// 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>
 *
 * Authors:
 *   Dan Zink <dan.zink@compaq.com>
 *   Greg Kroah-Hartman <greg@kroah.com>
 *   Dely Sy <dely.l.sy@intel.com>"
 */

#define pr_fmt(fmt) "pciehp: " fmt
#define dev_fmt pr_fmt

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

#include "../pci.h"

/* Global variables */
bool pciehp_poll_mode;
int pciehp_poll_time;

/*
 * not really modular, but the easiest way to keep compat with existing
 * bootargs behaviour is to continue using module_param here.
 */
module_param(pciehp_poll_mode, bool, 0644);
module_param(pciehp_poll_time, int, 0644);
MODULE_PARM_DESC(pciehp_poll_mode, "Using polling mechanism for hot-plug events or not");
MODULE_PARM_DESC(pciehp_poll_time, "Polling mechanism frequency, in seconds");

static int set_attention_status(struct hotplug_slot *slot, u8 value);
static int get_power_status(struct hotplug_slot *slot, u8 *value);
static int get_latch_status(struct hotplug_slot *slot, u8 *value);
static int get_adapter_status(struct hotplug_slot *slot, u8 *value);

static int init_slot(struct controller *ctrl)
{
        struct hotplug_slot_ops *ops;
        char name[SLOT_NAME_SIZE];
        int retval;

        /* Setup hotplug slot ops */
        ops = kzalloc_obj(*ops);
        if (!ops)
                return -ENOMEM;

        ops->enable_slot = pciehp_sysfs_enable_slot;
        ops->disable_slot = pciehp_sysfs_disable_slot;
        ops->get_power_status = get_power_status;
        ops->get_adapter_status = get_adapter_status;
        ops->reset_slot = pciehp_reset_slot;
        if (MRL_SENS(ctrl))
                ops->get_latch_status = get_latch_status;
        if (ATTN_LED(ctrl)) {
                ops->get_attention_status = pciehp_get_attention_status;
                ops->set_attention_status = set_attention_status;
        } else if (ctrl->pcie->port->hotplug_user_indicators) {
                ops->get_attention_status = pciehp_get_raw_indicator_status;
                ops->set_attention_status = pciehp_set_raw_indicator_status;
        }

        /* register this slot with the hotplug pci core */
        ctrl->hotplug_slot.ops = ops;
        snprintf(name, SLOT_NAME_SIZE, "%u", PSN(ctrl));

        retval = pci_hp_initialize(&ctrl->hotplug_slot,
                                   ctrl->pcie->port->subordinate, 0, name);
        if (retval) {
                ctrl_err(ctrl, "pci_hp_initialize failed: error %d\n", retval);
                kfree(ops);
        }
        return retval;
}

static void cleanup_slot(struct controller *ctrl)
{
        struct hotplug_slot *hotplug_slot = &ctrl->hotplug_slot;

        pci_hp_destroy(hotplug_slot);
        kfree(hotplug_slot->ops);
}

/*
 * set_attention_status - Turns the Attention Indicator on, off or blinking
 */
static int set_attention_status(struct hotplug_slot *hotplug_slot, u8 status)
{
        struct controller *ctrl = to_ctrl(hotplug_slot);
        struct pci_dev *pdev = ctrl->pcie->port;

        if (status)
                status = FIELD_PREP(PCI_EXP_SLTCTL_AIC, status);
        else
                status = PCI_EXP_SLTCTL_ATTN_IND_OFF;

        pci_config_pm_runtime_get(pdev);
        pciehp_set_indicators(ctrl, INDICATOR_NOOP, status);
        pci_config_pm_runtime_put(pdev);
        return 0;
}

static int get_power_status(struct hotplug_slot *hotplug_slot, u8 *value)
{
        struct controller *ctrl = to_ctrl(hotplug_slot);
        struct pci_dev *pdev = ctrl->pcie->port;

        pci_config_pm_runtime_get(pdev);
        pciehp_get_power_status(ctrl, value);
        pci_config_pm_runtime_put(pdev);
        return 0;
}

