/* ASB2305 PCI support
 *
 * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
 * Written by David Howells (dhowells@redhat.com)
 * Derived from arch/i386/kernel/pci-pc.c
 *      (c) 1999--2000 Martin Mares <mj@suse.cz>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public Licence
 * as published by the Free Software Foundation; either version
 * 2 of the Licence, or (at your option) any later version.
 */
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/pci.h>
#include <linux/init.h>
#include <linux/ioport.h>
#include <linux/delay.h>
#include <linux/irq.h>
#include <asm/io.h>
#include <asm/irq.h>
#include "pci-asb2305.h"

unsigned int pci_probe = 1;

struct pci_ops *pci_root_ops;

/*
 * The accessible PCI window does not cover the entire CPU address space, but
 * there are devices we want to access outside of that window, so we need to
 * insert specific PCI bus resources instead of using the platform-level bus
 * resources directly for the PCI root bus.
 *
 * These are configured and inserted by pcibios_init().
 */
static struct resource pci_ioport_resource = {
        .name   = "PCI IO",
        .start  = 0xbe000000,
        .end    = 0xbe03ffff,
        .flags  = IORESOURCE_IO,
};

static struct resource pci_iomem_resource = {
        .name   = "PCI mem",
        .start  = 0xb8000000,
        .end    = 0xbbffffff,
        .flags  = IORESOURCE_MEM,
};

/*
 * Functions for accessing PCI configuration space
 */

#define CONFIG_CMD(bus, devfn, where) \
        (0x80000000 | (bus->number << 16) | (devfn << 8) | (where & ~3))

#define MEM_PAGING_REG  (*(volatile __u32 *) 0xBFFFFFF4)
#define CONFIG_ADDRESS  (*(volatile __u32 *) 0xBFFFFFF8)
#define CONFIG_DATAL(X) (*(volatile __u32 *) 0xBFFFFFFC)
#define CONFIG_DATAW(X) (*(volatile __u16 *) (0xBFFFFFFC + ((X) & 2)))
#define CONFIG_DATAB(X) (*(volatile __u8  *) (0xBFFFFFFC + ((X) & 3)))

#define BRIDGEREGB(X)   (*(volatile __u8  *) (0xBE040000 + (X)))
#define BRIDGEREGW(X)   (*(volatile __u16 *) (0xBE040000 + (X)))
#define BRIDGEREGL(X)   (*(volatile __u32 *) (0xBE040000 + (X)))

static inline int __query(const struct pci_bus *bus, unsigned int devfn)
{
#if 0
        return bus->number == 0 && (devfn == PCI_DEVFN(0, 0));
        return bus->number == 1;
        return bus->number == 0 &&
                (devfn == PCI_DEVFN(2, 0) || devfn == PCI_DEVFN(3, 0));
#endif
        return 1;
}

/*
 *
 */
static int pci_ampci_read_config_byte(struct pci_bus *bus, unsigned int devfn,
                                      int where, u32 *_value)
{
        u32 rawval, value;

        if (bus->number == 0 && devfn == PCI_DEVFN(0, 0)) {
                value = BRIDGEREGB(where);
                __pcbdebug("=> %02hx", &BRIDGEREGL(where), value);
        } else {
                CONFIG_ADDRESS = CONFIG_CMD(bus, devfn, where);
                rawval = CONFIG_ADDRESS;
                value = CONFIG_DATAB(where);
                if (__query(bus, devfn))
                        __pcidebug("=> %02hx", bus, devfn, where, value);
        }

        *_value = value;
        return PCIBIOS_SUCCESSFUL;
}

static int pci_ampci_read_config_word(struct pci_bus *bus, unsigned int devfn,
                                      int where, u32 *_value)
{
        u32 rawval, value;

        if (bus->number == 0 && devfn == PCI_DEVFN(0, 0)) {
                value = BRIDGEREGW(where);
                __pcbdebug("=> %04hx", &BRIDGEREGL(where), value);
        } else {
                CONFIG_ADDRESS = CONFIG_CMD(bus, devfn, where);
                rawval = CONFIG_ADDRESS;
                value = CONFIG_DATAW(where);
                if (__query(bus, devfn))
                        __pcidebug("=> %04hx", bus, devfn, where, value);
        }

