/*
 * File:        portdrv_pci.c
 * Purpose:     PCI Express Port Bus Driver
 *
 * Copyright (C) 2004 Intel
 * Copyright (C) Tom Long Nguyen (tom.l.nguyen@intel.com)
 */

#include <linux/module.h>
#include <linux/pci.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/pm.h>
#include <linux/pm_runtime.h>
#include <linux/init.h>
#include <linux/pcieport_if.h>
#include <linux/aer.h>
#include <linux/dmi.h>
#include <linux/pci-aspm.h>

#include "portdrv.h"
#include "aer/aerdrv.h"

/*
 * Version Information
 */
#define DRIVER_VERSION "v1.0"
#define DRIVER_AUTHOR "tom.l.nguyen@intel.com"
#define DRIVER_DESC "PCIe Port Bus Driver"
MODULE_AUTHOR(DRIVER_AUTHOR);
MODULE_DESCRIPTION(DRIVER_DESC);
MODULE_LICENSE("GPL");

/* If this switch is set, PCIe port native services should not be enabled. */
bool pcie_ports_disabled;

/*
 * If this switch is set, ACPI _OSC will be used to determine whether or not to
 * enable PCIe port native services.
 */
bool pcie_ports_auto = true;

static int __init pcie_port_setup(char *str)
{
        if (!strncmp(str, "compat", 6)) {
                pcie_ports_disabled = true;
        } else if (!strncmp(str, "native", 6)) {
                pcie_ports_disabled = false;
                pcie_ports_auto = false;
        } else if (!strncmp(str, "auto", 4)) {
                pcie_ports_disabled = false;
                pcie_ports_auto = true;
        }

        return 1;
}
__setup("pcie_ports=", pcie_port_setup);

/* global data */

/**
 * pcie_clear_root_pme_status - Clear root port PME interrupt status.
 * @dev: PCIe root port or event collector.
 */
void pcie_clear_root_pme_status(struct pci_dev *dev)
{
        pcie_capability_set_dword(dev, PCI_EXP_RTSTA, PCI_EXP_RTSTA_PME);
}

static int pcie_portdrv_restore_config(struct pci_dev *dev)
{
        int retval;

        retval = pci_enable_device(dev);
        if (retval)
                return retval;
        pci_set_master(dev);
        return 0;
}

#ifdef CONFIG_PM
static int pcie_port_resume_noirq(struct device *dev)
{
        struct pci_dev *pdev = to_pci_dev(dev);

        /*
         * Some BIOSes forget to clear Root PME Status bits after system wakeup
         * which breaks ACPI-based runtime wakeup on PCI Express, so clear those
         * bits now just in case (shouldn't hurt).
         */
        if (pci_pcie_type(pdev) == PCI_EXP_TYPE_ROOT_PORT)
                pcie_clear_root_pme_status(pdev);
        return 0;
}

#ifdef CONFIG_PM_RUNTIME
struct d3cold_info {
        bool no_d3cold;
        unsigned int d3cold_delay;
};

static int pci_dev_d3cold_info(struct pci_dev *pdev, void *data)
{
        struct d3cold_info *info = data;

        info->d3cold_delay = max_t(unsigned int, pdev->d3cold_delay,
                                   info->d3cold_delay);
        if (pdev->no_d3cold)
                info->no_d3cold = true;
        return 0;
}

static int pcie_port_runtime_suspend(struct device *dev)
{
        struct pci_dev *pdev = to_pci_dev(dev);
        struct d3cold_info d3cold_info = {
                .no_d3cold      = false,
                .d3cold_delay   = PCI_PM_D3_WAIT,
        };

        /*
         * If any subordinate device disable D3cold, we should not put
         * the port into D3cold.  The D3cold delay of port should be
         * the max of that of all subordinate devices.
         */
        pci_walk_bus(pdev->subordinate, pci_dev_d3cold_info, &d3cold_info);
        pdev->no_d3cold = d3cold_info.no_d3cold;
        pdev->d3cold_delay = d3cold_info.d3cold_delay;
        return 0;
}

static int pcie_port_runtime_resume(struct device *dev)
{
        return 0;
}

static int pci_dev_pme_poll(struct pci_dev *pdev, void *data)
{
        bool *pme_poll = data;

        if (pdev->pme_poll)
                *pme_poll = true;
        return 0;
}

static int pcie_port_runtime_idle(struct device *dev)
{
        struct pci_dev *pdev = to_pci_dev(dev);
        bool pme_poll = false;