static int get_latch_status(struct hotplug_slot *hotplug_slot, u8 *value)
{
        struct controller *ctrl = to_ctrl(hotplug_slot);
        struct pci_dev *pdev = ctrl->pcie->port;

        pci_config_pm_runtime_get(pdev);
        pciehp_get_latch_status(ctrl, value);
        pci_config_pm_runtime_put(pdev);
        return 0;
}

static int get_adapter_status(struct hotplug_slot *hotplug_slot, u8 *value)
{
        struct controller *ctrl = to_ctrl(hotplug_slot);
        struct pci_dev *pdev = ctrl->pcie->port;
        int ret;

        pci_config_pm_runtime_get(pdev);
        ret = pciehp_card_present_or_link_active(ctrl);
        pci_config_pm_runtime_put(pdev);
        if (ret < 0)
                return ret;

        *value = ret;
        return 0;
}

/**
 * pciehp_check_presence() - synthesize event if presence has changed
 * @ctrl: controller to check
 *
 * On probe and resume, an explicit presence check is necessary to bring up an
 * occupied slot or bring down an unoccupied slot.  This can't be triggered by
 * events in the Slot Status register, they may be stale and are therefore
 * cleared.  Secondly, sending an interrupt for "events that occur while
 * interrupt generation is disabled [when] interrupt generation is subsequently
 * enabled" is optional per PCIe r4.0, sec 6.7.3.4.
 */
static void pciehp_check_presence(struct controller *ctrl)
{
        int occupied;

        down_read_nested(&ctrl->reset_lock, ctrl->depth);
        mutex_lock(&ctrl->state_lock);

        occupied = pciehp_card_present_or_link_active(ctrl);
        if ((occupied > 0 && (ctrl->state == OFF_STATE ||
                          ctrl->state == BLINKINGON_STATE)) ||
            (!occupied && (ctrl->state == ON_STATE ||
                           ctrl->state == BLINKINGOFF_STATE)))
                pciehp_request(ctrl, PCI_EXP_SLTSTA_PDC);

        mutex_unlock(&ctrl->state_lock);
        up_read(&ctrl->reset_lock);
}

static int pciehp_probe(struct pcie_device *dev)
{
        int rc;
        struct controller *ctrl;

        /* If this is not a "hotplug" service, we have no business here. */
        if (dev->service != PCIE_PORT_SERVICE_HP)
                return -ENODEV;

        if (!dev->port->subordinate) {
                /* Can happen if we run out of bus numbers during probe */
                pci_err(dev->port,
                        "Hotplug bridge without secondary bus, ignoring\n");
                return -ENODEV;
        }

        ctrl = pcie_init(dev);
        if (!ctrl) {
                pci_err(dev->port, "Controller initialization failed\n");
                return -ENODEV;
        }
        set_service_data(dev, ctrl);

        /* Setup the slot information structures */
        rc = init_slot(ctrl);
        if (rc) {
                if (rc == -EBUSY)
                        ctrl_warn(ctrl, "Slot already registered by another hotplug driver\n");
                else
                        ctrl_err(ctrl, "Slot initialization failed (%d)\n", rc);
                goto err_out_release_ctlr;
        }

        /* Enable events after we have setup the data structures */
        rc = pcie_init_notification(ctrl);
        if (rc) {
                ctrl_err(ctrl, "Notification initialization failed (%d)\n", rc);
                goto err_out_free_ctrl_slot;
        }

        /* Publish to user space */
        rc = pci_hp_add(&ctrl->hotplug_slot);
        if (rc) {
                ctrl_err(ctrl, "Publication to user space failed (%d)\n", rc);
                goto err_out_shutdown_notification;
        }

        pciehp_check_presence(ctrl);

        return 0;

err_out_shutdown_notification:
        pcie_shutdown_notification(ctrl);
err_out_free_ctrl_slot:
        cleanup_slot(ctrl);
err_out_release_ctlr:
        pciehp_release_ctrl(ctrl);
        return -ENODEV;
}

static void pciehp_remove(struct pcie_device *dev)
{
        struct controller *ctrl = get_service_data(dev);

        pci_hp_del(&ctrl->hotplug_slot);
        pcie_shutdown_notification(ctrl);
        cleanup_slot(ctrl);
        pciehp_release_ctrl(ctrl);
}

