/*
 * PowerNV LPC bus handling.
 *
 * Copyright 2013 IBM Corp.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version
 * 2 of the License, or (at your option) any later version.
 */

#include <linux/kernel.h>
#include <linux/of.h>
#include <linux/bug.h>

#include <asm/machdep.h>
#include <asm/firmware.h>
#include <asm/xics.h>
#include <asm/opal.h>

static int opal_lpc_chip_id = -1;

static u8 opal_lpc_inb(unsigned long port)
{
        int64_t rc;
        uint32_t data;

        if (opal_lpc_chip_id < 0 || port > 0xffff)
                return 0xff;
        rc = opal_lpc_read(opal_lpc_chip_id, OPAL_LPC_IO, port, &data, 1);
        return rc ? 0xff : data;
}

static __le16 __opal_lpc_inw(unsigned long port)
{
        int64_t rc;
        uint32_t data;

        if (opal_lpc_chip_id < 0 || port > 0xfffe)
                return 0xffff;
        if (port & 1)
                return (__le16)opal_lpc_inb(port) << 8 | opal_lpc_inb(port + 1);
        rc = opal_lpc_read(opal_lpc_chip_id, OPAL_LPC_IO, port, &data, 2);
        return rc ? 0xffff : data;
}
static u16 opal_lpc_inw(unsigned long port)
{
        return le16_to_cpu(__opal_lpc_inw(port));
}

static __le32 __opal_lpc_inl(unsigned long port)
{
        int64_t rc;
        uint32_t data;

        if (opal_lpc_chip_id < 0 || port > 0xfffc)
                return 0xffffffff;
        if (port & 3)
                return (__le32)opal_lpc_inb(port    ) << 24 |
                       (__le32)opal_lpc_inb(port + 1) << 16 |
                       (__le32)opal_lpc_inb(port + 2) <<  8 |
                               opal_lpc_inb(port + 3);
        rc = opal_lpc_read(opal_lpc_chip_id, OPAL_LPC_IO, port, &data, 4);
        return rc ? 0xffffffff : data;
}

static u32 opal_lpc_inl(unsigned long port)
{
        return le32_to_cpu(__opal_lpc_inl(port));
}

static void opal_lpc_outb(u8 val, unsigned long port)
{
        if (opal_lpc_chip_id < 0 || port > 0xffff)
                return;
        opal_lpc_write(opal_lpc_chip_id, OPAL_LPC_IO, port, val, 1);
}

static void __opal_lpc_outw(__le16 val, unsigned long port)
{
        if (opal_lpc_chip_id < 0 || port > 0xfffe)
                return;
        if (port & 1) {
                opal_lpc_outb(val >> 8, port);
                opal_lpc_outb(val     , port + 1);
                return;
        }
        opal_lpc_write(opal_lpc_chip_id, OPAL_LPC_IO, port, val, 2);
}

static void opal_lpc_outw(u16 val, unsigned long port)
{
        __opal_lpc_outw(cpu_to_le16(val), port);
}

static void __opal_lpc_outl(__le32 val, unsigned long port)
{
        if (opal_lpc_chip_id < 0 || port > 0xfffc)
                return;
        if (port & 3) {
                opal_lpc_outb(val >> 24, port);
                opal_lpc_outb(val >> 16, port + 1);
                opal_lpc_outb(val >>  8, port + 2);
                opal_lpc_outb(val      , port + 3);
                return;
        }
        opal_lpc_write(opal_lpc_chip_id, OPAL_LPC_IO, port, val, 4);
}

static void opal_lpc_outl(u32 val, unsigned long port)
{
        __opal_lpc_outl(cpu_to_le32(val), port);
}

static void opal_lpc_insb(unsigned long p, void *b, unsigned long c)
{
        u8 *ptr = b;

        while(c--)
                *(ptr++) = opal_lpc_inb(p);
}

static void opal_lpc_insw(unsigned long p, void *b, unsigned long c)
{
        __le16 *ptr = b;

        while(c--)
                *(ptr++) = __opal_lpc_inw(p);
}

static void opal_lpc_insl(unsigned long p, void *b, unsigned long c)
{
        __le32 *ptr = b;

        while(c--)
                *(ptr++) = __opal_lpc_inl(p);
}

static void opal_lpc_outsb(unsigned long p, const void *b, unsigned long c)
{
        const u8 *ptr = b;

        while(c--)
                opal_lpc_outb(*(ptr++), p);
}

static void opal_lpc_outsw(unsigned long p, const void *b, unsigned long c)
{
        const __le16 *ptr = b;

        while(c--)
                __opal_lpc_outw(*(ptr++), p);
}

static void opal_lpc_outsl(unsigned long p, const void *b, unsigned long c)
{
        const __le32 *ptr = b;

        while(c--)
                __opal_lpc_outl(*(ptr++), p);
}

static const struct ppc_pci_io opal_lpc_io = {
        .inb    = opal_lpc_inb,
        .inw    = opal_lpc_inw,
        .inl    = opal_lpc_inl,
        .outb   = opal_lpc_outb,
        .outw   = opal_lpc_outw,
        .outl   = opal_lpc_outl,
        .insb   = opal_lpc_insb,
        .insw   = opal_lpc_insw,
        .insl   = opal_lpc_insl,
        .outsb  = opal_lpc_outsb,
        .outsw  = opal_lpc_outsw,
        .outsl  = opal_lpc_outsl,
};

void opal_lpc_init(void)
{
        struct device_node *np;

        /*
         * Look for a Power8 LPC bus tagged as "primary",
         * we currently support only one though the OPAL APIs
         * support any number.
         */
        for_each_compatible_node(np, NULL, "ibm,power8-lpc") {
                if (!of_device_is_available(np))
                        continue;
                if (!of_get_property(np, "primary", NULL))
                        continue;
                opal_lpc_chip_id = of_get_ibm_chip_id(np);
                break;
        }
        if (opal_lpc_chip_id < 0)
                return;

        /* Setup special IO ops */
        ppc_pci_io = opal_lpc_io;
        isa_io_special = true;

        pr_info("OPAL: Power8 LPC bus found, chip ID %d\n", opal_lpc_chip_id);
}