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ops-au1000.c

/*
 * BRIEF MODULE DESCRIPTION
 *    Alchemy/AMD Au1xx0 PCI support.
 *
 * Copyright 2001-2003, 2007-2008 MontaVista Software Inc.
 * Author: MontaVista Software, Inc. <source@mvista.com>
 *
 *  Support for all devices (greater than 16) added by David Gathright.
 *
 *  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  SOFTWARE  IS PROVIDED   ``AS  IS'' AND   ANY  EXPRESS OR IMPLIED
 *  WARRANTIES,   INCLUDING, BUT NOT  LIMITED  TO, THE IMPLIED WARRANTIES OF
 *  MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN
 *  NO  EVENT  SHALL   THE AUTHOR  BE    LIABLE FOR ANY   DIRECT, INDIRECT,
 *  INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 *  NOT LIMITED   TO, PROCUREMENT OF  SUBSTITUTE GOODS  OR SERVICES; LOSS OF
 *  USE, DATA,  OR PROFITS; OR  BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
 *  ANY THEORY OF LIABILITY, WHETHER IN  CONTRACT, STRICT LIABILITY, OR TORT
 *  (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 *  THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 *  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.,
 *  675 Mass Ave, Cambridge, MA 02139, USA.
 */

#include <linux/types.h>
#include <linux/pci.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/vmalloc.h>

#include <asm/mach-au1x00/au1000.h>

#undef      DEBUG
#ifdef      DEBUG
#define DBG(x...) printk(KERN_DEBUG x)
#else
#define DBG(x...)
#endif

#define PCI_ACCESS_READ  0
#define PCI_ACCESS_WRITE 1

int (*board_pci_idsel)(unsigned int devsel, int assert);

void mod_wired_entry(int entry, unsigned long entrylo0,
            unsigned long entrylo1, unsigned long entryhi,
            unsigned long pagemask)
{
      unsigned long old_pagemask;
      unsigned long old_ctx;

      /* Save old context and create impossible VPN2 value */
      old_ctx = read_c0_entryhi() & 0xff;
      old_pagemask = read_c0_pagemask();
      write_c0_index(entry);
      write_c0_pagemask(pagemask);
      write_c0_entryhi(entryhi);
      write_c0_entrylo0(entrylo0);
      write_c0_entrylo1(entrylo1);
      tlb_write_indexed();
      write_c0_entryhi(old_ctx);
      write_c0_pagemask(old_pagemask);
}

static struct vm_struct *pci_cfg_vm;
static int pci_cfg_wired_entry;
static unsigned long last_entryLo0, last_entryLo1;

/*
 * We can't ioremap the entire pci config space because it's too large.
 * Nor can we call ioremap dynamically because some device drivers use
 * the PCI config routines from within interrupt handlers and that
 * becomes a problem in get_vm_area().  We use one wired TLB to handle
 * all config accesses for all busses.
 */
void __init au1x_pci_cfg_init(void)
{
      /* Reserve a wired entry for PCI config accesses */
      pci_cfg_vm = get_vm_area(0x2000, VM_IOREMAP);
      if (!pci_cfg_vm)
            panic(KERN_ERR "PCI unable to get vm area\n");
      pci_cfg_wired_entry = read_c0_wired();
      add_wired_entry(0, 0, (unsigned long)pci_cfg_vm->addr, PM_4K);
      last_entryLo0 = last_entryLo1 = 0xffffffff;
}

static int config_access(unsigned char access_type, struct pci_bus *bus,
                   unsigned int dev_fn, unsigned char where, u32 *data)
{
#if defined(CONFIG_SOC_AU1500) || defined(CONFIG_SOC_AU1550)
      unsigned int device = PCI_SLOT(dev_fn);
      unsigned int function = PCI_FUNC(dev_fn);
      unsigned long offset, status;
      unsigned long cfg_base;
      unsigned long flags;
      int error = PCIBIOS_SUCCESSFUL;
      unsigned long entryLo0, entryLo1;

      if (device > 19) {
            *data = 0xffffffff;
            return -1;
      }

      local_irq_save(flags);
      au_writel(((0x2000 << 16) | (au_readl(Au1500_PCI_STATCMD) & 0xffff)),
                  Au1500_PCI_STATCMD);
      au_sync_udelay(1);

      /*
       * Allow board vendors to implement their own off-chip IDSEL.
       * If it doesn't succeed, may as well bail out at this point.
       */
      if (board_pci_idsel && board_pci_idsel(device, 1) == 0) {
            *data = 0xffffffff;
            local_irq_restore(flags);
            return -1;
      }

      /* Setup the config window */
      if (bus->number == 0)
            cfg_base = (1 << device) << 11;
      else
            cfg_base = 0x80000000 | (bus->number << 16) | (device << 11);

      /* Setup the lower bits of the 36-bit address */
      offset = (function << 8) | (where & ~0x3);
      /* Pick up any address that falls below the page mask */
      offset |= cfg_base & ~PAGE_MASK;

