// 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 pr_fmt(fmt) "zpci: " 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 <linux/lockdep.h>
#include <linux/list_sort.h>

#include <asm/machine.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 DEFINE_MUTEX(zpci_add_remove_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;

/* AEN structures that must be preserved over KVM module re-insertion */
union zpci_sic_iib *zpci_aipb;
EXPORT_SYMBOL_GPL(zpci_aipb);
struct airq_iv *zpci_aif_sbv;
EXPORT_SYMBOL_GPL(zpci_aif_sbv);

void zpci_zdev_put(struct zpci_dev *zdev)
{
        if (!zdev)
                return;
        mutex_lock(&zpci_add_remove_lock);
        kref_put_lock(&zdev->kref, zpci_release_device, &zpci_list_lock);
        mutex_unlock(&zpci_add_remove_lock);
}

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;
                        zpci_zdev_get(zdev);
                        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, u8 *status)
{
        u64 req = ZPCI_CREATE_REQ(zdev->fh, dmaas, ZPCI_MOD_FC_REG_IOAT);
        struct zpci_fib fib = {0};
        u8 cc;

        fib.pba = base;
        /* Work around off by one in ISM virt device */
        if (zdev->pft == PCI_FUNC_TYPE_ISM && limit > base)
                fib.pal = limit + (1 << 12);
        else
                fib.pal = limit;
        fib.iota = iota;
        fib.gd = zdev->gisa;
        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;
}
EXPORT_SYMBOL_GPL(zpci_register_ioat);

/* 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;

        fib.gd = zdev->gisa;

        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_iommu_ctrs *ctrs;
        struct zpci_fib fib = {0};
        unsigned long flags;
        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 */
        spin_lock_irqsave(&zdev->dom_lock, flags);
        ctrs = zpci_get_iommu_ctrs(zdev);
        if (ctrs) {
                atomic64_set(&ctrs->mapped_pages, 0);
                atomic64_set(&ctrs->unmapped_pages, 0);
                atomic64_set(&ctrs->global_rpcits, 0);
                atomic64_set(&ctrs->sync_map_rpcits, 0);
                atomic64_set(&ctrs->sync_rpcits, 0);
        }
        spin_unlock_irqrestore(&zdev->dom_lock, flags);


        fib.fmb_addr = virt_to_phys(zdev->fmb);
        fib.gd = zdev->gisa;
        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;

        fib.gd = zdev->gisa;

        /* 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);
        int rc = -ENODEV;
        u64 data;

        if (!zdev_enabled(zdev))
                goto out_err;

        rc = __zpci_load(&data, req, offset);
        if (rc)
                goto out_err;
        data = le64_to_cpu((__force __le64)data);
        data >>= (8 - len) * 8;
        *val = (u32)data;
        return 0;

out_err:
        PCI_SET_ERROR_RESPONSE(val);
        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);
        int rc = -ENODEV;
        u64 data = val;

        if (!zdev_enabled(zdev))
                return 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;
}

void __iomem *ioremap_prot(phys_addr_t phys_addr, size_t size,
                           pgprot_t prot)
{
        /*
         * When PCI MIO instructions are unavailable the "physical" address
         * encodes a hint for accessing the PCI memory space it represents.
         * Just pass it unchanged such that ioread/iowrite can decode it.
         */
        if (!static_branch_unlikely(&have_mio))
                return (void __iomem *)phys_addr;

        return generic_ioremap_prot(phys_addr, size, prot);
}
EXPORT_SYMBOL(ioremap_prot);

void iounmap(volatile void __iomem *addr)
{
        if (static_branch_likely(&have_mio))
                generic_iounmap(addr);
}
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 = zdev_from_bus(bus, devfn);

        if (!zdev || zpci_cfg_load(zdev, where, val, size))
                return PCIBIOS_DEVICE_NOT_FOUND;
        return PCIBIOS_SUCCESSFUL;
}

