// SPDX-License-Identifier: GPL-2.0
/*
 * Cadence USBSS PCI Glue driver
 *
 * Copyright (C) 2018-2019 Cadence.
 *
 * Author: Pawel Laszczak <pawell@cadence.com>
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/pci.h>
#include <linux/platform_device.h>
#include <linux/dma-mapping.h>
#include <linux/slab.h>

struct cdns3_wrap {
        struct platform_device *plat_dev;
        struct resource dev_res[6];
        int devfn;
};

#define RES_IRQ_HOST_ID         0
#define RES_IRQ_PERIPHERAL_ID   1
#define RES_IRQ_OTG_ID          2
#define RES_HOST_ID             3
#define RES_DEV_ID              4
#define RES_DRD_ID              5

#define PCI_BAR_HOST            0
#define PCI_BAR_DEV             2
#define PCI_BAR_OTG             0

#define PCI_DEV_FN_HOST_DEVICE  0
#define PCI_DEV_FN_OTG          1

#define PCI_DRIVER_NAME         "cdns3-pci-usbss"
#define PLAT_DRIVER_NAME        "cdns-usb3"

static struct pci_dev *cdns3_get_second_fun(struct pci_dev *pdev)
{
        struct pci_dev *func;

        /*
         * Gets the second function.
         * It's little tricky, but this platform has two function.
         * The fist keeps resources for Host/Device while the second
         * keeps resources for DRD/OTG.
         */
        func = pci_get_device(pdev->vendor, pdev->device, NULL);
        if (unlikely(!func))
                return NULL;

        if (func->devfn == pdev->devfn) {
                func = pci_get_device(pdev->vendor, pdev->device, func);
                if (unlikely(!func))
                        return NULL;
        }

        if (func->devfn != PCI_DEV_FN_HOST_DEVICE &&
            func->devfn != PCI_DEV_FN_OTG) {
                return NULL;
        }

        return func;
}

static int cdns3_pci_probe(struct pci_dev *pdev,
                           const struct pci_device_id *id)
{
        struct platform_device_info plat_info;
        struct cdns3_wrap *wrap;
        struct resource *res;
        struct pci_dev *func;
        int err;

        /*
         * for GADGET/HOST PCI (devfn) function number is 0,
         * for OTG PCI (devfn) function number is 1
         */
        if (!id || (pdev->devfn != PCI_DEV_FN_HOST_DEVICE &&
                    pdev->devfn != PCI_DEV_FN_OTG))
                return -EINVAL;

        func = cdns3_get_second_fun(pdev);
        if (unlikely(!func))
                return -EINVAL;

        err = pcim_enable_device(pdev);
        if (err) {
                dev_err(&pdev->dev, "Enabling PCI device has failed %d\n", err);
                return err;
        }

        pci_set_master(pdev);

        if (pci_is_enabled(func)) {
                wrap = pci_get_drvdata(func);
        } else {
                wrap = kzalloc_obj(*wrap);
                if (!wrap)
                        return -ENOMEM;
        }

        res = wrap->dev_res;

        if (pdev->devfn == PCI_DEV_FN_HOST_DEVICE) {
                /* function 0: host(BAR_0) + device(BAR_1).*/
                dev_dbg(&pdev->dev, "Initialize Device resources\n");
                res[RES_DEV_ID].start = pci_resource_start(pdev, PCI_BAR_DEV);
                res[RES_DEV_ID].end =   pci_resource_end(pdev, PCI_BAR_DEV);
                res[RES_DEV_ID].name = "dev";
                res[RES_DEV_ID].flags = IORESOURCE_MEM;
                dev_dbg(&pdev->dev, "USBSS-DEV physical base addr: %pa\n",
                        &res[RES_DEV_ID].start);

                res[RES_HOST_ID].start = pci_resource_start(pdev, PCI_BAR_HOST);
                res[RES_HOST_ID].end = pci_resource_end(pdev, PCI_BAR_HOST);
                res[RES_HOST_ID].name = "xhci";
                res[RES_HOST_ID].flags = IORESOURCE_MEM;
                dev_dbg(&pdev->dev, "USBSS-XHCI physical base addr: %pa\n",
                        &res[RES_HOST_ID].start);

