// SPDX-License-Identifier: GPL-2.0+
/*
 * PCI Express Hot Plug Controller Driver
 *
 * Copyright (C) 1995,2001 Compaq Computer Corporation
 * Copyright (C) 2001 Greg Kroah-Hartman (greg@kroah.com)
 * Copyright (C) 2001 IBM Corp.
 * Copyright (C) 2003-2004 Intel Corporation
 *
 * All rights reserved.
 *
 * Send feedback to <greg@kroah.com>, <kristen.c.accardi@intel.com>
 *
 */

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/slab.h>
#include <linux/pci.h>
#include "../pci.h"
#include "pciehp.h"

static void interrupt_event_handler(struct work_struct *work);

void pciehp_queue_interrupt_event(struct slot *p_slot, u32 event_type)
{
        struct event_info *info;

        info = kmalloc(sizeof(*info), GFP_ATOMIC);
        if (!info) {
                ctrl_err(p_slot->ctrl, "dropped event %d (ENOMEM)\n", event_type);
                return;
        }

        INIT_WORK(&info->work, interrupt_event_handler);
        info->event_type = event_type;
        info->p_slot = p_slot;
        queue_work(p_slot->wq, &info->work);
}

/* The following routines constitute the bulk of the
   hotplug controller logic
 */

static void set_slot_off(struct controller *ctrl, struct slot *pslot)
{
        /* turn off slot, turn on Amber LED, turn off Green LED if supported*/
        if (POWER_CTRL(ctrl)) {
                pciehp_power_off_slot(pslot);

                /*
                 * After turning power off, we must wait for at least 1 second
                 * before taking any action that relies on power having been
                 * removed from the slot/adapter.
                 */
                msleep(1000);
        }

        pciehp_green_led_off(pslot);
        pciehp_set_attention_status(pslot, 1);
}

/**
 * board_added - Called after a board has been added to the system.
 * @p_slot: &slot where board is added
 *
 * Turns power on for the board.
 * Configures board.
 */
static int board_added(struct slot *p_slot)
{
        int retval = 0;
        struct controller *ctrl = p_slot->ctrl;
        struct pci_bus *parent = ctrl->pcie->port->subordinate;

        if (POWER_CTRL(ctrl)) {
                /* Power on slot */
                retval = pciehp_power_on_slot(p_slot);
                if (retval)
                        return retval;
        }

        pciehp_green_led_blink(p_slot);

        /* Check link training status */
        retval = pciehp_check_link_status(ctrl);
        if (retval) {
                ctrl_err(ctrl, "Failed to check link status\n");
                goto err_exit;
        }

        /* Check for a power fault */
        if (ctrl->power_fault_detected || pciehp_query_power_fault(p_slot)) {
                ctrl_err(ctrl, "Slot(%s): Power fault\n", slot_name(p_slot));
                retval = -EIO;
                goto err_exit;
        }

        retval = pciehp_configure_device(p_slot);
        if (retval) {
                if (retval != -EEXIST) {
                        ctrl_err(ctrl, "Cannot add device at %04x:%02x:00\n",
                                 pci_domain_nr(parent), parent->number);
                        goto err_exit;
                }
        }

        pciehp_green_led_on(p_slot);
        pciehp_set_attention_status(p_slot, 0);
        return 0;

err_exit:
        set_slot_off(ctrl, p_slot);
        return retval;
}

/**
 * remove_board - Turns off slot and LEDs
 * @p_slot: slot where board is being removed
 */
static int remove_board(struct slot *p_slot)
{
        int retval;
        struct controller *ctrl = p_slot->ctrl;

        retval = pciehp_unconfigure_device(p_slot);
        if (retval)
                return retval;

        if (POWER_CTRL(ctrl)) {
                pciehp_power_off_slot(p_slot);

                /*
                 * After turning power off, we must wait for at least 1 second
                 * before taking any action that relies on power having been
                 * removed from the slot/adapter.
                 */
                msleep(1000);
        }

