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

   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  */
  36 static 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  */
  46 static 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
  62 static 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
  76 struct pci_ops gapspci_pci_ops = {
  77         .read   = gapspci_read,
  78         .write  = gapspci_write,
  79 };