        *_value = value;
        return PCIBIOS_SUCCESSFUL;
}

static int pci_ampci_read_config_dword(struct pci_bus *bus, unsigned int devfn,
                                       int where, u32 *_value)
{
        u32 rawval, value;

        if (bus->number == 0 && devfn == PCI_DEVFN(0, 0)) {
                value = BRIDGEREGL(where);
                __pcbdebug("=> %08x", &BRIDGEREGL(where), value);
        } else {
                CONFIG_ADDRESS = CONFIG_CMD(bus, devfn, where);
                rawval = CONFIG_ADDRESS;
                value = CONFIG_DATAL(where);
                if (__query(bus, devfn))
                        __pcidebug("=> %08x", bus, devfn, where, value);
        }

        *_value = value;
        return PCIBIOS_SUCCESSFUL;
}

static int pci_ampci_write_config_byte(struct pci_bus *bus, unsigned int devfn,
                                       int where, u8 value)
{
        u32 rawval;

        if (bus->number == 0 && devfn == PCI_DEVFN(0, 0)) {
                __pcbdebug("<= %02x", &BRIDGEREGB(where), value);
                BRIDGEREGB(where) = value;
        } else {
                if (bus->number == 0 &&
                    (devfn == PCI_DEVFN(2, 0) || devfn == PCI_DEVFN(3, 0))
                    )
                        __pcidebug("<= %02x", bus, devfn, where, value);
                CONFIG_ADDRESS = CONFIG_CMD(bus, devfn, where);
                rawval = CONFIG_ADDRESS;
                CONFIG_DATAB(where) = value;
        }
        return PCIBIOS_SUCCESSFUL;
}

static int pci_ampci_write_config_word(struct pci_bus *bus, unsigned int devfn,
                                       int where, u16 value)
{
        u32 rawval;

        if (bus->number == 0 && devfn == PCI_DEVFN(0, 0)) {
                __pcbdebug("<= %04hx", &BRIDGEREGW(where), value);
                BRIDGEREGW(where) = value;
        } else {
                if (__query(bus, devfn))
                        __pcidebug("<= %04hx", bus, devfn, where, value);
                CONFIG_ADDRESS = CONFIG_CMD(bus, devfn, where);
                rawval = CONFIG_ADDRESS;
                CONFIG_DATAW(where) = value;
        }
        return PCIBIOS_SUCCESSFUL;
}

static int pci_ampci_write_config_dword(struct pci_bus *bus, unsigned int devfn,
                                        int where, u32 value)
{
        u32 rawval;

        if (bus->number == 0 && devfn == PCI_DEVFN(0, 0)) {
                __pcbdebug("<= %08x", &BRIDGEREGL(where), value);
                BRIDGEREGL(where) = value;
        } else {
                if (__query(bus, devfn))
                        __pcidebug("<= %08x", bus, devfn, where, value);
                CONFIG_ADDRESS = CONFIG_CMD(bus, devfn, where);
                rawval = CONFIG_ADDRESS;
                CONFIG_DATAL(where) = value;
        }
        return PCIBIOS_SUCCESSFUL;
}

static int pci_ampci_read_config(struct pci_bus *bus, unsigned int devfn,
                                 int where, int size, u32 *val)
{
        switch (size) {
        case 1:
                return pci_ampci_read_config_byte(bus, devfn, where, val);
        case 2:
                return pci_ampci_read_config_word(bus, devfn, where, val);
        case 4:
                return pci_ampci_read_config_dword(bus, devfn, where, val);
        default:
                BUG();
                return -EOPNOTSUPP;
        }
}

