// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * pci_dn.c
 *
 * Copyright (C) 2001 Todd Inglett, IBM Corporation
 *
 * PCI manipulation via device_nodes.
 */
#include <linux/kernel.h>
#include <linux/pci.h>
#include <linux/string.h>
#include <linux/export.h>
#include <linux/init.h>
#include <linux/gfp.h>

#include <asm/io.h>
#include <asm/prom.h>
#include <asm/pci-bridge.h>
#include <asm/ppc-pci.h>
#include <asm/firmware.h>
#include <asm/eeh.h>

/*
 * The function is used to find the firmware data of one
 * specific PCI device, which is attached to the indicated
 * PCI bus. For VFs, their firmware data is linked to that
 * one of PF's bridge. For other devices, their firmware
 * data is linked to that of their bridge.
 */
static struct pci_dn *pci_bus_to_pdn(struct pci_bus *bus)
{
        struct pci_bus *pbus;
        struct device_node *dn;
        struct pci_dn *pdn;

        /*
         * We probably have virtual bus which doesn't
         * have associated bridge.
         */
        pbus = bus;
        while (pbus) {
                if (pci_is_root_bus(pbus) || pbus->self)
                        break;

                pbus = pbus->parent;
        }

        /*
         * Except virtual bus, all PCI buses should
         * have device nodes.
         */
        dn = pci_bus_to_OF_node(pbus);
        pdn = dn ? PCI_DN(dn) : NULL;

        return pdn;
}

struct pci_dn *pci_get_pdn_by_devfn(struct pci_bus *bus,
                                    int devfn)
{
        struct device_node *dn = NULL;
        struct pci_dn *parent, *pdn;
        struct pci_dev *pdev = NULL;

        /* Fast path: fetch from PCI device */
        list_for_each_entry(pdev, &bus->devices, bus_list) {
                if (pdev->devfn == devfn) {
                        if (pdev->dev.archdata.pci_data)
                                return pdev->dev.archdata.pci_data;

                        dn = pci_device_to_OF_node(pdev);
                        break;
                }
        }

        /* Fast path: fetch from device node */
        pdn = dn ? PCI_DN(dn) : NULL;
        if (pdn)
                return pdn;

        /* Slow path: fetch from firmware data hierarchy */
        parent = pci_bus_to_pdn(bus);
        if (!parent)
                return NULL;

        list_for_each_entry(pdn, &parent->child_list, list) {
                if (pdn->busno == bus->number &&
                    pdn->devfn == devfn)
                        return pdn;
        }

        return NULL;
}

struct pci_dn *pci_get_pdn(struct pci_dev *pdev)
{
        struct device_node *dn;
        struct pci_dn *parent, *pdn;

        /* Search device directly */
        if (pdev->dev.archdata.pci_data)
                return pdev->dev.archdata.pci_data;

        /* Check device node */
        dn = pci_device_to_OF_node(pdev);
        pdn = dn ? PCI_DN(dn) : NULL;
        if (pdn)
                return pdn;

        /*
         * VFs don't have device nodes. We hook their
         * firmware data to PF's bridge.
         */
        parent = pci_bus_to_pdn(pdev->bus);
        if (!parent)
                return NULL;

        list_for_each_entry(pdn, &parent->child_list, list) {
                if (pdn->busno == pdev->bus->number &&
                    pdn->devfn == pdev->devfn)
                        return pdn;
        }

        return NULL;
}

#ifdef CONFIG_EEH
static struct eeh_dev *eeh_dev_init(struct pci_dn *pdn)
{
        struct eeh_dev *edev;

        /* Allocate EEH device */
        edev = kzalloc(sizeof(*edev), GFP_KERNEL);
        if (!edev)
                return NULL;

        /* Associate EEH device with OF node */
        pdn->edev = edev;
        edev->pdn = pdn;
        edev->bdfn = (pdn->busno << 8) | pdn->devfn;
        edev->controller = pdn->phb;

        return edev;
}
#endif /* CONFIG_EEH */

#ifdef CONFIG_PCI_IOV
static struct pci_dn *add_one_sriov_vf_pdn(struct pci_dn *parent,
                                           int busno, int devfn)
{
        struct pci_dn *pdn;

        /* Except PHB, we always have the parent */
        if (!parent)
                return NULL;

