb address is zero */
        cc = zpci_mod_fc(req, &fib, &status);
        if (cc == 3) /* Function already gone. */
                cc = 0;

        if (!cc) {
                kmem_cache_free(zdev_fmb_cache, zdev->fmb);
                zdev->fmb = NULL;
        }
        return cc ? -EIO : 0;
}

static int zpci_cfg_load(struct zpci_dev *zdev, int offset, u32 *val, u8 len)
{
        u64 req = ZPCI_CREATE_REQ(zdev->fh, ZPCI_PCIAS_CFGSPC, len);
        u64 data;
        int rc;

        rc = __zpci_load(&data, req, offset);
        if (!rc) {
                data = le64_to_cpu((__force __le64) data);
                data >>= (8 - len) * 8;
                *val = (u32) data;
        } else
                *val = 0xffffffff;
        return rc;
}

static int zpci_cfg_store(struct zpci_dev *zdev, int offset, u32 val, u8 len)
{
        u64 req = ZPCI_CREATE_REQ(zdev->fh, ZPCI_PCIAS_CFGSPC, len);
        u64 data = val;
        int rc;

        data <<= (8 - len) * 8;
        data = (__force u64) cpu_to_le64(data);
        rc = __zpci_store(data, req, offset);
        return rc;
}

resource_size_t pcibios_align_resource(void *data, const struct resource *res,
                                       resource_size_t size,
                                       resource_size_t align)
{
        return 0;
}

/* combine single writes by using store-block insn */
void __iowrite64_copy(void __iomem *to, const void *from, size_t count)
{
       zpci_memcpy_toio(to, from, count);
}

static void __iomem *__ioremap(phys_addr_t addr, size_t size, pgprot_t prot)
{
        unsigned long offset, vaddr;
        struct vm_struct *area;
        phys_addr_t last_addr;

        last_addr = addr + size - 1;
        if (!size || last_addr < addr)
                return NULL;

        if (!static_branch_unlikely(&have_mio))
                return (void __iomem *) addr;

        offset = addr & ~PAGE_MASK;
        addr &= PAGE_MASK;
        size = PAGE_ALIGN(size + offset);
        area = get_vm_area(size, VM_IOREMAP);
        if (!area)
                return NULL;

        vaddr = (unsigned long) area->addr;
        if (ioremap_page_range(vaddr, vaddr + size, addr, prot)) {
                free_vm_area(area);
                return NULL;
        }
        return (void __iomem *) ((unsigned long) area->addr + offset);
}

void __iomem *ioremap_prot(phys_addr_t addr, size_t size, unsigned long prot)
{
        return __ioremap(addr, size, __pgprot(prot));
}
EXPORT_SYMBOL(ioremap_prot);

void __iomem *ioremap(phys_addr_t addr, size_t size)
{
        return __ioremap(addr, size, PAGE_KERNEL);
}
EXPORT_SYMBOL(ioremap);

void __iomem *ioremap_wc(phys_addr_t addr, size_t size)
{
        return __ioremap(addr, size, pgprot_writecombine(PAGE_KERNEL));
}
EXPORT_SYMBOL(ioremap_wc);

void __iomem *ioremap_wt(phys_addr_t addr, size_t size)
{
        return __ioremap(addr, size, pgprot_writethrough(PAGE_KERNEL));
}
EXPORT_SYMBOL(ioremap_wt);

void iounmap(volatile void __iomem *addr)
{
        if (static_branch_likely(&have_mio))
                vunmap((__force void *) ((unsigned long) addr & PAGE_MASK));
}
EXPORT_SYMBOL(iounmap);

