// SPDX-License-Identifier: GPL-2.0+
/*
 * Interface for Dynamic Logical Partitioning of I/O Slots on
 * RPA-compliant PPC64 platform.
 *
 * John Rose <johnrose@austin.ibm.com>
 * Linda Xie <lxie@us.ibm.com>
 *
 * October 2003
 *
 * Copyright (C) 2003 IBM.
 */

#undef DEBUG

#include <linux/init.h>
#include <linux/module.h>
#include <linux/pci.h>
#include <linux/string.h>
#include <linux/vmalloc.h>

#include <asm/pci-bridge.h>
#include <linux/mutex.h>
#include <asm/rtas.h>
#include <asm/vio.h>
#include <linux/firmware.h>

#include "../pci.h"
#include "rpaphp.h"
#include "rpadlpar.h"

static DEFINE_MUTEX(rpadlpar_mutex);

#define DLPAR_MODULE_NAME "rpadlpar_io"

#define NODE_TYPE_VIO  1
#define NODE_TYPE_SLOT 2
#define NODE_TYPE_PHB  3

static struct device_node *find_vio_slot_node(char *drc_name)
{
        struct device_node *parent = of_find_node_by_name(NULL, "vdevice");
        struct device_node *dn;
        int rc;

        if (!parent)
                return NULL;

        for_each_child_of_node(parent, dn) {
                rc = rpaphp_check_drc_props(dn, drc_name, NULL);
                if (rc == 0)
                        break;
        }
        of_node_put(parent);

        return dn;
}

/* Find dlpar-capable pci node that contains the specified name and type */
static struct device_node *find_php_slot_pci_node(char *drc_name,
                                                  char *drc_type)
{
        struct device_node *np;
        int rc;

        for_each_node_by_name(np, "pci") {
                rc = rpaphp_check_drc_props(np, drc_name, drc_type);
                if (rc == 0)
                        break;
        }

        return np;
}

/* Returns a device_node with its reference count incremented */
static struct device_node *find_dlpar_node(char *drc_name, int *node_type)
{
        struct device_node *dn;

        dn = find_php_slot_pci_node(drc_name, "SLOT");
        if (dn) {
                *node_type = NODE_TYPE_SLOT;
                return dn;
        }

        dn = find_php_slot_pci_node(drc_name, "PHB");
        if (dn) {
                *node_type = NODE_TYPE_PHB;
                return dn;
        }

        dn = find_vio_slot_node(drc_name);
        if (dn) {
                *node_type = NODE_TYPE_VIO;
                return dn;
        }

        return NULL;
}

/**
 * find_php_slot - return hotplug slot structure for device node
 * @dn: target &device_node
 *
 * This routine will return the hotplug slot structure
 * for a given device node. Note that built-in PCI slots
 * may be dlpar-able, but not hot-pluggable, so this routine
 * will return NULL for built-in PCI slots.
 */
static struct slot *find_php_slot(struct device_node *dn)
{
        struct slot *slot, *next;

        list_for_each_entry_safe(slot, next, &rpaphp_slot_head,
                                 rpaphp_slot_list) {
                if (slot->dn == dn)
                        return slot;
        }

        return NULL;
}

static struct pci_dev *dlpar_find_new_dev(struct pci_bus *parent,
                                        struct device_node *dev_dn)
{
        struct pci_dev *tmp = NULL;
        struct device_node *child_dn;

        list_for_each_entry(tmp, &parent->devices, bus_list) {
                child_dn = pci_device_to_OF_node(tmp);
                if (child_dn == dev_dn)
                        return tmp;
        }
        return NULL;
}

static void dlpar_pci_add_bus(struct device_node *dn)
{
        struct pci_dn *pdn = PCI_DN(dn);
        struct pci_controller *phb = pdn->phb;
        struct pci_dev *dev = NULL;

        pseries_eeh_init_edev_recursive(pdn);

        /* Add EADS device to PHB bus, adding new entry to bus->devices */
        dev = of_create_pci_dev(dn, phb->bus, pdn->devfn);
        if (!dev) {
                printk(KERN_ERR "%s: failed to create pci dev for %pOF\n",
                                __func__, dn);
                return;
        }

        /* Scan below the new bridge */
        if (pci_is_bridge(dev))
                of_scan_pci_bridge(dev);

        /* Map IO space for child bus, which may or may not succeed */
        pcibios_map_io_space(dev->subordinate);