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

        pdn->phb = parent->phb;
        pdn->parent = parent;
        pdn->busno = busno;
        pdn->devfn = devfn;
        pdn->pe_number = IODA_INVALID_PE;
        INIT_LIST_HEAD(&pdn->child_list);
        INIT_LIST_HEAD(&pdn->list);
        list_add_tail(&pdn->list, &parent->child_list);

        return pdn;
}

struct pci_dn *add_sriov_vf_pdns(struct pci_dev *pdev)
{
        struct pci_dn *parent, *pdn;
        int i;

        /* Only support IOV for now */
        if (WARN_ON(!pdev->is_physfn))
                return NULL;

        /* Check if VFs have been populated */
        pdn = pci_get_pdn(pdev);
        if (!pdn || (pdn->flags & PCI_DN_FLAG_IOV_VF))
                return NULL;

        pdn->flags |= PCI_DN_FLAG_IOV_VF;
        parent = pci_bus_to_pdn(pdev->bus);
        if (!parent)
                return NULL;

        for (i = 0; i < pci_sriov_get_totalvfs(pdev); i++) {
                struct eeh_dev *edev __maybe_unused;

                pdn = add_one_sriov_vf_pdn(parent,
                                           pci_iov_virtfn_bus(pdev, i),
                                           pci_iov_virtfn_devfn(pdev, i));
                if (!pdn) {
                        dev_warn(&pdev->dev, "%s: Cannot create firmware data for VF#%d\n",
                                 __func__, i);
                        return NULL;
                }

#ifdef CONFIG_EEH
                /* Create the EEH device for the VF */
                edev = eeh_dev_init(pdn);
                BUG_ON(!edev);

                /* FIXME: these should probably be populated by the EEH probe */
                edev->physfn = pdev;
                edev->vf_index = i;
#endif /* CONFIG_EEH */
        }
        return pci_get_pdn(pdev);
}

void remove_sriov_vf_pdns(struct pci_dev *pdev)
{
        struct pci_dn *parent;
        struct pci_dn *pdn, *tmp;
        int i;

        /* Only support IOV PF for now */
        if (WARN_ON(!pdev->is_physfn))
                return;

        /* Check if VFs have been populated */
        pdn = pci_get_pdn(pdev);
        if (!pdn || !(pdn->flags & PCI_DN_FLAG_IOV_VF))
                return;

        pdn->flags &= ~PCI_DN_FLAG_IOV_VF;
        parent = pci_bus_to_pdn(pdev->bus);
        if (!parent)
                return;

        /*
         * We might introduce flag to pci_dn in future
         * so that we can release VF's firmware data in
         * a batch mode.
         */
        for (i = 0; i < pci_sriov_get_totalvfs(pdev); i++) {
                struct eeh_dev *edev __maybe_unused;

                list_for_each_entry_safe(pdn, tmp,
                        &parent->child_list, list) {
                        if (pdn->busno != pci_iov_virtfn_bus(pdev, i) ||
                            pdn->devfn != pci_iov_virtfn_devfn(pdev, i))
                                continue;

#ifdef CONFIG_EEH
                        /*
                         * Release EEH state for this VF. The PCI core
                         * has already torn down the pci_dev for this VF, but
                         * we're responsible to removing the eeh_dev since it
                         * has the same lifetime as the pci_dn that spawned it.
                         */
                        edev = pdn_to_eeh_dev(pdn);
                        if (edev) {
                                /*
                                 * We allocate pci_dn's for the totalvfs count,
                                 * but only only the vfs that were activated
                                 * have a configured PE.
                                 */
                                if (edev->pe)
                                        eeh_pe_tree_remove(edev);

                                pdn->edev = NULL;
                                kfree(edev);
                        }
#endif /* CONFIG_EEH */

                        if (!list_empty(&pdn->list))
                                list_del(&pdn->list);

                        kfree(pdn);
                }
        }
}
#endif /* CONFIG_PCI_IOV */

struct pci_dn *pci_add_device_node_info(struct pci_controller *hose,
                                        struct device_node *dn)
{
        const __be32 *type = of_get_property(dn, "ibm,pci-config-space-type", NULL);
        const __be32 *regs;
        struct device_node *parent;
        struct pci_dn *pdn;
#ifdef CONFIG_EEH
        struct eeh_dev *edev;
#endif

        pdn = kzalloc(sizeof(*pdn), GFP_KERNEL);
        if (pdn == NULL)
                return NULL;
        dn->data = pdn;
        pdn->phb = hose;
        pdn->pe_number = IODA_INVALID_PE;
        regs = of_get_property(dn, "reg", NULL);
        if (regs) {
                u32 addr = of_read_number(regs, 1);