/* Create a virtual mapping cookie for a PCI BAR */
static void __iomem *pci_iomap_range_fh(struct pci_dev *pdev, int bar,
                                        unsigned long offset, unsigned long max)
{
        struct zpci_dev *zdev = to_zpci(pdev);
        int idx;

        idx = zdev->bars[bar].map_idx;
        spin_lock(&zpci_iomap_lock);
        /* Detect overrun */
        WARN_ON(!++zpci_iomap_start[idx].count);
        zpci_iomap_start[idx].fh = zdev->fh;
        zpci_iomap_start[idx].bar = bar;
        spin_unlock(&zpci_iomap_lock);

        return (void __iomem *) ZPCI_ADDR(idx) + offset;
}

static void __iomem *pci_iomap_range_mio(struct pci_dev *pdev, int bar,
                                         unsigned long offset,
                                         unsigned long max)
{
        unsigned long barsize = pci_resource_len(pdev, bar);
        struct zpci_dev *zdev = to_zpci(pdev);
        void __iomem *iova;

        iova = ioremap((unsigned long) zdev->bars[bar].mio_wt, barsize);
        return iova ? iova + offset : iova;
}

void __iomem *pci_iomap_range(struct pci_dev *pdev, int bar,
                              unsigned long offset, unsigned long max)
{
        if (bar >= PCI_STD_NUM_BARS || !pci_resource_len(pdev, bar))
                return NULL;

        if (static_branch_likely(&have_mio))
                return pci_iomap_range_mio(pdev, bar, offset, max);
        else
                return pci_iomap_range_fh(pdev, bar, offset, max);
}
EXPORT_SYMBOL(pci_iomap_range);

void __iomem *pci_iomap(struct pci_dev *dev, int bar, unsigned long maxlen)
{
        return pci_iomap_range(dev, bar, 0, maxlen);
}
EXPORT_SYMBOL(pci_iomap);

static void __iomem *pci_iomap_wc_range_mio(struct pci_dev *pdev, int bar,
                                            unsigned long offset, unsigned long max)
{
        unsigned long barsize = pci_resource_len(pdev, bar);
        struct zpci_dev *zdev = to_zpci(pdev);
        void __iomem *iova;

        iova = ioremap((unsigned long) zdev->bars[bar].mio_wb, barsize);
        return iova ? iova + offset : iova;
}

void __iomem *pci_iomap_wc_range(struct pci_dev *pdev, int bar,
                                 unsigned long offset, unsigned long max)
{
        if (bar >= PCI_STD_NUM_BARS || !pci_resource_len(pdev, bar))
                return NULL;

        if (static_branch_likely(&have_mio))
                return pci_iomap_wc_range_mio(pdev, bar, offset, max);
        else
                return pci_iomap_range_fh(pdev, bar, offset, max);
}
EXPORT_SYMBOL(pci_iomap_wc_range);

void __iomem *pci_iomap_wc(struct pci_dev *dev, int bar, unsigned long maxlen)
{
        return pci_iomap_wc_range(dev, bar, 0, maxlen);
}
EXPORT_SYMBOL(pci_iomap_wc);

static void pci_iounmap_fh(struct pci_dev *pdev, void __iomem *addr)
{
        unsigned int idx = ZPCI_IDX(addr);

        spin_lock(&zpci_iomap_lock);
        /* Detect underrun */
        WARN_ON(!zpci_iomap_start[idx].count);
        if (!--zpci_iomap_start[idx].count) {
                zpci_iomap_start[idx].fh = 0;
                zpci_iomap_start[idx].bar = 0;
        }
        spin_unlock(&zpci_iomap_lock);
}

static void pci_iounmap_mio(struct pci_dev *pdev, void __iomem *addr)
{
        iounmap(addr);
}

void pci_iounmap(struct pci_dev *pdev, void __iomem *addr)
{
        if (static_branch_likely(&have_mio))
                pci_iounmap_mio(pdev, addr);
        else
                pci_iounmap_fh(pdev, addr);
}
EXPORT_SYMBOL(pci_iounmap);

static int pci_read(struct pci_bus *bus, unsigned int devfn, int where,
                    int size, u32 *val)
{
        struct zpci_dev *zdev = get_zdev_by_bus(bus, devfn);