#ifdef CONFIG_PM
static bool pme_is_native(struct pcie_device *dev)
{
        const struct pci_host_bridge *host;

        host = pci_find_host_bridge(dev->port->bus);
        return pcie_ports_native || host->native_pme;
}

static void pciehp_disable_interrupt(struct pcie_device *dev)
{
        /*
         * Disable hotplug interrupt so that it does not trigger
         * immediately when the downstream link goes down.
         */
        if (pme_is_native(dev))
                pcie_disable_interrupt(get_service_data(dev));
}

#ifdef CONFIG_PM_SLEEP
static int pciehp_suspend(struct pcie_device *dev)
{
        /*
         * If the port is already runtime suspended we can keep it that
         * way.
         */
        if (dev_pm_skip_suspend(&dev->port->dev))
                return 0;

        pciehp_disable_interrupt(dev);
        return 0;
}

static int pciehp_resume_noirq(struct pcie_device *dev)
{
        struct controller *ctrl = get_service_data(dev);

        /* pci_restore_state() just wrote to the Slot Control register */
        ctrl->cmd_started = jiffies;
        ctrl->cmd_busy = true;

        /* clear spurious events from rediscovery of inserted card */
        if (ctrl->state == ON_STATE || ctrl->state == BLINKINGOFF_STATE) {
                pcie_clear_hotplug_events(ctrl);

                /*
                 * If hotplugged device was replaced with a different one
                 * during system sleep, mark the old device disconnected
                 * (to prevent its driver from accessing the new device)
                 * and synthesize a Presence Detect Changed event.
                 */
                if (pciehp_device_replaced(ctrl)) {
                        ctrl_dbg(ctrl, "device replaced during system sleep\n");
                        pci_walk_bus(ctrl->pcie->port->subordinate,
                                     pci_dev_set_disconnected, NULL);
                        pciehp_request(ctrl, PCI_EXP_SLTSTA_PDC);
                }
        }

        return 0;
}
#endif

static int pciehp_resume(struct pcie_device *dev)
{
        struct controller *ctrl = get_service_data(dev);

        if (pme_is_native(dev))
                pcie_enable_interrupt(ctrl);

        pciehp_check_presence(ctrl);

        return 0;
}

static int pciehp_runtime_suspend(struct pcie_device *dev)
{
        pciehp_disable_interrupt(dev);
        return 0;
}

static int pciehp_runtime_resume(struct pcie_device *dev)
{
        struct controller *ctrl = get_service_data(dev);

        /* pci_restore_state() just wrote to the Slot Control register */
        ctrl->cmd_started = jiffies;
        ctrl->cmd_busy = true;

        /* clear spurious events from rediscovery of inserted card */
        if ((ctrl->state == ON_STATE || ctrl->state == BLINKINGOFF_STATE) &&
             pme_is_native(dev))
                pcie_clear_hotplug_events(ctrl);

        return pciehp_resume(dev);
}
#endif /* PM */

static struct pcie_port_service_driver hpdriver_portdrv = {
        .name           = "pciehp",
        .port_type      = PCIE_ANY_PORT,
        .service        = PCIE_PORT_SERVICE_HP,

        .probe          = pciehp_probe,
        .remove         = pciehp_remove,

#ifdef  CONFIG_PM
#ifdef  CONFIG_PM_SLEEP
        .suspend        = pciehp_suspend,
        .resume_noirq   = pciehp_resume_noirq,
        .resume         = pciehp_resume,
#endif
        .runtime_suspend = pciehp_runtime_suspend,
        .runtime_resume = pciehp_runtime_resume,
#endif  /* PM */

        .slot_reset     = pciehp_slot_reset,
};

int __init pcie_hp_init(void)
{
        int retval = 0;

        retval = pcie_port_service_register(&hpdriver_portdrv);
        pr_debug("pcie_port_service_register = %d\n", retval);
        if (retval)
                pr_debug("Failure to register service\n");

        return retval;
}