                /* First register entry is addr (00BBSS00)  */
                pdn->busno = (addr >> 16) & 0xff;
                pdn->devfn = (addr >> 8) & 0xff;
        }

        /* vendor/device IDs and class code */
        regs = of_get_property(dn, "vendor-id", NULL);
        pdn->vendor_id = regs ? of_read_number(regs, 1) : 0;
        regs = of_get_property(dn, "device-id", NULL);
        pdn->device_id = regs ? of_read_number(regs, 1) : 0;
        regs = of_get_property(dn, "class-code", NULL);
        pdn->class_code = regs ? of_read_number(regs, 1) : 0;

        /* Extended config space */
        pdn->pci_ext_config_space = (type && of_read_number(type, 1) == 1);

        /* Create EEH device */
#ifdef CONFIG_EEH
        edev = eeh_dev_init(pdn);
        if (!edev) {
                kfree(pdn);
                return NULL;
        }
#endif

        /* Attach to parent node */
        INIT_LIST_HEAD(&pdn->child_list);
        INIT_LIST_HEAD(&pdn->list);
        parent = of_get_parent(dn);
        pdn->parent = parent ? PCI_DN(parent) : NULL;
        if (pdn->parent)
                list_add_tail(&pdn->list, &pdn->parent->child_list);

        return pdn;
}
EXPORT_SYMBOL_GPL(pci_add_device_node_info);

void pci_remove_device_node_info(struct device_node *dn)
{
        struct pci_dn *pdn = dn ? PCI_DN(dn) : NULL;
        struct device_node *parent;
        struct pci_dev *pdev;
#ifdef CONFIG_EEH
        struct eeh_dev *edev = pdn_to_eeh_dev(pdn);

        if (edev)
                edev->pdn = NULL;
#endif

        if (!pdn)
                return;

        WARN_ON(!list_empty(&pdn->child_list));
        list_del(&pdn->list);

        /* Drop the parent pci_dn's ref to our backing dt node */
        parent = of_get_parent(dn);
        if (parent)
                of_node_put(parent);

        /*
         * At this point we *might* still have a pci_dev that was
         * instantiated from this pci_dn. So defer free()ing it until
         * the pci_dev's release function is called.
         */
        pdev = pci_get_domain_bus_and_slot(pdn->phb->global_number,
                        pdn->busno, pdn->devfn);
        if (pdev) {
                /* NB: pdev has a ref to dn */
                pci_dbg(pdev, "marked pdn (from %pOF) as dead\n", dn);
                pdn->flags |= PCI_DN_FLAG_DEAD;
        } else {
                dn->data = NULL;
                kfree(pdn);
        }

        pci_dev_put(pdev);
}
EXPORT_SYMBOL_GPL(pci_remove_device_node_info);

/*
 * Traverse a device tree stopping each PCI device in the tree.
 * This is done depth first.  As each node is processed, a "pre"
 * function is called and the children are processed recursively.
 *
 * The "pre" func returns a value.  If non-zero is returned from
 * the "pre" func, the traversal stops and this value is returned.
 * This return value is useful when using traverse as a method of
 * finding a device.
 *
 * NOTE: we do not run the func for devices that do not appear to
 * be PCI except for the start node which we assume (this is good
 * because the start node is often a phb which may be missing PCI
 * properties).
 * We use the class-code as an indicator. If we run into
 * one of these nodes we also assume its siblings are non-pci for
 * performance.
 */
void *pci_traverse_device_nodes(struct device_node *start,
                                void *(*fn)(struct device_node *, void *),
                                void *data)
{
        struct device_node *dn, *nextdn;
        void *ret;

        /* We started with a phb, iterate all childs */
        for (dn = start->child; dn; dn = nextdn) {
                const __be32 *classp;
                u32 class = 0;

                nextdn = NULL;
                classp = of_get_property(dn, "class-code", NULL);
                if (classp)
                        class = of_read_number(classp, 1);

                if (fn) {
                        ret = fn(dn, data);
                        if (ret)
                                return ret;
                }