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

        if (!zdev || zpci_cfg_store(zdev, where, val, size))
                return PCIBIOS_DEVICE_NOT_FOUND;
        return PCIBIOS_SUCCESSFUL;
}

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 void zpci_do_update_iomap_fh(struct zpci_dev *zdev, u32 fh)
{
        int bar, idx;

        spin_lock(&zpci_iomap_lock);
        for (bar = 0; bar < PCI_STD_NUM_BARS; bar++) {
                if (!zdev->bars[bar].size)
                        continue;
                idx = zdev->bars[bar].map_idx;
                if (!zpci_iomap_start[idx].count)
                        continue;
                WRITE_ONCE(zpci_iomap_start[idx].fh, zdev->fh);
        }
        spin_unlock(&zpci_iomap_lock);
}

void zpci_update_fh(struct zpci_dev *zdev, u32 fh)
{
        if (!fh || zdev->fh == fh)
                return;

        zdev->fh = fh;
        if (zpci_use_mio(zdev))
                return;
        if (zdev->has_resources && zdev_enabled(zdev))
                zpci_do_update_iomap_fh(zdev, fh);
}

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

        r = kzalloc_obj(*r);
        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)
{
        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;
        }
        zdev->has_resources = 1;

        return 0;
}

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

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

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

int pcibios_device_add(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;

        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
                zpci_update_fh(zdev, fh);
        return rc;
}
EXPORT_SYMBOL_GPL(zpci_enable_device);

int zpci_reenable_device(struct zpci_dev *zdev)
{
        u8 status;
        int rc;

        rc = zpci_enable_device(zdev);
        if (rc)
                return rc;

        if (zdev->msi_nr_irqs > 0) {
                rc = zpci_set_irq(zdev);
                if (rc)
                        return rc;
        }

        rc = zpci_iommu_register_ioat(zdev, &status);
        if (rc)
                zpci_disable_device(zdev);

        return rc;
}
EXPORT_SYMBOL_GPL(zpci_reenable_device);

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

        cc = clp_disable_fh(zdev, &fh);
        if (!cc) {
                zpci_update_fh(zdev, 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) {
                        zpci_update_fh(zdev, fh);
                        rc = -EINVAL;
                }
        } else {
                rc = -EIO;
        }
        return rc;
}
EXPORT_SYMBOL_GPL(zpci_disable_device);

/**
 * zpci_hot_reset_device - perform a reset of the given zPCI function
 * @zdev: the slot which should be reset
 *
 * Performs a low level reset of the zPCI function. The reset is low level in
 * the sense that the zPCI function can be reset without detaching it from the
 * common PCI subsystem. The reset may be performed while under control of
 * either DMA or IOMMU APIs in which case the existing DMA/IOMMU translation
 * table is reinstated at the end of the reset.
 *
 * After the reset the functions internal state is reset to an initial state
 * equivalent to its state during boot when first probing a driver.
 * Consequently after reset the PCI function requires re-initialization via the
 * common PCI code including re-enabling IRQs via pci_alloc_irq_vectors()
 * and enabling the function via e.g. pci_enable_device_flags(). The caller
 * must guard against concurrent reset attempts.
 *
 * In most cases this function should not be called directly but through
 * pci_reset_function() or pci_reset_bus() which handle the save/restore and
 * locking - asserted by lockdep.
 *
 * Return: 0 on success and an error value otherwise
 */
int zpci_hot_reset_device(struct zpci_dev *zdev)
{
        int rc;

        lockdep_assert_held(&zdev->state_lock);
        zpci_dbg(3, "rst fid:%x, fh:%x\n", zdev->fid, zdev->fh);
        if (zdev_enabled(zdev)) {
                /* Disables device access, DMAs and IRQs (reset state) */
                rc = zpci_disable_device(zdev);
                /*
                 * Due to a z/VM vs LPAR inconsistency in the error state the
                 * FH may indicate an enabled device but disable says the
                 * device is already disabled don't treat it as an error here.
                 */
                if (rc == -EINVAL)
                        rc = 0;
                if (rc)
                        return rc;
        }

        rc = zpci_reenable_device(zdev);