        return (zdev) ? zpci_cfg_load(zdev, where, val, size) : -ENODEV;
}

static int pci_write(struct pci_bus *bus, unsigned int devfn, int where,
                     int size, u32 val)
{
        struct zpci_dev *zdev = get_zdev_by_bus(bus, devfn);

        return (zdev) ? zpci_cfg_store(zdev, where, val, size) : -ENODEV;
}

static struct pci_ops pci_root_ops = {
        .read = pci_read,
        .write = pci_write,
};

static void zpci_map_resources(struct pci_dev *pdev)
{
        struct zpci_dev *zdev = to_zpci(pdev);
        resource_size_t len;
        int i;

        for (i = 0; i < PCI_STD_NUM_BARS; i++) {
                len = pci_resource_len(pdev, i);
                if (!len)
                        continue;

                if (zpci_use_mio(zdev))
                        pdev->resource[i].start =
                                (resource_size_t __force) zdev->bars[i].mio_wt;
                else
                        pdev->resource[i].start = (resource_size_t __force)
                                pci_iomap_range_fh(pdev, i, 0, 0);
                pdev->resource[i].end = pdev->resource[i].start + len - 1;
        }

        zpci_iov_map_resources(pdev);
}

static void zpci_unmap_resources(struct pci_dev *pdev)
{
        struct zpci_dev *zdev = to_zpci(pdev);
        resource_size_t len;
        int i;

        if (zpci_use_mio(zdev))
                return;

        for (i = 0; i < PCI_STD_NUM_BARS; i++) {
                len = pci_resource_len(pdev, i);
                if (!len)
                        continue;
                pci_iounmap_fh(pdev, (void __iomem __force *)
                               pdev->resource[i].start);
        }
}

static int zpci_alloc_iomap(struct zpci_dev *zdev)
{
        unsigned long entry;

        spin_lock(&zpci_iomap_lock);
        entry = find_first_zero_bit(zpci_iomap_bitmap, ZPCI_IOMAP_ENTRIES);
        if (entry == ZPCI_IOMAP_ENTRIES) {
                spin_unlock(&zpci_iomap_lock);
                return -ENOSPC;
        }
        set_bit(entry, zpci_iomap_bitmap);
        spin_unlock(&zpci_iomap_lock);
        return entry;
}

static void zpci_free_iomap(struct zpci_dev *zdev, int entry)
{
        spin_lock(&zpci_iomap_lock);
        memset(&zpci_iomap_start[entry], 0, sizeof(struct zpci_iomap_entry));
        clear_bit(entry, zpci_iomap_bitmap);
        spin_unlock(&zpci_iomap_lock);
}

static struct resource *__alloc_res(struct zpci_dev *zdev, unsigned long start,
                                    unsigned long size, unsigned long flags)
{
        struct resource *r;

        r = kzalloc(sizeof(*r), GFP_KERNEL);
        if (!r)
                return NULL;

        r->start = start;
        r->end = r->start + size - 1;
        r->flags = flags;
        r->name = zdev->res_name;

        if (request_resource(&iomem_resource, r)) {
                kfree(r);
                return NULL;
        }
        return r;
}

int zpci_setup_bus_resources(struct zpci_dev *zdev,
                             struct list_head *resources)
{
        unsigned long addr, size, flags;
        struct resource *res;
        int i, entry;

        snprintf(zdev->res_name, sizeof(zdev->res_name),
                 "PCI Bus %04x:%02x", zdev->uid, ZPCI_BUS_NR);

        for (i = 0; i < PCI_STD_NUM_BARS; i++) {
                if (!zdev->bars[i].size)
                        continue;
                entry = zpci_alloc_iomap(zdev);
                if (entry < 0)
                        return entry;
                zdev->bars[i].map_idx = entry;