      /* Page boundary */
      cfg_base = cfg_base & PAGE_MASK;

      /*
       * To improve performance, if the current device is the same as
       * the last device accessed, we don't touch the TLB.
       */
      entryLo0 = (6 << 26) | (cfg_base >> 6) | (2 << 3) | 7;
      entryLo1 = (6 << 26) | (cfg_base >> 6) | (0x1000 >> 6) | (2 << 3) | 7;
      if ((entryLo0 != last_entryLo0) || (entryLo1 != last_entryLo1)) {
            mod_wired_entry(pci_cfg_wired_entry, entryLo0, entryLo1,
                        (unsigned long)pci_cfg_vm->addr, PM_4K);
            last_entryLo0 = entryLo0;
            last_entryLo1 = entryLo1;
      }

      if (access_type == PCI_ACCESS_WRITE)
            au_writel(*data, (int)(pci_cfg_vm->addr + offset));
      else
            *data = au_readl((int)(pci_cfg_vm->addr + offset));

      au_sync_udelay(2);

      DBG("cfg_access %d bus->number %u dev %u at %x *data %x conf %lx\n",
          access_type, bus->number, device, where, *data, offset);

      /* Check master abort */
      status = au_readl(Au1500_PCI_STATCMD);

      if (status & (1 << 29)) {
            *data = 0xffffffff;
            error = -1;
            DBG("Au1x Master Abort\n");
      } else if ((status >> 28) & 0xf) {
            DBG("PCI ERR detected: device %u, status %lx\n",
                device, (status >> 28) & 0xf);

            /* Clear errors */
            au_writel(status & 0xf000ffff, Au1500_PCI_STATCMD);

            *data = 0xffffffff;
            error = -1;
      }

      /* Take away the IDSEL. */
      if (board_pci_idsel)
            (void)board_pci_idsel(device, 0);

      local_irq_restore(flags);
      return error;
#endif
}

static int read_config_byte(struct pci_bus *bus, unsigned int devfn,
                      int where,    u8 *val)
{
      u32 data;
      int ret;

      ret = config_access(PCI_ACCESS_READ, bus, devfn, where, &data);
      if (where & 1)
            data >>= 8;
      if (where & 2)
            data >>= 16;
      *val = data & 0xff;
      return ret;
}

static int read_config_word(struct pci_bus *bus, unsigned int devfn,
                      int where, u16 *val)
{
      u32 data;
      int ret;

      ret = config_access(PCI_ACCESS_READ, bus, devfn, where, &data);
      if (where & 2)
            data >>= 16;
      *val = data & 0xffff;
      return ret;
}

static int read_config_dword(struct pci_bus *bus, unsigned int devfn,
                       int where, u32 *val)
{
      int ret;

      ret = config_access(PCI_ACCESS_READ, bus, devfn, where, val);
      return ret;
}

static int write_config_byte(struct pci_bus *bus, unsigned int devfn,
                       int where, u8 val)
{
      u32 data = 0;

      if (config_access(PCI_ACCESS_READ, bus, devfn, where, &data))
            return -1;

      data = (data & ~(0xff << ((where & 3) << 3))) |
             (val << ((where & 3) << 3));

      if (config_access(PCI_ACCESS_WRITE, bus, devfn, where, &data))
            return -1;

      return PCIBIOS_SUCCESSFUL;
}

static int write_config_word(struct pci_bus *bus, unsigned int devfn,
                       int where, u16 val)
{
      u32 data = 0;

      if (config_access(PCI_ACCESS_READ, bus, devfn, where, &data))
            return -1;

      data = (data & ~(0xffff << ((where & 3) << 3))) |
             (val << ((where & 3) << 3));

      if (config_access(PCI_ACCESS_WRITE, bus, devfn, where, &data))
            return -1;

      return PCIBIOS_SUCCESSFUL;
}

static int write_config_dword(struct pci_bus *bus, unsigned int devfn,
                        int where, u32 val)
{
      if (config_access(PCI_ACCESS_WRITE, bus, devfn, where, &val))
            return -1;

      return PCIBIOS_SUCCESSFUL;
}

static int config_read(struct pci_bus *bus, unsigned int devfn,
                   int where, int size, u32 *val)
{
      switch (size) {
      case 1: {
                  u8 _val;
                  int rc = read_config_byte(bus, devfn, where, &_val);

                  *val = _val;
                  return rc;
            }
      case 2: {
                  u16 _val;
                  int rc = read_config_word(bus, devfn, where, &_val);

                  *val = _val;
                  return rc;
            }
      default:
            return read_config_dword(bus, devfn, where, val);
      }
}

static int config_write(struct pci_bus *bus, unsigned int devfn,
                  int where, int size, u32 val)
{
      switch (size) {
      case 1:
            return write_config_byte(bus, devfn, where, (u8) val);
      case 2:
            return write_config_word(bus, devfn, where, (u16) val);
      default:
            return write_config_dword(bus, devfn, where, val);
      }
}

struct pci_ops au1x_pci_ops = {
      config_read,
      config_write
};

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