// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (C) 1999, 2000, 2004, 2005  MIPS Technologies, Inc.
 *    All rights reserved.
 *    Authors: Carsten Langgaard <carstenl@mips.com>
 *             Maciej W. Rozycki <macro@mips.com>
 * Copyright (C) 2005 Ralf Baechle (ralf@linux-mips.org)
 *
 * MIPS boards specific PCI support.
 */
#include <linux/types.h>
#include <linux/pci.h>
#include <linux/kernel.h>

#include <asm/mips-boards/msc01_pci.h>

#define PCI_ACCESS_READ  0
#define PCI_ACCESS_WRITE 1

/*
 *  PCI configuration cycle AD bus definition
 */
/* Type 0 */
#define PCI_CFG_TYPE0_REG_SHF           0
#define PCI_CFG_TYPE0_FUNC_SHF          8

/* Type 1 */
#define PCI_CFG_TYPE1_REG_SHF           0
#define PCI_CFG_TYPE1_FUNC_SHF          8
#define PCI_CFG_TYPE1_DEV_SHF           11
#define PCI_CFG_TYPE1_BUS_SHF           16

static int msc_pcibios_config_access(unsigned char access_type,
        struct pci_bus *bus, unsigned int devfn, int where, u32 * data)
{
        unsigned char busnum = bus->number;
        u32 intr;

        /* Clear status register bits. */
        MSC_WRITE(MSC01_PCI_INTSTAT,
                  (MSC01_PCI_INTCFG_MA_BIT | MSC01_PCI_INTCFG_TA_BIT));

        MSC_WRITE(MSC01_PCI_CFGADDR,
                  ((busnum << MSC01_PCI_CFGADDR_BNUM_SHF) |
                   (PCI_SLOT(devfn) << MSC01_PCI_CFGADDR_DNUM_SHF) |
                   (PCI_FUNC(devfn) << MSC01_PCI_CFGADDR_FNUM_SHF) |
                   ((where / 4) << MSC01_PCI_CFGADDR_RNUM_SHF)));

        /* Perform access */
        if (access_type == PCI_ACCESS_WRITE)
                MSC_WRITE(MSC01_PCI_CFGDATA, *data);
        else
                MSC_READ(MSC01_PCI_CFGDATA, *data);

        /* Detect Master/Target abort */
        MSC_READ(MSC01_PCI_INTSTAT, intr);
        if (intr & (MSC01_PCI_INTCFG_MA_BIT | MSC01_PCI_INTCFG_TA_BIT)) {
                /* Error occurred */

                /* Clear bits */
                MSC_WRITE(MSC01_PCI_INTSTAT,
                          (MSC01_PCI_INTCFG_MA_BIT | MSC01_PCI_INTCFG_TA_BIT));

                return -1;
        }

        return 0;
}


/*
 * We can't address 8 and 16 bit words directly.  Instead we have to
 * read/write a 32bit word and mask/modify the data we actually want.
 */
static int msc_pcibios_read(struct pci_bus *bus, unsigned int devfn,
                             int where, int size, u32 * val)
{
        u32 data = 0;

        if ((size == 2) && (where & 1))
                return PCIBIOS_BAD_REGISTER_NUMBER;
        else if ((size == 4) && (where & 3))
                return PCIBIOS_BAD_REGISTER_NUMBER;

        if (msc_pcibios_config_access(PCI_ACCESS_READ, bus, devfn, where,
                                      &data))
                return -1;

        if (size == 1)
                *val = (data >> ((where & 3) << 3)) & 0xff;
        else if (size == 2)
                *val = (data >> ((where & 3) << 3)) & 0xffff;
        else
                *val = data;

        return PCIBIOS_SUCCESSFUL;
}

static int msc_pcibios_write(struct pci_bus *bus, unsigned int devfn,
                              int where, int size, u32 val)
{
        u32 data = 0;

        if ((size == 2) && (where & 1))
                return PCIBIOS_BAD_REGISTER_NUMBER;
        else if ((size == 4) && (where & 3))
                return PCIBIOS_BAD_REGISTER_NUMBER;

        if (size == 4)
                data = val;
        else {
                if (msc_pcibios_config_access(PCI_ACCESS_READ, bus, devfn,
                                              where, &data))
                        return -1;

                if (size == 1)
                        data = (data & ~(0xff << ((where & 3) << 3))) |
                                (val << ((where & 3) << 3));
                else if (size == 2)
                        data = (data & ~(0xffff << ((where & 3) << 3))) |
                                (val << ((where & 3) << 3));
        }

        if (msc_pcibios_config_access(PCI_ACCESS_WRITE, bus, devfn, where,
                                       &data))
                return -1;

        return PCIBIOS_SUCCESSFUL;
}

struct pci_ops msc_pci_ops = {
        .read = msc_pcibios_read,
        .write = msc_pcibios_write
};