                /* only MMIO is supported */
                flags = IORESOURCE_MEM;
                if (zdev->bars[i].val & 8)
                        flags |= IORESOURCE_PREFETCH;
                if (zdev->bars[i].val & 4)
                        flags |= IORESOURCE_MEM_64;

                if (zpci_use_mio(zdev))
                        addr = (unsigned long) zdev->bars[i].mio_wt;
                else
                        addr = ZPCI_ADDR(entry);
                size = 1UL << zdev->bars[i].size;

                res = __alloc_res(zdev, addr, size, flags);
                if (!res) {
                        zpci_free_iomap(zdev, entry);
                        return -ENOMEM;
                }
                zdev->bars[i].res = res;
                pci_add_resource(resources, res);
        }
        zdev->has_resources = 1;

        return 0;
}

static void zpci_cleanup_bus_resources(struct zpci_dev *zdev)
{
        int i;

        for (i = 0; i < PCI_STD_NUM_BARS; i++) {
                if (!zdev->bars[i].size || !zdev->bars[i].res)
                        continue;

                zpci_free_iomap(zdev, zdev->bars[i].map_idx);
                release_resource(zdev->bars[i].res);
                kfree(zdev->bars[i].res);
        }
        zdev->has_resources = 0;
}

int pcibios_add_device(struct pci_dev *pdev)
{
        struct zpci_dev *zdev = to_zpci(pdev);
        struct resource *res;
        int i;

        /* The pdev has a reference to the zdev via its bus */
        zpci_zdev_get(zdev);
        if (pdev->is_physfn)
                pdev->no_vf_scan = 1;

        pdev->dev.groups = zpci_attr_groups;
        pdev->dev.dma_ops = &s390_pci_dma_ops;
        zpci_map_resources(pdev);

        for (i = 0; i < PCI_STD_NUM_BARS; i++) {
                res = &pdev->resource[i];
                if (res->parent || !res->flags)
                        continue;
                pci_claim_resource(pdev, i);
        }

        return 0;
}

void pcibios_release_device(struct pci_dev *pdev)
{
        struct zpci_dev *zdev = to_zpci(pdev);

        zpci_unmap_resources(pdev);
        zpci_zdev_put(zdev);
}

int pcibios_enable_device(struct pci_dev *pdev, int mask)
{
        struct zpci_dev *zdev = to_zpci(pdev);

        zpci_debug_init_device(zdev, dev_name(&pdev->dev));
        zpci_fmb_enable_device(zdev);

        return pci_enable_resources(pdev, mask);
}

void pcibios_disable_device(struct pci_dev *pdev)
{
        struct zpci_dev *zdev = to_zpci(pdev);

        zpci_fmb_disable_device(zdev);
        zpci_debug_exit_device(zdev);
}

static int __zpci_register_domain(int domain)
{
        spin_lock(&zpci_domain_lock);
        if (test_bit(domain, zpci_domain)) {
                spin_unlock(&zpci_domain_lock);
                pr_err("Domain %04x is already assigned\n", domain);
                return -EEXIST;
        }
        set_bit(domain, zpci_domain);
        spin_unlock(&zpci_domain_lock);
        return domain;
}

static int __zpci_alloc_domain(void)
{
        int domain;

        spin_lock(&zpci_domain_lock);
        /*
         * We can always auto allocate domains below ZPCI_NR_DEVICES.
         * There is either a free domain or we have reached the maximum in
         * which case we would have bailed earlier.
         */
        domain = find_first_zero_bit(zpci_domain, ZPCI_NR_DEVICES);
        set_bit(domain, zpci_domain);
        spin_unlock(&zpci_domain_lock);
        return domain;
}

int zpci_alloc_domain(int domain)
{
        if (zpci_unique_uid) {
                if (domain)
                        return __zpci_register_domain(domain);
                pr_warn("UID checking was active but no UID is provided: switching to automatic domain allocation\n");
                update_uid_checking(false);
        }
        return __zpci_alloc_domain();
}