        /*
         * If any subordinate device needs pme poll, we should keep
         * the port in D0, because we need port in D0 to poll it.
         */
        pci_walk_bus(pdev->subordinate, pci_dev_pme_poll, &pme_poll);
        /* Delay for a short while to prevent too frequent suspend/resume */
        if (!pme_poll)
                pm_schedule_suspend(dev, 10);
        return -EBUSY;
}
#else
#define pcie_port_runtime_suspend       NULL
#define pcie_port_runtime_resume        NULL
#define pcie_port_runtime_idle          NULL
#endif

static const struct dev_pm_ops pcie_portdrv_pm_ops = {
        .suspend        = pcie_port_device_suspend,
        .resume         = pcie_port_device_resume,
        .freeze         = pcie_port_device_suspend,
        .thaw           = pcie_port_device_resume,
        .poweroff       = pcie_port_device_suspend,
        .restore        = pcie_port_device_resume,
        .resume_noirq   = pcie_port_resume_noirq,
        .runtime_suspend = pcie_port_runtime_suspend,
        .runtime_resume = pcie_port_runtime_resume,
        .runtime_idle   = pcie_port_runtime_idle,
};

#define PCIE_PORTDRV_PM_OPS     (&pcie_portdrv_pm_ops)

#else /* !PM */

#define PCIE_PORTDRV_PM_OPS     NULL
#endif /* !PM */

/*
 * pcie_portdrv_probe - Probe PCI-Express port devices
 * @dev: PCI-Express port device being probed
 *
 * If detected invokes the pcie_port_device_register() method for
 * this port device.
 *
 */
static int pcie_portdrv_probe(struct pci_dev *dev,
                                        const struct pci_device_id *id)
{
        int status;

        if (!pci_is_pcie(dev) ||
            ((pci_pcie_type(dev) != PCI_EXP_TYPE_ROOT_PORT) &&
             (pci_pcie_type(dev) != PCI_EXP_TYPE_UPSTREAM) &&
             (pci_pcie_type(dev) != PCI_EXP_TYPE_DOWNSTREAM)))
                return -ENODEV;

        if (!dev->irq && dev->pin) {
                dev_warn(&dev->dev, "device [%04x:%04x] has invalid IRQ; "
                         "check vendor BIOS\n", dev->vendor, dev->device);
        }
        status = pcie_port_device_register(dev);
        if (status)
                return status;

        pci_save_state(dev);
        /*
         * D3cold may not work properly on some PCIe port, so disable
         * it by default.
         */
        dev->d3cold_allowed = false;
        return 0;
}

static void pcie_portdrv_remove(struct pci_dev *dev)
{
        pcie_port_device_remove(dev);
        pci_disable_device(dev);
}

static int error_detected_iter(struct device *device, void *data)
{
        struct pcie_device *pcie_device;
        struct pcie_port_service_driver *driver;
        struct aer_broadcast_data *result_data;
        pci_ers_result_t status;

        result_data = (struct aer_broadcast_data *) data;

        if (device->bus == &pcie_port_bus_type && device->driver) {
                driver = to_service_driver(device->driver);
                if (!driver ||
                        !driver->err_handler ||
                        !driver->err_handler->error_detected)
                        return 0;

                pcie_device = to_pcie_device(device);

                /* Forward error detected message to service drivers */
                status = driver->err_handler->error_detected(
                        pcie_device->port,
                        result_data->state);
                result_data->result =
                        merge_result(result_data->result, status);
        }

        return 0;
}

static pci_ers_result_t pcie_portdrv_error_detected(struct pci_dev *dev,
                                        enum pci_channel_state error)
{
        struct aer_broadcast_data data = {error, PCI_ERS_RESULT_CAN_RECOVER};

        /* get true return value from &data */
        device_for_each_child(&dev->dev, &data, error_detected_iter);
        return data.result;
}

static int mmio_enabled_iter(struct device *device, void *data)
{
        struct pcie_device *pcie_device;
        struct pcie_port_service_driver *driver;
        pci_ers_result_t status, *result;

        result = (pci_ers_result_t *) data;

        if (device->bus == &pcie_port_bus_type && device->driver) {
                driver = to_service_driver(device->driver);
                if (driver &&
                        driver->err_handler &&
                        driver->err_handler->mmio_enabled) {
                        pcie_device = to_pcie_device(device);

                        /* Forward error message to service drivers */
                        status = driver->err_handler->mmio_enabled(
                                        pcie_device->port);
                        *result = merge_result(*result, status);
                }
        }

        return 0;
}

static pci_ers_result_t pcie_portdrv_mmio_enabled(struct pci_dev *dev)
{
        pci_ers_result_t status = PCI_ERS_RESULT_RECOVERED;