        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
 *
 * Allocates a new struct zpci_dev and queries the platform for its details.
 * If successful the device can subsequently be added to the zPCI subsystem
 * using zpci_add_device().
 *
 * 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;

        zdev = kzalloc_obj(*zdev);
        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;

        mutex_init(&zdev->state_lock);
        mutex_init(&zdev->fmb_lock);
        mutex_init(&zdev->kzdev_lock);

        return zdev;

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

/**
 * zpci_add_device() - Add a previously created zPCI device to the zPCI subsystem
 * @zdev: The zPCI device to be added
 *
 * A struct zpci_dev is added to the zPCI subsystem and to a virtual PCI bus creating
 * a new one as necessary. A hotplug slot is created and events start to be handled.
 * If successful from this point on zpci_zdev_get() and zpci_zdev_put() must be used.
 * If adding the struct zpci_dev fails the device was not added and should be freed.
 *
 * Return: 0 on success, or an error code otherwise
 */
int zpci_add_device(struct zpci_dev *zdev)
{
        int rc;

        mutex_lock(&zpci_add_remove_lock);
        zpci_dbg(1, "add fid:%x, fh:%x, c:%d\n", zdev->fid, zdev->fh, zdev->state);
        rc = zpci_init_iommu(zdev);
        if (rc)
                goto error;

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

        kref_init(&zdev->kref);
        spin_lock(&zpci_list_lock);
        list_add_tail(&zdev->entry, &zpci_list);
        spin_unlock(&zpci_list_lock);
        mutex_unlock(&zpci_add_remove_lock);
        return 0;

error_destroy_iommu:
        zpci_destroy_iommu(zdev);
error:
        zpci_dbg(0, "add fid:%x, rc:%d\n", zdev->fid, rc);
        mutex_unlock(&zpci_add_remove_lock);
        return 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 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)
{
        zpci_update_fh(zdev, fh);
        return zpci_bus_scan_device(zdev);
}

/**
 * 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;

        lockdep_assert_held(&zdev->state_lock);
        if (zdev->state != ZPCI_FN_STATE_CONFIGURED)
                return 0;

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

        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 reserved
 * @zdev: the zpci_dev that was reserved
 *
 * Handle the case that a given zPCI function was reserved by another system.
 */
void zpci_device_reserved(struct zpci_dev *zdev)
{
        lockdep_assert_held(&zdev->state_lock);
        /* We may declare the device reserved multiple times */
        if (zdev->state == ZPCI_FN_STATE_RESERVED)
                return;
        zdev->state = ZPCI_FN_STATE_RESERVED;
        zpci_dbg(3, "rsv fid:%x\n", zdev->fid);
        /*
         * The underlying device is gone. Allow the zdev to be freed
         * as soon as all other references are gone by accounting for
         * the removal as a dropped reference.
         */
        zpci_zdev_put(zdev);
}

void zpci_release_device(struct kref *kref)
        __releases(&zpci_list_lock)
{
        struct zpci_dev *zdev = container_of(kref, struct zpci_dev, kref);

        lockdep_assert_held(&zpci_add_remove_lock);
        WARN_ON(zdev->state != ZPCI_FN_STATE_RESERVED);
        /*
         * We already hold zpci_list_lock thanks to kref_put_lock().
         * This makes sure no new reference can be taken from the list.
         */
        list_del(&zdev->entry);
        spin_unlock(&zpci_list_lock);

        if (zdev->has_hp_slot)
                zpci_exit_slot(zdev);

        if (zdev->has_resources)
                zpci_cleanup_bus_resources(zdev);

        zpci_bus_device_unregister(zdev);
        zpci_destroy_iommu(zdev);
        zpci_dbg(3, "rem fid:%x\n", zdev->fid);
        kfree_rcu(zdev, rcu);
}

