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pci.c

/*
 * 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 <asm/io.h>
#include <asm/irq.h>
#include <asm/system.h>
#include <asm/hardware.h>

#include <asm/mach/pci.h>

static 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 callling 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;
}


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