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  */
  39 static 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  */
  49 static 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
  65 static 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
  79 struct pci_ops gapspci_pci_ops = {
  80         .read   = gapspci_read,
  81         .write  = gapspci_write,
  82 };