        /* turn off Green LED */
        pciehp_green_led_off(p_slot);
        return 0;
}

struct power_work_info {
        struct slot *p_slot;
        struct work_struct work;
        unsigned int req;
#define DISABLE_REQ 0
#define ENABLE_REQ  1
};

/**
 * pciehp_power_thread - handle pushbutton events
 * @work: &struct work_struct describing work to be done
 *
 * Scheduled procedure to handle blocking stuff for the pushbuttons.
 * Handles all pending events and exits.
 */
static void pciehp_power_thread(struct work_struct *work)
{
        struct power_work_info *info =
                container_of(work, struct power_work_info, work);
        struct slot *p_slot = info->p_slot;
        int ret;

        switch (info->req) {
        case DISABLE_REQ:
                mutex_lock(&p_slot->hotplug_lock);
                pciehp_disable_slot(p_slot);
                mutex_unlock(&p_slot->hotplug_lock);
                mutex_lock(&p_slot->lock);
                p_slot->state = STATIC_STATE;
                mutex_unlock(&p_slot->lock);
                break;
        case ENABLE_REQ:
                mutex_lock(&p_slot->hotplug_lock);
                ret = pciehp_enable_slot(p_slot);
                mutex_unlock(&p_slot->hotplug_lock);
                if (ret)
                        pciehp_green_led_off(p_slot);
                mutex_lock(&p_slot->lock);
                p_slot->state = STATIC_STATE;
                mutex_unlock(&p_slot->lock);
                break;
        default:
                break;
        }

        kfree(info);
}

static void pciehp_queue_power_work(struct slot *p_slot, int req)
{
        struct power_work_info *info;

        p_slot->state = (req == ENABLE_REQ) ? POWERON_STATE : POWEROFF_STATE;

        info = kmalloc(sizeof(*info), GFP_KERNEL);
        if (!info) {
                ctrl_err(p_slot->ctrl, "no memory to queue %s request\n",
                         (req == ENABLE_REQ) ? "poweron" : "poweroff");
                return;
        }
        info->p_slot = p_slot;
        INIT_WORK(&info->work, pciehp_power_thread);
        info->req = req;
        queue_work(p_slot->wq, &info->work);
}

void pciehp_queue_pushbutton_work(struct work_struct *work)
{
        struct slot *p_slot = container_of(work, struct slot, work.work);

        mutex_lock(&p_slot->lock);
        switch (p_slot->state) {
        case BLINKINGOFF_STATE:
                pciehp_queue_power_work(p_slot, DISABLE_REQ);
                break;
        case BLINKINGON_STATE:
                pciehp_queue_power_work(p_slot, ENABLE_REQ);
                break;
        default:
                break;
        }
        mutex_unlock(&p_slot->lock);
}

/*
 * Note: This function must be called with slot->lock held
 */
static void handle_button_press_event(struct slot *p_slot)
{
        struct controller *ctrl = p_slot->ctrl;
        u8 getstatus;

        switch (p_slot->state) {
        case STATIC_STATE:
                pciehp_get_power_status(p_slot, &getstatus);
                if (getstatus) {
                        p_slot->state = BLINKINGOFF_STATE;
                        ctrl_info(ctrl, "Slot(%s): Powering off due to button press\n",
                                  slot_name(p_slot));
                } else {
                        p_slot->state = BLINKINGON_STATE;
                        ctrl_info(ctrl, "Slot(%s) Powering on due to button press\n",
                                  slot_name(p_slot));
                }
                /* blink green LED and turn off amber */
                pciehp_green_led_blink(p_slot);
                pciehp_set_attention_status(p_slot, 0);
                queue_delayed_work(p_slot->wq, &p_slot->work, 5*HZ);
                break;
        case BLINKINGOFF_STATE:
        case BLINKINGON_STATE:
                /*
                 * Cancel if we are still blinking; this means that we
                 * press the attention again before the 5 sec. limit
                 * expires to cancel hot-add or hot-remove
                 */
                ctrl_info(ctrl, "Slot(%s): Button cancel\n", slot_name(p_slot));
                cancel_delayed_work(&p_slot->work);
                if (p_slot->state == BLINKINGOFF_STATE)
                        pciehp_green_led_on(p_slot);
                else
                        pciehp_green_led_off(p_slot);
                pciehp_set_attention_status(p_slot, 0);
                ctrl_info(ctrl, "Slot(%s): Action canceled due to button press\n",
                          slot_name(p_slot));
                p_slot->state = STATIC_STATE;
                break;
        case POWEROFF_STATE:
        case POWERON_STATE:
                /*
                 * Ignore if the slot is on power-on or power-off state;
                 * this means that the previous attention button action
                 * to hot-add or hot-remove is undergoing
                 */
                ctrl_info(ctrl, "Slot(%s): Button ignored\n",
                          slot_name(p_slot));
                break;
        default:
                ctrl_err(ctrl, "Slot(%s): Ignoring invalid state %#x\n",
                         slot_name(p_slot), p_slot->state);
                break;
        }
}

