/*
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file "COPYING" in the main directory of this archive
 * for more details.
 *
 * Copyright (C) 2005-2006 Silicon Graphics, Inc. All rights reserved.
 *
 * This work was based on the 2.4/2.6 kernel development by Dick Reigner.
 * Work to add BIOS PROM support was completed by Mike Habeck.
 */

#include <linux/acpi.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/pci.h>
#include <linux/pci_hotplug.h>
#include <linux/proc_fs.h>
#include <linux/slab.h>
#include <linux/types.h>
#include <linux/mutex.h>

#include <asm/sn/addrs.h>
#include <asm/sn/geo.h>
#include <asm/sn/l1.h>
#include <asm/sn/module.h>
#include <asm/sn/pcibr_provider.h>
#include <asm/sn/pcibus_provider_defs.h>
#include <asm/sn/pcidev.h>
#include <asm/sn/sn_feature_sets.h>
#include <asm/sn/sn_sal.h>
#include <asm/sn/types.h>
#include <asm/sn/acpi.h>

#include "../pci.h"

MODULE_LICENSE("GPL");
MODULE_AUTHOR("SGI (prarit@sgi.com, dickie@sgi.com, habeck@sgi.com)");
MODULE_DESCRIPTION("SGI Altix Hot Plug PCI Controller Driver");


/* SAL call error codes. Keep in sync with prom header io/include/pcibr.h */
#define PCI_SLOT_ALREADY_UP             2       /* slot already up */
#define PCI_SLOT_ALREADY_DOWN           3       /* slot already down */
#define PCI_L1_ERR                      7       /* L1 console command error */
#define PCI_EMPTY_33MHZ                 15      /* empty 33 MHz bus */


#define PCIIO_ASIC_TYPE_TIOCA           4
#define PCI_L1_QSIZE                    128     /* our L1 message buffer size */
#define SN_MAX_HP_SLOTS                 32      /* max hotplug slots */
#define SN_SLOT_NAME_SIZE               33      /* size of name string */

/* internal list head */
static struct list_head sn_hp_list;

/* hotplug_slot struct's private pointer */
struct slot {
        int device_num;
        struct pci_bus *pci_bus;
        /* this struct for glue internal only */
        struct hotplug_slot *hotplug_slot;
        struct list_head hp_list;
        char physical_path[SN_SLOT_NAME_SIZE];
};

struct pcibr_slot_enable_resp {
        int resp_sub_errno;
        char resp_l1_msg[PCI_L1_QSIZE + 1];
};

struct pcibr_slot_disable_resp {
        int resp_sub_errno;
        char resp_l1_msg[PCI_L1_QSIZE + 1];
};

enum sn_pci_req_e {
        PCI_REQ_SLOT_ELIGIBLE,
        PCI_REQ_SLOT_DISABLE
};

static int enable_slot(struct hotplug_slot *slot);
static int disable_slot(struct hotplug_slot *slot);
static inline int get_power_status(struct hotplug_slot *slot, u8 *value);

static struct hotplug_slot_ops sn_hotplug_slot_ops = {
        .enable_slot            = enable_slot,
        .disable_slot           = disable_slot,
        .get_power_status       = get_power_status,
};

static DEFINE_MUTEX(sn_hotplug_mutex);

static ssize_t path_show(struct pci_slot *pci_slot, char *buf)
{
        int retval = -ENOENT;
        struct slot *slot = pci_slot->hotplug->private;

        if (!slot)
                return retval;

        retval = sprintf(buf, "%s\n", slot->physical_path);
        return retval;
}

static struct pci_slot_attribute sn_slot_path_attr = __ATTR_RO(path);

static int sn_pci_slot_valid(struct pci_bus *pci_bus, int device)
{
        struct pcibus_info *pcibus_info;
        u16 busnum, segment, ioboard_type;

        pcibus_info = SN_PCIBUS_BUSSOFT_INFO(pci_bus);

        /* Check to see if this is a valid slot on 'pci_bus' */
        if (!(pcibus_info->pbi_valid_devices & (1 << device)))
                return -EPERM;

        ioboard_type = sn_ioboard_to_pci_bus(pci_bus);
        busnum = pcibus_info->pbi_buscommon.bs_persist_busnum;
        segment = pci_domain_nr(pci_bus) & 0xf;