                /* Interrupt for XHCI */
                wrap->dev_res[RES_IRQ_HOST_ID].start = pdev->irq;
                wrap->dev_res[RES_IRQ_HOST_ID].name = "host";
                wrap->dev_res[RES_IRQ_HOST_ID].flags = IORESOURCE_IRQ;

                /* Interrupt device. It's the same as for HOST. */
                wrap->dev_res[RES_IRQ_PERIPHERAL_ID].start = pdev->irq;
                wrap->dev_res[RES_IRQ_PERIPHERAL_ID].name = "peripheral";
                wrap->dev_res[RES_IRQ_PERIPHERAL_ID].flags = IORESOURCE_IRQ;
        } else {
                res[RES_DRD_ID].start = pci_resource_start(pdev, PCI_BAR_OTG);
                res[RES_DRD_ID].end =   pci_resource_end(pdev, PCI_BAR_OTG);
                res[RES_DRD_ID].name = "otg";
                res[RES_DRD_ID].flags = IORESOURCE_MEM;
                dev_dbg(&pdev->dev, "USBSS-DRD physical base addr: %pa\n",
                        &res[RES_DRD_ID].start);

                /* Interrupt for OTG/DRD. */
                wrap->dev_res[RES_IRQ_OTG_ID].start = pdev->irq;
                wrap->dev_res[RES_IRQ_OTG_ID].name = "otg";
                wrap->dev_res[RES_IRQ_OTG_ID].flags = IORESOURCE_IRQ;
        }

        if (pci_is_enabled(func)) {
                /* set up platform device info */
                memset(&plat_info, 0, sizeof(plat_info));
                plat_info.parent = &pdev->dev;
                plat_info.fwnode = pdev->dev.fwnode;
                plat_info.name = PLAT_DRIVER_NAME;
                plat_info.id = pdev->devfn;
                wrap->devfn  = pdev->devfn;
                plat_info.res = wrap->dev_res;
                plat_info.num_res = ARRAY_SIZE(wrap->dev_res);
                plat_info.dma_mask = pdev->dma_mask;
                /* register platform device */
                wrap->plat_dev = platform_device_register_full(&plat_info);
                if (IS_ERR(wrap->plat_dev)) {
                        err = PTR_ERR(wrap->plat_dev);
                        kfree(wrap);
                        return err;
                }
        }

        pci_set_drvdata(pdev, wrap);
        return err;
}

static void cdns3_pci_remove(struct pci_dev *pdev)
{
        struct cdns3_wrap *wrap;
        struct pci_dev *func;

        func = cdns3_get_second_fun(pdev);

        wrap = (struct cdns3_wrap *)pci_get_drvdata(pdev);
        if (wrap->devfn == pdev->devfn)
                platform_device_unregister(wrap->plat_dev);

        if (!pci_is_enabled(func))
                kfree(wrap);
}

static const struct pci_device_id cdns3_pci_ids[] = {
        { PCI_VDEVICE(CDNS, PCI_DEVICE_ID_CDNS_USBSS) },
        { 0, }
};

static struct pci_driver cdns3_pci_driver = {
        .name = PCI_DRIVER_NAME,
        .id_table = cdns3_pci_ids,
        .probe = cdns3_pci_probe,
        .remove = cdns3_pci_remove,
};

module_pci_driver(cdns3_pci_driver);
MODULE_DEVICE_TABLE(pci, cdns3_pci_ids);

MODULE_AUTHOR("Pawel Laszczak <pawell@cadence.com>");
MODULE_LICENSE("GPL v2");
MODULE_DESCRIPTION("Cadence USBSS PCI wrapper");