/*
 * Note: This function must be called with slot->lock held
 */
static void handle_link_event(struct slot *p_slot, u32 event)
{
        struct controller *ctrl = p_slot->ctrl;

        switch (p_slot->state) {
        case BLINKINGON_STATE:
        case BLINKINGOFF_STATE:
                cancel_delayed_work(&p_slot->work);
                /* Fall through */
        case STATIC_STATE:
                pciehp_queue_power_work(p_slot, event == INT_LINK_UP ?
                                        ENABLE_REQ : DISABLE_REQ);
                break;
        case POWERON_STATE:
                if (event == INT_LINK_UP) {
                        ctrl_info(ctrl, "Slot(%s): Link Up event ignored; already powering on\n",
                                  slot_name(p_slot));
                } else {
                        ctrl_info(ctrl, "Slot(%s): Link Down event queued; currently getting powered on\n",
                                  slot_name(p_slot));
                        pciehp_queue_power_work(p_slot, DISABLE_REQ);
                }
                break;
        case POWEROFF_STATE:
                if (event == INT_LINK_UP) {
                        ctrl_info(ctrl, "Slot(%s): Link Up event queued; currently getting powered off\n",
                                  slot_name(p_slot));
                        pciehp_queue_power_work(p_slot, ENABLE_REQ);
                } else {
                        ctrl_info(ctrl, "Slot(%s): Link Down event ignored; already powering off\n",
                                  slot_name(p_slot));
                }
                break;
        default:
                ctrl_err(ctrl, "Slot(%s): Ignoring invalid state %#x\n",
                         slot_name(p_slot), p_slot->state);
                break;
        }
}

static void interrupt_event_handler(struct work_struct *work)
{
        struct event_info *info = container_of(work, struct event_info, work);
        struct slot *p_slot = info->p_slot;
        struct controller *ctrl = p_slot->ctrl;

        mutex_lock(&p_slot->lock);
        switch (info->event_type) {
        case INT_BUTTON_PRESS:
                handle_button_press_event(p_slot);
                break;
        case INT_POWER_FAULT:
                if (!POWER_CTRL(ctrl))
                        break;
                pciehp_set_attention_status(p_slot, 1);
                pciehp_green_led_off(p_slot);
                break;
        case INT_PRESENCE_ON:
                pciehp_queue_power_work(p_slot, ENABLE_REQ);
                break;
        case INT_PRESENCE_OFF:
                /*
                 * Regardless of surprise capability, we need to
                 * definitely remove a card that has been pulled out!
                 */
                pciehp_queue_power_work(p_slot, DISABLE_REQ);
                break;
        case INT_LINK_UP:
        case INT_LINK_DOWN:
                handle_link_event(p_slot, info->event_type);
                break;
        default:
                break;
        }
        mutex_unlock(&p_slot->lock);

        kfree(info);
}

/*
 * Note: This function must be called with slot->hotplug_lock held
 */
int pciehp_enable_slot(struct slot *p_slot)
{
        u8 getstatus = 0;
        struct controller *ctrl = p_slot->ctrl;

