// SPDX-License-Identifier: GPL-2.0
#include <linux/kernel.h>
#include <linux/pci.h>
#include <asm/pci-direct.h>
#include <asm/io.h>
#include <asm/pci_x86.h>

/* Direct PCI access. This is used for PCI accesses in early boot before
   the PCI subsystem works. */

u32 read_pci_config(u8 bus, u8 slot, u8 func, u8 offset)
{
        u32 v;
        outl(0x80000000 | (bus<<16) | (slot<<11) | (func<<8) | offset, 0xcf8);
        v = inl(0xcfc);
        return v;
}

u8 read_pci_config_byte(u8 bus, u8 slot, u8 func, u8 offset)
{
        u8 v;
        outl(0x80000000 | (bus<<16) | (slot<<11) | (func<<8) | offset, 0xcf8);
        v = inb(0xcfc + (offset&3));
        return v;
}

u16 read_pci_config_16(u8 bus, u8 slot, u8 func, u8 offset)
{
        u16 v;
        outl(0x80000000 | (bus<<16) | (slot<<11) | (func<<8) | offset, 0xcf8);
        v = inw(0xcfc + (offset&2));
        return v;
}

void write_pci_config(u8 bus, u8 slot, u8 func, u8 offset,
                                    u32 val)
{
        outl(0x80000000 | (bus<<16) | (slot<<11) | (func<<8) | offset, 0xcf8);
        outl(val, 0xcfc);
}

void write_pci_config_byte(u8 bus, u8 slot, u8 func, u8 offset, u8 val)
{
        outl(0x80000000 | (bus<<16) | (slot<<11) | (func<<8) | offset, 0xcf8);
        outb(val, 0xcfc + (offset&3));
}

void write_pci_config_16(u8 bus, u8 slot, u8 func, u8 offset, u16 val)
{
        outl(0x80000000 | (bus<<16) | (slot<<11) | (func<<8) | offset, 0xcf8);
        outw(val, 0xcfc + (offset&2));
}

int early_pci_allowed(void)
{
        return (pci_probe & (PCI_PROBE_CONF1|PCI_PROBE_NOEARLY)) ==
                        PCI_PROBE_CONF1;
}