        /* Finish adding it : resource allocation, adding devices, etc...
         * Note that we need to perform the finish pass on the -parent-
         * bus of the EADS bridge so the bridge device itself gets
         * properly added
         */
        pcibios_finish_adding_to_bus(phb->bus);
}

static int dlpar_add_pci_slot(char *drc_name, struct device_node *dn)
{
        struct pci_dev *dev;
        struct pci_controller *phb;

        if (pci_find_bus_by_node(dn))
                return -EINVAL;

        /* Add pci bus */
        dlpar_pci_add_bus(dn);

        /* Confirm new bridge dev was created */
        phb = PCI_DN(dn)->phb;
        dev = dlpar_find_new_dev(phb->bus, dn);

        if (!dev) {
                printk(KERN_ERR "%s: unable to add bus %s\n", __func__,
                        drc_name);
                return -EIO;
        }

        if (dev->hdr_type != PCI_HEADER_TYPE_BRIDGE) {
                printk(KERN_ERR "%s: unexpected header type %d, unable to add bus %s\n",
                        __func__, dev->hdr_type, drc_name);
                return -EIO;
        }

        /* Add hotplug slot */
        if (rpaphp_add_slot(dn)) {
                printk(KERN_ERR "%s: unable to add hotplug slot %s\n",
                        __func__, drc_name);
                return -EIO;
        }
        return 0;
}

static int dlpar_remove_phb(char *drc_name, struct device_node *dn)
{
        struct slot *slot;
        struct pci_dn *pdn;
        int rc = 0;

        if (!pci_find_bus_by_node(dn))
                return -EINVAL;

        /* If pci slot is hotpluggable, use hotplug to remove it */
        slot = find_php_slot(dn);
        if (slot && rpaphp_deregister_slot(slot)) {
                printk(KERN_ERR "%s: unable to remove hotplug slot %s\n",
                       __func__, drc_name);
                return -EIO;
        }

        pdn = dn->data;
        BUG_ON(!pdn || !pdn->phb);
        rc = remove_phb_dynamic(pdn->phb);
        if (rc < 0)
                return rc;

        pdn->phb = NULL;

        return 0;
}

static int dlpar_add_phb(char *drc_name, struct device_node *dn)
{
        struct pci_controller *phb;

        if (PCI_DN(dn) && PCI_DN(dn)->phb) {
                /* PHB already exists */
                return -EINVAL;
        }

        phb = init_phb_dynamic(dn);
        if (!phb)
                return -EIO;

        if (rpaphp_add_slot(dn)) {
                printk(KERN_ERR "%s: unable to add hotplug slot %s\n",
                        __func__, drc_name);
                return -EIO;
        }
        return 0;
}

static int dlpar_add_vio_slot(char *drc_name, struct device_node *dn)
{
        struct vio_dev *vio_dev;

        vio_dev = vio_find_node(dn);
        if (vio_dev) {
                put_device(&vio_dev->dev);
                return -EINVAL;
        }

        if (!vio_register_device_node(dn)) {
                printk(KERN_ERR
                        "%s: failed to register vio node %s\n",
                        __func__, drc_name);
                return -EIO;
        }
        return 0;
}

/**
 * dlpar_add_slot - DLPAR add an I/O Slot
 * @drc_name: drc-name of newly added slot
 *
 * Make the hotplug module and the kernel aware of a newly added I/O Slot.
 * Return Codes:
 * 0                    Success
 * -ENODEV              Not a valid drc_name
 * -EINVAL              Slot already added
 * -ERESTARTSYS         Signalled before obtaining lock
 * -EIO                 Internal PCI Error
 */
int dlpar_add_slot(char *drc_name)
{
        struct device_node *dn = NULL;
        int node_type;
        int rc = -EIO;

        if (mutex_lock_interruptible(&rpadlpar_mutex))
                return -ERESTARTSYS;

        /* Find newly added node */
        dn = find_dlpar_node(drc_name, &node_type);
        if (!dn) {
                rc = -ENODEV;
                goto exit;
        }

        switch (node_type) {
                case NODE_TYPE_VIO:
                        rc = dlpar_add_vio_slot(drc_name, dn);
                        break;
                case NODE_TYPE_SLOT:
                        rc = dlpar_add_pci_slot(drc_name, dn);
                        break;
                case NODE_TYPE_PHB:
                        rc = dlpar_add_phb(drc_name, dn);
                        break;
        }
        of_node_put(dn);

        printk(KERN_INFO "%s: slot %s added\n", DLPAR_MODULE_NAME, drc_name);
exit:
        mutex_unlock(&rpadlpar_mutex);
        return rc;
}