        /* Do not allow hotplug operations on base I/O cards */
        if ((ioboard_type == L1_BRICKTYPE_IX ||
             ioboard_type == L1_BRICKTYPE_IA) &&
            (segment == 1 && busnum == 0 && device != 1))
                return -EPERM;

        return 1;
}

static int sn_pci_bus_valid(struct pci_bus *pci_bus)
{
        struct pcibus_info *pcibus_info;
        u32 asic_type;
        u16 ioboard_type;

        /* Don't register slots hanging off the TIOCA bus */
        pcibus_info = SN_PCIBUS_BUSSOFT_INFO(pci_bus);
        asic_type = pcibus_info->pbi_buscommon.bs_asic_type;
        if (asic_type == PCIIO_ASIC_TYPE_TIOCA)
                return -EPERM;

        /* Only register slots in I/O Bricks that support hotplug */
        ioboard_type = sn_ioboard_to_pci_bus(pci_bus);
        switch (ioboard_type) {
                case L1_BRICKTYPE_IX:
                case L1_BRICKTYPE_PX:
                case L1_BRICKTYPE_IA:
                case L1_BRICKTYPE_PA:
                case L1_BOARDTYPE_PCIX3SLOT:
                        return 1;
                        break;
                default:
                        return -EPERM;
                        break;
        }

        return -EIO;
}

static int sn_hp_slot_private_alloc(struct hotplug_slot *bss_hotplug_slot,
                                    struct pci_bus *pci_bus, int device,
                                    char *name)
{
        struct pcibus_info *pcibus_info;
        struct slot *slot;

        pcibus_info = SN_PCIBUS_BUSSOFT_INFO(pci_bus);

        slot = kzalloc(sizeof(*slot), GFP_KERNEL);
        if (!slot)
                return -ENOMEM;
        bss_hotplug_slot->private = slot;

        slot->device_num = device;
        slot->pci_bus = pci_bus;
        sprintf(name, "%04x:%02x:%02x",
                pci_domain_nr(pci_bus),
                ((u16)pcibus_info->pbi_buscommon.bs_persist_busnum),
                device + 1);

        sn_generate_path(pci_bus, slot->physical_path);

        slot->hotplug_slot = bss_hotplug_slot;
        list_add(&slot->hp_list, &sn_hp_list);

        return 0;
}

static struct hotplug_slot *sn_hp_destroy(void)
{
        struct slot *slot;
        struct pci_slot *pci_slot;
        struct hotplug_slot *bss_hotplug_slot = NULL;

        list_for_each_entry(slot, &sn_hp_list, hp_list) {
                bss_hotplug_slot = slot->hotplug_slot;
                pci_slot = bss_hotplug_slot->pci_slot;
                list_del(&((struct slot *)bss_hotplug_slot->private)->
                         hp_list);
                sysfs_remove_file(&pci_slot->kobj,
                                  &sn_slot_path_attr.attr);
                break;
        }
        return bss_hotplug_slot;
}

static void sn_bus_free_data(struct pci_dev *dev)
{
        struct pci_bus *subordinate_bus;
        struct pci_dev *child;

        /* Recursively clean up sn_irq_info structs */
        if (dev->subordinate) {
                subordinate_bus = dev->subordinate;
                list_for_each_entry(child, &subordinate_bus->devices, bus_list)
                        sn_bus_free_data(child);
        }
        /*
         * Some drivers may use dma accesses during the
         * driver remove function. We release the sysdata
         * areas after the driver remove functions have
         * been called.
         */
        sn_bus_store_sysdata(dev);
        sn_pci_unfixup_slot(dev);
}

static int sn_slot_enable(struct hotplug_slot *bss_hotplug_slot,
                          int device_num, char **ssdt)
{
        struct slot *slot = bss_hotplug_slot->private;
        struct pcibus_info *pcibus_info;
        struct pcibr_slot_enable_resp resp;
        int rc;

        pcibus_info = SN_PCIBUS_BUSSOFT_INFO(slot->pci_bus);