static int pci_ampci_write_config(struct pci_bus *bus, unsigned int devfn,
                                  int where, int size, u32 val)
{
        switch (size) {
        case 1:
                return pci_ampci_write_config_byte(bus, devfn, where, val);
        case 2:
                return pci_ampci_write_config_word(bus, devfn, where, val);
        case 4:
                return pci_ampci_write_config_dword(bus, devfn, where, val);
        default:
                BUG();
                return -EOPNOTSUPP;
        }
}

static struct pci_ops pci_direct_ampci = {
        .read = pci_ampci_read_config,
        .write = pci_ampci_write_config,
};

/*
 * Before we decide to use direct hardware access mechanisms, we try to do some
 * trivial checks to ensure it at least _seems_ to be working -- we just test
 * whether bus 00 contains a host bridge (this is similar to checking
 * techniques used in XFree86, but ours should be more reliable since we
 * attempt to make use of direct access hints provided by the PCI BIOS).
 *
 * This should be close to trivial, but it isn't, because there are buggy
 * chipsets (yes, you guessed it, by Intel and Compaq) that have no class ID.
 */
static int __init pci_sanity_check(struct pci_ops *o)
{
        struct pci_bus bus;             /* Fake bus and device */
        u32 x;

        bus.number = 0;

        if ((!o->read(&bus, 0, PCI_CLASS_DEVICE, 2, &x) &&
             (x == PCI_CLASS_BRIDGE_HOST || x == PCI_CLASS_DISPLAY_VGA)) ||
            (!o->read(&bus, 0, PCI_VENDOR_ID, 2, &x) &&
             (x == PCI_VENDOR_ID_INTEL || x == PCI_VENDOR_ID_COMPAQ)))
                return 1;

        printk(KERN_ERR "PCI: Sanity check failed\n");
        return 0;
}

static int __init pci_check_direct(void)
{
        unsigned long flags;

        local_irq_save(flags);

        /*
         * Check if access works.
         */
        if (pci_sanity_check(&pci_direct_ampci)) {
                local_irq_restore(flags);
                printk(KERN_INFO "PCI: Using configuration ampci\n");
                request_mem_region(0xBE040000, 256, "AMPCI bridge");
                request_mem_region(0xBFFFFFF4, 12, "PCI ampci");
                request_mem_region(0xBC000000, 32 * 1024 * 1024, "PCI SRAM");
                return 0;
        }

        local_irq_restore(flags);
        return -ENODEV;
}

static void pcibios_fixup_device_resources(struct pci_dev *dev)
{
        int idx;

        if (!dev->bus)
                return;

        for (idx = 0; idx < PCI_BRIDGE_RESOURCES; idx++) {
                struct resource *r = &dev->resource[idx];

                if (!r->flags || r->parent || !r->start)
                        continue;

                pci_claim_resource(dev, idx);
        }
}

static void pcibios_fixup_bridge_resources(struct pci_dev *dev)
{
        int idx;

        if (!dev->bus)
                return;

        for (idx = PCI_BRIDGE_RESOURCES; idx < PCI_NUM_RESOURCES; idx++) {
                struct resource *r = &dev->resource[idx];

                if (!r->flags || r->parent || !r->start)
                        continue;

                pci_claim_bridge_resource(dev, idx);
        }
}

/*
 *  Called after each bus is probed, but before its children
 *  are examined.
 */
void pcibios_fixup_bus(struct pci_bus *bus)
{
        struct pci_dev *dev;

        if (bus->self) {
                pci_read_bridge_bases(bus);
                pcibios_fixup_bridge_resources(bus->self);
        }

        list_for_each_entry(dev, &bus->devices, bus_list)
                pcibios_fixup_device_resources(dev);
}