void zpci_free_domain(int domain)
{
        spin_lock(&zpci_domain_lock);
        clear_bit(domain, zpci_domain);
        spin_unlock(&zpci_domain_lock);
}


int zpci_enable_device(struct zpci_dev *zdev)
{
        u32 fh = zdev->fh;
        int rc = 0;

        if (clp_enable_fh(zdev, &fh, ZPCI_NR_DMA_SPACES))
                rc = -EIO;
        else
                zdev->fh = fh;
        return rc;
}

int zpci_disable_device(struct zpci_dev *zdev)
{
        u32 fh = zdev->fh;
        int cc, rc = 0;

        cc = clp_disable_fh(zdev, &fh);
        if (!cc) {
                zdev->fh = fh;
        } else if (cc == CLP_RC_SETPCIFN_ALRDY) {
                pr_info("Disabling PCI function %08x had no effect as it was already disabled\n",
                        zdev->fid);
                /* Function is already disabled - update handle */
                rc = clp_refresh_fh(zdev->fid, &fh);
                if (!rc) {
                        zdev->fh = fh;
                        rc = -EINVAL;
                }
        } else {
                rc = -EIO;
        }
        return rc;
}

/**
 * zpci_create_device() - Create a new zpci_dev and add it to the zbus
 * @fid: Function ID of the device to be created
 * @fh: Current Function Handle of the device to be created
 * @state: Initial state after creation either Standby or Configured
 *
 * Creates a new zpci device and adds it to its, possibly newly created, zbus
 * as well as zpci_list.
 *
 * Returns: the zdev on success or an error pointer otherwise
 */
struct zpci_dev *zpci_create_device(u32 fid, u32 fh, enum zpci_state state)
{
        struct zpci_dev *zdev;
        int rc;

        zpci_dbg(3, "add fid:%x, fh:%x, c:%d\n", fid, fh, state);
        zdev = kzalloc(sizeof(*zdev), GFP_KERNEL);
        if (!zdev)
                return ERR_PTR(-ENOMEM);

        /* FID and Function Handle are the static/dynamic identifiers */
        zdev->fid = fid;
        zdev->fh = fh;

        /* Query function properties and update zdev */
        rc = clp_query_pci_fn(zdev);
        if (rc)
                goto error;
        zdev->state =  state;

        kref_init(&zdev->kref);
        mutex_init(&zdev->lock);

        rc = zpci_init_iommu(zdev);
        if (rc)
                goto error;

        rc = zpci_bus_device_register(zdev, &pci_root_ops);
        if (rc)
                goto error_destroy_iommu;

        spin_lock(&zpci_list_lock);
        list_add_tail(&zdev->entry, &zpci_list);
        spin_unlock(&zpci_list_lock);

        return zdev;

error_destroy_iommu:
        zpci_destroy_iommu(zdev);
error:
        zpci_dbg(0, "add fid:%x, rc:%d\n", fid, rc);
        kfree(zdev);
        return ERR_PTR(rc);
}

bool zpci_is_device_configured(struct zpci_dev *zdev)
{
        enum zpci_state state = zdev->state;

        return state != ZPCI_FN_STATE_RESERVED &&
                state != ZPCI_FN_STATE_STANDBY;
}

/**
 * zpci_scan_configured_device() - Scan a freshly configured zpci_dev
 * @zdev: The zpci_dev to be configured
 * @fh: The general function handle supplied by the platform
 *
 * Given a device in the configuration state Configured, enables, scans and
 * adds it to the common code PCI subsystem if possible. If the PCI device is
 * parked because we can not yet create a PCI bus because we have not seen
 * function 0, it is ignored but will be scanned once function 0 appears.
 * If any failure occurs, the zpci_dev is left disabled.
 *
 * Return: 0 on success, or an error code otherwise
 */
int zpci_scan_configured_device(struct zpci_dev *zdev, u32 fh)
{
        int rc;

        zdev->fh = fh;
        /* the PCI function will be scanned once function 0 appears */
        if (!zdev->zbus->bus)
                return 0;