        /*
         * Power-on and initialize the slot in the SN
         * PCI infrastructure.
         */
        rc = sal_pcibr_slot_enable(pcibus_info, device_num, &resp, ssdt);


        if (rc == PCI_SLOT_ALREADY_UP) {
                dev_dbg(&slot->pci_bus->self->dev, "is already active\n");
                return 1; /* return 1 to user */
        }

        if (rc == PCI_L1_ERR) {
                dev_dbg(&slot->pci_bus->self->dev, "L1 failure %d with message: %s",
                        resp.resp_sub_errno, resp.resp_l1_msg);
                return -EPERM;
        }

        if (rc) {
                dev_dbg(&slot->pci_bus->self->dev, "insert failed with error %d sub-error %d\n",
                        rc, resp.resp_sub_errno);
                return -EIO;
        }

        pcibus_info = SN_PCIBUS_BUSSOFT_INFO(slot->pci_bus);
        pcibus_info->pbi_enabled_devices |= (1 << device_num);

        return 0;
}

static int sn_slot_disable(struct hotplug_slot *bss_hotplug_slot,
                           int device_num, int action)
{
        struct slot *slot = bss_hotplug_slot->private;
        struct pcibus_info *pcibus_info;
        struct pcibr_slot_disable_resp resp;
        int rc;

        pcibus_info = SN_PCIBUS_BUSSOFT_INFO(slot->pci_bus);

        rc = sal_pcibr_slot_disable(pcibus_info, device_num, action, &resp);

        if ((action == PCI_REQ_SLOT_ELIGIBLE) &&
            (rc == PCI_SLOT_ALREADY_DOWN)) {
                dev_dbg(&slot->pci_bus->self->dev, "Slot %s already inactive\n", slot->physical_path);
                return 1; /* return 1 to user */
        }

        if ((action == PCI_REQ_SLOT_ELIGIBLE) && (rc == PCI_EMPTY_33MHZ)) {
                dev_dbg(&slot->pci_bus->self->dev, "Cannot remove last 33MHz card\n");
                return -EPERM;
        }

        if ((action == PCI_REQ_SLOT_ELIGIBLE) && (rc == PCI_L1_ERR)) {
                dev_dbg(&slot->pci_bus->self->dev, "L1 failure %d with message \n%s\n",
                        resp.resp_sub_errno, resp.resp_l1_msg);
                return -EPERM;
        }

        if ((action == PCI_REQ_SLOT_ELIGIBLE) && rc) {
                dev_dbg(&slot->pci_bus->self->dev, "remove failed with error %d sub-error %d\n",
                        rc, resp.resp_sub_errno);
                return -EIO;
        }

        if ((action == PCI_REQ_SLOT_ELIGIBLE) && !rc)
                return 0;

        if ((action == PCI_REQ_SLOT_DISABLE) && !rc) {
                pcibus_info = SN_PCIBUS_BUSSOFT_INFO(slot->pci_bus);
                pcibus_info->pbi_enabled_devices &= ~(1 << device_num);
                dev_dbg(&slot->pci_bus->self->dev, "remove successful\n");
                return 0;
        }

        if ((action == PCI_REQ_SLOT_DISABLE) && rc) {
                dev_dbg(&slot->pci_bus->self->dev, "remove failed rc = %d\n", rc);
        }

        return rc;
}

/*
 * Power up and configure the slot via a SAL call to PROM.
 * Scan slot (and any children), do any platform specific fixup,
 * and find device driver.
 */
static int enable_slot(struct hotplug_slot *bss_hotplug_slot)
{
        struct slot *slot = bss_hotplug_slot->private;
        struct pci_bus *new_bus = NULL;
        struct pci_dev *dev;
        int num_funcs;
        int new_ppb = 0;
        int rc;
        char *ssdt = NULL;
        void pcibios_fixup_device_resources(struct pci_dev *);

        /* Serialize the Linux PCI infrastructure */
        mutex_lock(&sn_hotplug_mutex);