/*
 * Initialization. Try all known PCI access methods. Note that we support
 * using both PCI BIOS and direct access: in such cases, we use I/O ports
 * to access config space, but we still keep BIOS order of cards to be
 * compatible with 2.0.X. This should go away some day.
 */
static int __init pcibios_init(void)
{
        resource_size_t io_offset, mem_offset;
        LIST_HEAD(resources);
        struct pci_bus *bus;

        ioport_resource.start   = 0xA0000000;
        ioport_resource.end     = 0xDFFFFFFF;
        iomem_resource.start    = 0xA0000000;
        iomem_resource.end      = 0xDFFFFFFF;

        if (insert_resource(&iomem_resource, &pci_iomem_resource) < 0)
                panic("Unable to insert PCI IOMEM resource\n");
        if (insert_resource(&ioport_resource, &pci_ioport_resource) < 0)
                panic("Unable to insert PCI IOPORT resource\n");

        if (!pci_probe)
                return 0;

        if (pci_check_direct() < 0) {
                printk(KERN_WARNING "PCI: No PCI bus detected\n");
                return 0;
        }

        printk(KERN_INFO "PCI: Probing PCI hardware [mempage %08x]\n",
               MEM_PAGING_REG);

        io_offset = pci_ioport_resource.start -
            (pci_ioport_resource.start & 0x00ffffff);
        mem_offset = pci_iomem_resource.start -
            ((pci_iomem_resource.start & 0x03ffffff) | MEM_PAGING_REG);

        pci_add_resource_offset(&resources, &pci_ioport_resource, io_offset);
        pci_add_resource_offset(&resources, &pci_iomem_resource, mem_offset);
        bus = pci_scan_root_bus(NULL, 0, &pci_direct_ampci, NULL, &resources);
        if (!bus)
                return 0;

        pcibios_irq_init();
        pcibios_fixup_irqs();
        pcibios_resource_survey();
        pci_bus_add_devices(bus);
        return 0;
}

arch_initcall(pcibios_init);

char *__init pcibios_setup(char *str)
{
        if (!strcmp(str, "off")) {
                pci_probe = 0;
                return NULL;
        }

        return str;
}

int pcibios_enable_device(struct pci_dev *dev, int mask)
{
        int err;

        err = pci_enable_resources(dev, mask);
        if (err == 0)
                pcibios_enable_irq(dev);
        return err;
}

/*
 * disable the ethernet chipset
 */
static void __init unit_disable_pcnet(struct pci_bus *bus, struct pci_ops *o)
{
        u32 x;

        bus->number = 0;

        o->read (bus, PCI_DEVFN(2, 0), PCI_VENDOR_ID,           4, &x);
        o->read (bus, PCI_DEVFN(2, 0), PCI_COMMAND,             2, &x);
        x |= PCI_COMMAND_MASTER |
                PCI_COMMAND_IO | PCI_COMMAND_MEMORY |
                PCI_COMMAND_SERR | PCI_COMMAND_PARITY;
        o->write(bus, PCI_DEVFN(2, 0), PCI_COMMAND,             2, x);
        o->read (bus, PCI_DEVFN(2, 0), PCI_COMMAND,             2, &x);
        o->write(bus, PCI_DEVFN(2, 0), PCI_BASE_ADDRESS_0,      4, 0x00030001);
        o->read (bus, PCI_DEVFN(2, 0), PCI_BASE_ADDRESS_0,      4, &x);

#define RDP (*(volatile u32 *) 0xBE030010)
#define RAP (*(volatile u32 *) 0xBE030014)
#define __set_RAP(X) do { RAP = (X); x = RAP; } while (0)
#define __set_RDP(X) do { RDP = (X); x = RDP; } while (0)
#define __get_RDP() ({ RDP & 0xffff; })

        __set_RAP(0);
        __set_RDP(0x0004);      /* CSR0 = STOP */

        __set_RAP(88);          /* check CSR88 indicates an Am79C973 */
        BUG_ON(__get_RDP() != 0x5003);

        for (x = 0; x < 100; x++)
                asm volatile("nop");