        /* For function 0 on a multi-function bus scan whole bus as we might
         * have to pick up existing functions waiting for it to allow creating
         * the PCI bus
         */
        if (zdev->devfn == 0 && zdev->zbus->multifunction)
                rc = zpci_bus_scan_bus(zdev->zbus);
        else
                rc = zpci_bus_scan_device(zdev);

        return rc;
}

/**
 * zpci_deconfigure_device() - Deconfigure a zpci_dev
 * @zdev: The zpci_dev to configure
 *
 * Deconfigure a zPCI function that is currently configured and possibly known
 * to the common code PCI subsystem.
 * If any failure occurs the device is left as is.
 *
 * Return: 0 on success, or an error code otherwise
 */
int zpci_deconfigure_device(struct zpci_dev *zdev)
{
        int rc;

        if (zdev->zbus->bus)
                zpci_bus_remove_device(zdev, false);

        if (zdev->dma_table) {
                rc = zpci_dma_exit_device(zdev);
                if (rc)
                        return rc;
        }
        if (zdev_enabled(zdev)) {
                rc = zpci_disable_device(zdev);
                if (rc)
                        return rc;
        }

        rc = sclp_pci_deconfigure(zdev->fid);
        zpci_dbg(3, "deconf fid:%x, rc:%d\n", zdev->fid, rc);
        if (rc)
                return rc;
        zdev->state = ZPCI_FN_STATE_STANDBY;

        return 0;
}

/**
 * zpci_device_reserved() - Mark device as resverved
 * @zdev: the zpci_dev that was reserved
 *
 * Handle the case that a given zPCI function was reserved by another system.
 * After a call to this function the zpci_dev can not be found via
 * get_zdev_by_fid() anymore but may still be accessible via existing
 * references though it will not be functional anymore.
 */
void zpci_device_reserved(struct zpci_dev *zdev)
{
        if (zdev->has_hp_slot)
                zpci_exit_slot(zdev);
        /*
         * Remove device from zpci_list as it is going away. This also
         * makes sure we ignore subsequent zPCI events for this device.
         */
        spin_lock(&zpci_list_lock);
        list_del(&zdev->entry);
        spin_unlock(&zpci_list_lock);
        zdev->state = ZPCI_FN_STATE_RESERVED;
        zpci_dbg(3, "rsv fid:%x\n", zdev->fid);
        zpci_zdev_put(zdev);
}

void zpci_release_device(struct kref *kref)
{
        struct zpci_dev *zdev = container_of(kref, struct zpci_dev, kref);
        int ret;

        if (zdev->zbus->bus)
                zpci_bus_remove_device(zdev, false);

        if (zdev->dma_table)
                zpci_dma_exit_device(zdev);
        if (zdev_enabled(zdev))
                zpci_disable_device(zdev);

        switch (zdev->state) {
        case ZPCI_FN_STATE_CONFIGURED:
                ret = sclp_pci_deconfigure(zdev->fid);
                zpci_dbg(3, "deconf fid:%x, rc:%d\n", zdev->fid, ret);
                fallthrough;
        case ZPCI_FN_STATE_STANDBY:
                if (zdev->has_hp_slot)
                        zpci_exit_slot(zdev);
                spin_lock(&zpci_list_lock);
                list_del(&zdev->entry);
                spin_unlock(&zpci_list_lock);
                zpci_dbg(3, "rsv fid:%x\n", zdev->fid);
                fallthrough;
        case ZPCI_FN_STATE_RESERVED:
                if (zdev->has_resources)
                        zpci_cleanup_bus_resources(zdev);
                zpci_bus_device_unregister(zdev);
                zpci_destroy_iommu(zdev);
                fallthrough;
        default:
                break;
        }
        zpci_dbg(3, "rem fid:%x\n", zdev->fid);
        kfree(zdev);
}

