// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (C) 1999, 2000, 2004  MIPS Technologies, Inc.
 *      All rights reserved.
 *      Authors: Carsten Langgaard <carstenl@mips.com>
 *               Maciej W. Rozycki <macro@mips.com>
 *
 * Copyright (C) 2009 Lemote Inc.
 * Author: Wu Zhangjin <wuzhangjin@gmail.com>
 */
#include <linux/types.h>
#include <linux/pci.h>
#include <linux/kernel.h>
#include <linux/export.h>

#include <loongson.h>

#ifdef CONFIG_CS5536
#include <cs5536/cs5536_pci.h>
#include <cs5536/cs5536.h>
#endif

#define PCI_ACCESS_READ  0
#define PCI_ACCESS_WRITE 1

#define CFG_SPACE_REG(offset) \
        (void *)CKSEG1ADDR(LOONGSON_PCICFG_BASE | (offset))
#define ID_SEL_BEGIN 11
#define MAX_DEV_NUM (31 - ID_SEL_BEGIN)


static int loongson_pcibios_config_access(unsigned char access_type,
                                      struct pci_bus *bus,
                                      unsigned int devfn, int where,
                                      u32 *data)
{
        u32 busnum = bus->number;
        u32 addr, type;
        u32 dummy;
        void *addrp;
        int device = PCI_SLOT(devfn);
        int function = PCI_FUNC(devfn);
        int reg = where & ~3;

        if (busnum == 0) {
                /* board-specific part,currently,only fuloong2f,yeeloong2f
                 * use CS5536, fuloong2e use via686b, gdium has no
                 * south bridge
                 */
#ifdef CONFIG_CS5536
                /* cs5536_pci_conf_read4/write4() will call _rdmsr/_wrmsr() to
                 * access the regsters PCI_MSR_ADDR, PCI_MSR_DATA_LO,
                 * PCI_MSR_DATA_HI, which is bigger than PCI_MSR_CTRL, so, it
                 * will not go this branch, but the others. so, no calling dead
                 * loop here.
                 */
                if ((PCI_IDSEL_CS5536 == device) && (reg < PCI_MSR_CTRL)) {
                        switch (access_type) {
                        case PCI_ACCESS_READ:
                                *data = cs5536_pci_conf_read4(function, reg);
                                break;
                        case PCI_ACCESS_WRITE:
                                cs5536_pci_conf_write4(function, reg, *data);
                                break;
                        }
                        return 0;
                }
#endif
                /* Type 0 configuration for onboard PCI bus */
                if (device > MAX_DEV_NUM)
                        return -1;

                addr = (1 << (device + ID_SEL_BEGIN)) | (function << 8) | reg;
                type = 0;
        } else {
                /* Type 1 configuration for offboard PCI bus */
                addr = (busnum << 16) | (device << 11) | (function << 8) | reg;
                type = 0x10000;
        }

        /* Clear aborts */
        LOONGSON_PCICMD |= LOONGSON_PCICMD_MABORT_CLR | \
                                LOONGSON_PCICMD_MTABORT_CLR;

        LOONGSON_PCIMAP_CFG = (addr >> 16) | type;

        /* Flush Bonito register block */
        dummy = LOONGSON_PCIMAP_CFG;
        mmiowb();

        addrp = CFG_SPACE_REG(addr & 0xffff);
        if (access_type == PCI_ACCESS_WRITE)
                writel(cpu_to_le32(*data), addrp);
        else
                *data = le32_to_cpu(readl(addrp));

        /* Detect Master/Target abort */
        if (LOONGSON_PCICMD & (LOONGSON_PCICMD_MABORT_CLR |
                             LOONGSON_PCICMD_MTABORT_CLR)) {
                /* Error occurred */

                /* Clear bits */
                LOONGSON_PCICMD |= (LOONGSON_PCICMD_MABORT_CLR |
                                  LOONGSON_PCICMD_MTABORT_CLR);

                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 loongson_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 (loongson_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 loongson_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 (loongson_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 (loongson_pcibios_config_access(PCI_ACCESS_WRITE, bus, devfn, where,
                                       &data))
                return -1;

        return PCIBIOS_SUCCESSFUL;
}

struct pci_ops loongson_pci_ops = {
        .read = loongson_pcibios_read,
        .write = loongson_pcibios_write
};

#ifdef CONFIG_CS5536
DEFINE_RAW_SPINLOCK(msr_lock);

void _rdmsr(u32 msr, u32 *hi, u32 *lo)
{
        struct pci_bus bus = {
                .number = PCI_BUS_CS5536
        };
        u32 devfn = PCI_DEVFN(PCI_IDSEL_CS5536, 0);
        unsigned long flags;

        raw_spin_lock_irqsave(&msr_lock, flags);
        loongson_pcibios_write(&bus, devfn, PCI_MSR_ADDR, 4, msr);
        loongson_pcibios_read(&bus, devfn, PCI_MSR_DATA_LO, 4, lo);
        loongson_pcibios_read(&bus, devfn, PCI_MSR_DATA_HI, 4, hi);
        raw_spin_unlock_irqrestore(&msr_lock, flags);
}
EXPORT_SYMBOL(_rdmsr);

void _wrmsr(u32 msr, u32 hi, u32 lo)
{
        struct pci_bus bus = {
                .number = PCI_BUS_CS5536
        };
        u32 devfn = PCI_DEVFN(PCI_IDSEL_CS5536, 0);
        unsigned long flags;

        raw_spin_lock_irqsave(&msr_lock, flags);
        loongson_pcibios_write(&bus, devfn, PCI_MSR_ADDR, 4, msr);
        loongson_pcibios_write(&bus, devfn, PCI_MSR_DATA_LO, 4, lo);
        loongson_pcibios_write(&bus, devfn, PCI_MSR_DATA_HI, 4, hi);
        raw_spin_unlock_irqrestore(&msr_lock, flags);
}
EXPORT_SYMBOL(_wrmsr);
#endif