LXR linux/arch/sh/drivers/pci/ops-dreamcast.c

   1/*
   2 * PCI operations for the Sega Dreamcast
   3 *
   4 * Copyright (C) 2001, 2002  M. R. Brown
   5 * Copyright (C) 2002, 2003  Paul Mundt
   6 *
   7 * This file is subject to the terms and conditions of the GNU General Public
   8 * License.  See the file "COPYING" in the main directory of this archive
   9 * for more details.
  10 */
  11
  12#include <linux/sched.h>
  13#include <linux/kernel.h>
  14#include <linux/param.h>
  15#include <linux/interrupt.h>
  16#include <linux/init.h>
  17#include <linux/irq.h>
  18#include <linux/pci.h>
  19#include <linux/module.h>
  20#include <linux/io.h>
  21#include <mach/pci.h>
  22
  23/*
  24 * The !gapspci_config_access case really shouldn't happen, ever, unless
  25 * someone implicitly messes around with the last devfn value.. otherwise we
  26 * only support a single device anyways, and if we didn't have a BBA, we
  27 * wouldn't make it terribly far through the PCI setup anyways.
  28 *
  29 * Also, we could very easily support both Type 0 and Type 1 configurations
  30 * here, but since it doesn't seem that there is any such implementation in
  31 * existence, we don't bother.
  32 *
  33 * I suppose if someone actually gets around to ripping the chip out of
  34 * the BBA and hanging some more devices off of it, then this might be
  35 * something to take into consideration. However, due to the cost of the BBA,
  36 * and the general lack of activity by DC hardware hackers, this doesn't seem
  37 * likely to happen anytime soon.
  38 */
  39static int gapspci_config_access(unsigned char bus, unsigned int devfn)
  40{
  41        return (bus == 0) && (devfn == 0);
  42}
  43
  44/*
  45 * We can also actually read and write in b/w/l sizes! Thankfully this part
  46 * was at least done right, and we don't have to do the stupid masking and
  47 * shifting that we do on the 7751! Small wonders never cease to amaze.
  48 */
  49static int gapspci_read(struct pci_bus *bus, unsigned int devfn, int where, int size, u32 *val)
  50{
  51        *val = 0xffffffff;
  52
  53        if (!gapspci_config_access(bus->number, devfn))
  54                return PCIBIOS_DEVICE_NOT_FOUND;
  55
  56        switch (size) {
  57        case 1: *val = inb(GAPSPCI_BBA_CONFIG+where); break;
  58        case 2: *val = inw(GAPSPCI_BBA_CONFIG+where); break;
  59        case 4: *val = inl(GAPSPCI_BBA_CONFIG+where); break;
  60        }
  61
  62        return PCIBIOS_SUCCESSFUL;
  63}
  64
  65static int gapspci_write(struct pci_bus *bus, unsigned int devfn, int where, int size, u32 val)
  66{
  67        if (!gapspci_config_access(bus->number, devfn))
  68                return PCIBIOS_DEVICE_NOT_FOUND;
  69
  70        switch (size) {
  71        case 1: outb(( u8)val, GAPSPCI_BBA_CONFIG+where); break;
  72        case 2: outw((u16)val, GAPSPCI_BBA_CONFIG+where); break;
  73        case 4: outl((u32)val, GAPSPCI_BBA_CONFIG+where); break;
  74        }
  75
  76        return PCIBIOS_SUCCESSFUL;
  77}
  78
  79struct pci_ops gapspci_pci_ops = {
  80        .read   = gapspci_read,
  81        .write  = gapspci_write,
  82};
  83