        pciehp_get_adapter_status(p_slot, &getstatus);
        if (!getstatus) {
                ctrl_info(ctrl, "Slot(%s): No adapter\n", slot_name(p_slot));
                return -ENODEV;
        }
        if (MRL_SENS(p_slot->ctrl)) {
                pciehp_get_latch_status(p_slot, &getstatus);
                if (getstatus) {
                        ctrl_info(ctrl, "Slot(%s): Latch open\n",
                                  slot_name(p_slot));
                        return -ENODEV;
                }
        }

        if (POWER_CTRL(p_slot->ctrl)) {
                pciehp_get_power_status(p_slot, &getstatus);
                if (getstatus) {
                        ctrl_info(ctrl, "Slot(%s): Already enabled\n",
                                  slot_name(p_slot));
                        return 0;
                }
        }

        return board_added(p_slot);
}

/*
 * Note: This function must be called with slot->hotplug_lock held
 */
int pciehp_disable_slot(struct slot *p_slot)
{
        u8 getstatus = 0;
        struct controller *ctrl = p_slot->ctrl;

        if (!p_slot->ctrl)
                return 1;

        if (POWER_CTRL(p_slot->ctrl)) {
                pciehp_get_power_status(p_slot, &getstatus);
                if (!getstatus) {
                        ctrl_info(ctrl, "Slot(%s): Already disabled\n",
                                  slot_name(p_slot));
                        return -EINVAL;
                }
        }

        return remove_board(p_slot);
}

int pciehp_sysfs_enable_slot(struct slot *p_slot)
{
        int retval = -ENODEV;
        struct controller *ctrl = p_slot->ctrl;

        mutex_lock(&p_slot->lock);
        switch (p_slot->state) {
        case BLINKINGON_STATE:
                cancel_delayed_work(&p_slot->work);
        case STATIC_STATE:
                p_slot->state = POWERON_STATE;
                mutex_unlock(&p_slot->lock);
                mutex_lock(&p_slot->hotplug_lock);
                retval = pciehp_enable_slot(p_slot);
                mutex_unlock(&p_slot->hotplug_lock);
                mutex_lock(&p_slot->lock);
                p_slot->state = STATIC_STATE;
                break;
        case POWERON_STATE:
                ctrl_info(ctrl, "Slot(%s): Already in powering on state\n",
                          slot_name(p_slot));
                break;
        case BLINKINGOFF_STATE:
        case POWEROFF_STATE:
                ctrl_info(ctrl, "Slot(%s): Already enabled\n",
                          slot_name(p_slot));
                break;
        default:
                ctrl_err(ctrl, "Slot(%s): Invalid state %#x\n",
                         slot_name(p_slot), p_slot->state);
                break;
        }
        mutex_unlock(&p_slot->lock);

        return retval;
}

int pciehp_sysfs_disable_slot(struct slot *p_slot)
{
        int retval = -ENODEV;
        struct controller *ctrl = p_slot->ctrl;

        mutex_lock(&p_slot->lock);
        switch (p_slot->state) {
        case BLINKINGOFF_STATE:
                cancel_delayed_work(&p_slot->work);
        case STATIC_STATE:
                p_slot->state = POWEROFF_STATE;
                mutex_unlock(&p_slot->lock);
                mutex_lock(&p_slot->hotplug_lock);
                retval = pciehp_disable_slot(p_slot);
                mutex_unlock(&p_slot->hotplug_lock);
                mutex_lock(&p_slot->lock);
                p_slot->state = STATIC_STATE;
                break;
        case POWEROFF_STATE:
                ctrl_info(ctrl, "Slot(%s): Already in powering off state\n",
                          slot_name(p_slot));
                break;
        case BLINKINGON_STATE:
        case POWERON_STATE:
                ctrl_info(ctrl, "Slot(%s): Already disabled\n",
                          slot_name(p_slot));
                break;
        default:
                ctrl_err(ctrl, "Slot(%s): Invalid state %#x\n",
                         slot_name(p_slot), p_slot->state);
                break;
        }
        mutex_unlock(&p_slot->lock);

        return retval;
}