/*
 * arch/arm/mach-ixp2000/pci.c
 *
 * PCI routines for IXDP2400/IXDP2800 boards
 *
 * Original Author: Naeem Afzal <naeem.m.afzal@intel.com>
 * Maintained by: Deepak Saxena <dsaxena@plexity.net>
 *
 * Copyright 2002 Intel Corp.
 * Copyright (C) 2003-2004 MontaVista Software, Inc.
 *
 *  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/sched.h>
#include <linux/kernel.h>
#include <linux/pci.h>
#include <linux/interrupt.h>
#include <linux/mm.h>
#include <linux/init.h>
#include <linux/ioport.h>
#include <linux/slab.h>
#include <linux/delay.h>
#include <linux/io.h>

#include <asm/irq.h>
#include <asm/system.h>
#include <mach/hardware.h>

#include <asm/mach/pci.h>

static volatile int pci_master_aborts = 0;

static int clear_master_aborts(void);

u32 *
ixp2000_pci_config_addr(unsigned int bus_nr, unsigned int devfn, int where)
{
        u32 *paddress;

        if (PCI_SLOT(devfn) > 7)
                return 0;

        /* Must be dword aligned */
        where &= ~3;

        /*
         * For top bus, generate type 0, else type 1
         */
        if (!bus_nr) {
                /* only bits[23:16] are used for IDSEL */
                paddress = (u32 *) (IXP2000_PCI_CFG0_VIRT_BASE
                                    | (1 << (PCI_SLOT(devfn) + 16))
                                    | (PCI_FUNC(devfn) << 8) | where);
        } else {
                paddress = (u32 *) (IXP2000_PCI_CFG1_VIRT_BASE 
                                    | (bus_nr << 16)
                                    | (PCI_SLOT(devfn) << 11)
                                    | (PCI_FUNC(devfn) << 8) | where);
        }

        return paddress;
}

/*
 * Mask table, bits to mask for quantity of size 1, 2 or 4 bytes.
 * 0 and 3 are not valid indexes...
 */
static u32 bytemask[] = {
        /*0*/   0,
        /*1*/   0xff,
        /*2*/   0xffff,
        /*3*/   0,
        /*4*/   0xffffffff,
};


int ixp2000_pci_read_config(struct pci_bus *bus, unsigned int devfn, int where,
                                int size, u32 *value)
{
        u32 n;
        u32 *addr;

        n = where % 4;

        addr = ixp2000_pci_config_addr(bus->number, devfn, where);
        if (!addr)
                return PCIBIOS_DEVICE_NOT_FOUND;

        pci_master_aborts = 0;
        *value = (*addr >> (8*n)) & bytemask[size];
        if (pci_master_aborts) {
                pci_master_aborts = 0;
                *value = 0xffffffff;
                return PCIBIOS_DEVICE_NOT_FOUND;
        }

        return PCIBIOS_SUCCESSFUL;
}

/*
 * We don't do error checks by calling clear_master_aborts() b/c the
 * assumption is that the caller did a read first to make sure a device
 * exists.
 */
int ixp2000_pci_write_config(struct pci_bus *bus, unsigned int devfn, int where,
                                int size, u32 value)
{
        u32 mask;
        u32 *addr;
        u32 temp;

        mask = ~(bytemask[size] << ((where % 0x4) * 8));
        addr = ixp2000_pci_config_addr(bus->number, devfn, where);
        if (!addr)
                return PCIBIOS_DEVICE_NOT_FOUND;
        temp = (u32) (value) << ((where % 0x4) * 8);
        *addr = (*addr & mask) | temp;

        clear_master_aborts();

        return PCIBIOS_SUCCESSFUL;
}


static struct pci_ops ixp2000_pci_ops = {
        .read   = ixp2000_pci_read_config,
        .write  = ixp2000_pci_write_config
};

struct pci_bus *ixp2000_pci_scan_bus(int nr, struct pci_sys_data *sysdata)
{
        return pci_scan_bus(sysdata->busnr, &ixp2000_pci_ops, sysdata);
}


int ixp2000_pci_abort_handler(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
{

        volatile u32 temp;
        unsigned long flags;

        pci_master_aborts = 1;

        local_irq_save(flags);
        temp = *(IXP2000_PCI_CONTROL);
        if (temp & ((1 << 8) | (1 << 5))) {
                ixp2000_reg_wrb(IXP2000_PCI_CONTROL, temp);
        }

        temp = *(IXP2000_PCI_CMDSTAT);
        if (temp & (1 << 29)) {
                while (temp & (1 << 29)) {      
                        ixp2000_reg_write(IXP2000_PCI_CMDSTAT, temp);
                        temp = *(IXP2000_PCI_CMDSTAT);
                }
        }
        local_irq_restore(flags);

        /*
         * If it was an imprecise abort, then we need to correct the
         * return address to be _after_ the instruction.
         */
        if (fsr & (1 << 10))
                regs->ARM_pc += 4;

        return 0;
}

int
clear_master_aborts(void)
{
        volatile u32 temp;
        unsigned long flags;

        local_irq_save(flags);
        temp = *(IXP2000_PCI_CONTROL);
        if (temp & ((1 << 8) | (1 << 5))) {
                ixp2000_reg_wrb(IXP2000_PCI_CONTROL, temp);
        }

        temp = *(IXP2000_PCI_CMDSTAT);
        if (temp & (1 << 29)) {
                while (temp & (1 << 29)) {
                        ixp2000_reg_write(IXP2000_PCI_CMDSTAT, temp);
                        temp = *(IXP2000_PCI_CMDSTAT);
                }
        }
        local_irq_restore(flags);

        return 0;
}

void __init
ixp2000_pci_preinit(void)
{
#ifndef CONFIG_IXP2000_SUPPORT_BROKEN_PCI_IO
        /*
         * Configure the PCI unit to properly byteswap I/O transactions,
         * and verify that it worked.
         */
        ixp2000_reg_write(IXP2000_PCI_CONTROL,
                          (*IXP2000_PCI_CONTROL | PCI_CONTROL_IEE));

        if ((*IXP2000_PCI_CONTROL & PCI_CONTROL_IEE) == 0)
                panic("IXP2000: PCI I/O is broken on this ixp model, and "
                        "the needed workaround has not been configured in");
#endif

        hook_fault_code(16+6, ixp2000_pci_abort_handler, SIGBUS,
                                "PCI config cycle to non-existent device");
}


/*
 * IXP2000 systems often have large resource requirements, so we just
 * use our own resource space.
 */
static struct resource ixp2000_pci_mem_space = {
        .start  = 0xe0000000,
        .end    = 0xffffffff,
        .flags  = IORESOURCE_MEM,
        .name   = "PCI Mem Space"
};

static struct resource ixp2000_pci_io_space = {
        .start  = 0x00010000,
        .end    = 0x0001ffff,
        .flags  = IORESOURCE_IO,
        .name   = "PCI I/O Space"
};

int ixp2000_pci_setup(int nr, struct pci_sys_data *sys)
{
        if (nr >= 1)
                return 0;

        sys->resource[0] = &ixp2000_pci_io_space;
        sys->resource[1] = &ixp2000_pci_mem_space;
        sys->resource[2] = NULL;

        return 1;
}