linux/arch/sh/drivers/pci/ops-dreamcast.c
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   1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 * PCI operations for the Sega Dreamcast
   4 *
   5 * Copyright (C) 2001, 2002  M. R. Brown
   6 * Copyright (C) 2002, 2003  Paul Mundt
   7 */
   8
   9#include <linux/sched.h>
  10#include <linux/kernel.h>
  11#include <linux/param.h>
  12#include <linux/interrupt.h>
  13#include <linux/init.h>
  14#include <linux/irq.h>
  15#include <linux/pci.h>
  16#include <linux/module.h>
  17#include <linux/io.h>
  18#include <mach/pci.h>
  19
  20/*
  21 * The !gapspci_config_access case really shouldn't happen, ever, unless
  22 * someone implicitly messes around with the last devfn value.. otherwise we
  23 * only support a single device anyways, and if we didn't have a BBA, we
  24 * wouldn't make it terribly far through the PCI setup anyways.
  25 *
  26 * Also, we could very easily support both Type 0 and Type 1 configurations
  27 * here, but since it doesn't seem that there is any such implementation in
  28 * existence, we don't bother.
  29 *
  30 * I suppose if someone actually gets around to ripping the chip out of
  31 * the BBA and hanging some more devices off of it, then this might be
  32 * something to take into consideration. However, due to the cost of the BBA,
  33 * and the general lack of activity by DC hardware hackers, this doesn't seem
  34 * likely to happen anytime soon.
  35 */
  36static int gapspci_config_access(unsigned char bus, unsigned int devfn)
  37{
  38        return (bus == 0) && (devfn == 0);
  39}
  40
  41/*
  42 * We can also actually read and write in b/w/l sizes! Thankfully this part
  43 * was at least done right, and we don't have to do the stupid masking and
  44 * shifting that we do on the 7751! Small wonders never cease to amaze.
  45 */
  46static int gapspci_read(struct pci_bus *bus, unsigned int devfn, int where, int size, u32 *val)
  47{
  48        *val = 0xffffffff;
  49
  50        if (!gapspci_config_access(bus->number, devfn))
  51                return PCIBIOS_DEVICE_NOT_FOUND;
  52
  53        switch (size) {
  54        case 1: *val = inb(GAPSPCI_BBA_CONFIG+where); break;
  55        case 2: *val = inw(GAPSPCI_BBA_CONFIG+where); break;
  56        case 4: *val = inl(GAPSPCI_BBA_CONFIG+where); break;
  57        }
  58
  59        return PCIBIOS_SUCCESSFUL;
  60}
  61
  62static int gapspci_write(struct pci_bus *bus, unsigned int devfn, int where, int size, u32 val)
  63{
  64        if (!gapspci_config_access(bus->number, devfn))
  65                return PCIBIOS_DEVICE_NOT_FOUND;
  66
  67        switch (size) {
  68        case 1: outb(( u8)val, GAPSPCI_BBA_CONFIG+where); break;
  69        case 2: outw((u16)val, GAPSPCI_BBA_CONFIG+where); break;
  70        case 4: outl((u32)val, GAPSPCI_BBA_CONFIG+where); break;
  71        }
  72
  73        return PCIBIOS_SUCCESSFUL;
  74}
  75
  76struct pci_ops gapspci_pci_ops = {
  77        .read   = gapspci_read,
  78        .write  = gapspci_write,
  79};
  80