        /*
         * Power-on and initialize the slot in the SN
         * PCI infrastructure. Also, retrieve the ACPI SSDT
         * table for the slot (if ACPI capable PROM).
         */
        rc = sn_slot_enable(bss_hotplug_slot, slot->device_num, &ssdt);
        if (rc) {
                mutex_unlock(&sn_hotplug_mutex);
                return rc;
        }

        if (ssdt)
                ssdt = __va(ssdt);
        /* Add the new SSDT for the slot to the ACPI namespace */
        if (SN_ACPI_BASE_SUPPORT() && ssdt) {
                acpi_status ret;

                ret = acpi_load_table((struct acpi_table_header *)ssdt);
                if (ACPI_FAILURE(ret)) {
                        printk(KERN_ERR "%s: acpi_load_table failed (0x%x)\n",
                               __func__, ret);
                        /* try to continue on */
                }
        }

        num_funcs = pci_scan_slot(slot->pci_bus,
                                  PCI_DEVFN(slot->device_num + 1, 0));
        if (!num_funcs) {
                dev_dbg(&slot->pci_bus->self->dev, "no device in slot\n");
                mutex_unlock(&sn_hotplug_mutex);
                return -ENODEV;
        }

        /*
         * Map SN resources for all functions on the card
         * to the Linux PCI interface and tell the drivers
         * about them.
         */
        list_for_each_entry(dev, &slot->pci_bus->devices, bus_list) {
                if (PCI_SLOT(dev->devfn) != slot->device_num + 1)
                        continue;

                /* Need to do slot fixup on PPB before fixup of children
                 * (PPB's pcidev_info needs to be in pcidev_info list
                 * before child's SN_PCIDEV_INFO() call to setup
                 * pdi_host_pcidev_info).
                 */
                pcibios_fixup_device_resources(dev);
                if (SN_ACPI_BASE_SUPPORT())
                        sn_acpi_slot_fixup(dev);
                else
                        sn_io_slot_fixup(dev);
                if (dev->hdr_type == PCI_HEADER_TYPE_BRIDGE) {
                        pci_hp_add_bridge(dev);
                        if (dev->subordinate) {
                                new_bus = dev->subordinate;
                                new_ppb = 1;
                        }
                }
        }

        /*
         * Add the slot's devices to the ACPI infrastructure */
        if (SN_ACPI_BASE_SUPPORT() && ssdt) {
                unsigned long long adr;
                struct acpi_device *pdevice;
                acpi_handle phandle;
                acpi_handle chandle = NULL;
                acpi_handle rethandle;
                acpi_status ret;

                phandle = acpi_device_handle(PCI_CONTROLLER(slot->pci_bus)->companion);

                if (acpi_bus_get_device(phandle, &pdevice)) {
                        dev_dbg(&slot->pci_bus->self->dev, "no parent device, assuming NULL\n");
                        pdevice = NULL;
                }

                acpi_scan_lock_acquire();
                /*
                 * Walk the rootbus node's immediate children looking for
                 * the slot's device node(s). There can be more than
                 * one for multifunction devices.
                 */
                for (;;) {
                        rethandle = NULL;
                        ret = acpi_get_next_object(ACPI_TYPE_DEVICE,
                                                   phandle, chandle,
                                                   &rethandle);

                        if (ret == AE_NOT_FOUND || rethandle == NULL)
                                break;

                        chandle = rethandle;

                        ret = acpi_evaluate_integer(chandle, METHOD_NAME__ADR,
                                                    NULL, &adr);

                        if (ACPI_SUCCESS(ret) &&
                            (adr>>16) == (slot->device_num + 1)) {

                                ret = acpi_bus_scan(chandle);
                                if (ACPI_FAILURE(ret)) {
                                        printk(KERN_ERR "%s: acpi_bus_scan failed (0x%x) for slot %d func %d\n",
                                               __func__, ret, (int)(adr>>16),
                                               (int)(adr&0xffff));
                                        /* try to continue on */
                                }
                        }
                }
                acpi_scan_lock_release();
        }

        pci_lock_rescan_remove();