        /* get true return value from &status */
        device_for_each_child(&dev->dev, &status, mmio_enabled_iter);
        return status;
}

static int slot_reset_iter(struct device *device, void *data)
{
        struct pcie_device *pcie_device;
        struct pcie_port_service_driver *driver;
        pci_ers_result_t status, *result;

        result = (pci_ers_result_t *) data;

        if (device->bus == &pcie_port_bus_type && device->driver) {
                driver = to_service_driver(device->driver);
                if (driver &&
                        driver->err_handler &&
                        driver->err_handler->slot_reset) {
                        pcie_device = to_pcie_device(device);

                        /* Forward error message to service drivers */
                        status = driver->err_handler->slot_reset(
                                        pcie_device->port);
                        *result = merge_result(*result, status);
                }
        }

        return 0;
}

static pci_ers_result_t pcie_portdrv_slot_reset(struct pci_dev *dev)
{
        pci_ers_result_t status = PCI_ERS_RESULT_RECOVERED;

        /* If fatal, restore cfg space for possible link reset at upstream */
        if (dev->error_state == pci_channel_io_frozen) {
                dev->state_saved = true;
                pci_restore_state(dev);
                pcie_portdrv_restore_config(dev);
                pci_enable_pcie_error_reporting(dev);
        }

        /* get true return value from &status */
        device_for_each_child(&dev->dev, &status, slot_reset_iter);
        return status;
}

static int resume_iter(struct device *device, void *data)
{
        struct pcie_device *pcie_device;
        struct pcie_port_service_driver *driver;

        if (device->bus == &pcie_port_bus_type && device->driver) {
                driver = to_service_driver(device->driver);
                if (driver &&
                        driver->err_handler &&
                        driver->err_handler->resume) {
                        pcie_device = to_pcie_device(device);

                        /* Forward error message to service drivers */
                        driver->err_handler->resume(pcie_device->port);
                }
        }

        return 0;
}

static void pcie_portdrv_err_resume(struct pci_dev *dev)
{
        device_for_each_child(&dev->dev, NULL, resume_iter);
}

/*
 * LINUX Device Driver Model
 */
static const struct pci_device_id port_pci_ids[] = { {
        /* handle any PCI-Express port */
        PCI_DEVICE_CLASS(((PCI_CLASS_BRIDGE_PCI << 8) | 0x00), ~0),
        }, { /* end: all zeroes */ }
};
MODULE_DEVICE_TABLE(pci, port_pci_ids);

static const struct pci_error_handlers pcie_portdrv_err_handler = {
        .error_detected = pcie_portdrv_error_detected,
        .mmio_enabled = pcie_portdrv_mmio_enabled,
        .slot_reset = pcie_portdrv_slot_reset,
        .resume = pcie_portdrv_err_resume,
};

static struct pci_driver pcie_portdriver = {
        .name           = "pcieport",
        .id_table       = &port_pci_ids[0],

        .probe          = pcie_portdrv_probe,
        .remove         = pcie_portdrv_remove,

        .err_handler    = &pcie_portdrv_err_handler,

        .driver.pm      = PCIE_PORTDRV_PM_OPS,
};

static int __init dmi_pcie_pme_disable_msi(const struct dmi_system_id *d)
{
        pr_notice("%s detected: will not use MSI for PCIe PME signaling\n",
                        d->ident);
        pcie_pme_disable_msi();
        return 0;
}

static struct dmi_system_id __initdata pcie_portdrv_dmi_table[] = {
        /*
         * Boxes that should not use MSI for PCIe PME signaling.
         */
        {
         .callback = dmi_pcie_pme_disable_msi,
         .ident = "MSI Wind U-100",
         .matches = {
                     DMI_MATCH(DMI_SYS_VENDOR,
                                "MICRO-STAR INTERNATIONAL CO., LTD"),
                     DMI_MATCH(DMI_PRODUCT_NAME, "U-100"),
                     },
         },
         {}
};

static int __init pcie_portdrv_init(void)
{
        int retval;

        if (pcie_ports_disabled)
                return pci_register_driver(&pcie_portdriver);

        dmi_check_system(pcie_portdrv_dmi_table);

        retval = pcie_port_bus_register();
        if (retval) {
                printk(KERN_WARNING "PCIE: bus_register error: %d\n", retval);
                goto out;
        }
        retval = pci_register_driver(&pcie_portdriver);
        if (retval)
                pcie_port_bus_unregister();
 out:
        return retval;
}

module_init(pcie_portdrv_init);