// SPDX-License-Identifier: GPL-2.0
/*
 * PCI Backend - Handle special overlays for broken devices.
 *
 * Author: Ryan Wilson <hap9@epoch.ncsc.mil>
 * Author: Chris Bookholt <hap10@epoch.ncsc.mil>
 */

#define dev_fmt(fmt) DRV_NAME ": " fmt

#include <linux/kernel.h>
#include <linux/pci.h>
#include "pciback.h"
#include "conf_space.h"
#include "conf_space_quirks.h"

LIST_HEAD(xen_pcibk_quirks);
static inline const struct pci_device_id *
match_one_device(const struct pci_device_id *id, const struct pci_dev *dev)
{
        if ((id->vendor == PCI_ANY_ID || id->vendor == dev->vendor) &&
            (id->device == PCI_ANY_ID || id->device == dev->device) &&
            (id->subvendor == PCI_ANY_ID ||
                                id->subvendor == dev->subsystem_vendor) &&
            (id->subdevice == PCI_ANY_ID ||
                                id->subdevice == dev->subsystem_device) &&
            !((id->class ^ dev->class) & id->class_mask))
                return id;
        return NULL;
}

static struct xen_pcibk_config_quirk *xen_pcibk_find_quirk(struct pci_dev *dev)
{
        struct xen_pcibk_config_quirk *tmp_quirk;

        list_for_each_entry(tmp_quirk, &xen_pcibk_quirks, quirks_list)
                if (match_one_device(&tmp_quirk->devid, dev) != NULL)
                        goto out;
        tmp_quirk = NULL;
        dev_printk(KERN_DEBUG, &dev->dev,
                   "quirk didn't match any device known\n");
out:
        return tmp_quirk;
}

static inline void register_quirk(struct xen_pcibk_config_quirk *quirk)
{
        list_add_tail(&quirk->quirks_list, &xen_pcibk_quirks);
}

int xen_pcibk_field_is_dup(struct pci_dev *dev, unsigned int reg)
{
        int ret = 0;
        struct xen_pcibk_dev_data *dev_data = pci_get_drvdata(dev);
        struct config_field_entry *cfg_entry;

        list_for_each_entry(cfg_entry, &dev_data->config_fields, list) {
                if (OFFSET(cfg_entry) == reg) {
                        ret = 1;
                        break;
                }
        }
        return ret;
}

int xen_pcibk_config_quirks_add_field(struct pci_dev *dev, struct config_field
                                    *field)
{
        int err = 0;

        switch (field->size) {
        case 1:
                field->u.b.read = xen_pcibk_read_config_byte;
                field->u.b.write = xen_pcibk_write_config_byte;
                break;
        case 2:
                field->u.w.read = xen_pcibk_read_config_word;
                field->u.w.write = xen_pcibk_write_config_word;
                break;
        case 4:
                field->u.dw.read = xen_pcibk_read_config_dword;
                field->u.dw.write = xen_pcibk_write_config_dword;
                break;
        default:
                err = -EINVAL;
                goto out;
        }

        xen_pcibk_config_add_field(dev, field);

out:
        return err;
}

int xen_pcibk_config_quirks_init(struct pci_dev *dev)
{
        struct xen_pcibk_config_quirk *quirk;
        int ret = 0;

        quirk = kzalloc_obj(*quirk);
        if (!quirk) {
                ret = -ENOMEM;
                goto out;
        }

        quirk->devid.vendor = dev->vendor;
        quirk->devid.device = dev->device;
        quirk->devid.subvendor = dev->subsystem_vendor;
        quirk->devid.subdevice = dev->subsystem_device;
        quirk->devid.class = 0;
        quirk->devid.class_mask = 0;
        quirk->devid.driver_data = 0UL;

        quirk->pdev = dev;

        register_quirk(quirk);
out:
        return ret;
}

void xen_pcibk_config_field_free(struct config_field *field)
{
        kfree(field);
}

int xen_pcibk_config_quirk_release(struct pci_dev *dev)
{
        struct xen_pcibk_config_quirk *quirk;
        int ret = 0;

        quirk = xen_pcibk_find_quirk(dev);
        if (!quirk) {
                ret = -ENXIO;
                goto out;
        }

        list_del(&quirk->quirks_list);
        kfree(quirk);

out:
        return ret;
}