/**
 * dlpar_remove_vio_slot - DLPAR remove a virtual I/O Slot
 * @drc_name: drc-name of newly added slot
 * @dn: &device_node
 *
 * Remove the kernel and hotplug representations of an I/O Slot.
 * Return Codes:
 * 0                    Success
 * -EINVAL              Vio dev doesn't exist
 */
static int dlpar_remove_vio_slot(char *drc_name, struct device_node *dn)
{
        struct vio_dev *vio_dev;

        vio_dev = vio_find_node(dn);
        if (!vio_dev)
                return -EINVAL;

        vio_unregister_device(vio_dev);

        put_device(&vio_dev->dev);

        return 0;
}

/**
 * dlpar_remove_pci_slot - DLPAR remove a PCI I/O Slot
 * @drc_name: drc-name of newly added slot
 * @dn: &device_node
 *
 * Remove the kernel and hotplug representations of a PCI I/O Slot.
 * Return Codes:
 * 0                    Success
 * -ENODEV              Not a valid drc_name
 * -EIO                 Internal PCI Error
 */
static int dlpar_remove_pci_slot(char *drc_name, struct device_node *dn)
{
        struct pci_bus *bus;
        struct slot *slot;
        int ret = 0;

        pci_lock_rescan_remove();

        bus = pci_find_bus_by_node(dn);
        if (!bus) {
                ret = -EINVAL;
                goto out;
        }

        pr_debug("PCI: Removing PCI slot below EADS bridge %s\n",
                 bus->self ? pci_name(bus->self) : "<!PHB!>");

        slot = find_php_slot(dn);
        if (slot) {
                pr_debug("PCI: Removing hotplug slot for %04x:%02x...\n",
                         pci_domain_nr(bus), bus->number);

                if (rpaphp_deregister_slot(slot)) {
                        printk(KERN_ERR
                                "%s: unable to remove hotplug slot %s\n",
                                __func__, drc_name);
                        ret = -EIO;
                        goto out;
                }
        }

        /* Remove all devices below slot */
        pci_hp_remove_devices(bus);

        /* Unmap PCI IO space */
        if (pcibios_unmap_io_space(bus)) {
                printk(KERN_ERR "%s: failed to unmap bus range\n",
                        __func__);
                ret = -ERANGE;
                goto out;
        }

        /* Remove the EADS bridge device itself */
        BUG_ON(!bus->self);
        pr_debug("PCI: Now removing bridge device %s\n", pci_name(bus->self));
        pci_stop_and_remove_bus_device(bus->self);

 out:
        pci_unlock_rescan_remove();
        return ret;
}

/**
 * dlpar_remove_slot - DLPAR remove an I/O Slot
 * @drc_name: drc-name of newly added slot
 *
 * Remove the kernel and hotplug representations of an I/O Slot.
 * Return Codes:
 * 0                    Success
 * -ENODEV              Not a valid drc_name
 * -EINVAL              Slot already removed
 * -ERESTARTSYS         Signalled before obtaining lock
 * -EIO                 Internal Error
 */
int dlpar_remove_slot(char *drc_name)
{
        struct device_node *dn;
        int node_type;
        int rc = 0;

        if (mutex_lock_interruptible(&rpadlpar_mutex))
                return -ERESTARTSYS;

        dn = find_dlpar_node(drc_name, &node_type);
        if (!dn) {
                rc = -ENODEV;
                goto exit;
        }

        switch (node_type) {
                case NODE_TYPE_VIO:
                        rc = dlpar_remove_vio_slot(drc_name, dn);
                        break;
                case NODE_TYPE_PHB:
                        rc = dlpar_remove_phb(drc_name, dn);
                        break;
                case NODE_TYPE_SLOT:
                        rc = dlpar_remove_pci_slot(drc_name, dn);
                        break;
        }
        of_node_put(dn);
        vm_unmap_aliases();

        printk(KERN_INFO "%s: slot %s removed\n", DLPAR_MODULE_NAME, drc_name);
exit:
        mutex_unlock(&rpadlpar_mutex);
        return rc;
}

static inline int is_dlpar_capable(void)
{
        int rc = rtas_token("ibm,configure-connector");

        return (int) (rc != RTAS_UNKNOWN_SERVICE);
}

static int __init rpadlpar_io_init(void)
{

        if (!is_dlpar_capable()) {
                printk(KERN_WARNING "%s: partition not DLPAR capable\n",
                        __func__);
                return -EPERM;
        }

        return dlpar_sysfs_init();
}

static void __exit rpadlpar_io_exit(void)
{
        dlpar_sysfs_exit();
}

module_init(rpadlpar_io_init);
module_exit(rpadlpar_io_exit);
MODULE_LICENSE("GPL");