int zpci_report_error(struct pci_dev *pdev,
                      struct zpci_report_error_header *report)
{
        struct zpci_dev *zdev = to_zpci(pdev);

        return sclp_pci_report(report, zdev->fh, zdev->fid);
}
EXPORT_SYMBOL(zpci_report_error);

static int zpci_mem_init(void)
{
        BUILD_BUG_ON(!is_power_of_2(__alignof__(struct zpci_fmb)) ||
                     __alignof__(struct zpci_fmb) < sizeof(struct zpci_fmb));

        zdev_fmb_cache = kmem_cache_create("PCI_FMB_cache", sizeof(struct zpci_fmb),
                                           __alignof__(struct zpci_fmb), 0, NULL);
        if (!zdev_fmb_cache)
                goto error_fmb;

        zpci_iomap_start = kcalloc(ZPCI_IOMAP_ENTRIES,
                                   sizeof(*zpci_iomap_start), GFP_KERNEL);
        if (!zpci_iomap_start)
                goto error_iomap;

        zpci_iomap_bitmap = kcalloc(BITS_TO_LONGS(ZPCI_IOMAP_ENTRIES),
                                    sizeof(*zpci_iomap_bitmap), GFP_KERNEL);
        if (!zpci_iomap_bitmap)
                goto error_iomap_bitmap;

        if (static_branch_likely(&have_mio))
                clp_setup_writeback_mio();

        return 0;
error_iomap_bitmap:
        kfree(zpci_iomap_start);
error_iomap:
        kmem_cache_destroy(zdev_fmb_cache);
error_fmb:
        return -ENOMEM;
}

static void zpci_mem_exit(void)
{
        kfree(zpci_iomap_bitmap);
        kfree(zpci_iomap_start);
        kmem_cache_destroy(zdev_fmb_cache);
}

static unsigned int s390_pci_probe __initdata = 1;
unsigned int s390_pci_force_floating __initdata;
static unsigned int s390_pci_initialized;

char * __init pcibios_setup(char *str)
{
        if (!strcmp(str, "off")) {
                s390_pci_probe = 0;
                return NULL;
        }
        if (!strcmp(str, "nomio")) {
                S390_lowcore.machine_flags &= ~MACHINE_FLAG_PCI_MIO;
                return NULL;
        }
        if (!strcmp(str, "force_floating")) {
                s390_pci_force_floating = 1;
                return NULL;
        }
        if (!strcmp(str, "norid")) {
                s390_pci_no_rid = 1;
                return NULL;
        }
        return str;
}

bool zpci_is_enabled(void)
{
        return s390_pci_initialized;
}

static int __init pci_base_init(void)
{
        int rc;

        if (!s390_pci_probe)
                return 0;

        if (!test_facility(69) || !test_facility(71)) {
                pr_info("PCI is not supported because CPU facilities 69 or 71 are not available\n");
                return 0;
        }

        if (MACHINE_HAS_PCI_MIO) {
                static_branch_enable(&have_mio);
                ctl_set_bit(2, 5);
        }

        rc = zpci_debug_init();
        if (rc)
                goto out;

        rc = zpci_mem_init();
        if (rc)
                goto out_mem;

        rc = zpci_irq_init();

        if (rc)
                goto out_irq;

        rc = zpci_dma_init();
        if (rc)
                goto out_dma;

        rc = clp_scan_pci_devices();
        if (rc)
                goto out_find;
        zpci_bus_scan_busses();

        s390_pci_initialized = 1;
        return 0;

out_find:
        zpci_dma_exit();
out_dma:
        zpci_irq_exit();
out_irq:
        zpci_mem_exit();
out_mem:
        zpci_debug_exit();
out:
        return rc;
}
subsys_initcall_sync(pci_base_init);