        /* Call the driver for the new device */
        pci_bus_add_devices(slot->pci_bus);
        /* Call the drivers for the new devices subordinate to PPB */
        if (new_ppb)
                pci_bus_add_devices(new_bus);

        pci_unlock_rescan_remove();
        mutex_unlock(&sn_hotplug_mutex);

        if (rc == 0)
                dev_dbg(&slot->pci_bus->self->dev, "insert operation successful\n");
        else
                dev_dbg(&slot->pci_bus->self->dev, "insert operation failed rc = %d\n", rc);

        return rc;
}

static int disable_slot(struct hotplug_slot *bss_hotplug_slot)
{
        struct slot *slot = bss_hotplug_slot->private;
        struct pci_dev *dev, *temp;
        int rc;
        acpi_owner_id ssdt_id = 0;

        /* Acquire update access to the bus */
        mutex_lock(&sn_hotplug_mutex);

        /* is it okay to bring this slot down? */
        rc = sn_slot_disable(bss_hotplug_slot, slot->device_num,
                             PCI_REQ_SLOT_ELIGIBLE);
        if (rc)
                goto leaving;

        /* free the ACPI resources for the slot */
        if (SN_ACPI_BASE_SUPPORT() &&
                PCI_CONTROLLER(slot->pci_bus)->companion) {
                unsigned long long adr;
                struct acpi_device *device;
                acpi_handle phandle;
                acpi_handle chandle = NULL;
                acpi_handle rethandle;
                acpi_status ret;

                /* Get the rootbus node pointer */
                phandle = acpi_device_handle(PCI_CONTROLLER(slot->pci_bus)->companion);

                acpi_scan_lock_acquire();
                /*
                 * Walk the rootbus node's immediate children looking for
                 * the slot's device node(s). There can be more than
                 * one for multifunction devices.
                 */
                for (;;) {
                        rethandle = NULL;
                        ret = acpi_get_next_object(ACPI_TYPE_DEVICE,
                                                   phandle, chandle,
                                                   &rethandle);

                        if (ret == AE_NOT_FOUND || rethandle == NULL)
                                break;

                        chandle = rethandle;

                        ret = acpi_evaluate_integer(chandle,
                                                    METHOD_NAME__ADR,
                                                    NULL, &adr);
                        if (ACPI_SUCCESS(ret) &&
                            (adr>>16) == (slot->device_num + 1)) {
                                /* retain the owner id */
                                acpi_get_id(chandle, &ssdt_id);

                                ret = acpi_bus_get_device(chandle,
                                                          &device);
                                if (ACPI_SUCCESS(ret))
                                        acpi_bus_trim(device);
                        }
                }
                acpi_scan_lock_release();
        }

        pci_lock_rescan_remove();
        /* Free the SN resources assigned to the Linux device.*/
        list_for_each_entry_safe(dev, temp, &slot->pci_bus->devices, bus_list) {
                if (PCI_SLOT(dev->devfn) != slot->device_num + 1)
                        continue;

                pci_dev_get(dev);
                sn_bus_free_data(dev);
                pci_stop_and_remove_bus_device(dev);
                pci_dev_put(dev);
        }
        pci_unlock_rescan_remove();

        /* Remove the SSDT for the slot from the ACPI namespace */
        if (SN_ACPI_BASE_SUPPORT() && ssdt_id) {
                acpi_status ret;
                ret = acpi_unload_table_id(ssdt_id);
                if (ACPI_FAILURE(ret)) {
                        printk(KERN_ERR "%s: acpi_unload_table_id failed (0x%x) for id %d\n",
                               __func__, ret, ssdt_id);
                        /* try to continue on */
                }
        }

        /* free the collected sysdata pointers */
        sn_bus_free_sysdata();

        /* Deactivate slot */
        rc = sn_slot_disable(bss_hotplug_slot, slot->device_num,
                             PCI_REQ_SLOT_DISABLE);
 leaving:
        /* Release the bus lock */
        mutex_unlock(&sn_hotplug_mutex);

        return rc;
}

static inline int get_power_status(struct hotplug_slot *bss_hotplug_slot,
                                   u8 *value)
{
        struct slot *slot = bss_hotplug_slot->private;
        struct pcibus_info *pcibus_info;
        u32 power;

        pcibus_info = SN_PCIBUS_BUSSOFT_INFO(slot->pci_bus);
        mutex_lock(&sn_hotplug_mutex);
        power = pcibus_info->pbi_enabled_devices & (1 << slot->device_num);
        *value = power ? 1 : 0;
        mutex_unlock(&sn_hotplug_mutex);
        return 0;
}

static void sn_release_slot(struct hotplug_slot *bss_hotplug_slot)
{
        kfree(bss_hotplug_slot->info);
        kfree(bss_hotplug_slot->private);
        kfree(bss_hotplug_slot);
}

static int sn_hotplug_slot_register(struct pci_bus *pci_bus)
{
        int device;
        struct pci_slot *pci_slot;
        struct hotplug_slot *bss_hotplug_slot;
        char name[SN_SLOT_NAME_SIZE];
        int rc = 0;