                /* If we are a PCI bridge, go down */
                if (dn->child && ((class >> 8) == PCI_CLASS_BRIDGE_PCI ||
                                  (class >> 8) == PCI_CLASS_BRIDGE_CARDBUS))
                        /* Depth first...do children */
                        nextdn = dn->child;
                else if (dn->sibling)
                        /* ok, try next sibling instead. */
                        nextdn = dn->sibling;
                if (!nextdn) {
                        /* Walk up to next valid sibling. */
                        do {
                                dn = dn->parent;
                                if (dn == start)
                                        return NULL;
                        } while (dn->sibling == NULL);
                        nextdn = dn->sibling;
                }
        }
        return NULL;
}
EXPORT_SYMBOL_GPL(pci_traverse_device_nodes);

static struct pci_dn *pci_dn_next_one(struct pci_dn *root,
                                      struct pci_dn *pdn)
{
        struct list_head *next = pdn->child_list.next;

        if (next != &pdn->child_list)
                return list_entry(next, struct pci_dn, list);

        while (1) {
                if (pdn == root)
                        return NULL;

                next = pdn->list.next;
                if (next != &pdn->parent->child_list)
                        break;

                pdn = pdn->parent;
        }

        return list_entry(next, struct pci_dn, list);
}

void *traverse_pci_dn(struct pci_dn *root,
                      void *(*fn)(struct pci_dn *, void *),
                      void *data)
{
        struct pci_dn *pdn = root;
        void *ret;

        /* Only scan the child nodes */
        for (pdn = pci_dn_next_one(root, pdn); pdn;
             pdn = pci_dn_next_one(root, pdn)) {
                ret = fn(pdn, data);
                if (ret)
                        return ret;
        }

        return NULL;
}

static void *add_pdn(struct device_node *dn, void *data)
{
        struct pci_controller *hose = data;
        struct pci_dn *pdn;

        pdn = pci_add_device_node_info(hose, dn);
        if (!pdn)
                return ERR_PTR(-ENOMEM);

        return NULL;
}

/** 
 * pci_devs_phb_init_dynamic - setup pci devices under this PHB
 * phb: pci-to-host bridge (top-level bridge connecting to cpu)
 *
 * This routine is called both during boot, (before the memory
 * subsystem is set up, before kmalloc is valid) and during the 
 * dynamic lpar operation of adding a PHB to a running system.
 */
void pci_devs_phb_init_dynamic(struct pci_controller *phb)
{
        struct device_node *dn = phb->dn;
        struct pci_dn *pdn;

        /* PHB nodes themselves must not match */
        pdn = pci_add_device_node_info(phb, dn);
        if (pdn) {
                pdn->devfn = pdn->busno = -1;
                pdn->vendor_id = pdn->device_id = pdn->class_code = 0;
                pdn->phb = phb;
                phb->pci_data = pdn;
        }

        /* Update dn->phb ptrs for new phb and children devices */
        pci_traverse_device_nodes(dn, add_pdn, phb);
}

/** 
 * pci_devs_phb_init - Initialize phbs and pci devs under them.
 * 
 * This routine walks over all phb's (pci-host bridges) on the
 * system, and sets up assorted pci-related structures 
 * (including pci info in the device node structs) for each
 * pci device found underneath.  This routine runs once,
 * early in the boot sequence.
 */
static int __init pci_devs_phb_init(void)
{
        struct pci_controller *phb, *tmp;

        /* This must be done first so the device nodes have valid pci info! */
        list_for_each_entry_safe(phb, tmp, &hose_list, list_node)
                pci_devs_phb_init_dynamic(phb);

        return 0;
}

core_initcall(pci_devs_phb_init);

static void pci_dev_pdn_setup(struct pci_dev *pdev)
{
        struct pci_dn *pdn;

        if (pdev->dev.archdata.pci_data)
                return;

        /* Setup the fast path */
        pdn = pci_get_pdn(pdev);
        pdev->dev.archdata.pci_data = pdn;
}
DECLARE_PCI_FIXUP_EARLY(PCI_ANY_ID, PCI_ANY_ID, pci_dev_pdn_setup);