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);

/**
 * zpci_clear_error_state() - Clears the zPCI error state of the device
 * @zdev: The zdev for which the zPCI error state should be reset
 *
 * Clear the zPCI error state of the device. If clearing the zPCI error state
 * fails the device is left in the error state. In this case it may make sense
 * to call zpci_io_perm_failure() on the associated pdev if it exists.
 *
 * Returns: 0 on success, -EIO otherwise
 */
int zpci_clear_error_state(struct zpci_dev *zdev)
{
        u64 req = ZPCI_CREATE_REQ(zdev->fh, 0, ZPCI_MOD_FC_RESET_ERROR);
        struct zpci_fib fib = {0};
        u8 status;
        int cc;

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

        return 0;
}

/**
 * zpci_reset_load_store_blocked() - Re-enables L/S from error state
 * @zdev: The zdev for which to unblock load/store access
 *
 * Re-enables load/store access for a PCI function in the error state while
 * keeping DMA blocked. In this state drivers can poke MMIO space to determine
 * if error recovery is possible while catching any rogue DMA access from the
 * device.
 *
 * Returns: 0 on success, -EIO otherwise
 */
int zpci_reset_load_store_blocked(struct zpci_dev *zdev)
{
        u64 req = ZPCI_CREATE_REQ(zdev->fh, 0, ZPCI_MOD_FC_RESET_BLOCK);
        struct zpci_fib fib = {0};
        u8 status;
        int cc;

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

        return 0;
}

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));
        BUILD_BUG_ON((CONFIG_ILLEGAL_POINTER_VALUE + 0x10000 > ZPCI_IOMAP_ADDR_BASE) &&
                     (CONFIG_ILLEGAL_POINTER_VALUE <= ZPCI_IOMAP_ADDR_MAX));

        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 = kzalloc_objs(*zpci_iomap_start, ZPCI_IOMAP_ENTRIES);
        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")) {
                clear_machine_feature(MFEATURE_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 zpci_cmp_rid(void *priv, const struct list_head *a,
                        const struct list_head *b)
{
        struct zpci_dev *za = container_of(a, struct zpci_dev, entry);
        struct zpci_dev *zb = container_of(b, struct zpci_dev, entry);

        /*
         * PCI functions without RID available maintain original order
         * between themselves but sort before those with RID.
         */
        if (za->rid == zb->rid)
                return za->rid_available > zb->rid_available;
        /*
         * PCI functions with RID sort by RID ascending.
         */
        return za->rid > zb->rid;
}

static void zpci_add_devices(struct list_head *scan_list)
{
        struct zpci_dev *zdev, *tmp;

        list_sort(NULL, scan_list, &zpci_cmp_rid);
        list_for_each_entry_safe(zdev, tmp, scan_list, entry) {
                list_del_init(&zdev->entry);
                if (zpci_add_device(zdev))
                        kfree(zdev);
        }
}

int zpci_scan_devices(void)
{
        struct zpci_bus *zbus;
        LIST_HEAD(scan_list);
        int rc;

        rc = clp_scan_pci_devices(&scan_list);
        if (rc)
                return rc;

        zpci_add_devices(&scan_list);
        zpci_bus_for_each(zbus) {
                zpci_bus_scan_bus(zbus);
                cond_resched();
        }
        return 0;
}

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 (test_machine_feature(MFEATURE_PCI_MIO)) {
                static_branch_enable(&have_mio);
                system_ctl_set_bit(2, CR2_MIO_ADDRESSING_BIT);
        }

        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_scan_devices();
        if (rc)
                goto out_find;

        rc = zpci_fw_sysfs_init();
        if (rc)
                goto out_find;

        s390_pci_initialized = 1;
        return 0;

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