        /*
         * Currently only four devices are supported,
         * in the future there maybe more -- up to 32.
         */

        for (device = 0; device < SN_MAX_HP_SLOTS ; device++) {
                if (sn_pci_slot_valid(pci_bus, device) != 1)
                        continue;

                bss_hotplug_slot = kzalloc(sizeof(*bss_hotplug_slot),
                                           GFP_KERNEL);
                if (!bss_hotplug_slot) {
                        rc = -ENOMEM;
                        goto alloc_err;
                }

                bss_hotplug_slot->info =
                        kzalloc(sizeof(struct hotplug_slot_info),
                                GFP_KERNEL);
                if (!bss_hotplug_slot->info) {
                        rc = -ENOMEM;
                        goto alloc_err;
                }

                if (sn_hp_slot_private_alloc(bss_hotplug_slot,
                                             pci_bus, device, name)) {
                        rc = -ENOMEM;
                        goto alloc_err;
                }
                bss_hotplug_slot->ops = &sn_hotplug_slot_ops;
                bss_hotplug_slot->release = &sn_release_slot;

                rc = pci_hp_register(bss_hotplug_slot, pci_bus, device, name);
                if (rc)
                        goto register_err;

                pci_slot = bss_hotplug_slot->pci_slot;
                rc = sysfs_create_file(&pci_slot->kobj,
                                       &sn_slot_path_attr.attr);
                if (rc)
                        goto register_err;
        }
        dev_dbg(&pci_bus->self->dev, "Registered bus with hotplug\n");
        return rc;

register_err:
        dev_dbg(&pci_bus->self->dev, "bus failed to register with err = %d\n",
                rc);

alloc_err:
        if (rc == -ENOMEM)
                dev_dbg(&pci_bus->self->dev, "Memory allocation error\n");

        /* destroy THIS element */
        if (bss_hotplug_slot)
                sn_release_slot(bss_hotplug_slot);

        /* destroy anything else on the list */
        while ((bss_hotplug_slot = sn_hp_destroy()))
                pci_hp_deregister(bss_hotplug_slot);

        return rc;
}

static int __init sn_pci_hotplug_init(void)
{
        struct pci_bus *pci_bus = NULL;
        int rc;
        int registered = 0;

        if (!sn_prom_feature_available(PRF_HOTPLUG_SUPPORT)) {
                printk(KERN_ERR "%s: PROM version does not support hotplug.\n",
                       __func__);
                return -EPERM;
        }

        INIT_LIST_HEAD(&sn_hp_list);

        while ((pci_bus = pci_find_next_bus(pci_bus))) {
                if (!pci_bus->sysdata)
                        continue;

                rc = sn_pci_bus_valid(pci_bus);
                if (rc != 1) {
                        dev_dbg(&pci_bus->self->dev, "not a valid hotplug bus\n");
                        continue;
                }
                dev_dbg(&pci_bus->self->dev, "valid hotplug bus\n");

                rc = sn_hotplug_slot_register(pci_bus);
                if (!rc) {
                        registered = 1;
                } else {
                        registered = 0;
                        break;
                }
        }

        return registered == 1 ? 0 : -ENODEV;
}

static void __exit sn_pci_hotplug_exit(void)
{
        struct hotplug_slot *bss_hotplug_slot;

        while ((bss_hotplug_slot = sn_hp_destroy()))
                pci_hp_deregister(bss_hotplug_slot);

        if (!list_empty(&sn_hp_list))
                printk(KERN_ERR "%s: internal list is not empty\n", __FILE__);
}

module_init(sn_pci_hotplug_init);
module_exit(sn_pci_hotplug_exit);