// SPDX-License-Identifier: GPL-2.0-only
/******************************************************************************
 * platform-pci.c
 *
 * Xen platform PCI device driver
 *
 * Authors: ssmith@xensource.com and stefano.stabellini@eu.citrix.com
 *
 * Copyright (c) 2005, Intel Corporation.
 * Copyright (c) 2007, XenSource Inc.
 * Copyright (c) 2010, Citrix
 */


#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/init.h>
#include <linux/pci.h>

#include <xen/platform_pci.h>
#include <xen/grant_table.h>
#include <xen/xenbus.h>
#include <xen/events.h>
#include <xen/hvm.h>
#include <xen/xen-ops.h>

#define DRV_NAME    "xen-platform-pci"

#define PCI_DEVICE_ID_XEN_PLATFORM_XS61 0x0002

static unsigned long platform_mmio;
static unsigned long platform_mmio_alloc;
static unsigned long platform_mmiolen;
static uint64_t callback_via;

static unsigned long alloc_xen_mmio(unsigned long len)
{
        unsigned long addr;

        addr = platform_mmio + platform_mmio_alloc;
        platform_mmio_alloc += len;
        BUG_ON(platform_mmio_alloc > platform_mmiolen);

        return addr;
}

static uint64_t get_callback_via(struct pci_dev *pdev)
{
        u8 pin;
        int irq;

        irq = pdev->irq;
        if (irq < 16)
                return irq; /* ISA IRQ */

        pin = pdev->pin;

        /* We don't know the GSI. Specify the PCI INTx line instead. */
        return ((uint64_t)HVM_PARAM_CALLBACK_TYPE_PCI_INTX <<
                          HVM_CALLBACK_VIA_TYPE_SHIFT) |
                ((uint64_t)pci_domain_nr(pdev->bus) << 32) |
                ((uint64_t)pdev->bus->number << 16) |
                ((uint64_t)(pdev->devfn & 0xff) << 8) |
                ((uint64_t)(pin - 1) & 3);
}

static irqreturn_t do_hvm_evtchn_intr(int irq, void *dev_id)
{
        return xen_evtchn_do_upcall();
}

static int xen_allocate_irq(struct pci_dev *pdev)
{
        return request_irq(pdev->irq, do_hvm_evtchn_intr,
                        IRQF_NOBALANCING | IRQF_SHARED,
                        "xen-platform-pci", pdev);
}

static int platform_pci_resume(struct device *dev)
{
        int err;

        if (xen_have_vector_callback)
                return 0;

        err = xen_set_callback_via(callback_via);
        if (err) {
                dev_err(dev, "platform_pci_resume failure!\n");
                return err;
        }
        return 0;
}

static int platform_pci_probe(struct pci_dev *pdev,
                              const struct pci_device_id *ent)
{
        int i, ret;
        long ioaddr;
        long mmio_addr, mmio_len;
        unsigned int max_nr_gframes;
        unsigned long grant_frames;

        if (!xen_domain())
                return -ENODEV;

        i = pci_enable_device(pdev);
        if (i)
                return i;

        ioaddr = pci_resource_start(pdev, 0);

        mmio_addr = pci_resource_start(pdev, 1);
        mmio_len = pci_resource_len(pdev, 1);

        if (mmio_addr == 0 || ioaddr == 0) {
                dev_err(&pdev->dev, "no resources found\n");
                ret = -ENOENT;
                goto pci_out;
        }

        ret = pci_request_region(pdev, 1, DRV_NAME);
        if (ret < 0)
                goto pci_out;

        ret = pci_request_region(pdev, 0, DRV_NAME);
        if (ret < 0)
                goto mem_out;

        platform_mmio = mmio_addr;
        platform_mmiolen = mmio_len;
        if (!xen_have_vector_callback) {
                ret = xen_allocate_irq(pdev);
                if (ret) {
                        dev_warn(&pdev->dev, "request_irq failed err=%d\n", ret);
                        goto out;
                }
                /*
                 * It doesn't strictly *have* to run on CPU0 but it sure
                 * as hell better process the event channel ports delivered
                 * to CPU0.
                 */
                irq_set_affinity(pdev->irq, cpumask_of(0));

                callback_via = get_callback_via(pdev);
                ret = xen_set_callback_via(callback_via);
                if (ret) {
                        dev_warn(&pdev->dev, "Unable to set the evtchn callback "
                                         "err=%d\n", ret);
                        goto irq_out;
                }
        }

        max_nr_gframes = gnttab_max_grant_frames();
        grant_frames = alloc_xen_mmio(PAGE_SIZE * max_nr_gframes);
        ret = gnttab_setup_auto_xlat_frames(grant_frames);
        if (ret)
                goto irq_out;
        ret = gnttab_init();
        if (ret)
                goto grant_out;
        return 0;
grant_out:
        gnttab_free_auto_xlat_frames();
irq_out:
        if (!xen_have_vector_callback)
                free_irq(pdev->irq, pdev);
out:
        pci_release_region(pdev, 0);
mem_out:
        pci_release_region(pdev, 1);
pci_out:
        pci_disable_device(pdev);
        return ret;
}

static const struct pci_device_id platform_pci_tbl[] = {
        { PCI_VDEVICE(XEN, PCI_DEVICE_ID_XEN_PLATFORM) },
        { PCI_VDEVICE(XEN, PCI_DEVICE_ID_XEN_PLATFORM_XS61) },
        { }
};

static const struct dev_pm_ops platform_pm_ops = {
        .resume_noirq =   platform_pci_resume,
};

static struct pci_driver platform_driver = {
        .name =           DRV_NAME,
        .probe =          platform_pci_probe,
        .id_table =       platform_pci_tbl,
        .driver = {
                .pm =     &platform_pm_ops,
        },
};

builtin_pci_driver(platform_driver);