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pci-bcm1480ht.c

/*
 * Copyright (C) 2001,2002,2005 Broadcom Corporation
 * Copyright (C) 2004 by Ralf Baechle (ralf@linux-mips.org)
 *
 * 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.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 */

/*
 * BCM1480/1455-specific HT support (looking like PCI)
 *
 * This module provides the glue between Linux's PCI subsystem
 * and the hardware.  We basically provide glue for accessing
 * configuration space, and set up the translation for I/O
 * space accesses.
 *
 * To access configuration space, we use ioremap.  In the 32-bit
 * kernel, this consumes either 4 or 8 page table pages, and 16MB of
 * kernel mapped memory.  Hopefully neither of these should be a huge
 * problem.
 *
 */
#include <linux/types.h>
#include <linux/pci.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/mm.h>
#include <linux/console.h>
#include <linux/tty.h>

#include <asm/sibyte/bcm1480_regs.h>
#include <asm/sibyte/bcm1480_scd.h>
#include <asm/sibyte/board.h>
#include <asm/io.h>

/*
 * Macros for calculating offsets into config space given a device
 * structure or dev/fun/reg
 */
#define CFGOFFSET(bus, devfn, where) (((bus)<<16)+((devfn)<<8)+(where))
#define CFGADDR(bus, devfn, where)   CFGOFFSET((bus)->number, (devfn), where)

static void *ht_cfg_space;

#define PCI_BUS_ENABLED 1
#define PCI_DEVICE_MODE 2

static int bcm1480ht_bus_status = 0;

#define PCI_BRIDGE_DEVICE  0
#define HT_BRIDGE_DEVICE   1

/*
 * HT's level-sensitive interrupts require EOI, which is generated
 * through a 4MB memory-mapped region
 */
unsigned long ht_eoi_space;

/*
 * Read/write 32-bit values in config space.
 */
static inline u32 READCFG32(u32 addr)
{
      return *(u32 *)(ht_cfg_space + (addr&~3));
}

static inline void WRITECFG32(u32 addr, u32 data)
{
      *(u32 *)(ht_cfg_space + (addr & ~3)) = data;
}

/*
 * Some checks before doing config cycles:
 * In PCI Device Mode, hide everything on bus 0 except the LDT host
 * bridge.  Otherwise, access is controlled by bridge MasterEn bits.
 */
static int bcm1480ht_can_access(struct pci_bus *bus, int devfn)
{
      u32 devno;

      if (!(bcm1480ht_bus_status & (PCI_BUS_ENABLED | PCI_DEVICE_MODE)))
            return 0;

      if (bus->number == 0) {
            devno = PCI_SLOT(devfn);
            if (bcm1480ht_bus_status & PCI_DEVICE_MODE)
                  return 0;
      }
      return 1;
}

/*
 * Read/write access functions for various sizes of values
 * in config space.  Return all 1's for disallowed accesses
 * for a kludgy but adequate simulation of master aborts.
 */

static int bcm1480ht_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 (bcm1480ht_can_access(bus, devfn))
            data = READCFG32(CFGADDR(bus, devfn, where));
      else
            data = 0xFFFFFFFF;

      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 bcm1480ht_pcibios_write(struct pci_bus *bus, unsigned int devfn,
                           int where, int size, u32 val)
{
      u32 cfgaddr = CFGADDR(bus, devfn, where);
      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 (!bcm1480ht_can_access(bus, devfn))
            return PCIBIOS_BAD_REGISTER_NUMBER;

      data = READCFG32(cfgaddr);

      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));
      else
            data = val;

      WRITECFG32(cfgaddr, data);

      return PCIBIOS_SUCCESSFUL;
}

static int bcm1480ht_pcibios_get_busno(void)
{
      return 0;
}

struct pci_ops bcm1480ht_pci_ops = {
      .read = bcm1480ht_pcibios_read,
      .write      = bcm1480ht_pcibios_write,
};

static struct resource bcm1480ht_mem_resource = {
      .name = "BCM1480 HT MEM",
      .start      = 0x40000000UL,
      .end  = 0x5fffffffUL,
      .flags      = IORESOURCE_MEM,
};

static struct resource bcm1480ht_io_resource = {
      .name = "BCM1480 HT I/O",
      .start      = 0x00000000UL,
      .end  = 0x01ffffffUL,
      .flags      = IORESOURCE_IO,
};

struct pci_controller bcm1480ht_controller = {
      .pci_ops    = &bcm1480ht_pci_ops,
      .mem_resource     = &bcm1480ht_mem_resource,
      .io_resource      = &bcm1480ht_io_resource,
      .index            = 1,
      .get_busno  = bcm1480ht_pcibios_get_busno,
};

static int __init bcm1480ht_pcibios_init(void)
{
      uint32_t cmdreg;

      ht_cfg_space = ioremap(A_BCM1480_PHYS_HT_CFG_MATCH_BITS, 16*1024*1024);

      /*
       * See if the PCI bus has been configured by the firmware.
       */
      cmdreg = READCFG32(CFGOFFSET(0, PCI_DEVFN(PCI_BRIDGE_DEVICE, 0),
                             PCI_COMMAND));
      if (!(cmdreg & PCI_COMMAND_MASTER)) {
            printk("HT: Skipping HT probe. Bus is not initialized.\n");
            iounmap(ht_cfg_space);
            return 1; /* XXX */
      }
      bcm1480ht_bus_status |= PCI_BUS_ENABLED;

      ht_eoi_space = (unsigned long)
            ioremap(A_BCM1480_PHYS_HT_SPECIAL_MATCH_BYTES,
                  4 * 1024 * 1024);

      register_pci_controller(&bcm1480ht_controller);

      return 0;
}

arch_initcall(bcm1480ht_pcibios_init);

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