        __set_RDP(0x0004);      /* CSR0 = STOP */
}

/*
 * initialise the unit hardware
 */
asmlinkage void __init unit_pci_init(void)
{
        struct pci_bus bus;             /* Fake bus and device */
        struct pci_ops *o = &pci_direct_ampci;
        u32 x;

        set_intr_level(XIRQ1, NUM2GxICR_LEVEL(CONFIG_PCI_IRQ_LEVEL));

        memset(&bus, 0, sizeof(bus));

        MEM_PAGING_REG = 0xE8000000;

        /* we need to set up the bridge _now_ or we won't be able to access the
         * PCI config registers
         */
        BRIDGEREGW(PCI_COMMAND) |=
                PCI_COMMAND_SERR | PCI_COMMAND_PARITY |
                PCI_COMMAND_MEMORY | PCI_COMMAND_IO | PCI_COMMAND_MASTER;
        BRIDGEREGW(PCI_STATUS)          = 0xF800;
        BRIDGEREGB(PCI_LATENCY_TIMER)   = 0x10;
        BRIDGEREGL(PCI_BASE_ADDRESS_0)  = 0x80000000;
        BRIDGEREGB(PCI_INTERRUPT_LINE)  = 1;
        BRIDGEREGL(0x48)                = 0x98000000;   /* AMPCI base addr */
        BRIDGEREGB(0x41)                = 0x00;         /* secondary bus
                                                         * number */
        BRIDGEREGB(0x42)                = 0x01;         /* subordinate bus
                                                         * number */
        BRIDGEREGB(0x44)                = 0x01;
        BRIDGEREGL(0x50)                = 0x00000001;
        BRIDGEREGL(0x58)                = 0x00001002;
        BRIDGEREGL(0x5C)                = 0x00000011;

        /* we also need to set up the PCI-PCI bridge */
        bus.number = 0;

        /* IO: 0x00000000-0x00020000 */
        o->read (&bus, PCI_DEVFN(3, 0), PCI_COMMAND,            2, &x);
        x |= PCI_COMMAND_MASTER |
                PCI_COMMAND_IO | PCI_COMMAND_MEMORY |
                PCI_COMMAND_SERR | PCI_COMMAND_PARITY;
        o->write(&bus, PCI_DEVFN(3, 0), PCI_COMMAND,            2, x);

        o->read (&bus, PCI_DEVFN(3, 0), PCI_IO_BASE,            1, &x);
        o->read (&bus, PCI_DEVFN(3, 0), PCI_IO_BASE_UPPER16,    4, &x);
        o->read (&bus, PCI_DEVFN(3, 0), PCI_MEMORY_BASE,        4, &x);
        o->read (&bus, PCI_DEVFN(3, 0), PCI_PREF_MEMORY_BASE,   4, &x);

        o->write(&bus, PCI_DEVFN(3, 0), PCI_IO_BASE,            1, 0x01);
        o->read (&bus, PCI_DEVFN(3, 0), PCI_IO_BASE,            1, &x);
        o->write(&bus, PCI_DEVFN(3, 0), PCI_IO_BASE_UPPER16,    4, 0x00020000);
        o->read (&bus, PCI_DEVFN(3, 0), PCI_IO_BASE_UPPER16,    4, &x);
        o->write(&bus, PCI_DEVFN(3, 0), PCI_MEMORY_BASE,        4, 0xEBB0EA00);
        o->read (&bus, PCI_DEVFN(3, 0), PCI_MEMORY_BASE,        4, &x);
        o->write(&bus, PCI_DEVFN(3, 0), PCI_PREF_MEMORY_BASE,   4, 0xE9F0E800);
        o->read (&bus, PCI_DEVFN(3, 0), PCI_PREF_MEMORY_BASE,   4, &x);

        unit_disable_pcnet(&bus, o);
}